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Sample records for agonist-stimulated phasic myometrial

  1. Phasic Triplet Markov Chains.

    PubMed

    El Yazid Boudaren, Mohamed; Monfrini, Emmanuel; Pieczynski, Wojciech; Aïssani, Amar

    2014-11-01

    Hidden Markov chains have been shown to be inadequate for data modeling under some complex conditions. In this work, we address the problem of statistical modeling of phenomena involving two heterogeneous system states. Such phenomena may arise in biology or communications, among other fields. Namely, we consider that a sequence of meaningful words is to be searched within a whole observation that also contains arbitrary one-by-one symbols. Moreover, a word may be interrupted at some site to be carried on later. Applying plain hidden Markov chains to such data, while ignoring their specificity, yields unsatisfactory results. The Phasic triplet Markov chain, proposed in this paper, overcomes this difficulty by means of an auxiliary underlying process in accordance with the triplet Markov chains theory. Related Bayesian restoration techniques and parameters estimation procedures according to the new model are then described. Finally, to assess the performance of the proposed model against the conventional hidden Markov chain model, experiments are conducted on synthetic and real data. PMID:26353069

  2. Muscarinic receptor agonists stimulate matrix metalloproteinase 1-dependent invasion of human colon cancer cells

    SciTech Connect

    Raufman, Jean-Pierre; Cheng, Kunrong; Saxena, Neeraj; Chahdi, Ahmed; Belo, Angelica; Khurana, Sandeep; Xie, Guofeng

    2011-11-18

    Highlights: Black-Right-Pointing-Pointer Muscarinic receptor agonists stimulated robust human colon cancer cell invasion. Black-Right-Pointing-Pointer Anti-matrix metalloproteinase1 antibody pre-treatment blocks cell invasion. Black-Right-Pointing-Pointer Bile acids stimulate MMP1 expression, cell migration and MMP1-dependent invasion. -- Abstract: Mammalian matrix metalloproteinases (MMPs) which degrade extracellular matrix facilitate colon cancer cell invasion into the bloodstream and extra-colonic tissues; in particular, MMP1 expression correlates strongly with advanced colon cancer stage, hematogenous metastasis and poor prognosis. Likewise, muscarinic receptor signaling plays an important role in colon cancer; muscarinic receptors are over-expressed in colon cancer compared to normal colon epithelial cells. Muscarinic receptor activation stimulates proliferation, migration and invasion of human colon cancer cells. In mouse intestinal neoplasia models genetic ablation of muscarinic receptors attenuates carcinogenesis. In the present work, we sought to link these observations by showing that MMP1 expression and activation plays a mechanistic role in muscarinic receptor agonist-induced colon cancer cell invasion. We show that acetylcholine, which robustly increases MMP1 expression, stimulates invasion of HT29 and H508 human colon cancer cells into human umbilical vein endothelial cell monolayers - this was abolished by pre-incubation with atropine, a non-selective muscarinic receptor inhibitor, and by pre-incubation with anti-MMP1 neutralizing antibody. Similar results were obtained using a Matrigel chamber assay and deoxycholyltaurine (DCT), an amidated dihydroxy bile acid associated with colon neoplasia in animal models and humans, and previously shown to interact functionally with muscarinic receptors. DCT treatment of human colon cancer cells resulted in time-dependent, 10-fold increased MMP1 expression, and DCT-induced cell invasion was also blocked by pre

  3. Estrogen maintains myometrial tumors in a lymphangioleiomyomatosis model

    PubMed Central

    Prizant, Hen; Taya, Manisha; Lerman, Irina; Light, Allison; Sen, Aritro; Mitra, Soumya; Foster, Thomas H; Hammes, Stephen R

    2016-01-01

    Lymphangioleiomyomatosis (LAM) is a rare disease in women. Patients with LAM develop metastatic smooth-muscle cell adenomas within the lungs, resulting in reduced pulmonary function. LAM cells contain mutations in tuberous sclerosis genes (TSC1 or TSC2), leading to up-regulation of mTORC1 activity and elevated proliferation. The origin of LAM cells remains unknown; however, inactivation of Tsc2 gene in the mouse uterus resulted in myometrial tumors exhibiting LAM features, and approximately 50% of animals developed metastatic myometrial lung tumors. This suggests that LAM tumors might originate from the uterine myometrium, possibly explaining the overwhelming prevalence of LAM in female. Here, we demonstrate that mouse Tsc2-null myometrial tumors exhibit nearly all the features of LAM, including mTORC1/S6K activation, as well as expression of melanocytic markers and matrix metalloproteinases (MMPs). Estrogen ablation reduces S6K signaling and results in Tsc2-null myometrial tumor regression. Thus, even without TSC2, estradiol is required to maintain tumors and mTORC1/S6K signaling. Additionally, we find that MMP-2 and −9, as well as neutrophil elastase (NE), are overexpressed in Tsc2-null myometrial tumors in an estrogen-dependent fashion. In vivo fluorescent imaging using MMP- or NE-sensitive optical biomarkers confirms that protease activity is specific to myometrial tumors. Similar to LAM cells, uterine Tsc2-null myometrial cells also overexpress melanocytic markers in an estrogen-dependent fashion. Finally, we identify glycoprotein NMB (GPNMB) as a melanocytic marker up-regulated in Tsc2-null mouse uteri and human LAM samples. Our data highlight the potential importance of estradiol in LAM cells, suggesting that anti-estrogen therapy may be a treatment modality. Furthermore, proteases and GPNMB might be useful LAM biomarkers. PMID:26880751

  4. Effects of abnormal cannabidiol on oxytocin-induced myometrial contractility.

    PubMed

    Houlihan, Diarmaid D; Dennedy, Michael C; Morrison, John J

    2010-04-01

    The objective of this study was to investigate the effects of abnormal cannabidiol (abn-cbd) on oxytocin-induced myometrial contractility occurring during pregnancy. Isometric tension recordings were performed in isolated myometrial strips from biopsies obtained at elective cesarean section. The effects of cumulative doses of abn-cbd (10(-9)-10(-5) M) on oxytocin-induced myometrial contractions alone, and on those following pre-incubation with SR 144528, AM 251, methylene blue, and iberiotoxin were measured, and dose-response curves were constructed. The pD(2) (-log EC(50)) values and the maximal inhibitory (MMI) values that were achieved were compared for each tissue type. Abn-cbd exerted a potent relaxant effect on oxytocin-induced myometrial contractions in vitro. Pre-incubation with the guanylate cyclase inhibitor, methylene blue, and the BK(Ca) channel antagonist, iberiotoxin, significantly attenuated this effect (for pD(2), P<0.01; for MMI, P<0.01). Abn-cbd exerts a potent inhibitory effect on human uterine contractility. This effect is partially mediated through modulation of guanylate cyclase and activation of BK(Ca) channel activity. These findings have implications for physiologic regulation of myometrial quiescence.

  5. Phasic phosphorylation of caldesmon and ERK 1/2 during contractions in human myometrium.

    PubMed

    Paul, Jonathan; Maiti, Kaushik; Read, Mark; Hure, Alexis; Smith, Julia; Chan, Eng-Cheng; Smith, Roger

    2011-01-01

    Human myometrium develops phasic contractions during labor. Phosphorylation of caldesmon (h-CaD) and extracellular signal-regulated kinase 1/2 (ERK 1/2) has been implicated in development of these contractions, however the phospho-regulation of these proteins is yet to be examined during periods of both contraction and relaxation. We hypothesized that protein phosphorylation events are implicated in the phasic nature of myometrial contractions, and aimed to examine h-CaD and ERK 1/2 phosphorylation in myometrium snap frozen at specific stages, including; (1) prior to onset of contractions, (2) at peak contraction and (3) during relaxation. We aimed to compare h-CaD and ERK 1/2 phosphorylation in vitro against results from in vivo studies that compared not-in-labor (NIL) and laboring (L) myometrium. Comparison of NIL (n = 8) and L (n = 8) myometrium revealed a 2-fold increase in h-CaD phosphorylation (ser-789; P = 0.012) during onset of labor in vivo, and was associated with significantly up-regulated ERK2 expression (P = 0.022), however no change in ERK2 phosphorylation was observed (P = 0.475). During in vitro studies (n = 5), transition from non-contracting tissue to tissue at peak contraction was associated with increased phosphorylation of both h-CaD and ERK 1/2. Furthermore, tissue preserved at relaxation phase exhibited diminished levels of h-CaD and ERK 1/2 phosphorylation compared to tissue preserved at peak contraction, thereby producing a phasic phosphorylation profile for h-CaD and ERK 1/2. h-CaD and ERK 1/2 are phosphorylated during myometrial contractions, however their phospho-regulation is dynamic, in that h-CaD and ERK 1/2 are phosphorylated and dephosphorylated in phase with contraction and relaxation respectively. Comparisons of NIL and L tissue are at risk of failing to detect these changes, as L samples are not necessarily preserved in the midst of an active contraction.

  6. Maternal obesity impairs specific regulatory pathways in human myometrial arteries.

    PubMed

    Hayward, Christina E; Cowley, Elizabeth J; Mills, Tracey A; Sibley, Colin P; Wareing, Mark

    2014-03-01

    Obese women (body mass index ≥30 kg/m(2)) are at greater risk than normal weight women of pregnancy complications associated with maternal and infant morbidity, particularly the development of cardiovascular disease and metabolic disorders in later life; why this occurs is unknown. Nonpregnant, obese individuals exhibit systemic vascular endothelial dysfunction. We tested the hypothesis that obese pregnant women have altered myometrial arterial function compared to pregnant women of normal (18-24 kg/m(2)) and overweight (25-29 kg/m(2)) body mass index. Responses to vasoconstrictors, U46619 (thromboxane mimetic) and arginine vasopressin, and vasodilators, bradykinin and the nitric oxide donor sodium nitroprusside, were assessed by wire myography in myometrial arteries from normal weight (n = 18), overweight (n = 18), and obese (n = 20) women with uncomplicated pregnancies. Thromboxane-prostanoid receptor expression was assessed using immunostaining in myometrial arteries of normal weight and obese women. Vasoconstriction and vasodilatation were impaired in myometrial arteries from obese women with otherwise uncomplicated pregnancies. Disparate agonist responses suggest that vascular function in obese women is not globally dysregulated but may be specific to thromboxane and nitric oxide pathways. Because obesity rates are escalating, it is important to identify the mechanisms underlying impaired vascular function and establish why some obese women compensate for vascular dysfunction and some do not. Future studies are needed to determine whether central adiposity results in an altered endocrine milieu that may promote vascular dysfunction by altering the function of perivascular adipose tissue.

  7. Calmodulin regulation of basal and agonist-stimulated G protein coupling by the mu-opioid receptor (OP(3)) in morphine-pretreated cell.

    PubMed

    Wang, D; Surratt, C K; Sadée, W

    2000-08-01

    Calmodulin (CaM) has been shown to suppress basal G protein coupling and attenuate agonist-stimulated G protein coupling of the mu-opioid receptor (OP(3)) through direct interaction with the third intracellular (i3) loop of the receptor. Here we have investigated the role of CaM in regulating changes in OP(3)-G protein coupling during morphine treatment, shown to result in CaM release from plasma membranes. Basal and agonist-stimulated G protein coupling by OP(3) was measured before and after morphine pretreatment by incorporation of guanosine 5'-O-(3-[(35)S]thiotriphosphate) into membranes, obtained from HEK 293 cells transfected with human OP(3) cDNA. The opioid antagonist beta-chlornaltrexamine fully suppressed basal G protein coupling of OP(3), providing a direct measure of basal signaling. Pretreatment of the cells with morphine enhanced basal G protein coupling (sensitization). In contrast, agonist-stimulated coupling was diminished (desensitization), resulting in a substantially flattened morphine dose-response curve. To test whether CaM is involved in these changes, we constructed OP(3)-i3 loop mutants with reduced affinity for CaM (K273A, R275A, and K273A/R275A). Basal signaling of these mutant OP(3) receptors was higher than that of the wild-type receptor and, moreover, unaffected by morphine pretreatment, whereas desensitization to agonist stimulation was only slightly attenuated. Therefore, CaM-OP(3) interactions appear to play only a minor role in the desensitization of OP(3). In contrast, release of CaM from the plasma membrane appears to enhance the inherent basal G protein coupling of OP(3), thereby resolving the paradox that OP(3) displays both desensitization and sensitization during morphine treatment.

  8. Oxytocin-stimulated NFAT transcriptional activation in human myometrial cells.

    PubMed

    Pont, Jason N A; McArdle, Craig A; López Bernal, Andrés

    2012-10-01

    Oxytocin (OXT) is a peptide hormone that binds the OXT receptor on myometrial cells, initiating an intracellular signaling cascade, resulting in accumulation of intracellular calcium and smooth muscle contraction. In other systems, an elevation of intracellular Ca(2+) stimulates nuclear translocation of the transcription factor, nuclear factor of activated T cells (NFAT), which is transcriptionally active in arterial and ileal smooth muscle. Here we have investigated the role of NFAT in the mechanism of action of OXT. Human myometrial cells expressed all five NFAT isoforms (NFATC1-C4 and -5). Myometrial cells were transduced with a recombinant adenovirus expressing a NFATC1-EFP reporter, and a semi-automated imaging system was used to monitor effects of OXT on reporter localization in live cells. OXT induced a concentration-dependent nuclear translocation of NFATC1-EFP in a reversible manner, which was inhibited by OXT antagonists and calcineurin inhibitors. Pulsatile stimulation with OXT caused intermittent, pulse-frequency-dependent, nuclear translocation of NFATC1-EFP, which was more efficient than sustained stimulation. OXT induced nuclear translocation of endogenous NFAT that was transcriptionally active, because OXT stimulated activity of a NFAT-response element-luciferase reporter and induced calcineurin-NFAT dependent expression of RGS2, RCAN1, and PTGS2 (COX2) mRNA. Furthermore, OXT-dependent transcription was dependent on protein neosynthesis; cycloheximide abolished RGS2 transcription but augmented RCAN1 and COX2 transcriptional readouts. This study identifies a novel signaling mechanism within the myometrium, whereby calcineurin-NFAT signaling mediates OXT-induced transcriptional activity. Furthermore, we show NFATC1-EFP is responsive to pulses of OXT, a mechanism by which myometrial cells could decode OXT pulse frequency.

  9. Regulation of myometrial contraction by ATP-sensitive potassium (KATP) channel via activation of SUR2B and Kir 6.2 in mouse.

    PubMed

    Hong, Seung Hwa; Kyeong, Kyu-Sang; Kim, Chan Hyung; Kim, Young Chul; Choi, Woong; Yoo, Ra Young; Kim, Hun Sik; Park, Yeon Jin; Ji, Il Woon; Jeong, Eun-Hwan; Kim, Hak Soon; Xu, Wen-Xie; Lee, Sang Jin

    2016-08-01

    ATP-sensitive potassium (KATP) channels are well characterized in cardiac, pancreatic and many other muscle cells. In the present study, functional expression of the KATP channel was examined in non-pregnant murine longitudinal myometrium. Isometric contraction measurements and Western blot were used. KATP channel openers (KCOs), such as pinacidil, cromakalim, diazoxide and nicorandil, inhibited spontaneous myometrial contractions in a reversible and glibenclamide-sensitive manner. KCOs inhibited oxytocin (OXT)- and prostaglandin F2α (PGF2α)-induced phasic contractions in a glibenclamide-sensitive manner. SUR2B and Kir6.2 were detected by Western blot, whereas SUR1, SUR2A and Kir6.1 were not. These results show that pinacidl, cromakalim, diazoxide and nicorandil-sensitive KATP channels exist in murine myometrium, which are composed of SUR2B and Kir6.2. Based on the modulatory effects of the KATP channel on spontaneous contraction, OXT- and PGF2α-induced contractions, KATP channels seem to play an essential role in murine myometrial motility via activation of SUR2B and Kir6.2.

  10. Regulation of myometrial contraction by ATP-sensitive potassium (KATP) channel via activation of SUR2B and Kir 6.2 in mouse

    PubMed Central

    HONG, Seung Hwa; KYEONG, Kyu-Sang; KIM, Chan Hyung; KIM, Young Chul; CHOI, Woong; YOO, Ra Young; KIM, Hun Sik; PARK, Yeon Jin; JI, Il Woon; JEONG, Eun-Hwan; KIM, Hak Soon; XU, Wen-Xie; LEE, Sang Jin

    2016-01-01

    ATP-sensitive potassium (KATP) channels are well characterized in cardiac, pancreatic and many other muscle cells. In the present study, functional expression of the KATP channel was examined in non-pregnant murine longitudinal myometrium. Isometric contraction measurements and Western blot were used. KATP channel openers (KCOs), such as pinacidil, cromakalim, diazoxide and nicorandil, inhibited spontaneous myometrial contractions in a reversible and glibenclamide-sensitive manner. KCOs inhibited oxytocin (OXT)- and prostaglandin F2α (PGF2α)-induced phasic contractions in a glibenclamide-sensitive manner. SUR2B and Kir6.2 were detected by Western blot, whereas SUR1, SUR2A and Kir6.1 were not. These results show that pinacidl, cromakalim, diazoxide and nicorandil-sensitive KATP channels exist in murine myometrium, which are composed of SUR2B and Kir6.2. Based on the modulatory effects of the KATP channel on spontaneous contraction, OXT- and PGF2α-induced contractions, KATP channels seem to play an essential role in murine myometrial motility via activation of SUR2B and Kir6.2. PMID:27086859

  11. Regulation of myometrial contraction by ATP-sensitive potassium (KATP) channel via activation of SUR2B and Kir 6.2 in mouse.

    PubMed

    Hong, Seung Hwa; Kyeong, Kyu-Sang; Kim, Chan Hyung; Kim, Young Chul; Choi, Woong; Yoo, Ra Young; Kim, Hun Sik; Park, Yeon Jin; Ji, Il Woon; Jeong, Eun-Hwan; Kim, Hak Soon; Xu, Wen-Xie; Lee, Sang Jin

    2016-08-01

    ATP-sensitive potassium (KATP) channels are well characterized in cardiac, pancreatic and many other muscle cells. In the present study, functional expression of the KATP channel was examined in non-pregnant murine longitudinal myometrium. Isometric contraction measurements and Western blot were used. KATP channel openers (KCOs), such as pinacidil, cromakalim, diazoxide and nicorandil, inhibited spontaneous myometrial contractions in a reversible and glibenclamide-sensitive manner. KCOs inhibited oxytocin (OXT)- and prostaglandin F2α (PGF2α)-induced phasic contractions in a glibenclamide-sensitive manner. SUR2B and Kir6.2 were detected by Western blot, whereas SUR1, SUR2A and Kir6.1 were not. These results show that pinacidl, cromakalim, diazoxide and nicorandil-sensitive KATP channels exist in murine myometrium, which are composed of SUR2B and Kir6.2. Based on the modulatory effects of the KATP channel on spontaneous contraction, OXT- and PGF2α-induced contractions, KATP channels seem to play an essential role in murine myometrial motility via activation of SUR2B and Kir6.2. PMID:27086859

  12. Transvaginal ultrasound examination of myometrial infiltration by endometrial cancer.

    PubMed

    Miklos, P; Klacko, M; Babala, P; Masak, L; Ondrus, D; Waczulikova, I

    2014-01-01

    The depth of myometrial infiltration by endometrial cancer is an important prognostic factor. The examination of the depth of infiltration classifies the patients in the low- and high-risk groups, which influences the therapeutic approach. Transvaginal ultrasonography represents a first-choice diagnostic test for the assessment of the depth of myometrial infiltration as the time consumption and financial demands of magnetic resonance imaging need to be taken into account. In comparison with the MRI, the diagnostic accuracy of the transvaginal ultrasound depends more on the individual experience and professional potential of the examining physician. This fact can contribute to the heterogeneity of published results of transvaginal ultrasound on the determination of infiltration depth. Having in mind the aim to verify these indicators in our local conditions and environment, we decided to prospectively study 150 endometrial cancer patients who were examined with the transvaginal ultrasound in the period 1/2009 - 10/ 2011. Correlated firstly with the preoperative and then secondly with the definitive histopathological examination was the depth-of-infiltration-related data that had been taken from the ultrasound findings. The output being monitored was the exclusion or confirmation of the invasion exceeding half the thickness of myometrium. In our study, the diagnostic accuracy of the method reached 82.67 %, while the other indicators were as follows: sensitivity 92.31 %, specificity 79.28 %, positive predictive value (PPV) 61.02 %, negative predictive value (NPV) 96.7 %, the likelihood ratio of a positive test 4.455 and the likelihood ratio of a negative test 0.097. The results of the depth of myometrial infiltration examination and their comparison with the data from similarly oriented clinical studies entitle us to include this examination in the set of standard preoperative methods used for the examination of patients with endometrial cancer (Tab. 3, Fig. 5, Ref

  13. Myometrial electrical activity during pregnancy and parturition in the pygmy goat.

    PubMed

    Taverne, M A; Scheerboom, J E

    1985-01-01

    To quantify the pattern of myometrial activity during gestation and parturition, one bipolar electrode was implanted on each uterine horn of four bilaterally pregnant pygmy goats between days 102 and 120 of gestation. After a recovery period, electromyographic recordings were made for at least six hours per day and continuously when parturition was judged to be imminent. During late gestation myometrial activity occurred as discrete episodes of myometrial electrical activity (EMEA) with a mean duration ranging from 6.2 +/- 2.07 to 8.3 +/- 1.60 minutes. The mean interval between two successive EMEAs ranged from 45.8 +/- 19.95 to 74.7 +/- 42.27 minutes. In three of the four goats these characteristics were not significantly different from the two uterine horns. Parturition was preceded by a prolonged period (eight to 12 hours) of myometrial quiescence. It was only from 19 to 15 hours before expulsion of the first kid that total duration of EMG activity increased. This finally resulted in the regular occurrence of bursts which occupied 25 to 30 per cent of the recording time. The results demonstrate that, as in the sheep, cow and pig, the myometrium is active during late pregnancy. It is postulated that luteolysis coincides with the prolonged period of myometrial quiescence which precedes the onset of the parturient pattern of uterine activity.

  14. Effects of cadmium on myometrial activity of the nonpregnant human. Interactions with calcium and oxytocin.

    PubMed

    Sipowicz, M; Kostrzewska, A; Laudanski, T; Akerlund, M

    1995-02-01

    With respect to recent reports suggesting an involvement of cadmium in preterm labor, the effects of this ion on the activity of myometrial strips from term pregnant women were examined. The interactions of cadmium with calcium and oxytocin on myometrial activity were also studied. Cadmium alone inhibited spontaneous contractile activity already in a concentration of 10(-9) M and in 10(-3) M myometrial contractions were almost completely abolished. Responses to Ca2+ and oxytocin were significantly increased by exposure to cadmium in low concentration (10(-9) M-10(-8) M), whereas higher concentration of Cd2+ had inhibitory action. These results suggest that cadmium not only blocks Ca2+ channels in the human myometrium, but also interferes with intracellular mechanisms involved in excitation-contraction coupling. The increased responses to Ca2+ and oxytocin in the presence of low amounts of Cd2+ support a role of cadmium in mechanisms of preterm labor. PMID:7900519

  15. From laboratory to industry Phasics experience (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Wattellier, Benoit F.; Lebrun, Marie-Begoña.

    2016-03-01

    We describe several examples of technology transfer from academic laboratories to PHASICS. PHASICS was created in 2003 as a spin-off of LULI an academic laboratory working on plasma physics and developing high power lasers to create such objects which temperature and pressure conditions are close to those at the center of stars. In order to optimize the intensity at laser focus, several thesis treated the subject of adaptive optics for lasers. LULI decided to collaborate with ONERA who just invented a technique for wave front sensing called multiwave lateral shearing interferometry. Though developed at first for infrared metrology applications, this technique proved to be very efficient with lasers because it was able to analyze wave front of modulated beams with sharp edges. Before being industrialized the technique was further improved to a compact version called quadriwave lateral shearing interferometry. As soon as PHASICS was created, we felt the potential of making wave front images from transparent objects because of QWLSI high spatial resolution. PHASICS and Institut Fresnel started a collaboration to study applications in microscopy imaging. Research subjects include biological imaging, CARS microscopy, anisotropy imaging, or laser damage testing. The results of research were then included in PHASICS products but sometimes only a tool developed during the project became a product. We will present research works that led to transfers as well as the method we used to ensure fruitful collaboration and transfer.

  16. Amphetamine paradoxically augments exocytotic dopamine release and phasic dopamine signals.

    PubMed

    Daberkow, D P; Brown, H D; Bunner, K D; Kraniotis, S A; Doellman, M A; Ragozzino, M E; Garris, P A; Roitman, M F

    2013-01-01

    Drugs of abuse hijack brain-reward circuitry during the addiction process by augmenting action potential-dependent phasic dopamine release events associated with learning and goal-directed behavior. One prominent exception to this notion would appear to be amphetamine (AMPH) and related analogs, which are proposed instead to disrupt normal patterns of dopamine neurotransmission by depleting vesicular stores and promoting nonexocytotic dopamine efflux via reverse transport. This mechanism of AMPH action, though, is inconsistent with its therapeutic effects and addictive properties, which are thought to be reliant on phasic dopamine signaling. Here we used fast-scan cyclic voltammetry in freely moving rats to interrogate principal neurochemical responses to AMPH in the striatum and relate these changes to behavior. First, we showed that AMPH dose-dependently enhanced evoked dopamine responses to phasic-like current pulse trains for up to 2 h. Modeling the data revealed that AMPH inhibited dopamine uptake but also unexpectedly potentiated vesicular dopamine release. Second, we found that AMPH increased the amplitude, duration, and frequency of spontaneous dopamine transients, the naturally occurring, nonelectrically evoked, phasic increases in extracellular dopamine. Finally, using an operant sugar reward paradigm, we showed that low-dose AMPH augmented dopamine transients elicited by sugar-predictive cues. However, operant behavior failed at high-dose AMPH, which was due to phasic dopamine hyperactivity and the decoupling of dopamine transients from the reward predictive cue. These findings identify upregulation of exocytotic dopamine release as a key AMPH action in behaving animals and support a unified mechanism of abused drugs to activate phasic dopamine signaling. PMID:23303926

  17. Determination of mass changes in phosphatidylinositol 4,5-bisphosphate and evidence for agonist-stimulated metabolism of inositol 1,4,5-trisphosphate in airway smooth muscle.

    PubMed Central

    Chilvers, E R; Batty, I H; Challiss, R A; Barnes, P J; Nahorski, S R

    1991-01-01

    Stimulation of muscarinic receptors in bovine tracheal smooth muscle (BTSM) causes a sustained increase in muscle tone, but a transient increase in the second messenger Ins(1,4,5)P3. To examine whether this brief increase in Ins(1,4,5)P3 mass results from transient formation or is due to agonist-stimulation of Ins(1,4,5)P3 metabolism, we have studied the relationship between mass changes in PtdIns(4,5)P2 and Ins(1,4,5)P3 accumulation, and changes in [3H]InsP3, [3H]PtdIns, [3H]PtdInsP1 and [3H]PtdInsP2 in carbachol-stimulated myo-[3H]inositol-prelabelled BTSM slices. Carbachol (0.1 mM) caused a rapid transient increase in Ins(1,4,5)P3 concentration (basal, 12.9 +/- 0.8 pmol/mg of protein; 5 s carbachol treatment, 27.1 +/- 1.5 pmol/mg of protein), with values returning to basal levels by 30 s, but a sustained accumulation of total [3H]InsP3s, with [3H]Ins(1,3,4)P3 being the predominant isomer present at later time points. In contrast, PtdIns(4,5)P2 mass, determined by radioreceptor assay of Ins(1,4,5)P3 in desalted alkaline hydrolysates of acidified chloroform/methanol tissue extracts, declined rapidly (basal, 941 +/- 22 pmol/mg of protein; 120 s carbachol, 365 +/- 22 pmol/mg of protein; t1/2 14 s) and remained at this new steady-state level for at least 20 min in the continued presence of carbachol. Addition of 10 microM-atropine 2 min after carbachol caused a prompt return of PtdIns(4,5)P2 concentration to prestimulated values (t1/2 210 s). Ongoing resynthesis of PtdIns(4,5)P2 after carbachol stimulation was demonstrated in [3H]inositol-labelled tissue by observing a persistent increase in the specific radioactivity of [3H]PtdInsP2, shown to be exclusively [3H]PtdIns(4,5)P2, over a 10 min period. These findings strongly suggest the occurrence of persistent receptor-mediated increases in PtdIns(4,5)P2 hydrolysis and Ins(1,4,5)P3 formation which, in conjunction with the transient accumulation of Ins(1,4,5)P3 observed, provide evidence that regulation of the

  18. Preferred recycling pathway by internalized PGE2 EP4 receptor following agonist stimulation in cultured dorsal root ganglion neurons contributes to enhanced EP4 receptor sensitivity.

    PubMed

    St-Jacques, Bruno; Ma, Weiya

    2016-06-21

    Prostaglandin E2 (PGE2), a well-known pain mediator abundantly produced in injured tissues, sensitizes nociceptive dorsal root ganglion (DRG) neurons (nociceptors) through its four EP receptors (EP1-4). Our prior study showed that PGE2 or EP4 agonist stimulates EP4 externalization and this event was not only suppressed by the inhibitor of anterograde export, but also by the recycling inhibitor (St-Jacques and Ma, 2013). These data suggest that EP4 recycling also contributes to agonist-enhanced EP4 surface abundance. In the current study, we tested this hypothesis using antibody-feeding-based internalization assay, recycling assay and FITC-PGE2 binding assay. We observed that selective EP4 agonist 1-hydroxy-PGE1 (1-OH-PGE1) or CAY10850 time- and concentration-dependently increased EP4 internalization in cultured DRG neuron. Internalized EP4 was predominantly localized in the early endosomes and recycling endosomes, but rarely in the late endosomes and lysosomes. These observations were confirmed by FITC-PGE2 binding assay. We further revealed that 1-OH-PGE1 or CAY10850 time- and concentration-dependently increased EP4 recycling. Double exposures to 1-OH-PGE1 induced a greater increase in calcitonin gene-related peptide (CGRP) release than a single exposure or vehicle exposure, an event blocked by pre-treatment with the recycling inhibitor monensin. Our data suggest that EP4 recycling contributes to agonist-induced cell surface abundance and consequently enhanced receptor sensitivity. Facilitating EP4 externalization and recycling is a novel mechanism underlying PGE2-induced nociceptor sensitization.

  19. RAR agonists stimulate SOX9 gene expression in breast cancer cell lines: evidence for a role in retinoid-mediated growth inhibition.

    PubMed

    Afonja, Olubunmi; Raaka, Bruce M; Huang, Ambrose; Das, Sharmistha; Zhao, Xinyu; Helmer, Elizabeth; Juste, Dominique; Samuels, Herbert H

    2002-11-01

    Retinoic acid receptors (RARs) are ligand-dependent transcription factors which are members of the steroid/thyroid hormone receptor gene family. RAR-agonists inhibit the proliferation of many human breast cancer cell lines, particularly those whose growth is stimulated by estradiol (E2) or growth factors. PCR-amplified subtractive hybridization was used to identify candidate retinoid-regulated genes that may be involved in growth inhibition. One candidate gene identified was SOX9, a member of the high mobility group (HMG) box gene family of transcription factors. SOX9 gene expression is rapidly stimulated by RAR-agonists in T-47D cells and other retinoid-inhibited breast cancer cell lines. In support of this finding, a database search indicates that SOX9 is expressed as an EST in breast tumor cells. SOX9 is known to be expressed in chondrocytes where it regulates the transcription of type II collagen and in testes where it plays a role in male sexual differentiation. RAR pan-agonists and the RARalpha-selective agonist Am580, but not RXR agonists, stimulate the expression of SOX9 in a wide variety of retinoid-inhibited breast cancer cell lines. RAR-agonists did not stimulate SOX9 in breast cancer cell lines which were not growth inhibited by retinoids. Expression of SOX9 in T-47D cells leads to cycle changes similar to those found with RAR-agonists while expression of a dominant negative form of SOX9 blocks RA-mediated cell cycle changes, suggesting a role for SOX9 in retinoid-mediated growth inhibition.

  20. Urocortin 2 role in placental and myometrial inflammatory mechanisms at parturition.

    PubMed

    Voltolini, Chiara; Battersby, Sharon; Novembri, Romina; Torricelli, Michela; Severi, Filiberto M; Petraglia, Felice; Norman, Jane E

    2015-02-01

    The purpose of the study was to investigate urocortin (Ucn)2 involvement in placental and myometrial inflammatory pathways associated with parturition by evaluating: 1) Ucn2 and its receptor, CRH-receptor type 2 (CRH-R2), expression in laboring/nonlaboring human gestational tissues and in mouse utero-placental tissues approaching delivery; and 2) Ucn2 effect on myometrial contractility and on the expression of inflammatory mediators (prostaglandin F2α receptor and cytokines) and regulation of Ucn2 by TNF-α in cultured myometrial cell line. Placenta (n = 16), fetal membranes (n = 16), and myometrium (n = 22) were obtained from healthy pregnant women delivering at term by vaginal/elective caesarean delivery and from timed-pregnant mice on days 16-19. Expression of Ucn2/CRH-R2 in human/mouse tissues and inflammatory mediators in myometrial cell lines were measured by RT-PCR or ELISA, mouse Ucn2/CRH-R2 protein localization by immunohistochemistry. Ucn2 but not CRH-R2 was up-regulated (P < .05) in all human tissues in labor (compared with before labor) and increased significantly (P < .01) in mouse placenta approaching delivery. Ucn2 was up-regulated by TNF-α via nuclear factor-κB (NF-kB) in myometrium cell lines (P < .05 or P < .01 on the basis of treatment doses) and increased proinflammatory mediators and prostaglandin F (PGF2α) receptor expression (P < .05) via CRH-R2, without a direct effect on contractility. Placental and myometrial Ucn2 may play a role in the endocrine-inflammatory processes of parturition, representing a potential target for treating inflammation-induced obstetric complications.

  1. Phasic dopamine neuron activity elicits unique mesofrontal plasticity in adolescence.

    PubMed

    Mastwal, Surjeet; Ye, Yizhou; Ren, Ming; Jimenez, Dennisse V; Martinowich, Keri; Gerfen, Charles R; Wang, Kuan Hong

    2014-07-16

    The mesofrontal dopaminergic circuit, which connects the midbrain motivation center to the cortical executive center, is engaged in control of motivated behaviors. In addition, deficiencies in this circuit are associated with adolescent-onset psychiatric disorders in humans. Developmental studies suggest that the mesofrontal circuit exhibits a protracted maturation through adolescence. However, whether the structure and function of this circuit are modifiable by activity in dopaminergic neurons during adolescence remains unknown. Using optogenetic stimulation and in vivo two-photon imaging in adolescent mice, we found that phasic, but not tonic, dopamine neuron activity induces the formation of mesofrontal axonal boutons. In contrast, in adult mice, the effect of phasic activity diminishes. Furthermore, our results showed that dopaminergic and glutamatergic transmission regulate this axonal plasticity in adolescence and inhibition of dopamine D2-type receptors restores this plasticity in adulthood. Finally, we found that phasic activation of dopamine neurons also induces greater changes in mesofrontal circuit activity and psychomotor response in adolescent mice than in adult mice. Together, our findings demonstrate that the structure and function of the mesofrontal circuit are modifiable by phasic activity in dopaminergic neurons during adolescence and suggest that the greater plasticity in adolescence may facilitate activity-dependent strengthening of dopaminergic input and improvement in behavioral control.

  2. Phasic temperature control appraised with the Ceres-Wheat model.

    PubMed

    Volk, T; Bugbee, B; Tubiello, F

    1997-01-01

    Phasic control refers to the specification of a series of different environmental conditions during a crop's life cycle, with the goal of optimizing some aspect of productivity. Because of the enormous number of possible scenarios, phasic control is an ideal situation for modeling to provide guidance prior to experiments. Here we use the Ceres-Wheat model, modified for hydroponic growth chambers, to examine temperature effects. We first establish a baseline by running the model at constant temperatures from 10 degrees C to 30 degrees C. Grain yield per day peaks at 15 degrees C at a value that is 25% higher than the yield at the commonly used 23 degrees C. We then show results for phasic control limited to a single shift in temperature and, finally, we examine scenarios that allow each of the five phases of the life cycle to have a different temperature. Results indicate that grain yield might be increased by 15-20% over the best yield at constant temperature, primarily from a boosted harvest index, which has the additional advantage of less waste biomass. Such gains, if achievable, would help optimize food production for life support systems. Experimental work should first verify the relationship between yield and temperature, and then move to selected scenarios of phasic control, based on model predictions. PMID:11540452

  3. Autoradiography of serotonin 5-HT1A receptor-activated G proteins in guinea pig brain sections by agonist-stimulated [35S]GTPgammaS binding.

    PubMed

    Dupuis, D S; Palmier, C; Colpaert, F C; Pauwels, P J

    1998-03-01

    G protein activation mediated by serotonin 5-HT1A and 5-HT(1B/D) receptors in guinea pig brain was investigated by using quantitative autoradiography of agonist-stimulated [35S]GTPgammaS binding to brain sections. [35S]GTPgammaS binding was stimulated by the mixed 5-HT1A/5-HT(1B/D) agonist L694247 in brain structures enriched in 5-HT1A binding sites, i.e., hippocampus (+140 +/- 14%), dorsal raphe (+70 +/- 8%), lateral septum (+52 +/- 12%), cingulate (+36 +/- 8%), and entorhinal cortex (+34 +/- 5%). L694247 caused little or no stimulation of [35S]GTPgammaS binding in brain regions with high densities of 5-HT(1B/D) binding sites (e.g., substantia nigra, striatum, central gray, and dorsal subiculum). The [35S]GTPgammaS binding response was antagonized by WAY100635 (10 microM) and methiothepin (10 microM). In contrast, the 5-HT1B inverse agonist SB224289 (10 microM) did not affect the L694247-mediated [35S]GTPgammaS binding response, and the mixed 5-HT(1B/D) antagonist GR127935 (10 microM) yielded a partial blockade. The distribution pattern of the [35S]GTPgammaS binding response and the antagonist profile suggest the L694247-mediated response in guinea pig brain to be mediated by 5-HT1A receptors. In addition to L694247, 8-hydroxy-2-(di-n-propylamino)tetralin, and flesinoxan also stimulated [35S]GTPgammaS binding; their maximal responses varied between 46 and 52% compared with L694247, irrespective of the brain structure being considered. Sumatriptan, rizatriptan, and zolmitriptan (10 microM) stimulated [35S]GTPgammaS binding in the hippocampus by 20-50%. Naratriptan, CP122638, and dihydroergotamine stimulated [35S]GTPgammaS binding to a similar level as L694247 in hippocampus, lateral septum, and dorsal raphe. It appears that under the present experimental conditions, G protein activation through 5-HT1A but not 5-HT(1B/D) receptors can be measured in guinea pig brain sections. PMID:9489749

  4. Calcium influx and release mechanism(s) in histamine-induced myometrial contraction in buffaloes.

    PubMed

    Sharma, Abhishek; Choudhury, Soumen; Nakade, Udayraj P; Yadav, Rajkumar Singh; Garg, Satish Kumar

    2014-05-01

    The present study was undertaken to characterize the presence of histamine H1R using molecular biology tools and unravel the influx and release mechanism(s) involved in calcium signalling cascades in histamine-induced myometrial contraction in buffaloes. The presence of H1R mRNA transcript and immunoreactive membrane protein in buffalo myometrium was confirmed by RT-PCR and Western blot analysis. Further, histamine produced concentration-dependent (1nM-10μM) contraction in buffalo myometrium with a potency of 7.13±0.11. When myometrial strips were pre-incubated either with Ca(2+) free solution or with nifedipine, a L-type Ca(2+) channel blocker, dose response curve (DRC) of histamine was significantly (P<0.05) shifted towards right with decline in maximal contraction (Emax). Reduction in Emax of histamine in the presence of nifedipine (55.75±3.10%) was significantly (P<0.001) greater than that in the presence of ruthenium red (93.61±3.43%), a blocker of IP3-gated and RyR-sensitive Ca(2+) channels. Moreover, histamine produced only 26.87±1.99% of the maximum contraction in the presence of both nifedipine and CPA (blocker of sarco-endoplasmic reticulum Ca(2+)-ATPase). Interestingly, following concurrent exposure to U-73122 (a PL-C inhibitor) and nifedipine, the DRC of histamine was significantly (P<0.05) shifted towards left with increase in maximal contraction (126.30±3.36%). Our findings in buffalo uterus thus suggest that influx of extracellular calcium plays a major role in histamine-induced myometrial contraction, while release of intracellular calcium through calcium-release channels of sarcoplasmic reticulum has a minor role. A possible involvement of non-selective cation channels in histamine-induced myometrial contraction cannot be ruled out, and therefore requires further investigations. PMID:24631173

  5. Calcium influx and release mechanism(s) in histamine-induced myometrial contraction in buffaloes.

    PubMed

    Sharma, Abhishek; Choudhury, Soumen; Nakade, Udayraj P; Yadav, Rajkumar Singh; Garg, Satish Kumar

    2014-05-01

    The present study was undertaken to characterize the presence of histamine H1R using molecular biology tools and unravel the influx and release mechanism(s) involved in calcium signalling cascades in histamine-induced myometrial contraction in buffaloes. The presence of H1R mRNA transcript and immunoreactive membrane protein in buffalo myometrium was confirmed by RT-PCR and Western blot analysis. Further, histamine produced concentration-dependent (1nM-10μM) contraction in buffalo myometrium with a potency of 7.13±0.11. When myometrial strips were pre-incubated either with Ca(2+) free solution or with nifedipine, a L-type Ca(2+) channel blocker, dose response curve (DRC) of histamine was significantly (P<0.05) shifted towards right with decline in maximal contraction (Emax). Reduction in Emax of histamine in the presence of nifedipine (55.75±3.10%) was significantly (P<0.001) greater than that in the presence of ruthenium red (93.61±3.43%), a blocker of IP3-gated and RyR-sensitive Ca(2+) channels. Moreover, histamine produced only 26.87±1.99% of the maximum contraction in the presence of both nifedipine and CPA (blocker of sarco-endoplasmic reticulum Ca(2+)-ATPase). Interestingly, following concurrent exposure to U-73122 (a PL-C inhibitor) and nifedipine, the DRC of histamine was significantly (P<0.05) shifted towards left with increase in maximal contraction (126.30±3.36%). Our findings in buffalo uterus thus suggest that influx of extracellular calcium plays a major role in histamine-induced myometrial contraction, while release of intracellular calcium through calcium-release channels of sarcoplasmic reticulum has a minor role. A possible involvement of non-selective cation channels in histamine-induced myometrial contraction cannot be ruled out, and therefore requires further investigations.

  6. ( sup 3 H)rauwolscine binding to myometrial. alpha. sub 2 -adrenoceptors in pregnant guinea pig

    SciTech Connect

    Arkinstall, S.J.; Jones, C.T. )

    1988-09-01

    Uterine sympathetic nerves can exert an excitatory influence in late pregnancy and during parturition. Neuronal norepinephrine release is increased at these times and a diminished {alpha}{sub 2}-adrenoceptor-mediated prejunctional inhibition could account for this. To assess whether an altered receptor population may contribute, ({sup 3}H)rauwolscine was used to measure {alpha}{sub 2}-adrenoceptors in myometrial membranes at time intervals throughout pregnancy. High affinity ({sup 3}H)rauwolscine binding yielded linear Scatchard plots that in nonpregnant myometrium indicated a maximum binding density B{sub max} of 217 {plus minus} 42.4 fmol/mg protein. {alpha}{sub 2}-Adrenoceptor density was increased twofold at midpregnancy (31 days) and thereafter fell sharply by up to 90% toward term (67 {plus minus} 2 days). When uterine growth is accounted for and data are expressed in terms of total myometrial population, {alpha}{sub 2}-adrenoceptor number was eightfold (midpregnancy) and fourfold (term) greater than the nonpregnant value of 804 {plus minus} 322.4 fmol/uterus. {alpha}{sub 2}-Adrenoceptors were also found to bind dopamine with high affinity. These observations could indicate a pregnancy-related change in uterine sympathetic autoinhibitory capacity and, since {alpha}{sub 2}-adrenoceptors appear also to be located postjunctionally, explain in part reports of altered myometrial responsiveness to norepinephrine infusion and also the uterotonic actions of dopamine.

  7. Functional insights into modulation of BKCa channel activity to alter myometrial contractility

    PubMed Central

    Lorca, Ramón A.; Prabagaran, Monali; England, Sarah K.

    2014-01-01

    The large-conductance voltage- and Ca2+-activated K+ channel (BKCa) is an important regulator of membrane excitability in a wide variety of cells and tissues. In myometrial smooth muscle, activation of BKCa plays essential roles in buffering contractility to maintain uterine quiescence during pregnancy and in the transition to a more contractile state at the onset of labor. Multiple mechanisms of modulation have been described to alter BKCa channel activity, expression, and cellular localization. In the myometrium, BKCa is regulated by alternative splicing, protein targeting to the plasma membrane, compartmentation in membrane microdomains, and posttranslational modifications. In addition, interaction with auxiliary proteins (i.e., β1- and β2-subunits), association with G-protein coupled receptor signaling pathways, such as those activated by adrenergic and oxytocin receptors, and hormonal regulation provide further mechanisms of variable modulation of BKCa channel function in myometrial smooth muscle. Here, we provide an overview of these mechanisms of BKCa channel modulation and provide a context for them in relation to myometrial function. PMID:25132821

  8. High-Throughput Screening of Myometrial Calcium-Mobilization to Identify Modulators of Uterine Contractility

    PubMed Central

    Herington, Jennifer L.; Swale, Daniel R.; Brown, Naoko; Shelton, Elaine L.; Choi, Hyehun; Williams, Charles H.; Hong, Charles C.; Paria, Bibhash C.; Denton, Jerod S.; Reese, Jeff

    2015-01-01

    The uterine myometrium (UT-myo) is a therapeutic target for preterm labor, labor induction, and postpartum hemorrhage. Stimulation of intracellular Ca2+-release in UT-myo cells by oxytocin is a final pathway controlling myometrial contractions. The goal of this study was to develop a dual-addition assay for high-throughput screening of small molecular compounds, which could regulate Ca2+-mobilization in UT-myo cells, and hence, myometrial contractions. Primary murine UT-myo cells in 384-well plates were loaded with a Ca2+-sensitive fluorescent probe, and then screened for inducers of Ca2+-mobilization and inhibitors of oxytocin-induced Ca2+-mobilization. The assay exhibited robust screening statistics (Z´ = 0.73), DMSO-tolerance, and was validated for high-throughput screening against 2,727 small molecules from the Spectrum, NIH Clinical I and II collections of well-annotated compounds. The screen revealed a hit-rate of 1.80% for agonist and 1.39% for antagonist compounds. Concentration-dependent responses of hit-compounds demonstrated an EC50 less than 10μM for 21 hit-antagonist compounds, compared to only 7 hit-agonist compounds. Subsequent studies focused on hit-antagonist compounds. Based on the percent inhibition and functional annotation analyses, we selected 4 confirmed hit-antagonist compounds (benzbromarone, dipyridamole, fenoterol hydrobromide and nisoldipine) for further analysis. Using an ex vivo isometric contractility assay, each compound significantly inhibited uterine contractility, at different potencies (IC50). Overall, these results demonstrate for the first time that high-throughput small-molecules screening of myometrial Ca2+-mobilization is an ideal primary approach for discovering modulators of uterine contractility. PMID:26600013

  9. EEG spectral power in phasic and tonic REM sleep: different patterns in young adults and children.

    PubMed

    Simor, Péter; Gombos, Ferenc; Szakadát, Sára; Sándor, Piroska; Bódizs, Róbert

    2016-06-01

    Rapid eye movement sleep is composed of phasic and tonic periods, two distinguishable microstates in terms of arousal thresholds and sensory processing. Background electroencephalogram oscillations are also different between periods with (phasic state) and periods without (tonic state) eye movements. In Study 1, previous findings analysing electroencephalogram spectral power in phasic and tonic rapid eye movement sleep were replicated, and analyses extended to the high gamma range (52-90 Hz). In Study 2, phasic and tonic spectral power differences within a group of 4-8-year-old children were examined. Based on the polysomnographic data of 20 young adults, the phasic state yielded increased delta and theta power in anterior sites, as well as generally decreased high alpha and beta power in comparison to the tonic state. Moreover, phasic periods exhibited greater spectral power in the lower and the higher gamma band. Interestingly, children (n = 18) exhibited a different pattern, showing increased activity in the low alpha range during phasic periods. Moreover, during phasic in contrast to tonic rapid eye movement sleep, increased low and high gamma and enhanced low gamma band power emerged in anterior and posterior regions, respectively. The current findings show that spectral activity within the high gamma range substantially contributes to the differences between phasic and tonic rapid eye movement sleep, especially in adults. Moreover, the current data underscore the heterogeneity of rapid eye movement sleep, and point to marked differences between young adults and children regarding phasic/tonic electroencephalogram spectral power. These results suggest that the differentiation between phasic and tonic rapid eye movement periods undergoes maturation. PMID:26762188

  10. EEG spectral power in phasic and tonic REM sleep: different patterns in young adults and children.

    PubMed

    Simor, Péter; Gombos, Ferenc; Szakadát, Sára; Sándor, Piroska; Bódizs, Róbert

    2016-06-01

    Rapid eye movement sleep is composed of phasic and tonic periods, two distinguishable microstates in terms of arousal thresholds and sensory processing. Background electroencephalogram oscillations are also different between periods with (phasic state) and periods without (tonic state) eye movements. In Study 1, previous findings analysing electroencephalogram spectral power in phasic and tonic rapid eye movement sleep were replicated, and analyses extended to the high gamma range (52-90 Hz). In Study 2, phasic and tonic spectral power differences within a group of 4-8-year-old children were examined. Based on the polysomnographic data of 20 young adults, the phasic state yielded increased delta and theta power in anterior sites, as well as generally decreased high alpha and beta power in comparison to the tonic state. Moreover, phasic periods exhibited greater spectral power in the lower and the higher gamma band. Interestingly, children (n = 18) exhibited a different pattern, showing increased activity in the low alpha range during phasic periods. Moreover, during phasic in contrast to tonic rapid eye movement sleep, increased low and high gamma and enhanced low gamma band power emerged in anterior and posterior regions, respectively. The current findings show that spectral activity within the high gamma range substantially contributes to the differences between phasic and tonic rapid eye movement sleep, especially in adults. Moreover, the current data underscore the heterogeneity of rapid eye movement sleep, and point to marked differences between young adults and children regarding phasic/tonic electroencephalogram spectral power. These results suggest that the differentiation between phasic and tonic rapid eye movement periods undergoes maturation.

  11. Advances in studying phasic dopamine signaling in brain reward mechanisms

    PubMed Central

    Wickham, Robert J.; Solecki, Wojciech; Rathbun, Liza R.; Neugebauer, Nichole M.; Wightman, R. Mark; Addy, Nii A.

    2013-01-01

    The last sixty years of research have provided extraordinary advances of our knowledge of the reward system. Since its initial discovery as a neurotransmitter by Carlsson and colleagues (Carlsson et al., 1957), dopamine (DA) has emerged as an important mediator of reward processing. As a result, a number of electrochemical techniques have been developed to directly measure DA levels in the brain using various preparations. Many of these techniques and preparations differ in the types of questions that they can address. Together, these techniques have begun to elucidate the complex roles of tonic and phasic DA signaling in reward processing and in addiction. In this review, we will first provide a guide for the most commonly used electrochemical methods for DA detection and describe their utility in furthering our knowledge about DA's role in reward and addiction. Second, we will review the value of common in vitro and in vivo preparations and describe their ability to address different types of questions. Last, we will review recent data that has provided new insight of the mechanisms of in vivo phasic DA signaling and its role in reward processing and reward-mediated behavior. PMID:23747914

  12. Control of Phasic Firing by a Background Leak Current in Avian Forebrain Auditory Neurons

    PubMed Central

    Dagostin, André A.; Lovell, Peter V.; Hilscher, Markus M.; Mello, Claudio V.; Leão, Ricardo M.

    2015-01-01

    Central neurons express a variety of neuronal types and ion channels that promote firing heterogeneity among their distinct neuronal populations. Action potential (AP) phasic firing, produced by low-threshold voltage-activated potassium currents (VAKCs), is commonly observed in mammalian brainstem neurons involved in the processing of temporal properties of the acoustic information. The avian caudomedial nidopallium (NCM) is an auditory area analogous to portions of the mammalian auditory cortex that is involved in the perceptual discrimination and memorization of birdsong and shows complex responses to auditory stimuli We performed in vitro whole-cell patch-clamp recordings in brain slices from adult zebra finches (Taeniopygia guttata) and observed that half of NCM neurons fire APs phasically in response to membrane depolarizations, while the rest fire transiently or tonically. Phasic neurons fired APs faster and with more temporal precision than tonic and transient neurons. These neurons had similar membrane resting potentials, but phasic neurons had lower membrane input resistance and time constant. Surprisingly phasic neurons did not express low-threshold VAKCs, which curtailed firing in phasic mammalian brainstem neurons, having similar VAKCs to other NCM neurons. The phasic firing was determined not by VAKCs, but by the potassium background leak conductances, which was more prominently expressed in phasic neurons, a result corroborated by pharmacological, dynamic-clamp, and modeling experiments. These results reveal a new role for leak currents in generating firing diversity in central neurons. PMID:26696830

  13. Oxytocin-stimulated responses in a pregnant human immortalized myometrial cell line.

    PubMed

    Monga, M; Ku, C Y; Dodge, K; Sanborn, B M

    1996-08-01

    Smooth muscle cells isolated from the myometrium of a pregnant woman at term were infected with a replication-defective adenovirus vector expressing the E6/E7 proteins of human papilloma virus 16. A clonal line, PHM1-41, was selected by resistance to Geneticin and examined for maintenance of smooth muscle phenotype and response to oxytocin. The immortalized cell line retained morphological characteristics of proliferating smooth muscle cells in culture for up to 22 passages and has been used for over 2 years. The cells expressed smooth muscle-specific alpha-actin and retained estrogen receptors. Oxytocin receptors were present, as measured by whole cell binding assay using the oxytocin antagonist 125I-d(CH2)5[Tyr-(Me)2,Thr4,-Orn8,Tyr9-NH2] as ligand and oxytocin as competitor. The data were best described by a one-site binding model, with a Kd of 0.36 nM and a binding site concentration of 37 fmol/microgram DNA. PHM1-41 cells responded to oxytocin with an increase in intracellular free calcium (EC50 15 nM) and an increase in phosphatidylinositol turnover. Oxytocin-stimulated phosphatidylinositol turnover was inhibited by preincubation with the cAMP analog CPT-cAMP. This immortalized myometrial cell line should prove useful for studies relating to human myometrial function. PMID:8828850

  14. Immune Aspects and Myometrial Actions of Progesterone and CRH in Labor

    PubMed Central

    Vrachnis, Nikolaos; Malamas, Fotodotis M.; Sifakis, Stavros; Tsikouras, Panayiotis; Iliodromiti, Zoe

    2012-01-01

    Progesterone and corticotropin-releasing hormone (CRH) have a critical role in pregnancy and labor, as changes related to these hormones are crucial for the transition from myometrial quiescence to contractility. The mechanisms related to their effect differ between humans and other species, thus, despite extensive research, many questions remain to be answered regarding their mediation in human labor. Immune responses to progesterone and CRH are important for labor. Progesterone acts as an immunomodulator which controls many immune actions during pregnancy, and its withdrawal releases the inhibitory action on inflammatory pathways. In humans, a “functional” progesterone withdrawal occurs with onset of labor through changes in progesterone metabolism, progesterone receptors, and other molecules that either facilitate or antagonize progesterone function. Placental CRH acts on the fetal pituitary-adrenal axis to stimulate adrenal production of androgens and cortisol and also acts directly on myometrial cells via its receptors. CRH also affects inflammatory signals and vice versa. Interactions between progesterone and CRH additionally occur during labor. We describe the role of these two hormones in human myometrium and their interactions with the immune system during labor. PMID:22028729

  15. Dexamethasone effects on ritodrine-induced changes in myometrial contractility and beta-adrenergic receptor function.

    PubMed

    Ward, S M; Caritis, S N; Chiao, J P; Moore, J J

    1988-12-01

    We have previously demonstrated in pregnant sheep that ritodrine infusion for 24 hours reduces myometrial beta-adrenergic receptor density and isoproterenol-stimulated adenylate cyclase activity. These receptor-associated changes were accompanied by an increasing inability of ritodrine to inhibit uterine contractility induced by a bolus of oxytocin. In the present study, we evaluated whether these ritodrine-induced effects could be altered by dexamethasone. Ten pregnant sheep at gestational ages of 92 to 130 days received ritodrine 2 micrograms/kg/min for 24 hours. Five animals also received dexamethasone 10 mg intravascularly twice during the ritodrine infusion. Before and at 4 and 24 hours of ritodrine infusion, the animals were given an identical dose of oxytocin as a bolus, and the area under the uterine pressure-time curve was quantified. Myometrial biopsy specimens were obtained before and after ritodrine infusion. Dexamethasone treatment prevented ritodrine-induced reductions in beta-adrenergic receptor density and isoproterenol-stimulated adenylate cyclase activity. Despite these receptor-associated effects, dexamethasone did not prevent the loss of tocolytic efficacy associated with prolonged ritodrine infusion.

  16. Oscillatory Motion of a Bi-Phasic Slug in a Teflon Reactor

    NASA Astrophysics Data System (ADS)

    Abolhasani, Milad; Jensen, Klavs

    2015-11-01

    Bi-phasic physical/chemical processes require transfer of solute/reagent molecules across the interface. Continuous multi-phase flow approaches (using gas as the continuous phase), usually fail in providing sufficient interfacial area for transfer of molecules between the aqueous and organic phases. In continuous segmented flow platforms (with a fluorinated polymer-based reactor), the higher surface tension of the aqueous phase compared to the organic phase of a bi-phasic slug, in combination with the low surface energy of the reactor wall result in a more facile motion of the aqueous phase. Thus, upon applying a pressure gradient across the bi-phasic slug, the aqueous phase of the slug moves through the organic phase and leads the bi-phasic slug, thereby limiting the available interfacial area for the bi-phasic mass transfer only to the semi-spherical interface between the two phases. Disrupting the quasi-equilibrium state of the bi-phasic slug through reversing the pressure gradient across the bi-phasic slug causes the aqueous phase to move back through the organic phase. In this work, we experimentally investigate the dynamics of periodic alteration of the pressure gradient across a bi-phasic slug, and characterize the resulting enhanced interfacial area on the bi-phasic mass transfer rate. We demonstrate the enhanced mass transfer rate of the oscillatory flow strategy compared to the continuous multi-phase approach using bi-phasic Pd catalyzed carbon-carbon and carbon-nitrogen cross coupling reactions. NSERC Postdoctoral Fellowship, Novartis Center for Continuous Manufacturing.

  17. Electrosensory optimization to conspecific phasic signals for mating.

    PubMed

    Tricas, T C; Michael, S W; Sisneros, J A

    1995-12-29

    Ampullary electroreceptor systems in fishes and aquatic amphibians are known to function in prey localization by the movement of the animal through a weak dc field produced by their prey. The round stingray produces an electric field with a complex geometry that is modulated rhythmically by movements of the spiracles and gill slits during ventilation. This weak stimulus is used in the field by reproductively active male stingrays to locate mates, and also by female rays to locate buried consexuals. Electrosensory primary afferent neurons are most sensitive to stimuli that vary sinusoidally at the same frequency as the natural respiratory movements. The match between primary afferent frequency sensitivity and the ventilatory phasic signals produced by conspecifics indicates that the electrosensory system serves an important biological function in the social behavior of elasmobranchs. PMID:8787848

  18. A nonlinear model of the phasic dynamics of muscle activation

    NASA Technical Reports Server (NTRS)

    Hannaford, Blake

    1990-01-01

    A phasic excitation-activation (PEXA) model is presented of the process of motoneuron excitation and the resultant activation and force development of a motor unit. The model input is an amount of depolarizing current (as when injected with an intracellular electrode), and the model output is muscle force. The model includes dynamics and nonlinearities similar to phenomena discovered experimentally by others: the firing rate response of motoneurons to steps of depolarizing current and the catch-like enhancement of force produced by overlapping motor neuron action potentials. The parameter values used in this model are derived from experimentally measured data and are expressed in physical units. Model predictions extend to published data beyond those used in generating the model parameter values.

  19. Up-regulation of guinea pig myometrial beta-adrenergic receptors by intrauterine estradiol and progesterone pellets.

    PubMed

    Hatjis, C G; Koritnik, D R; Grogan, D M

    1989-03-01

    The effect of intrauterine implantation of 17 beta-estradiol and progesterone on the concentration and affinity of myometrial beta-adrenergic receptor were studied in nonpregnant, previously oophorectomized guinea pigs receiving intrauterine implants of either 17 beta-estradiol, progesterone, a combination of the two hormones, or placebo for 7 days. Myometrial beta-adrenergic receptors were characterized by use of (-)-iodine 125-cyanopindolol as the specific beta-adrenergic receptor ligand. On comparison with the control group, administration of 17 beta-estradiol or progesterone resulted in a severalfold increase in the concentration (Bmax) of myometrial beta-adrenergic receptor and a lesser but significant increase in the dissociation constant, KD. Although a combination of 17 beta-estradiol and progesterone treatment increased the concentration and the dissociation constant of beta-adrenergic receptors, it did not result in any synergistic or additive effect. We conclude that intrauterine administration of these sex steroid hormones, directly or indirectly, modulates myometrial beta-adrenergic receptor concentrations and affinity.

  20. Juice of Bryophyllum pinnatum (Lam.) inhibits oxytocin-induced increase of the intracellular calcium concentration in human myometrial cells.

    PubMed

    Simões-Wüst, A P; Grãos, M; Duarte, C B; Brenneisen, R; Hamburger, M; Mennet, M; Ramos, M H; Schnelle, M; Wächter, R; Worel, A M; von Mandach, U

    2010-10-01

    The use of preparations from Bryophyllum pinnatum in tocolysis is supported by both clinical (retrospective comparative studies) and experimental (using uterus strips) evidence. We studied here the effect of B. pinnatum juice on the response of cultured human myometrial cells to stimulation by oxytocin, a hormone known to be involved in the control of uterine contractions by increasing the intracellular free calcium concentration ([Ca2+]i). In this work, [Ca2+]i was measured online during stimulation of human myometrial cells (hTERT-C3 and M11) with oxytocin, which had been pre-incubated in the absence or in the presence of B. pinnatum juice. Since no functional voltage-gated Ca2+ channels could be detected in these myometrial cells, the effect of B. pinnatum juice was as well studied in SH-SY5Y neuroblastoma cells, which are known to have such channels and can be depolarised with KCl. B. pinnatum juice prevented the oxytocin-induced increase in [Ca2+]i in hTERT-C3 human myometrial cells in a dose-dependent manner, achieving a ca. 80% inhibition at a 2% concentration. Comparable results were obtained with M11 human primary myometrial cells. In hTERT-C3 cells, prevention of the oxytocin-induced increase in [Ca2+]i was independent of the extracellular Ca2+ concentration and of voltage-dependent Ca2+-channels. B. pinnatum juice delayed, but did not prevent the depolarization-induced increase in [Ca2+]i in SH-SY5Y cells. Taken together, the data suggest a specific and concentration-dependent effect of B. pinnatum juice on the oxytocin signalling pathway, which seems to corroborate its use in tocolysis. Such a specific mechanism would explain the rare and minor side-effects in tocolysis with B. pinnatum as well as its high therapeutic index. PMID:20381326

  1. Phasic bursting activity of rat paraventricular neurones in the absence of synaptic transmission.

    PubMed

    Hatton, G I

    1982-06-01

    1. The purpose of this study was to determine whether the phasic bursting activity, characteristic of certain magnocellular neuropeptidergic neurones in rat hypothalamus, is dependent upon chemical synaptic input.2. Slices of hypothalamus were placed in an in vitro chamber with hippocampal slices. The synaptic response in the CA1 cell layer from Schaffer collateral stimulation was monitored before, during and after synaptic transmission was blocked by superfusion of medium containing high Mg(2+) (either 18.7 or 9.3 mM) and low Ca(2+) (0.05 mM). This well studied pathway was chosen as an assay of synaptic blockade because hypothalamic circuitry is relatively unknown.3. The electrical activity of twenty-two phasic bursting neurones in the lateral portion of the paraventricular nucleus (p.v.n.) was recorded. Nineteen of twenty-two phasic p.v.n. neurones were recorded only after synaptic transmission was blocked. The remaining three cells were firing phasically in standard medium when first encountered and continued to display phasic bursting activity for up to 1.25 hr after synaptic blockade. Active cells in nearby hypothalamic areas did not show phasic bursting patterns either before or after synaptic transmission was blocked.4. The phasic bursting activity of the p.v.n. neurones in this study and that of previously reported p.v.n. cells in vivo were similar in (a) firing rate within bursts (b) burst length and (c) silent period duration.5. It is concluded that phasic bursting in p.v.n. magnocellular neuropeptidergic cells is not dependent upon synaptically mediated excitation or recurrent inhibition as has been hypothesized earlier.6. Alternative hypotheses, based upon acute changes in [K(+)](o), endogenous membrane currents and electrotonic coupling are discussed as possible explanations of phasic bursting in these magnocellular neuropeptidergic cells.

  2. Multiple sup 3 H-oxytocin binding sites in rat myometrial plasma membranes

    SciTech Connect

    Crankshaw, D.; Gaspar, V.; Pliska, V. )

    1990-01-01

    The affinity spectrum method has been used to analyse binding isotherms for {sup 3}H-oxytocin to rat myometrial plasma membranes. Three populations of binding sites with dissociation constants (Kd) of 0.6-1.5 x 10(-9), 0.4-1.0 x 10(-7) and 7 x 10(-6) mol/l were identified and their existence verified by cluster analysis based on similarities between Kd, binding capacity and Hill coefficient. When experimental values were compared to theoretical curves constructed using the estimated binding parameters, good fits were obtained. Binding parameters obtained by this method were not influenced by the presence of GTP gamma S (guanosine-5'-O-3-thiotriphosphate) in the incubation medium. The binding parameters agree reasonably well with those found in uterine cells, they support the existence of a medium affinity site and may allow for an explanation of some of the discrepancies between binding and response in this system.

  3. Myometrial relaxation of mice via expression of two pore domain acid sensitive K(+) (TASK-2) channels.

    PubMed

    Kyeong, Kyu-Sang; Hong, Seung Hwa; Kim, Young Chul; Cho, Woong; Myung, Sun Chul; Lee, Moo Yeol; You, Ra Young; Kim, Chan Hyung; Kwon, So Yeon; Suzuki, Hikaru; Park, Yeon Jin; Jeong, Eun-Hwan; Kim, Hak Soon; Kim, Heon; Lim, Seung Woon; Xu, Wen-Xie; Lee, Sang Jin; Ji, Il Woon

    2016-09-01

    Myometrial relaxation of mouse via expression of two-pore domain acid sensitive (TASK) channels was studied. In our previous report, we suggested that two-pore domain acid-sensing K(+) channels (TASK-2) might be one of the candidates for the regulation of uterine circular smooth muscles in mice. In this study, we tried to show the mechanisms of relaxation via TASK-2 channels in marine myometrium. Isometric contraction measurements and patch clamp technique were used to verify TASK conductance in murine myometrium. Western blot and immunehistochemical study under confocal microscopy were used to investigate molecular identity of TASK channel. In this study, we showed that TEA and 4-AP insensitive non-inactivating outward K(+) current (NIOK) may be responsible for the quiescence of murine pregnant longitudinal myometrium. The characteristics of NIOK coincided with two-pore domain acid-sensing K(+) channels (TASK-2). NIOK in the presence of K(+) channel blockers was inhibited further by TASK inhibitors such as quinidine, bupivacaine, lidocaine, and extracellular acidosis. Furthermore, oxytocin and estrogen inhibited NIOK in pregnant myometrium. When compared to non-pregnant myometrium, pregnant myometrium showed stronger inhibition of NIOK by quinidine and increased immunohistochemical expression of TASK-2. Finally, TASK-2 inhibitors induced strong myometrial contraction even in the presence of L-methionine, a known inhibitor of stretch-activated channels in the longitudinal myometrium of mouse. Activation of TASK-2 channels seems to play an essential role for relaxing uterus during pregnancy and it might be one of the alternatives for preventing preterm delivery.

  4. Myometrial relaxation of mice via expression of two pore domain acid sensitive K+ (TASK-2) channels

    PubMed Central

    Kyeong, Kyu-Sang; Hong, Seung Hwa; Cho, Woong; Myung, Sun Chul; Lee, Moo Yeol; You, Ra Young; Kim, Chan Hyung; Kwon, So Yeon; Suzuki, Hikaru; Park, Yeon Jin; Jeong, Eun-Hwan; Kim, Hak Soon; Kim, Heon; Lim, Seung Woon; Xu, Wen-Xie; Lee, Sang Jin

    2016-01-01

    Myometrial relaxation of mouse via expression of two-pore domain acid sensitive (TASK) channels was studied. In our previous report, we suggested that two-pore domain acid-sensing K+ channels (TASK-2) might be one of the candidates for the regulation of uterine circular smooth muscles in mice. In this study, we tried to show the mechanisms of relaxation via TASK-2 channels in marine myometrium. Isometric contraction measurements and patch clamp technique were used to verify TASK conductance in murine myometrium. Western blot and immunehistochemical study under confocal microscopy were used to investigate molecular identity of TASK channel. In this study, we showed that TEA and 4-AP insensitive non-inactivating outward K+ current (NIOK) may be responsible for the quiescence of murine pregnant longitudinal myometrium. The characteristics of NIOK coincided with two-pore domain acid-sensing K+ channels (TASK-2). NIOK in the presence of K+ channel blockers was inhibited further by TASK inhibitors such as quinidine, bupivacaine, lidocaine, and extracellular acidosis. Furthermore, oxytocin and estrogen inhibited NIOK in pregnant myometrium. When compared to non-pregnant myometrium, pregnant myometrium showed stronger inhibition of NIOK by quinidine and increased immunohistochemical expression of TASK-2. Finally, TASK-2 inhibitors induced strong myometrial contraction even in the presence of L-methionine, a known inhibitor of stretch-activated channels in the longitudinal myometrium of mouse. Activation of TASK-2 channels seems to play an essential role for relaxing uterus during pregnancy and it might be one of the alternatives for preventing preterm delivery. PMID:27610042

  5. Myometrial relaxation of mice via expression of two pore domain acid sensitive K(+) (TASK-2) channels.

    PubMed

    Kyeong, Kyu-Sang; Hong, Seung Hwa; Kim, Young Chul; Cho, Woong; Myung, Sun Chul; Lee, Moo Yeol; You, Ra Young; Kim, Chan Hyung; Kwon, So Yeon; Suzuki, Hikaru; Park, Yeon Jin; Jeong, Eun-Hwan; Kim, Hak Soon; Kim, Heon; Lim, Seung Woon; Xu, Wen-Xie; Lee, Sang Jin; Ji, Il Woon

    2016-09-01

    Myometrial relaxation of mouse via expression of two-pore domain acid sensitive (TASK) channels was studied. In our previous report, we suggested that two-pore domain acid-sensing K(+) channels (TASK-2) might be one of the candidates for the regulation of uterine circular smooth muscles in mice. In this study, we tried to show the mechanisms of relaxation via TASK-2 channels in marine myometrium. Isometric contraction measurements and patch clamp technique were used to verify TASK conductance in murine myometrium. Western blot and immunehistochemical study under confocal microscopy were used to investigate molecular identity of TASK channel. In this study, we showed that TEA and 4-AP insensitive non-inactivating outward K(+) current (NIOK) may be responsible for the quiescence of murine pregnant longitudinal myometrium. The characteristics of NIOK coincided with two-pore domain acid-sensing K(+) channels (TASK-2). NIOK in the presence of K(+) channel blockers was inhibited further by TASK inhibitors such as quinidine, bupivacaine, lidocaine, and extracellular acidosis. Furthermore, oxytocin and estrogen inhibited NIOK in pregnant myometrium. When compared to non-pregnant myometrium, pregnant myometrium showed stronger inhibition of NIOK by quinidine and increased immunohistochemical expression of TASK-2. Finally, TASK-2 inhibitors induced strong myometrial contraction even in the presence of L-methionine, a known inhibitor of stretch-activated channels in the longitudinal myometrium of mouse. Activation of TASK-2 channels seems to play an essential role for relaxing uterus during pregnancy and it might be one of the alternatives for preventing preterm delivery. PMID:27610042

  6. Myometrial relaxation of mice via expression of two pore domain acid sensitive K+ (TASK-2) channels

    PubMed Central

    Kyeong, Kyu-Sang; Hong, Seung Hwa; Cho, Woong; Myung, Sun Chul; Lee, Moo Yeol; You, Ra Young; Kim, Chan Hyung; Kwon, So Yeon; Suzuki, Hikaru; Park, Yeon Jin; Jeong, Eun-Hwan; Kim, Hak Soon; Kim, Heon; Lim, Seung Woon; Xu, Wen-Xie; Lee, Sang Jin

    2016-01-01

    Myometrial relaxation of mouse via expression of two-pore domain acid sensitive (TASK) channels was studied. In our previous report, we suggested that two-pore domain acid-sensing K+ channels (TASK-2) might be one of the candidates for the regulation of uterine circular smooth muscles in mice. In this study, we tried to show the mechanisms of relaxation via TASK-2 channels in marine myometrium. Isometric contraction measurements and patch clamp technique were used to verify TASK conductance in murine myometrium. Western blot and immunehistochemical study under confocal microscopy were used to investigate molecular identity of TASK channel. In this study, we showed that TEA and 4-AP insensitive non-inactivating outward K+ current (NIOK) may be responsible for the quiescence of murine pregnant longitudinal myometrium. The characteristics of NIOK coincided with two-pore domain acid-sensing K+ channels (TASK-2). NIOK in the presence of K+ channel blockers was inhibited further by TASK inhibitors such as quinidine, bupivacaine, lidocaine, and extracellular acidosis. Furthermore, oxytocin and estrogen inhibited NIOK in pregnant myometrium. When compared to non-pregnant myometrium, pregnant myometrium showed stronger inhibition of NIOK by quinidine and increased immunohistochemical expression of TASK-2. Finally, TASK-2 inhibitors induced strong myometrial contraction even in the presence of L-methionine, a known inhibitor of stretch-activated channels in the longitudinal myometrium of mouse. Activation of TASK-2 channels seems to play an essential role for relaxing uterus during pregnancy and it might be one of the alternatives for preventing preterm delivery.

  7. Phasic Dopamine Modifies Sensory-Driven Output of Striatal Neurons through Synaptic Plasticity.

    PubMed

    Wieland, Sebastian; Schindler, Sebastian; Huber, Cathrin; Köhr, Georg; Oswald, Manfred J; Kelsch, Wolfgang

    2015-07-01

    Animals are facing a complex sensory world in which only few stimuli are relevant to guide behavior. Value has to be assigned to relevant stimuli such as odors to select them over concurring information. Phasic dopamine is involved in the value assignment to stimuli in the ventral striatum. The underlying cellular mechanisms are incompletely understood. In striatal projection neurons of the ventral striatum in adult mice, we therefore examined the features and dynamics of phasic dopamine-induced synaptic plasticity and how this plasticity may modify the striatal output. Phasic dopamine is predicted to tag inputs that occur in temporal proximity. Indeed, we observed D1 receptor-dependent synaptic potentiation only when odor-like bursts and optogenetically evoked phasic dopamine release were paired within a time window of <1 s. Compatible with predictions of dynamic value assignment, the synaptic potentiation persisted after the phasic dopamine signal had ceased, but gradually reversed when odor-like bursts continued to be presented. The synaptic plasticity depended on the sensory input rate and was input specific. Importantly, synaptic plasticity amplified the firing response to a given olfactory input as the dendritic integration and the firing threshold remained unchanged during synaptic potentiation. Thus, phasic dopamine-induced synaptic plasticity can change information transfer through dynamic increases of the output of striatal projection neurons to specific sensory inputs. This plasticity may provide a neural substrate for dynamic value assignment in the striatum.

  8. Effects of antiprogestogen (RU-486) treatment on myometrial and cervical alpha and beta-adrenoceptors in pregnant rabbits.

    PubMed

    Falkay, G

    1990-11-01

    Oestrogen and progesterone influence myometrial and cervical responses at different levels of the mechanisms regulating uterine contractility. One of these mechanisms could involve alterations in the adrenoceptor concentrations. This study was undertaken to assess the effects of treatment with the antiprogestogen RU-486 on the concentrations of alpha- and beta-adrenoceptors in pregnant rabbit myometrial and cervical membranes by means of a radioligand binding technique. The probable relative oestrogen dominance due to the antiprogestogen treatment selectively decreased the alpha 2-adrenoceptor subtype in the cervix, where an alpha-adrenoceptor dominance was found on day 27 of pregnancy. The results indicate a heterologous regulation of alpha-adrenoceptors by sex steroids, i.e. suppression of the alpha 2-adrenoceptor concentration by antiprogestogen treatment.

  9. Isolation and partial cloning of ryanodine-sensitive Ca2+ release channel protein isoforms from human myometrial smooth muscle.

    PubMed

    Lynn, S; Morgan, J M; Lamb, H K; Meissner, G; Gillespie, J I

    1995-09-18

    Partial cDNAs of the ryanodine receptor were cloned using PCR analysis from reverse transcribed total and mRNA, extracted from freshly isolated pregnant, non-pregnant, and cultured human myometrial smooth muscle. The identity of these clones was confirmed by nucleotide sequencing of the fragments and indicate the expression of both the skeletal and brain ryanodine receptor isoforms in these preparations. In freshly isolated non-pregnant myometrial tissue, membrane fractions displaying specific [3H]ryanodine binding activities were isolated using density gradient centrifugation. SDS-PAGE of the sucrose gradient fractions indicated the specific comigration of a polypeptide with a molecular mass of approximately 544 kDa with the ryanodine binding activity.

  10. Maternal age effects on myometrial expression of contractile proteins, uterine gene expression, and contractile activity during labor in the rat

    PubMed Central

    Elmes, Matthew; Szyszka, Alexandra; Pauliat, Caroline; Clifford, Bethan; Daniel, Zoe; Cheng, Zhangrui; Wathes, Claire; McMullen, Sarah

    2015-01-01

    Advanced maternal age of first time pregnant mothers is associated with prolonged and dysfunctional labor and significant risk of emergency cesarean section. We investigated the influence of maternal age on myometrial contractility, expression of contractile associated proteins (CAPs), and global gene expression in the parturient uterus. Female Wistar rats either 8 (YOUNG n = 10) or 24 (OLDER n = 10) weeks old were fed laboratory chow, mated, and killed during parturition. Myometrial strips were dissected to determine contractile activity, cholesterol (CHOL) and triglycerides (TAG) content, protein expression of connexin-43 (GJA1), prostaglandin-endoperoxide synthase 2 (PTGS2), and caveolin 1 (CAV-1). Maternal plasma concentrations of prostaglandins PGE2, PGF2α, and progesterone were determined by RIA. Global gene expression in uterine samples was compared using Affymetrix Genechip Gene 2.0 ST arrays and Ingenuity Pathway analysis (IPA). Spontaneous contractility in myometrium exhibited by YOUNG rats was threefold greater than OLDER animals (P < 0.027) but maternal age had no significant effect on myometrial CAP expression, lipid profiles, or pregnancy-related hormones. OLDER myometrium increased contractile activity in response to PGF2α, phenylephrine, and carbachol, a response absent in YOUNG rats (all P < 0.002). Microarray analysis identified that maternal age affected expression of genes related to immune and inflammatory responses, lipid transport and metabolism, steroid metabolism, tissue remodeling, and smooth muscle contraction. In conclusion YOUNG laboring rat myometrium seems primed to contract maximally, whereas activity is blunted in OLDER animals and requires stimulation to meet contractile potential. Further work investigating maternal age effects on myometrial function is required with focus on lipid metabolism and inflammatory pathways. PMID:25876907

  11. Pregnancy-induced changes in the interaction of guinea pig myometrial beta-adrenergic receptors with l-isoproterenol.

    PubMed

    Hatjis, C G; Grogan, D M

    1989-12-01

    The ability of myometrial beta-adrenergic receptors to form a "'high-affinity state" with beta-adrenergic receptor agonists might be greater in pregnant guinea pigs at greater than or equal to 0.9 of gestation than in nonpregnant animals. To determine whether this difference is due to pregnancy in general or is associated only with late pregnancy and to determine whether it persists in the postpartum period, we studied the interaction of l-isoproterenol with beta-adrenergic receptors in myometrial membranes obtained from nonpregnant (nulligravid) animals, pregnant (primigravid) animals at 0.3, 0.7, and 0.9 to 1.0 of gestation (term 65 days), and postpartum guinea pigs (2 to 3 days). The affinity of myometrial beta-adrenergic receptors for l-isoproterenol was measured by percent inhibition of -[125I]cyanopindolol binding. In the presence of magnesium chloride, the competition curves could be resolved into two affinity state of the beta-adrenergic receptor, "high" and "low," respectively, in all groups. The ratio of the dissociation constant of the "low"-affinity state to that of the "high"-affinity state was significantly higher in pregnant guinea pigs at greater than or equal to 0.9 of gestation than in nonpregnant or postpartum animals and in pregnant animals of earlier gestations. In the presence of guanosine triphosphate only one (low-affinity) state of the receptor was detectable. Thus it is only in pregnant guinea pigs at greater than or equal to 0.9 of gestation that the ability of myometrial beta-adrenergic receptors to form a high-affinity state is enhanced.

  12. Mammalian target of rapamycin is activated in association with myometrial proliferation during pregnancy.

    PubMed

    Jaffer, Shabana; Shynlova, Oksana; Lye, Stephen

    2009-10-01

    The adaptive growth of the uterus during gestation involves gradual changes in cellular phenotypes from the early proliferative to the intermediate synthetic phase of cellular hypertrophy, ending in the final contractile/labour phenotype. The mammalian target of rapamycin (mTOR) signaling pathway regulates cell growth and proliferation in many tissues. We hypothesized that mTOR was a mediator of hormone-initiated myometrial hyperplasia during gestation. The protein expression and phosphorylation levels of mTOR, its upstream regulators [insulin receptor substrate-1, phosphoinositide-3-kinase (PI3K), Akt], and downstream effectors [S6-kinase-1 (S6K1) and eI4FE-binding protein 1 (4EBP1)] were analyzed throughout normal pregnancy in rats. In addition, we used an ovariectomized (OVX) rat model to analyze the modulation of the mTOR pathway and proliferative activity of the uterine myocytes by estradiol alone and in combination with the mTOR-specific inhibitor rapamycin. Our results demonstrate that insulin receptor substrate-1 protein levels and the phosphorylated (activated) forms of PI3K, mTOR, and S6K1 were significantly up-regulated in the rat myometrium during the proliferative phase of pregnancy. Treatment of the OVX rats with estradiol caused a transient increase in IGF-I followed by an up-regulation of the PI3K/mTOR pathway, which became apparent by a cascade of phosphorylation reactions (P-P85, P-Akt, P-mTOR, P-S6K1, and P-4EBP1). Rapamycin blocked activation of P-mTOR, P-S6K1, and P-4EBP1 proteins and significantly reduced the number of proliferating cells in the myometrium of OVX rats. Our in vivo data demonstrate that estradiol was able to activate the PI3K/mTOR signaling pathway in uterine myocytes and suggest that this activation is responsible for the induction of myometrial hyperplasia during early gestation.

  13. Successful treatment of a persistent mole with myometrial invasion by direct injection of methotrexate.

    PubMed

    Su, W H; Wang, P H; Chang, S P

    2001-01-01

    For patients with persistent or invasive gestational trophoblastic disease (GTD), systemic injection of chemotherapy is the treatment of choice if fertility is to be preserved. To prevent serious adverse effects after systemic use and possibly achieve better effects, direct local injection of chemotherapy into the tumor site, especially when in the myometrium, seems a reasonable alternative. A patient with a persistent molar pregnancy with myometrial invasion is presented. A plateau of beta-hCG (human chorionic gonadotropin) level around 550 mIU/mL was noticed for three weeks though systemic methotrexate (MTX) injection and repeat suction curettage had been performed. During the same period, a well-defined invasive complex with multiple vesicles in the myometrium was documented using transvaginal ultrasound (TVUS). Sonar-guided injection to the tumor using 50 mg MTX was performed uneventfully. An obvious shrinkage of the mass and declining beta-hCG level were demonstrated after the procedure. The patient restored her menses after the operation and a fertility evaluation including serial beta-hCG levels and hysterosalpingography showed them to be within the reference ranges. The successful outcome of this case encouraged us to treat localized invasive GTD using direct injection of MTX with the guidance of TVUS. Since no identical cases were found in our review of the English literature, more cases and similar regimens are needed to establish the safety and efficacy of this procedure.

  14. Progesterone prevents linkage of rabbit myometrial alpha 2-adrenergic receptors to inhibition of adenylate cyclase.

    PubMed

    Wu, Y Y; Riemer, R K; Goldfien, A; Roberts, J M

    1989-04-01

    The uterine response to adrenergic stimulation is determined by the hormonal milieu. This response is particularly well characterized in the rabbit. In this species, as in humans, the response of the uterus to sympathetic stimulation is alpha-adrenergically mediated contraction with elevated circulating estrogen. However, with progesterone predominance, similar stimulation inhibits uterine contractions, a response mediated by beta-adrenergic receptors acting through their second message, cyclic adenosine monophosphate. We studied the mechanisms by which sex steroids regulate myometrial adrenergic responses. In this study, we questioned whether part of the effect of sex steroids could be explained by an alteration of the coupling of the alpha 2-adrenergic receptor to the inhibition of adenylate cyclase. We found that in the progesterone-treated rabbit, although alpha 2-receptors are present, they are not linked to inhibition of cyclic adenosine monophosphate synthesis. The net synthesis of cyclic adenosine monophosphage in response to endogenous catecholamines is determined by their activation of beta-adrenergic receptors to increase and alpha 2-receptors to decrease cyclic adenosine monophosphate formation. Thus the uncoupling of alpha 2-receptors contributes to increased intracellular cyclic adenosine monophosphate in myometrium of progesterone-treated animals consistent with the reported predominance of beta-adrenergic contractile responses in this setting.

  15. Phasic Motor Activity of Respiratory and Non-Respiratory Muscles in REM Sleep

    PubMed Central

    Fraigne, Jimmy J.; Orem, John M.

    2011-01-01

    Objectives: In this study, we quantified the profiles of phasic activity in respiratory muscles (diaphragm, genioglossus and external intercostal) and non-respiratory muscles (neck and extensor digitorum) across REM sleep. We hypothesized that if there is a unique pontine structure that controls all REM sleep phasic events, the profiles of the phasic twitches of different muscle groups should be identical. Furthermore, we described how respiratory parameters (e.g., frequency, amplitude, and effort) vary across REM sleep to determine if phasic processes affect breathing. Methods: Electrodes were implanted in Wistar rats to record brain activity and muscle activity of neck, extensor digitorum, diaphragm, external intercostal, and genioglossal muscles. Ten rats were studied to obtain 313 REM periods over 73 recording days. Data were analyzed offline and REM sleep activity profiles were built for each muscle. In 6 animals, respiratory frequency, effort, amplitude, and inspiratory peak were also analyzed during 192 REM sleep periods. Results: Respiratory muscle phasic activity increased in the second part of the REM period. For example, genioglossal activity increased in the second part of the REM period by 63.8% compared to the average level during NREM sleep. This profile was consistent between animals and REM periods (η2 = 0.58). This increased activity seen in respiratory muscles appeared as irregular bursts and trains of activity that could affect rythmo-genesis. Indeed, the increased integrated activity seen in the second part of the REM period in the diaphragm was associated with an increase in the number (28.3%) and amplitude (30%) of breaths. Non-respiratory muscle phasic activity in REM sleep did not have a profile like the phasic activity of respiratory muscles. Time in REM sleep did not have an effect on nuchal activity (P = 0.59). Conclusion: We conclude that the concept of a common pontine center controlling all REM phasic events is not supported by our

  16. The adverse effects of aldrin and dieldrin on both myometrial contractions and the secretory functions of bovine ovaries and uterus in vitro.

    PubMed

    Wrobel, Michał H; Grzeszczyk, Marlena; Mlynarczuk, Jaroslaw; Kotwica, Jan

    2015-05-15

    Aldrin and dieldrin are chloroorganic insecticides which are recognised as endocrine disruptors. The aim of the study was to investigate their effect on the secretory functions of the uterus and ovary and on myometrial contractions. Myometrial strips and uterine and ovarian cells from nonpregnant cows were incubated with the xenobiotics (0.1, 1 or 10 ng/ml) for 24 or 72 h. Next, their effect on viability of myometrial, endometrial, granulosa and luteal cells, myometrial strip contractions, the synthesis and secretion of prostaglandins (PGs: PGF2α and PGE2) from uterine cells, the secretion of oestradiol (E2), testosterone (T) and oxytocin (OT) from granulosa cells and the secretion of progesterone (P4) and OT from luteal cells were determined. Neither of the xenobiotics (10 ng/ml) affected (P>0.05) the viability of the ovarian and uterine cells, while both (0.1-10 ng/ml) decreased (P<0.05) the basal and OT-stimulated myometrial contractions. In spite of these effects, neither of the insecticides affected (P>0.05) the synthesis and the secretion of PGs from the myometrial cells. Although they also did not impair the secretion of the PGs from the endometrial cells, they abolished (P<0.05) the stimulatory effect of OT (P<0.05) on the secretion of the PGs and stimulated (P<0.05) the secretion of OT from the granulosa and luteal cells. Moreover, aldrin and dieldrin stimulated secretion of E2 and T from the granulosa cells, while only dieldrin increased (P<0.05) the secretion of P4 from luteal cells. The data show that aldrin and dieldrin stimulated the secretory function of the cultured granulosa and luteal cells and inhibited the myometrial contractions of cows in vitro, which may affect on natural parturition.

  17. Enhanced phasic GABA inhibition during the repair phase of stroke: a novel therapeutic target

    PubMed Central

    Paz, Jeanne T.; Wang, Eric Hou Jen; Badgely, Corrine; Olson, Andrew; Micheva, Kristina D.; Wang, Gordon; Lemmens, Robin; Tran, Kevin V.; Nishiyama, Yasuhiro; Liang, Xibin; Hamilton, Scott A.; O’Rourke, Nancy; Smith, Stephen J.; Huguenard, John R.; Bliss, Tonya M.

    2016-01-01

    Ischaemic stroke is the leading cause of severe long-term disability yet lacks drug therapies that promote the repair phase of recovery. This repair phase of stroke occurs days to months after stroke onset and involves brain remapping and plasticity within the peri-infarct zone. Elucidating mechanisms that promote this plasticity is critical for the development of new therapeutics with a broad treatment window. Inhibiting tonic (extrasynaptic) GABA signalling during the repair phase was reported to enhance functional recovery in mice suggesting that GABA plays an important function in modulating brain repair. While tonic GABA appears to suppress brain repair after stroke, less is known about the role of phasic (synaptic) GABA during the repair phase. We observed an increase in postsynaptic phasic GABA signalling in mice within the peri-infarct cortex specific to layer 5; we found increased numbers of α1 receptor subunit-containing GABAergic synapses detected using array tomography, and an associated increased efficacy of spontaneous and miniature inhibitory postsynaptic currents in pyramidal neurons. Furthermore, we demonstrate that enhancing phasic GABA signalling using zolpidem, a Food and Drug Administration (FDA)-approved GABA-positive allosteric modulator, during the repair phase improved behavioural recovery. These data identify potentiation of phasic GABA signalling as a novel therapeutic strategy, indicate zolpidem’s potential to improve recovery, and underscore the necessity to distinguish the role of tonic and phasic GABA signalling in stroke recovery. PMID:26685158

  18. Phasic temperature change patterns affect growth and tuberization in potatoes

    SciTech Connect

    Cao, W.; Tibbitts, T.W. . Dept. of Horticulture)

    1994-07-01

    This study determined the response of potato (Solanum tuberosum L., cv. Norland) plants to various patterns of air temperature changes over different growth periods. In each of two experiments under controlled environments, eight treatments of temperature changes were carried out in two growth rooms maintained at 17 and 22 C and a constant vapor pressure deficit of 0.60 kPa and 14-hour photoperiod. Plants were grown for 63 days after transplanting of tissue culture plantlets in 20-liter pots containing peat-vermiculite mix. Temperature changes were imposed on days 21 and 42, which were essentially at the beginning of tuber initiation and tuber enlargement, respectively, for this cultivar. Plants were moved between two temperature rooms to obtain eight temperature change patterns: 17-17-17, 17-17-22, 17-22-17, 22-17-17, 17-22-22, 22-17-22, 22-22-17, and 22-22-22C over three 21-day growth periods. At harvest on day 63, total plant dry weight was higher for the treatments beginning with 22 C than for those beginning with 17C, with highest biomass obtained at 22-22-17 and 22-17-17C. Shoot dry weight increased with temperature increased from 17-17-17 to 22-22-22C during the three growth periods. Tuber dry weight was highest with 22-17-17C, and lowest with 17-17-22 and 17-22-22C. With 22-17-17C, both dry weights of stolons and roots were lowest. Total tuber number and number of small tubers were highest with 17-17-17 and 17-17-22C, and lowest with 17-22-22 and 22-22-22C, whereas number of medium tubers was highest with 22-17-22C, and number of large tubers was highest with 22-17-17C. This study indicates that tuber development of potatoes is optimized with a phasic pattern of high temperature during early growth and low temperature during later growth.

  19. Tonic and phasic co-variation of peripheral arousal indices in infants

    PubMed Central

    Wass, S.V.; de Barbaro, K.; Clackson, K.

    2015-01-01

    Tonic and phasic differences in peripheral autonomic nervous system (ANS) indicators strongly predict differences in attention and emotion regulation in developmental populations. However, virtually all previous research has been based on individual ANS measures, which poses a variety of conceptual and methodlogical challenges to comparing results across studies. Here we recorded heart rate, electrodermal activity (EDA), pupil size, head movement velocity and peripheral accelerometry concurrently while a cohort of 37 typical 12-month-old infants completed a mixed assessment battery lasting approximately 20 min per participant. We analysed covariation of these autonomic indices in three ways: first, tonic (baseline) arousal; second, co-variation in spontaneous (phasic) changes during testing; third, phasic co-variation relative to an external stimulus event. We found that heart rate, head velocity and peripheral accelerometry showed strong positive co-variation across all three analyses. EDA showed no co-variation in tonic activity levels but did show phasic positive co-variation with other measures, that appeared limited to sections of high but not low general arousal. Tonic pupil size showed significant positive covariation, but phasic pupil changes were inconsistent. We conclude that: (i) there is high covariation between autonomic indices in infants, but that EDA may only be sensitive at extreme arousal levels, (ii) that tonic pupil size covaries with other indices, but does not show predicted patterns of phasic change and (iii) that motor activity appears to be a good proxy measure of ANS activity. The strongest patterns of covariation were observed using epoch durations of 40 s per epoch, although significant covariation between indices was also observed using shorter epochs (1 and 5 s). PMID:26316360

  20. Sampling phasic dopamine signaling with fast-scan cyclic voltammetry in awake behaving rats

    PubMed Central

    Fortin, SM; Cone, JJ; Ng-Evans, S; McCutcheon, JE; Roitman, MF

    2015-01-01

    Fast-scan cyclic voltammetry (FSCV) is an electrochemical technique which permits the in vivo measurement of extracellular fluctuations in multiple chemical species. The technique is frequently utilized to sample sub-second (phasic) concentration changes of the neurotransmitter dopamine in awake and behaving rats. Phasic dopamine signaling is implicated in reinforcement, goal-directed behavior, and locomotion and FSCV has been used to investigate how rapid changes in striatal dopamine concentration contribute to these and other behaviors. This unit describes the instrumentation and construction, implantation, and use of necessary components required to sample and analyze dopamine concentration changes in awake rats with FSCV. PMID:25559005

  1. Involvement of 5-hydroxytryptamine7 receptors in inhibition of porcine myometrial contractility by 5-hydroxytryptamine

    PubMed Central

    Kitazawa, Takio; Kubo, Osamu; Satoh, Masami; Taneike, Tetsuro

    1998-01-01

    5-Hydroxytryptamine (5-HT; 1 nM–100 μM) concentration-dependently inhibited the amplitude and frequency of spontaneous contractions in longitudinal and circular muscles of the porcine myometrium. The circular muscle (EC50; 68–84 nM) was more sensitive than the longitudinal muscle (EC50; 1.3–1.44 μM) to 5-HT. To characterize the 5-HT receptor subtype responsible for inhibition of myometrial contractility, the effects of 5-HT receptor agonists on spontaneous contractions and of 5-HT receptor antagonists on inhibition by 5-HT were examined in circular muscle preparations.Pretreatment with tetrodotoxin (1 μM), propranolol (1 μM), atropine (1 μM), guanethidine (10 μM) or L-NAME (100 μM) failed to change the inhibition by 5-HT, indicating that the inhibition was due to a direct action of 5-HT on the smooth muscle cells.5-CT, 5-MeOT and 8-OH-DPAT mimicked the inhibitory response of 5-HT, and the rank order of the potency was 5-CT>5-HT>5-MeOT>8-OH-DPAT. On the other hand, oxymethazoline, α-methyl-5-HT, 2-methyl-5-HT, cisapride, BIMU-1, BIMU-8, ergotamine and dihydroergotamine had almost no effect on spontaneous contractions, even at 10–100 μM.Inhibition by 5-HT was not decreased by either pindolol (1 μM), ketanserin (1 μM), tropisetron (10 μM), MDL72222 (1 μM) or GR113808 (10 μM), but was antagonized by the following compounds in a competitive manner (with pA2 values in parentheses): methiothepin (8.05), methysergide (7.92), metergoline (7.4), mianserin (7.08), clozapine (7.06) and spiperone (6.86).Ro 20-1724 (20 μM) and rolipram (10 μM) significantly enhanced the inhibitory response of 5-HT, but neither zaprinast (10 μM) nor dipyridamole (10 μM) altered the response of 5-HT.5-HT (1 nM–1 μM) caused a concentration-dependent accumulation of intracellular cyclic AMP in the circular muscle.From the present results, the 5-HT receptor, which is functionally correlated with the 5-HT7 receptor, mediates the

  2. BKCa channel regulates calcium oscillations induced by alpha-2-macroglobulin in human myometrial smooth muscle cells.

    PubMed

    Wakle-Prabagaran, Monali; Lorca, Ramón A; Ma, Xiaofeng; Stamnes, Susan J; Amazu, Chinwendu; Hsiao, Jordy J; Karch, Celeste M; Hyrc, Krzysztof L; Wright, Michael E; England, Sarah K

    2016-04-19

    The large-conductance, voltage-gated, calcium (Ca(2+))-activated potassium channel (BKCa) plays an important role in regulating Ca(2+)signaling and is implicated in the maintenance of uterine quiescence during pregnancy. We used immunopurification and mass spectrometry to identify proteins that interact with BKCain myometrium samples from term pregnant (≥37 wk gestation) women. From this screen, we identified alpha-2-macroglobulin (α2M). We then used immunoprecipitation followed by immunoblot and the proximity ligation assay to confirm the interaction between BKCaand both α2M and its receptor, low-density lipoprotein receptor-related protein 1 (LRP1), in cultured primary human myometrial smooth muscle cells (hMSMCs). Single-channel electrophysiological recordings in the cell-attached configuration demonstrated that activated α2M (α2M*) increased the open probability of BKCain an oscillatory pattern in hMSMCs. Furthermore, α2M* caused intracellular levels of Ca(2+)to oscillate in oxytocin-primed hMSMCs. The initiation of oscillations required an interaction between α2M* and LRP1. By using Ca(2+)-free medium and inhibitors of various Ca(2+)signaling pathways, we demonstrated that the oscillations required entry of extracellular Ca(2+)through store-operated Ca(2+)channels. Finally, we found that the specific BKCablocker paxilline inhibited the oscillations, whereas the channel opener NS11021 increased the rate of these oscillations. These data demonstrate that α2M* and LRP1 modulate the BKCachannel in human myometrium and that BKCaand its immunomodulatory interacting partners regulate Ca(2+)dynamics in hMSMCs during pregnancy. PMID:27044074

  3. Linking Myometrial Physiology to Intrauterine Pressure; How Tissue-Level Contractions Create Uterine Contractions of Labor

    PubMed Central

    Young, Roger C.; Barendse, Peter

    2014-01-01

    The mechanisms used to coordinate uterine contractions are not known. We develop a new model based on the proposal that there is a maximum distance to which action potentials can propagate in the uterine wall. This establishes “regions”, where one action potential burst can rapidly recruit all the tissue. Regions are recruited into an organ-level contraction via a stretch-initiated contraction mechanism (myometrial myogenic response). Each uterine contraction begins with a regional contraction, which slightly increases intrauterine pressure. Higher pressure raises tension throughout the uterine wall, which initiates contractions of more regions and further increases pressure. The positive feedback synchronizes regional contractions into an organ-level contraction. Cellular automaton (CA) simulations are performed with Mathematica. Each “cell” is a region that is assigned an action potential threshold. An anatomy sensitivity factor converts intrauterine pressure to regional tension through the Law of Laplace. A regional contraction occurs when regional tension exceeds regional threshold. Other input variables are: starting and minimum pressure, burst and refractory period durations, enhanced contractile activity during an electrical burst, and reduced activity during the refractory period. Complex patterns of pressure development are seen that mimic the contraction patterns observed in laboring women. Emergent behavior is observed, including global synchronization, multiple pace making regions, and system memory of prior conditions. The complex effects of nifedipine and oxytocin exposure are simulated. The force produced can vary as a nonlinear function of the number of regions. The simulation directly links tissue-level physiology to human labor. The concept of a uterine pacemaker is re-evaluated because pace making activity may occur well before expression of a contraction. We propose a new classification system for biological CAs that parallels the 4

  4. Alterations in ovine myometrial beta-adrenergic cascade do not mediate tachyphylaxis to ritodrine.

    PubMed

    Daftary, A; Chiao, J P; Caritis, S N

    1996-01-01

    The purpose of this study was to determine in vivo the dose response relationship between beta-adrenergic receptor (BAR) agonist concentration and various elements of the BAR cascade: receptor density, hormone-stimulable adenylyl cyclase activity, and contraction inhibition. A previously described, chronically-catheterized ovine model was used. Ritodrine was infused continuously over 24 h in 22 mixed-breed sheep. Each animal received a single, constant infusion rate. Myometrial biopsies were obtained before and after the drug infusions. BAR density was determined using tritiated dihydroalprenolol. Adenylyl cyclase activity was determined using the Gilman competitive protein-binding assay. Intermittent oxytocin boluses were given into the maternal aorta and contractile response was determined. Infusion rates of 0.06-4.0 micrograms/kg/min yielded steady-state ritodrine serum concentrations of 5-168 ng/ml. No significant correlation was found between the ritodrine concentration and the magnitude of decrease in BAR density. Significant correlations existed, however, between the ritodrine concentration and both the magnitude of decrease in adenylyl cyclase activity and the loss of contraction inhibition. There was no correlation noted between the BAR cascade alterations and the loss of contraction inhibition. Despite significant reductions in receptor density (down regulation) and dose-related reductions in hormone-stimulable adenylyl cyclase activity (uncoupling), ritodrine at low concentrations was still able to inhibit oxytocin-induced contractions, i.e., tachyphylaxis did not occur. Tachyphylaxis appeared to correlate only with the serum ritodrine concentration. Hence, alterations in the BAR cascade do not necessarily equate with a loss of end-organ response (tachyphylaxis). Previous concepts based on in vitro studies about the interaction of the BAR agonist with its receptor, the subsequent generation of intracellular messengers, and the resultant end

  5. [The mechanism of beta-receptor desensitization in human myometrial culture cell].

    PubMed

    Okamura, Y; Oku, M; Fujii, E; Otsuki, T; Adachi, S; Morimoto, K

    1995-01-01

    Beta-adrenoceptor desensitization is considered to be primarily due to phosphorylation of receptors by protein kinase A (PKA) and beta-adrenaline receptor kinase (beta-ARK) and sequestration of receptors themselves. But in the human uterine muscle, the desensitization mechanism has been evaluated only as a phenomenon, and there are few studies on its mechanism. We evaluated cAMP production by beta-agonist and changes in the number of beta-receptors in cultured human myometrial cells. Uterine muscle cell were obtained from patients with benign disease before menopause and cultured. 1) At the confluent stage, dl-Isoproterenol Hydrochloride (ISP) was added under various conditions, and the intracellular cAMP concentration was determined by EIA. 2) After the addition of ISP (10(-6) M), plates were incubated at 37 degrees C, and beta-AR on the cell membrane surface (S beta-AR) and total beta-AR (T beta-AR) was measured in a binding assay with 125I-pindolol. The production of cAMP dose-dependently increased 30 minutes after the addition of ISP at 10(-6) M or higher, but rapidly decreased thereafter. T beta-AR was similar in the cells treated with ISP (10(-6) M) and the untreated cells. On the other hand, S beta-AR decreased by about 50% in the ISP treated cells. These result suggest the desensitization of beta-AR in human uterine muscle, and the involvement of the sequestration mechanism as its cause.

  6. Regional Variation in Phasic Dopamine Release during Alcohol and Sucrose Self-Administration in Rats

    PubMed Central

    2015-01-01

    While dopamine input to the dorsal striatum is well-known to be critical for action selection, including alcohol-motivated behaviors, it is unknown whether changes in phasic dopamine accompany these behaviors. Long-term alcohol abuse is believed to promote alterations in the neurocircuitry of reward learning in both ventral and dorsal striatum, potentially through increasing dopamine release. Using fast-scan cyclic voltammetry, we measured phasic dopamine release in the dorsal and ventral striatum during alcoholic and nonalcoholic reward-seeking behavior and reward-related cues in rats trained on a variable-interval schedule of reinforcement. We observed robust phasic dopamine release in the dorsolateral striatum after reinforced lever presses and inconsistent dopamine release in the dorsomedial striatum. Contrary to our expectations, alcohol did not enhance dopamine release in rats drinking alcoholic rewards. Cue-induced dopamine release was also observed in the nucleus accumbens core of rats drinking the reward solutions. These data demonstrate that alcoholic and nonalcoholic reward self-administration on a variable-interval schedule of reinforcement in rats is accompanied by phasic dopamine release time-locked to reinforcement in the dorsolateral striatum and the nucleus accumbens, but not the dorsomedial striatum. PMID:25493956

  7. Excitation of phasically firing hypothalamic supraoptic neurones by carotid occlusion in rats.

    PubMed Central

    Dreifuss, J J; Harris, M C; Tribollet, E

    1976-01-01

    1. The activity of supraoptic neurones has been recorded extracellularly during bilateral occlusion of the common carotid arteries in anaesthetized rats. 2. Experiments in lactating rats showed that occlusion liberated sufficient amounts of neurohypophysial hormones to cause a rise in intramammary pressure 15-25 s after the onset of occlusion. 3. Ninety-one percent of the phasic neurones (defined as those showing bursts of activity alternating with periods of silence) were activated by carotid occlusion less than 10 s after the onset of occlusion. Most randomly firing neurones were inhibited or were unaffected. 4. The activation of phasic neurones is unlikely to be just a nonspecific effect, because in the same animals, phasic neurones were excited whilst random neurones were not. 5. Moreover, in phasic neurones, statistical analysis shows (a) that the intervals during which an occlusion was performed were significantly shorter than the intervals between spontaneously occurring bursts, and (b) that this activation was followed by a period of reduced firing probability. 6. The results are discussed with reference to the correlation of supraoptic neuronal activity with hormone release. The possibility is considered of relating the tendency of some supraoptic neurones to fire in bursts with the secretion of vasopressin. PMID:950597

  8. The adverse effects of aldrin and dieldrin on both myometrial contractions and the secretory functions of bovine ovaries and uterus in vitro

    SciTech Connect

    Wrobel, Michał H. Grzeszczyk, Marlena; Mlynarczuk, Jaroslaw; Kotwica, Jan

    2015-05-15

    Aldrin and dieldrin are chloroorganic insecticides which are recognised as endocrine disruptors. The aim of the study was to investigate their effect on the secretory functions of the uterus and ovary and on myometrial contractions. Myometrial strips and uterine and ovarian cells from nonpregnant cows were incubated with the xenobiotics (0.1, 1 or 10 ng/ml) for 24 or 72 h. Next, their effect on viability of myometrial, endometrial, granulosa and luteal cells, myometrial strip contractions, the synthesis and secretion of prostaglandins (PGs: PGF2α and PGE2) from uterine cells, the secretion of oestradiol (E2), testosterone (T) and oxytocin (OT) from granulosa cells and the secretion of progesterone (P4) and OT from luteal cells were determined. Neither of the xenobiotics (10 ng/ml) affected (P > 0.05) the viability of the ovarian and uterine cells, while both (0.1–10 ng/ml) decreased (P < 0.05) the basal and OT-stimulated myometrial contractions. In spite of these effects, neither of the insecticides affected (P > 0.05) the synthesis and the secretion of PGs from the myometrial cells. Although they also did not impair the secretion of the PGs from the endometrial cells, they abolished (P < 0.05) the stimulatory effect of OT (P < 0.05) on the secretion of the PGs and stimulated (P < 0.05) the secretion of OT from the granulosa and luteal cells. Moreover, aldrin and dieldrin stimulated secretion of E2 and T from the granulosa cells, while only dieldrin increased (P < 0.05) the secretion of P4 from luteal cells. The data show that aldrin and dieldrin stimulated the secretory function of the cultured granulosa and luteal cells and inhibited the myometrial contractions of cows in vitro, which may affect on natural parturition. - Highlights: • Aldrin and dieldrin inhibited bovine myometrial contractions. • The studied xenobiotics stimulated steroids and oxytocin secretion from ovaries. • Prostaglandins are not involved in adverse effect of the xenobiotics on

  9. Effects of experimental cardiac volume loading on left atrial phasic function in healthy dogs.

    PubMed

    Osuga, Tatsuyuki; Nakamura, Kensuke; Morita, Tomoya; Nisa, Khoirun; Yokoyama, Nozomu; Sasaki, Noboru; Morishita, Keitaro; Ohta, Hiroshi; Takiguchi, Mitsuyoshi

    2016-09-01

    OBJECTIVE To elucidate the relationship between acute volume overload and left atrial phasic function in healthy dogs. ANIMALS 6 healthy Beagles. PROCEDURES Dogs were anesthetized. A Swan-Ganz catheter was placed to measure mean pulmonary capillary wedge pressure (PCWP). Cardiac preload was increased by IV infusion with lactated Ringer solution at 150 mL/kg/h for 90 minutes. Transthoracic echocardiography was performed before (baseline) and at 15, 30, 45, 60, 75, and 90 minutes after volume loading began. At each echocardiographic assessment point, apical 4-chamber images were recorded and analyzed to derive time-left atrial area curves. Left atrial total (for reservoir function), passive (for conduit function), and active (for booster-pump function) fractional area changes were calculated from the curves. RESULTS Volume overload resulted in a significant increase from baseline in PCWP from 15 to 90 minutes after volume loading began. All fractional area changes at 15 to 90 minutes were significantly increased from baseline. In multiple regression analysis, quadratic regression models were better fitted to the relationships between PCWP and each of the total and active fractional area changes than were linear regression models. A linear regression model was better fitted to the relationship between PCWP and passive fractional area change. CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that left atrial phasic function assessed on the basis of left atrial phasic areas was enhanced during experimental cardiac volume loading in healthy dogs. The effect of volume load should be considered when evaluating left atrial phasic function by indices derived from left atrial phasic sizes. PMID:27580106

  10. Ghrelin regulates phasic dopamine and nucleus accumbens signaling evoked by food-predictive stimuli

    PubMed Central

    Cone, Jackson J.; Roitman, Jamie D.; Roitman, Mitchell F.

    2015-01-01

    Environmental stimuli that signal food availability hold powerful sway over motivated behavior and promote feeding, in part, by activating the mesolimbic system. These food-predictive cues evoke brief (phasic) changes in nucleus accumbens (NAc) dopamine concentration and in the activity of individual NAc neurons. Phasic fluctuations in mesolimbic signaling have been directly linked to goal-directed behaviors, including behaviors elicited by food-predictive cues. Food-seeking behavior is also strongly influenced by physiological state (i.e. hunger vs. satiety). Ghrelin, a stomach hormone that crosses the blood-brain barrier, is linked to the perception of hunger and drives food intake, including intake potentiated by environmental cues. Notwithstanding, whether ghrelin regulates phasic mesolimbic signaling evoked by food-predictive stimuli is unknown. Here, rats underwent Pavlovian conditioning in which one cue predicted the delivery of rewarding food (CS+) and a second cue predicted nothing (CS−). After training, we measured the effect of ghrelin infused into the lateral ventricle (LV) on sub-second fluctuations in NAc dopamine using fast-scan cyclic voltammetry and individual NAc neuron activity using in vivo electrophysiology in separate groups of rats. LV ghrelin augmented both phasic dopamine and phasic increases in the activity of NAc neurons evoked by the CS+. Importantly, ghrelin did not affect the dopamine nor NAc neuron response to the CS−, suggesting that ghrelin selectively modulated mesolimbic signaling evoked by motivationally significant stimuli. These data demonstrate that ghrelin, a hunger signal linked to physiological state, can regulate cue-evoked mesolimbic signals that underlie food-directed behaviors. PMID:25708523

  11. Myometrial oxytocin receptor mRNA concentrations at preterm and term delivery - the influence of external oxytocin.

    PubMed

    Liedman, Ragner; Hansson, Stefan Rocco; Igidbashian, Sarah; Akerlund, Mats

    2009-03-01

    The hormonal system for induction of term and preterm labour is not fully understood. Therefore, we investigated myometrial gene expressions for neurohypophyseal hormones and their receptors, prostaglandin F(2alpha) and ovarian steroid receptors in women delivered by Caesarean section. Myometrial tissue for real time PCR was collected from 39 women delivered at term before and after the onset of labour and preterm. Women delivered electively at term had significantly higher oxytocin receptor mRNA expressions (2.52 +/- 0.37 oxytocin receptor/actin; median +/- SEM) than those delivered with ongoing labour at term (1.01 +/- 0.34; p = 0.015) and those at preterm (1.08 +/- 0.25; p = 0.004). Sub-analyses revealed that the difference at term pregnancies solely was related to patients receiving oxytocin during labour (p = 0.007). These patients had higher oxytocin peptide mRNA levels than those without labour at term (p = 0.009). PGF(2alpha) receptor mRNA concentrations were 27.80 +/- 3.55, 11.46 +/- 2.87 and 19.54 +/- 5.52 PGF receptor/actin, respectively, for the groups. Women without labour at term had higher concentration than those with labour (p = 0.005). Our results suggest that oxytocin, its receptor and the PGF(2alpha) receptor are involved in the regulation of labour through a paracrine mechanism.

  12. Role of PKC and RhoA/ROCK pathways in the spontaneous phasic activity in the rectal smooth muscle.

    PubMed

    Singh, Jagmohan; Rattan, Satish

    2013-04-15

    The role of PKC and RhoA/ROCK pathways in the phasic activities in the rectal smooth muscles (RSM) in the basal state is not known. We examined this issue by determining the effects of PKC inhibitors (calphostin C and Gö-6850) and a ROCK inhibitor (Y-27632) on the slow-rate (~3/min) and fast-rate (~25/min) phasic activities. We also examined the corresponding signal transduction cascades and the PKC and ROCK enzymatic activities in the RSM in the basal state. PKC inhibition with calphostin C and Gö-6850 (10(-5) M) caused a significant decrease (~25%) in slow-rate (but not fast-rate) phasic activity (monitored by frequency and amplitude of contractions) of the RSM. Conversely, ROCK inhibition with Y-27632 (10(-5) M) caused a significant decrease not only in slow-rate, but also fast-rate, phasic activity caused by ROCK inhibition in the RSM. Western blot analysis revealed that the PKC inhibition-induced decrease in RSM phasic activity was associated with decreases in PKCα translocation, phosphorylated (Thr(38)) PKC-potentiated inhibitor (CPI-17), and phosphorylated (Thr(18)/Ser(19)) 20-kDa myosin regulatory light chain. Conversely, decreases in the phasic activity in the RSM by ROCK inhibition were accompanied by the additional decrease in phosphorylated (Thr(696)) myosin phosphatase target subunit 1. Data show that while PKC and RhoA/ROCK pathways play a significant role in slow-rate high-amplitude spontaneous phasic activity, only the RhoA/ROCK pathway primarily mediates fast-rate low-amplitude phasic activity, in the RSM. Such knowledge is important in the understanding of the pathophysiology of large intestinal motility disorders. Relative contributions of the PKC vs. the RhoA/ROCK pathway in the phasic activity remain to be determined.

  13. Bi-phasic titanium dioxide nanoparticles doped with nitrogen and neodymium for enhanced photocatalysis

    NASA Astrophysics Data System (ADS)

    Gomez, Virginia; Bear, Joseph C.; McNaughter, Paul D.; McGettrick, James D.; Watson, Trystan; Charbonneau, Cecile; O'Brien, Paul; Barron, Andrew R.; Dunnill, Charles W.

    2015-10-01

    Bi-phasic or multi-phasic composite nanoparticles for use in photocatalysis have been produced by a new synthetic approach. Sol-gel methods are used to deposit multiple layers of active material onto soluble substrates. In this work, a layer of rutile (TiO2) was deposited onto sodium chloride pellets followed by an annealing step and a layer of anatase. After dissolving the substrate, bi-phasic nanoparticles containing half anatase and half rutile TiO2; with ``Janus-like'' characteristics are obtained. Nitrogen and neodymium doping of the materials were observed to enhance the photocatalytic properties both under UV and white light irradiation. The unique advantage of this synthetic method is the ability to systematically dope separate sides of the nanoparticles. Nitrogen doping was found to be most effective on the anatase side of the nanoparticle while neodymium was found to be most effective on the rutile side. Rhodamine B dye was effectively photodegraded by co-doped particles under white light.Bi-phasic or multi-phasic composite nanoparticles for use in photocatalysis have been produced by a new synthetic approach. Sol-gel methods are used to deposit multiple layers of active material onto soluble substrates. In this work, a layer of rutile (TiO2) was deposited onto sodium chloride pellets followed by an annealing step and a layer of anatase. After dissolving the substrate, bi-phasic nanoparticles containing half anatase and half rutile TiO2; with ``Janus-like'' characteristics are obtained. Nitrogen and neodymium doping of the materials were observed to enhance the photocatalytic properties both under UV and white light irradiation. The unique advantage of this synthetic method is the ability to systematically dope separate sides of the nanoparticles. Nitrogen doping was found to be most effective on the anatase side of the nanoparticle while neodymium was found to be most effective on the rutile side. Rhodamine B dye was effectively photodegraded by co

  14. Treatment of oophorectomized guinea pigs with intrauterine 17 beta-estradiol pellets may modulate myometrial beta-adrenergic receptor binding properties.

    PubMed

    Hatjis, C G; Grogan, D M; Koritnik, D R

    1989-12-01

    Intrauterine 17 beta-estradiol pellets can induce an up-regulation of guinea pig myometrial beta-adrenergic receptor density and l-isoproterenol-dependent adenylate cyclase activity. Does 17 beta-estradiol influence the ability of beta-adrenergic receptors to form a "high affinity" state with l-isoproterenol, which is a necessary step for adenylate cyclase activation? Nonpregnant, oophorectomized guinea pigs received intrauterine pellets of either placebo, 17 beta-estradiol, progesterone, or 17 beta-estradiol plus progesterone for 1 week. 17 beta-Estradiol resulted in pharmacologic, whereas progesterone resulted in physiologic plasma 17 beta-estradiol and progesterone concentrations, respectively. The affinity of myometrial beta-adrenergic receptors for l-isoproterenol was measured by percentage of inhibition of -[125I]cyanopindolol binding. In all groups, the competition curves in the presence of magnesium chloride could be resolved into two affinity states of the beta-adrenergic receptor, "high" and "low," respectively. The ratio of their dissociation constants was not influenced by hormonal treatment. However, the relative concentration of beta-adrenergic receptors in the high affinity state was significantly higher in the 17 beta-estradiol-treated group than that in the control group. This correlates with the up-regulation in myometrial adenylate cyclase activity and suggests that myometrial beta-adrenergic receptor-adenylate cyclase function may be modulated by 17 beta-estradiol.

  15. Progesterone Receptor-A and -B Have Opposite Effects on Proinflammatory Gene Expression in Human Myometrial Cells: Implications for Progesterone Actions in Human Pregnancy and Parturition

    PubMed Central

    Tan, Huiqing; Yi, Lijuan; Rote, Neal S.; Hurd, William W.

    2012-01-01

    Context: Progesterone promotes uterine relaxation during pregnancy and its withdrawal induces labor. Progesterone withdrawal in human parturition is mediated in part by changes in the relative levels of the nuclear progesterone receptor isoforms, PR-A and PR-B, in myometrial cells. Parturition also involves myometrial inflammation; however, the functional link between nuclear PR-mediated progesterone actions and inflammation in human myometrial cells is unclear. Objective: Our objective was to determine how PR-A and PR-B regulate progesterone action in human myometrial cells and specifically the expression of genes encoding contraction-associated proteins and proinflammatory mediators. Design: Effects of PR-A and PR-B on the capacity for progesterone to modulate gene expression was determined using an immortalized human myometrial cell line stably transfected with inducible PR-A and PR-B expression transgenes and conditioned to express various PR-A and PR-B levels. Gene expression was assessed by genome wide transcriptome analysis, quantitative RT-PCR and immunoblotting. Results: PR-A and PR-B were each transcriptionally active in response to progesterone and affected the expression of distinct gene cohorts. The capacity for progesterone to affect gene expression was dependent on the PR-A to PR-B ratio. This was especially apparent for the expression of proinflammatory genes. Progesterone decreased proinflammatory gene expression when the PR-A to PR-B ratio favored PR-B and increased proinflammatory gene expression when the ratio favored PR-A. Progesterone via PR-B increased expression of inhibitor-κBα, a repressor of the nuclear factor-κB transcription factor, and inhibited basal and lipopolysaccharide-induced proinflammatory gene expression. Both of those PR-B-mediated effects were inhibited by PR-A. Conclusions: Our data suggest that during most of human pregnancy, when myometrial cells are PR-B dominant, progesterone promotes myometrial quiescence through PR

  16. Dose-dependent biphasic leptin-induced proliferation is caused by non-specific IL-6/NF-κB pathway activation in human myometrial cells

    PubMed Central

    Barrichon, Marina; Hadi, Tarik; Wendremaire, Maeva; Ptasinski, Clémentine; Seigneuric, Renaud; Marcion, Guillaume; Delignette, Marc; Marchet, Jacques; Dumas, Monique; Sagot, Paul; Bardou, Marc; Garrido, Carmen; Lirussi, Frédéric

    2015-01-01

    Background and Purpose Leptin, an adipokine synthesized by the placenta during pregnancy, has been proposed for the management of preterm labour (PTL), as it is able to prevent in vitro uterine contractility and remodelling associated with labour onset. Another common feature of labour onset is the phenotypic switch of myometrial smooth muscle cells from a proliferative to a hypertrophic state. As proliferative effects have been demonstrated for leptin in other tissues, we aimed to investigate its ability to induce myometrial proliferation and thus to maintain uterine quiescence. Experimental Approach We stimulated human primary myometrial smooth muscle cells with leptin in the presence or absence of receptor antagonists or signalling pathway inhibitors. Key Results Leptin induced myometrial cell proliferation in a biphasic manner. At 6.25 ng·mL−1, leptin-induced proliferation was mediated by the leptin receptor and required the early activation of ERK1/2. At a concentration above 25 ng·mL−1, leptin induced direct non-specific stimulation of the IL-6 receptor, leading to NF-κB activation, and exerted anti-proliferative effects. However, at 50 ng·mL−1, leptin re-induces proliferation via IL-6 receptor stimulation that requires STAT3 and delayed ERK1/2 activation. Conclusions and Implications These data bring new insights into leptin signalling-induced myometrial proliferation and its interrelationship with the IL-6/IL-6 receptor axis. In the light of our previous work, the present study emphasizes the potential value of leptin in the pharmacological management of PTL and it also strengthens the hypothesis that leptin might be a contributory factor in the parturition-related disorders observed in obese women. PMID:25653112

  17. Influences of NREM sleep on the activity of tonic vs. inspiratory phasic muscles in normal men.

    PubMed

    Tangel, D J; Mezzanotte, W S; Sandberg, E J; White, D P

    1992-09-01

    Studies of sleep influences on human pharyngeal and other respiratory muscles suggest that the activity of these muscles may be affected by non-rapid-eye-movement (NREM) sleep in a nonuniform manner. This variable sleep response may relate to the pattern of activation of the muscle (inspiratory phasic vs. tonic) and peripheral events occurring in the airway. Furthermore, the ability of these muscles to respond to respiratory stimuli during NREM sleep may also differ. To systematically investigate the effect of NREM sleep on respiratory muscle activity, we studied two tonic muscles [tensor palatini (TP), masseter (M)] and two inspiratory phasic ones [genioglossus (GG), diaphragm (D)], also measuring the response of these muscles to inspiratory resistive loading (12 cmH2O.l-1.s) during wakefulness and NREM sleep. Seven normal male subjects were studied on a single night with intramuscular electrodes placed in the TP and GG and surface electrodes placed over the D and M. Sleep stage, inspiratory airflow, and moving time average electromyograph (EMG) of the above four muscles were continuously recorded. The EMG of both tonic muscles fell significantly (P less than 0.05) during NREM sleep [TP awake, 4.3 +/- 0.05 (SE) arbitrary units, stage 2, 1.1 +/- 0.2; stage 3/4, 1.0 +/- 0.2. Masseter awake, 4.8 +/- 0.6; stage 2, 3.3 +/- 0.5; stage 3/4, 3.1 +/- 0.5]. On the other hand, the peak phasic EMG of both inspiratory phasic muscles (GG and D) was well maintained.(ABSTRACT TRUNCATED AT 250 WORDS)

  18. Two-way ANOVA for scalar trajectories, with experimental evidence of non-phasic interactions.

    PubMed

    Pataky, Todd C; Vanrenterghem, Jos; Robinson, Mark A

    2015-01-01

    Kinematic and force trajectories are often normalized in time, with mean and variance summary statistic trajectories reported. It has been shown elsewhere, for simple one-factor experiments, that statistical testing can be conducted directly on those summary statistic trajectories using Random Field Theory (RFT). This technical note describes how RFT extends to two-factor designs, and how bizarre "non-phasic interactions" can occur in multi-factor experiments. We reanalyzed a public dataset detailing stance phase knee flexion during walking in (a) patellofemoral pain vs. controls, and (b) females vs. males using both a full model (with interaction effect) and a main-effects-only model. In both models the main effect of PAIN failed to reach significance at α=0.05. The main effect of GENDER reached significance over 5-40% stance (p=0.0005), but only for the full model. The interaction effect (in the full model) reached significance over 0-15% of stance (p=0.030), and resulted from greater flexion in females but decreased flexion in males in PFP vs. controls. Thus there was a non-phasic interaction in which a non-significant interaction (over 20-40% stance) suppressed the main effect of GENDER. Similarly, if we had only analyzed 20-40% stance, we would have committed Type II error by failing to reject the null PAIN-GENDER interaction hypothesis. The possible presence of non-phasic interactions implies that trajectory analyses must be conducted at the whole-trajectory level, because a failure to do so will generally miss non-phasic interactions if present.

  19. Interactions between phasic alerting and consciousness in the fronto-striatal network.

    PubMed

    Chica, Ana B; Bayle, Dimitri J; Botta, Fabiano; Bartolomeo, Paolo; Paz-Alonso, Pedro M

    2016-01-01

    Only a small fraction of all the information reaching our senses can be the object of conscious report or voluntary action. Although some models propose that different attentional states (top-down amplification and vigilance) are necessary for conscious perception, few studies have explored how the brain activations associated with different attentional systems (such as top-down orienting and phasic alerting) lead to conscious perception of subsequent visual stimulation. The aim of the present study was to investigate the neural mechanisms associated with endogenous spatial attention and phasic alertness, and their interaction with the conscious perception of near-threshold stimuli. The only region demonstrating a neural interaction between endogenous attention and conscious perception was the thalamus, while a larger network of cortical and subcortical brain activations, typically associated with phasic alerting, was highly correlated with participants' conscious reports. Activation of the anterior cingulate cortex, supplementary motor area, frontal eye fields, thalamus, and caudate nucleus was related to perceptual consciousness. These data suggest that not all attentional systems are equally effective in enhancing conscious perception, highlighting the importance of thalamo-cortical circuits on the interactions between alerting and consciousness. PMID:27555378

  20. The accessory stimulus effect is mediated by phasic arousal: A pupillometry study.

    PubMed

    Tona, Klodiana-Daphne; Murphy, Peter R; Brown, Stephen B R E; Nieuwenhuis, Sander

    2016-07-01

    People usually respond faster to a visual stimulus when it is immediately preceded by a task-irrelevant, auditory accessory stimulus (AS). This AS effect occurs even in choice reaction time tasks, despite the fact that the AS carries no information about the correct response. Researchers often assume that the AS effect is mediated by a phasic arousal burst evoked by the AS, but direct evidence for that assumption is lacking. We conducted a pupillometry study to directly test the phasic arousal hypothesis. Participants carried out a demanding choice reaction time task with accessory stimuli occurring on 25% of the trials. Pupil diameter, a common index of arousal, was measured throughout the task. Standard analyses of task performance and pupil diameter showed that participants exhibited the typical AS effect, and that accessory stimuli evoked a reliable early pupil dilation on top of the more protracted dilation associated with the imperative stimulus. Moreover, regression analyses at the single-trial level showed that variation in reaction times on AS trials was selectively associated with pupil dilation during the early time window within which the AS had an effect, such that particularly large AS-evoked dilations were associated with especially fast responses. These results provide the first evidence that the AS effect is mediated by AS-evoked phasic arousal.

  1. Bi-phasic titanium dioxide nanoparticles doped with nitrogen and neodymium for enhanced photocatalysis.

    PubMed

    Gomez, Virginia; Bear, Joseph C; McNaughter, Paul D; McGettrick, James D; Watson, Trystan; Charbonneau, Cecile; O'Brien, Paul; Barron, Andrew R; Dunnill, Charles W

    2015-11-14

    Bi-phasic or multi-phasic composite nanoparticles for use in photocatalysis have been produced by a new synthetic approach. Sol-gel methods are used to deposit multiple layers of active material onto soluble substrates. In this work, a layer of rutile (TiO2) was deposited onto sodium chloride pellets followed by an annealing step and a layer of anatase. After dissolving the substrate, bi-phasic nanoparticles containing half anatase and half rutile TiO2; with "Janus-like" characteristics are obtained. Nitrogen and neodymium doping of the materials were observed to enhance the photocatalytic properties both under UV and white light irradiation. The unique advantage of this synthetic method is the ability to systematically dope separate sides of the nanoparticles. Nitrogen doping was found to be most effective on the anatase side of the nanoparticle while neodymium was found to be most effective on the rutile side. Rhodamine B dye was effectively photodegraded by co-doped particles under white light.

  2. Sustained N-methyl-D-aspartate receptor hypofunction remodels the dopamine system and impairs phasic signaling

    PubMed Central

    Ferris, Mark J.; Milenkovic, Marija; Liu, Shuai; Mielnik, Catharine A.; Beerepoot, Pieter; John, Carrie E.; España, Rodrigo A.; Sotnikova, Tatyana D.; Gainetdinov, Raul R.; Borgland, Stephanie L.; Jones, Sara R.; Ramsey, Amy J.

    2014-01-01

    Chronic N-methyl-D-aspartate receptor (NMDAR) hypofunction has been proposed as a contributing factor to symptoms of schizophrenia. However, it is unclear how sustained NMDAR hypofunction throughout development affects other neurotransmitter systems that have been implicated in the disease. Dopamine neuron biochemistry and activity were examined to determine whether sustained NMDAR hypofunction causes a state of hyperdopaminergia. We report that a global, genetic reduction in NMDARs led to a remodeling of dopamine neurons, substantially affecting two key regulators of dopamine homeostasis, i.e. tyrosine hydroxylase and the dopamine transporter. In NR1 knockdown mice, dopamine synthesis and release were attenuated, and dopamine clearance was increased. Although these changes would have the effect of reducing dopamine transmission, we demonstrated that a state of hyperdopaminergia existed in these mice because dopamine D2 autoreceptors were desensitized. In support of this conclusion, NR1 knockdown dopamine neurons have higher tonic firing rates. Although the tonic firing rates are higher, phasic signaling is impaired, and dopamine overflow cannot be achieved with exogenous high-frequency stimulation that models phasic firing. Through the examination of several parameters of dopamine neurotransmission, we provide evidence that chronic NMDAR hypofunction leads to a state of elevated synaptic dopamine. Compensatory mechanisms to attenuate hyperdopaminergia also impact the ability to generate dopamine surges through phasic firing. PMID:24754704

  3. Phasic Treatment with Interferon Gamma Stimulates Release of Exosomes that Protect Against Spreading Depression.

    PubMed

    Pusic, Aya D; Kraig, Richard P

    2015-10-01

    The detrimental effects of T-cell-secreted interferon gamma (IFNγ) on oxidative stress (OS) and demyelination in multiple sclerosis (MS) are well recognized. Recently, we demonstrated that IFNγ-mediated damage to myelin also increases susceptibility to spreading depression (SD; the likely basis of migraine with aura). However, before onset of MS, induction of physiological levels of IFNγ, like that produced by environmental enrichment (EE), protects against demyelination and OS. Accordingly, we focused on the potential for physiological levels of IFNγ to protect against SD. EE, which occurs with a moderate and phasic increase in proinflammatory cytokines, reduces migraine frequency. Thus, we applied phasic or pulsed IFNγ to brain slice cultures to emulate EE. This treatment reduced OS, increased myelin basic protein, a marker for myelin, and reduced susceptibility to SD. Building on our research on exosomes in EE-based neuroprotection, we found that IFNγ stimulation of slice cultures induced release of exosomes, likely from the microglia that produce the same protective effects as IFNγ treatment when applied to naive cultures. Finally, nasal administration of IFNγ to rats recapitulated in vitro effects, reducing OS, increasing myelin, and reducing SD. These results support phasic IFNγ signaling as a therapeutic target for prevention of SD and, by extension, migraine.

  4. Interactions between phasic alerting and consciousness in the fronto-striatal network

    PubMed Central

    Chica, Ana B.; Bayle, Dimitri J.; Botta, Fabiano; Bartolomeo, Paolo; Paz-Alonso, Pedro M.

    2016-01-01

    Only a small fraction of all the information reaching our senses can be the object of conscious report or voluntary action. Although some models propose that different attentional states (top-down amplification and vigilance) are necessary for conscious perception, few studies have explored how the brain activations associated with different attentional systems (such as top-down orienting and phasic alerting) lead to conscious perception of subsequent visual stimulation. The aim of the present study was to investigate the neural mechanisms associated with endogenous spatial attention and phasic alertness, and their interaction with the conscious perception of near-threshold stimuli. The only region demonstrating a neural interaction between endogenous attention and conscious perception was the thalamus, while a larger network of cortical and subcortical brain activations, typically associated with phasic alerting, was highly correlated with participants’ conscious reports. Activation of the anterior cingulate cortex, supplementary motor area, frontal eye fields, thalamus, and caudate nucleus was related to perceptual consciousness. These data suggest that not all attentional systems are equally effective in enhancing conscious perception, highlighting the importance of thalamo-cortical circuits on the interactions between alerting and consciousness. PMID:27555378

  5. Phasic, Nonsynaptic GABA-A Receptor-Mediated Inhibition Entrains Thalamocortical Oscillations

    PubMed Central

    Rovó, Zita; Mátyás, Ferenc; Barthó, Péter; Slézia, Andrea; Lecci, Sandro; Pellegrini, Chiara; Astori, Simone; Dávid, Csaba; Hangya, Balázs

    2014-01-01

    GABA-A receptors (GABA-ARs) are typically expressed at synaptic or nonsynaptic sites mediating phasic and tonic inhibition, respectively. These two forms of inhibition conjointly control various network oscillations. To disentangle their roles in thalamocortical rhythms, we focally deleted synaptic, γ2 subunit-containing GABA-ARs in the thalamus using viral intervention in mice. After successful removal of γ2 subunit clusters, spontaneous and evoked GABAergic synaptic currents disappeared in thalamocortical cells when the presynaptic, reticular thalamic (nRT) neurons fired in tonic mode. However, when nRT cells fired in burst mode, slow phasic GABA-AR-mediated events persisted, indicating a dynamic, burst-specific recruitment of nonsynaptic GABA-ARs. In vivo, removal of synaptic GABA-ARs reduced the firing of individual thalamocortical cells but did not abolish slow oscillations or sleep spindles. We conclude that nonsynaptic GABA-ARs are recruited in a phasic manner specifically during burst firing of nRT cells and provide sufficient GABA-AR activation to control major thalamocortical oscillations. PMID:24849349

  6. Sodium leak channel, non-selective contributes to the leak current in human myometrial smooth muscle cells from pregnant women.

    PubMed

    Reinl, Erin L; Cabeza, Rafael; Gregory, Ismail A; Cahill, Alison G; England, Sarah K

    2015-10-01

    Uterine contractions are tightly regulated by the electrical activity of myometrial smooth muscle cells (MSMCs). These cells require a depolarizing current to initiate Ca(2+) influx and induce contraction. Cationic leak channels, which permit a steady flow of cations into a cell, are known to cause membrane depolarization in many tissue types. Previously, a Gd(3+)-sensitive, Na(+)-dependent leak current was identified in the rat myometrium, but the presence of such a current in human MSMCs and the specific ion channel conducting this current was unknown. Here, we report the presence of a Na(+)-dependent leak current in human myometrium and demonstrate that the Na(+)-leak channel, NALCN, contributes to this current. We performed whole-cell voltage-clamp on fresh and cultured MSMCs from uterine biopsies of term, non-laboring women and isolated the leak currents by using Ca(2+) and K(+) channel blockers in the bath solution. Ohmic leak currents were identified in freshly isolated and cultured MSMCs with normalized conductances of 14.6 pS/pF and 10.0 pS/pF, respectively. The myometrial leak current was significantly reduced (P < 0.01) by treating cells with 10 μM Gd(3+) or by superfusing the cells with a Na(+)-free extracellular solution. Reverse transcriptase PCR and immunoblot analysis of uterine biopsies from term, non-laboring women revealed NALCN messenger RNA and protein expression in the myometrium. Notably, ∼90% knockdown of NALCN protein expression with lentivirus-delivered shRNA reduced the Gd(3+)-sensitive leak current density by 42% (P < 0.05). Our results reveal that NALCN, in part, generates the leak current in MSMCs and provide the basis for future research assessing NALCN as a potential molecular target for modulating uterine excitability.

  7. Sodium leak channel, non-selective contributes to the leak current in human myometrial smooth muscle cells from pregnant women

    PubMed Central

    Reinl, Erin L.; Cabeza, Rafael; Gregory, Ismail A.; Cahill, Alison G.; England, Sarah K.

    2015-01-01

    Uterine contractions are tightly regulated by the electrical activity of myometrial smooth muscle cells (MSMCs). These cells require a depolarizing current to initiate Ca2+ influx and induce contraction. Cationic leak channels, which permit a steady flow of cations into a cell, are known to cause membrane depolarization in many tissue types. Previously, a Gd3+-sensitive, Na+-dependent leak current was identified in the rat myometrium, but the presence of such a current in human MSMCs and the specific ion channel conducting this current was unknown. Here, we report the presence of a Na+-dependent leak current in human myometrium and demonstrate that the Na+-leak channel, NALCN, contributes to this current. We performed whole-cell voltage-clamp on fresh and cultured MSMCs from uterine biopsies of term, non-laboring women and isolated the leak currents by using Ca2+ and K+ channel blockers in the bath solution. Ohmic leak currents were identified in freshly isolated and cultured MSMCs with normalized conductances of 14.6 pS/pF and 10.0 pS/pF, respectively. The myometrial leak current was significantly reduced (P < 0.01) by treating cells with 10 μM Gd3+ or by superfusing the cells with a Na+-free extracellular solution. Reverse transcriptase PCR and immunoblot analysis of uterine biopsies from term, non-laboring women revealed NALCN messenger RNA and protein expression in the myometrium. Notably, ∼90% knockdown of NALCN protein expression with lentivirus-delivered shRNA reduced the Gd3+-sensitive leak current density by 42% (P < 0.05). Our results reveal that NALCN, in part, generates the leak current in MSMCs and provide the basis for future research assessing NALCN as a potential molecular target for modulating uterine excitability. PMID:26134120

  8. Effect of high-fat diet on rat myometrium during pregnancy-isolated myometrial mitochondria are not affected.

    PubMed

    Gam, Christiane Marie Bourgin Folke; Mortensen, Ole Hartvig; Qvortrup, Klaus; Damm, Peter; Quistorff, Bjørn

    2015-07-01

    Laboring women with elevated body mass index (BMI) have an increased risk of inefficient uterine labor contractions, and despite the significance of mitochondria in the production of energy to drive uterine contractions, mitochondrial function in the myometrium with reference to the BMI has not been explored. The objective of this study was to determine whether obesity prior to and during gestation affects oxidative capacity and/or morphology of mitochondria in the myometrium at term in an animal model. Rat dams were fed for 47 days prior to impregnation and during gestation with either (1) a regular chow diet, (2) a low-fat high-carbohydrate diet, or (3) a high-fat low-carbohydrate diet (n = 10 in each group). On day 20 of gestation, corresponding to term pregnancy, total hysterectomy was performed with subsequent examination of the function and morphology of myometrial mitochondria. Body composition was regularly assessed by quantitative magnetic resonance imaging, and blood sampling was done prior to diet assignment, impregnation, and hysterectomy. Dams on the high-fat low-carbohydrate diet achieved higher fat percentage compared to rats on the regular chow diet (p < 0.05). Maximal oxygen consumption, phosphate/oxygen ratio, or the amount of mitochondria per gram of myometrium did not differ between the three feeding groups. Electron microscopic examinations did not reveal any morphological differences in mitochondria between groups; however, a previously undescribed subsarcolemmal localization of the mitochondria in the myocyte was identified. We did not find evidence of altered myometrial mitochondrial function or morphology in this animal model of obesity prior to and during pregnancy.

  9. Diagnostic Thresholds for Quantitative REM Sleep Phasic Burst Duration, Phasic and Tonic Muscle Activity, and REM Atonia Index in REM Sleep Behavior Disorder with and without Comorbid Obstructive Sleep Apnea

    PubMed Central

    McCarter, Stuart J.; St. Louis, Erik K.; Duwell, Ethan J.; Timm, Paul C.; Sandness, David J.; Boeve, Bradley F.; Silber, Michael H.

    2014-01-01

    Objectives: We aimed to determine whether phasic burst duration and conventional REM sleep without atonia (RSWA) methods could accurately diagnose REM sleep behavior disorder (RBD) patients with comorbid OSA. Design: We visually analyzed RSWA phasic burst durations, phasic, “any,” and tonic muscle activity by 3-s mini-epochs, phasic activity by 30-s (AASM rules) epochs, and conducted automated REM atonia index (RAI) analysis. Group RSWA metrics were analyzed and regression models fit, with receiver operating characteristic (ROC) curves determining the best diagnostic cutoff thresholds for RBD. Both split-night and full-night polysomnographic studies were analyzed. Setting: N/A. Participants: Parkinson disease (PD)-RBD (n = 20) and matched controls with (n = 20) and without (n = 20) OSA. Interventions: N/A. Measurements and Results: All mean RSWA phasic burst durations and muscle activities were higher in PD-RBD patients than controls (P < 0.0001), and RSWA associations with PD-RBD remained significant when adjusting for age, gender, and REM AHI (P < 0.0001). RSWA muscle activity (phasic, “any”) cutoffs for 3-s mini-epoch scorings were submentalis (SM) (15.5%, 21.6%), anterior tibialis (AT) (30.2%, 30.2%), and combined SM/AT (37.9%, 43.4%). Diagnostic cutoffs for 30-s epochs (AASM criteria) were SM 2.8%, AT 11.3%, and combined SM/AT 34.7%. Tonic muscle activity cutoff of 1.2% was 100% sensitive and specific, while RAI (SM) cutoff was 0.88. Phasic muscle burst duration cutoffs were: SM (0.65) and AT (0.79) seconds. Combining phasic burst durations with RSWA muscle activity improved sensitivity and specificity of RBD diagnosis. Conclusions: This study provides evidence for REM sleep without atonia diagnostic thresholds applicable in Parkinson disease-REM sleep behavior disorder (PD-RBD) patient populations with comorbid OSA that may be useful toward distinguishing PD-RBD in typical outpatient populations. Citation: McCarter SJ, St. Louis EK, Duwell EJ, Timm PC

  10. In vitro comparison of myometrial contractility induced by aglepristone-oxytocin and aglepristone-PGF2alpha combinations at different stages of the estrus cycle in the bitch.

    PubMed

    Gogny, A; Mallem, Y; Destrumelle, S; Thorin, C; Desfontis, J-C; Gogny, M; Fiéni, F

    2010-12-01

    The aim of this in vitro study was to compare the uterokinetic activity of oxytocin and dinoprost, the natural PGF2α, with or without aglepristone, in canine myometrial fibers. Thirty-three bitches were allocated into one of four groups, depending on their estrous stage and whether or not they had received a treatment with aglepristone (metestrus aglepristone, n = 5; metestrus without treatment, n = 9; anestrus aglepristone, n = 9; anestrus without treatment, n = 10). After hysterectomy, longitudinal and circular uterine strips were mounted in organ baths. Oxytocin or PGF2α (10 nmol/l to 10 micromol/l) were applied non-cumulatively. A linear mixed effects models theory was used to compare the fiber effect, the aglepristone effect, and the treatment effect, from the area under the curves calculated from the contractile effect/concentration curves for each drug. Oxytocin and PGF2α induced concentration-dependent myometrial contractions in longitudinal (LF) and circular myometrial fibers (CF), indicating the presence of functional contractile oxytocin- and PGF2α-receptors in metestrus and anestrus. The contractile response to oxytocin was greater in LF than in CF in all of the groups; the response to PGF2α was greater in LF than in CF in non-treated bitches in anestrus and in treated bitches in metestrus. These results suggest that there is a difference in sensitivity or a heterogeneous distribution of oxytocin and PGF2α-receptors in the myometrial layers, which is independent of hormonal impregnation. The contractile response to oxytocin and PGF2α was significantly increased after aglepristone treatment in LF during metestrus, suggesting that the progesterone withdrawal induced by aglepristone has a role to play. The longitudinal myometrial layer also appeared to be the target for the two drugs at this stage. This study provides new information about canine uterine contractile activity, notably the differing behavior of myometrial CF and LF; in vivo studies

  11. Deep brain stimulation suppresses pallidal low frequency activity in patients with phasic dystonic movements.

    PubMed

    Barow, Ewgenia; Neumann, Wolf-Julian; Brücke, Christof; Huebl, Julius; Horn, Andreas; Brown, Peter; Krauss, Joachim K; Schneider, Gerd-Helge; Kühn, Andrea A

    2014-11-01

    Deep brain stimulation of the globus pallidus internus alleviates involuntary movements in patients with dystonia. However, the mechanism is still not entirely understood. One hypothesis is that deep brain stimulation suppresses abnormally enhanced synchronized oscillatory activity within the motor cortico-basal ganglia network. Here, we explore deep brain stimulation-induced modulation of pathological low frequency (4-12 Hz) pallidal activity that has been described in local field potential recordings in patients with dystonia. Therefore, local field potentials were recorded from 16 hemispheres in 12 patients undergoing deep brain stimulation for severe dystonia using a specially designed amplifier allowing simultaneous high frequency stimulation at therapeutic parameter settings and local field potential recordings. For coherence analysis electroencephalographic activity (EEG) over motor areas and electromyographic activity (EMG) from affected neck muscles were recorded before and immediately after cessation of high frequency stimulation. High frequency stimulation led to a significant reduction of mean power in the 4-12 Hz band by 24.8 ± 7.0% in patients with predominantly phasic dystonia. A significant decrease of coherence between cortical EEG and pallidal local field potential activity in the 4-12 Hz range was revealed for the time period of 30 s after switching off high frequency stimulation. Coherence between EMG activity and pallidal activity was mainly found in patients with phasic dystonic movements where it was suppressed after high frequency stimulation. Our findings suggest that high frequency stimulation may suppress pathologically enhanced low frequency activity in patients with phasic dystonia. These dystonic features are the quickest to respond to high frequency stimulation and may thus directly relate to modulation of pathological basal ganglia activity, whereas improvement in tonic features may depend on long-term plastic changes within the

  12. Primary Human Uterine Leiomyoma Cell Culture Quality Control: Some Properties of Myometrial Cells Cultured under Serum Deprivation Conditions in the Presence of Ovarian Steroids

    PubMed Central

    Sumikawa, Joana Tomomi; Batista, Fabrício Pereira; Paredes-Gamero, Edgar J.; Girão, Manoel J. B. C.; Oliva, Maria Luiza V.

    2016-01-01

    Cell culture is considered the standard media used in research to emulate the in vivo cell environment. Crucial in vivo experiments cannot be conducted in humans and depend on in vitro methodologies such as cell culture systems. However, some procedures involving the quality control of cells in culture have been gradually neglected by failing to acknowledge that primary cells and cell lines change over time in culture. Thus, we report methods based on our experience for monitoring primary cell culture of human myometrial cells derived from uterine leiomyoma. We standardized the best procedure of tissue dissociation required for the study of multiple genetic marker systems that include species-specific antigens, expression of myofibroblast or myoblast markers, growth curve, serum deprivation, starvation by cell cycle synchronization, culture on collagen coated plates, and 17 β-estradiol (E2) and progesterone (P4) effects. The results showed that primary myometrial cells from patients with uterine leiomyoma displayed myoblast phenotypes before and after in vitro cultivation, and leiomyoma cells differentiated into mature myocyte cells under the appropriate differentiation-inducing conditions (serum deprivation). These cells grew well on collagen coated plates and responded to E2 and P4, which may drive myometrial and leiomyoma cells to proliferate and adhere into a focal adhesion complex involvement in a paracrine manner. The establishment of these techniques as routine procedures will improve the understanding of the myometrial physiology and pathogenesis of myometrium-derived diseases such as leiomyoma. Mimicking the in vivo environment of fibrotic conditions can prevent false results and enhance results that are based on cell culture integrity. PMID:27391384

  13. Clinical Outcomes in International Federation of Gynecology and Obstetrics Stage IA Endometrial Cancer With Myometrial Invasion Treated With or Without Postoperative Vaginal Brachytherapy

    SciTech Connect

    Diavolitsis, V.; Rademaker, A.; Lurain, J.; Hoekstra, A.; Strauss, J.; Small, W.

    2012-10-01

    Purpose: To assess the clinical outcomes of patients with Stage IA endometrial cancer with myometrial invasion treated with postoperative vaginal brachytherapy (VBT) with those who received no adjuvant therapy (NAT). Methods and Materials: All patients treated with hysterectomy for endometrial cancer at Northwestern Memorial Hospital between 1978 and 2005 were identified. Those patients with Stage IA disease with myometrial invasion who were treated with VBT alone or NAT were identified and included in the present analysis. Results: Of 252 patients with Stage IA endometrial cancer with superficial (<50%) myometrial invasion who met the inclusion criteria, 169 underwent VBT and 83 received NAT. The median follow-up in the VBT and NAT groups was 103 and 61 months, respectively. In the VBT group, 56.8% had Grade 1, 37.9% had Grade 2, and 5.3% had Grade 3 tumors. In the NAT group, 75.9%, 20.5%, and 3.6% had Grade 1, 2, and 3 tumors, respectively. Lymphatic or vascular space invasion was noted in 12.4% of the VBT patients and 5.6% of the NAT patients. The 5-year overall survival rate was 95.5%. The 5-year recurrence-free survival rate was 92.4% for all patients, 94.4% for the VBT group, and 87.4% for the NAT group (p = NS). Of the 169 VBT patients and 83 NAT patients, 8 (4.7%) and 6 (7.2%) developed recurrent disease. One vaginal recurrence occurred in the VBT group (0.6%) and three in the NAT group (3.8%). Recurrences developed 2-102 months after surgical treatment. Two of the four vaginal recurrences were salvaged. No Grade 3 or higher acute or late radiation toxicity was noted. Conclusions: The use of postoperative VBT in patients with Stage I endometrial cancer with <50% myometrial invasion yielded excellent vaginal disease control and disease-free survival, with minimal toxicity.

  14. The GABAA antagonist DPP-4-PIOL selectively antagonises tonic over phasic GABAergic currents in dentate gyrus granule cells.

    PubMed

    Boddum, Kim; Frølund, Bente; Kristiansen, Uffe

    2014-11-01

    GABAA receptors mediate two different types of inhibitory currents: phasic inhibitory currents when rapid and brief presynaptic GABA release activates postsynaptic GABAA receptors and tonic inhibitory currents generated by low extrasynaptic GABA levels, persistently activating extrasynaptic GABAA receptors. The two inhibitory current types are mediated by different subpopulations of GABAA receptors with diverse pharmacological profiles. Selective antagonism of tonic currents is of special interest as excessive tonic inhibition post-stroke has severe pathological consequences. Here we demonstrate that phasic and tonic GABAA receptor currents can be selectively inhibited by the antagonists SR 95531 and the 4-PIOL derivative, 4-(3,3-diphenylpropyl)-5-(4-piperidyl)-3-isoxazolol hydrobromide (DPP-4-PIOL), respectively. In dentate gyrus granule cells, SR 95531 was found approximately 4 times as potent inhibiting phasic currents compared to tonic currents (IC50 values: 101 vs. 427 nM). Conversely, DPP-4-PIOL was estimated to be more than 20 times as potent inhibiting tonic current compared to phasic current (IC50 values: 0.87 vs. 21.3 nM). Consequently, we were able to impose a pronounced reduction in tonic GABA mediated current (>70 %) by concentrations of DPP-4-PIOL, at which no significant effect on the phasic current was seen. Our findings demonstrate that selective inhibition of GABA mediated tonic current is possible, when targeting a subpopulation of GABAA receptors located extrasynaptically using the antagonist, DPP-4-PIOL. PMID:25103229

  15. Phasic acetylcholine release and the volume transmission hypothesis: time to move on

    PubMed Central

    Sarter, Martin; Parikh, Vinay; Howe, W. Matthew

    2009-01-01

    Traditional descriptions of the cortical cholinergic input system focused on the diffuse organization of cholinergic projections and the hypothesis that slowly changing levels of extracellular acetylcholine (ACh) mediate different arousal states. The ability of ACh to reach the extrasynaptic space (volume neurotransmission), as opposed to remaining confined to the synaptic cleft (wired neurotransmission), has been considered an integral component of this conceptualization. Recent studies demonstrated that phasic release of ACh, at the scale of seconds, mediates precisely defined cognitive operations. This characteristic of cholinergic neurotransmission is proposed to be of primary importance for understanding cholinergic function and developing treatments for cognitive disorders that result from abnormal cholinergic neurotransmission. PMID:19377503

  16. Activation of the motor cortex during phasic rapid eye movement sleep

    PubMed Central

    De Carli, Fabrizio; Proserpio, Paola; Morrone, Elisa; Sartori, Ivana; Ferrara, Michele; Gibbs, Steve Alex; De Gennaro, Luigi; Lo Russo, Giorgio

    2016-01-01

    When dreaming during rapid eye movement (REM) sleep, we can perform complex motor behaviors while remaining motionless. How the motor cortex behaves during this state remains unknown. Here, using intracerebral electrodes sampling the human motor cortex in pharmacoresistant epileptic patients, we report a pattern of electroencephalographic activation during REM sleep similar to that observed during the performance of a voluntary movement during wakefulness. This pattern is present during phasic REM sleep but not during tonic REM sleep, the latter resembling relaxed wakefulness. This finding may help clarify certain phenomenological aspects observed in REM sleep behavior disorder. Ann Neurol 2016;79:326–330 PMID:26575212

  17. Phasic dopamine signals: from subjective reward value to formal economic utility

    PubMed Central

    Schultz, Wolfram; Carelli, Regina M; Wightman, R Mark

    2015-01-01

    Although rewards are physical stimuli and objects, their value for survival and reproduction is subjective. The phasic, neurophysiological and voltammetric dopamine reward prediction error response signals subjective reward value. The signal incorporates crucial reward aspects such as amount, probability, type, risk, delay and effort. Differences of dopamine release dynamics with temporal delay and effort in rodents may derive from methodological issues and require further study. Recent designs using concepts and behavioral tools from experimental economics allow to formally characterize the subjective value signal as economic utility and thus to establish a neuronal value function. With these properties, the dopamine response constitutes a utility prediction error signal. PMID:26719853

  18. Forkhead box O1 (FOXO1) in pregnant human myometrial cells: a role as a pro-inflammatory mediator in human parturition.

    PubMed

    Lappas, Martha

    2013-09-01

    Prematurity is the most important complication contributing to neonatal morbidity and mortality. It is the untimely activation of the terminal events of human parturition that lead to preterm birth, with inflammation playing a driving role in initiating uterine contractions. The purpose of this study was to investigate the role of Forkhead box O1 (FOXO1), a pro-inflammatory modulator, during human parturition. FOXO1 mRNA expression was quantified using qRT-PCR, and protein expression using Western blotting in myometrial biopsies from pregnant non-labouring and labouring women at term. In addition, the effect of FOXO1 knockdown in human myometrial cells on IL-β-stimulated expression of pro-inflammatory mediators was investigated. Levels of FOXO1, at both the gene and protein levels, were higher in myometrium obtained from women in labour compared with samples taken from non-labouring women. FOXO1 deletion in myometrial cells attenuated the capacity of IL-1β to induce inflammatory gene expression. Specifically, FOXO1 knockdown significantly decreased IL-1β-induced IL-6 and IL-8 expression; production and COX-2 expression and subsequent prostaglandin (PGE2 and PGF2α) release; and MMP-9 mRNA expression and activity. In summary, this study demonstrates for the first time the potential role of FOXO1 inflammatory events of both physiological and pathological labour in human myometrium, and may provide a therapeutic target in the management of preterm labour.

  19. The Pattern of Myometrial Invasion As a Predictor of Lymph Node Metastasis or Extrauterine Disease in Low Grade Endometrial Carcinoma

    PubMed Central

    Euscher, Elizabeth; Fox, Patricia; Bassett, Roland; Al-Ghawi, Hayma; Ali-Fehmi, Rouba; Barbuto, Denise; Djordjevic, Bojana; Frauenhoffer, Elizabeth; Kim, Insun; Hong, Sun Rang; Montiel, Delia; Moschiano, Elizabeth; Roma, Andres; Silva, Elvio; Malpica, Anais

    2013-01-01

    The purpose of this study was to examine predictors of lymph node metastases (LN+) or extrauterine disease (ED) in low grade (FIGO grades 1 or 2) endometrioid carcinoma (LGEC) in a multi institutional setting. For LGEC with and without LNM or ED, each of the 9 participating institutions evaluated patients age, tumor size, myometrial invasion (MI), FIGO grade, % solid component, the presence or absence of papillary architecture, microcystic elongated and fragmented glands (MELF) and single cell/cell cluster invasion (SCI), lymphovascular invasion (LVI), lower uterine segment (LUS) and cervical stromal (CX) involvement and numbers of pelvic (PLN) and para-aortic (PALN) LNs sampled.302 cases were reviewed: LN+ or ED +, 96; LN-/ED-, 208. Patients' ages ranged from 23-91 yrs (median 61). Table 1 summarizes the histopathologic variables that were noted for the LN+ or ED+ group: tumor size ≥2cm, 93/96 (97%), MI >50%, 54/96 (56%), MELF, 67/96 (70%), SCI, 33/96 (34%), LVI, 79/96 (82%), >20% solid, 65/96 (68%), papillary architecture present, 68/96 (72%), LUS involved, 64/96 (67%) and CX involved, 31/96 (32%). For the LN-/ED- group, the results were as follows: tumor size ≥2cm, 152/208 (73%), MI >50%, 56/208 (27%), MELF, 79/208 (38%), single cell invasion, 19/208 (9%) , LVI, 56/208 (27%), >20% solid, 160/208 (77%), papillary architecture present, 122/208 (59%), LUS involved, 77/208 (37%), CX involved, 31/208 (15%). There was no evidence of a difference in the number of pelvic or para-aortic LNs sampled between groups (p=0.9 and 0.1, respectively). Following multivariate analysis, depth of myometrial invasion, cervical stromal involvement, lymphovascular space invasion, and the single cell pattern of invasion emerged as significant predictors of advanced stage disease. Although univariate analysis pointed to LUS involvement, MELF pattern of invasion, and papillary architecture as possible predictors of advanced stage disease, these were not shown to be significant by

  20. Tonic and phasic activation and arousal effects as a function of feedback in repetitive-choice reaction time tasks.

    PubMed

    De Brabander, Bert; Declerck, Carolyn H; Boone, Christophe

    2002-06-01

    This study examines the effects of positive and negative feedback on performance during choice reaction time tasks to assess whether they differentially affect phasic arousal and tonic activation. Participants (N = 96) received either no feedback or signals of reward, punishment, or both during a semantic and a visuospatial repetitive-choice reaction time task. The number of errors made was analyzed both on a trial-by-trial basis and over a continuous series of 80 trials (assessing phasic and tonic feedback effects, respectively). The results show that punishment and reward have different phasic and tonic effects on performance. The data further show that feedback effects interact with the task characteristics: semantic versus visuospatial, and reaction stimulus preceded by a warning signal versus an irrelevant signal. The interaction effects appear to be consistent with the proposed neurological model.

  1. Covariation of phasic cortical and cardiovascular responses in a detection task.

    PubMed

    van der Veen, F M; Mulder, L J; Hoekzema, A; Mulder, G

    1996-10-31

    The relationship between cardiovascular and cortical responses was examined in an experiment in which subjects performed a detection task and a simple reference task. The detection task was developed according to Skinner et al., (1987). Cortical activity was examined with event related brain potentials (ERPs). ERPs revealed more cortical activation during detection task blocks. Both tonic and phasic measures of cardiovascular activity were derived. Tonic measures were heart rate (HR), systolic blood pressure (SBP). T-wave amplitude (TWA), respiration linked HR-variability and a measure for baroreflex sensitivity. These measures revealed no important differences between the reference task and detection task blocks. Phasic cardiovascular measures were evoked HR, SBP and TWA. Evoked HR showed a larger deceleration and evoked SBP showed a smaller decrease on detection task blocks. Evoked TWA did not differentiate between both types of task. It is concluded that an adjusted version of the fronto-cortical control hypothesis of Skinner could best account for the data. PMID:8913524

  2. Phasic Mesolimbic Dopamine Signaling Encodes the Facilitation of Incentive Motivation Produced by Repeated Cocaine Exposure

    PubMed Central

    Ostlund, Sean B; LeBlanc, Kimberly H; Kosheleff, Alisa R; Wassum, Kate M; Maidment, Nigel T

    2014-01-01

    Drug addiction is marked by pathological drug seeking and intense drug craving, particularly in response to drug-related stimuli. Repeated psychostimulant administration is known to induce long-term alterations in mesolimbic dopamine (DA) signaling that are hypothesized to mediate this heightened sensitivity to environmental stimuli. However, there is little direct evidence that drug-induced alteration in mesolimbic DA function underlies this hypersensitivity to motivational cues. In the current study, we tested this hypothesis using fast-scan cyclic voltammetry to monitor phasic DA signaling in the nucleus accumbens core of cocaine-pretreated (6 once-daily injections of 15 mg/kg, i.p.) and drug-naive rats during a test of cue-evoked incentive motivation for food—the Pavlovian-to-instrumental transfer task. We found that prior cocaine exposure augmented both reward seeking and DA release triggered by the presentation of a reward-paired cue. Furthermore, cue-evoked DA signaling positively correlated with cue-evoked food seeking and was found to be a statistical mediator of this behavioral effect of cocaine. Taken together, these findings provide support for the hypothesis that repeated cocaine exposure enhances cue-evoked incentive motivation through augmented phasic mesolimbic DA signaling. This work sheds new light on a fundamental neurobiological mechanism underlying motivated behavior and its role in the expression of compulsive reward seeking. PMID:24804846

  3. Shift from phasic to tonic GABAergic transmission following laser-lesions in the rat visual cortex.

    PubMed

    Imbrosci, Barbara; Neubacher, Ute; White, Robin; Eysel, Ulf T; Mittmann, Thomas

    2013-06-01

    Reduction in the strength of GABAergic neurotransmission has often been reported following brain lesions. This weakened inhibition is believed to influence neurological deficits, neuronal hyperexcitability and functional recovery after brain injuries. Uncovering the mechanisms underlying the altered inhibition is therefore crucial. In the present study we used an ex vivo-in vitro model of laser lesions in the rat visual cortex to characterize the cellular correlates of changes in GABAergic transmission in the tissue adjacent to the injury. In the first week post-injury the number of VGAT positive GABAergic terminals as well as the expression level of the GABA synthesizing enzymes GAD67 and GAD65 remained unaltered. However, a reduced frequency of miniature inhibitory postsynaptic currents (mIPSCs) together with an increased paired-pulse ratio (PPR) of evoked IPSCs suggested a functional reduction of phasic GABA release. In parallel, we found an enhancement in the GABAA receptor-mediated tonic inhibition. On the basis of these findings, we propose that cortical lesions provoke a shift in GABAergic transmission, decreasing the phasic and reinforcing the tonic component. We therefore suggest that it is not, as traditionally assumed, the overall inhibitory strength to be primarily compromised by a cortical lesion but rather the temporal accuracy of the GABAergic synaptic signaling. PMID:23224682

  4. Neural Mechanisms Supporting Acquired Phasic Dopamine Responses in Learning: An Integrative Synthesis

    PubMed Central

    Hazy, Thomas E.; Frank, Michael J.; O’Reilly, Randall C.

    2010-01-01

    What biological mechanisms underlie the reward-predictive firing properties of midbrain dopaminergic neurons, and how do they relate to the complex constellation of empirical findings understood as Pavlovian and instrumental conditioning? We previously presented PVLV, a biologically-inspired Pavlovian learning algorithm accounting for DA activity in terms of two interrelated systems: a primary value (PV) system, which governs how DA cells respond to a US (reward) and; a learned value (LV) system, which governs how DA cells respond to a CS. Here, we provide a more extensive review of the biological mechanisms supporting phasic DA firing and their relation to the spate of Pavlovian conditioning phenomena and their sensitivity to focal brain lesions. We further extend the model by incorporating a new NV (novelty value) component reflecting the ability of novel stimuli to trigger phasic DA firing, providing “novelty bonuses” which encourages exploratory working memory updating and in turn speeds learning in trace conditioning and other working memory-dependent paradigms. The evolving PVLV model builds upon insights developed in many earlier computational models, especially reinforcement learning models based on the ideas of Sutton and Barto, biological models, and the psychological model developed by Savastano and Miller. The PVLV framework synthesizes these various approaches, overcoming important shortcomings of each by providing a coherent and specific mapping to much of the relevant empirical data at both the micro- and macro-levels, and examines their relevance for higher order cognitive functions. PMID:19944716

  5. Role of SM22 in the differential regulation of phasic vs. tonic smooth muscle.

    PubMed

    Rattan, Satish; Ali, Mehboob

    2015-04-01

    Preliminary proteomics studies between tonic vs. phasic smooth muscles identified three distinct protein spots identified to be those of transgelin (SM22). The latter was found to be distinctly downregulated in the internal anal sphincter (IAS) vs. rectal smooth muscle (RSM) SMC. The major focus of the present studies was to examine the differential molecular control mechanisms by SM22 in the functionality of truly tonic smooth muscle of the IAS vs. the adjoining phasic smooth muscle of the RSM. We monitored SMC lengths before and after incubation with pFLAG-SM22 (for SM22 overexpression), and SM22 small-interfering RNA. pFLAG-SM22 caused concentration-dependent and significantly greater relaxation in the IAS vs. the RSM SMCs. Conversely, temporary silencing of SM22 caused contraction in both types of the SMCs. Further studies revealed a significant reverse relationship between the levels of SM22 phosphorylation and the amount of SM22-actin binding in the IAS and RSM SMC. Data showed higher phospho-SM22 levels and decreased SM22-actin binding in the IAS, and reverse to be the case in the RSM SMCs. Experiments determining the mechanism for SM22 phosphorylation in these smooth muscles revealed that Y-27632 (Rho kinase inhibitor) but not Gö-6850 (protein kinase C inhibitor) caused concentration-dependent decreased phosphorylation of SM22. We speculate that SM22 plays an important role in the regulation of basal tone via Rho kinase-induced phosphorylation of SM22.

  6. Repeatability of phasic muscle activity: performance of surface and intramuscular wire electrodes in gait analysis.

    PubMed

    Kadaba, M P; Wootten, M E; Gainey, J; Cochran, G V

    1985-01-01

    Repeatability is an important consideration for gait analysis data that are being used as an adjunct to clinical decision making. An index of repeatability may be based on a statistical criterion (variance ratio) that reflects similarity of wave forms over a number of identical cycles. The purpose of this study was to use the variance ratio to assess the repeatability of phasic muscle activity recorded with surface and bipolar intramuscular wire electrodes during gait on 10 normal subjects. Variance ratios were calculated using rectified and smoothed electromyographic data recorded simultaneously from the two types of electrodes. Three measures of repeatability (reproducibility, reliability, and constancy--defined as the cycle-to-cycle, run-to-run, and day-to-day repeatability of phasic muscle activity) were used to compare the performance of the two electrode techniques. Results show that the reproducibility and reliability were better for surface electrodes than for intramuscular wire electrodes, and constancy was good for surface electrodes and poor for intramuscular wire electrodes. Repeatability improved with increasing smoothing window lengths but was better for surface electrodes than wire electrodes, irrespective of the smoothing window. This study indicates that surface electrode data represent a more consistent measure of activity of superficial muscles, if comparisons are to be made between gait data from different test days.

  7. Temporal expectancy modulates phasic alerting in both detection and discrimination tasks.

    PubMed

    Lu, Shena; Wang, Wei; Cai, Yongchun

    2015-02-01

    The aim of the present study was to investigate whether phasic alerting might be modulated by temporal expectancy and to determine the processing stages at which this modulation might occur. We manipulated participants' expectancy for the target appearance by systematically varying the cue-target stimulus onset asynchrony (SOA) distribution in both detection and discrimination tasks. There were three temporal expectancy conditions: the non-aging condition in which temporal expectancy was eliminated, the aging condition in which temporal expectancy increased as SOA increased, and the accelerated-aging condition in which temporal expectancy increased more dramatically as SOA increased than in the aging condition. We obtained the same pattern of results in both detection and discrimination tasks: the onset time of the alerting effect was postponed successively across the three temporal expectancy conditions. The present findings suggest that the time course of the alerting effect may be modulated by temporal expectancy, highlighting the importance of taking account into the influence of temporal expectancy in studies involving the time course of cognitive processes. Furthermore, since mechanisms underlying the detection and discrimination tasks may differ in early processing stages involving perceptual analysis and response selection, the same result pattern observed in both tasks is consistent with the hypothesis that the modulation of temporal expectancy on phasic alerting occurs at late processing stages involving motor preparation.

  8. Ghrelin acts as an interface between physiological state and phasic dopamine signaling.

    PubMed

    Cone, Jackson J; McCutcheon, James E; Roitman, Mitchell F

    2014-04-01

    Brief, high-concentration (phasic) spikes in nucleus accumbens dopamine critically participate in aspects of food reward. Although physiological state (e.g., hunger, satiety) and associated hormones are known to affect dopamine tone in general, whether they modulate food-evoked, phasic dopamine specifically is unknown. Here, we used fast-scan cyclic voltammetry in awake, behaving rats to record dopamine spikes evoked by delivery of sugar pellets while pharmacologically manipulating central receptors for the gut "hunger" hormone ghrelin. Lateral ventricular (LV) ghrelin increased, while LV ghrelin receptor antagonism suppressed the magnitude of dopamine spikes evoked by food. Ghrelin was effective when infused directly into the lateral hypothalamus (LH), but not the ventral tegmental area (VTA). LH infusions were made in close proximity to orexin neurons, which are regulated by ghrelin and project to the VTA. Thus, we also investigated and found potentiation of food-evoked dopamine spikes by intra-VTA orexin-A. Importantly, intra-VTA blockade of orexin receptors attenuated food intake induced by LV ghrelin, thus establishing a behaviorally relevant connection between central ghrelin and VTA orexin. Further analysis revealed that food restriction increased the magnitude of dopamine spikes evoked by food independent of any pharmacological manipulations. The results support the regulation of food-evoked dopamine spikes by physiological state with endogenous fluctuations in ghrelin as a key contributor. Our data highlight a novel mechanism by which signals relating physiological state could influence food reinforcement and food-directed behavior. PMID:24695709

  9. Affinity for MgADP and force of unbinding from actin of myosin purified from tonic and phasic smooth muscle

    PubMed Central

    Léguillette, Renaud; Zitouni, Nedjma B.; Govindaraju, Karuthapillai; Fong, Laura M.; Lauzon, Anne-Marie

    2008-01-01

    Smooth muscle is unique in its ability to maintain force at low MgATP consumption. This property, called the latch state, is more prominent in tonic than phasic smooth muscle. Studies performed at the muscle strip level have suggested that myosin from tonic muscle has a greater affinity for MgADP and therefore remains attached to actin longer than myosin from phasic muscle, allowing for cross-bridge dephosphorylation and latch-bridge formation. An alternative hypothesis is that after dephosphorylation, myosin reattaches to actin and maintains force. We investigated these fundamental properties of smooth muscle at the molecular level. We used an in vitro motility assay to measure actin filament velocity (νmax) when propelled by myosin purified from phasic or tonic muscle at increasing [MgADP]. Myosin was 25% thiophosphorylated and 75% unphosphorylated to approximate in vivo conditions. The slope of νmax versus [MgADP] was significantly greater for tonic (−0.51 ± 0.04) than phasic muscle myosin (−0.15 ± 0.04), demonstrating the greater MgADP affinity of myosin from tonic muscle. We then used a laser trap assay to measure the unbinding force from actin of populations of unphosphorylated tonic and phasic muscle myosin. Both myosin types attached to actin, and their unbinding force (0.092 ± 0.022 pN for phasic muscle and 0.084 ± 0.017 pN for tonic muscle) was not statistically different. We conclude that the greater affinity for MgADP of tonic muscle myosin and the reattachment of dephosphorylated myosin to actin may both contribute to the latch state. PMID:18614813

  10. Contribution of coupling between human myometrial beta2-adrenoreceptor and the BK(Ca) channel to uterine quiescence.

    PubMed

    Chanrachakul, Boonsri; Broughton Pipkin, Fiona; Khan, Raheela N

    2004-12-01

    The beta(2)-adrenergic receptor (beta(2)-AR) and the large-conductance Ca(2+)-activated K(+) (BK(Ca)) channel have been shown, separately, to be involved in mediating uterine relaxation. Our recent studies reveal that the levels of both beta(2)-AR and BK(Ca) channel proteins in pregnant human myometrium decrease by approximately 50% after the onset of labor. We present direct evidence in support of a structural and functional association between the beta(2)-AR and the BK(Ca) channel in pregnant human myometrium. Localization of both proteins is predominantly plasmalemmal, with 60% of beta(2)-AR colocalizing with the BK(Ca) channel. Coimmunoprecipitation studies indicate that BK(Ca) and beta(2)-AR are structurally linked by direct protein-protein interactions. Functional correlation was confirmed by experiments of human myometrial contractility in which the BK(Ca) channel blocker, paxilline, significantly antagonized the relaxant effect of the beta(2)-AR agonist ritodrine. These novel findings provide an insight into the coupling between the beta(2)-AR and BK(Ca) channel and may have utility in the application of this signaling cascade for therapeutic potential in the management of preterm labor.

  11. A Specific Component of the Evoked Potential Mirrors Phasic Dopamine Neuron Activity during Conditioning.

    PubMed

    Pan, Wei-Xing; Dudman, Joshua T

    2015-07-22

    Midbrain dopamine (DA) neurons are thought to be a critical node in the circuitry that mediates reward learning. DA neurons receive diverse inputs from regions distributed throughout the neuraxis from frontal neocortex to the mesencephalon. While a great deal is known about changes in the activity of individual DA neurons during learning, much less is known about the functional changes in the microcircuits in which DA neurons are embedded. Here we used local field potentials recorded from the midbrain of behaving mice to show that the midbrain evoked potential (mEP) faithfully reflects the temporal and spatial structure of the phasic response of midbrain neuron populations during conditioning. By comparing the mEP to simultaneously recorded single units, we identified specific components of the mEP that corresponded to phasic DA and non-DA responses to salient stimuli. The DA component of the mEP emerged with the acquisition of a conditioned stimulus, was extinguished following changes in reinforcement contingency, and could be inhibited by pharmacological manipulations that attenuate the phasic responses of DA neurons. In contrast to single-unit recordings, the mEP permitted relatively dense sampling of the midbrain circuit during conditioning and thus could be used to reveal the spatiotemporal structure of multiple intermingled midbrain circuits. Finally, the mEP response was stable for months and thus provides a new approach to study long-term changes in the organization of ventral midbrain microcircuits during learning. Significance statement: Neurons that synthesize and release the neurotransmitter dopamine play a critical role in voluntary reward-seeking behavior. Much of our insight into the function of dopamine neurons comes from recordings of individual cells in behaving animals; however, it is notoriously difficult to record from dopamine neurons due to their sparsity and depth, as well as the presence of intermingled non-dopaminergic neurons. Here we

  12. Orienting, emotion, and memory: phasic and tonic variation in heart rate predicts memory for emotional pictures in men.

    PubMed

    Abercrombie, Heather C; Chambers, Andrea S; Greischar, Lawrence; Monticelli, Roxanne M

    2008-11-01

    Arousal-related processes associated with heightened heart rate (HR) predict memory enhancement, especially for emotionally arousing stimuli. In addition, phasic HR deceleration reflects "orienting" and sensory receptivity during perception of stimuli. We hypothesized that both tonic elevations in HR as well as phasic HR deceleration during viewing of pictures would be associated with deeper encoding and better subsequent memory for stimuli. Emotional pictures are more memorable and cause greater HR deceleration than neutral pictures. Thus, we predicted that the relations between cardiac activity and memory enhancement would be most pronounced for emotionally-laden compared to neutral pictures. We measured HR in 53 males during viewing of unpleasant, neutral, and pleasant pictures, and tested memory for the pictures two days later. Phasic HR deceleration during viewing of individual pictures was greater for subsequently remembered than forgotten pictures across all three emotion categories. Elevated mean HR across the entire encoding epoch also predicted better memory performance, but only for emotionally arousing pictures. Elevated mean HR and phasic HR deceleration were associated, such that individuals with greater tonic HR also showed greater HR decelerations during picture viewing, but only for emotionally arousing pictures. Results suggest that tonic elevations in HR are associated both with greater orienting and heightened memory for emotionally arousing stimuli.

  13. Elevated PEM (Phasic Electromyographic Metric) Rates Identify Rapid Eye Movement Behavior Disorder Patients on Nights Without Behavioral Abnormalities

    PubMed Central

    Bliwise, Donald L.; Rye, David B.

    2008-01-01

    Objective: To determine the validity of the phasic electromyographic metric (PEM) to differentiate patients with a history suggestive of rapid eye movement behavior disorder (REMBD) on laboratory nights without overt dream-enactment behavior. Methods: PEM was quantified as the % of 2.5-sec intervals with phasic muscle activity of 100-msec duration with an amplitude of at least 4 times background activity in 11 patients and 31 elderly controls. Data were derived from both REM and NREM sleep from 5 muscle groups (mentalis, left/right anterior tibialis, left/right brachioradialis). Results: Relative to controls, REMBD patients had significantly higher levels of PEM activity in all recordings. The largest differences occurred during REM sleep for the mentalis and brachioradialis channels. Similar results were obtained by limiting quantification of PEM to the final REM period of the night and could be accomplished by individuals with no previous familiarity with polysomnography. Discussion: PEM may be a useful metric to characterize the REM related phasic muscle activity on patients with a history of REMBD, even when no overt dream-enactment behaviors are detected on a laboratory night. Citation: Bliwise DL; Rye DB. Elevated PEM (phasic electromyographic metric) rates identify rapid eye movement behavior disorder patients on nights without behavioral abnormalities. SLEEP 2008;31(6):853–857. PMID:18548830

  14. Affect Intensity and Phasic REM Sleep in Depressed Men before and after Treatment with Cognitive-Behavioral Therapy.

    ERIC Educational Resources Information Center

    Nofzinger, Eric A.; And Others

    1994-01-01

    Explored relationship between daytime affect and REM (rapid eye movement) sleep in 45 depressed men before and after treatment with cognitive-behavioral therapy and in control group of 43 healthy subjects. For depressed subjects only, intensity of daytime affect correlated significantly and positively with phasic REM sleep measures at pre- and…

  15. Excessive cocaine use results from decreased phasic dopamine signaling in the striatum

    PubMed Central

    Willuhn, Ingo; Burgeno, Lauren M.; Groblewski, Peter A.; Phillips, Paul E. M.

    2014-01-01

    Drug addiction is a neuropsychiatric disorder marked by escalating drug use. Dopamine neurotransmission in the ventromedial striatum (VMS) mediates acute reinforcing effects of abused drugs, but with protracted use the dorsolateral striatum (DLS) is thought to assume control over drug seeking. We measured striatal dopamine release during a cocaine self-administration regimen that produced escalation of drug taking in rats. Surprisingly, we found that phasic dopamine decreased in both regions as the rate of cocaine intake increased; with the decrement in dopamine in the VMS significantly correlated with the rate of escalation. Administration of the dopamine precursor L-DOPA at a dose that replenished dopamine signaling in the VMS reversed escalation, thereby demonstrating the causal relationship between diminished dopamine transmission and excessive drug use. Thus, together these data provide mechanistic and therapeutic insight into the excessive drug intake that emerges following protracted use. PMID:24705184

  16. Tamping Ramping: Algorithmic, Implementational, and Computational Explanations of Phasic Dopamine Signals in the Accumbens.

    PubMed

    Lloyd, Kevin; Dayan, Peter

    2015-12-01

    Substantial evidence suggests that the phasic activity of dopamine neurons represents reinforcement learning's temporal difference prediction error. However, recent reports of ramp-like increases in dopamine concentration in the striatum when animals are about to act, or are about to reach rewards, appear to pose a challenge to established thinking. This is because the implied activity is persistently predictable by preceding stimuli, and so cannot arise as this sort of prediction error. Here, we explore three possible accounts of such ramping signals: (a) the resolution of uncertainty about the timing of action; (b) the direct influence of dopamine over mechanisms associated with making choices; and (c) a new model of discounted vigour. Collectively, these suggest that dopamine ramps may be explained, with only minor disturbance, by standard theoretical ideas, though urgent questions remain regarding their proximal cause. We suggest experimental approaches to disentangling which of the proposed mechanisms are responsible for dopamine ramps. PMID:26699940

  17. Tamping Ramping: Algorithmic, Implementational, and Computational Explanations of Phasic Dopamine Signals in the Accumbens.

    PubMed

    Lloyd, Kevin; Dayan, Peter

    2015-12-01

    Substantial evidence suggests that the phasic activity of dopamine neurons represents reinforcement learning's temporal difference prediction error. However, recent reports of ramp-like increases in dopamine concentration in the striatum when animals are about to act, or are about to reach rewards, appear to pose a challenge to established thinking. This is because the implied activity is persistently predictable by preceding stimuli, and so cannot arise as this sort of prediction error. Here, we explore three possible accounts of such ramping signals: (a) the resolution of uncertainty about the timing of action; (b) the direct influence of dopamine over mechanisms associated with making choices; and (c) a new model of discounted vigour. Collectively, these suggest that dopamine ramps may be explained, with only minor disturbance, by standard theoretical ideas, though urgent questions remain regarding their proximal cause. We suggest experimental approaches to disentangling which of the proposed mechanisms are responsible for dopamine ramps.

  18. Tamping Ramping: Algorithmic, Implementational, and Computational Explanations of Phasic Dopamine Signals in the Accumbens

    PubMed Central

    Lloyd, Kevin; Dayan, Peter

    2015-01-01

    Substantial evidence suggests that the phasic activity of dopamine neurons represents reinforcement learning’s temporal difference prediction error. However, recent reports of ramp-like increases in dopamine concentration in the striatum when animals are about to act, or are about to reach rewards, appear to pose a challenge to established thinking. This is because the implied activity is persistently predictable by preceding stimuli, and so cannot arise as this sort of prediction error. Here, we explore three possible accounts of such ramping signals: (a) the resolution of uncertainty about the timing of action; (b) the direct influence of dopamine over mechanisms associated with making choices; and (c) a new model of discounted vigour. Collectively, these suggest that dopamine ramps may be explained, with only minor disturbance, by standard theoretical ideas, though urgent questions remain regarding their proximal cause. We suggest experimental approaches to disentangling which of the proposed mechanisms are responsible for dopamine ramps. PMID:26699940

  19. Effect of inactivity and passive stretch on protein turnover in phasic and postural rat muscles

    NASA Technical Reports Server (NTRS)

    Loughna, P.; Goldspink, G.; Goldspink, D. F.

    1986-01-01

    Muscle atrophy in humans can occur during prolonged bed rest, plaster cast immobilization, and space flight. In the present study, the suspension model used by Musacchia et al. (1983) is employed to investigate changes in protein synthesis and degradation in fast-twitch phasic (extensor digitorum longus) and slow-twitch postural (soleus) muscles in the rat, following hypokinesia and hypodynamia. In addition, the use of passive stretch was examined as a means of preventing atrophy. The obtained results suggest that the mechanisms controlling the processes of protein synthesis and protein breakdown during muscle disuse atrophy may be independent of each other. It appears, however, that the muscle atrophy due to hypokinesia and hypodynamia can be temporarily prevented by passively stretching a muscle.

  20. Effects of dietary tryptophan and phenylalanine–tyrosine depletion on phasic alertness in healthy adults – A pilot study

    PubMed Central

    Hildebrand, Patricia; Königschulte, Werner; Gaber, Tilman Jakob; Bubenzer-Busch, Sarah; Helmbold, Katrin; Biskup, Caroline Sarah; Langen, Karl-Josef; Fink, Gereon Rudolf; Zepf, Florian Daniel

    2015-01-01

    Background The synthesis of the neurotransmitters serotonin (5-HT) and dopamine (DA) in the brain can be directly altered by dietary manipulation of their relevant precursor amino acids (AA). There is evidence that altered serotonergic and dopaminergic neurotransmission are both associated with impaired attentional control. Specifically, phasic alertness is one specific aspect of attention that has been linked to changes in 5-HT and DA availability in different neurocircuitries related to attentional processes. The present study investigated the impact of short-term reductions in central nervous system 5-HT and DA synthesis, which was achieved by dietary depletion of the relevant precursor AA, on phasic alertness in healthy adult volunteers; body weight–adapted dietary tryptophan and phenylalanine–tyrosine depletion (PTD) techniques were used. Methods The study employed a double-blind between-subject design. Fifty healthy male and female subjects were allocated to three groups in a randomized and counterbalanced manner and received three different dietary challenge conditions: acute tryptophan depletion (ATD, for the depletion of 5-HT; N=16), PTD (for the depletion of DA; N=17), and a balanced AA load (BAL; N=17), which served as a control condition. Three hours after challenge intake (ATD/PTD/BAL), phasic alertness was assessed using a standardized test battery for attentional performance (TAP). Blood samples for AA level analyses were obtained at baseline and 360 min after the challenge intake. Results Overall, there were no significant differences in phasic alertness for the different challenge conditions. Regarding PTD administration, a positive correlation between the reaction times and the DA-related depletion magnitude was detected via the lower plasma tyrosine levels and the slow reaction times of the first run of the task. In contrast, higher tryptophan concentrations were associated with slower reaction times in the fourth run of the task in the same

  1. Surfactant Proteins SP-A and SP-D Modulate Uterine Contractile Events in ULTR Myometrial Cell Line

    PubMed Central

    Sotiriadis, Georgios; Dodagatta-Marri, Eswari; Kouser, Lubna; Alhamlan, Fatimah S.; Kishore, Uday; Karteris, Emmanouil

    2015-01-01

    Pulmonary surfactant proteins SP-A and SP-D are pattern recognition innate immune molecules. However, there is extrapulmonary existence, especially in the amniotic fluid and at the feto-maternal interface. There is sufficient evidence to suggest that SP-A and SP-D are involved in the initiation of labour. This is of great importance given that preterm birth is associated with increased mortality and morbidity. In this study, we investigated the effects of recombinant forms of SP-A and SP-D (rhSP-A and rhSP-D, the comprising of trimeric lectin domain) on contractile events in vitro, using a human myometrial cell line (ULTR) as an experimental model. Treatment with rhSP-A or rhSP-D increased the cell velocity, distance travelled and displacement by ULTR cells. rhSP-A and rhSP-D also affected the contractile response of ULTRs when grown on collagen matrices showing reduced surface area. We investigated this effect further by measuring contractility-associated protein (CAP) genes. Treatment with rhSP-A and rhSP-D induced expression of oxytocin receptor (OXTR) and connexin 43 (CX43). In addition, rhSP-A and rhSP-D were able to induce secretion of GROα and IL-8. rhSP-D also induced the expression of IL-6 and IL-6 Ra. We provide evidence that SP-A and SP-D play a key role in modulating events prior to labour by reconditioning the human myometrium and in inducing CAP genes and pro-inflammatory cytokines thus shifting the uterus from a quiescent state to a contractile one. PMID:26641881

  2. Assessment of myometrial transcriptome changes associated with spontaneous human labour by high-throughput RNA-seq.

    PubMed

    Chan, Yi-Wah; van den Berg, Hugo A; Moore, Jonathan D; Quenby, Siobhan; Blanks, Andrew M

    2014-03-01

    The transition of the human uterus from a quiescent to a contractile state takes place over a number of weeks. On such biological time scales, cellular phenotype is modified by changes in the transcriptome, which in turn is under the control of the underlying endocrine, paracrine, and biophysical processes resulting from the ongoing pregnancy. In this study, we characterize the transition of the human myometrial transcriptome at term from not in labour (NIL) to in labour (LAB) using high throughput RNA sequencing (RNA-seq). RNA was isolated from the myometrium of uterine biopsies from patients at term who were not in labour (n = 5) and at term in spontaneous labour (n = 5) without augmentation. A total of 143.6 million separate reads were sequenced, achieving, on average, ∼13 times coverage of the expressed human transcriptome per sample. Principal component analysis indicated that the NIL and LAB transcriptomes could be distinguished as two distinct clusters. A comparison of the NIL and LAB groups, using three different statistical approaches (baySeq, edgeR, and DESeq), demonstrated an overlap of 764 differentially expressed genes. A comparison with currently available microarray data revealed only a partial overlap in differentially expressed genes. We conclude that the described RNA-seq data sets represent the first fully annotated catalogue of expressed mRNAs in human myometrium. When considered together, the full expression repertoire and the differentially expressed gene sets should provide an excellent resource for formulating new hypotheses of physiological function, as well as the discovery of novel therapeutic targets.

  3. Cytoplasmic free calcium, myosin light chain phosphorylation, and force in phasic and tonic smooth muscle

    PubMed Central

    1988-01-01

    The time course of [Ca2+]i, tension, and myosin light chain phosphorylation were determined during prolonged depolarization with high K+ in intact tonic (rabbit pulmonary artery) and phasic (longitudinal layer of guinea pig ileum) smooth muscles. [Ca2+]i was monitored with the 340 nm/380 nm signal ratio of the fluorescent indicator fura-2. The fluorescence ratio had a similar time course in both muscle types during depolarization with 109 mM [K+]o; after a transient peak, there was a decline to 70% of its peak value in tonic smooth muscle, and to 60% in phasic smooth muscle. Tension, however, continued to increase in the pulmonary artery, while in the ileum it declined in parallel with the [Ca2+]i. On changing [K+]o from 109 to 20 mM, tension and [Ca2+]i either remained unchanged or declined in parallel in the pulmonary artery. Phosphorylation of the 20-kD myosin light chain, measured during stimulation of muscle strips with 109 mM [K+]o in another set of experiments, increased from 3% to a peak of 50% in the intact pulmonary artery, and then declined to a steady state value of 23%. In the intact ileum, a very rapid, early transient phosphorylation (up to 50%) at 2-3 s was seen. This transient declined by 30 s to a value that was close to the resting level (7%), while tension remained at 55% of its peak force. A quick release during maintained stimulation induced no detectable change in the [Ca2+]i in either type of smooth muscle. We discuss the possibility that the slowly rising tonic tension in pulmonary artery could be due to cooperativity between phosphorylated and nonphosphorylated crossbridges. PMID:3216188

  4. Menthol enhances phasic and tonic GABAA receptor-mediated currents in midbrain periaqueductal grey neurons

    PubMed Central

    Lau, Benjamin K; Karim, Shafinaz; Goodchild, Ann K; Vaughan, Christopher W; Drew, Geoffrey M

    2014-01-01

    Background and Purpose Menthol, a naturally occurring compound in the essential oil of mint leaves, is used for its medicinal, sensory and fragrant properties. Menthol acts via transient receptor potential (TRPM8 and TRPA1) channels and as a positive allosteric modulator of recombinant GABAA receptors. Here, we examined the actions of menthol on GABAA receptor-mediated currents in intact midbrain slices. Experimental Approach Whole-cell voltage-clamp recordings were made from periaqueductal grey (PAG) neurons in midbrain slices from rats to determine the effects of menthol on GABAA receptor-mediated phasic IPSCs and tonic currents. Key Results Menthol (150–750 μM) produced a concentration-dependent prolongation of spontaneous GABAA receptor-mediated IPSCs, but not non-NMDA receptor-mediated EPSCs throughout the PAG. Menthol actions were unaffected by TRPM8 and TRPA1 antagonists, tetrodotoxin and the benzodiazepine antagonist, flumazenil. Menthol also enhanced a tonic current, which was sensitive to the GABAA receptor antagonists, picrotoxin (100 μM), bicuculline (30 μM) and Zn2+ (100 μM), but unaffected by gabazine (10 μM) and a GABAC receptor antagonist, 1,2,5,6-tetrahydropyridin-4-yl)methylphosphinic acid hydrate (TPMPA; 50 μM). In addition, menthol potentiated currents induced by the extrasynaptic GABAA receptor agonist THIP/gaboxadol (10 μM). Conclusions and Implications These results suggest that menthol positively modulates both synaptic and extrasynaptic populations of GABAA receptors in native PAG neurons. The development of agents that potentiate GABAA-mediated tonic currents and phasic IPSCs in a manner similar to menthol could provide a basis for novel GABAA-related pharmacotherapies. PMID:24460753

  5. Decoding brain state transitions in the pedunculopontine nucleus: cooperative phasic and tonic mechanisms.

    PubMed

    Petzold, Anne; Valencia, Miguel; Pál, Balázs; Mena-Segovia, Juan

    2015-01-01

    Cholinergic neurons of the pedunculopontine nucleus (PPN) are most active during the waking state. Their activation is deemed to cause a switch in the global brain activity from sleep to wakefulness, while their sustained discharge may contribute to upholding the waking state and enhancing arousal. Similarly, non-cholinergic PPN neurons are responsive to brain state transitions and their activation may influence some of the same targets of cholinergic neurons, suggesting that they operate in coordination. Yet, it is not clear how the discharge of distinct classes of PPN neurons organize during brain states. Here, we monitored the in vivo network activity of PPN neurons in the anesthetized rat across two distinct levels of cortical dynamics and their transitions. We identified a highly structured configuration in PPN network activity during slow-wave activity that was replaced by decorrelated activity during the activated state (AS). During the transition, neurons were predominantly excited (phasically or tonically), but some were inhibited. Identified cholinergic neurons displayed phasic and short latency responses to sensory stimulation, whereas the majority of non-cholinergic showed tonic responses and remained at high discharge rates beyond the state transition. In vitro recordings demonstrate that cholinergic neurons exhibit fast adaptation that prevents them from discharging at high rates over prolonged time periods. Our data shows that PPN neurons have distinct but complementary roles during brain state transitions, where cholinergic neurons provide a fast and transient response to sensory events that drive state transitions, whereas non-cholinergic neurons maintain an elevated firing rate during global activation.

  6. Decoding brain state transitions in the pedunculopontine nucleus: cooperative phasic and tonic mechanisms

    PubMed Central

    Petzold, Anne; Valencia, Miguel; Pál, Balázs; Mena-Segovia, Juan

    2015-01-01

    Cholinergic neurons of the pedunculopontine nucleus (PPN) are most active during the waking state. Their activation is deemed to cause a switch in the global brain activity from sleep to wakefulness, while their sustained discharge may contribute to upholding the waking state and enhancing arousal. Similarly, non-cholinergic PPN neurons are responsive to brain state transitions and their activation may influence some of the same targets of cholinergic neurons, suggesting that they operate in coordination. Yet, it is not clear how the discharge of distinct classes of PPN neurons organize during brain states. Here, we monitored the in vivo network activity of PPN neurons in the anesthetized rat across two distinct levels of cortical dynamics and their transitions. We identified a highly structured configuration in PPN network activity during slow-wave activity that was replaced by decorrelated activity during the activated state (AS). During the transition, neurons were predominantly excited (phasically or tonically), but some were inhibited. Identified cholinergic neurons displayed phasic and short latency responses to sensory stimulation, whereas the majority of non-cholinergic showed tonic responses and remained at high discharge rates beyond the state transition. In vitro recordings demonstrate that cholinergic neurons exhibit fast adaptation that prevents them from discharging at high rates over prolonged time periods. Our data shows that PPN neurons have distinct but complementary roles during brain state transitions, where cholinergic neurons provide a fast and transient response to sensory events that drive state transitions, whereas non-cholinergic neurons maintain an elevated firing rate during global activation. PMID:26582977

  7. Phasic dopamine release induced by positive feedback predicts individual differences in reversal learning.

    PubMed

    Klanker, Marianne; Sandberg, Tessa; Joosten, Ruud; Willuhn, Ingo; Feenstra, Matthijs; Denys, Damiaan

    2015-11-01

    Striatal dopamine (DA) is central to reward-based learning. Less is known about the contribution of DA to the ability to adapt previously learned behavior in response to changes in the environment, such as a reversal of response-reward contingencies. We hypothesized that DA is involved in the rapid updating of response-reward information essential for successful reversal learning. We trained rats to discriminate between two levers, where lever availability was signaled by a non-discriminative cue. Pressing one lever was always rewarded, whereas the other lever was never rewarded. After reaching stable discrimination performance, a reversal was presented, so that the previously non-rewarded lever was now rewarded and vice versa. We used fast-scan cyclic voltammetry to monitor DA release in the ventromedial striatum. During discrimination performance (pre-reversal), cue presentation induced phasic DA release, whereas reward delivery did not. The opposite pattern was observed post-reversal: Striatal DA release emerged after reward delivery, while cue-induced release diminished. Trial-by-trial analysis showed rapid reinstatement of cue-induced DA release on trials immediately following initial correct responses. This effect of positive feedback was observed in animals that learned the reversal, but not in 'non-learners'. In contrast, neither pre-reversal responding and DA signaling, nor post-reversal DA signaling in response to negative feedback differed between learners and non-learners. Together, we show that phasic DA dynamics in the ventromedial striatum encoding reward-predicting cues are associated with positive feedback during reversal learning. Furthermore, these signals predict individual differences in learning that are not present prior to reversal, suggesting a distinct role for dopamine in the adaptation of previously learned behavior. PMID:26343836

  8. Phasic alertness enhances processing of face and non-face stimuli in congenital prosopagnosia.

    PubMed

    Tanzer, Michal; Weinbach, Noam; Mardo, Elite; Henik, Avishai; Avidan, Galia

    2016-08-01

    Congenital prosopagnosia (CP) is a severe face processing impairment that occurs in the absence of any obvious brain damage and has often been associated with a more general deficit in deriving holistic relations between facial features or even between non-face shape dimensions. Here we further characterized this deficit and examined a potential way to ameliorate it. To this end we manipulated phasic alertness using alerting cues previously shown to modulate attention and enhance global processing of visual stimuli in normal observers. Specifically, we first examined whether individuals with CP, similarly to controls, would show greater global processing when exposed to an alerting cue in the context of a non-facial task (Navon global/local task). We then explored the effect of an alerting cue on face processing (upright/inverted face discrimination). Confirming previous findings, in the absence of alerting cues, controls showed a typical global bias in the Navon task and an inversion effect indexing holistic processing in the upright/inverted task, while CP failed to show these effects. Critically, when alerting cues preceded the experimental trials, both groups showed enhanced global interference and a larger inversion effect. These results suggest that phasic alertness may modulate visual processing and consequently, affect global/holistic perception. Hence, these findings further reinforce the notion that global/holistic processing may serve as a possible mechanism underlying the face processing deficit in CP. Moreover, they imply a possible route for enhancing face processing in individuals with CP and thus shed new light on potential amelioration of this disorder. PMID:27364232

  9. Asymmetry in prefrontal resting-state EEG spectral power underlies individual differences in phasic and sustained cognitive control.

    PubMed

    Ambrosini, Ettore; Vallesi, Antonino

    2016-01-01

    In our daily life, we constantly exert sustained and phasic cognitive control processes to manage multiple competing task sets and rapidly switch between them. Increasing research efforts are attempting to unveil how the brain mediates these processes, highlighting the importance of the prefrontal cortex. An intriguing question concerns the influence of hemispheric asymmetries and whether it may be generalized to different cognitive domains depending on lateralized processing. Another currently open question concerns the underlying causes of the observed huge inter-individual variability in cognitive control abilities. Here we tackle these issues by investigating whether participants' hemispheric asymmetry in intrinsic (i.e., resting-state-related) brain dynamics can reflect differences in their phasic and/or sustained cognitive control abilities regardless of the cognitive domain. To this aim, we recorded human participants' resting-state electroencephalographic activity and performed a source-based spectral analysis to assess their lateralized brain dynamics at rest. Moreover, we used three task-switching paradigms involving different cognitive domains to assess participants' domain-general phasic and sustained cognitive control abilities. By performing a series of correlations and an intersection analysis, we showed that participants with stronger left- and right-lateralized intrinsic brain activity in the middle frontal gyrus were more able, respectively, to exert phasic and sustained cognitive control. We propose that the variability in participants' prefrontal hemispheric asymmetry in the intrinsic electrophysiological spectral profile reflects individual differences in preferentially engaging either the left-lateralized, phasic or the right-lateralized, sustained cognitive control processes to regulate their behavior in response to changing task demands, regardless of the specific cognitive domain involved. PMID:26416650

  10. Phasic excitation of ventral tegmental dopamine neurons potentiates the initiation of conditioned approach behavior: parametric and reinforcement-schedule analyses.

    PubMed

    Ilango, Anton; Kesner, Andrew J; Broker, Carl J; Wang, Dong V; Ikemoto, Satoshi

    2014-01-01

    Midbrain dopamine neurons are implicated in motivation and learning. However, it is unclear how phasic excitation of dopamine neurons, which is implicated in learning, is involved in motivation. Here we used a self-stimulation procedure to examine how mice seek for optogenetically-induced phasic excitation of dopamine neurons, with an emphasis on the temporal dimension. TH-Cre transgenic mice received adeno-associated viral vectors encoding channelrhodopsin-2 into the ventral tegmental area, resulting in selective expression of the opsin in dopamine neurons. These mice were trained to press on a lever for photo-pulse trains that phasically excited dopamine neurons. They learned to self-stimulate in a fast, constant manner, and rapidly reduced pressing during extinction. We first determined effective parameters of photo-pulse trains in self-stimulation. Lever-press rates changed as a function of the manipulation of pulse number, duration, intensity, and frequency. We then examined effects of interval and ratio schedules of reinforcement on photo-pulse train reinforcement, which was contrasted with food reinforcement. Reinforcement with food inhibited lever pressing for a few seconds, after which pressing was robustly regulated in a goal-directed manner. In contrast, phasic excitation of dopamine neurons robustly potentiated the initiation of lever pressing; however, this effect did not last more than 1 s and quickly diminished. Indeed, response rates markedly decreased when lever pressing was reinforced with inter-reinforcement interval schedules of 3 or 10 s or ratio schedules requiring multiple responses per reinforcement. Thus, phasic excitation of dopamine neurons briefly potentiates the initiation of approach behavior with apparent lack of long-term motivational regulation.

  11. Tonic and phasic discharge patterns in toe flexor gamma-motoneurons during locomotion in the decerebrate cat.

    PubMed

    Murphy, P R

    2002-01-01

    To investigate the specificity of fusimotor (gamma) drive during locomotion, gamma-efferents were recorded from the flexor digitorum longus (FDL) and flexor hallucis longus (FHL) nerves in a decerebrate cat preparation. These nerves innervate hindlimb muscles that differ in some aspects of their mechanical action. For both FHL and FDL two stereotyped patterns of gamma activity were distinguished. Tonic units fired throughout the step cycle and had less modulation, but higher minimum rates, than phasic units, which were mainly recruited with ankle extensor [soleus (SOL)] electromyogram (EMG) activity. Differences in the relative timing of these patterns were apparent. In FHL the activity of phasic and most tonic neurons peaked after EMG onset. With FDL, tonic units generally reached maximum rate before, while phasic units peaked after, the beginning of EMG activity. During locomotion FHL and FDL alpha activity were rhythmically recruited with SOL. However, consistent with previous reports, FHL and FDL differed in their patterns of alpha activity. FHL was stereotyped while FDL was variable. Both FHL and FDL had activity related to ankle extensor EMG, but only FDL exhibited a peak around the end of this phase. No corresponding gamma activity was observed in FDL. In conclusion, 1) FHL and FDL received tonic and phasic fusimotor drive; 2) there was no alpha/gamma linkage for the late FDL alpha burst; 3) phasic gamma-efferents in both muscles received similar inputs, linked to plantar flexor alpha activity; and 4) tonic gamma-efferents differed, to the extent that they were modulated at all. The FHL units peaked with the plantar flexor alphas. The FDL neurons generally peaked before alpha activity even began.

  12. Asymmetry in prefrontal resting-state EEG spectral power underlies individual differences in phasic and sustained cognitive control.

    PubMed

    Ambrosini, Ettore; Vallesi, Antonino

    2016-01-01

    In our daily life, we constantly exert sustained and phasic cognitive control processes to manage multiple competing task sets and rapidly switch between them. Increasing research efforts are attempting to unveil how the brain mediates these processes, highlighting the importance of the prefrontal cortex. An intriguing question concerns the influence of hemispheric asymmetries and whether it may be generalized to different cognitive domains depending on lateralized processing. Another currently open question concerns the underlying causes of the observed huge inter-individual variability in cognitive control abilities. Here we tackle these issues by investigating whether participants' hemispheric asymmetry in intrinsic (i.e., resting-state-related) brain dynamics can reflect differences in their phasic and/or sustained cognitive control abilities regardless of the cognitive domain. To this aim, we recorded human participants' resting-state electroencephalographic activity and performed a source-based spectral analysis to assess their lateralized brain dynamics at rest. Moreover, we used three task-switching paradigms involving different cognitive domains to assess participants' domain-general phasic and sustained cognitive control abilities. By performing a series of correlations and an intersection analysis, we showed that participants with stronger left- and right-lateralized intrinsic brain activity in the middle frontal gyrus were more able, respectively, to exert phasic and sustained cognitive control. We propose that the variability in participants' prefrontal hemispheric asymmetry in the intrinsic electrophysiological spectral profile reflects individual differences in preferentially engaging either the left-lateralized, phasic or the right-lateralized, sustained cognitive control processes to regulate their behavior in response to changing task demands, regardless of the specific cognitive domain involved.

  13. Prostaglandin E2 represses interleukin 1 beta-induced inflammatory mediator output from pregnant human myometrial cells through the EP2 and EP4 receptors.

    PubMed

    Mosher, Andrea A; Rainey, Kelly J; Giembycz, Mark A; Wood, Stephen; Slater, Donna M

    2012-07-01

    Inflammatory mediators, including prostaglandins, cytokines, and chemokines, are strongly implicated in the mechanism of human labor, though their precise roles remain unknown. Here we demonstrate that interleukin 1 beta (IL-1beta) significantly increased the expression and release of interleukin-8 (CXCL8), monocyte chemotactic protein-1 (CCL2), and granulocyte macrophage colony-stimulating factor (CSF2) by primary human myometrial cells. However, this effect was repressed by prostaglandin E(2) (PGE(2)). As PGE(2) can activate four distinct PGE(2) receptors (EP(1), EP(2), EP(3), and EP(4)) to elicit various responses, we sought to define the EP receptor(s) responsible for this repression. Using selective EP receptor agonists and a selective EP(4) antagonist, we show that PGE(2) mediates the repression of IL-1beta-induced release of CXCL8, CCL2, and CSF2 via activation of the EP(2) and EP(4) receptors. The use of siRNA gene-specific knockdown further confirmed a role for both receptors. Real-time RT-PCR demonstrated that EP(2) was the most highly expressed of all four EP receptors at the mRNA level in human myometrial cells, and immunocytochemistry showed that EP(2) protein is abundantly present throughout the cells. Interestingly, PGE(2) does not appear to reduce mRNA expression of CXCL8, CCL2, and CSF2. Our results demonstrate that PGE(2) can elicit anti-inflammatory responses via activation of the EP(2) and EP(4) receptors in lower segment term pregnant human myometrial cells. Further elucidation of the EP receptor-mediated signaling pathways in the pregnant human uterus may be beneficial for optimizing the maintenance of pregnancy, induction of labor or indeed treatment of preterm labor.

  14. The respiration of the anterior byssus refractor muscle of Mytilus edulis (ABRM) after a phasic contraction

    PubMed Central

    Baguet, F.; Gillis, J. M.

    1967-01-01

    1. The oxygen consumption of isolated anterior byssus retractor muscle of Mytilus edulis (ABRM) has been measured at rest and after phasic contractions induced by a.c. stimulation. 2. The respiration was measured with a Clark oxygen electrode in successive periods of 5 or 15 min, at 20° C. 3. The resting respiration is 71·8 ± 2·4 n-moles O2/g wet weight.min (mean ± S.E., n = 70). It is increased by a release and decreased by a passive stretch. 4. After phasic stimulation of up to 30 sec the respiration is increased and returns to a slightly higher level than the resting level in an exponential fashion with a time constant of about 10 min. 5. The duration of stimulation does not change the time course of the excess respiration but it affects its magnitude. The amount of extra oxygen consumed, in n-moles O2/g, is made up of a constant amount, 449 ± 102, and an amount that depends on the duration of stimulation (t, sec), which is given by t × 13·2 ± 4·3. When due account is taken for the tension developed, these parameters become 83·1 ± 20·7 and t × 1·24 ± 0·66 n-moles O2/g muscle and kg/cm2 of tension. This regression analysis is based on forty-eight data, with a residual error based on 5 degrees of freedom. 6. Release of the tension after the last stimulus of a 30 sec tetanus reduces by half the extra oxygen consumed during the recovery whereas the same release applied 5 min later has a much smaller effect. This suggests that relaxation is an active process. 7. From these measurements of the recovery metabolism the energy cost of the contraction was estimated and compared with this cost in vertebrate striated muscle. The constant item has about the same magnitude, but the item related to the duration of stimulation is about 250 times smaller. PMID:6032199

  15. The effect of internal sodium and caesium on phasic contraction of patch-clamped rabbit ventricular myocytes.

    PubMed Central

    Levi, A J; Mitcheson, J S; Hancox, J C

    1996-01-01

    1. The voltage dependence of phasic contraction was assessed in rabbit ventricular myocytes. Phasic contraction at all potentials was abolished by exposure to ryanodine-thapsigargin, showing that it was due primarily to Ca2+ release from the sarcoplasmic reticulum (SR). Experiments were performed at 35 degrees C, cells were whole-cell patch clamped and contraction was measured optically as unloaded shortening. Cells were held at -40 mV to inactivate the Na+ current (INa) and T-type Ca2+ current. A standard cellular Ca2+ load was established by applying a train of conditioning pulses at 0.5 Hz before each test pulse. The effect of replacing K+ with Cs+ in the dialysing pipette solution, and the effect of altering dialysing [Na+] between 0 and 20 mM, was assessed on contraction. 2. Cells dialysed with a K(+)-based, Na(+)-free solution exhibited a 'bell-shaped' voltage dependence of the L-type Ca2+ channel current (ICa,L), with a maximum ICa,L at +10 mV. Replacing internal K+ with Cs+, or altering pipette [Na+], did not affect the voltage dependence of ICa,L. 3. The voltage dependence of phasic contraction in cells dialysed with a K(+)-based solution was modulated by pipette [Na+]. The voltage dependence of phasic contraction was bell-shaped with 0 Na+, became much loss bell-shaped with 10 mM Na+ and with 20 mM Na+ the phasic contraction elicited at +100 mV was 1.6-fold larger than that at +10 mV. 4. Replacing 80% of K+ with Cs+ in the pipette dialysis solution led to a significant reduction in contraction amplitude and a more rapid decline in contraction amplitude after beginning the dialysis of the cell. 5. Cells dialysed with a Cs(+)-based solution displayed a voltage dependence of phasic contraction which was more bell-shaped (i.e. more similar to that of ICa,L) than that obtained with the corresponding K(+)-based dialysis solution. The level of pipette [Na+] still modulated the voltage dependence of phasic contraction in cells dialysed with a Cs(+)-based solution

  16. Phasic Burst Stimulation: A Closed-Loop Approach to Tuning Deep Brain Stimulation Parameters for Parkinson’s Disease

    PubMed Central

    Holt, Abbey B.; Wilson, Dan; Moehlis, Jeff; Netoff, Theoden I.

    2016-01-01

    We propose a novel, closed-loop approach to tuning deep brain stimulation (DBS) for Parkinson’s disease (PD). The approach, termed Phasic Burst Stimulation (PhaBS), applies a burst of stimulus pulses over a range of phases predicted to disrupt pathological oscillations seen in PD. Stimulation parameters are optimized based on phase response curves (PRCs), which would be measured from each patient. This approach is tested in a computational model of PD with an emergent population oscillation. We show that the stimulus phase can be optimized using the PRC, and that PhaBS is more effective at suppressing the pathological oscillation than a single phasic stimulus pulse. PhaBS provides a closed-loop approach to DBS that can be optimized for each patient. PMID:27415832

  17. Phasic and Tonic Patterns of Locus Coeruleus Output Differentially Modulate Sensory Network Function in the Awake Rat

    PubMed Central

    Waterhouse, Barry D.

    2011-01-01

    Neurons of the nucleus locus coeruleus (LC) discharge with phasic bursts of activity superimposed on highly regular tonic discharge rates. Phasic bursts are elicited by bottom-up input mechanisms involving novel/salient sensory stimuli and top-down decision making processes; whereas tonic rates largely fluctuate according to arousal levels and behavioral states. Although it is generally believed that these two modes of activity differentially modulate information processing in LC targets, the unique role of phasic versus tonic LC output on signal processing in cells, circuits, and neural networks of waking animals is not well understood. In the current study, simultaneous recordings of individual neurons within ventral posterior medial thalamus and barrel field cortex of conscious rats provided evidence that each mode of LC output produces a unique modulatory impact on single neuron responsiveness to sensory-driven synaptic input and representations of sensory information across ensembles of simultaneously recorded cells. Each mode of LC activation specifically modulated the relationship between sensory-stimulus intensity and the subsequent responses of individual neurons and neural ensembles. Overall these results indicate that phasic versus tonic modes of LC discharge exert fundamentally different modulatory effects on target neuronal circuits within the rodent trigeminal somatosensory system. As such, each mode of LC output may differentially influence signal processing as a means of optimizing behaviorally relevant neural computations within this sensory network. Likely the ability of the LC system to differentially regulate neural responses and local circuit operations according to behavioral demands extends to other brain regions including those involved in higher cognitive functions. PMID:20980542

  18. Pharyngeal pumping in Caenorhabditis elegans depends on tonic and phasic signaling from the nervous system

    PubMed Central

    Trojanowski, Nicholas F.; Raizen, David M.; Fang-Yen, Christopher

    2016-01-01

    Rhythmic movements are ubiquitous in animal locomotion, feeding, and circulatory systems. In some systems, the muscle itself generates rhythmic contractions. In others, rhythms are generated by the nervous system or by interactions between the nervous system and muscles. In the nematode Caenorhabditis elegans, feeding occurs via rhythmic contractions (pumping) of the pharynx, a neuromuscular feeding organ. Here, we use pharmacology, optogenetics, genetics, and electrophysiology to investigate the roles of the nervous system and muscle in generating pharyngeal pumping. Hyperpolarization of the nervous system using a histamine-gated chloride channel abolishes pumping, and optogenetic stimulation of pharyngeal muscle in these animals causes abnormal contractions, demonstrating that normal pumping requires nervous system function. In mutants that pump slowly due to defective nervous system function, tonic muscle stimulation causes rapid pumping, suggesting tonic neurotransmitter release may regulate pumping. However, tonic cholinergic motor neuron stimulation, but not tonic muscle stimulation, triggers pumps that electrophysiologically resemble typical rapid pumps. This suggests that pharyngeal cholinergic motor neurons are normally rhythmically, and not tonically active. These results demonstrate that the pharynx generates a myogenic rhythm in the presence of tonically released acetylcholine, and suggest that the pharyngeal nervous system entrains contraction rate and timing through phasic neurotransmitter release. PMID:26976078

  19. Sucrose-predictive cues evoke greater phasic dopamine release than saccharin-predictive cues

    PubMed Central

    McCutcheon, James E.; Beeler, Jeff A.; Roitman, Mitchell F.

    2012-01-01

    Cues that have been paired with food evoke dopamine in nucleus accumbens (NAc) and drive approach behavior. This cue-evoked dopamine signaling could contribute to overconsumption of food. One manner in which individuals try to restrict caloric intake is through the consumption of foods containing artificial (non-nutritive) sweeteners. We were interested in whether cues paired with a non-nutritive sweetener (saccharin) would evoke similar dopamine release as cues paired with a nutritive sweetener (sucrose). We trained food-restricted rats to associate distinct cues with sucrose or saccharin pellets. In the first group of rats, training sessions with each pellet took place on different days, maximizing the opportunity for rats to detect nutritional differences. After training, voltammetry recordings in NAc core revealed that sucrose cues evoked greater phasic dopamine release than saccharin cues. In a second group of rats, on each training day, sucrose and saccharin pellets were presented in pseudorandom order within the same session, to mask nutritional differences. In this condition, the difference in dopamine between sucrose and saccharin cues was attenuated, but not abolished. These results suggest that sucrose-paired cues will more powerfully motivate behavior than saccharin-paired cues. The differing responses to each cue seem to be driven by overall preference with both the nutritional value that the pellets predict as well as other factors, such as taste, contributing. PMID:22170625

  20. Phasic and tonic alerting in mild cognitive impairment: A preliminary study.

    PubMed

    Martella, Diana; Manzanares, Salvadora; Campoy, Guillermo; Roca, Javier; Antúnez, Carmen; Fuentes, Luis J

    2014-01-01

    In this preliminary study we assessed the functioning of the different attentional networks in mild cognitive impairment (MCI) patients, taking as theoretical framework the Posner's cognitive neuroscience approach. Two groups of participants were tested in a single short experiment: 20 MCI patients (6 amnestic, 6 non-amnestic and 8 multiple-domain) and 18 healthy matched controls (HC). For attentional assessment we used a version of the Attention Network Test (the ANTI-V) that provided not only a score of the orienting, the executive, and the alerting networks and their interactions, but also an independent measure of vigilance (tonic alerting). The results showed that all subtypes of MCI patients exhibited a selective impairment in the tonic component of alerting, as indexed by a decrease in the d' sensitivity index, and their performance in executive network increased up to the HC group level when phasic alerting was provided by a warning tone. Our findings suggest that a core attentional deficit, especially the endogenous component of alerting, may significantly contribute to the behavioral and cognitive deficits associated with MCI.

  1. Sucrose-predictive cues evoke greater phasic dopamine release than saccharin-predictive cues.

    PubMed

    McCutcheon, James E; Beeler, Jeff A; Roitman, Mitchell F

    2012-04-01

    Cues that have been paired with food evoke dopamine in nucleus accumbens (NAc) and drive approach behavior. This cue-evoked dopamine signaling could contribute to overconsumption of food. One manner in which individuals try to restrict caloric intake is through the consumption of foods containing artificial (non-nutritive) sweeteners. We were interested in whether cues paired with a non-nutritive sweetener (saccharin) would evoke similar dopamine release as cues paired with a nutritive sweetener (sucrose). We trained food-restricted rats to associate distinct cues with sucrose or saccharin pellets. In the first group of rats, training sessions with each pellet took place on different days, maximizing the opportunity for rats to detect nutritional differences. After training, voltammetry recordings in NAc core revealed that sucrose cues evoked greater phasic dopamine release than saccharin cues. In a second group of rats, on each training day, sucrose and saccharin pellets were presented in pseudorandom order within the same session, to mask nutritional differences. In this condition, the difference in dopamine between sucrose and saccharin cues was attenuated, but not abolished. These results suggest that sucrose-paired cues will more powerfully motivate behavior than saccharin-paired cues. The differing responses to each cue seem to be driven by overall preference with both the nutritional value that the pellets predict as well as other factors, such as taste, contributing.

  2. Phasic, suprathreshold excitation and sustained inhibition underlie neuronal selectivity for short-duration sounds

    PubMed Central

    Rose, Gary J.; Hanson, Jessica L.; Leary, Christopher J.; Vasquez-Opazo, Gustavo A.; Graham, Jalina A.; Wilkerson, Jeremy

    2016-01-01

    Sound duration is important in acoustic communication, including speech recognition in humans. Although duration-selective auditory neurons have been found, the underlying mechanisms are unclear. To investigate these mechanisms we combined in vivo whole-cell patch recordings from midbrain neurons, extraction of excitatory and inhibitory conductances, and focal pharmacological manipulations. We show that selectivity for short-duration stimuli results from integration of short-latency, sustained inhibition with delayed, phasic excitation; active membrane properties appeared to amplify responses to effective stimuli. Blocking GABAA receptors attenuated stimulus-related inhibition, revealed suprathreshold excitation at all stimulus durations, and decreased short-pass selectivity without changing resting potentials. Blocking AMPA and NMDA receptors to attenuate excitation confirmed that inhibition tracks stimulus duration and revealed no evidence of postinhibitory rebound depolarization inherent to coincidence models of duration selectivity. These results strongly support an anticoincidence mechanism of short-pass selectivity, wherein inhibition and suprathreshold excitation show greatest temporal overlap for long duration stimuli. PMID:26976602

  3. Phasic activation of ventral tegmental neurons increases response and pattern similarity in prefrontal cortex neurons

    PubMed Central

    Iwashita, Motoko

    2014-01-01

    Dopamine is critical for higher neural processes and modifying the activity of the prefrontal cortex (PFC). However, the mechanism of dopamine contribution to the modification of neural representation is unclear. Using in vivo two-photon population Ca2+ imaging in awake mice, this study investigated how neural representation of visual input to PFC neurons is regulated by dopamine. Phasic stimulation of dopaminergic neurons in the ventral tegmental area (VTA) evoked prolonged Ca2+ transients, lasting ∼30 s in layer 2/3 neurons of the PFC, which are regulated by a dopamine D1 receptor-dependent pathway. Furthermore, only a conditioning protocol with visual sensory input applied 0.5 s before the VTA dopaminergic input could evoke enhanced Ca2+ transients and increased pattern similarity (or establish a neural representation) of PFC neurons to the same sensory input. By increasing both the level of neuronal response and pattern similarity, dopaminergic input may establish robust and reliable cortical representation. DOI: http://dx.doi.org/10.7554/eLife.02726.001 PMID:25269147

  4. First calorimetric determination of heat of extraction of 248Cm in a bi-phasic system

    SciTech Connect

    Leigh R. Martin; Peter R. Zalupski

    2011-06-01

    This report presents a summary of the work performed to meet FCR&D level 2 milestone M21SW050201, 'Complete the first calorimetric determination of heat of extraction of 248Cm in a bi-phasic system'. This work was carried out under the auspices of the Thermodynamics and Kinetics FCR&D work package. To complement previous work undertaken under this work package we have extended out heat of extraction studies by di-2-ethyl-hexyl-phosphoric acid to curium. This report also details the heat of extraction of samarium in the same system. This work was performed to not only test the methodology but also to check for consistency with the heats of extraction obtained with those in the prior literature. The heat of extraction for samarium that was obtained in this study was -9.6 kJ mol-1, which is in reasonable agreement with the previously obtained value of -10.9 kJ mol-1. The curium heat of extraction was performed under two sets of conditions and the obtained heats of extraction were in reasonable agreement with each other at -16.0 {+-} 1.1 and -16.8 {+-} 1.5 kJ mol-1.

  5. The psychophysiology of James Bond: phasic emotional responses to violent video game events.

    PubMed

    Ravaja, Niklas; Turpeinen, Marko; Saari, Timo; Puttonen, Sampsa; Keltikangas-Järvinen, Liisa

    2008-02-01

    The authors examined emotional valence- and arousal-related phasic psychophysiological responses to different violent events in the first-person shooter video game "James Bond 007: NightFire" among 36 young adults. Event-related changes in zygomaticus major, corrugator supercilii, and orbicularis oculi electromyographic (EMG) activity and skin conductance level (SCL) were recorded, and the participants rated their emotions and the trait psychoticism based on the Psychoticism dimension of the Eysenck Personality Questionnaire--Revised, Short Form. Wounding and killing the opponent elicited an increase in SCL and a decrease in zygomatic and orbicularis oculi EMG activity. The decrease in zygomatic and orbicularis oculi activity was less pronounced among high Psychoticism scorers compared with low Psychoticism scorers. The wounding and death of the player's own character (James Bond) elicited an increase in SCL and zygomatic and orbicularis oculi EMG activity and a decrease in corrugator activity. Instead of joy resulting from victory and success, wounding and killing the opponent may elicit high-arousal negative affect (anxiety), with high Psychoticism scorers experiencing less anxiety than low Psychoticism scorers. Although counterintuitive, the wounding and death of the player's own character may increase some aspect of positive emotion.

  6. Relation between phasic mitral flow and the echocardiogram of the mitral valve in man.

    PubMed Central

    Vignola, P A; Walker, H J; Pohost, G M; Zir, L M

    1977-01-01

    Ten patients without valvular disease were studied by ventriculography, and the rate and pattern of phasic blood flow into the left ventricle were determined by ventricular volume determinations at intervals of 33 ms during a single diastolic filling period. The derived left ventricular inflow patterns were then compared with the echocardiographic mitral EF slope obtained no more than 25 minutes before left ventriculography. The steepness of the EF slope was found to be inversely correlated with the time required to reach peak inflow velocity (r = 0.80, P less than 0.01) and directly correlated with the peak left ventricular inflow velocity divided by the time required to reach peak velocity (r = 0.72, P less than 0.05). No correlation was found between mean flow velocity into the left ventricle and the EF slope (r = 0.40, P = NS). A significant inverse correlation was found between the EF slope and the fraction of the diastolic filling period elapsed when 50 per cent of the filling volume had entered the left ventricle (r = 0.85, P less than 0.01). These findings suggest that the time required to reach left ventricular peak inflow velocity is one of the determinants of the mitral EF slope. PMID:603729

  7. Phasic respiratory activity in the fetal lamb during late gestation and labour.

    PubMed

    Berger, P J; Walker, A M; Horne, R; Brodecky, V; Wilkinson, M H; Wilson, F; Maloney, J E

    1986-07-01

    We quantified the respiratory activity of 9 fetal lambs using computer-analysis of the diaphragmatic electromyogram (EMG) obtained during 2 h recording sessions interspersed over the last 13 days of gestation. The fetuses delivered unassisted at an average gestational age of 145 days (term = 147 days). During the last 2 h of labour the number of phasic EMG bursts (breaths) averaged 3% of the peak recorded earlier in the study. This decline in breathing began at least 2 days before labour and resulted predominantly from the fetus spending an increasing proportion of time in apnoea. Respiratory rate within epochs of breathing also fell significantly 1 day before labour, and the proportion of time spent in the low voltage electrocortical state declined once labour commenced. No significant change occurred in arterial PO2, PCO2 or pH over the study period. We conclude that fetal respiratory activity falls well before the onset of labour, largely as a result of increased apnoea, and that the decline does not result from the development of a progressive hypoxaemia associated with labour.

  8. Propofol enhances both tonic and phasic inhibitory currents in second-order neurons of the solitary tract nucleus (NTS).

    PubMed

    McDougall, Stuart J; Bailey, Timothy W; Mendelowitz, David; Andresen, Michael C

    2008-03-01

    The anesthetic propofol is thought to induce rapid hypnotic sedation by facilitating a GABAergic tonic current in forebrain neurons. The depression of cardiovascular and respiratory regulation often observed during propofol suggests potential additional actions within the brainstem. Here we determined the impacts of propofol on both GABAergic and glutamatergic synaptic mechanisms in a class of solitary tract nucleus (NTS) neurons common to brainstem reflex pathways. In horizontal brainstem slices, we recorded from NTS neurons directly activated by solitary tract (ST) axons. We identified these second-order NTS neurons by time-invariant ("jitter"<200 micros), "all-or-none" glutamatergic excitatory postsynaptic currents (EPSCs) in response to shocks to the ST. In order to assess propofol actions, we measured ST-evoked, spontaneous and miniature EPSCs and inhibitory postsynaptic currents (IPSCs) during propofol exposure. Propofol prolonged miniature IPSC decay time constants by 50% above control at 1.8 microM. Low concentrations of gabazine (SR-95531) blocked phasic GABA currents. At higher concentrations, propofol (30 microM) induced a gabazine-insensitive tonic current that was blocked by picrotoxin or bicuculline. In contrast, total propofol concentrations up to 30 microM had no effect on EPSCs. Thus, propofol enhanced phasic GABA events in NTS at lower concentrations than tonic current induction, opposite to the relative sensitivity observed in forebrain regions. These data suggest that therapeutic levels of propofol facilitate phasic (synaptic) inhibitory transmission in second-order NTS neurons which likely inhibits autonomic reflex pathways during anesthesia.

  9. A nonlinear macroscopic multi-phasic model for describing interactions between solid, fluid and ionic species in biological tissue materials

    NASA Astrophysics Data System (ADS)

    Li, Long-yuan; Pinsky, Peter M.

    2011-01-01

    A nonlinear, macroscopic multi-phasic model for describing the interactions between solid, fluid, and ionic species in porous materials is presented. Governing equations are derived based on the nonlinear theories of solid mechanics, linear flow theory of Newtonian fluids, and theory of irreversible thermodynamics for the transport of ions and ionic solutions. The model shows that the transport coupling between ions and ionic solution exists only when the porous material has a membrane-like feature, which could be inside the material or on the material boundaries. Otherwise, the coupling occurs only between the solid and fluid phases and the transport of ionic species will have no effect on the macroscopic stresses, strains and displacements of the porous material. As an application of the present multi-phasic model, a numerical example of the human cornea under the shock of NaCl hypertonic solution applied to its endothelial surface is presented. This is a typical example of how ionic transport induces swelling in biological tissues. The results obtained from the present multi-phasic model demonstrate that the mechanical properties of the tissue have an important influence on the swelling of the cornea. Without taking into account this influence, the predicted swelling may be exaggerated.

  10. Intracellular pH modulates taste receptor cell volume and the phasic part of the chorda tympani response to acids.

    PubMed

    Lyall, Vijay; Pasley, Hampton; Phan, Tam-Hao T; Mummalaneni, Shobha; Heck, Gerard L; Vinnikova, Anna K; DeSimone, John A

    2006-01-01

    The relationship between cell volume and the neural response to acidic stimuli was investigated by simultaneous measurements of intracellular pH (pHi) and cell volume in polarized fungiform taste receptor cells (TRCs) using 2',7'-bis-(2-carboxyethyl)-5-(and-6)-carboxyfluorescein (BCECF) in vitro and by rat chorda tympani (CT) nerve recordings in vivo. CT responses to HCl and CO2 were recorded in the presence of 1 M mannitol and specific probes for filamentous (F) actin (phalloidin) and monomeric (G) actin (cytochalasin B) under lingual voltage clamp. Acidic stimuli reversibly decrease TRC pHi and cell volume. In isolated TRCs F-actin and G-actin were labeled with rhodamine phalloidin and bovine pancreatic deoxyribonuclease-1 conjugated with Alexa Fluor 488, respectively. A decrease in pHi shifted the equilibrium from F-actin to G-actin. Treatment with phalloidin or cytochalasin B attenuated the magnitude of the pHi-induced decrease in TRC volume. The phasic part of the CT response to HCl or CO2 was significantly decreased by preshrinking TRCs with hypertonic mannitol and lingual application of 1.2 mM phalloidin or 20 microM cytochalasin B with no effect on the tonic part of the CT response. In TRCs first treated with cytochalasin B, the decrease in the magnitude of the phasic response to acidic stimuli was reversed by phalloidin treatment. The pHi-induced decrease in TRC volume induced a flufenamic acid-sensitive nonselective basolateral cation conductance. Channel activity was enhanced at positive lingual clamp voltages. Lingual application of flufenamic acid decreased the magnitude of the phasic part of the CT response to HCl and CO2. Flufenamic acid and hypertonic mannitol were additive in inhibiting the phasic response. We conclude that a decrease in pHi induces TRC shrinkage through its effect on the actin cytoskeleton and activates a flufenamic acid-sensitive basolateral cation conductance that is involved in eliciting the phasic part of the CT response to

  11. Characteristic phasic evolution of convulsive seizure in PCDH19-related epilepsy.

    PubMed

    Ikeda, Hiroko; Imai, Katsumi; Ikeda, Hitoshi; Shigematsu, Hideo; Takahashi, Yukitoshi; Inoue, Yushi; Higurashi, Norimichi; Hirose, Shinichi

    2016-03-01

    PCDH19-related epilepsy is a genetic disorder that was first described in 1971, then referred to as "epilepsy and mental retardation limited to females". PCDH19 has recently been identified as the responsible gene, but a detailed characterization of the seizure manifestation based on video-EEG recording is still limited. The purpose of this study was to elucidate features of the seizure semiology in children with PCDH19-related epilepsy. To do this, ictal video-EEG recordings of 26 convulsive seizures in three girls with PCDH19-related epilepsy were analysed. All seizures occurred in clusters, mainly during sleep accompanied by fever. The motor manifestations consisted of six sequential phases: "jerk", "reactive", "mild tonic", "fluttering", "mild clonic", and "postictal". Some phases were brief or lacking in some seizures, whereas others were long or pronounced. In the reactive phase, the patients looked fearful or startled with sudden jerks and turned over reactively. The tonic and clonic components were less intense compared with those of typical tonic-clonic seizures in other types of epilepsy. The fluttering phase was characterised initially by asymmetric, less rhythmic, and less synchronous tremulous movement and was then followed by the subtle clonic phase. Subtle oral automatism was observed in the postictal phase. The reactive, mild tonic, fluttering and mild clonic phases were most characteristic of seizures of PCDH19-related epilepsy. Ictal EEG started bilaterally and was symmetric in some patients but asymmetric in others. It showed asymmetric rhythmic discharges in some seizures at later phases. The electroclinical pattern of the phasic evolution of convulsive seizure suggests a focal onset seizure with secondary generalisation. Based on our findings, we propose that the six unique sequential phases in convulsive seizures suggest the diagnosis of PCDH19-related epilepsy when occurring in clusters with or without high fever in girls. [Published with

  12. Serotonergic agonists stimulate inositol lipid metabolism in rabbit platelets

    SciTech Connect

    Schaechter, M.; Godfrey, P.P.; Minchin, M.C.W.; McClue, S.J.; Young, M.M.

    1985-10-28

    The metabolism of inositol phospholipids in response to serotonergic agonists was investigated in rabbit platelets. In platelets prelabelled with (/sup 3/H)-inositol, in a medium containing 10 mM LiCl which blocks the enzyme inositol-1-phosphatase, 5-hydroxytryptamine (5-HT) caused a dose-dependent accumulation of inositol phosphates (IP). This suggests a phospholipase-C-mediated breakdown of phosphoinositides. Ketanserin, a selective 5-HT/sub 2/ antagonist, was a potent inhibitor of the 5-HT response, with a Ki of 28 nM, indicating that 5-HT is activating receptors of the 5-HT/sub 2/ type in the platelet. Lysergic acid diethylamide (LSD) and quipazine also caused dose-related increases in inositol phosphate levels, though these were considerably less than those produced by 5-HT. These results show that relatively small changes in phosphoinositide metabolism induced by serotonergic agonists can be investigated in the rabbit platelet, and this cell may therefore be a useful model for the study of some 5-HT receptors. 30 references, 4 figures.

  13. Differences in colonic tone and phasic response to a meal in the transverse and sigmoid human colon.

    PubMed Central

    Ford, M J; Camilleri, M; Wiste, J A; Hanson, R B

    1995-01-01

    It is not yet clear whether the regional differences in the physical properties of the colon influence its motor responses. Tonic and phasic colonic motility and compliance of the transverse and sigmoid colon were therefore assessed using a combined barostat-manometry assembly in 22 healthy subjects. Measured colonic compliance was corrected by subtraction of the compliance of the closed barostat system. The mean (SEM) preprandial colonic volumes in the transverse and sigmoid colon were similar (150 (12) and 128 (13) ml, p = NS), corresponding to calculated mean (SEM) colonic diameters of 4.3 cm and 4.0 cm respectively. The mean increase in colonic tone postprandially was significantly greater in the transverse (24.1% (3.5)) than in the sigmoid colon (13.1% (3.0), p < 0.01). The mean increase in phasic contractility was significantly greater, however, in the sigmoid than in the transverse colon (1270 (210) and 425 (60) mm Hg/90 min respectively, p < 0.01). Compliance was greater in the transverse than sigmoid colon (7.6 (0.44) and 4.1 (0.15) ml/mm Hg, p < 0.001). The fasting volume of the colon was significantly correlated with the magnitude of the tonic response to the meal in the transverse and sigmoid colon (p < 0.001 for both). In conclusion, there are quantitatively different but qualitatively similar phasic and tonic responses to the meal in the two colonic regions. Differences in the viscoelastic and luminal dimensions may partly account for these differences in tonic responses. PMID:7557579

  14. Impaired Pavlovian predictive learning between temporally phasic but not static events in autism-model strain mice.

    PubMed

    Kosaki, Yutaka; Watanabe, Shigeru

    2016-10-01

    Autism-spectrum disorder (ASD) is a multi-aspect developmental disorder characterised by various social and non-social behavioural abnormalities. Using BTBR T+ tf mouse strain (BTBR), a promising animal model displaying a number of behavioural and neural characteristics associated with ASD, we tested the hypothesis that at the core of various symptoms of ASD lies a fundamental deficit in predictive learning between events. In five experiments, we conducted a variety of Pavlovian conditioning tasks, some requiring the establishment of associations between temporally phasic events and others involving static events. BTBR mice were impaired in the acquisition of conditioned magazine approach responses with an appetitive unconditioned stimulus (US) (Experiment 1) and conditioned freezing with an electric shock US (Experiment 2). Both of these tasks had temporally phasic conditioned stimuli (CSs). Conversely, these mice showed normal acquisition of conditioned place preference (CPP), whether the US was a systemic injection of methamphetamine (Experiment 3A) or the presence of food (Experiment 3B). Experiment 4 showed normal acquisition of conditioned taste aversion (CTA) to a flavour-taste compound CS, although BTBR mice still exhibited an abnormal stimulus selection when learning for each element of the compound CS was assessed separately. Experiment 5 revealed a weaker latent inhibition of CTA in BTBR mice. The BTBR mouse's impaired predictive learning between phasic events and intact associations between static events are discussed in terms of dysfunctional contingency-based, but not contiguity-based learning, which may accompany abnormal selective attention to relevant cues. We propose that such dysfunctional contingency learning mechanisms may underlie the development of various social and non-social symptoms of ASD.

  15. Impaired Pavlovian predictive learning between temporally phasic but not static events in autism-model strain mice.

    PubMed

    Kosaki, Yutaka; Watanabe, Shigeru

    2016-10-01

    Autism-spectrum disorder (ASD) is a multi-aspect developmental disorder characterised by various social and non-social behavioural abnormalities. Using BTBR T+ tf mouse strain (BTBR), a promising animal model displaying a number of behavioural and neural characteristics associated with ASD, we tested the hypothesis that at the core of various symptoms of ASD lies a fundamental deficit in predictive learning between events. In five experiments, we conducted a variety of Pavlovian conditioning tasks, some requiring the establishment of associations between temporally phasic events and others involving static events. BTBR mice were impaired in the acquisition of conditioned magazine approach responses with an appetitive unconditioned stimulus (US) (Experiment 1) and conditioned freezing with an electric shock US (Experiment 2). Both of these tasks had temporally phasic conditioned stimuli (CSs). Conversely, these mice showed normal acquisition of conditioned place preference (CPP), whether the US was a systemic injection of methamphetamine (Experiment 3A) or the presence of food (Experiment 3B). Experiment 4 showed normal acquisition of conditioned taste aversion (CTA) to a flavour-taste compound CS, although BTBR mice still exhibited an abnormal stimulus selection when learning for each element of the compound CS was assessed separately. Experiment 5 revealed a weaker latent inhibition of CTA in BTBR mice. The BTBR mouse's impaired predictive learning between phasic events and intact associations between static events are discussed in terms of dysfunctional contingency-based, but not contiguity-based learning, which may accompany abnormal selective attention to relevant cues. We propose that such dysfunctional contingency learning mechanisms may underlie the development of various social and non-social symptoms of ASD. PMID:27521755

  16. Early detection of acute transmural myocardial ischemia by the phasic systolic-diastolic changes of local tissue electrical impedance.

    PubMed

    Jorge, Esther; Amorós-Figueras, Gerard; García-Sánchez, Tomás; Bragós, Ramón; Rosell-Ferrer, Javier; Cinca, Juan

    2016-02-01

    Myocardial electrical impedance is influenced by the mechanical activity of the heart. Therefore, the ischemia-induced mechanical dysfunction may cause specific changes in the systolic-diastolic pattern of myocardial impedance, but this is not known. This study aimed to analyze the phasic changes of myocardial resistivity in normal and ischemic conditions. Myocardial resistivity was measured continuously during the cardiac cycle using 26 different simultaneous excitation frequencies (1 kHz-1 MHz) in 7 anesthetized open-chest pigs. Animals were submitted to 30 min regional ischemia by acute left anterior descending coronary artery occlusion. The electrocardiogram, left ventricular (LV) pressure, LV dP/dt, and aortic blood flow were recorded simultaneously. Baseline myocardial resistivity depicted a phasic pattern during the cardiac cycle with higher values at the preejection period (4.19 ± 1.09% increase above the mean, P < 0.001) and lower values during relaxation phase (5.01 ± 0.85% below the mean, P < 0.001). Acute coronary occlusion induced two effects on the phasic resistivity curve: 1) a prompt (5 min ischemia) holosystolic resistivity rise leading to a bell-shaped waveform and to a reduction of the area under the LV pressure-impedance curve (1,427 ± 335 vs. 757 ± 266 Ω·cm·mmHg, P < 0.01, 41 kHz) and 2) a subsequent (5-10 min ischemia) progressive mean resistivity rise (325 ± 23 vs. 438 ± 37 Ω·cm at 30 min, P < 0.01, 1 kHz). The structural and mechanical myocardial dysfunction induced by acute coronary occlusion can be recognized by specific changes in the systolic-diastolic myocardial resistivity curve. Therefore these changes may become a new indicator (surrogate) of evolving acute myocardial ischemia.

  17. Swimming away or clamming up: the use of phasic and tonic adductor muscles during escape responses varies with shell morphology in scallops.

    PubMed

    Tremblay, Isabelle; Guderley, Helga E; Himmelman, John H

    2012-12-01

    The simple locomotor system of scallops facilitates the study of muscle use during locomotion. We compared five species of scallops with different shell morphologies to see whether shell morphology and muscle use change in parallel or whether muscle use can compensate for morphological constraints. Force recordings during escape responses revealed that the use of tonic and phasic contractions varied markedly among species. The active species, Amusium balloti, Placopecten magellanicus and Pecten fumatus, made more phasic contractions than the more sedentary species, Mimachlamys asperrima and Crassadoma gigantea. Tonic contractions varied considerably among these species, with the two more sedentary species often starting their response to the predator with a tonic contraction and the more active species using shorter tonic contractions between series of phasic contractions. Placopecten magellanicus made extensive use of short tonic contractions. Pecten fumatus mounted an intense series of phasic contractions at the start of its response, perhaps to overcome the constraints of its unfavourable shell morphology. Valve closure by the more sedentary species suggests that their shell morphology protects them against predation, whereas swimming by the more active species relies upon intense phasic contractions together with favourable shell characteristics. PMID:22972884

  18. The cooperation of sustained and phasic inhibitions increases the contrast of ITD-tuning in low-frequency neurons of the chick nucleus laminaris.

    PubMed

    Yamada, Rei; Okuda, Hiroko; Kuba, Hiroshi; Nishino, Eri; Ishii, Takahiro M; Ohmori, Harunori

    2013-02-27

    Neurons in the nucleus laminaris (NL) of birds detect the coincidence of binaural excitatory inputs from the nucleus magnocellularis (NM) on both sides and process the interaural time differences (ITDs) for sound localization. Sustained inhibition from the superior olivary nucleus is known to control the gain of coincidence detection, which allows the sensitivity of NL neurons to ITD tolerate strong-intensity sound. Here, we found a phasic inhibition in chicken brain slices that follows the ipsilateral NM inputs after a short time delay, sharpens coincidence detection, and may enhance ITD sensitivity in low-frequency NL neurons. GABA-positive small neurons are distributed in and near the NL. These neurons generate IPSCs in NL neurons when photoactivated by a caged glutamate compound, suggesting that these GABAergic neurons are interneurons that mediate phasic inhibition. These IPSCs have fast decay kinetics that is attributable to the α1-subunit of the GABAA receptor, the expression of which dominates in the low-frequency region of the NL. Model simulations demonstrate that phasic IPSCs narrow the time window of coincidence detection and increase the contrast of ITD-tuning during low-level, low-frequency excitatory input. Furthermore, cooperation of the phasic and sustained inhibitions effectively increases the contrast of ITD-tuning over a wide range of excitatory input levels. We propose that the complementary interaction between phasic and sustained inhibitions is the neural mechanism that regulates ITD sensitivity for low-frequency sound in the NL. PMID:23447603

  19. Modeling phasic insulin release: immediate and time-dependent effects of glucose.

    PubMed

    Nesher, Rafael; Cerasi, Erol

    2002-02-01

    The cellular and molecular mechanisms of insulin secretion are being intensively investigated, yet most researchers are seemingly unaware of the complexity of the dynamic regulation of the secretion. In this article, we summarize studies of the physiology of insulin secretion performed over several decades. The insulin response of perifused islets of rats, perfused rat pancreas, or that of a human, to a square-wave glucose stimulus is biphasic, a transient first-phase response of 4- to 10-min duration followed by a gradual rise in secretion rates (second-phase response). Several hypotheses have been proposed to account for the phasic nature of insulin secretion; they are briefly discussed in this review. We have favored the hypothesis that nutrient stimulators such as glucose, in addition to a primary and almost immediate secretory signal, with time induce both stimulatory and inhibitory messages in the beta-cell, and those messages modulate the primary insulinogenic signal. Indeed, studies in the rat pancreas and in humans have demonstrated that short stimulations with glucose generate a state of refractoriness of the insulin secretion, which we have termed time-dependent inhibition (TDI). Nonnutrient secretagogues such as arginine induce strong TDI independent of the duration of stimulation. Once the agent is removed, TDI persists for a considerable period. In contrast, prolonged stimulations with glucose (and other nutrients) lead to the amplification of the insulin response to subsequent stimuli; this can be demonstrated in the perfused rat pancreas, in perifused islets from several rodents, and in humans. We have termed this stimulatory signal time-dependent potentiation (TDP). The generation of TDP requires higher glucose concentrations and prolonged stimulation; the effect is retained for some time after cessation of the stimulus. Of major interest is the observation that, while the acute insulin response to glucose is severely reduced in glucose

  20. [VOLEMIC STATUS AND THE PHASIC APPROACH TO THE TREATMENT OF CRITICAL STATES--NEW OPPORTUNITES AND PROSPECTS].

    PubMed

    Kuz'kov, V V; Fot, E V; Smjotkin, A A; Lebedinskij, K M; Kirov, M Yu

    2015-01-01

    Current guidelines suggest that an early and aggressive fluid therapy is the best rescue approach to restore and preserve cardiac index, organ function and decrease the risk of multiple organ failure in shock of various origin. However, escala- tion of fluid resuscitation is a double-edged sword often associated with reperfusion, glicocalyx injury, capillary leakage, delayed weight gain and heperhydration. The body of evidences demons trates that an excessive fluid load in ICUpatient with global increased permeability syndrome, and, particularly, in ARDS and acute kidney injury can be devastating, particularly when guided with central venous pressure. This important therapeutical conflict highlights the importance of the emerging concept of "phasic "fluid management and physiologic monitoring. The type and volume of the fluid should be thoroughly selected in accordance with the phase of shock, risk of impending organ dysfunction and individual co-morbidity. The phasic approach, along with individualized early and delayed goal-directed protocols might fasten the resolution of organ dysfunction, reduce the duration of shock and mechanical ventilation and improve the outcomes. PMID:27025140

  1. AIC649 Induces a Bi-Phasic Treatment Response in the Woodchuck Model of Chronic Hepatitis B.

    PubMed

    Paulsen, Daniela; Weber, Olaf; Ruebsamen-Schaeff, Helga; Tennant, Bud C; Menne, Stephan

    2015-01-01

    AIC649 has been shown to directly address the antigen presenting cell arm of the host immune defense leading to a regulated cytokine release and activation of T cell responses. In the present study we analyzed the antiviral efficacy of AIC649 as well as its potential to induce functional cure in animal models for chronic hepatitis B. Hepatitis B virus transgenic mice and chronically woodchuck hepatitis virus (WHV) infected woodchucks were treated with AIC649, respectively. In the mouse system AIC649 decreased the hepatitis B virus titer as effective as the "gold standard", Tenofovir. Interestingly, AIC649-treated chronically WHV infected woodchucks displayed a bi-phasic pattern of response: The marker for functional cure--hepatitis surface antigen--first increased but subsequently decreased even after cessation of treatment to significantly reduced levels. We hypothesize that the observed bi-phasic response pattern to AIC649 treatment reflects a physiologically "concerted", reconstituted immune response against WHV and therefore may indicate a potential for inducing functional cure in HBV-infected patients. PMID:26656974

  2. Trophic Ecology of Benthic Marine Invertebrates with Bi-Phasic Life Cycles: What Are We Still Missing?

    PubMed

    Calado, Ricardo; Leal, Miguel Costa

    2015-01-01

    The study of trophic ecology of benthic marine invertebrates with bi-phasic life cycles is critical to understand the mechanisms shaping population dynamics. Moreover, global climate change is impacting the marine environment at an unprecedented level, which promotes trophic mismatches that affect the phenology of these species and, ultimately, act as drivers of ecological and evolutionary change. Assessing the trophic ecology of marine invertebrates is critical to understanding maternal investment, larval survival to metamorphosis, post-metamorphic performance, resource partitioning and trophic cascades. Tools already available to assess the trophic ecology of marine invertebrates, including visual observation, gut content analysis, food concentration, trophic markers, stable isotopes and molecular genetics, are reviewed and their main advantages and disadvantages for qualitative and quantitative approaches are discussed. The challenges to perform the partitioning of ingestion, digestion and assimilation are discussed together with different approaches to address each of these processes for short- and long-term fingerprinting. Future directions for research on the trophic ecology of benthic marine invertebrates with bi-phasic life cycles are discussed with emphasis on five guidelines that will allow for systematic study and comparative meta-analysis to address important unresolved questions.

  3. Context-dependent modulation of alphabetagamma and alphabetadelta GABA A receptors by penicillin: implications for phasic and tonic inhibition.

    PubMed

    Feng, Hua-Jun; Botzolakis, Emmanuel J; Macdonald, Robert L

    2009-01-01

    Penicillin, an open-channel blocker of GABA(A) receptors, was recently reported to inhibit phasic, but not tonic, currents in hippocampal neurons. To distinguish between isoform-specific and context-dependent modulation as possible explanations for this selectivity, the effects of penicillin were evaluated on recombinant GABA(A) receptors expressed in HEK293T cells. When co-applied with saturating GABA, penicillin decreased peak amplitude, induced rebound, and prolonged deactivation of currents evoked from both synaptic and extrasynaptic receptor isoforms. However, penicillin had isoform-specific effects on the extent of desensitization, reflecting its ability to differentially modulate peak (non-equilibrium) and residual (near-equilibrium) currents. This suggested that the context of activation could determine the apparent sensitivity of a given receptor isoform to penicillin. To test this hypothesis, we explored the ability of penicillin to modulate synaptic and extrasynaptic isoform currents that were activated under more physiologically relevant conditions. Interestingly, while currents evoked from synaptic isoforms under phasic conditions (transient activation by a saturating concentration of GABA) were substantially inhibited by penicillin, currents evoked from extrasynaptic isoforms under tonic conditions (prolonged application by a sub-saturating concentration of GABA) were minimally affected. We therefore concluded that the reported inability of penicillin to modulate tonic currents could not simply be attributed to insensitivity of extrasynaptic receptors, but rather, reflected an inability to modulate these receptors in their native context of activation.

  4. Adolescent Alcohol Exposure Amplifies the Incentive Value of Reward-Predictive Cues Through Potentiation of Phasic Dopamine Signaling.

    PubMed

    Spoelder, Marcia; Tsutsui, Kimberly T; Lesscher, Heidi M B; Vanderschuren, Louk J M J; Clark, Jeremy J

    2015-12-01

    Adolescent alcohol use remains a major public health concern due in part to well-established findings implicating the age of onset in alcohol use in the development of alcohol use disorders and persistent decision-making deficits in adults. We have previously demonstrated that moderate adolescent alcohol consumption in rats promotes suboptimal decision making and an associated perturbation in mesolimbic dopamine transmission in adulthood. Dopamine-dependent incentive learning processes are an integral component of value-based decision making and a fundamental element to many theoretical accounts of addiction. Thus we tested the hypothesis that adolescent alcohol use selectively alters incentive learning processes through perturbation of mesolimbic dopamine systems. To assess incentive learning, behavioral and neurochemical measurements were made during the acquisition, maintenance, extinction, and reacquisition of a Pavlovian conditioned approach procedure in adult rats with a history of adolescent alcohol consumption. We show that moderate adolescent alcohol consumption potentiates stimulus-evoked phasic dopamine transmission, measured in vivo by fast-scan cyclic voltammetry, in adulthood and biases individuals toward a dopamine-dependent incentive learning strategy. Moreover, we demonstrate that animals exposed to alcohol in adolescence are more sensitive to an unexpected variation in reward outcomes. This pattern of phasic dopamine signaling and the associated bias in learning may provide a mechanism for the well-documented vulnerability of individuals with early-life alcohol use for alcohol use disorders in adulthood.

  5. Adolescent Alcohol Exposure Amplifies the Incentive Value of Reward-Predictive Cues Through Potentiation of Phasic Dopamine Signaling.

    PubMed

    Spoelder, Marcia; Tsutsui, Kimberly T; Lesscher, Heidi M B; Vanderschuren, Louk J M J; Clark, Jeremy J

    2015-12-01

    Adolescent alcohol use remains a major public health concern due in part to well-established findings implicating the age of onset in alcohol use in the development of alcohol use disorders and persistent decision-making deficits in adults. We have previously demonstrated that moderate adolescent alcohol consumption in rats promotes suboptimal decision making and an associated perturbation in mesolimbic dopamine transmission in adulthood. Dopamine-dependent incentive learning processes are an integral component of value-based decision making and a fundamental element to many theoretical accounts of addiction. Thus we tested the hypothesis that adolescent alcohol use selectively alters incentive learning processes through perturbation of mesolimbic dopamine systems. To assess incentive learning, behavioral and neurochemical measurements were made during the acquisition, maintenance, extinction, and reacquisition of a Pavlovian conditioned approach procedure in adult rats with a history of adolescent alcohol consumption. We show that moderate adolescent alcohol consumption potentiates stimulus-evoked phasic dopamine transmission, measured in vivo by fast-scan cyclic voltammetry, in adulthood and biases individuals toward a dopamine-dependent incentive learning strategy. Moreover, we demonstrate that animals exposed to alcohol in adolescence are more sensitive to an unexpected variation in reward outcomes. This pattern of phasic dopamine signaling and the associated bias in learning may provide a mechanism for the well-documented vulnerability of individuals with early-life alcohol use for alcohol use disorders in adulthood. PMID:25971592

  6. Neurosteroid interactions with synaptic and extrasynaptic GABAa receptors: regulation of subunit plasticity, phasic and tonic inhibition, and neuronal network excitability

    PubMed Central

    Chase Matthew, Carver; Doodipala Samba, Reddy

    2013-01-01

    Rationale Neurosteroids are steroids synthesized within the brain with rapid effects on neuronal excitability. Allopregnanolone, allotetrahydrodeoxycorticosterone, and androstanediol are three widely explored prototype endogenous neurosteroids. They have very different targets and functions compared to conventional steroid hormones. Neuronal GABAa receptors are one of the prime molecular targets of neurosteroids. Objective This review provides a critical appraisal of recent advances in the pharmacology of endogenous neurosteroids that interact with GABAa receptors in the brain. Neurosteroids possess distinct, characteristic effects on the membrane potential and current conductance of the neuron, mainly via potentiation of GABAa receptors at low concentrations and direct activation of receptor chloride channel at higher concentrations. The GABAa receptor mediates two types of inhibition, now characterized as synaptic (phasic) and extrasynaptic (tonic) inhibition. Synaptic release of GABA results in the activation of low-affinity γ2-containing synaptic receptors, while high-affinity δ-containing extrasynaptic receptors are persistently activated by the ambient GABA present in the extracellular fluid. Neurosteroids are potent positive allosteric modulators of synaptic and extrasynaptic GABAa receptors and therefore enhance both phasic and tonic inhibition. Tonic inhibition is specifically more sensitive to neurosteroids. The resulting tonic conductance generates a form of shunting inhibition that controls neuronal network excitability, seizure susceptibility, and behavior. Conclusion The growing understanding of the mechanisms of neurosteroid regulation of the structure and function of the synaptic and extrasynaptic GABAa receptors provide many opportunities to create improved therapies for sleep, anxiety, stress, epilepsy, and other neuropsychiatric conditions. PMID:24071826

  7. Antinociceptive potency of aminoglycoside antibiotics and magnesium chloride: a comparative study on models of phasic and incisional pain in rats.

    PubMed

    Prado, W A; Machado Filho, E B

    2002-03-01

    A close relationship exists between calcium concentration in the central nervous system and nociceptive processing. Aminoglycoside antibiotics and magnesium interact with N- and P/Q-type voltage-operated calcium channels. In the present study we compare the antinociceptive potency of intrathecal administration of aminoglycoside antibiotics and magnesium chloride in the tail-flick test and on incisional pain in rats, taken as models of phasic and persistent post-surgical pain, respectively. The order of potency in the tail-flick test was gentamicin (ED50 = 3.34 microg; confidence limits 2.65 and 4.2) > streptomycin (5.68 microg; 3.76 and 8.57) = neomycin (9.22 microg; 6.98 and 12.17) > magnesium (19.49 microg; 11.46 and 33.13). The order of potency to reduce incisional pain was gentamicin (ED50 = 2.06 microg; confidence limits 1.46 and 2.9) > streptomycin (47.86 microg; 26.3 and 87.1) = neomycin (83.17 microg; 51.6 and 133.9). The dose-response curves for each test did not deviate significantly from parallelism. We conclude that neomycin and streptomycin are more potent against phasic pain than against persistent pain, whereas gentamicin is equipotent against both types of pain. Magnesium was less potent than the antibiotics and effective in the tail-flick test only.

  8. The association of the microcystic, elongated and fragmented (MELF) invasion pattern in endometrial carcinomas with deep myometrial invasion, lymphovascular space invasion and lymph node metastasis.

    PubMed

    Dogan Altunpulluk, M; Kir, G; Topal, C S; Cetiner, H; Gocmen, A

    2015-05-01

    The purpose of this study was to investigate the frequency of microcystic, elongated and fragmented (MELF) pattern of invasion in endometrioid endometrial adenocarcinomas (EA) and its association with prognostic factors. Stained tissue sections from 121 cases of EA (total hysterectomy and pelvic, with or without para-aortic, lymphadenectomy specimens) were reviewed to identify cases showing MELF-type invasion. The prognostic factors of low tumour grade, deep myometrial invasion (MI), cervical stromal involvement, lymphovascular space invasion (LVSI), lymph node (LN) metastasis and advanced clinical stage were more frequently observed in MELF-positive cases (p < 0.05). Thus, MELF-positive cases had an increased frequency (28/121) of these prognostic factors, which has implications in routine clinical practice, as it signals the importance of recognising MELF pattern invasion. In univariate analysis, MELF positivity, deep MI, cervical stroma involvement and LVSI were significantly related to LN metastasis (p < 0.05). However, in multivariate analysis, only MELF pattern invasion and cervical stroma involvement were independent factors for LN metastasis. Nevertheless, further studies are needed to evaluate the clinical significance of MELF pattern of invasion in endometrial adenocarcinoma.

  9. Phasic dopamine as a prediction error of intrinsic and extrinsic reinforcements driving both action acquisition and reward maximization: a simulated robotic study.

    PubMed

    Mirolli, Marco; Santucci, Vieri G; Baldassarre, Gianluca

    2013-03-01

    An important issue of recent neuroscientific research is to understand the functional role of the phasic release of dopamine in the striatum, and in particular its relation to reinforcement learning. The literature is split between two alternative hypotheses: one considers phasic dopamine as a reward prediction error similar to the computational TD-error, whose function is to guide an animal to maximize future rewards; the other holds that phasic dopamine is a sensory prediction error signal that lets the animal discover and acquire novel actions. In this paper we propose an original hypothesis that integrates these two contrasting positions: according to our view phasic dopamine represents a TD-like reinforcement prediction error learning signal determined by both unexpected changes in the environment (temporary, intrinsic reinforcements) and biological rewards (permanent, extrinsic reinforcements). Accordingly, dopamine plays the functional role of driving both the discovery and acquisition of novel actions and the maximization of future rewards. To validate our hypothesis we perform a series of experiments with a simulated robotic system that has to learn different skills in order to get rewards. We compare different versions of the system in which we vary the composition of the learning signal. The results show that only the system reinforced by both extrinsic and intrinsic reinforcements is able to reach high performance in sufficiently complex conditions.

  10. An open-source LabVIEW application toolkit for phasic heart rate analysis in psychophysiological research.

    PubMed

    Duley, Aaron R; Janelle, Christopher M; Coombes, Stephen A

    2004-11-01

    The cardiovascular system has been extensively measured in a variety of research and clinical domains. Despite technological and methodological advances in cardiovascular science, the analysis and evaluation of phasic changes in heart rate persists as a way to assess numerous psychological concomitants. Some researchers, however, have pointed to constraints on data analysis when evaluating cardiac activity indexed by heart rate or heart period. Thus, an off-line application toolkit for heart rate analysis is presented. The program, written with National Instruments' LabVIEW, incorporates a variety of tools for off-line extraction and analysis of heart rate data. Current methods and issues concerning heart rate analysis are highlighted, and how the toolkit provides a flexible environment to ameliorate common problems that typically lead to trial rejection is discussed. Source code for this program may be downloaded from the Psychonomic Society Web archive at www.psychonomic.org/archive/.

  11. Depressive-like effects of the kappa opioid receptor agonist salvinorin A are associated with decreased phasic dopamine release in the nucleus accumbens

    PubMed Central

    Ebner, Stephanie R.; Roitman, Mitchell F.; Potter, David N.; Rachlin, Anna B.; Chartoff, Elena H.

    2010-01-01

    Rationale Kappa opioid receptors (KORs) have been implicated in depressive-like states associated with chronic administration of drugs of abuse and stress. Although KOR agonists decrease dopamine in the nucleus accumbens (NAc), KOR modulation of phasic dopamine release in the core and shell subregions of the NAc—which have distinct roles in reward processing—remains poorly understood. Objectives Studies were designed to examine whether the time course of effects of KOR activation on phasic dopamine release in the NAc core or shell are similar to effects on motivated behavior. Methods The effect of systemic administration of the KOR agonist salvinorin A (salvA)—at a dose (2.0 mg/kg) previously determined to have depressive-like effects—was measured on electrically evoked phasic dopamine release in the NAc core or shell of awake and behaving rats using fast scan cyclic voltammetry. In parallel, the effects of salvA on intracranial self-stimulation (ICSS) and sucrose-reinforced responding were assessed. For comparison, a threshold dose of salvA (0.25 mg/kg) was also tested. Results The active, but not threshold, dose of salvA significantly decreased phasic dopamine release without affecting dopamine reuptake in the NAc core and shell. SalvA increased ICSS thresholds and significantly lowered breakpoint on the progressive ratio schedule, indicating a decrease in motivation. The time course of the KOR-mediated decrease in dopamine in the core was qualitatively similar to the effects on motivated behavior. Conclusions These data suggest that the effects of KOR activation on motivation are due, in part, to inhibition of phasic dopamine signaling in the NAc core. PMID:20372879

  12. Cocaine Self-Administration Experience Induces Pathological Phasic Accumbens Dopamine Signals and Abnormal Incentive Behaviors in Drug-Abstinent Rats

    PubMed Central

    Wang, Xuefei; Sugam, Jonathan A.; Carelli, Regina M.

    2016-01-01

    Chronic exposure to drugs of abuse is linked to long-lasting alterations in the function of limbic system structures, including the nucleus accumbens (NAc). Although cocaine acts via dopaminergic mechanisms within the NAc, less is known about whether phasic dopamine (DA) signaling in the NAc is altered in animals with cocaine self-administration experience or if these animals learn and interact normally with stimuli in their environment. Here, separate groups of rats self-administered either intravenous cocaine or water to a receptacle (controls), followed by 30 d of enforced abstinence. Next, all rats learned an appetitive Pavlovian discrimination and voltammetric recordings of real-time DA release were taken in either the NAc core or shell of cocaine and control subjects. Cocaine experience differentially impaired DA signaling in the core and shell relative to controls. Although phasic DA signals in the shell were essentially abolished for all stimuli, in the core, DA did not distinguish between cues and was abnormally biased toward reward delivery. Further, cocaine rats were unable to learn higher-order associations and even altered simple conditioned approach behaviors, displaying enhanced preoccupation with cue-associated stimuli (sign-tracking; ST) but diminished time at the food cup awaiting reward delivery (goal-tracking). Critically, whereas control DA signaling correlated with ST behaviors, cocaine experience abolished this relationship. These findings show that cocaine has persistent, differential, and pathological effects on both DA signaling and DA-dependent behaviors and suggest that psychostimulant experience may remodel the very circuits that bias organisms toward repeated relapse. SIGNIFICANCE STATEMENT Relapsing to drug abuse despite periods of abstinence and sincere attempts to quit is one of the most pernicious facets of addiction. Unfortunately, little is known about how the dopamine (DA) system functions after periods of drug abstinence

  13. Muscle afferent potential (`A-wave') in the surface electromyogram of a phasic stretch reflex in normal humans

    PubMed Central

    Clarke, Alex. M.; Michie, Patricia T.; Glue, Leonard C. T.

    1972-01-01

    The experiments reported in this paper tested the hypothesis that the afferent potential elicited by a tendon tap in an isometrically recorded phasic stretch reflex can be detected in the surface EMG of normal humans when appropriate techniques are used. These techniques involved (1) training the subjects to relax mentally and physically so that the EMG was silent before and immediately after the diphasic MAP which reflects a highly synchronous discharge of afferent impulses from low threshold muscle stretch receptors after a tendon tap, and (2) using a data retrieval computer to summate stimulus-locked potentials in the EMG over a series of 16 samples using taps of uniform peak force and duration on the Achilles tendon to elicit the tendon jerk in the calf muscles. A discrete, diphasic potential (`A-wave') was recorded from EMG electrodes placed on the surface of the skin over the medial gastrocnemius muscle. The `A-wave' afferent potential had the opposite polarity to the corresponding efferent MAP. Under control conditions of relaxation the `A-wave' had a latency after the onset of the tap of 2 msec, the peak to peak amplitude was of the order of 5 μV and the duration was in the range of 6 to 10 msec. Further experiments were conducted to show that the `A-wave' (1) was not an artefact of the instrumentation used, (2) had a threshold at low intensities of stimulation, and (3) could be reliably augmented by using a Jendrassik manoeuvre compared with the potential observed during control (relaxation) conditions. The results support the conclusion that the `A-wave' emanates from the pool of muscle spindles which discharges impulses along group Ia nerve fibres in response to the phasic stretch stimulus because the primary ending of the spindles is known to initiate the stretch reflex and the spindles can be sensitized by fusimotor impulses so that their threshold is lowered as a result of a Jendrassik manoeuvre. The finding has important implications for the

  14. Phasic-to-tonic shift in trunk muscle activity relative to walking during low-impact weight bearing exercise

    NASA Astrophysics Data System (ADS)

    Caplan, Nick; Gibbon, Karl; Hibbs, Angela; Evetts, Simon; Debuse, Dorothée

    2014-11-01

    The aim of this study was to investigate the influence of an exercise device, designed to improve the function of lumbopelvic muscles via low-impact weight-bearing exercise, on electromyographic (EMG) activity of lumbopelvic, including abdominal muscles. Surface EMG activity was collected from lumbar multifidus (LM), erector spinae (ES), internal oblique (IO), external oblique (EO) and rectus abdominis (RA) during overground walking (OW) and exercise device (EX) conditions. During walking, most muscles showed peaks in activity which were not seen during EX. Spinal extensors (LM, ES) were more active in EX. Internal oblique and RA were less active in EX. In EX, LM and ES were active for longer than during OW. Conversely, EO and RA were active for a shorter duration in EX than OW. The exercise device showed a phasic-to-tonic shift in activation of both local and global lumbopelvic muscles and promoted increased activation of spinal extensors in relation to walking. These features could make the exercise device a useful rehabilitative tool for populations with lumbopelvic muscle atrophy and dysfunction, including those recovering from deconditioning due to long-term bed rest and microgravity in astronauts.

  15. Superior perception of phasic physiological arousal and the detrimental consequences of the conviction to be aroused on worrying and metacognitions in GAD.

    PubMed

    Andor, Tanja; Gerlach, Alexander L; Rist, Fred

    2008-02-01

    Although people suffering from generalized anxiety disorder (GAD) often report arousal symptoms, psychophysiological studies show no evidence of autonomic hyperarousal. Hypersensitivity toward and catastrophic interpretation of phasic arousal cues may explain this discrepancy. The authors tested (a) whether GAD sufferers perceive nonspecific skin conductance fluctuations (NSCFs), an indicator of phasic autonomic arousal, better than controls do and (b) whether the conviction to be aroused contributes to the maintenance of worrying and metacognitive beliefs about worrying. Thirty-three GAD sufferers and 34 healthy controls participated in 2 experiments. In Experiment 1, participants were asked to detect their own NSCFs during a signal detection task. GAD sufferers accurately detected more of their NSCFs than did controls, who tended to miss NSCFs. In Experiment 2, participants were instructed to relax following worry induction. While relaxing, they received nonveridical feedback indicating either arousal or relaxation. Arousal feedback conserved negative metacognitive beliefs regarding worrying and also maintained negative mood and worry exclusively in GAD participants. These findings suggest that superior perception of phasic arousal cues and their catastrophic misinterpretation increases worrying, negative metacognitive beliefs about worrying, and anxious mood in GAD. PMID:18266497

  16. The pattern of myometrial invasion as a predictor of lymph node metastasis or extrauterine disease in low-grade endometrial carcinoma.

    PubMed

    Euscher, Elizabeth; Fox, Patricia; Bassett, Roland; Al-Ghawi, Hayma; Ali-Fehmi, Rouba; Barbuto, Denise; Djordjevic, Bojana; Frauenhoffer, Elizabeth; Kim, Insun; Hong, Sun Rang; Montiel, Delia; Moschiano, Elizabeth; Roma, Andres; Silva, Elvio; Malpica, Anais

    2013-11-01

    The purpose of this study was to examine predictors of lymph node (LN) metastases or extrauterine disease (ED) in low-grade (FIGO grade 1 or 2) endometrioid carcinoma (LGEC) in a multi-institutional setting. For LGEC with and without LN metastasis or ED, each of the 9 participating institutions evaluated patients' age, tumor size, myometrial invasion (MI), FIGO grade, % solid component, the presence or absence of papillary architecture, microcystic, elongated, and fragmented glands (MELF), single-cell/cell-cluster invasion (SCI), lymphovascular invasion (LVI), lower uterine segment (LUS) and cervical stromal (CX) involvement, and numbers of pelvic and para-aortic LNs sampled. A total of 304 cases were reviewed: LN(+) or ED(+), 96; LN(-)/ED(-), 208. Patients' ages ranged from 23 to 91 years (median 61 y). Table 1 summarizes the histopathologic variables that were noted for the LN(+) or ED(+) group: tumor size ≥2 cm, 93/96 (97%); MI>50%, 54/96 (56%); MELF, 67/96 (70%); SCI, 33/96 (34%); LVI, 79/96 (82%); >20% solid, 65/96 (68%); papillary architecture present, 68/96 (72%); LUS involved, 64/96 (67%); and CX involved, 41/96 (43%). For the LN(-)/ED(-) group, the results were as follows: tumor size ≥2 cm, 152/208 (73%); MI>50%, 56/208 (27%); MELF, 79/208 (38%); SCI, 19/208 (9%); LVI, 56/208 (27%); >20% solid, 160/208 (77%); papillary architecture present, 122/208 (59%); LUS involved, 77/208 (37%); CX involved, 24/208 (12%). There was no evidence of a difference in the number of pelvic or para-aortic LNs sampled between groups (P=0.9 and 0.1, respectively). After multivariate analysis, the depth of MI, CX involvement, LVI, and SCI emerged as significant predictors of advanced-stage disease. Although univariate analysis pointed to LUS involvement, MELF pattern of invasion, and papillary architecture as possible predictors of advanced-stage disease, these were not shown to be significant by multivariate analysis. This study validates MI, CX involvement, and LVI as

  17. Bi-phasic trends in mercury concentrations in blood of Wisconsin common loons during 1992–2010

    USGS Publications Warehouse

    Meyer, Michael W.; Rasmussen, Paul W.; Watras, Carl J.; Fevold, Brick M.; Kenow, Kevin P.

    2011-01-01

    Wisconsin Department of Natural Resources (WDNR) assessed the ecological risk of mercury (Hg) in aquatic systems by monitoring common loon (Gavia immer) population dynamics and blood Hg concentrations. We report temporal trends in blood Hg concentrations based on 334 samples collected from adults recaptured in subsequent years (resampled 2-9 times) and from 421 blood samples of chicks collected at lakes resampled 2-8 times 1992-2010.. Temporal trends were identified with generalized additive mixed effects models (GAMMs) and mixed effects models to account for the potential lack of independence among observations from the same loon or same lake. Trend analyses indicated that Hg concentrations in the blood of Wisconsin loons declined over the period 1992-2000, and increased during 2002-2010, but not to the level observed in the early 1990s. The best fitting linear mixed effects model included separate trends for the two time periods. The estimated trend in Hg concentration among the adult loon population during 1992-2000 was -2.6% per year and the estimated trend during 2002-2010 was +1.8% per year; chick blood Hg concentrations decreased by -6.5% per year during 1992-2000, but increased 1.8% per year during 2002-2010. This bi-phasic pattern is similar to trends observed for concentrations of methylmercury (meHg) and SO4 in lake water of a well studied seepage lake (Little Rock Lake, Vilas County) within our study area. A cause-effect relationship between these independent trends is hypothesized.

  18. Selective depletion of spinal monoamines changes the rat soleus EMG from a tonic to a more phasic pattern.

    PubMed Central

    Kiehn, O; Erdal, J; Eken, T; Bruhn, T

    1996-01-01

    1. To assess the role of descending monoaminergic pathways for motor activity long-lasting EMG recordings were performed from the adult soleus muscle before and after selective depletion of spinal monoamines. 2. Rats were chronically implanted with an intrathecal catheter placed in the lumbar subarachnoid space and gross-EMG recording electrodes in the soleus muscle. EMG recordings were performed in control conditions and at different times after intrathecal administration of either 40-55 micrograms 5,6-dihydroxytryptamine (5,6-DHT) and 40-55 micrograms 6-hydroxydopamine (6-OHDA) or 80 micrograms 5,7-dihydroxytryptamine (5,7-DHT) alone. The depletions were evaluated biochemically in brains and spinal cords after recordings. 3. In agreement with previous studies the intrathecal administration of neurotoxins caused a reduction of the noradrenaline (NA) and serotonin (5-HT) content of the lumbar spinal cord to about 2-3% of control, with little or no changes in the monoamine content of the cortex. 4. In non-treated chronically catheterized rats the integrated rectified gross EMG displayed long-lasting EMG episodes composed of phasic high-amplitude events and tonic segments of varying duration and amplitude. 5. After intrathecal administration of neurotoxins the number of long-lasting gross-EMG episodes, the mean episode duration, and the total EMG activity per 24 h, were reduced. These changes were accompanied by a simultaneous increase both in the number of short-lasting EMG episodes and the total number of EMG episodes per 24 h period. The changes were apparent 5-6 days after drug administration and fully developed after 2-3 weeks. 6. No changes in general movement ability were observed, except that the denervated animals had a tendency to a less errect posture. 7. These results indicate that descending monoaminergic pathways are important for the maintained motor output in tonic hindlimb muscles. PMID:8730593

  19. Glycine and GABAA receptors mediate tonic and phasic inhibitory processes that contribute to prepulse inhibition in the goldfish startle network

    PubMed Central

    Curtin, Paul C. P.; Preuss, Thomas

    2015-01-01

    Prepulse inhibition (PPI) is understood as a sensorimotor gating process that attenuates sensory flow to the startle pathway during early stages (20–1000 ms) of information processing. Here, we applied in vivo electrophysiology and pharmacology to determine if PPI is mediated by glycine receptors (GlyRs) and/or GABAA receptors (GABAARs) in the goldfish auditory startle circuit. Specifically, we used selective antagonists to dissect the contributions of target receptors on sound-evoked postsynaptic potentials (PSPs) recorded in the neurons that initiate startle, the Mauthner-cells (M-cell). We found that strychnine, a GlyR antagonist, disrupted a fast-activated (5 ms) and rapidly (<50 ms) decaying (feed-forward) inhibitory process that contributes to PPI at 20 ms prepulse/pulse inter-stimulus intervals (ISI). Additionally we observed increases of the evoked postsynaptic potential (PSP) peak amplitude (+87.43 ± 21.53%, N = 9) and duration (+204 ± 48.91%, N = 9). In contrast, treatment with bicuculline, a GABAAR antagonist, caused a general reduction in PPI across all tested interstimulus intervals (ISIs) (20–500 ms). Bicuculline also increased PSP peak amplitude (+133.8 ± 10.3%, N = 5) and PSP duration (+284.95 ± 65.64%, N = 5). Treatment with either antagonist also tonically increased post-synaptic excitability in the M-cells, reflected by an increase in the magnitude of antidromically-evoked action potentials (APs) by 15.07 ± 3.21%, N = 7 and 16.23 ± 7.08%, N = 5 for strychnine and bicuculline, respectively. These results suggest that GABAARs and GlyRs are functionally segregated to short- and longer-lasting sound-evoked (phasic) inhibitory processes that contribute to PPI, with the mediation of tonic inhibition by both receptor systems being critical for gain control within the M-cell startle circuit. PMID:25852486

  20. Store-operated Ca2+ entry and depolarization explain the anomalous behaviour of myometrial SR: Effects of SERCA inhibition on electrical activity, Ca2+ and force

    PubMed Central

    Noble, Debbie; Borysova, Lyudmyla; Wray, Susan; Burdyga, Theodor

    2014-01-01

    In the myometrium SR Ca2+ depletion promotes an increase in force but unlike several other smooth muscles, there is no Ca2+ sparks-STOCs coupling mechanism to explain this. Given the importance of the control of contractility for successful parturition, we have examined, in pregnant rat myometrium, the effects of SR Ca2+-ATPase (SERCA) inhibition on the temporal relationship between action potentials, Ca2+ transients and force. Simultaneous recording of electrical activity, calcium and force showed that SERCA inhibition, by cyclopiazonic acid (CPA 20 μM), caused time-dependent changes in excitability, most noticeably depolarization and elevations of baseline [Ca2+]i and force. At the onset of these changes there was a prolongation of the bursts of action potentials and a corresponding series of Ca2+ spikes, which increased the amplitude and duration of contractions. As the rise of baseline Ca2+ and depolarization continued a point was reached when electrical and Ca2+ spikes and phasic contractions ceased, and a maintained, tonic force and Ca2+ was produced. Lanthanum, a non-selective blocker of store-operated Ca2+ entry, but not the L-type Ca2+ channel blocker nifedipine (1–10 μM), could abolish the maintained force and calcium. Application of the agonist, carbachol, produced similar effects to CPA, i.e. depolarization, elevation of force and calcium. A brief, high concentration of carbachol, to cause SR Ca2+ depletion without eliciting receptor-operated channel opening, also produced these results. The data obtained suggest that in pregnant rats SR Ca2+ release is coupled to marked Ca2+ entry, via store operated Ca2+ channels, leading to depolarization and enhanced electrical and mechanical activity. PMID:25084623

  1. Lymph-vascular space involvement and outer one-third myometrial invasion are strong predictors of distant haematogeneous failures in patients with stage I-II endometrioid-type endometrial cancer.

    PubMed

    Gadducci, Angiolo; Cavazzana, Andrea; Cosio, Stefania; DI Cristofano, Claudio; Tana, Roberta; Fanucchi, Antonio; Teti, Giancarlo; Cristofani, Renza; Genazzani, Andrea Riccardo

    2009-05-01

    The aim of this retrospective study was to assess the predictive value of different clinicopathological variables (patient age, tumour size, FIGO grade, myometrial invasion, lymph-vascular space involvement [LVSI], invasion margins, peri-tumour phlogistic infiltrate and mitotic activity) for the risk of distant haematogenous recurrences in patients with endometrioid-type stage Ib-II endometrial cancer. Between August 1990 and April 2005, 259 patients had undergone laparotomy, peritoneal washing, total abdominal hysterectomy and bilateral salpingo-oophorectomy, with or without pelvic +/- para-aortic lymphadenectomy for endometrioid-type endometrial cancer. Thirty-six (13.9%) patients had developed recurrent disease after a median time of 17 months (range, 2-128 months). The relapse had been locoregional in 9, distant in 21 and both locoregional plus distant in 6 cases. This study assessed 12 patients with FIGO stage Ib-II disease who had developed distant haematogenous recurrences and 20 randomly chosen control patients with FIGO stage Ib-II disease who had remained recurrence-free after a median follow-up of 52 months (range, 37-66 months). Adjuvant therapy had been: no further treatment in 15 patients, external pelvic irradiation in 14 patients, adjuvant external pelvic irradiation plus brachytherapy in 2 patients and platinum-based chemotherapy followed by external pelvic irradiation in 1 patient. The site of distant failure had been the lung in 9 patients, liver in 2 patients and lung plus liver in 1 patient. A concomitant locoregional relapse (vagina or lymph nodes) had occurred in 3 patients. The median interval between surgery and the development of distant failure had been 16.5 months (range, 5-113 months). On univariate analysis, a higher incidence of FIGO grade 3 (50% versus 10%, p=0.0114), outer one-third myometrial invasion (91.7% versus 35.0%, p=0.0051) and LVSI (75.0.% versus 20.0%, p=0.0022) was found in the patients who had developed distant

  2. Pontine regulation of REM sleep components in cats: integrity of the pedunculopontine tegmentum (PPT) is important for phasic events but unnecessary for atonia during REM sleep.

    PubMed

    Shouse, M N; Siegel, J M

    1992-01-31

    Transection, lesion and unit recording studies have localized rapid eye movement (REM) sleep mechanisms to the pons. Recent work has emphasized the role of pontine cholinergic cells, especially those of the pedunculopontine tegmentum (PPT). The present study differentiated REM sleep deficits associated with lesions of the PPT from other pontine regions implicated in REM sleep generation, including those with predominantly cholinergic vs non-cholinergic cells. Twelve hour polygraphic recordings were obtained in 18 cats before and 1-2 weeks after bilateral electrolytic or radio frequency lesions of either: (1) PPT, which contains the dorsolateral pontine cholinergic cell column; (2) laterodorsal tegmental nucleus (LDT), which contains the dorsomedial pontine cholinergic cell column; (3) locus ceruleus (LC), which contains mostly noradrenergic cells; or (4) subceruleus (LC alpha, peri-LC alpha and the lateral tegmental field), which also contains predominantly noncholinergic cells. There were three main findings: (i) Only lesions of PPT and subceruleus significantly affected REM sleep time. These lesions produced comparable reductions in REM sleep time but influenced REM sleep components quite differently: (ii) PPT lesions, estimated to damage 90 +/- 4% of cholinergic cells, reduced the number of REM sleep entrances and phasic events, including ponto-geniculooccipital (PGO) spikes and rapid eye movements (REMs), but did not prevent complete atonia during REM sleep: (iii) Subceruleus lesions eliminated atonia during REM sleep. Mobility appeared to arouse the cat prematurely from REM sleep and may explain the brief duration of REM sleep epochs seen exclusively in this group. Despite the reduced amount of REM sleep, the total number of PGO spikes and REM sleep entrances increased over baseline values. Collectively, the results distinguish pontine loci regulating phasic events vs atonia. PPT lesions reduced phasic events, whereas subceruleus lesions created REM sleep

  3. Anatase/rutile bi-phasic titanium dioxide nanoparticles for photocatalytic applications enhanced by nitrogen doping and platinum nano-islands.

    PubMed

    Bear, Joseph C; Gomez, Virginia; Kefallinos, Nikolaos S; McGettrick, James D; Barron, Andrew R; Dunnill, Charles W

    2015-12-15

    Titanium dioxide (TiO2) bi-phasic powders with individual particles containing an anatase and rutile hetero-junction have been prepared using a sequential layer sol-gel deposition technique to soluble substrates. Sequential thin films of rutile and subsequently anatase TiO2 were deposited onto sodium chloride substrates yielding extremely fragile composite layered discs that fractured into "Janus-like" like powders on substrate dissolution. Nitrogen doped and platinum sputtered analogues were also prepared, and analysed for photocatalytic potential using the photodegradation of Rhodamine B, a model organic pollutant under UV and visible light irradiation. The materials were characterised using X-ray diffraction, X-ray photoelectron spectroscopy, energy dispersive X-ray spectroscopy, Raman spectroscopy and scanning electron microscopy. This paper sheds light on the relationship between anatase and rutile materials when in direct contact and demonstrates a robust method for the synthesis of bi-phasic nanoparticles, ostensibly of any two materials, for photocatalytic reactions or otherwise.

  4. The Cortisol Paradox of Trauma-Related Disorders: Lower Phasic Responses but Higher Tonic Levels of Cortisol Are Associated with Sexual Abuse in Childhood

    PubMed Central

    Schalinski, Inga; Elbert, Thomas; Steudte-Schmiedgen, Susann; Kirschbaum, Clemens

    2015-01-01

    Objectives Inconsistent findings exist for the activity of the hypothalamic-pituitary-adrenal (HPA) axis in patients with stress related disorders. Recent studies point towards early life stress as a potential modulator. Methods We investigated the impact of childhood sexual abuse on phasic (saliva cortisol reactivity) and tonic (hair cortisol) regulation. Furthermore, we assessed predictors on cortisol accumulation in hair. Women (N = 43) with stress-related disorders underwent a standardized assessment of idiographic adverse and traumatic experiences and psychopathology, while measuring salivary cortisol and, heart rate and blood pressure. Results Comparing women with and without childhood sexual abuse revealed lower rates of responders and distinct levels of salivary cortisol to the interview in conjunction with a lower heart rate for the abused group. Childhood adversities, traumatic experiences, and depression contributed to higher hair cortisol levels. Conclusions Our finding of lower response rate and distinct salivary cortisol pattern in individuals with childhood sexual abuse compared to individuals without early sexual abuse supports the role of environmental programming for the HPA axis. Both, childhood adversities and traumatic stress emerge as crucial factors for long-term cortisol secretion. Lower or suppressed phasic cortisol responses to trauma-related stimuli may therefore be associated with higher tonic values. Thus, early exposure to adversities may result in a biological distinct phenotype in adult patients with stress-related disorders. PMID:26317554

  5. Selective Participation of the Bed Nucleus of the Stria Terminalis and CRF in Sustained Anxiety-Like versus Phasic Fear-Like Responses

    PubMed Central

    Walker, D. L.; Miles, L. A.; Davis, M.

    2009-01-01

    The medial division of the central nucleus of the amygdala (CeAM) and the lateral division of the bed nucleus of the stria terminalis (BNSTL) are closely related. Both receive projections from the basolateral amygdala (BLA) and both project to brain areas that mediate fear-influenced behaviors. In contrast to CeAM however, initial attempts to implicate the BNST in conditioned fear responses were largely unsuccessful. More recent studies have shown that the BNST does participate in some types of anxiety and stress responses. Here, we review evidence suggesting that the CeAM and BNSTL are functionally complementary, with CeAM mediating short- but not long-duration threat responses (i.e., phasic fear) and BNSTL mediating long- but not short-duration responses (sustained fear or ‘anxiety’). We also review findings implicating the stress-related peptide corticotropin-releasing factor (CRF) in sustained but not phasic threat responses, and attempt to integrate these findings into a neural circuit model which accounts for these and related observations. PMID:19595731

  6. Electrocatalytic Production of C3-C4 Compounds by Conversion of CO2 on a Chloride-Induced Bi-Phasic Cu2O-Cu Catalyst.

    PubMed

    Lee, Seunghwa; Kim, Dahee; Lee, Jaeyoung

    2015-12-01

    Electrocatalytic conversion of carbon dioxide (CO2) has recently received considerable attention as one of the most feasible CO2 utilization techniques. In particular, copper and copper-derived catalysts have exhibited the ability to produce a number of organic molecules from CO2. Herein, we report a chloride (Cl)-induced bi-phasic cuprous oxide (Cu2O) and metallic copper (Cu) electrode (Cu2OCl) as an efficient catalyst for the formation of high-carbon organic molecules by CO2 conversion, and identify the origin of electroselectivity toward the formation of high-carbon organic compounds. The Cu2OCl electrocatalyst results in the preferential formation of multi-carbon fuels, including n-propanol and n-butane C3-C4 compounds. We propose that the remarkable electrocatalytic conversion behavior is due to the favorable affinity between the reaction intermediates and the catalytic surface. PMID:26473324

  7. Electrocatalytic Production of C3-C4 Compounds by Conversion of CO2 on a Chloride-Induced Bi-Phasic Cu2O-Cu Catalyst.

    PubMed

    Lee, Seunghwa; Kim, Dahee; Lee, Jaeyoung

    2015-12-01

    Electrocatalytic conversion of carbon dioxide (CO2) has recently received considerable attention as one of the most feasible CO2 utilization techniques. In particular, copper and copper-derived catalysts have exhibited the ability to produce a number of organic molecules from CO2. Herein, we report a chloride (Cl)-induced bi-phasic cuprous oxide (Cu2O) and metallic copper (Cu) electrode (Cu2OCl) as an efficient catalyst for the formation of high-carbon organic molecules by CO2 conversion, and identify the origin of electroselectivity toward the formation of high-carbon organic compounds. The Cu2OCl electrocatalyst results in the preferential formation of multi-carbon fuels, including n-propanol and n-butane C3-C4 compounds. We propose that the remarkable electrocatalytic conversion behavior is due to the favorable affinity between the reaction intermediates and the catalytic surface.

  8. Optogenetic stimulation of VTA dopamine neurons reveals that tonic but not phasic patterns of dopamine transmission reduce ethanol self-administration.

    PubMed

    Bass, Caroline E; Grinevich, Valentina P; Gioia, Dominic; Day-Brown, Jonathan D; Bonin, Keith D; Stuber, Garret D; Weiner, Jeff L; Budygin, Evgeny A

    2013-01-01

    There is compelling evidence that acute ethanol exposure stimulates ventral tegmental area (VTA) dopamine cell activity and that VTA-dependent dopamine release in terminal fields within the nucleus accumbens plays an integral role in the regulation of ethanol drinking behaviors. Unfortunately, due to technical limitations, the specific temporal dynamics linking VTA dopamine cell activation and ethanol self-administration are not known. In fact, establishing a causal link between specific patterns of dopamine transmission and ethanol drinking behaviors has proven elusive. Here, we sought to address these gaps in our knowledge using a newly developed viral-mediated gene delivery strategy to selectively express Channelrhodopsin-2 (ChR2) on dopamine cells in the VTA of wild-type rats. We then used this approach to precisely control VTA dopamine transmission during voluntary ethanol drinking sessions. The results confirmed that ChR2 was selectively expressed on VTA dopamine cells and delivery of blue light pulses to the VTA induced dopamine release in accumbal terminal fields with very high temporal and spatial precision. Brief high frequency VTA stimulation induced phasic patterns of dopamine release in the nucleus accumbens. Lower frequency stimulation, applied for longer periods mimicked tonic increases in accumbal dopamine. Notably, using this optogenetic approach in rats engaged in an intermittent ethanol drinking procedure, we found that tonic, but not phasic, stimulation of VTA dopamine cells selectively attenuated ethanol drinking behaviors. Collectively, these data demonstrate the effectiveness of a novel viral targeting strategy that can be used to restrict opsin expression to dopamine cells in standard outbred animals and provide the first causal evidence demonstrating that tonic activation of VTA dopamine neurons selectively decreases ethanol self-administration behaviors.

  9. Slow Noise in the Period of a Biological Oscillator Underlies Gradual Trends and Abrupt Transitions in Phasic Relationships in Hybrid Neural Networks

    PubMed Central

    Norman, Sharon E.; Butera, Robert J.; Canavier, Carmen C.

    2014-01-01

    In order to study the ability of coupled neural oscillators to synchronize in the presence of intrinsic as opposed to synaptic noise, we constructed hybrid circuits consisting of one biological and one computational model neuron with reciprocal synaptic inhibition using the dynamic clamp. Uncoupled, both neurons fired periodic trains of action potentials. Most coupled circuits exhibited qualitative changes between one-to-one phase-locking with fairly constant phasic relationships and phase slipping with a constant progression in the phasic relationships across cycles. The phase resetting curve (PRC) and intrinsic periods were measured for both neurons, and used to construct a map of the firing intervals for both the coupled and externally forced (PRC measurement) conditions. For the coupled network, a stable fixed point of the map predicted phase locking, and its absence produced phase slipping. Repetitive application of the map was used to calibrate different noise models to simultaneously fit the noise level in the measurement of the PRC and the dynamics of the hybrid circuit experiments. Only a noise model that added history-dependent variability to the intrinsic period could fit both data sets with the same parameter values, as well as capture bifurcations in the fixed points of the map that cause switching between slipping and locking. We conclude that the biological neurons in our study have slowly-fluctuating stochastic dynamics that confer history dependence on the period. Theoretical results to date on the behavior of ensembles of noisy biological oscillators may require re-evaluation to account for transitions induced by slow noise dynamics. PMID:24830924

  10. Episodic Social Stress-Escalated Cocaine Self-Administration: Role of Phasic and Tonic Corticotropin Releasing Factor in the Anterior and Posterior Ventral Tegmental Area

    PubMed Central

    Boyson, Christopher O.; Montagud-Romero, Sandra; Stein, Dirson J.; Gobrogge, Kyle L.; DeBold, Joseph F.; Miczek, Klaus A.

    2016-01-01

    Intermittent social defeat stress escalates later cocaine self-administration. Reward and stress both activate ventral tegmental area (VTA) dopamine neurons, increasing downstream extracellular dopamine concentration in the medial prefrontal cortex and nucleus accumbens. The stress neuropeptide corticotropin releasing factor (CRF) and its receptors (CRF-R1, CRF-R2) are located in the VTA and influence dopaminergic activity. These experiments explore how CRF release and the activation of its receptors within the VTA both during and after stress influence later cocaine self-administration in rats. In vivo microdialysis of CRF in the VTA demonstrated that CRF is phasically released in the posterior VTA (pVTA) during acute defeat, but, with repeated defeat, CRF is recruited into the anterior VTA (aVTA) and CRF tone is increased in both subregions. Intra-VTA antagonism of CRF-R1 in the pVTA and CRF-R2 in the aVTA during each social defeat prevented escalated cocaine self-administration in a 24 h “binge.” VTA CRF continues to influence cocaine seeking in stressed animals long after social defeat exposure. Unlike nonstressed controls, previously stressed rats show significant cocaine seeking after 15 d of forced abstinence. Previously stressed rats continue to express elevated CRF tone within the VTA and antagonism of pVTA CRF-R1 or aVTA CRF-R2 reverses cocaine seeking. In conclusion, these experiments demonstrate neuroadaptive changes in tonic and phasic CRF with repeated stress, that CRF release during stress may contribute to later escalated cocaine taking, and that persistently elevated CRF tone in the VTA may drive later cocaine seeking through increased activation of pVTA CRF-R1 and aVTA CRF-R2. SIGNIFICANCE STATEMENT Corticotropin releasing factor (CRF) within the ventral tegmental area (VTA) has emerged as a likely candidate molecule underlying the fundamental link between stress history and escalated drug self-administration. However, the nature of CRF

  11. Bi-phasic expression of Heterochromatin Protein 1 (HP1) during breast cancer progression: Potential roles of HP1 and chromatin structure in tumorigenesis

    PubMed Central

    Lee, Young-Ho; Ann, David K.

    2015-01-01

    Epigenetics in cancer prognosis and therapy is gaining recognition in recent years. Breast cancer is a genetic disease harboring numerous genetic mutations, including tumor suppressor BRCA1 and BRCA2 mutations. However, the functions of BRCA1 in cancer cells are also altered by non-genetic mechanisms, including DNA methylation and chromatin structure. Therefore, identification of epigenetic markers for breast cancer is very important for early diagnosis and effective therapy. This review focuses on recent findings on the roles of Heterochromatin protein 1 (HP1) in BRCA1 functions and breast cancer progression. We previously showed that BRCA1 function and breast cancer progression are frequently associated with HP1 expression level and potentially with chromatin structure. Herein, we suggest that bi-phasic expression of HP1 during breast cancer progression indicates dual roles of HP1 in tumorigenesis. Exploiting differential HP1 expression in tumors could lead to effective cancer therapy. Re-setting the chromatin structure may be a critical step for high-efficiency cancer therapy for many breast cancer patients. PMID:26082944

  12. Critical points in the forelimb fictive locomotor cycle and motor coordination: effects of phasic retractions and protractions of the shoulder in the cat.

    PubMed

    Saltiel, Philippe; Rossignol, Serge

    2004-09-01

    This study investigates the responses to phasic shoulder retractions or protractions given at different times in the fictive locomotor cycle of the forelimbs of decerebrate cats. Generally, the responses in flexor and extensor muscles acting at the shoulder or elbow were bilaterally coordinated according to a negative feedback scheme. Perturbations in the direction of the movements that would have taken place if the animal had not been paralyzed tended to shorten the duration of the burst of activity of the muscles active during that phase and vice versa in the opposite phase. Changes in response patterns took place around critical points corresponding to the critical points B-D described in the companion paper using tonic perturbations of the limb. Past point C, at 58% of the ipsilateral extensor burst, protractions no longer prolonged the burst and no longer delayed onset of the contralateral extensor. At point B, occurring at 41% of the contralateral extensor burst, ipsilateral protractions maximally shortened the ipsilateral flexor phase, advancing ipsilateral extensor onset (point D) to point C of the contralateral extensor burst. During a critical period from the end of the ipsilateral flexor (point D) until the contralateral flexor onset, retractions elicited two alternative responses. Either the contralateral extensor activity was abolished and the contralateral flexor turned on, or it persisted for another cycle. We argue that the critical points found here correspond to critical biomechanical events in real locomotion and may underlie a phase-dependent motor coordination.

  13. Wheel running reduces high-fat diet intake, preference and mu-opioid agonist stimulated intake.

    PubMed

    Liang, Nu-Chu; Bello, Nicholas T; Moran, Timothy H

    2015-05-01

    The ranges of mechanisms by which exercise affects energy balance remain unclear. One potential mechanism may be that exercise reduces intake and preference for highly palatable, energy dense fatty foods. The current study used a rodent wheel running model to determine whether and how physical activity affects HF diet intake/preference and reward signaling. Experiment 1 examined whether wheel running affected the ability of intracerebroventricular (ICV) μ opioid receptor agonist D-Ala2, NMe-Phe4, Glyol5-enkephalin (DAMGO) to increase HF diet intake. Experiment 2 examined the effects of wheel running on the intake of and preference for a previously preferred HF diet. We also assessed the effects of wheel running and diet choice on mesolimbic dopaminergic and opioidergic gene expression. Experiment 1 revealed that wheel running decreased the ability of ICV DAMGO administration to stimulate HF diet intake. Experiment 2 showed that wheel running suppressed weight gain and reduced intake and preference for a previously preferred HF diet. Furthermore, the mesolimbic gene expression profile of wheel running rats was different from that of their sedentary paired-fed controls but similar to that of sedentary rats with large HF diet consumption. These data suggest that alterations in preference for palatable, energy dense foods play a role in the effects of exercise on energy homeostasis. The gene expression results also suggest that the hedonic effects of exercise may substitute for food reward to limit food intake and suppress weight gain.

  14. CAR and PXR agonists stimulate hepatic bile acid and bilirubin detoxification and elimination pathways in mice.

    PubMed

    Wagner, Martin; Halilbasic, Emina; Marschall, Hanns-Ulrich; Zollner, Gernot; Fickert, Peter; Langner, Cord; Zatloukal, Kurt; Denk, Helmut; Trauner, Michael

    2005-08-01

    Induction of hepatic phase I/II detoxification enzymes and alternative excretory pumps may limit hepatocellular accumulation of toxic biliary compounds in cholestasis. Because the nuclear xenobiotic receptors constitutive androstane receptor (CAR) and pregnane X receptor (PXR) regulate involved enzymes and transporters, we aimed to induce adaptive alternative pathways with different CAR and PXR agonists in vivo. Mice were treated with the CAR agonists phenobarbital and 1,4-bis-[2-(3,5-dichlorpyridyloxy)]benzene, as well as the PXR agonists atorvastatin and pregnenolone-16alpha-carbonitrile. Hepatic bile acid and bilirubin-metabolizing/detoxifying enzymes (Cyp2b10, Cyp3a11, Ugt1a1, Sult2a1), their regulatory nuclear receptors (CAR, PXR, farnesoid X receptor), and bile acid/organic anion and lipid transporters (Ntcp, Oatp1,2,4, Bsep, Mrp2-4, Mdr2, Abcg5/8, Asbt) in the liver and kidney were analyzed via reverse-transcriptase polymerase chain reaction and Western blotting. Potential functional relevance was tested in common bile duct ligation (CBDL). CAR agonists induced Mrp2-4 and Oatp2; PXR agonists induced only Mrp3 and Oatp2. Both PXR and CAR agonists profoundly stimulated bile acid-hydroxylating/detoxifying enzymes Cyp3a11 and Cyp2b10. In addition, CAR agonists upregulated bile acid-sulfating Sult2a1 and bilirubin-glucuronidating Ugt1a1. These changes were accompanied by reduced serum levels of bilirubin and bile acids in healthy and CBDL mice and by increased levels of polyhydroxylated bile acids in serum and urine of cholestatic mice. Atorvastatin significantly increased Oatp2, Mdr2, and Asbt, while other transporters and enzymes were moderately affected. In conclusion, administration of specific CAR or PXR ligands results in coordinated stimulation of major hepatic bile acid/bilirubin metabolizing and detoxifying enzymes and hepatic key alternative efflux systems, effects that are predicted to counteract cholestasis. PMID:15986414

  15. Dendrite-selective redistribution of the chemokine receptor CXCR4 following agonist stimulation.

    PubMed

    Baudouin, Stéphane J; Pujol, Fabien; Nicot, Arnaud; Kitabgi, Patrick; Boudin, Hélène

    2006-10-01

    The chemokine SDF-1 is a secreted protein that plays a critical role in several aspects of neuron development through interaction with its unique receptor CXCR4. A key mechanism that controls neuron responsiveness to extracellular signals during neuronal growth is receptor endocytosis. Since we previously reported that SDF-1 regulates axon development without affecting the other neurites, we asked whether this could correlate with a compartment-selective trafficking of CXCR4. We thus studied CXCR4 behavior upon SDF-1 exposure in rat hippocampus slices and in transfected neuron cultures. A massive agonist-induced redistribution of CXCR4 in endosomes was observed in dendrites whereas no modification was evidenced in axons. Our data suggest that CXCR4 trafficking may play a role in mediating selective effects of SDF-1 on distinct neuronal membrane subdomains.

  16. Chronic levodopa treatment alters basal and dopamine agonist-stimulated cerebral glucose utilization

    SciTech Connect

    Engber, T.M.; Susel, Z.; Kuo, S.; Chase, T.N. )

    1990-12-01

    The effect of chronic levodopa administration on the functional activity of the basal ganglia and its output regions was evaluated by means of the 2-deoxyglucose (2-DG) autoradiographic technique in rats with a unilateral 6-hydroxydopamine lesion of the nigrostriatal pathway. The rates of local cerebral glucose utilization were studied under basal conditions as well as in response to challenge with a selective D1 or D2 dopamine-receptor agonist. Levodopa (100 mg/kg/d, i.p.) was administered for 19 d either continuously via infusion with an osmotic pump or intermittently by twice-daily injections. Following a 3-d washout, glucose utilization was found to be decreased by both levodopa regimens in the nucleus accumbens; intermittent levodopa also decreased glucose utilization in the entopeduncular nucleus, subthalamic nucleus, ventrolateral thalamus, ventromedial thalamus, ventroposterolateral thalamus, and lateral habenula. In control (lesioned and treated chronically with saline) rats, the D1 agonist SKF 38393 (5 mg/kg, i.v.) increased 2-DG uptake in the substantia nigra pars reticulata and entopeduncular nucleus ipsilateral to the lesion by 84% and 56%, respectively. Both continuous and intermittent levodopa blunted the SKF 38393-induced elevation in glucose metabolism in the substantia nigra pars reticulata, while intermittent levodopa also attenuated the increase in the entopeduncular nucleus. The D2 agonist quinpirole (0.4 mg/kg, i.v.) did not increase glucose utilization in any brain region in control animals; following intermittent levodopa treatment, however, quinpirole increased 2-DG uptake by 64% in the subthalamic nucleus and by 39% in the deep layers of the superior colliculus on the ipsilateral side.

  17. Non-psychoactive CB2 cannabinoid agonists stimulate neural progenitor proliferation.

    PubMed

    Palazuelos, Javier; Aguado, Tania; Egia, Ainara; Mechoulam, Raphael; Guzmán, Manuel; Galve-Roperh, Ismael

    2006-11-01

    Cannabinoids, the active components of marijuana and their endogenous counterparts, act on the brain and many other organs through the widely expressed CB1 cannabinoid receptor. In contrast, the CB2 cannabinoid receptor is abundant in the immune system and shows a restricted expression pattern in brain cells. CB2-selective agonists are, therefore, very attractive therapeutic agents as they do not cause CB1-mediated psychoactive effects. CB2 receptor expression in brain has been partially examined in differentiated cells, while its presence and function in neural progenitor cells remain unknown. Here we show that the CB2 receptor is expressed, both in vitro and in vivo, in neural progenitors from late embryonic stages to adult brain. Selective pharmacological activation of the CB2 receptor in vitro promotes neural progenitor cell proliferation and neurosphere generation, an action that is impaired in CB2-deficient cells. Accordingly, in vivo experiments evidence that hippocampal progenitor proliferation is increased by administration of the CB2-selective agonist HU-308. Moreover, impaired progenitor proliferation was observed in CB2-deficient mice both in normal conditions and on kainate-induced excitotoxicity. These findings provide a novel physiological role for the CB2 cannabinoid receptor and open a novel therapeutic avenue for manipulating neural progenitor cell fate.

  18. Store-operated Ca²⁺ entry and depolarization explain the anomalous behaviour of myometrial SR: effects of SERCA inhibition on electrical activity, Ca²⁺ and force.

    PubMed

    Noble, Debbie; Borysova, Lyudmyla; Wray, Susan; Burdyga, Theodor

    2014-09-01

    In the myometrium SR Ca(2+) depletion promotes an increase in force but unlike several other smooth muscles, there is no Ca(2+) sparks-STOCs coupling mechanism to explain this. Given the importance of the control of contractility for successful parturition, we have examined, in pregnant rat myometrium, the effects of SR Ca(2+)-ATPase (SERCA) inhibition on the temporal relationship between action potentials, Ca(2+) transients and force. Simultaneous recording of electrical activity, calcium and force showed that SERCA inhibition, by cyclopiazonic acid (CPA 20 μM), caused time-dependent changes in excitability, most noticeably depolarization and elevations of baseline [Ca(2+)]i and force. At the onset of these changes there was a prolongation of the bursts of action potentials and a corresponding series of Ca(2+) spikes, which increased the amplitude and duration of contractions. As the rise of baseline Ca(2+) and depolarization continued a point was reached when electrical and Ca(2+) spikes and phasic contractions ceased, and a maintained, tonic force and Ca(2+) was produced. Lanthanum, a non-selective blocker of store-operated Ca(2+) entry, but not the L-type Ca(2+) channel blocker nifedipine (1-10 μM), could abolish the maintained force and calcium. Application of the agonist, carbachol, produced similar effects to CPA, i.e. depolarization, elevation of force and calcium. A brief, high concentration of carbachol, to cause SR Ca(2+) depletion without eliciting receptor-operated channel opening, also produced these results. The data obtained suggest that in pregnant rats SR Ca(2+) release is coupled to marked Ca(2+) entry, via store operated Ca(2+) channels, leading to depolarization and enhanced electrical and mechanical activity. PMID:25084623

  19. Nitric oxide regulation of monkey myometrial contractility

    PubMed Central

    Kuenzli, Karri A; Buxton, Iain L O; Bradley, Michael E

    1998-01-01

    We evaluated the effect of the nitric oxide (NO) donor CysNO (S-nitroso-L-cysteine) and endogenous NO upon spontaneous contractility in non-pregnant cynomolgus monkeys. We also assessed the role of intracellular guanosine 3′,5′-cyclic monophosphate ([cyclic GMP]i) as a second messenger for NO in monkey uterine smooth muscle.CysNO reduced spontaneous contractility by 84% (P<0.05) at maximal concentrations, and significantly elevated [cyclic GMP]i (P<0.05). However, increases in [cyclic GMP]i were not required for CysNO-induced relaxations; CysNO inhibited contractile activity despite the complete inhibition of guanylyl cyclase by methylene blue or LY83,583.Analogues of cyclic GMP had no significant effect upon spontaneous contractile activity. L-arginine produced a 62% reduction in spontaneous activity (P<0.05) while D-arginine had no effect. The competitive nitric oxide synthase (NOS) inhibitor Nω-nitro-L-arginine (L-NOARG) not only blocked L-arginine-induced relaxations, but also significantly increased spontaneous contractile activity when added alone (P<0.05); the inactive D-enantiomer of NOARG had no such effect.While both endogenous NO and the NO donor CysNO relax monkey myometrium, this effect is not causally related to CysNO-induced elevations in [cyclic GMP]i. The failure of cyclic GMP analogues to alter monkey uterine smooth muscle tension also argues against a role for [cyclic GMP]i in the regulation of uterine contractility. Not only do these findings argue for the existence of a functionally-relevant NOS in the monkey uterus, but increases in contractile activity seen in the presence of NOS inhibitors suggest a role for NO in the moment-to-moment regulation of contractile activity in this organ. PMID:9630344

  20. Determinants of conditioned reinforcing effectiveness: Dopamine D2-like receptor agonist-stimulated responding for cocaine-associated stimuli.

    PubMed

    Collins, Gregory T; France, Charles P

    2015-12-15

    Environmental stimuli associated with drug use can take on conditioned properties capable of promoting drug-seeking behaviors during abstinence. This study investigated the relative importance of the amount of reinforced responding, number of cocaine-stimulus pairings, total cocaine intake, and reinforcing effectiveness of the self-administered dose of cocaine to the conditioned reinforcing effectiveness of cocaine-associated stimuli (CS). Male rats were trained to self-administer cocaine (0.1 [small] or 1.0mg/kg/inf [large]) under a fixed ratio schedule of reinforcement. A progressive ratio (PR) schedule was used to quantify the reinforcing effectiveness of each dose of cocaine, as well as the conditioned reinforcing effectiveness of the CS following treatment with saline or the dopamine D2-like receptor agonist pramipexole (0.1-3.2mg/kg). The large dose of cocaine maintained larger final ratios and greater levels of cocaine intake, whereas the small dose resulted in more cocaine-CS pairings. The total amount of responding was comparable between groups. During PR tests of conditioned reinforcement, pramipexole increased responding for CS presentations in both groups; however, the final ratio completed was significantly greater in large- as compared to small-dose group. In addition to highlighting a central role for dopamine D2-like receptors in modulating the effectiveness of cocaine-paired stimuli to reinforce behavior, these results suggest that conditioned reinforcing effectiveness is primarily determined by the reinforcing effectiveness of the self-administered dose of cocaine and/or total cocaine intake, and not the total amount of responding or number cocaine-stimulus pairings. These findings have implications for understanding how different patterns of drug-taking might impact vulnerability to relapse. PMID:26593427

  1. ACEA (a highly selective cannabinoid CB1 receptor agonist) stimulates hippocampal neurogenesis in mice treated with antiepileptic drugs.

    PubMed

    Andres-Mach, Marta; Haratym-Maj, Agnieszka; Zagaja, Miroslaw; Rola, Radoslaw; Maj, Maciej; Chrościńska-Krawczyk, Magdalena; Luszczki, Jarogniew J

    2015-10-22

    Hippocampal neurogenesis plays a very important role in learning and memory functions. In a search for best neurological drugs that protect neuronal cells and stimulate neurogenesis with no side effects, cannabinoids proved to be a strong group of substances having many beneficial properties. The aim of this study was to evaluate the impact of ACEA (arachidonyl-2'-chloroethylamide--a highly selective cannabinoid CB1 receptor agonist) combined with a classical antiepileptic drug sodium valproate (VPA) on neural precursor cells' proliferation and differentiation in the mouse brain. All experiments were performed on adolescent CB57/BL male mice injected i.p. with VPA (10mg/kg), ACEA (10mg/kg) and PMSF (30 mg/kg) (phenylmethylsulfonyl fluoride--a substance protecting ACEA against degradation by the fatty-acid amidohydrolase) for 10 days. Next an acute response of proliferating neural precursor cells to ACEA and VPA administration was evaluated with Ki-67 staining (Time point 1). Next, in order to determine whether acute changes translated into long-term alterations in neurogenesis, proliferating cells were labeled with 5-bromo-2deoxyuridine (BrdU) followed by confocal microscopy used to determine the percentage of BrdU-labeled cells that showed mature cell phenotypes (Time point 2). Results indicate that ACEA with PMSF significantly increase the total number of Ki-67-positive cells when compared to the control group. Moreover, ACEA in combination with VPA increased the number of Ki-67-positive cells, whereas VPA administered alone had no impact on proliferating cells' population. Accordingly, neurogenesis study results indicate that the combination of ACEA+PMSF administered alone and in combination with VPA considerably increases the total number of BrdU-positive cells in comparison to the control group while ACEA+PMSF alone and in combination with VPA increased total numbers of BrdU-positive cells, newly born neurons and astrocytes as compared to VPA group but not to the control group. VPA administered alone decreased the number of newly born neurons with no significant impact on neurogenesis. These data provide substantial evidence that VPA administered chronically slightly decreases the proliferation and differentiation of newly born cells while combination of VPA+ACEA significantly increases the level of newborn neurons in the dentate subgranular zone.

  2. Determinants of conditioned reinforcing effectiveness: Dopamine D2-like receptor agonist-stimulated responding for cocaine-associated stimuli.

    PubMed

    Collins, Gregory T; France, Charles P

    2015-12-15

    Environmental stimuli associated with drug use can take on conditioned properties capable of promoting drug-seeking behaviors during abstinence. This study investigated the relative importance of the amount of reinforced responding, number of cocaine-stimulus pairings, total cocaine intake, and reinforcing effectiveness of the self-administered dose of cocaine to the conditioned reinforcing effectiveness of cocaine-associated stimuli (CS). Male rats were trained to self-administer cocaine (0.1 [small] or 1.0mg/kg/inf [large]) under a fixed ratio schedule of reinforcement. A progressive ratio (PR) schedule was used to quantify the reinforcing effectiveness of each dose of cocaine, as well as the conditioned reinforcing effectiveness of the CS following treatment with saline or the dopamine D2-like receptor agonist pramipexole (0.1-3.2mg/kg). The large dose of cocaine maintained larger final ratios and greater levels of cocaine intake, whereas the small dose resulted in more cocaine-CS pairings. The total amount of responding was comparable between groups. During PR tests of conditioned reinforcement, pramipexole increased responding for CS presentations in both groups; however, the final ratio completed was significantly greater in large- as compared to small-dose group. In addition to highlighting a central role for dopamine D2-like receptors in modulating the effectiveness of cocaine-paired stimuli to reinforce behavior, these results suggest that conditioned reinforcing effectiveness is primarily determined by the reinforcing effectiveness of the self-administered dose of cocaine and/or total cocaine intake, and not the total amount of responding or number cocaine-stimulus pairings. These findings have implications for understanding how different patterns of drug-taking might impact vulnerability to relapse.

  3. A flagellin-derived toll-like receptor 5 agonist stimulates cytotoxic lymphocyte-mediated tumor immunity.

    PubMed

    Leigh, Nicholas D; Bian, Guanglin; Ding, Xilai; Liu, Hong; Aygun-Sunar, Semra; Burdelya, Lyudmila G; Gudkov, Andrei V; Cao, Xuefang

    2014-01-01

    Toll-like receptor (TLR) mediated recognition of pathogen associated molecular patterns allows the immune system to rapidly respond to a pathogenic insult. The "danger context" elicited by TLR agonists allows an initially non-immunogenic antigen to become immunogenic. This ability to alter environment is highly relevant in tumor immunity, since it is inherently difficult for the immune system to recognize host-derived tumors as immunogenic. However, immune cells may have encountered certain TLR ligands associated with tumor development, yet the endogenous stimulation is typically not sufficient to induce spontaneous tumor rejection. Of special interest are TLR5 agonists, because there are no endogenous ligands that bind TLR5. CBLB502 is a pharmacologically optimized TLR5 agonist derived from Salmonella enterica flagellin. We examined the effect of CBLB502 on tumor immunity using two syngeneic lymphoma models, both of which do not express TLR5, and thus do not directly respond to CBLB502. Upon challenge with the T-cell lymphoma RMAS, CBLB502 treatment after tumor inoculation protects C57BL/6 mice from death caused by tumor growth. This protective effect is both natural killer (NK) cell- and perforin-dependent. In addition, CBLB502 stimulates clearance of the B-cell lymphoma A20 in BALB/c mice in a CD8(+) T cell-dependent fashion. Analysis on the cellular level via ImageStream flow cytometry reveals that CD11b(+) and CD11c(+) cells, but neither NK nor T cells, directly respond to CBLB502 as determined by NFκB nuclear translocation. Our findings demonstrate that CBLB502 stimulates a robust antitumor response by directly activating TLR5-expressing accessory immune cells, which in turn activate cytotoxic lymphocytes.

  4. Novel Small Molecule Glucagon-Like Peptide-1 Receptor Agonist Stimulates Insulin Secretion in Rodents and From Human Islets

    PubMed Central

    Sloop, Kyle W.; Willard, Francis S.; Brenner, Martin B.; Ficorilli, James; Valasek, Kathleen; Showalter, Aaron D.; Farb, Thomas B.; Cao, Julia X.C.; Cox, Amy L.; Michael, M. Dodson; Gutierrez Sanfeliciano, Sonia Maria; Tebbe, Mark J.; Coghlan, Michael J.

    2010-01-01

    OBJECTIVE The clinical effectiveness of parenterally-administered glucagon-like peptide-1 (GLP-1) mimetics to improve glucose control in patients suffering from type 2 diabetes strongly supports discovery pursuits aimed at identifying and developing orally active, small molecule GLP-1 receptor agonists. The purpose of these studies was to identify and characterize novel nonpeptide agonists of the GLP-1 receptor. RESEARCH DESIGN AND METHODS Screening using cells expressing the GLP-1 receptor and insulin secretion assays with rodent and human islets were used to identify novel molecules. The intravenous glucose tolerance test (IVGTT) and hyperglycemic clamp characterized the insulinotropic effects of compounds in vivo. RESULTS Novel low molecular weight pyrimidine-based compounds that activate the GLP-1 receptor and stimulate glucose-dependent insulin secretion are described. These molecules induce GLP-1 receptor-mediated cAMP signaling in HEK293 cells expressing the GLP-1 receptor and increase insulin secretion from rodent islets in a dose-dependent manner. The compounds activate GLP-1 receptor signaling, both alone or in an additive fashion when combined with the endogenous GLP-1 peptide; however, these agonists do not compete with radiolabeled GLP-1 in receptor-binding assays. In vivo studies using the IVGTT and the hyperglycemic clamp in Sprague Dawley rats demonstrate increased insulin secretion in compound-treated animals. Further, perifusion assays with human islets isolated from a donor with type 2 diabetes show near-normalization of insulin secretion upon compound treatment. CONCLUSIONS These studies characterize the insulinotropic effects of an early-stage, small molecule GLP-1 receptor agonist and provide compelling evidence to support pharmaceutical optimization. PMID:20823098

  5. Modulation of NMDA effects on agonist-stimulated phosphoinositide turnover by memantine in neonatal rat cerebral cortex.

    PubMed Central

    Mistry, R; Wilke, R; Challiss, R A

    1995-01-01

    1. The ability of memantine (1-amino-3,5-dimethyladamantane) to antagonize the modulatory effects of N-methyl-D-aspartate (NMDA) on phosphoinositide turnover stimulated by muscarinic cholinoceptor- and metabotropic glutamate receptor-agonists has been examined in neonatal rat cerebral cortex slices. 2. Memantine antagonized the inhibitory effect of NMDA (100 microM) on both total [3H]-inositol phosphate ([3H]-InsPx) and inositol 1,4,5-trisphosphate (Ins(1,4,5)P3) mass accumulations stimulated by carbachol (1 mM) with EC50 values of 21 and 16 microM respectively. 3. Memantine concentration-dependently antagonized (IC50 24 microM) the ability of NMDA (10 microM) to potentiate [3H]-InsPx accumulation in response to a sub-maximal concentration of the metabotropic glutamate receptor agonist, 1S,3R-ACPD (10 microM). 4. The small (approx. 3 fold), concentration-dependent increase in [3H]-InsPx accumulation stimulated by NMDA was completely antagonized by the prototypic NDMA receptor-channel blocker, MK-801 (1 microM) at all concentrations of NDMA studied (1-1000 microM). In contrast, antagonism by memantine (100 microM) was observed only at low concentrations of NMDA (1-10 microM), whilst [3H]-InsPx accumulation stimulated by high concentrations of NMDA (300-1000 microM) was markedly enhanced by memantine. 5. Assessment of the incorporation of [3H]-inositol into inositol phospholipids revealed that memantine (100 microM) caused an approximate 2 fold increase in the labelling of phosphatidylinositol, phosphatidylinositol 4-phosphate and phosphatidylinositol 4,5-bisphosphate.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:7773540

  6. Increasing extracellular H2O2 produces a bi-phasic response in intracellular H2O2, with peroxiredoxin hyperoxidation only triggered once the cellular H2O2-buffering capacity is overwhelmed.

    PubMed

    Tomalin, Lewis Elwood; Day, Alison Michelle; Underwood, Zoe Elizabeth; Smith, Graham Robert; Dalle Pezze, Piero; Rallis, Charalampos; Patel, Waseema; Dickinson, Bryan Craig; Bähler, Jürg; Brewer, Thomas Francis; Chang, Christopher Joh-Leung; Shanley, Daryl Pierson; Veal, Elizabeth Ann

    2016-06-01

    Reactive oxygen species, such as H2O2, can damage cells but also promote fundamental processes, including growth, differentiation and migration. The mechanisms allowing cells to differentially respond to toxic or signaling H2O2 levels are poorly defined. Here we reveal that increasing external H2O2 produces a bi-phasic response in intracellular H2O2. Peroxiredoxins (Prx) are abundant peroxidases which protect against genome instability, ageing and cancer. We have developed a dynamic model simulating in vivo changes in Prx oxidation. Remarkably, we show that the thioredoxin peroxidase activity of Prx does not provide any significant protection against external rises in H2O2. Instead, our model and experimental data are consistent with low levels of extracellular H2O2 being efficiently buffered by other thioredoxin-dependent activities, including H2O2-reactive cysteines in the thiol-proteome. We show that when extracellular H2O2 levels overwhelm this buffering capacity, the consequent rise in intracellular H2O2 triggers hyperoxidation of Prx to thioredoxin-resistant, peroxidase-inactive form/s. Accordingly, Prx hyperoxidation signals that H2O2 defenses are breached, diverting thioredoxin to repair damage. PMID:26944189

  7. Increasing extracellular H2O2 produces a bi-phasic response in intracellular H2O2, with peroxiredoxin hyperoxidation only triggered once the cellular H2O2-buffering capacity is overwhelmed.

    PubMed

    Tomalin, Lewis Elwood; Day, Alison Michelle; Underwood, Zoe Elizabeth; Smith, Graham Robert; Dalle Pezze, Piero; Rallis, Charalampos; Patel, Waseema; Dickinson, Bryan Craig; Bähler, Jürg; Brewer, Thomas Francis; Chang, Christopher Joh-Leung; Shanley, Daryl Pierson; Veal, Elizabeth Ann

    2016-06-01

    Reactive oxygen species, such as H2O2, can damage cells but also promote fundamental processes, including growth, differentiation and migration. The mechanisms allowing cells to differentially respond to toxic or signaling H2O2 levels are poorly defined. Here we reveal that increasing external H2O2 produces a bi-phasic response in intracellular H2O2. Peroxiredoxins (Prx) are abundant peroxidases which protect against genome instability, ageing and cancer. We have developed a dynamic model simulating in vivo changes in Prx oxidation. Remarkably, we show that the thioredoxin peroxidase activity of Prx does not provide any significant protection against external rises in H2O2. Instead, our model and experimental data are consistent with low levels of extracellular H2O2 being efficiently buffered by other thioredoxin-dependent activities, including H2O2-reactive cysteines in the thiol-proteome. We show that when extracellular H2O2 levels overwhelm this buffering capacity, the consequent rise in intracellular H2O2 triggers hyperoxidation of Prx to thioredoxin-resistant, peroxidase-inactive form/s. Accordingly, Prx hyperoxidation signals that H2O2 defenses are breached, diverting thioredoxin to repair damage.

  8. Gene expression analyses of immune responses in Atlantic salmon during early stages of infection by salmon louse (Lepeophtheirus salmonis) revealed bi-phasic responses coinciding with the copepod-chalimus transition

    PubMed Central

    2011-01-01

    Background The salmon louse (Lepeophtheirus salmonis Krøyer), an ectoparasitic copepod with a complex life cycle causes significant losses in salmon aquaculture. Pesticide treatments against the parasite raise environmental concerns and their efficacy is gradually decreasing. Improvement of fish resistance to lice, through biological control methods, needs better understanding of the protective mechanisms. We used a 21 k oligonucleotide microarray and RT-qPCR to examine the time-course of immune gene expression changes in salmon skin, spleen, and head kidney during the first 15 days after challenge, which encompassed the copepod and chalimus stages of lice development. Results Large scale and highly complex transcriptome responses were found already one day after infection (dpi). Many genes showed bi-phasic expression profiles with abrupt changes between 5 and 10 dpi (the copepod-chalimus transitions); the greatest fluctuations (up- and down-regulation) were seen in a large group of secretory splenic proteases with unknown roles. Rapid sensing was witnessed with induction of genes involved in innate immunity including lectins and enzymes of eicosanoid metabolism in skin and acute phase proteins in spleen. Transient (1-5 dpi) increase of T-cell receptor alpha, CD4-1, and possible regulators of lymphocyte differentiation suggested recruitment of T-cells of unidentified lineage to the skin. After 5 dpi the magnitude of transcriptomic responses decreased markedly in skin. Up-regulation of matrix metalloproteinases in all studied organs suggested establishment of a chronic inflammatory status. Up-regulation of putative lymphocyte G0/G1 switch proteins in spleen at 5 dpi, immunoglobulins at 15 dpi; and increase of IgM and IgT transcripts in skin indicated an onset of adaptive humoral immune responses, whereas MHCI appeared to be down-regulated. Conclusions Atlantic salmon develops rapid local and systemic reactions to L. salmonis, which, however, do not result in

  9. Phasic Affective Modulation of Semantic Priming

    ERIC Educational Resources Information Center

    Topolinski, Sascha; Deutsch, Roland

    2013-01-01

    The present research demonstrates that very brief variations in affect, being around 1 s in length and changing from trial to trial independently from semantic relatedness of primes and targets, modulate the amount of semantic priming. Implementing consonant and dissonant chords (Experiments 1 and 5), naturalistic sounds (Experiment 2), and visual…

  10. Diminished agonist-stimulated inositol trisphosphate generation blocks stimulus-secretion coupling in mouse pancreatic acini during diet-induced experimental pancreatitis

    SciTech Connect

    Powers, R.E.; Saluja, A.K.; Houlihan, M.J.; Steer, M.L.

    1986-05-01

    Young female mice fed a choline-deficient, ethionine-supplemented (CDE) diet rapidly develop acute hemorrhagic pancreatitis. We have observed that pancreatic acini prepared from these mice are unable to secrete amylase in response to addition of the cholinergic agonist carbachol, although they retain the ability to secrete amylase in response to the Ca2+ ionophore A23187. The CDE diet does not alter the binding characteristics (Kd or the maximal number of binding sites) for muscarinic cholinergic receptors as tested using the antagonist (/sup 3/H)N-methylscopolamine nor the competition for this binding by carbachol. Addition of carbachol to acini prepared from mice fed the CDE diet does not result in as marked an increase in cytosolic free Ca2+ levels as that noted in control samples (evaluated using quin2 fluorescence). These observations indicate that the CDE diet interferes with stimulus-secretion coupling in mouse pancreatic acini at a step subsequent to hormone-receptor binding and prior to Ca2+ release. This conclusion is confirmed by our finding that the hormone-stimulated generation of (/sup 3/H)inositol phosphates (inositol trisphosphate, inositol bisphosphate, and inositol monophosphate) from acini labeled with (/sup 3/H)myoinositol is markedly reduced in acini prepared from mice fed the CDE diet. This reduction is not due to a decrease in phosphatidylinositol-4,5-bisphosphate. This communication represents the first report of a system in which a blockade of inositol phosphate generation can be related to a physiologic defect and pathologic lesion.

  11. Hydrogen sulfide decreases β-adrenergic agonist-stimulated lung liquid clearance by inhibiting ENaC-mediated transepithelial sodium absorption

    PubMed Central

    Agné, Alisa M.; Baldin, Jan-Peter; Benjamin, Audra R.; Orogo-Wenn, Maria C.; Wichmann, Lukas; Olson, Kenneth R.; Walters, Dafydd V.

    2015-01-01

    In pulmonary epithelia, β-adrenergic agonists regulate the membrane abundance of the epithelial sodium channel (ENaC) and, thereby, control the rate of transepithelial electrolyte absorption. This is a crucial regulatory mechanism for lung liquid clearance at birth and thereafter. This study investigated the influence of the gaseous signaling molecule hydrogen sulfide (H2S) on β-adrenergic agonist-regulated pulmonary sodium and liquid absorption. Application of the H2S-liberating molecule Na2S (50 μM) to the alveolar compartment of rat lungs in situ decreased baseline liquid absorption and abrogated the stimulation of liquid absorption by the β-adrenergic agonist terbutaline. There was no additional effect of Na2S over that of the ENaC inhibitor amiloride. In electrophysiological Ussing chamber experiments with native lung epithelia (Xenopus laevis), Na2S inhibited the stimulation of amiloride-sensitive current by terbutaline. β-adrenergic agonists generally increase ENaC abundance by cAMP formation and activation of PKA. Activation of this pathway by forskolin and 3-isobutyl-1-methylxanthine increased amiloride-sensitive currents in H441 pulmonary epithelial cells. This effect was inhibited by Na2S in a dose-dependent manner (5–50 μM). Na2S had no effect on cellular ATP concentration, cAMP formation, and activation of PKA. By contrast, Na2S prevented the cAMP-induced increase in ENaC activity in the apical membrane of H441 cells. H441 cells expressed the H2S-generating enzymes cystathionine-β-synthase, cystathionine-γ-lyase, and 3-mercaptopyruvate sulfurtransferase, and they produced H2S amounts within the employed concentration range. These data demonstrate that H2S prevents the stimulation of ENaC by cAMP/PKA and, thereby, inhibits the proabsorptive effect of β-adrenergic agonists on lung liquid clearance. PMID:25632025

  12. Visualization of distinct patterns of subcellular redistribution of the thyrotropin-releasing hormone receptor-1 and gqalpha /G11alpha induced by agonist stimulation.

    PubMed Central

    Drmota, T; Novotny, J; Gould, G W; Svoboda, P; Milligan, G

    1999-01-01

    The rat thyrotropin-releasing hormone receptor-1 (TRHR-1) was modified by the addition of green fluorescent protein (GFP) and expressed stably in HEK293 cells. Extensive overlap of plasma membrane distribution of autofluorescent TRHR-1-GFP with that of the phosphoinositidase C-linked G-proteins Gqalpha/G11alpha, identified by indirect immunofluorescence, was monitored concurrently. Addition of thyrotropin-releasing hormone resulted in rapid separation of TRHR-1-GFP and Gqalpha/G11alpha signals as the receptor was internalized. This situation persisted for more than an hour. At longer time periods a fraction of the cellular Gqalpha/G11alpha was also internalized, although much of the Gqalpha/G11alpha immunoreactivity remained associated with the plasma membrane. Parallel experiments, in which the cellular distribution of TRHR-1-GFP and Gqalpha/G11alpha immunoreactivity were monitored in sucrose-gradient fractions following cell disruption, also demonstrated a rapid, agonist-induced movement of TRHR-1-GFP away from the plasma membrane to low-density vesicular fractions. At later time points, a fraction of the cellular Gqalpha/G11alpha immunoreactivity was also redistributed to overlapping, but non-identical, low-density-vesicle-containing fractions. Pretreatment of the cells with cytochalasin D or nocodazole prevented agonist-induced redistribution of G-protein but not TRHR-1-GFP, further indicating resolution of the mechanics of these two processes. The combination of a GFP-modified receptor and immunostaining of the G-proteins activated by that receptor allows, for the first time, concurrent analysis of the varying dynamics and bases of internalization and redistribution of two elements of the same signal-transduction cascade. PMID:10333499

  13. Hydrogen sulfide decreases β-adrenergic agonist-stimulated lung liquid clearance by inhibiting ENaC-mediated transepithelial sodium absorption.

    PubMed

    Agné, Alisa M; Baldin, Jan-Peter; Benjamin, Audra R; Orogo-Wenn, Maria C; Wichmann, Lukas; Olson, Kenneth R; Walters, Dafydd V; Althaus, Mike

    2015-04-01

    In pulmonary epithelia, β-adrenergic agonists regulate the membrane abundance of the epithelial sodium channel (ENaC) and, thereby, control the rate of transepithelial electrolyte absorption. This is a crucial regulatory mechanism for lung liquid clearance at birth and thereafter. This study investigated the influence of the gaseous signaling molecule hydrogen sulfide (H2S) on β-adrenergic agonist-regulated pulmonary sodium and liquid absorption. Application of the H2S-liberating molecule Na2S (50 μM) to the alveolar compartment of rat lungs in situ decreased baseline liquid absorption and abrogated the stimulation of liquid absorption by the β-adrenergic agonist terbutaline. There was no additional effect of Na2S over that of the ENaC inhibitor amiloride. In electrophysiological Ussing chamber experiments with native lung epithelia (Xenopus laevis), Na2S inhibited the stimulation of amiloride-sensitive current by terbutaline. β-adrenergic agonists generally increase ENaC abundance by cAMP formation and activation of PKA. Activation of this pathway by forskolin and 3-isobutyl-1-methylxanthine increased amiloride-sensitive currents in H441 pulmonary epithelial cells. This effect was inhibited by Na2S in a dose-dependent manner (5-50 μM). Na2S had no effect on cellular ATP concentration, cAMP formation, and activation of PKA. By contrast, Na2S prevented the cAMP-induced increase in ENaC activity in the apical membrane of H441 cells. H441 cells expressed the H2S-generating enzymes cystathionine-β-synthase, cystathionine-γ-lyase, and 3-mercaptopyruvate sulfurtransferase, and they produced H2S amounts within the employed concentration range. These data demonstrate that H2S prevents the stimulation of ENaC by cAMP/PKA and, thereby, inhibits the proabsorptive effect of β-adrenergic agonists on lung liquid clearance.

  14. Early and Phasic Cortical Metabolic Changes in Vestibular Neuritis Onset

    PubMed Central

    Alessandrini, Marco; Pagani, Marco; Napolitano, Bianca; Micarelli, Alessandro; Candidi, Matteo; Bruno, Ernesto; Chiaravalloti, Agostino; Di Pietro, Barbara; Schillaci, Orazio

    2013-01-01

    Functional brain activation studies described the presence of separate cortical areas responsible for central processing of peripheral vestibular information and reported their activation and interactions with other sensory modalities and the changes of this network associated to strategic peripheral or central vestibular lesions. It is already known that cortical changes induced by acute unilateral vestibular failure (UVF) are various and undergo variations over time, revealing different cortical involved areas at the onset and recovery from symptoms. The present study aimed at reporting the earliest change in cortical metabolic activity during a paradigmatic form of UVF such as vestibular neuritis (VN), that is, a purely peripheral lesion of the vestibular system, that offers the opportunity to study the cortical response to altered vestibular processing. This research reports [18F]fluorodeoxyglucose positron emission tomography brain scan data concerning the early cortical metabolic activity associated to symptoms onset in a group of eight patients suffering from VN. VN patients’ cortical metabolic activity during the first two days from symptoms onset was compared to that recorded one month later and to a control healthy group. Beside the known cortical response in the sensorimotor network associated to vestibular deafferentation, we show for the first time the involvement of Entorhinal (BAs 28, 34) and Temporal (BA 38) cortices in early phases of symptomatology onset. We interpret these findings as the cortical counterparts of the attempt to reorient oneself in space counteracting the vertigo symptom (Bas 28, 34) and of the emotional response to the new pathologic condition (BA 38) respectively. These interpretations were further supported by changes in patients’ subjective ratings in balance, anxiety, and depersonalization/derealization scores when tested at illness onset and one month later. The present findings contribute in expanding knowledge about early, fast-changing, and complex cortical responses to pathological vestibular unbalanced processing. PMID:23505435

  15. Relationship between ultrasonically detected phasic antral contractions and antral pressure.

    PubMed

    Hveem, K; Sun, W M; Hebbard, G; Horowitz, M; Doran, S; Dent, J

    2001-07-01

    The relationships between gastric wall motion and intraluminal pressure are believed to be major determinants of flows within and from the stomach. Gastric antral wall motion and intraluminal pressures were monitored in five healthy subjects by concurrent antropyloroduodenal manometry and transabdominal ultrasound for 60 min after subjects drank 500 ml of clear soup. We found that 99% of antral contractions detected by ultrasound were propagated aborally, and 68% of contractions became lumen occlusive at the site of the ultrasound marker. Of the 203 contractions detected by ultrasound, 53% were associated with pressure events in the manometric reference channel; 86% of contractions had corresponding pressure events detectable somewhere in the antrum. Contractions that occluded the lumen were more likely to be associated with a pressure event in the manometric reference channel (P < 0.01) and to be of greater amplitude (P < 0.01) than non-lumen-occlusive contractions. We conclude that heterogeneous pressure event patterns in the antrum occur despite a stereotyped pattern of contraction propagation seen on ultrasound. Lumen occlusion is more likely to be associated with higher peak antral pressure events.

  16. Optical suppression of drug-evoked phasic dopamine release.

    PubMed

    McCutcheon, James E; Cone, Jackson J; Sinon, Christopher G; Fortin, Samantha M; Kantak, Pranish A; Witten, Ilana B; Deisseroth, Karl; Stuber, Garret D; Roitman, Mitchell F

    2014-01-01

    Brief fluctuations in dopamine concentration (dopamine transients) play a key role in behavior towards rewards, including drugs of abuse. Drug-evoked dopamine transients may result from actions at both dopamine cell bodies and dopamine terminals. Inhibitory opsins can be targeted to dopamine neurons permitting their firing activity to be suppressed. However, as dopamine transients can become uncoupled from firing, it is unknown whether optogenetic hyperpolarization at the level of the soma is able to suppress dopamine transients. Here, we used in vivo fast-scan cyclic voltammetry to record transients evoked by cocaine and raclopride in nucleus accumbens (NAc) of urethane-anesthetized rats. We targeted halorhodopsin (NpHR) specifically to dopamine cells by injecting Cre-inducible virus into ventral tegmental area (VTA) of transgenic rats that expressed Cre recombinase under control of the tyrosine hydroxylase promoter (TH-Cre(+) rats). Consistent with previous work, co-administration of cocaine and raclopride led to the generation of dopamine transients in NAc shell. Illumination of VTA with laser strongly suppressed the frequency of transients in NpHR-expressing rats, but not in control rats. Laser did not have any effect on amplitude of transients. Thus, optogenetics can effectively reduce the occurrence of drug-evoked transients and is therefore a suitable approach for studying the functional role of such transients in drug-associated behavior.

  17. [Methods for quantifying phasic skin conductance amplitudes: threats to validity?].

    PubMed

    Zimmer, H; Vossel, G

    1993-01-01

    Two methods of determining the event-related skin conductance response (SCR) amplitude are in common use. In one of these, the difference in conductance between the point of onset and the peak level of a single wave is measured (method 1). The second approach is to determine the difference between two measures, one characterizing the prestimulus level, the other the highest conductance point of the SCR reached within a fixed period following the stimulus (method 2). A problem with quantifying the SCR amplitude occurs when a SCR is elicited before an immediately preceding response has had time to recover, because in this case the two methods lead to quite different values. If the amplitude of each response is measured from its own individual deflection point, the measurable amplitude of the second response will be smaller when it occurs immediately after or in the ascending limb of the first response. The problem is most evident in situations with a high probability of response superimposition, such as when a large number of nonspecific responses occur at the same time as the SCRs. This is found in individuals with a high degree of electrodermal lability. Electrodermal lability refers to a psychophysiological construct that is operationally defined by the frequency of spontaneous electrodermal fluctuations. In the present study, we therefore systematically investigated the effects of the two score methods on SCR amplitude in relation to lability by analyzing electrodermal data from two habituation studies. As expected, several method-specific effects which were related to lability emerged. Results and questions concerning the relevance of the findings are discussed, with special emphasis on the validity of psychophysiological investigations.

  18. Phasic heart rate changes during word translation of different difficulties.

    PubMed

    Pfurtscheller, Gert; Grabner, Roland H; Brunner, Clemens; Neuper, Christa

    2007-09-01

    The heart rate (HR) can be modulated by diverse mental activities ranging from stimulus anticipation to higher order cognitive information processing. In the present study we report on HR changes during word translation and examine how the HR is influenced by the difficulty of the translation task. Twelve students of translation and interpreting were presented English high- and low-frequency words as well as familiar and unfamiliar technical terms that had to be translated into German. Analyses revealed that words of higher translation difficulty were accompanied by a more pronounced HR deceleration than words that were easier to translate. We additionally show that anticipatory HR deceleration and HR changes induced by motor preparation and activity due to typing the translation do not depend on task difficulty. These results provide first evidence of a link between task difficulty in language translation and event-related HR changes. PMID:17608800

  19. Gene deletion of KLF9 in mice results in aberrant endometrial proliferation and myometrial function

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Timely regulation of uterine function is critical for successful pregnancy. Our laboratory has previously identified Basic transcription element binding protein-1/Krüppel-like factor 9 (Bteb1/Klf9), a member of Sp/KLF family of transcription factor, as a progesterone receptor (Pgr) interacting prote...

  20. Characterization of the myometrial transcriptome and biological pathways of spontaneous human labor at term

    PubMed Central

    Mittal, Pooja; Romero, Roberto; Tarca, Adi L.; Gonzalez, Juan; Draghici, Sorin; Xu, Yi; Dong, Zhong; Nhan-Chang, Chia-Ling; Chaiworapongsa, Tinnakorn; Lye, Stephen; Kusanovic, Juan Pedro; Lipovich, Leonard; Mazaki-Tovi, Shali; Hassan, Sonia S.; Mesiano, Sam; Kim, Chong Jai

    2011-01-01

    Aims To characterize the transcriptome of human myometrium during spontaneous labor at term. Methods Myometrium was obtained from women with (n=19) and without labor (n=20). Illumina® HumanHT-12 microarrays were utilized. Moderated t-tests and False Discovery Rate adjustment of p-values were applied. qRT-PCR was performed for a select set of differentially expressed genes in a separate set of samples. ELISA and Western Blot were utilized to confirm differential protein production in a third sample set. Results 1) 471 genes were differentially expressed; 2) Gene Ontology analysis indicated enrichment of 103 biological processes and 18 molecular functions including: a) inflammatory response; b) cytokine activity; and c) chemokine activity; 3) systems biology pathway analysis using Signaling Pathway Impact Analysis indicated 6 significant pathways: a) cytokine-cytokine receptor interaction; b) Jak-Stat signaling; and c) complement and coagulation cascades; d) NOD-like receptor signaling pathway; e) Systemic Lupus Erythematosus; and f) Chemokine signaling pathway; 3) qRT-PCR confirmed over-expression of prostaglandin-endoperoxide synthase-2 (PTGS2/COX2), heparin binding EGF-like growth factor (HBEGF), chemokine C-C motif ligand 2 (CCL2/MCP1), leukocyte immunoglobulin-like receptor, subfamily A member 5 (LILRA5/LIR9), IL-8, IL-6, chemokine C-X-C motif ligand 6 (CXCL6/GCP2), nuclear factor of kappa light chain gene enhancer in B-cells inhibitor zeta (NFKBIZ), suppressor of cytokine signaling 3 (SOCS3) and decreased expression of FK506 binding-protein 5 (FKBP5) and aldehyde dehydrogenase (ALDH2) in labor; 4) IL-6, CXCL6, CCL2 and SOCS3 protein expression was significantly higher in the term labor group compared to the term not in labor group. Conclusions Myometrium of women in spontaneous labor at term is characterized by a stereotypic gene expression pattern consistent with over-expression of the inflammatory response and leukocyte chemotaxis. Differential gene expression identified with microarray was confirmed with qRT-PCR using an independent set of samples. This study represents an unbiased description of the biological processes involved in spontaneous labor at term based on transcriptomics. PMID:20629487

  1. Regulation of myometrial circulation and uterine vascular tone by constitutive nitric oxide.

    PubMed

    Toda, Noboru; Toda, Hiroshi; Okamura, Tomio

    2013-08-15

    Pregnancy is a physiological state that involves an increase in uterine blood flow, which is mediated in part by nitric oxide (NO) liberated from the endothelium and nitrergic neurons. The main focus of this review article is to provide information about how endogenous NO regulates uterine and placental blood flow and vascular tone in experimental animals and humans in vivo or in vitro in non-pregnant and pregnant states as well as pregnancy with pre-eclampsia. Uterine arteries from non-pregnant women respond to NO liberated from the endothelium and nitrergic nerves with relaxations, and the release of endothelial NO is influenced by the phase of the estrous cycle, with its enhanced release at the follicular phase when the estrogen level is high. NO bioavailability in the uteroplacental circulatory system is gradually increased during pregnancy. Pre-eclamptic pregnancies with or without intrauterine growth restriction show impaired uteroplacental blood flow accompanied by reduced NO synthesis due to down-regulation of eNOS as well as asymmetric dimethylarginine accumulation and by augmented NO degradation by oxidative stress. Further studies are expected to provide new mechanistic insights into the fascinating process of maternal uterine adaptation in humans and novel prophylactic and therapeutic measures against pre-eclampsia.

  2. Mouse osteoblastic cell line (MC3T3-E1) expresses extracellular calcium (Ca2+o)-sensing receptor and its agonists stimulate chemotaxis and proliferation of MC3T3-E1 cells

    NASA Technical Reports Server (NTRS)

    Yamaguchi, T.; Chattopadhyay, N.; Kifor, O.; Butters, R. R. Jr; Sugimoto, T.; Brown, E. M.; O'Malley, B. W. (Principal Investigator)

    1998-01-01

    The calcium-sensing receptor (CaR) is a G protein-coupled receptor that plays key roles in extracellular calcium ion (Ca2+o) homeostasis in parathyroid gland and kidney. Osteoblasts appear at sites of osteoclastic bone resorption during bone remodeling in the "reversal" phase following osteoclastic resorption and preceding bone formation. Bone resorption produces substantial local increases in Ca2+o that could provide a signal for osteoblasts in the vicinity, leading us to determine whether such osteoblasts express the CaR. In this study, we used the mouse osteoblastic, clonal cell line MC3T3-E1. Both immunocytochemistry and Western blot analysis, using an antiserum specific for the CaR, detected CaR protein in MC3T3-E1 cells. We also identified CaR transcripts in MC3T3-E1 cells by Northern analysis using a CaR-specific riboprobe and by reverse transcription-polymerase chain reaction with CaR-specific primers, followed by nucleotide sequencing of the amplified products. Exposure of MC3T3-E1 cells to high Ca2+o (up to 4.8 mM) or the polycationic CaR agonists, neomycin and gadolinium (Gd3+), stimulated both chemotaxis and DNA synthesis in MC3T3-E1 cells. Therefore, taken together, our data strongly suggest that the osteoblastic cell line MC3T3-E1 possesses both CaR protein and mRNA very similar, if not identical, to those in parathyroid and kidney. Furthermore, the CaR in these osteoblasts could play a key role in regulating bone turnover by stimulating the proliferation and migration of such cells to sites of bone resorption as a result of local release of Ca2+o.

  3. Cannabinoid agonists stimulate [3H]GABA release in the globus pallidus of the rat when G(i) protein-receptor coupling is restricted: role of dopamine D2 receptors.

    PubMed

    Gonzalez, Brenda; Paz, Francisco; Florán, Leonor; Aceves, Jorge; Erlij, David; Florán, Benjamín

    2009-03-01

    The motor effects of cannabinoids in the globus pallidus appear to be caused by increases in interstitial GABA. To elucidate the mechanism of this response, we investigated the effect of the selective cannabinoid type 1 receptor (CB1) cannabinoid agonist arachidonyl-2-chloroethylamide (ACEA) on [(3)H]GABA release in slices of the rat globus pallidus. ACEA had two effects: concentrations between 10(-8) and 10(-6) M stimulated release, whereas higher concentrations (IC(50) approximately 10(-6) M) inhibited it. Another cannabinoid agonist, WIN-55,212-2, also had bimodal effects on release. Studies of cAMP production indicate that under conditions of low G(i/o), availability the coupling of CB1 receptors with G(i/o) proteins can be changed into CB1:G(s/olf) coupling; therefore, we determined the effects of conditions that limit G(i/o) availability on [(3)H]GABA release. Blockers of G(i/o) protein interactions, pertussis toxin and N-ethylmaleimide, transformed the inhibitory effects of ACEA on GABA release into stimulation. It also has been suggested that stimulation of D2 receptors can reduce G(i/o) availability. Blocking D2 receptors with sulpiride [(S)-5-aminosulfonyl-N-[(1-ethyl-2-pyrrolidinyl)methyl]-2-methoxybenzamidersqb] or depleting dopamine with reserpine inhibited the ACEA-induced stimulation of release. Thus, the D2 dependence of stimulation is consistent with the proposal that D2 receptors reduce G(i/o) proteins available for binding to the CB1 receptor. In summary, CB1 receptor activation has dual effects on GABA release in the globus pallidus. Low concentrations stimulate release through a process that depends on activation of dopamine D2 receptors that may limit G(i/o) protein availability. Higher concentrations of cannabinoid inhibit GABA release through mechanisms that are independent of D2 receptor activation.

  4. Effects of combined progesterone and 17β-estradiol treatment on the transcriptome of cultured human myometrial smooth muscle cells.

    PubMed

    Chandran, Sreenath; Cairns, Michael T; O'Brien, Margaret; O'Connell, Enda; Mashayekhi, Kaveh; Smith, Terry J

    2016-01-01

    A transcriptomic analysis of cultured human uterine smooth muscle cells (hUtSMCs) was performed to examine gene expression profiles in smooth muscle in an environment containing the two major steroid hormones that regulate the human myometrium in physiological states associated with estrous, pregnancy, labor, and pathophysiological states such as leiomyoma and endometrial cancer. hUtSMCs were treated with progesterone (P4) and 17β-estradiol (E2) individually and in combination, in the presence and absence of RU486 (mifepristone). Transcription of many genes was modulated in the presence of P4 or E2 alone, but almost six times more genes were transcriptionally modulated in the presence of the P4/E2 hormone combination. In total 796 annotated genes were significantly differentially expressed in the presence of both P4 and E2 relative to their expression in untreated cells. Functional withdrawal of P4 by addition of RU486 effectively reversed almost all transcriptional changes caused by P4/E2 treatment. Gene ontology analysis of differentially expressed genes revealed a strong association between P4/E2 treatment and downregulated expression of genes involved in cell communication, signal transduction, channel activity, inflammatory response, and differentiation. Upregulated processes included cell survival, gene transcription, steroid hormone biosynthesis, muscle development, insulin receptor signaling, and cell growth.

  5. Myometrial Wound Healing Post-Cesarean Delivery in the MRL/MpJ Mouse Model of Uterine Scarring

    PubMed Central

    Buhimschi, Catalin S.; Zhao, Guomao; Sora, Nicoleta; Madri, Joseph A.; Buhimschi, Irina A.

    2010-01-01

    There is little known about healing of the uterus after Cesarean delivery (CD). Uterine wound repair was studied by using two strains of mice with different wound healing characteristics: MRL/MpJ+/+ (MRL: “high-healer” phenotype) and C57Bl/6 (“low-healer” phenotype). First, we examined the morphology and histology of the uterine wall repair. We identified wound granulation tissue 3 days post-CD in both strains, albeit less in the MRL strain. Macroscopically, no scar could be identified either in MRL or C57Bl/6 mice on day 60 post-CD. However, histologically, we found significant differences in wound integration, inflammation, and collagen birefringence between the two strains of mice. Using a histological index, we provided evidence for significant differences in mitotic activity in the initial phases of uterine healing among strains. Functional behavior of the uterine scar also was analyzed by using biomechanical parameters such as slope (measure of stiffness), yield point (measure of elasticity), and break point (measure of strength). There were significant differences in stiffness of the scarred myometrium between the two phenotypes. MRL mice displayed a significantly lower yield point compared with C57Bl/6. The break point was reached faster on days 15 and 60 in both C57Bl/6 and MRL strains compared with day 3 post-CD. Our findings indicate that differences in regenerative ability translate in histological, mitotic, and functional differences in biomechanical properties of the scarred myometrium after CD. PMID:20489145

  6. Delayed Parturition and Altered Myometrial Progesterone Receptor Isoform A Expression in Mice Null for Kruppel-like Factor 9

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Pre-term and delayed labor conditions are devastating health problems, with currently unknown etiologies. We previously showed that the transcription factor Krüppel-like factor 9 (KLF9) influences the expression and/or transcriptional activity of receptors for estrogen and progesterone in endometria...

  7. Evolving mechanisms of action of alverine citrate on phasic smooth muscles

    PubMed Central

    Hayase, M; Hashitani, H; Suzuki, H; Kohri, K; Brading, A F

    2007-01-01

    Background and purpose: We have investigated the mechanisms underlying the paradoxical ability of the antispasmodic, alverine, to enhance spontaneous activity in smooth muscles while suppressing evoked activity. Experimental approach: The effects of alverine on spontaneous and induced contractile activity were examined in preliminary experiments with various smooth muscles. More detailed effects were also investigated by recording membrane potential, intracellular Ca2+ concentration ([Ca2+]i) and tension from single-bundle detrusor smooth muscle (DSM) of the guinea-pig urinary bladder. Key results: Alverine (10 μM) increased the frequency and amplitude of spontaneous action potentials, transient increases in [Ca2+]i and associated contractions. Alverine also decreased action potential rate of decay, suggesting inhibition of L-type Ca channel inactivation. Charybdotoxin (50 nM) but neither cyclopiazonic acid (10 μM) nor Bay K 8644 (10 μM) attenuated alverine-induced enhancement of spontaneous contractions. Alverine suppressed contractions produced by high K (40 mM) or ACh (10 μM), without affecting electrical responses and with little suppression of increases in [Ca2+]i. This feature was very similar to that of the effects of the Rho kinase inhibitor Y-27632 (10 μM). Conclusions and implications: Alverine may increase Ca influx during action potentials due to inhibition of the inactivation of L-type Ca channels, but may also suppress evoked activity by inhibiting the sensitivity of contractile proteins to Ca2+. The proportional contribution of Ca-dependent and Ca-independent contractions in DSM may differ between spontaneous and evoked activity, necessitating further investigations into the interactions between these pathways for assessing the therapeutic potential of alverine to treat DSM dysfunction. PMID:17934514

  8. Extinction and reinstatement of phasic dopamine signals in the nucleus accumbens core during Pavlovian conditioning.

    PubMed

    Sunsay, Ceyhun; Rebec, George V

    2014-10-01

    The prediction-error model of dopamine (DA) signaling has largely been confirmed with various appetitive Pavlovian conditioning procedures and has been supported in tests of Pavlovian extinction. Studies have repeatedly shown, however, that extinction does not erase the original memory of conditioning as the prediction-error model presumes, putting the model at odds with contemporary views that treat extinction as an episode of learning rather than unlearning of conditioning. Here, we combined fast-scan cyclic voltammetry (FSCV) with appetitive Pavlovian conditioning to assess DA release directly during extinction and reinstatement. DA was monitored in the nucleus accumbens core, which plays a key role in reward processing. Following at least 4 daily sessions of 16 tone-food pairings, fast-scan cyclic voltammetry was performed while rats received additional tone-food pairings followed by tone alone presentations (i.e., extinction). Acquisition memory was reinstated with noncontingent presentations of reward and then tested with cue presentation. Tone-food pairings produced transient (1- to 3-s) DA release in response to tone. During extinction, the amplitude of the DA response decreased significantly. Following presentation of 2 noncontingent food pellets, subsequent tone presentation reinstated the DA signal. Our results support the prediction-error model for appetitive Pavlovian extinction but not for reinstatement.

  9. Reward-Induced Phasic Dopamine Release in the Monkey Ventral Striatum and Putamen

    PubMed Central

    Weitemier, Adam; Inoue, Masato

    2015-01-01

    In-vivo voltammetry has successfully been used to detect dopamine release in rodent brains, but its application to monkeys has been limited. We have previously detected dopamine release in the caudate of behaving Japanese monkeys using diamond microelectrodes (Yoshimi 2011); however it is not known whether the release pattern is the same in various areas of the forebrain. Recent studies have suggested variations in the dopaminergic projections to forebrain areas. In the present study, we attempted simultaneous recording at two locations in the striatum, using fast-scan cyclic voltammetry (FSCV) on carbon fibers, which has been widely used in rodents. Responses to unpredicted food and liquid rewards were detected repeatedly. The response to the liquid reward after conditioned stimuli was enhanced after switching the prediction cue. These characteristics were generally similar between the ventral striatum and the putamen. Overall, the technical application of FSCV recording in multiple locations was successful in behaving primates, and further voltammetric recordings in multiple locations will expand our knowledge of dopamine reward responses. PMID:26110516

  10. Does phasic trauma treatment make patients with dissociative identity disorder treatment more dissociative?

    PubMed

    Brand, Bethany; Loewenstein, Richard J

    2014-01-01

    Proponents of the iatrogenic model of the etiology of dissociative identity disorder (DID) have expressed concern that treatment focused on direct engagement and interaction with dissociated self-states harms DID patients. However, empirical data have shown that this type of DID treatment is beneficial. Analyzing data from the prospective Treatment of Patients With Dissociative Disorders (TOP DD) Study, we test empirically whether DID treatment is associated with clinically adverse manifestations of dissociated self-states: acting so differently that one feels like different people, hearing voices, and dissociative amnesia. We show that, over the course of the study, there were significant decreases in feeling like different people and hearing voices. These results indicate that this form of DID treatment does not lead to symptomatic worsening in these dimensions, as predicted by the iatrogenic model. Indeed, treatment provided by TOP DD therapists reduced, rather than increased, the extent to which patients experienced manifestations of pathological dissociation. Because severe symptomatology and impairment are associated with DID, iatrogenic harm may come from depriving DID patients of treatment that targets DID symptomatology. PMID:24377972

  11. Phasic dopamine release in the rat nucleus accumbens symmetrically encodes a reward prediction error term.

    PubMed

    Hart, Andrew S; Rutledge, Robb B; Glimcher, Paul W; Phillips, Paul E M

    2014-01-15

    Making predictions about the rewards associated with environmental stimuli and updating those predictions through feedback is an essential aspect of adaptive behavior. Theorists have argued that dopamine encodes a reward prediction error (RPE) signal that is used in such a reinforcement learning process. Recent work with fMRI has demonstrated that the BOLD signal in dopaminergic target areas meets both necessary and sufficient conditions of an axiomatic model of the RPE hypothesis. However, there has been no direct evidence that dopamine release itself also meets necessary and sufficient criteria for encoding an RPE signal. Further, the fact that dopamine neurons have low tonic firing rates that yield a limited dynamic range for encoding negative RPEs has led to significant debate about whether positive and negative prediction errors are encoded on a similar scale. To address both of these issues, we used fast-scan cyclic voltammetry to measure reward-evoked dopamine release at carbon fiber electrodes chronically implanted in the nucleus accumbens core of rats trained on a probabilistic decision-making task. We demonstrate that dopamine concentrations transmit a bidirectional RPE signal with symmetrical encoding of positive and negative RPEs. Our findings strengthen the case that changes in dopamine concentration alone are sufficient to encode the full range of RPEs necessary for reinforcement learning.

  12. Does phasic trauma treatment make patients with dissociative identity disorder treatment more dissociative?

    PubMed

    Brand, Bethany; Loewenstein, Richard J

    2014-01-01

    Proponents of the iatrogenic model of the etiology of dissociative identity disorder (DID) have expressed concern that treatment focused on direct engagement and interaction with dissociated self-states harms DID patients. However, empirical data have shown that this type of DID treatment is beneficial. Analyzing data from the prospective Treatment of Patients With Dissociative Disorders (TOP DD) Study, we test empirically whether DID treatment is associated with clinically adverse manifestations of dissociated self-states: acting so differently that one feels like different people, hearing voices, and dissociative amnesia. We show that, over the course of the study, there were significant decreases in feeling like different people and hearing voices. These results indicate that this form of DID treatment does not lead to symptomatic worsening in these dimensions, as predicted by the iatrogenic model. Indeed, treatment provided by TOP DD therapists reduced, rather than increased, the extent to which patients experienced manifestations of pathological dissociation. Because severe symptomatology and impairment are associated with DID, iatrogenic harm may come from depriving DID patients of treatment that targets DID symptomatology.

  13. T-wave amplitude: relationships to phasic RSA and heart period changes.

    PubMed

    Kline, K P; Ginsburg, G P; Johnston, J R

    1998-08-01

    T-Wave Amplitude (TWA) has been suggested as an indicator of sympathetic influence on myocardial performance, but critics have argued that TWA is confounded by parasympathetic influence or that it is a non-specific feature of tachycardia. To help clarify the issue, we examined TWA as a function of parasympathetic activity, using cardiac vagal control as measured by high frequency components of heart period variability (respiratory sinus arrhythmia) and of interbeat intervals (IBI), across several stressful tasks. Sixteen male subjects were exposed to Valsalva, Serial Subtraction and Cold-Pressor tasks. After controlling for between-person variance, it was found that RSA did not contribute to TWA and that IBI contributed dependably to TWA only during the Valsalva maneuver, when heart rate was driven very high. In light of these results, we recommend that TWA continue to be considered a candidate indicator of sympathetic influence on myocardial performance, although caution should be used if heart rate is dramatically elevated.

  14. Reward-Induced Phasic Dopamine Release in the Monkey Ventral Striatum and Putamen.

    PubMed

    Yoshimi, Kenji; Kumada, Shiori; Weitemier, Adam; Jo, Takayuki; Inoue, Masato

    2015-01-01

    In-vivo voltammetry has successfully been used to detect dopamine release in rodent brains, but its application to monkeys has been limited. We have previously detected dopamine release in the caudate of behaving Japanese monkeys using diamond microelectrodes (Yoshimi 2011); however it is not known whether the release pattern is the same in various areas of the forebrain. Recent studies have suggested variations in the dopaminergic projections to forebrain areas. In the present study, we attempted simultaneous recording at two locations in the striatum, using fast-scan cyclic voltammetry (FSCV) on carbon fibers, which has been widely used in rodents. Responses to unpredicted food and liquid rewards were detected repeatedly. The response to the liquid reward after conditioned stimuli was enhanced after switching the prediction cue. These characteristics were generally similar between the ventral striatum and the putamen. Overall, the technical application of FSCV recording in multiple locations was successful in behaving primates, and further voltammetric recordings in multiple locations will expand our knowledge of dopamine reward responses.

  15. Quantification of tonic and phasic muscle activity in REM sleep behavior disorder.

    PubMed

    Mayer, Geert; Kesper, Karl; Ploch, Thomas; Canisius, Sebastian; Penzel, Thomas; Oertel, Wolfgang; Stiasny-Kolster, Karin

    2008-02-01

    REM sleep behavior disorder (RBD) is characterized by excessive tone of the chin muscle and limb movement during sleep. In the past, quantification of increased muscle tone in REM sleep has been performed visually, using no stringent criteria. The aim of this study was to develop an automatic analysis, allowing the quantification of muscle activity and its amplitude for all sleep stages, with a focus on REM sleep in patients with RBD. Forty-eight patients (27 male, 21 female) with RBD were included in the analysis. Twenty-one had idiopathic RBD; 28 had narcolepsy plus RBD. Twenty-five patients without confirmed sleep disorder served as control subjects. The amplitude of the EMG was generated from the difference of the upper and lower envelope of the mentalis muscle recordings. By smoothing the amplitude curve, a threshold curve was defined. Any muscle activity beyond the threshold curve was defined as motor activity. The means of the motor activity per second were summarized statistically and calculated for each sleep stage. Due to variable distribution of REM sleep, the latter was assigned to respective quartiles of the recorded night. Muscle activity was defined according to a histogram as short-lasting (<0.5 second) and long-lasting (>0.5 second) activity. No difference in the distribution of REM sleep/quartile and mean muscle tone throughout the sleep cycle could be found within the RBD groups and control subjects. Muscle activity was in the range of 200 ms. No clusters or regular distribution of muscle activity were found. Long muscle activity in the group with manifest clinical RBD was significantly higher than in control subjects, whereas it was nonsignificantly higher in subclinical RBD. The correlation between the frequency of long muscle activity in REM sleep and age was highly significant only for patients with idiopathic RBD. Automatic analysis of muscle activity in sleep is a reliable, easy method that may easily be used in the evaluation for REM sleep behavior disorder, creating indices of muscle activity similar to the indices for sleep apnea or PLMS. Together with the overt behavior, the analyses provides an important tool to get a deeper insight into the pathophysiology of RBD. Long movements appear to represent the motor disinhibition in REM sleep more distinct than short movements. The positive correlation of age and increased motor activity in REM sleep in idiopathic RBD highlights the idea of age dependant motor disinhibition as a continuum of a neurodegenerative disorder, which in narcolepsy patients with RBD only seems to happen as a single temporal event at onset of the disorder.

  16. Phasic changes in intracellular pH during action potentials of sheep Purkinje fibres.

    PubMed

    Pressler, M L

    1988-01-01

    Regulation of intracellular pH (pHi) and the relationship between H+ and Ca2+ may vary during activity. Ion-selective microelectrodes were used to record pHi during action potentials of sheep Purkinje fibres prolonged by low temperature (21 degrees C) and elevated CO2 content. Intracellular pH also was measured during changes in extracellular calcium concentration, [Ca2+]o. Cytosolic alkalinization (peak pHi change, 0.03-0.05) was observed during the long action-potential plateau and transient acidification (0.01-0.02 units) upon repolarization. Potassium-induced depolarization to plateau potentials (i.e. to -15 +/- 2 mV) simulated the peak magnitude of the alkalinization. However, compensation for the alkalinization occurred at a faster rate during the action potential (8.9 +/- 4.3 nM/min) than during K+ depolarization (1.2 +/- 0.5 nM/min). In comparison, the cytoplasm acidified in resting fibres (0.06-0.07 log units) during changes of [Ca2+]o thought to increase intracellular calcium concentration. Alterations of pHi were translated into changes of proton concentration ([H+]i). Ten- to twenty-fold elevation of [Ca2+]o evoked a comparable change in [H+]i (mean increase, 5.7 nM) but oppositely directed from that during the plateau (mean decrease, 8.8 nM). The findings in resting fibres seem consistent with displacement of bound protons by Ca2+. In contrast, the initial change in pHi during the plateau is proposed to be consequent to Ca2+-release from sarcoplasmic reticulum and/or phosphocreatine hydrolysis coupled to ATP regeneration.

  17. Phasic and Tonic mGlu7 Receptor Activity Modulates the Thalamocortical Network

    PubMed Central

    Tassin, Valériane; Girard, Benoît; Chotte, Apolline; Fontanaud, Pierre; Rigault, Delphine; Kalinichev, Mikhail; Perroy, Julie; Acher, Francine; Fagni, Laurent; Bertaso, Federica

    2016-01-01

    Mutation of the metabotropic glutamate receptor type 7 (mGlu7) induces absence-like epileptic seizures, but its precise role in the somatosensory thalamocortical network remains unknown. By combining electrophysiological recordings, optogenetics, and pharmacology, we dissected the contribution of the mGlu7 receptor at mouse thalamic synapses. We found that mGlu7 is functionally expressed at both glutamatergic and GABAergic synapses, where it can inhibit neurotransmission and regulate short-term plasticity. These effects depend on the PDZ-ligand of the receptor, as they are lost in mutant mice. Interestingly, the very low affinity of mGlu7 receptors for glutamate raises the question of how it can be activated, namely at GABAergic synapses and in basal conditions. Inactivation of the receptor activity with the mGlu7 negative allosteric modulator (NAM), ADX71743, enhances thalamic synaptic transmission. In vivo administration of the NAM induces a lethargic state with spindle and/or spike-and-wave discharges accompanied by a behavioral arrest typical of absence epileptic seizures. This provides evidence for mGlu7 receptor-mediated tonic modulation of a physiological function in vivo preventing synchronous and potentially pathological oscillations. PMID:27199672

  18. Age-Related Phasic Patterns of Mitochondrial Maintenance in Adult Caenorhabditis elegans Neurons

    PubMed Central

    Morsci, Natalia S.; Hall, David H.

    2016-01-01

    Aging is associated with cognitive decline and increasing risk of neurodegeneration. Perturbation of mitochondrial function, dynamics, and trafficking are implicated in the pathogenesis of several age-associated neurodegenerative diseases. Despite this fundamental importance, the critical understanding of how organismal aging affects lifetime neuronal mitochondrial maintenance remains unknown, particularly in a physiologically relevant context. To address this issue, we performed a comprehensive in vivo analysis of age-associated changes in mitochondrial morphology, density, trafficking, and stress resistance in individual Caenorhabditis elegans neurons throughout adult life. Adult neurons display three distinct stages of increase, maintenance, and decrease in mitochondrial size and density during adulthood. Mitochondrial trafficking in the distal neuronal processes declines progressively with age starting from early adulthood. In contrast, long-lived daf-2 mutants exhibit delayed age-associated changes in mitochondrial morphology, constant mitochondrial density, and maintained trafficking rates during adulthood. Reduced mitochondrial load at late adulthood correlates with decreased mitochondrial resistance to oxidative stress. Revealing aging-associated changes in neuronal mitochondria in vivo is an essential precedent that will allow future elucidation of the mechanistic causes of mitochondrial aging. Thus, our study establishes the critical foundation for the future analysis of cellular pathways and genetic and pharmacological factors regulating mitochondrial maintenance in aging- and disease-relevant conditions. SIGNIFICANCE STATEMENT Using Caenorhabditis elegans as a model, we address long-standing questions: How does aging affect neuronal mitochondrial morphology, density, trafficking, and oxidative stress resistance? Are these age-related changes amenable to genetic manipulations that slow down the aging process? Our study illustrates that mitochondrial trafficking declines progressively from the first day of adulthood, whereas mitochondrial size, density, and resistance to oxidative stress undergo three distinct stages: increase in early adulthood, maintenance at high levels during mid-adulthood, and decline during late adulthood. Thus, our study characterizes mitochondrial aging profile at the level of a single neuron in its native environment and establishes the critical foundation for the future genetic and pharmacological dissection of factors that influence long-term mitochondrial maintenance in neurons. PMID:26818523

  19. The analgesic effect of Carum copticum extract and morphine on phasic pain in mice.

    PubMed

    Dashti-Rahmatabadi, Mohammad Hossein; Hejazian, Seyed Hassan; Morshedi, Abbas; Rafati, Ali

    2007-01-19

    Pain is a universal complaint, which needs further investigations for new pain relieving agents. Carum copticum (L.) Sprague ex Turrill is a plant in Umbelliferae family, which is mentioned to have some therapeutic effects on headache and joint pains in Iranian traditional literature, but there are not enough scientific reports to prove its effects on pain. So, we conducted to design an experimental clinical trial study to assess and compare the analgesic effect of ethanolic extract of Carum copticum fruit with morphine by using a tail-flick analgesiometer device. Our results indicate that the test drug produced significant increase in tail-flick latency (TFL) during 2h post-drug administration (p<0.05). The peak of the effect was observed at 45min after drug injection, which was comparable to that of 1mg/kg morphine (i.p.). Positive results in this type of analgesiometric test indicate that the antinociceptive action may be of the opoid type. The present study supports the claims of Iranian traditional medicine showing that Carum copticum extract possesses a clear-cut analgesic effect. However, further investigations are required to evaluate the efficacy and safety of this herbal medication in man.

  20. Endogenous cholinergic inputs and local circuit mechanisms govern the phasic mesolimbic dopamine response to nicotine.

    PubMed

    Graupner, Michael; Maex, Reinoud; Gutkin, Boris

    2013-01-01

    Nicotine exerts its reinforcing action by stimulating nicotinic acetylcholine receptors (nAChRs) and boosting dopamine (DA) output from the ventral tegmental area (VTA). Recent data have led to a debate about the principal pathway of nicotine action: direct stimulation of the DAergic cells through nAChR activation, or disinhibition mediated through desensitization of nAChRs on GABAergic interneurons. We use a computational model of the VTA circuitry and nAChR function to shed light on this issue. Our model illustrates that the α4β2-containing nAChRs either on DA or GABA cells can mediate the acute effects of nicotine. We account for in vitro as well as in vivo data, and predict the conditions necessary for either direct stimulation or disinhibition to be at the origin of DA activity increases. We propose key experiments to disentangle the contribution of both mechanisms. We show that the rate of endogenous acetylcholine input crucially determines the evoked DA response for both mechanisms. Together our results delineate the mechanisms by which the VTA mediates the acute rewarding properties of nicotine and suggest an acetylcholine dependence hypothesis for nicotine reinforcement.

  1. Contingent negative variation indicates phasic arousal for externally cued unilateral eye blink in human subjects.

    PubMed

    Strenge, H; Kropp, P; Hoffmeister, J; Verri, A; Galli, C; Gerber, W D

    1999-04-30

    The contingent negative variation (CNV) as a slow cortical potential was used to investigate cortical processing of externally cued, voluntary unilateral eye blink. Probands blinked as a response within a modified two-stimulus reaction time paradigm. Reaction time and amplitudes of CNV were determined. The activity of the orbicularis oculi muscles (OO) was registered by surface electromyography (EMG). Probands who performed unilateral eye blinks with accurately inhibiting contralateral OO activity showed a significantly higher negativity of the early CNV component compared with the bilateral eye blink condition. This effect was confined to the beginning of unilateral blinking performance. It is suggested that the unilateral eye blink is a challenging motor task, initially requiring an increased cortically driven arousal and attention as revealed by increased early CNV components. PMID:10336183

  2. Endocannabinoid-Dependent Modulation of Phasic Dopamine Signaling Encodes External and Internal Reward-Predictive Cues

    PubMed Central

    Wenzel, Jennifer M.; Cheer, Joseph F.

    2014-01-01

    The mesolimbic dopamine (DA) system plays an integral role in incentive motivation and reward seeking and a growing body of evidence identifies signal transduction at cannabinoid receptors as a critical modulator of this system. Indeed, administration of exogenous cannabinoids results in burst firing of DA neurons of the ventral tegmental area and increases extracellular DA in the nucleus accumbens (NAcc). Implementation of fast-scan cyclic voltammetry (FSCV) confirms the ability of cannabinoids to augment DA within the NAcc on a subsecond timescale. The use of FSCV along with newly developed highly selective pharmacological compounds advances our understanding of how cannabinoids influence DA transmission and highlights a role for endocannabinoid-modulated subsecond DAergic activation in the incentive motivational properties of not only external, but also internal reward-predictive cues. For example, our laboratory has recently demonstrated that in mice responding under a fixed-interval (FI) schedule for food reinforcement, fluctuations in NAcc DA signal the principal cue predictive of reinforcer availability – time. That is, as the interval progresses, NAcc DA levels decline leading to accelerated food seeking and the resulting characteristic FI scallop pattern of responding. Importantly, administration of WIN 55,212-2, a synthetic cannabinoid agonist, or JZL184, an indirect cannabinoid agonist, increases DA levels during the interval and disrupts this pattern of responding. Along with a wealth of other reports, these results illustrate the role of cannabinoid receptor activation in the regulation of DA transmission and the control of temporally guided reward seeking. The current review will explore the striatal beat frequency model of interval timing as it pertains to cannabinoid signaling and propose a neurocircuitry through which this system modulates interoceptive time cues. PMID:25225488

  3. Endocannabinoid-dependent modulation of phasic dopamine signaling encodes external and internal reward-predictive cues.

    PubMed

    Wenzel, Jennifer M; Cheer, Joseph F

    2014-01-01

    The mesolimbic dopamine (DA) system plays an integral role in incentive motivation and reward seeking and a growing body of evidence identifies signal transduction at cannabinoid receptors as a critical modulator of this system. Indeed, administration of exogenous cannabinoids results in burst firing of DA neurons of the ventral tegmental area and increases extracellular DA in the nucleus accumbens (NAcc). Implementation of fast-scan cyclic voltammetry (FSCV) confirms the ability of cannabinoids to augment DA within the NAcc on a subsecond timescale. The use of FSCV along with newly developed highly selective pharmacological compounds advances our understanding of how cannabinoids influence DA transmission and highlights a role for endocannabinoid-modulated subsecond DAergic activation in the incentive motivational properties of not only external, but also internal reward-predictive cues. For example, our laboratory has recently demonstrated that in mice responding under a fixed-interval (FI) schedule for food reinforcement, fluctuations in NAcc DA signal the principal cue predictive of reinforcer availability - time. That is, as the interval progresses, NAcc DA levels decline leading to accelerated food seeking and the resulting characteristic FI scallop pattern of responding. Importantly, administration of WIN 55,212-2, a synthetic cannabinoid agonist, or JZL184, an indirect cannabinoid agonist, increases DA levels during the interval and disrupts this pattern of responding. Along with a wealth of other reports, these results illustrate the role of cannabinoid receptor activation in the regulation of DA transmission and the control of temporally guided reward seeking. The current review will explore the striatal beat frequency model of interval timing as it pertains to cannabinoid signaling and propose a neurocircuitry through which this system modulates interoceptive time cues. PMID:25225488

  4. Selective vulnerability and pruning of phasic motoneuron axons in motoneuron disease alleviated by CNTF.

    PubMed

    Pun, San; Santos, Alexandre Ferrão; Saxena, Smita; Xu, Lan; Caroni, Pico

    2006-03-01

    Neurodegenerative diseases can have long preclinical phases and insidious progression patterns, but the mechanisms of disease progression are poorly understood. Because quantitative accounts of neuronal circuitry affected by disease have been lacking, it has remained unclear whether disease progression reflects processes of stochastic loss or temporally defined selective vulnerabilities of distinct synapses or axons. Here we derive a quantitative topographic map of muscle innervation in the hindlimb. We show that in two mouse models of motoneuron disease (G93A SOD1 and G85R SOD1), axons of fast-fatiguable motoneurons are affected synchronously, long before symptoms appear. Fast-fatigue-resistant motoneuron axons are affected at symptom-onset, whereas axons of slow motoneurons are resistant. Axonal vulnerability leads to synaptic vesicle stalling and accumulation of BC12a1-a, an anti-apoptotic protein. It is alleviated by ciliary neurotrophic factor and triggers proteasome-dependent pruning of peripheral axon branches. Thus, motoneuron disease involves predictable, selective vulnerability patterns by physiological subtypes of axons, episodes of abrupt pruning in the target region and compensation by resistant axons.

  5. Relationship between phasic changes in human skin blood flow and autonomic tone.

    PubMed

    Bernardi, L; Rossi, M; Fratino, P; Finardi, G; Mevio, E; Orlandi, C

    1989-01-01

    Heart rate beat-to-beat oscillations synchronous with respiration and blood pressure waves, have been found to be a marker of sympathovagal interaction in man and animals. Oscillations of heart rate, respiration, and cutaneous blood flow were simultaneously recorded to assess the relationship between autonomic nervous control and cutaneous circulation in a group of 21 healthy subjects and in a group of 6 healthy patients after brachial plexus anesthesia and consequent sympathetic blockade. In the first group, changes in posture were employed to modify autonomic tone. Relative changes in cutaneous blood flow were recorded by laser-Doppler flowmetry. Spectral analysis techniques (cross-correlation) were used to quantify the relationship between oscillations common to the recorded signals. A standing maneuver induced a significant decrease of the cross-correlation between respiratory and heart rate fluctuations (from 4.93 +/- 0.16 to 4.44 +/- 0.16 a.u.; P less than 0.001), and a significant increase of the cross-correlation between heart rate and skin blood flow fluctuations (from 0.64 +/- 0.31 to 1.33 +/- 0.21 a.u.; P less than 0.001), but did not modify the cross-correlation between respiratory and skin blood flow fluctuations (from 2.87 +/- 0.15 to 3.04 +/- 0.14 a.u.; NS). After the standing maneuver the maximum correlation between heart rate and skin blood flow was always due to oscillations in the range of 0.1 Hz (or 10-sec period), similar to the oscillations described in large arteries. Sympathetic blockade reduced significantly the cross-correlation between heart rate and skin blood flow (P less than 0.001). These results suggest that the cross-correlation between skin blood flow and heart rate at 10-sec period fluctuations can be used as an index of the influence of the autonomic tone on skin blood circulation.

  6. Bidirectional modulation of cocaine-expectancy by phasic glutamate fluctuations in the nucleus accumbens

    PubMed Central

    Suto, Nobuyoshi; Elmer, Greg I.; Wang, Bin; You, Zhi-Bing; Wise, Roy A.

    2013-01-01

    While glutamate in the nucleus accumbens (NAS) contributes to the promotion of drug-seeking by drug-predictive cues, it also appears to play a role in the inhibition of drug-seeking following extinction procedures. Thus we measured extracellular fluctuations of NAS glutamate in response to discriminative stimuli that signaled either cocaine availability or cocaine omission. We trained rats to self-administer intravenous cocaine and then to recognize discriminative odor cues that predicted either sessions where cocaine was available or alternating sessions where it was not (saline substituted for cocaine). Whereas responding in cocaine availability sessions remained stable, responding in cocaine omission sessions progressively declined to chance levels. We then determined the effects of each odor cue on extracellular glutamate in the core and shell subregions of NAS preceding and accompanying lever-pressing under an extinction condition. Glutamate levels were elevated in both core and shell by the availability odor and depressed in the core but not the shell by the omission odor. Infusion of kynurenic acid (an antagonist for ionotropic glutamate receptors) into core but not shell suppressed responding associated with the availability odor, but had no effect on the suppression associated with the omission odor. Thus cocaine-predictive cues appear to promote cocaine-seeking in part by elevating glutamatergic neurotransmission in the core of NAS, whereas cocaine-omission cues appear to suppress cocaine-seeking in part by depressing glutamatergic receptor activation in the same region. PMID:23699516

  7. Fast Phasic Release Properties of Dopamine Studied with a Channel Biosensor

    PubMed Central

    Kress, Geraldine J.; Shu, Hong-Jin; Yu, Andrew; Taylor, Amanda; Benz, Ann; Harmon, Steve

    2014-01-01

    Few other neurotransmitters are of as intense interest to neuropsychiatry and neurology as dopamine, yet existing techniques to monitor dopamine release leave an important spatiotemporal gap in our understanding. Electrochemistry and fluorescence imaging tools have been developed to fill the gap, but these methods have important limitations. We circumvent these limitations by introducing a dopamine-gated chloride channel into rat dorsal striatal medium spiny neurons, targets of strong dopamine innervation, thereby transforming dopamine from a slow transmitter into a fast transmitter and revealing new opportunities for studying moment-to-moment regulation of dopamine release. We demonstrate pharmacological and biophysical properties of the channel that make it suitable for fast, local dopamine measurements, and we demonstrate for the first time spontaneous and evoked responses to vesicular dopamine release in the dorsal striatum. Evoked dopamine currents were separated into a fast, monosynaptic component and a slower-rising and decaying disynaptic component mediated by nicotinic receptor activation. In summary, LGC-53 represents a dopamine biosensor with properties suitable for temporal separation of distinct dopamine signals in targets of dopamine innervation. PMID:25164674

  8. Developmental Change in Feedback Processing as Reflected by Phasic Heart Rate Changes

    ERIC Educational Resources Information Center

    Crone, Eveline A.; Jennings, J. Richard; Van der Molen, Maurits W.

    2004-01-01

    Heart rate was recorded from 3 age groups (8-10, 12, and 20-26 years) while they performed a probabilistic learning task. Stimuli had to be sorted by pressing a left versus right key, followed by positive or negative feedback. Adult heart rate slowed following negative feedback when stimuli were consistently mapped onto the left or right key…

  9. Endocannabinoid-dependent modulation of phasic dopamine signaling encodes external and internal reward-predictive cues.

    PubMed

    Wenzel, Jennifer M; Cheer, Joseph F

    2014-01-01

    The mesolimbic dopamine (DA) system plays an integral role in incentive motivation and reward seeking and a growing body of evidence identifies signal transduction at cannabinoid receptors as a critical modulator of this system. Indeed, administration of exogenous cannabinoids results in burst firing of DA neurons of the ventral tegmental area and increases extracellular DA in the nucleus accumbens (NAcc). Implementation of fast-scan cyclic voltammetry (FSCV) confirms the ability of cannabinoids to augment DA within the NAcc on a subsecond timescale. The use of FSCV along with newly developed highly selective pharmacological compounds advances our understanding of how cannabinoids influence DA transmission and highlights a role for endocannabinoid-modulated subsecond DAergic activation in the incentive motivational properties of not only external, but also internal reward-predictive cues. For example, our laboratory has recently demonstrated that in mice responding under a fixed-interval (FI) schedule for food reinforcement, fluctuations in NAcc DA signal the principal cue predictive of reinforcer availability - time. That is, as the interval progresses, NAcc DA levels decline leading to accelerated food seeking and the resulting characteristic FI scallop pattern of responding. Importantly, administration of WIN 55,212-2, a synthetic cannabinoid agonist, or JZL184, an indirect cannabinoid agonist, increases DA levels during the interval and disrupts this pattern of responding. Along with a wealth of other reports, these results illustrate the role of cannabinoid receptor activation in the regulation of DA transmission and the control of temporally guided reward seeking. The current review will explore the striatal beat frequency model of interval timing as it pertains to cannabinoid signaling and propose a neurocircuitry through which this system modulates interoceptive time cues.

  10. Effect of dynamic cardiomyoplasty on phasic coronary arterial flow velocity in canine hearts.

    PubMed

    Tsukube, T; Okada, M; Mukai, T; Kashem, M A; Ota, T

    1994-10-01

    The usefulness of dynamic cardiomyoplasty has been demonstrated repeatedly, both experimentally and clinically. Although clinical applications of dynamic cardiomyoplasty to ischemic heart disease have been reported, its effect on the coronary blood flow has never been discussed. Therefore, we tested the hypothesis that dynamic cardiomyoplasty might adversely affect coronary arterial blood flow through compression of the coronary arteries during systolic skeletal muscular contraction and incomplete relaxation of the skeletal muscle flap during diastole. Dynamic cardiomyoplasty was performed in seven mongrel dogs with the use of a left latissimus dorsi-muscle flap, paced synchronously with the R wave of the electrocardiogram. A 3F Doppler catheter was placed in the left main trunk of the coronary artery to assess the instantaneous changes of coronary flow velocity by fast Fourier transformation analysis, We compared systolic and diastolic properties during assisted versus unassisted cardiac cycles by calculating the peak velocity and the time-velocity integral. During assisted cardiac cycles, a significant enhancement of coronary arterial blood flow velocity was demonstrated by significant increases in both systolic and diastolic peak velocity (26.9% +/- 6.5%, p < 0.005; 4.0% +/- 1.6%, p < 0.05, respectively) and time-velocity integral (20.9% +/- 4.8%, p < 0.05; 10.0% +/- 4.6%, p < 0.05, respectively). Enhancement of coronary arterial blood flow velocity was associated with an increase in mean aortic pressure (16.4% +/- 1.3%, p < 0.005) and descending aortic flow (67.5% +/- 5.3%, p < 0.005). Also, the improved systolic coronary arterial blood flow velocity was consistent with an increase in systolic aortic pressure (15.8% +/- 1.5%, p < 0.005), and enhancement of diastolic coronary arterial blood flow velocity was associated with an increase in diastolic aortic pressure (8.6% +/- 2.3%, p < 0.01). We concluded that coronary arterial blood flow velocity was increased by the enhancement of cardiac function as a result of dynamic cardiomyoplasty, leading to an increase of coronary perfusion pressure and cardiac output.

  11. Inhibitory effects of ginger oil on spontaneous and PGF2alpha-induced contraction of rat myometrium.

    PubMed

    Buddhakala, Nopparat; Talubmook, Chusri; Sriyotha, Poonsook; Wray, Susan; Kupittayanant, Sajeera

    2008-03-01

    Solvent extracts of ginger, the rhizome of Zingiber officinale Roscoe (Zingiberaceae), have been extensively studied for their pharmacological activities in smooth muscles. However, the effects of ginger essential oil on smooth muscle contractility have not been elucidated. The aims of the study were to investigate the effects of ginger oil on rat myometrial contractility. We particularly examined the effects on phasic contractions arising either spontaneously or with PGF (2) (alpha) stimulation. Ginger oil was obtained by hydrodistillation and its constituents analyzed using gas chromatography and mass spectrometry. Rats were humanely killed by asphyxiation with CO (2), and longitudinal uterine smooth muscles were isolated. Isometric force was measured and the effects of ginger oil studied. It was found that citral was the main constituent of ginger oil (24 %). Ginger oil inhibited spontaneous contractions with an IC (50) of 50 microL/100 mL (10 - 150 microL/100 mL). The PGF (2) (alpha)-induced contractions were also significantly reduced by ginger oil. Increases in external calcium concentration completely reversed the relaxant effects of ginger oil. This was the case for both spontaneous and PGF (2) (alpha)-induced contractions. The effects of ginger oil were indistinguishable from those of pure citral. In conclusion, ginger oil is a potent inhibitor of phasic activity in rat uterus, irrespective of how it was produced. Our data suggest that the effects are largely due to citral, and could be via inhibition of L-type Ca channels. PMID:18484528

  12. Distribution and abundance of metabotropic glutamate receptor subtype 2 in rat brain revealed by [3H]LY354740 binding in vitro and quantitative radioautography: correlation with the sites of synthesis, expression, and agonist stimulation of [35S]GTPgammas binding.

    PubMed

    Richards, Grayson; Messer, Jürg; Malherbe, Pari; Pink, Richard; Brockhaus, Manfred; Stadler, Heinz; Wichmann, Jürgen; Schaffhauser, Hervé; Mutel, Vincent

    2005-06-20

    Until recently, there was a lack of selective radioligands for the subtypes of metabotropic glutamate (mGlu) receptors. [(3)H]LY354740 ((+)-2-aminobicyclo[3,1,0]hexane-2,6-dicarboxylic acid), a selective agonist for group II receptors (mGlu2 and -3, which are negatively coupled to cAMP production), has now been used to map their brain distribution and abundance by in vitro binding and quantitative radioautography. The selective cation dependence of its binding allowed the discrimination between mGlu2 and mGlu3 receptor labeling. Thus, in the presence of Ca(2+) and Mg(2+) ions, the agonist bound selectively to mGlu2 receptors as evidenced by: 1) the correlative distribution and abundance of binding sites (highest in the lacunosum moleculare of the hippocampus and lowest in white matter) with mGlu2 receptor mRNA and protein revealed by in situ hybridization histochemistry and immunohistochemistry, respectively; 2) its selective pharmacology; and 3) the distribution of LY354740-stimulated [(35)S]GTPgammaS binding (25-97% above basal, according to the brain region), revealing G protein-coupled receptor coupling to G(i) proteins. Nonspecific binding (in the presence of 10 muM DCG-IV, a group II-selective, mGlu2-preferring, receptor agonist) was <10% of total. In adjacent sections, the distribution of binding sites for [(3)H]DCG-IV was very similar. This extensive study paves the way for investigations of the regional expression and regulation of mGlu2 receptors in human CNS diseases, such as Alzheimer's disease, which may reveal their functional roles and identify potential therapeutic drug targets. Indeed, it has recently been demonstrated (Higgins et al. [2004] Neuropharmacology 46:907-917) that pharmacological manipulation of mGlu2 receptors influences cognitive performance in the rodent. PMID:15861463

  13. SDF-1/CXCL12 modulates mitochondrial respiration of immature blood cells in a bi-phasic manner.

    PubMed

    Messina-Graham, Steven; Broxmeyer, Hal

    2016-05-01

    SDF-1/CXCL12 is a potent chemokine required for the homing and engraftment of hematopoietic stem and progenitor cells. Previous data from our group has shown that in an SDF-1/CXCL12 transgenic mouse model, lineage(-) Sca-1(+) c-Kit(+) (LSK) bone marrow cells have reduced mitochondrial membrane potential versus wild-type. These results suggested that SDF-1/CXCL12 may function to keep mitochondrial respiration low in immature blood cells in the bone marrow. Low mitochondrial metabolism helps to maintain low levels of reactive oxygen species (ROS), which can influence differentiation. To test whether SDF-1/CXCL12 regulates mitochondrial metabolism, we employed the human leukemia cell line HL-60, that expresses high levels of the SDF-1/CXCL12 receptor, CXCR4, as a model of hematopoietic progenitor cells in vitro. We treated HL-60 cells with SDF-1/CXCL12 for 2 and 24h. Oxygen consumption rates (OCR), mitochondrial-associated ATP production, mitochondrial mass, and mitochondrial membrane potential of HL-60 cells were significantly reduced at 2h and increased at 24h as compared to untreated control cells. These biphasic effects of SDF-1/CXCL12 were reproduced with lineage negative primary mouse bone marrow cells, suggesting a novel function of SDF-1/CXCL12 in modulating mitochondrial respiration by regulating mitochondrial oxidative phosphorylation, ATP production and mitochondrial content. PMID:27067482

  14. Phasic transition from goal-directed to habitual control over drug-seeking produced by conflicting reinforcer expectancy.

    PubMed

    Hogarth, Lee; Field, Matt; Rose, Abigail K

    2013-01-01

    The transition from goal-directed to habitual control over drug-seeking has been experimentally demonstrated in animals, but there have been no comparable reports in humans. Following a recent animal design, the current study employed an outcome-devaluation procedure to test whether goal-directed control over tobacco seeking would be abolished by alcohol expectancy. Eighty smokers first learned that two responses earned tobacco or chocolate points, respectively, before tobacco was devalued by health warnings and smoking satiety. Participants were then presented with either a glass of beer/wine or water with instructions that this item could be consumed after the task (alternative reward). Then choice between the tobacco and chocolate response was measured in extinction to assess goal-directed control of tobacco seeking, in a nominal Pavlovian to instrumental transfer (PIT) test to assess stimulus control of tobacco seeking, and in a reacquisition test to assess the impact of direct feedback from the outcomes. The results showed that alcohol expectancy selectively abolished goal-directed control of tobacco seeking but not stimulus control or the impact of feedback from outcomes. These data suggest that 'endogenous' retrieval of low drug value governing goal-directed regulation of drug seeking is disrupted by conflicting appraisal of an alternative reinforcer, promoting habitual control, which may play a role in relapse.

  15. Brain Correlates of Phasic Autonomic Response to Acupuncture Stimulation: An Event-Related fMRI Study

    PubMed Central

    Napadow, Vitaly; Lee, Jeungchan; Kim, Jieun; Cina, Stephen; Maeda, Yumi; Barbieri, Riccardo; Harris, Richard E.; Kettner, Norman; Park, Kyungmo

    2013-01-01

    Autonomic nervous system (ANS) response to acupuncture has been investigated by multiple studies; however, the brain circuitry underlying this response is not well understood. We applied event-related fMRI (er-fMRI) in conjunction with ANS recording (heart rate, HR; skin conductance response, SCR). Brief manual acupuncture stimuli were delivered at acupoints ST36 and SP9, while sham stimuli were delivered at control location, SH1. Acupuncture produced activation in S2, insula, and mid-cingulate cortex, and deactivation in default mode network (DMN) areas. On average, HR deceleration (HR–) and SCR were noted following both real and sham acupuncture, though magnitude of response was greater following real acupuncture and inter-subject magnitude of response correlated with evoked sensation intensity. Acupuncture events with strong SCR also produced greater anterior insula activation than without SCR. Moreover, acupuncture at SP9, which produced greater SCR, also produced stronger sharp pain sensation, and greater anterior insula activation. Conversely, acupuncture-induced HR– was associated with greater DMN deactivation. Between-event correlation demonstrated that this association was strongest for ST36, which also produced more robust HR–. In fact, DMN deactivation was significantly more pronounced across acupuncture stimuli producing HR–, versus those events characterized by acceleration (HR+). Thus, differential brain response underlying acupuncture stimuli may be related to differential autonomic outflows and may result from heterogeneity in evoked sensations. Our er-fMRI approach suggests that ANS response to acupuncture, consistent with previously characterized orienting and startle/defense responses, arises from activity within distinct subregions of the more general brain circuitry responding to acupuncture stimuli. PMID:22504841

  16. A role for phasic dopamine release within the nucleus accumbens in encoding aversion: a review of the neurochemical literature.

    PubMed

    Wenzel, Jennifer M; Rauscher, Noah A; Cheer, Joseph F; Oleson, Erik B

    2015-01-21

    Survival is dictated by an organism's fitness in approaching positive stimuli and avoiding harm. While a rich literature outlines a role for mesolimbic dopamine in reward and appetitive behaviors, dopamine's involvement in aversion and avoidance behaviors remains controversial. Debate surrounding dopamine's function in the processing of negative stimuli likely stems from conflicting results reported by single-unit electrophysiological studies. Indeed, a number of studies suggest that midbrain dopaminergic cells are inhibited by the presentation of negative or fearful stimuli, while others report no change, or even an increase, in their activity. These disparate results may be due to population heterogeneity. Recent evidence demonstrates that midbrain dopamine neurons are heterogeneous in their projection targets, responses to environmental stimuli, pharmacology, and influences on motivated behavior. Thus, in order to assemble an accurate account of dopamine function during aversive stimulus experience and related behavior, it is necessary to examine the functional output of dopamine neural activity at mesolimbic terminal regions. This Review presents a growing body of evidence that dopamine release in the nucleus accumbens encodes not only reward, but also aversion. For example, our laboratory recently utilized fast-scan cyclic voltammetry to show that real-time changes in accumbal dopamine release are detected when animals are presented with predictors of aversion and its avoidance. These data, along with other reports, support a considerably more nuanced view of dopamine neuron function, wherein accumbal dopamine release is differentially modulated by positive and negative affective stimuli to promote adaptive behaviors. PMID:25491156

  17. Assessment of Myometrial Concentrations of Oestrogen and Progesterone Receptors in the Lower Uterine Segment of Full-Term Pregnancies in Presence or Absence of Labour

    PubMed Central

    de Arruda, Joana Soares; Simões, Manuel de Jesus; Kulay Júnior, Luiz

    2013-01-01

    Objective. To assess the concentration of progesterone (PRs) and oestrogen (ORs) receptors of myometrium of full-term pregnant women in the myometrium of lower segment of the uterus in relationship with presence or absence of labour. Methods. This was a cross-sectional prospective study with 21 pregnant women, being 6 in labour (Group I) and 15 without labour (Group II). The biopsy of myometrium was realized during caesarian section, and the excised tissue was stained using immunohistochemical techniques for the quantification of the receptors, and with the aid of image-analysis software, the numbers of receptors for each hormone were determined spectrophotometrically. The Mann-Whitney test was used to compare the pregnant women in each study group with respect to the numbers of ORs and PRs. The Wilcoxon test was used to compare the concentration of ORs and PRs in each group separately. Results. The mean of gestational age was 39 weeks, (range, 37 to 41 weeks). The medians of PRs and ORs in pregnant women in labour (Group I) were 29.3 (range, 24.6–30.2) and 32.3 (range, 22.9–49.0), respectively. The medians of PRs and ORs in pregnant women without labour (Group II) were 43.6 (range, 23.6–70) and 43.9 (range, 18.3–62.6), respectively. We did not observe significant differences of the number of ORs and PRs in both groups (P = 0.13 and 0.37, resp.). The number of ORs was statistically more than that of PRs in Group II (Z calculated = 16.00). Conclusion. The concentrations of PRs and ORs were similar in the myometrium of the lower uterine segment of pregnant women during and without labour, but the concentration of ORs was more than that of PRs in the myometrium of the lower uterine segment of pregnant women without labour. PMID:23819052

  18. /sup 45/Ca efflux for myometrial cells: comparison of the effects of prostaglandin F/sub 2/. cap alpha. (PGF/sub 2/), oxytocin (OT) and arachidonate (A)

    SciTech Connect

    Katona, G.; Molnar, M.; Toth, M.; Hertelendy, F.

    1986-03-01

    The aim of this study was to measure PGF/sub 2..cap alpha../-induced Ca/sup 2 +/ release from uterine cells and to compare this to the actions of OT and A. Smooth muscle cells isolated from the uterus (shell gland) of laying hens were cultured for 7 days in M199 plus 10% fetal calf serum. The cells were treated with digitonin (20..mu..M) and preloaded with /sup 45/Ca for 40 min. Addition of PGF/sub 2..cap alpha../ caused a biphasic /sup 45/Ca-efflux. There was a small but significant /sup 45/Ca-release within 30 sec (rapid phase) followed by a larger one within 7 min (slow phase). In comparison, both OT and A stimulated /sup 45/Ca efflux during a single, slow phase. The maximal effect of A was observed at < 7 min, whereas that of OT was slower, peaking after 7 min. Mepacrin, an inhibitor of A release, attenuated the action of OT without having any effect on A promoted /sup 45/Ca-efflux. Indomethacin, an inhibitor of PG synthase, failed to suppress the Ca-releasing effect of A suggesting the A itself or a lipoxygenase product may have been responsible for the observed effects. Moreover, these results provide suggestive evidence that A release is an important step in the action of various uterotonic agents converging on the mobilization of intracellular Ca.

  19. [Changes in polarization of myometrial cells plasma and internal mitochondrial membranes under calixarenes action as inhibitors of plasma membrane Na+, K+-ATPase].

    PubMed

    Danylovych, H V; Danylovych, Iu V; Kolomiiets', O V; Kosterin, S O; Rodik, R V; Cherenok, S O; Kal'chenko, V I; Chunikhin, O Iu; Horchev, V F; Karakhim, S O

    2012-01-01

    The influence of supramolecular macrocyclic compounds--calix[4]arenes C-97, C-99, C-107, which are ouabainomymetic high affinity inhibitors of Na+, K(+)-ATPase, on the polarization level of plasmic and mitochondrial membranes of rat uterine smooth muscle cells was investigated. The influence of these compounds on the myocytes characteristic size was studied. By using a confocal microscopy and specific for mitochondrial MitoTracker Orange CM-H2TMRos dye it was proved that the potential-sensitive fluorescent probe DiOC6(3) interacts with mitochondria. Artificial potential collapse of plasmic membrane in this case was modeled by myocytes preincubation with ouabain (1 mM). Further experiments performed using the method of flow cytometry with DiOC6(3) have shown that the compounds C-97, C-99 and C-107 at concentration 50-100 nM caused depolarization of the plasma membrane (at the level of 30% relative to control values) in conditions of artificial collapse of mitochondrial potential by myocytes preincubation in the presence of 5 mM of sodium azide. Under artificial sarcolemma depolarization by ouabain, calixarenes C-97, C-99 and C-107 at 100 nM concentrations caused a transient increase of mitochondrial membrane potential, that is 40% of the control level and lasted about 5 minutes. Calixarenes C-99 and C-107 caused a significant increase in fluorescence of myocytes in these conditions, which was confirmed by confocal microscopy too. It was proved by photon correlation spectroscopy method that the C-99 and C-107 caused an increase of characteristic size of myocytes.

  20. Calcium Sensitization Mechanisms in Gastrointestinal Smooth Muscles

    PubMed Central

    Perrino, Brian A

    2016-01-01

    An increase in intracellular Ca2+ is the primary trigger of contraction of gastrointestinal (GI) smooth muscles. However, increasing the Ca2+ sensitivity of the myofilaments by elevating myosin light chain phosphorylation also plays an essential role. Inhibiting myosin light chain phosphatase activity with protein kinase C-potentiated phosphatase inhibitor protein-17 kDa (CPI-17) and myosin phosphatase targeting subunit 1 (MYPT1) phosphorylation is considered to be the primary mechanism underlying myofilament Ca2+ sensitization. The relative importance of Ca2+ sensitization mechanisms to the diverse patterns of GI motility is likely related to the varied functional roles of GI smooth muscles. Increases in CPI-17 and MYPT1 phosphorylation in response to agonist stimulation regulate myosin light chain phosphatase activity in phasic, tonic, and sphincteric GI smooth muscles. Recent evidence suggests that MYPT1 phosphorylation may also contribute to force generation by reorganization of the actin cytoskeleton. The mechanisms responsible for maintaining constitutive CPI-17 and MYPT1 phosphorylation in GI smooth muscles are still largely unknown. The characteristics of the cell-types comprising the neuroeffector junction lead to fundamental differences between the effects of exogenous agonists and endogenous neurotransmitters on Ca2+ sensitization mechanisms. The contribution of various cell-types within the tunica muscularis to the motor responses of GI organs to neurotransmission must be considered when determining the mechanisms by which Ca2+ sensitization pathways are activated. The signaling pathways regulating Ca2+ sensitization may provide novel therapeutic strategies for controlling GI motility. This article will provide an overview of the current understanding of the biochemical basis for the regulation of Ca2+ sensitization, while also discussing the functional importance to different smooth muscles of the GI tract. PMID:26701920

  1. Engineering Rhodosporidium toruloides with a membrane transporter facilitates production and separation of carotenoids and lipids in a bi-phasic culture.

    PubMed

    Lee, Jaslyn J L; Chen, Liwei; Cao, Bin; Chen, Wei Ning

    2016-01-01

    The oleaginous yeast Rhodosporidium toruloides has great biotechnological potential. It accumulates a high amount of lipids which can be used for biofuels and also produces carotenoids which are valuable in the food and pharmaceutical industry. However, the location of these two hydrophobic products in the cell membrane prohibits its efficient harvesting and separation. Here, the transporter Pdr10 was engineered into R. toruloides and cultured in two-phase media containing oil. This enabled the production and in situ export of carotenoids into the oil and concurrent separation from intracellular lipids in the cells. When Pdr10 strain was cultured in the two-phase media, carotenoids and fatty acids yield increased from 1.9 to 2.9 μg/mg and 0.07 to 0.09 mg/mg, respectively. A total of 1.8 μg/mg carotenoids was exported by Pdr10 strain, as compared to 0.3 μg/mg in the wild type. In the Pdr10 strain, the composition of carotenoids and fatty acid it produced also changed. Torulene became the major carotene produced instead of torularhodin. Also, the unsaturated fatty acid C18:2 became the dominant fatty acid produced instead of the saturated C16:0, which was similar to the grape seed oil used in the two-phase media. This indicated that oil was being consumed by the cells, which was supported by the increased intracellular glycerol levels detected by gas chromatography-mass spectrometry (GC-MS). Our approach represents an easy and greener extraction method which could serve to increase the yield and facilitate separation of carotenoids and fatty acids.

  2. An Improved Model of Heat-Induced Hyperalgesia—Repetitive Phasic Heat Pain Causing Primary Hyperalgesia to Heat and Secondary Hyperalgesia to Pinprick and Light Touch

    PubMed Central

    Henrich, Florian; Magerl, Walter; May, Arne

    2014-01-01

    This study tested a modified experimental model of heat-induced hyperalgesia, which improves the efficacy to induce primary and secondary hyperalgesia and the efficacy-to-safety ratio reducing the risk of tissue damage seen in other heat pain models. Quantitative sensory testing was done in eighteen healthy volunteers before and after repetitive heat pain stimuli (60 stimuli of 48°C for 6 s) to assess the impact of repetitive heat on somatosensory function in conditioned skin (primary hyperalgesia area) and in adjacent skin (secondary hyperalgesia area) as compared to an unconditioned mirror image control site. Additionally, areas of flare and secondary hyperalgesia were mapped, and time course of hyperalgesia determined. After repetitive heat pain conditioning we found significant primary hyperalgesia to heat, and primary and secondary hyperalgesia to pinprick and to light touch (dynamic mechanical allodynia). Acetaminophen (800 mg) reduced pain to heat or pinpricks only marginally by 11% and 8%, respectively (n.s.), and had no effect on heat hyperalgesia. In contrast, the areas of flare (−31%) and in particular of secondary hyperalgesia (−59%) as well as the magnitude of hyperalgesia (−59%) were significantly reduced (all p<0.001). Thus, repetitive heat pain induces significant peripheral sensitization (primary hyperalgesia to heat) and central sensitization (punctate hyperalgesia and dynamic mechanical allodynia). These findings are relevant to further studies using this model of experimental heat pain as it combines pronounced peripheral and central sensitization, which makes a convenient model for combined pharmacological testing of analgesia and anti-hyperalgesia mechanisms related to thermal and mechanical input. PMID:24911787

  3. Cannabinoid transmission in the prefrontal cortex bi-phasically controls emotional memory formation via functional interactions with the ventral tegmental area.

    PubMed

    Draycott, Brittany; Loureiro, Michael; Ahmad, Tasha; Tan, Huibing; Zunder, Jordan; Laviolette, Steven R

    2014-09-24

    Disturbances in cortical cannabinoid CB1 receptor signaling are well established correlates of various neuropsychiatric disorders, including depression and schizophrenia. Importantly, the ability of cannabinoid transmission to modulate emotional processing is functionally linked to interactions with subcortical DA systems. While considerable evidence demonstrates that CB1 receptor-mediated modulation of emotional processing and related behaviors follows a biphasic functional curve, little is known regarding how CB1 signaling within cortical networks may interact with subcortical DAergic systems involved in emotional behavior regulation. Using a combination of in vivo electrophysiological recordings and behavioral pharmacology in rats, we investigated the relationship between mPFC cannabinoid transmission, fear memory formation, and subcortical DA neuron activity patterns. We report that direct intra-mPFC CB1 activation biphasically modulates spontaneous, subcortical VTA DA neuron activity in a dose-dependent fashion; while lower doses of a CB1 receptor agonist, WIN 55,212-2, significantly increased spontaneous firing and bursting rates of VTA DA neurons, higher doses strongly inhibited spontaneous DA neuron activity. Remarkably, this same dose-related functional difference was observed with the regulation of fear-related emotional memory formation. Thus, lower levels of CB1 activation potentiated the emotional salience of normally subthreshold fear memory, whereas higher levels completely blocked fear memory acquisition. Furthermore, while the potentiation of subthreshold fear memory salience was blocked by DA receptor antagonism, CB1-mediated blunting of suprathreshold fear memory was rescued by intra-VTA administration of a GABAB receptor antagonist, demonstrating that reversal of GABAergic inhibitory mechanisms in the VTA can reverse the inhibitory influence of intra-PFC CB1 transmission on mesolimbic DA activity. PMID:25253856

  4. Contributions of the GABAA Receptor α6 Subunit to Phasic and Tonic Inhibition Revealed by a Naturally Occurring Polymorphism in the α6 Gene

    PubMed Central

    Santhakumar, Vijayalakshmi; Hanchar, H. Jacob; Wallner, Martin; Olsen, Richard W.; Otis, Thomas S.

    2007-01-01

    GABAA receptors (GABARs) are heteromultimeric proteins composed of five subunits. The specific subunit composition determines critical properties of a GABAR such as pharmacological sensitivities and whether the receptor contributes to synaptic or extrasynaptic forms of inhibition. Classically, synaptic but not extrasynaptic GABARs are thought to respond to benzodiazepines, whereas the reverse has been suggested for ethanol. To examine the effects of subunit composition on GABAR function in situ, we took advantage of two naturally occurring alleles of the rat gene for GABAR subunit α6 (Gabra6100R and Gabra6100Q). Depending on their subunit partners, these two variants of α6 can lead to differential sensitivities to benzodiazepines and ethanol. An examination of synaptic and extrasynaptic GABA-mediated currents in cerebellar granule cells from Gabra6100R/100R and Gabra6100Q/100Q rats uncovered marked allele-dependent differences in benzodiazepine sensitivity. Unexpectedly, we found that the benzodiazepines flunitrazepam and diazepam enhanced extrasynaptic inhibition mediated by δ subunit-containing GABARs in Gabra6100Q/100Q rats. Complementary experiments on recombinant GABARs confirmed that, at subsaturating [GABA], flunitrazepam potentiates α6/δ subunit-containing GABARs. Based on data and a simple theoretical analysis, we estimate that the average extrasynaptic [GABA] is ∼160 nm in perfused slices. These results (1) demonstrate contributions of α6 subunits to both synaptic and extrasynaptic GABA responses, (2) establish that δ subunit-containing GABARs are benzodiazepine sensitive at subsaturating [GABA] and, (3) provide an empirical estimate of extrasynaptic [GABA] in slices. PMID:16554486

  5. The effects of Ginseng Java root extract on uterine contractility in nonpregnant rats

    PubMed Central

    Sukwan, Catthareeya; Wray, Susan; Kupittayanant, Sajeera

    2014-01-01

    Abstract Ginseng Java or Talinum paniculatum (Jacq.) Geartn has long been used in herbal recipes because of its various therapeutic properties. Ginseng Java is believed to be beneficial to the female reproductive system by inducing lactation and restoring uterine functions after the postpartum period. There are, however, no scientific data on verifying the effects on the uterus to support its therapeutic relevance. Therefore, the purpose of this study was to investigate the effects of Ginseng Java root extract and its possible mechanism(s) of action on uterine contractility. Female virgin rats were humanely killed by CO2 asphyxia and uteri removed. Isometric force was measured in strips of longitudinal myometrium. The effects of Ginseng Java root extract at its IC50 concentration (0.23 mg/mL) on spontaneous, oxytocin‐induced (10 nmol/L), and depolarized (KCl 40 mmol/L) contraction were investigated. After establishing regular phasic contractions, the application of Java root extract significantly inhibited spontaneous uterine contractility (n =5). The extract also significantly inhibited the contraction induced by high KCl solution (n =5) and oxytocin (n =5). The extract also inhibited oxytocin‐induced contraction in the absence of external Ca entry (n =7) and the tonic force induced by oxytocin in the presence of high KCl solution. Taken together, the data demonstrate a potent and consistent ability of extract from Ginseng Java root to reduce myometrial contractility. The tocolytic effects were demonstrated on both spontaneous and agonist‐induced contractions. The fact that force was inhibited in depolarized conditions suggests that the possible mechanisms may be blockade of Ca influx via L‐type Ca channels. The data in Ca‐free solutions suggest that the extract also reduces IP3‐induced Ca release from the internal store. These tocolytic effects do not support the use of ginseng to help with postpartum contractility, but instead suggest it may be

  6. Endothelin induces two types of contractions of rat uterus: phasic contractions by way of voltage-dependent calcium channels and developing contractions through a second type of calcium channels

    SciTech Connect

    Kozuka, M.; Ito, T.; Hirose, S.; Takahashi, K.; Hagiwara, H.

    1989-02-28

    Effects of endothelin on nonvascular smooth muscle have been examined using rat uterine horns and two modes of endothelin action have been revealed. Endothelin (0.3 nM) caused rhythmic contractions of isolated uterus in the presence of extracellular calcium. The rhythmic contractions were completely inhibited by calcium channel antagonists. These characteristics of endothelin-induced contractions were very similar to those induced by oxytocin. Binding assays using /sup 125/I-endothelin showed that endothelin and the calcium channel blockers did not compete for the binding sites. However, endothelin was unique in that it caused, in addition to rhythmic contractions, a slowly developing monophasic contraction that was insensitive to calcium channel blockers. This developing contraction became dominant at higher concentrations of endothelin and was also calcium dependent.

  7. Diagnostic Accuracy of MRI, DWI MRI, FDG-PET/CT and FEC PET/CT in the Detection of Lymph Node Metastases in Surgically Staged Endometrial and Cervical Carcinoma

    ClinicalTrials.gov

    2016-01-21

    Surgically Staged Endometrial and Cervical Carcinoma; Cervical Cancer: Invasive Disease, FIGO Stage 1B1 or Higher; Endometrial Cancer:; Stage 1A With Myometrial Invasion or Any Higher Stage and Grade 3; Stage 1A With Myometrial Invasion or Any Other Higher Stage and Serous Papillary or Clear Cell Sub-types; Stage II Disease or Above and Any Histology Grade

  8. Generation of myometrium-specific Bmal1 knockout mice for parturition analysis.

    PubMed

    Ratajczak, Christine K; Asada, Minoru; Allen, Gregg C; McMahon, Douglas G; Muglia, Lisa M; Smith, Donté; Bhattacharyya, Sandip; Muglia, Louis J

    2012-01-01

    Human and rodent studies indicate a role for circadian rhythmicity and associated clock gene expression in supporting normal parturition. The importance of clock gene expression in tissues besides the suprachiasmatic nucleus is emerging. Here, a Bmal1 conditional knockout mouse line and a novel Cre transgenic mouse line were used to examine the role of myometrial Bmal1 in parturition. Ninety-two percent (22/24) of control females but only 64% (14/22) of females with disrupted myometrial Bmal1 completed parturition during the expected time window of 5p.m. on Day 19 through to 9a.m. on Day 19.5 of gestation. However, neither serum progesterone levels nor uterine transcript expression of the contractile-associated proteins Connexin43 and Oxytocin receptor differed between females with disrupted myometrial Bmal1 and controls during late gestation. The data indicate a role for myometrial Bmal1 in maintaining normal time of day of parturition.

  9. Spiral artery remodeling and trophoblast invasion in preeclampsia and fetal growth restriction: relationship to clinical outcome.

    PubMed

    Lyall, Fiona; Robson, Stephen C; Bulmer, Judith N

    2013-12-01

    Failure to transform uteroplacental spiral arteries is thought to underpin disorders of pregnancy, including preeclampsia and fetal growth restriction (FGR). In this study, spiral artery remodeling and extravillous-cytotrophoblast were examined in placental bed biopsies from normal pregnancy (n = 25), preeclampsia (n = 22), and severe FGR (n = 10) and then compared with clinical parameters. Biopsies were immunostained to determine vessel wall integrity, extravillous-cytotrophoblast location/density, periarterial fibrinoid, and endothelium. Muscle disruption was reduced in myometrial spiral arteries in preeclampsia (P = 0.0001) and FGR (P = 0.0001) compared with controls. Myometrial vessels from cases with birth weight <5th percentile (P<0.001), abnormal uterine Doppler (P<0.01), abnormal umbilical artery Doppler (P<0.001), and preterm delivery (P<0.001) had less muscle destruction compared with >5th percentile. Fewer extravillous-cytotrophoblast surrounded both decidual and myometrial vessels in the normal group and preeclampsia group compared with the FGR group (P = 0.001). For myometrial vessels, the normal group contained more intramural extravillous-cytotrophoblast than in preeclampsia (P = 0.015). Decidual vessels in the FGR group had less fibrinoid deposition compared with controls (P = 0.013). For myometrial vessels, less fibrinoid was deposited in both the preeclampsia group (P = 0.0001) and the FGR group (P = 0.01) when compared with controls, and less fibrinoid was deposited in the preeclampsia group when compared with FGR group (P<0.001). Myometrial vessels obtained from birth weights <5th percentile had less periarterial fibrinoid than those with >5th percentile (P<0.02). A major defect in myometrial spiral artery remodeling occurs in preeclampsia and FGR that is linked to clinical parameters. Interstitial extravillous-cytotrophoblast is not reduced in preeclampsia but is increased in FGR. PMID:24060885

  10. Agonist-sensitive calcium pool in the pancreatic acinar cell. II. Characterization of reloading

    SciTech Connect

    Muallem, S.; Schoeffield, M.S.; Fimmel, C.J.; Pandol, S.J.

    1988-08-01

    45Ca2+ fluxes and free cytosolic Ca2+ measurements in guinea pig pancreatic acini indicated that after agonist stimulation and the release of Ca2+ from the agonist-sensitive pool at least part of the Ca2+ is extruded from the cell, resulting in 45Ca2+ efflux. In the continued presence of agonist, the pool remains permeable to Ca2+ but partially refills with Ca2+. This reloading is dependent on the concentration of extracellular Ca2+. In the absence of extracellular Ca2+, the pool is completely depleted of Ca2+. However, with increasing concentrations of CaCl2 in the incubation solution (from 0.5 to 2.0 mM) there is increasing repletion of the pool with Ca2+ during agonist stimulation. With termination of agonist stimulation, the Ca2+ permeability of the agonist-sensitive pool is rapidly reduced to that measured in the unstimulated cell. As a result, the Ca2+ incorporated into the pool during the stimulation period is rapidly trapped within the pool and exchanges poorly with medium Ca2+. Subsequently, the pool completely refills with Ca2+. The rate of Ca2+ reloading at the termination of agonist stimulation is slower than the conversion of the pool to the impermeable state. In incubation media containing 1.3 mM CaCl2, the half-time for reloading at the termination of stimulation is 5 min. These observations demonstrate the characteristics of Ca2+ reloading of the agonist-sensitive pool both during stimulation and at the termination of stimulation.

  11. Alkaline phosphatase relieves desensitization of adenylate cyclase-coupled beta-adrenergic receptors in avian erythrocyte membranes

    SciTech Connect

    Stadel, J.M.; Rebar, R.; Crooke, S.T.

    1987-05-01

    Desensitization of adenylate cyclase-coupled ..beta..-adrenergic receptors in avian erythrocytes results in 40-65% decrease in agonist-stimulated adenylate cyclase activity and correlates with increased phosphorylation of ..beta..-adrenergic receptors. To assess the role of phosphorylation in desensitization, membranes from isoproterenol- and cAMP-desensitized turkey erythrocytes were incubated with alkaline phosphatase for 30 min at 37/sup 0/C, pH = 8.0. In both cases alkaline phosphatase treatment significantly reduced desensitization of agonist-stimulated adenylate cyclase activity by 40-60%. Similar results were obtained following alkaline phosphatase treatment of membranes from isoproterenol- and cAMP-desensitized duck erythrocytes. In addition, alkaline phosphatase treatment of membranes from duck erythrocytes desensitized with phorbol 12-mystrate 13-acetate returned adenylate cyclase activity to near control values. In all experiments inclusion of 20 mM NaPO/sub 4/ to inhibit alkaline phosphatase during treatment of membranes blocked the enzyme's effect on agonist-stimulated adenylate cyclase activity. These results demonstrate a role for phosphorylation in desensitization of adenylate cyclase-coupled ..beta..-adrenergic receptors in avian erythrocytes.

  12. Terms, definitions and measurements to describe sonographic features of myometrium and uterine masses: a consensus opinion from the Morphological Uterus Sonographic Assessment (MUSA) group.

    PubMed

    Van den Bosch, T; Dueholm, M; Leone, F P G; Valentin, L; Rasmussen, C K; Votino, A; Van Schoubroeck, D; Landolfo, C; Installé, A J F; Guerriero, S; Exacoustos, C; Gordts, S; Benacerraf, B; D'Hooghe, T; De Moor, B; Brölmann, H; Goldstein, S; Epstein, E; Bourne, T; Timmerman, D

    2015-09-01

    The MUSA (Morphological Uterus Sonographic Assessment) statement is a consensus statement on terms, definitions and measurements that may be used to describe and report the sonographic features of the myometrium using gray-scale sonography, color/power Doppler and three-dimensional ultrasound imaging. The terms and definitions described may form the basis for prospective studies to predict the risk of different myometrial pathologies, based on their ultrasound appearance, and thus should be relevant for the clinician in daily practice and for clinical research. The sonographic features and use of terminology for describing the two most common myometrial lesions (fibroids and adenomyosis) and uterine smooth muscle tumors are presented.

  13. Task completion report for update FXFILL

    SciTech Connect

    Steinke, R.G.

    1997-09-02

    The FILL component in TRAC-P defines a phasic-velocities boundary condition or total-mass-flow boundary condition. FILL option IFTY = 10 defines the total-mass flow and its composition for flow donoring from the FILL to its adjacent component by signal variables and/or control blocks. For flow from the adjacent component to the FILL component, the phasic densities of the adjacent-component cell need to be upstream donored by the IFTY = 10 option total-mass flow. Instead, the FILL-cell phasic densities are being downstream donored incorrectly by the IFTY = 10 option total-mass flow in determining the FILL-junction phasic velocities. Using the wrong donored phasic densities caused the phasic velocities determined from the total-mass flow to be evaluated incorrectly. Five errors related to phasic-density donoring into a FILL- or BREAK-component cell are corrected by update FXFILL. Seven versions of a new test problem test these corrections and show that the errors of trouble reports 189 and 190 no longer exist in TRAC-P.

  14. Effect of environmental pollutants on oxytocin synthesis and secretion from corpus luteum and on contractions of uterus from pregnant cows

    SciTech Connect

    Mlynarczuk, Jaroslaw; Wrobel, Michal H.; Kotwica, Jan

    2010-09-15

    Chloro-organic compounds are persistent environmental pollutants and affect many reproductive processes. Oxytocin (OT) synthesized in luteal cells is a local regulator of ovarian activity and uterine contractions. Therefore the effect of xenobiotics on the OT prohormone synthesis, secretion of OT and progesterone (P4) from luteal cells and on myometrial contractions during early pregnancy in cows was investigated. Luteal cells and myometrial strips from a cow at early pregnancy were treated with polychlorinated biphenyl 77 (PCB 77), dichlorodiphenyltrichloroethane (DDT), dichlorodiphenyldichloroethylene (DDE) and hexachlorocyclohexane (HCH) (1 or 10 ng/ml). The mRNA expression of neurophysin-I/oxytocin (NP-I/OT) and peptidyl-glycine-{alpha}-amidating mono-oxygenase (PGA) and concentration of OT and P4 were determined by RT-PCR and EIA, respectively. Moreover, the effect of xenobiotics given with P4 (12 ng/ml) on the basal and OT (10{sup -7} M) stimulated contractions of myometrial strips was studied. Xenobiotics increased (P < 0.05) OT secretion but DDE only stimulated P4 secretion. The ratio of P4 to OT in culture medium was decreased by all xenobiotics during 9-12 weeks of pregnancy. All xenobiotics, except HCH, increased (P < 0.05) mRNA expression of NP-I/OT during all stages of pregnancy and all treatments decreased (P < 0.05) expression of mRNA for PGA during 9-12 weeks of pregnancy. Myometrial strips were relaxed (P < 0.01) after pre-incubation with P4, while each of the xenobiotics jointly with P4 increased (P < 0.01) myometrial contractions. In conclusion, the xenobiotics used increased both expression of mRNA for genes involved in OT synthesis and secretion of OT from luteal cells. This decreases the ratio of P4 to OT and presumably, in this manner, the chloro-organic compounds can influence uterine contractions and enhance risk of abortions in pregnant females.

  15. Neural signals of extinction in the inhibitory microcircuit of the ventral midbrain.

    PubMed

    Pan, Wei-Xing; Brown, Jennifer; Dudman, Joshua Tate

    2013-01-01

    Midbrain dopaminergic (DA) neurons are thought to guide learning via phasic elevations of firing in response to reward predicting stimuli. The mechanism for these signals remains unclear. Using extracellular recording during associative learning, we found that inhibitory neurons in the ventral midbrain of mice responded to salient auditory stimuli with a burst of activity that occurred before the onset of the phasic response of DA neurons. This population of inhibitory neurons exhibited enhanced responses during extinction and was anticorrelated with the phasic response of simultaneously recorded DA neurons. Optogenetic stimulation revealed that this population was, in part, derived from inhibitory projection neurons of the substantia nigra that provide a robust monosynaptic inhibition of DA neurons. Thus, our results elaborate on the dynamic upstream circuits that shape the phasic activity of DA neurons and suggest that the inhibitory microcircuit of the midbrain is critical for new learning in extinction.

  16. Rapid infrared heating of a surface

    DOEpatents

    Sikka, Vinod K.; Blue, Craig A.; Ohriner, Evan Keith

    2001-01-01

    High energy flux infrared heaters are used to treat an object having a surface section and a base section such that a desired characteristic of the surface section is physically, chemically, or phasically changed while the base section remains unchanged.

  17. Rapid infrared heating of a surface

    DOEpatents

    Sikka, Vinod K.; Blue, Craig A.; Ohriner, Evan Keith

    2002-01-01

    High energy flux infrared heaters are used to treat an object having a surface section and a base section such that a desired characteristic of the surface section is physically, chemically, or phasically changed while the base section remains unchanged.

  18. Rapid infrared heating of a surface

    DOEpatents

    Sikka, Vinod K.; Blue, Craig A.; Ohriner, Evan Keith

    2003-12-23

    High energy flux infrared heaters are used to treat an object having a surface section and a base section such that a desired characteristic of the surface section is physically, chemically, or phasically changed while the base section remains unchanged.

  19. Interactive effect of beta-adrenergic stimulation and mechanical stretch on low-frequency oscillations of ventricular action potential duration in humans.

    PubMed

    Pueyo, Esther; Orini, Michele; Rodríguez, José F; Taggart, Peter

    2016-08-01

    Ventricular repolarization dynamics are crucial to arrhythmogenesis. Low-frequency oscillations of repolarization have recently been reported in humans and the magnitude of these oscillations proposed to be a strong predictor of sudden cardiac death. Available evidence suggests a role of the sympathetic nervous system. We have used biophysically detailed models integrating ventricular electrophysiology, calcium dynamics, mechanics and β-adrenergic signaling to investigate the underlying mechanisms. The main results were: (1) Phasic beta-adrenergic stimulation (β-AS) at a Mayer wave frequency between 0.03 and 0.15Hz resulted in a gradual decrease of action potential (AP) duration (APD) with concomitant small APD oscillations. (2) After 3-4minutes of phasic β-AS, the mean APD adapted and oscillations of APD became apparent. (3) Phasic changes in haemodynamic loading at the same Mayer wave frequency (a known accompaniment of enhanced sympathetic nerve activity), simulated as variations in the sarcomere length, also induced APD oscillations. (4) The effect of phasic β-AS and haemodynamic loading on the magnitude of APD oscillations was synergistic. (5) The presence of calcium overload and reduced repolarization reserve further enhanced the magnitude of APD oscillations and was accompanied by afterdepolarizations and/or spontaneous APs. In conclusion, low-frequency oscillations of repolarization recently reported in humans were induced by phasic β-AS and phasic mechanical loading, which acted synergistically, and were greatly enhanced by disease-associated conditions, leading to arrhythmogenic events. PMID:27178727

  20. BANK1 Regulates IgG Production in a Lupus Model by Controlling TLR7-Dependent STAT1 Activation

    PubMed Central

    Iida, Ryuji; Bagavant, Harini; Alarcón-Riquelme, Marta E.

    2016-01-01

    The purpose of our study was to investigate the effects of the adaptor Bank1 in TLR7 signaling using the B6.Sle1.yaa mouse, a lupus model that develops disease through exacerbated TLR7 expression. Crosses of B6.Sle1.yaa with Bank1-/- mice maintained several B and myeloid cell phenotypes close to normal wild-type levels. Most striking was the reduction in total serum IgG antibodies, but not of IgM, and reduced serum levels of autoantibodies, IL-6, and BAFF. Bank1 deficiency did modify numbers of MZ B cells and total B cell numbers, as well as expression of CXCR4 by follicular helper T cells. Other T cell changes were not observed. Bank1 deficiency did not modify numbers of germinal center B cells or plasma cells or clinical disease outcomes. Purified B cells from Bank1 deficient mice had strongly reduced Ifnb, Ifna4, Irf7, Aicda and Stat1 gene expression following TLR7 agonist stimulation. Interestingly, phosphorylation of Tyr701, but not of Ser727 of STAT1, was impaired in splenic B cells from B6.Sle1.yaa.Bank1-/- mice, as was the nuclear translocation of IRF7 in response to TLR7 agonist stimulation. Further, Bank1 deficiency in B6.Sle1.yaa mice reduced the production of IgG2c after in vitro TLR7 agonist stimulation. Our results demonstrate that Bank1 controls TLR7-mediated type I interferon production. Combined with the control of the nuclear translocation of IRF7, the modulation of STAT1 transcription and phosphorylation, Bank1 contributes to IgG production during development of autoimmune disease. PMID:27228057

  1. G protein-coupled receptor kinase-2 is a novel regulator of collagen synthesis in adult human cardiac fibroblasts.

    PubMed

    D'Souza, Karen M; Malhotra, Ricky; Philip, Jennifer L; Staron, Michelle L; Theccanat, Tiju; Jeevanandam, Valluvan; Akhter, Shahab A

    2011-04-29

    Cardiac fibroblasts (CF) make up 60-70% of the total cell number in the heart and play a critical role in regulating normal myocardial function and in adverse remodeling following myocardial infarction and the transition to heart failure. Recent studies have shown that increased intracellular cAMP can inhibit CF transformation and collagen synthesis in adult rat CF; however, mechanisms by which cAMP production is regulated in CF have not been elucidated. We investigated the potential role of G protein-coupled receptor kinase-2 (GRK2) in modulating collagen synthesis by adult human CF isolated from normal and failing left ventricles. Baseline collagen synthesis was elevated in failing CF and was not inhibited by β-agonist stimulation in contrast to normal controls. β-adrenergic receptor (β-AR) signaling was markedly uncoupled in the failing CF, and expression and activity of GRK2 were increased 3-fold. Overexpression of GRK2 in normal CF recapitulated a heart failure phenotype with minimal inhibition of collagen synthesis following β-agonist stimulation. In contrast, knockdown of GRK2 expression in normal CF enhanced cAMP production and led to greater β-agonist-mediated inhibition of basal and TGFβ-stimulated collagen synthesis versus control. Inhibition of GRK2 activity in failing CF by expression of the GRK2 inhibitor, GRK2ct, or siRNA-mediated knockdown restored β-agonist-stimulated inhibition of collagen synthesis and decreased collagen synthesis in response to TGFβ stimulation. GRK2 appears to play a significant role in regulating collagen synthesis in adult human CF, and increased activity of this kinase may be an important mechanism of maladaptive ventricular remodeling as mediated by cardiac fibroblasts.

  2. mu-Opioid receptor-stimulated guanosine-5'-O-(gamma-thio)-triphosphate binding in rat thalamus and cultured cell lines: signal transduction mechanisms underlying agonist efficacy.

    PubMed

    Selley, D E; Sim, L J; Xiao, R; Liu, Q; Childers, S R

    1997-01-01

    G protein activation by different mu-selective opioid agonists was examined in rat thalamus, SK-N-SH cells, and mu-opioid receptor-transfected mMOR-CHO cells using agonist-stimulated guanosine-5'-O-(gamma-thio)-triphosphate ([35S]GTP gamma S) binding to membranes in the presence of excess GDP. [D-Ala2, N-MePhe4, Gly5-ol]Enkephalin (DAMGO) was the most efficacious agonist in rat thalamus and SK-N-SH cells, followed by (in rank order) fentanyl = morphine > > buprenorphine. In mMOR-CHO cells expressing a high density of mu receptors, no differences were observed among DAMGO, morphine or fentanyl, but these agonists were more efficacious than buprenorphine, which was more efficacious than levallorphan. In all three systems, efficacy differences were magnified by increasing GDP concentrations, indicating that the activity state of G proteins can affect agonist efficacy. Scatchard analysis of net agon stimulated [35S]GTP gamma S binding revealed two major components responsible for agonist efficacy differences. First, differences in the KD values of agonist-stimulated [35S]GTP gamma S binding between high efficacy agonists (DAMGO, fentanyl, and morphine) and classic partial agonists (buprenorphine and levallorphan) were observed in all three systems. Second, differences in the Bmax value of agonist-stimulated [35S]GTP gamma S binding were observed between DAMGO and morphine or fentanyl in rat thalamus and SK-N-SH cells and between the high efficacy agonists and buprenorphine or levallorphan in all three systems. These results suggest that mu-opioid agonist efficacy is determined by the magnitude of the receptor-mediated affinity shift in the binding of GTP (or[35S]GTP gamma S) versus GDP to the G protein and by the number of G proteins activated per occupied receptor.

  3. The interplay between plasma membrane and endoplasmic reticulum Ca(2+)ATPases in agonist-induced temporal Ca(2+) dynamics.

    PubMed

    Cicek, Figen Amber; Ozgur, Ekin Ozge; Ozgur, Erol; Ugur, Mehmet

    2014-12-01

    A change in the intracellular free Ca(2+) concentration ([Ca(2+)]i) functions as a transmitter for signal transduction and shows a broad temporal pattern. Even genetically homogeneous cell types show different Ca(2+) response patterns under permanent agonist stimulation. In Ca(2+) signaling, the dynamics of the Ca(2+) release from the Ca(2+) channels during continuous agonist stimulation and the simultaneous effect of the pumps are unclear. In this study, the dynamic interaction of the Ca(2+) ATPases in the plasma membrane (PMCA) and the endoplasmic reticulum membrane (SERCA) during continuous ACh stimulation is monitored using Fluo-3 and Fura-2 loaded HEK 293 cells. We characterize Ca(2+) release patterns at the sub-maximal and maximal stimulation doses in the absence of extracellular Ca(2+). We analyze the responses regarding their types, oscillation frequency and response times. La(3+) (PMCA blocker) do not change the frequency and time courses in sub-maximal ACh treatment, while with the maximal stimulation oscillation frequency increase as oscillations superimpose on robust release, and response time of [Ca(2+)]i is elongated. A similar effect of La(3+) is observed in quantal Ca(2+) release phenomenon. In the presence of CPA, a SERCA blocker, oscillations are completely abolished, but response time does not change. We also observe that during continuous receptor stimulation, Ca(2+) release do not cease. These data may suggest that Ca(2+) release continues during agonist stimulation, but SERCA and PMCA form a new steady state and return [Ca(2+)]i to its physiological concentration. PMID:25331516

  4. Cannabinoid Receptor–Interacting Protein 1a Modulates CB1 Receptor Signaling and Regulation

    PubMed Central

    Smith, Tricia H.; Blume, Lawrence C.; Straiker, Alex; Cox, Jordan O.; David, Bethany G.; McVoy, Julie R. Secor; Sayers, Katherine W.; Poklis, Justin L.; Abdullah, Rehab A.; Egertová, Michaela; Chen, Ching-Kang; Mackie, Ken; Elphick, Maurice R.; Howlett, Allyn C.

    2015-01-01

    Cannabinoid CB1 receptors (CB1Rs) mediate the presynaptic effects of endocannabinoids in the central nervous system (CNS) and most behavioral effects of exogenous cannabinoids. Cannabinoid receptor–interacting protein 1a (CRIP1a) binds to the CB1R C-terminus and can attenuate constitutive CB1R-mediated inhibition of Ca2+ channel activity. We now demonstrate cellular colocalization of CRIP1a at neuronal elements in the CNS and show that CRIP1a inhibits both constitutive and agonist-stimulated CB1R-mediated guanine nucleotide–binding regulatory protein (G-protein) activity. Stable overexpression of CRIP1a in human embryonic kidney (HEK)-293 cells stably expressing CB1Rs (CB1-HEK), or in N18TG2 cells endogenously expressing CB1Rs, decreased CB1R-mediated G-protein activation (measured by agonist-stimulated [35S]GTPγS (guanylyl-5′-[O-thio]-triphosphate) binding) in both cell lines and attenuated inverse agonism by rimonabant in CB1-HEK cells. Conversely, small-interfering RNA–mediated knockdown of CRIP1a in N18TG2 cells enhanced CB1R-mediated G-protein activation. These effects were not attributable to differences in CB1R expression or endocannabinoid tone because CB1R levels did not differ between cell lines varying in CRIP1a expression, and endocannabinoid levels were undetectable (CB1-HEK) or unchanged (N18TG2) by CRIP1a overexpression. In CB1-HEK cells, 4-hour pretreatment with cannabinoid agonists downregulated CB1Rs and desensitized agonist-stimulated [35S]GTPγS binding. CRIP1a overexpression attenuated CB1R downregulation without altering CB1R desensitization. Finally, in cultured autaptic hippocampal neurons, CRIP1a overexpression attenuated both depolarization-induced suppression of excitation and inhibition of excitatory synaptic activity induced by exogenous application of cannabinoid but not by adenosine A1 agonists. These results confirm that CRIP1a inhibits constitutive CB1R activity and demonstrate that CRIP1a can also inhibit agonist-stimulated

  5. Cannabinoid receptor-interacting protein 1a modulates CB1 receptor signaling and regulation.

    PubMed

    Smith, Tricia H; Blume, Lawrence C; Straiker, Alex; Cox, Jordan O; David, Bethany G; McVoy, Julie R Secor; Sayers, Katherine W; Poklis, Justin L; Abdullah, Rehab A; Egertová, Michaela; Chen, Ching-Kang; Mackie, Ken; Elphick, Maurice R; Howlett, Allyn C; Selley, Dana E

    2015-04-01

    Cannabinoid CB1 receptors (CB1Rs) mediate the presynaptic effects of endocannabinoids in the central nervous system (CNS) and most behavioral effects of exogenous cannabinoids. Cannabinoid receptor-interacting protein 1a (CRIP1a) binds to the CB1R C-terminus and can attenuate constitutive CB1R-mediated inhibition of Ca(2+) channel activity. We now demonstrate cellular colocalization of CRIP1a at neuronal elements in the CNS and show that CRIP1a inhibits both constitutive and agonist-stimulated CB1R-mediated guanine nucleotide-binding regulatory protein (G-protein) activity. Stable overexpression of CRIP1a in human embryonic kidney (HEK)-293 cells stably expressing CB1Rs (CB1-HEK), or in N18TG2 cells endogenously expressing CB1Rs, decreased CB1R-mediated G-protein activation (measured by agonist-stimulated [(35)S]GTPγS (guanylyl-5'-[O-thio]-triphosphate) binding) in both cell lines and attenuated inverse agonism by rimonabant in CB1-HEK cells. Conversely, small-interfering RNA-mediated knockdown of CRIP1a in N18TG2 cells enhanced CB1R-mediated G-protein activation. These effects were not attributable to differences in CB1R expression or endocannabinoid tone because CB1R levels did not differ between cell lines varying in CRIP1a expression, and endocannabinoid levels were undetectable (CB1-HEK) or unchanged (N18TG2) by CRIP1a overexpression. In CB1-HEK cells, 4-hour pretreatment with cannabinoid agonists downregulated CB1Rs and desensitized agonist-stimulated [(35)S]GTPγS binding. CRIP1a overexpression attenuated CB1R downregulation without altering CB1R desensitization. Finally, in cultured autaptic hippocampal neurons, CRIP1a overexpression attenuated both depolarization-induced suppression of excitation and inhibition of excitatory synaptic activity induced by exogenous application of cannabinoid but not by adenosine A1 agonists. These results confirm that CRIP1a inhibits constitutive CB1R activity and demonstrate that CRIP1a can also inhibit agonist-stimulated

  6. Reactive oxygen species and nitric oxide mediate plasticity of neuronal calcium signaling

    NASA Astrophysics Data System (ADS)

    Yermolaieva, Olena; Brot, Nathan; Weissbach, Herbert; Heinemann, Stefan H.; Hoshi, Toshinori

    2000-01-01

    Reactive oxygen species (ROS) and nitric oxide (NO) are important participants in signal transduction that could provide the cellular basis for activity-dependent regulation of neuronal excitability. In young rat cortical brain slices and undifferentiated PC12 cells, paired application of depolarization/agonist stimulation and oxidation induces long-lasting potentiation of subsequent Ca2+ signaling that is reversed by hypoxia. This potentiation critically depends on NO production and involves cellular ROS utilization. The ability to develop the Ca2+ signal potentiation is regulated by the developmental stage of nerve tissue, decreasing markedly in adult rat cortical neurons and differentiated PC12 cells.

  7. Absence of NMDA receptors in dopamine neurons attenuates dopamine release but not conditioned approach during Pavlovian conditioning.

    PubMed

    Parker, Jones G; Zweifel, Larry S; Clark, Jeremy J; Evans, Scott B; Phillips, Paul E M; Palmiter, Richard D

    2010-07-27

    During Pavlovian conditioning, phasic dopamine (DA) responses emerge to reward-predictive stimuli as the subject learns to anticipate reward delivery. This observation has led to the hypothesis that phasic dopamine signaling is important for learning. To assess the ability of mice to develop anticipatory behavior and to characterize the contribution of dopamine, we used a food-reinforced Pavlovian conditioning paradigm. As mice learned the cue-reward association, they increased their head entries to the food receptacle in a pattern that was consistent with conditioned anticipatory behavior. D1-receptor knockout (D1R-KO) mice had impaired acquisition, and systemic administration of a D1R antagonist blocked both the acquisition and expression of conditioned approach in wild-type mice. To assess the specific contribution of phasic dopamine transmission, we tested mice lacking NMDA-type glutamate receptors (NMDARs) exclusively in dopamine neurons (NR1-KO mice). Surprisingly, NR1-KO mice learned at the same rate as their littermate controls. To evaluate the contribution of NMDARs to phasic dopamine release in this paradigm, we performed fast-scan cyclic voltammetry in the nucleus accumbens of awake mice. Despite having significantly attenuated phasic dopamine release following reward delivery, KO mice developed cue-evoked dopamine release at the same rate as controls. We conclude that NMDARs in dopamine neurons enhance but are not critical for phasic dopamine release to behaviorally relevant stimuli; furthermore, their contribution to phasic dopamine signaling is not necessary for the development of cue-evoked dopamine or anticipatory activity in a D1R-dependent Pavlovian conditioning paradigm.

  8. The Effects of Electrical and Optical Stimulation of Midbrain Dopaminergic Neurons on Rat 50-kHz Ultrasonic Vocalizations

    PubMed Central

    Scardochio, Tina; Trujillo-Pisanty, Ivan; Conover, Kent; Shizgal, Peter; Clarke, Paul B. S.

    2015-01-01

    Rationale: Adult rats emit ultrasonic vocalizations (USVs) at around 50-kHz; these commonly occur in contexts that putatively engender positive affect. While several reports indicate that dopaminergic (DAergic) transmission plays a role in the emission of 50-kHz calls, the pharmacological evidence is mixed. Different modes of dopamine (DA) release (i.e., tonic and phasic) could potentially explain this discrepancy. Objective: To investigate the potential role of phasic DA release in 50-kHz call emission. Methods: In Experiment 1, USVs were recorded in adult male rats following unexpected electrical stimulation of the medial forebrain bundle (MFB). In parallel, phasic DA release in the nucleus accumbens (NAcc) was recorded using fast-scan cyclic voltammetry. In Experiment 2, USVs were recorded following response-contingent or non-contingent optogenetic stimulation of midbrain DAergic neurons. Four 20-s schedules of optogenetic stimulation were used: fixed-interval, fixed-time, variable-interval, and variable-time. Results: Brief electrical stimulation of the MFB increased both 50-kHz call rate and phasic DA release in the NAcc. During optogenetic stimulation sessions, rats initially called at a high rate comparable to that observed following reinforcers such as psychostimulants. Although optogenetic stimulation maintained reinforced responding throughout the 2-h session, the call rate declined to near zero within the first 30 min. The trill call subtype predominated following both electrical and optical stimulation. Conclusion: The occurrence of electrically-evoked 50-kHz calls, time-locked to phasic DA (Experiment 1), provides correlational evidence supporting a role for phasic DA in USV production. However, in Experiment 2, the temporal dissociation between calling and optogenetic stimulation of midbrain DAergic neurons suggests that phasic mesolimbic DA release is not sufficient to produce 50-kHz calls. The emission of the trill subtype of 50-kHz calls

  9. Rapid regulation of depression-related behaviours by control of midbrain dopamine neurons.

    PubMed

    Chaudhury, Dipesh; Walsh, Jessica J; Friedman, Allyson K; Juarez, Barbara; Ku, Stacy M; Koo, Ja Wook; Ferguson, Deveroux; Tsai, Hsing-Chen; Pomeranz, Lisa; Christoffel, Daniel J; Nectow, Alexander R; Ekstrand, Mats; Domingos, Ana; Mazei-Robison, Michelle S; Mouzon, Ezekiell; Lobo, Mary Kay; Neve, Rachael L; Friedman, Jeffrey M; Russo, Scott J; Deisseroth, Karl; Nestler, Eric J; Han, Ming-Hu

    2013-01-24

    Ventral tegmental area (VTA) dopamine neurons in the brain's reward circuit have a crucial role in mediating stress responses, including determining susceptibility versus resilience to social-stress-induced behavioural abnormalities. VTA dopamine neurons show two in vivo patterns of firing: low frequency tonic firing and high frequency phasic firing. Phasic firing of the neurons, which is well known to encode reward signals, is upregulated by repeated social-defeat stress, a highly validated mouse model of depression. Surprisingly, this pathophysiological effect is seen in susceptible mice only, with no apparent change in firing rate in resilient individuals. However, direct evidence--in real time--linking dopamine neuron phasic firing in promoting the susceptible (depression-like) phenotype is lacking. Here we took advantage of the temporal precision and cell-type and projection-pathway specificity of optogenetics to show that enhanced phasic firing of these neurons mediates susceptibility to social-defeat stress in freely behaving mice. We show that optogenetic induction of phasic, but not tonic, firing in VTA dopamine neurons of mice undergoing a subthreshold social-defeat paradigm rapidly induced a susceptible phenotype as measured by social avoidance and decreased sucrose preference. Optogenetic phasic stimulation of these neurons also quickly induced a susceptible phenotype in previously resilient mice that had been subjected to repeated social-defeat stress. Furthermore, we show differences in projection-pathway specificity in promoting stress susceptibility: phasic activation of VTA neurons projecting to the nucleus accumbens (NAc), but not to the medial prefrontal cortex (mPFC), induced susceptibility to social-defeat stress. Conversely, optogenetic inhibition of the VTA-NAc projection induced resilience, whereas inhibition of the VTA-mPFC projection promoted susceptibility. Overall, these studies reveal novel firing-pattern- and neural

  10. Practical issues related to uterine pathology: staging, frozen section, artifacts, and Lynch syndrome.

    PubMed

    Soslow, Robert A

    2016-01-01

    This review covers three areas in endometrial tumor pathology: International Federation of Gynecology and Obstetrics (FIGO) staging, the use of frozen section, and Lynch syndrome. The section on FIGO staging will emphasize problems that practicing pathologists often confront, such as measuring the depth of myometrial invasion, assessing for the presence of cervical stromal invasion, detecting low-volume lymph node metastases, and recognizing synchronous endometrial and ovarian tumors and artifacts. The frozen section portion of this review will focus on the performance characteristics of intraoperative examination of the uterus to determine tumor grade and depth of myometrial invasion, including suggestions for alternative methods. The last portion of this review will provide an overview of Lynch syndrome and a discussion of the rationale and methods of screening for Lynch syndrome.

  11. Spontaneous endomyometrial neoplasms in aging Chinese hamsters

    SciTech Connect

    Brownstein, D.G.; Brooks, A.L.

    1980-05-01

    Twenty-one endomyometrial neoplasms among 93 nulliparous noninbred Chinese hamsters were evaluated. The median survival time of the 93 females was 1040 days. The median age of hamsters with endomyometrial neoplasms was 1200 days. Neoplasms were classified as carcinomas or malignant mixed muellerian tumors of the endometrium and benign or malignant myometrial neoplasms. There were 13 endometrial adenocarcinomas. Three tumors were mixed adenosquamous carcinomas, which occurred in significantly older Chinese hamsters than did adenocarcinomas. Three malignant mixed muellerian tumors consisted of 2 carcinosarcomas and 1 mixed mesodermal tumor. The 2 myometrial neoplasms were a lelomyoma and a lelomyosarcoma. The classification and relative frequency of these neoplasms were similar to endomyometrial neoplasms of women, which makes Chinese hamsters useful subjects for studies of spontaneous endomyometrial cancers.

  12. Determination of the functional size of oxytocin receptors in plasma membranes from mammary gland and uterine myometrium of the rat by radiation inactivation

    SciTech Connect

    Soloff, M.S.; Beauregard, G.; Potier, M.

    1988-05-01

    Gel filtration of detergent-solubilized oxytocin (OT) receptors in plasma membrane fractions from both regressed mammary gland and labor myometrium of the rat, showed that specific (/sup 3/H)OT binding was associated with a heterogeneously sized population of macromolecules. As radiation inactivation is the only method available to measure the apparent molecular weights of membrane proteins in situ, we used this approach to define the functional sizes of OT receptors. The results indicate that both mammary and myometrial receptors are uniform in size and of similar molecular mass. Mammary and myometrial receptors were estimated to be 57.5 +/- 3.8 (SD) and 58.8 +/- 1.6 kilodaltons, respectively. Knowledge of the functional size of OT receptors will be useful in studies involving the purification and characterization of the receptor and associated membrane components.

  13. The oxytocin receptor gene (OXTR) localizes to human chromosome 3p25 by fluorescence in situ hybridization and PCR analysis of somatic cell hybrids

    SciTech Connect

    Simmons, C.F. Jr.; Clancy, T.E.; Quan, R.

    1995-04-10

    The human oxytocin receptor regulates parturition and myometrial contractility, breast milk let-down, and reproductive behaviors in the mammalian central nervous system. Kimura et al. recently identified a human oxytocin receptor cDNA by means of expression cloning from a human myometrial cDNA library. To elucidate further the molecular mechanisms that regulate oxytocin receptor gene expression and to define the expected Mendelian inheritance of possible human disease states, we must determine the number of genes, their localization, and their organization and structure. We summarize below our data indicating that the human oxytocin receptor gene is localized to 3p25 and exists as a single copy in the haploid genome. 9 refs., 2 figs.

  14. Endometrial adenocarcinoma, adjuvant radiotherapy tailored to prognostic factors.

    PubMed

    Meerwaldt, J H; Hoekstra, C J; van Putten, W L; Tjokrowardojo, A J; Koper, P C

    1990-02-01

    The optimal adjuvant radiotherapy for surgically treated endometrial cancer has not yet been defined. We report on 389 patients treated between 1970 and 1985 with adjuvant radiotherapy. The treatment was tailored to the known prognostic factors: myometrial invasion and grade of differentiation of the tumor. Ten-year overall survival was 67%, 10-year relapse-free survival 77%; 23% relapse, of which 21% distant and 6% locoregional relapse. In a multivariate analysis, stage (pT), grade, and myometrial invasion were prognostic factors. The number of locoregional failures was very small (n = 23). This small number, the fact that radiation treatment was tailored to prognostic factors, and the absence of a nontreated control group precluded an analysis of the effect of the adjuvant irradiation. Large randomized studies with a control (no treatment) arm should be performed to determine the value of adjuvant radiotherapy. PMID:2303362

  15. MR imaging findings of uterine pyomyoma: radiologic-pathologic correlation.

    PubMed

    Ono, Hiromi; Kanematsu, Masayuki; Kato, Hiroki; Toyoki, Hiroshi; Hayasaki, Yoh; Furui, Tatsuro; Morishige, Ken-ichirou; Hatano, Yuichiro

    2014-08-01

    A 69-year-old postmenopausal female with a spontaneously occurring uterine pyomyoma was described with emphasis on the MR imaging findings. On unenhanced T1- and T2-weighted MR images, a huge mottled mass suspected to contain blood products, necrotic tissue, or purulent or viscous fluid was demonstrated within anterior myometrial wall of uterine body. The mass was surrounded by a peripheral rim that was hyperintense on T1-weighted images and hypointense on T2-weighted images. On gadolinium-enhanced MR images, most of the mass was unenhanced, but the peripheral rim was equally enhanced with the surrounding myometrium. Pathological examination revealed an intramural uterine pyomyoma surrounded by fibrous capsules with abundant lymphocytes and neutrophils. Our findings indicate that pyomyoma should be considered when MR images demonstrate a myometrial cystic lesion accompanied by a peripheral rim. PMID:24615512

  16. Hydropic leiomyoma of the uterus presenting as a giant abdominal mass.

    PubMed

    Horta, Mariana; Cunha, Teresa Margarida; Oliveira, Rita; Magro, Paula

    2015-01-01

    We describe a case of a 35-year-old woman with a pedunculated uterine leiomyoma with diffuse hydropic degeneration presenting as a giant abdominal mass. The patient was admitted in the emergency department because of diffuse abdominal bloating and discomfort. Ultrasonography (US) showed a heterogeneous abdominopelvic mass. Magnetic resonance imaging (MRI) was performed to further characterise and revealed a myometrial pedunculated tumour. Despite its marked T2-signal heterogeneity and volume, there were no other suspicious findings to suggest a malignant nature; therefore, fertility-sparing myomectomy was performed. Leiomyomas frequently undergo degenerative changes altering their imaging appearances. Leiomyomas with uncommon degenerative changes may be difficult to differentiate from malignant myometrial tumours, based solely on imaging. To the best of our knowledge, a diffuse hydropic degeneration imaging appearance has only been described twice in the literature. We describe the imaging appearance of this rare form of leiomyoma drawing attention to its differential diagnosis.

  17. Practical issues related to uterine pathology: staging, frozen section, artifacts, and Lynch syndrome.

    PubMed

    Soslow, Robert A

    2016-01-01

    This review covers three areas in endometrial tumor pathology: International Federation of Gynecology and Obstetrics (FIGO) staging, the use of frozen section, and Lynch syndrome. The section on FIGO staging will emphasize problems that practicing pathologists often confront, such as measuring the depth of myometrial invasion, assessing for the presence of cervical stromal invasion, detecting low-volume lymph node metastases, and recognizing synchronous endometrial and ovarian tumors and artifacts. The frozen section portion of this review will focus on the performance characteristics of intraoperative examination of the uterus to determine tumor grade and depth of myometrial invasion, including suggestions for alternative methods. The last portion of this review will provide an overview of Lynch syndrome and a discussion of the rationale and methods of screening for Lynch syndrome. PMID:26715174

  18. PI(3,4,5)P3 Potentiates Phospholipase C-β Activity

    PubMed Central

    Zhang, Yong; Kwon, Sun Hyung; Vogel, Walter K.; Filtz, Theresa M.

    2010-01-01

    Phospholipase C-β (PLC-β) isozymes are key effectors in G protein-coupled signaling pathways. Previously, we had shown that PLC-β1 and PLC-β3 bound immobilized PIP3. In this study, PIP3 was found to potentiate Ca2+-stimulated PLC-β activities using an in vitro reconstitution assay. LY294002, a specific PI 3-kinase inhibitor, significantly inhibited 10 minutes agonist-stimulated total IP accumulation. Both LY294002 and wortmannin inhibited 90 seconds agonist-stimulated IP3 accumulation in intact cells. Moreover, transfected p110CAAX, a constitutively activated PI 3-kinase catalytic subunit, increased 90 seconds oxytocin-stimulated IP3 accumulation. Receptor-ligand binding assays indicated that LY294002 did not affect G protein-coupled receptors directly, suggesting a physiological role for PIP3 in directly potentiating PLC-β activity. When co-expressed with p110CAAX, fluorescence-tagged PLC-β3 was increasingly localized to the plasma membrane. Additional observations suggest that the PH domain of PLC-β is not important for p110CAAX-induced membrane association. PMID:19519170

  19. Fluorescence measurements of anion transport by the GABA receptor in reconstituted membrane preparations

    SciTech Connect

    Dunn, S.M.J.; Shelman, R.A.; Agey, M.W. )

    1989-03-21

    A fluorescence assay for measuring the functional properties of the GABA{sub A} receptor in reconstituted membrane vesicles is described. This assay is based on a method previously described to measure monovalent cation transport mediated by the nicotinic acetylcholine receptor in membranes from Torpedo electric organ. The GABA{sub A} receptor has been solubilized from bovine brain membranes and reconstituted into phospholipid vesicles. Influx of chloride or iodide into the vesicles has been measured in stopped-flow experiments by monitoring the fluorescence quench of an anion-sensitive fluorophore trapped within the vesicles. Muscimol, a GABA{sub A} receptor agonist, stimulated a rapid uptake of either chloride or iodide. Stimulation of chloride influx was dependent on the concentration of muscimol, and the midpoint of the dose-response curve occurred at approximately 0.3 {mu}M. Agonist-stimulated uptake was enhanced by diazepam and blocked by desensitization and by the antagonists bicuculline and picrotoxin. These receptor-mediated effects are shown to be qualitatively similar to measurements of {sup 36}Cl{sup {minus}} and {sup 125}I{sup {minus}} efflux using synaptoneurosomes prepared from rat cerebral cortex. The advantages of the fluorescence method in terms of its improved time resolution, sensitivity, and suitability for quantitating GABA{sub A} receptor function are discussed.

  20. Catecholamine differential modulation of PMA and superantigen stimulated lymphocytes

    SciTech Connect

    Downs, M.O.; Johnson, H.M. )

    1991-03-15

    Neurotransmitters have been demonstrated to be important modulators of immune regulation. The authors have previously demonstrated that the catecholamine agonists isoproterenol (Iso), epinephrine (Epi), and norepinephrine (Nor) are potent inhibitors of IFN{gamma} production by phorbol myristate acetate (PMA) stimulated T-cell lymphoma cell line (L12-R4) with the order of potency being Iso > Epi > Nor. Herein, they describe a differential effect of catecholamine influence on staphylococcal enterotoxin A (SEA) stimulated murine splenic cell cultures. Norepinephrine and to a lesser extent Epi can cause a biphasic modulation of IFN{gamma} production. Inhibition of INF{gamma}was seen in the micromolar range while augmentation occurred at the nanomolar range. In light of previous work, these data suggest that {beta}-adrenergic agonist stimulation of antigen presenting cells (APC) may be immunosuppressive while {alpha}-agonist stimulation immunopotentiating. Further, APC may play a central role in determining the net outcome of catecholamine stimulation by being able to mediate signals from both pathways. This response may represent a peripheral neurotransmitter mediated mechanism for fine tuning' immunoreactivity.

  1. Effect of ticlopidine ex vivo on platelet intracellular calcium mobilization

    SciTech Connect

    Derian, C.K.; Friedman, P.A.

    1988-04-01

    The antiplatelet compound ticlopidine exerts its potent inhibitory activity through an as yet undetermined mechanism(s). The goal of this study was to determine the effect, if any, of ticlopidine ex vivo on platelet calcium mobilization. Ticlopidine inhibited ADP-induced platelet aggregation by 50-80%. In the presence of 1 mM EGTA, ticlopidine inhibited ADP- and thrombin-stimulated increases in (Ca2+)i in fura-2 loaded platelets. We evaluated further the effect of ticlopidine on calcium mobilization by examining both agonist-stimulated formation of inositol trisphosphate in intact platelets and the ability of inositol trisphosphate to release /sup 45/Ca from intracellular sites in permeabilized cells. We show here that while ticlopidine significantly affected agonist-induced intracellular calcium mobilization in intact platelets, the drug was without effect on agonist-stimulated formation of inositol trisphosphate in intact platelets and on inositol trisphosphate-induced /sup 45/Ca release in saponin-permeabilized platelets. Our study demonstrates that ticlopidine exerts at least part of its effect via inhibition of intracellular calcium mobilization but that its site of action remains to be determined.

  2. Single-cell mechanics and calcium signalling in organotypic slices of human myometrium☆

    PubMed Central

    Loftus, Fiona C.; Richardson, Magnus J.E.; Shmygol, Anatoly

    2015-01-01

    Elucidation of cellular mechanisms regulating myometrial contractility is crucial for improvement in management of many obstetric abnormalities, such as premature delivery, uterine dystocia and post-partum haemorrhage. Myometrial contractions are triggered by periodic synchronous rises in intracellular calcium concentration ([Ca2+]i) elicited by spontaneously generated action potentials propagating throughout the entire myometrium. During labour, hormones like oxytocin and prostaglandins potentiate uterine contractions by increasing their duration, strength and frequency. The most informative approach to studying the mechanisms underlying hormonal modulation of uterine contractility is to record [Ca2+]i responses to hormones in intact myometrial samples that have not been subjected to enzymatic treatment for cell isolation or cell culture conditions. However, the spatio-temporal resolution of such recording is limited due to the motion artifacts occurring in contracting tissue. Here we describe the application of our newly developed motion correction algorithm to investigate the [Ca2+]i dynamics in control and oxytocin stimulated slices of human myometrium on a cellular level. We present evidence that oxytocin induces asynchronous [Ca2+]i oscillations in individual myocytes within intact myometrium which are similar to those observed in cultured cells. The oscillations occur between synchronous action potential-driven [Ca2+]i transients but appear to be unrelated to contractions. Furthermore, the oxytocin-triggered [Ca2+]i oscillations wane within 30–50 min of hormone application, while the action potential induced [Ca2+]i transients remain augmented. We conclude that oxytocin-induced [Ca2+]i oscillations are not relevant to the acute regulation of myometrial contractility but may play a role in longer-term regulatory processes, for example, by triggering gene expression. PMID:25702249

  3. G protein-coupled estrogen receptor 1-mediated effects in the rat myometrium.

    PubMed

    Tica, Andrei A; Dun, Erica C; Tica, Oana S; Gao, Xin; Arterburn, Jeffrey B; Brailoiu, G Cristina; Oprea, Tudor I; Brailoiu, Eugen

    2011-11-01

    G protein-coupled estrogen receptor 1 (GPER), also named GPR30, has been previously identified in the female reproductive system. In this study, GPER expression was found in the female rat myometrium by reverse transcriptase-polymerase chain reaction and immunocytochemistry. Using GPER-selective ligands, we assessed the effects of the GPER activation on resting membrane potential and cytosolic Ca(2+) concentration ([Ca(2+)](i)) in rat myometrial cells, as well as on contractility of rat uterine strips. G-1, a specific GPER agonist, induced a concentration-dependent depolarization and increase in [Ca(2+)](i) in myometrial cells. The depolarization was abolished in Na(+)-free saline. G-1-induced [Ca(2+)](i) increase was markedly decreased by nifedipine, a L-type Ca(2+) channel blocker, by Ca(2+)-free or Na(+)-free saline. Intracellular administration of G-1 produced a faster and transitory increase in [Ca(2+)](i), with a higher amplitude than that induced by extracellular application, supporting an intracellular localization of the functional GPER in myometrial cells. Depletion of internal Ca(2+) stores with thapsigargin produced a robust store-activated Ca(2+) entry; the Ca(2+) response to G-1 was similar to the constitutive Ca(2+) entry and did not seem to involve store-operated Ca(2+) entry. In rat uterine strips, administration of G-1 increased the frequency and amplitude of contractions and the area under the contractility curve. The effects of G-1 on membrane potential, [Ca(2+)](i), and uterine contractility were prevented by pretreatment with G-15, a GPER antagonist, further supporting the involvement of GPER in these responses. Taken together, our results indicate that GPER is expressed and functional in rat myometrium. GPER activation produces depolarization, elevates [Ca(2+)](i) and increases contractility in myometrial cells.

  4. Expression of freezing and fear-potentiated startle during sustained fear in mice.

    PubMed

    Daldrup, T; Remmes, J; Lesting, J; Gaburro, S; Fendt, M; Meuth, P; Kloke, V; Pape, H-C; Seidenbecher, T

    2015-03-01

    Fear-potentiated acoustic startle paradigms have been used to investigate phasic and sustained components of conditioned fear in rats and humans. This study describes a novel training protocol to assess phasic and sustained fear in freely behaving C57BL/6J mice, using freezing and/or fear-potentiated startle as measures of fear, thereby, if needed, allowing in vivo application of various techniques, such as optogenetics, electrophysiology and pharmacological intervention, in freely behaving animals. An auditory Pavlovian fear conditioning paradigm, with pseudo-randomized conditioned-unconditioned stimulus presentations at various durations, is combined with repetitive brief auditory white noise burst presentations during fear memory retrieval 24 h after fear conditioning. Major findings are that (1) a motion sensitive platform built on mechano-electrical transducers enables measurement of startle responses in freely behaving mice, (2) absence or presence of startle stimuli during retrieval as well as unpredictability of a given threat determine phasic and sustained fear response profiles and (3) both freezing and startle responses indicate phasic and sustained components of behavioral fear, with sustained freezing reflecting unpredictability of conditioned stimulus (CS)/unconditioned stimulus (US) pairings. This paradigm and available genetically modified mouse lines will pave the way for investigation of the molecular and neural mechanisms relating to the transition from phasic to sustained fear.

  5. Extending the Rescorla-Wagner theory to account for transswitching.

    PubMed

    Lachnit, H; Kimmel, H D

    1991-01-01

    This article is a brief response to commentaries made by Bond and Siddle (1988) and Lovibond (1988) to our article (Kimmel & Lachnit, 1988) outlining some of the difficulties encountered by the Rescorla-Wagner theory in predicting the outcome of transswitching experiments. We show that Bond and Siddle's assertion that increasing the value of beta would "bring the model into line with the empirical data" (p. 186) is incorrect. Increasing beta in simulated transswitching experiments causes the theory to predict a more rapid increase in associative values, to higher levels, but does not change the degree of predicted phasic switching. We agree with Lovibond's observation that the Rescorla-Wagner theory can predict phasic switching more effectively if it is assumed that an unobserved additional stimulus is present whenever the phasic stimulus occurs in positive tonic segments and a different unobserved additional stimulus is present whenever the phasic stimulus occurs in negative tonic segments. But this kind of usage of the "unique cue hypothesis" does little more then immunize a theory against problematic empirical findings. When the salience of the unique cue is increased relative to that of the stimuli that are actually physically present, simulated transswitching experiments show greater and greater phasic switching. But, unless there is a good a priori reason to postulate such unique cues, or unless the unique cue hypothesis leads to empirically testable new hypotheses, it does not provide a scientifically useful solution to the theory's problem with transswitching.

  6. Scallops show that muscle metabolic capacities reflect locomotor style and morphology.

    PubMed

    Tremblay, Isabelle; Guderley, Helga E

    2014-01-01

    Although all scallops swim using their adductor muscle to close their valves, scallop species differ considerably in how they use their muscle during escape responses, in parallel with the striking interspecific differences in shell morphology. This provides an excellent opportunity to study links between muscle metabolic capacities and animal performance. We found that the capacity for anaerobic glycolysis and aerobic metabolism, as well as phosphoarginine levels in the phasic adductor muscle, differ with escape response strategy. Phosphoarginine contents were high in species that rely on phasic contractions (Amusium balloti, Placopecten magellanicus, and Pecten fumatus). Arginine kinase activities reflect reliance on rapid initial bursts of phasic contractions. Scallops that maintain their valves in a closed position for prolonged periods (P. fumatus, Mimachlamys asperrima, and Crassadoma gigantea) have high activities of enzymes of anaerobic glycolysis in their phasic adductor muscle. Myosin ATPase activity was lower in the nonswimming scallop, C. gigantea, than in swimming scallops. The different patterns and roles of swimming are reflected in interspecific differences in the biochemical attributes of the phasic adductor muscle. These patterns suggest coevolution of muscle metabolic capacities, patterns of adductor muscle use, and shell morphology in scallops. PMID:24642541

  7. Patterns of Phrenic Nerve Discharge after Complete High Cervical Spinal Cord Injury in the Decerebrate Rat.

    PubMed

    Ghali, Michael George Zaki; Marchenko, Vitaliy

    2016-06-15

    Studies conducted since the second half of the 19th century have revealed spontaneous as well as pharmacologically induced phasic/rhythmic discharge in spinal respiratory motor outputs of cats, dogs, rabbits, and neonatal rats following high cervical transection (Tx). The extent to which these various studies validate the existence of a true spinal respiratory rhythm generator remains debated. In this set of studies, we seek to characterize patterns of spontaneous phasic/rhythmic, asphyxia-induced, and pharmacologically induced activity occurring in phrenic nerve (PhN) discharge after complete high cervical (C1-C2) spinal cord transection. Experiments were performed on 20 unanesthetized decerebrate Sprague-Dawley adult male rats. Patterns of spontaneous activity after spinalization included tonic, phasic, slow oscillatory, and long-lasting tonic discharges. Topical application of antagonists of GABAA and glycine receptors to C1- and C2- spinal segments induced left-right synchronized phasic decrementing activity in PhN discharge that was abolished by an additional C2Tx. Asphyxia elicited increases in tonic activity and left-right synchronized gasp-like bursts in PhN discharge, demonstrating the presence of spinal circuits that may underlie a spinal gasping-like mechanism. We conclude that intrinsic slow oscillators and a phasic burst/rhythm generator exist in the spinal cord of the adult rat. If present in humans, this mechanism may be exploited to recover respiratory function in patients sustaining severe spinal cord injury. PMID:26239508

  8. Multifocal uterine myxoid change: a newly recognized association with neurofibromatosis type 1.

    PubMed

    Pugh, Abigail; McCluggage, W Glenn; Hirschowitz, Lynn

    2012-11-01

    Stromal myxoid change is a rare feature of non-neoplastic disease of the uterus. "Myometrial myxoidosis" with secondary myometrial hypertrophy was reported in 2 patients with systemic lupus erythematosus. Uterine myxoid stromal change was also described as an unusual pseudoneoplastic condition of uncertain etiology in 3 patients, one of whom had neurofibromatosis type 1 (NF1; von Recklinghausen disease). We have now identified multifocal uterine myxoid change in the hysterectomy specimen of another patient with NF1; we describe the findings in both patients and review the relevant literature. The myometrium and cervical stroma in both NF1 patients contained tracts and nodules of hypocellular myxoid stromal material composed of bland spindle-shaped cells and interspersed small blood vessels. The myxoid stromal material was strongly and diffusely immunopositive for CD34 and CD10 but did not label for desmin, smooth muscle actin, h-caldesmon, neurofilament protein, S100, or epithelial membrane antigen. The myxoid material in the NF1 patients was better demarcated than in the 2 reported cases of myometrial myxoidosis in systemic lupus erythematosus, and more widely distributed, extensively involving the cervix and the myometrium. The occurrence of this rare, distinctive pattern of multifocal uterine myxoid change in 2 patients with NF1 seems unlikely to represent simply a chance association. The identification of multifocal uterine myxoid change in non-neoplastic myometrium or cervical stroma should raise the possibility of underlying NF1.

  9. Calcium-activated chloride channels anoctamin 1 and 2 promote murine uterine smooth muscle contractility

    PubMed Central

    Bernstein, Kyra; Vink, Joy Y; Fu, Xiao Wen; Wakita, Hiromi; Danielsson, Jennifer; Wapner, Ronald; Gallos, George

    2014-01-01

    Objective To determine the presence of calcium activated chloride channels anoctamin 1 and 2 in human and murine uterine smooth muscle and evaluate the physiologic role for these ion channels in murine myometrial contractility. Study Design We performed reverse transcription polymerase chain reaction to determine if anoctamin 1 and 2 are expressed in human and murine uterine tissue to validate the study of this protein in mouse models. Immunohistochemical staining of anoctamin 1 and 2 was then performed to determine protein expression in murine myometrial tissue. The function of anoctamin 1 and 2 in murine uterine tissue was evaluated using electrophysiological studies, organ bath, and calcium flux experiments. Results Anoctamin 1 and 2 are expressed in human and murine USM cells. Functional studies show that selective antagonism of these channels promotes relaxation of spontaneous murine uterine smooth muscle contractions. Blockade of anoctamin 1 and 2 inhibits both agonist-induced and spontaneous transient inward currents and abolishes G-protein coupled receptor (oxytocin) mediated elevations in intracellular calcium. Conclusion The calcium activated chloride channels ANO 1 and 2 are present in human and murine myometrial tissue and may provide novel potential therapeutic targets to achieve effective tocolysis. PMID:24928056

  10. Slit2 is decreased after spontaneous labour in myometrium and regulates pro-labour mediators.

    PubMed

    Lim, Ratana; Liong, Stella; Barker, Gillian; Lappas, Martha

    2014-12-01

    Preterm birth, a global healthcare problem, is commonly associated with inflammation. As Slit2 plays an emerging role in inflammation, the purpose of this study was to determine the effect of Slit2 on labour mediators in human gestational tissues. Slit2 mRNA and protein expression were assessed using qRT-PCR and immunohistochemistry in foetal membranes and myometrium obtained before and after labour. Slit2 silencing was achieved using siRNA in primary myometrial cells. Pro-inflammatory and pro-labour mediators were evaluated by qRT-PCR, ELISA and gelatin zymography. Slit2 mRNA and protein expression were found to be significantly lower in myometrium after labour onset. There was no effect of term or preterm labour on Slit2 expression in foetal membranes. Slit2 mRNA expression was decreased in myometrium treated with LPS and IL-1β. Slit2 siRNA in myometrial cells increased IL-1β-induced pro-inflammatory cytokine gene expression and release (IL-6 and IL-8), COX-2 expression and prostaglandin PGE2 and PGF2α release, and MMP-9 gene expression and pro MMP-9 release. There was no effect of Slit2 siRNA on IL-1β-induced NF-κB transcriptional activity. Our results demonstrate that Slit2 is decreased in human myometrium after labour and our knock-down studies describe an anti-inflammatory effect of Slit2 in myometrial cells.

  11. Subcellular localization and regulation of type-1C and type-5 phosphodiesterases

    SciTech Connect

    Dolci, Susanna; Belmonte, Alessia; Santone, Rocco; Giorgi, Mauro; Pellegrini, Manuela; Carosa, Eleonora; Piccione, Emilio; Lenzi, Andrea; Jannini, Emmanuele A. . E-mail: jannini@univaq.it

    2006-03-17

    We investigated the subcellular localization of PDE5 in in vitro human myometrial cells. We demonstrated for First time that PDE5 is localized in discrete cytoplasmic foci and vesicular compartments corresponding to centrosomes. We also found that PDE5 intracellular localization is not cell- or species-specific, as it is conserved in different animal and human cells. PDE5 protein levels are strongly regulated by the mitotic activity of the smooth muscle cells (SMCs), as they were increased in quiescent, contractile myometrial cultures, and conditions in which proliferation was inhibited. In contrast, PDE1C levels decreased in all conditions that inhibited proliferation. This mirrored the enzymatic activity of both PDE5 and PDE1C. Increasing cGMP intracellular levels by dbcGMP or sildenafil treatments did not block proliferation, while dbcAMP inhibited myometrial cell proliferation. Together, these results suggest that PDE5 regulation of cGMP intracellular levels is not involved in the control of SMC cycle progression, but may represent one of the markers of the contractile phenotype.

  12. Effects of Hormonally Active Agents on Steroid Hormone Receptor Expression and Cell Proliferation in the Myometrium of Ovariectomized Macaques

    PubMed Central

    Hill, Georgette D.; Moore, Alicia B.; Kissling, Grace E.; Flagler, Norris D.; Ney, Elizabeth; Cline, J. Mark; Dixon, Darlene

    2011-01-01

    Hormone replacement therapy and selective estrogen receptor modulators have been controversial treatment options for postmenopausal women because of their potential health benefits and/or risks. In this study, we determine the effects of the hormonally active compounds, conjugated equine estrogens (CEE), medroxyprogesterone acetate (MPA), CEE + MPA, and tamoxifen (TAM) on the myometrium of ovariectomized macaques. Immunoexpression of estrogen receptor-α (ERα), progesterone receptor (PR), and Ki-67 in the myometrium is assessed. We found no significant difference in ERα myometrial expression in the CEE, MPA, and CEE + MPA treatment groups, but there was a significant decrease in expression in animals administered TAM versus controls. Conjugated equine estrogen−, TAM−, and CEE + MPA-treated animals had significantly increased expression of PR in myometrial cells and there was no difference in PR expression in cells from MPA-treated animals versus control animals. Myometrial cell proliferation did not significantly differ between the controls and any of the treatment groups, although normalized Ki-67 values were somewhat higher in the CEE and TAM groups. These data suggest that ERα and PR expression in the myometrium is influenced by treatment with hormonally active agents. PMID:21411722

  13. G-1-activated membrane estrogen receptors mediate increased contractility of the human myometrium.

    PubMed

    Maiti, K; Paul, J W; Read, M; Chan, E C; Riley, S C; Nahar, P; Smith, R

    2011-06-01

    Estrogens are key mediators of increased uterine contractility at labor. We sought to determine whether membrane-associated estrogen receptors, such as the recently described seven-transmembrane receptor G protein-coupled receptor 30 (GPR30), mediated some of this effect. Using human myometrium obtained at term cesarean section before or after the onset of labor, we demonstrated the presence of GPR30 mRNA and protein using quantitative RT-PCR and Western blotting. GPR30 receptor was localized to the cell membrane and often colocalized with calveolin-1. Using the specific estrogen membrane receptor agonist G-1 and myometrial explants, we showed that membrane receptor activation led to phosphorylation of MAPK and the actin-modifying small heat shock protein 27. Using myometrial strips incubated with G-1 or vehicle we demonstrated that estrogen membrane receptor activation increased the myometrial contractile response to oxytocin. These data suggest that activation of the plasma membrane estrogen receptor GPR30 likely participates in the physiology of the human myometrium during pregnancy and identifies it as a potential target to modify uterine activity. PMID:21427217

  14. Reduced expression of immunoreactive beta2-adrenergic receptor protein in human myometrium with labor.

    PubMed

    Chanrachakul, Boonsri; Matharoo-Ball, Balwir; Turner, Anita; Robinson, Graham; Broughton-Pipkin, Fiona; Arulkumaran, Sabaratnam; Khan, Raheela N

    2003-10-01

    A considerable body of evidence exists suggesting that the beta(2)-adrenergic receptor (beta(2)-AR) mediates uterine relaxation. However, little information exists on the localization, distribution, or expression of beta(2)-ARs in the human myometrium during the nonpregnant to labor transition. We have used immunochemical methods to investigate beta(2)-AR localization and expression in the nonpregnant, term pregnant, and term parturient uterus. Myometrial biopsies were obtained from 1) nonpregnant, menstruating women undergoing hysterectomy; 2) singleton term pregnant women undergoing elective cesarean section before the onset of labor; or 3) singleton term pregnant women undergoing emergency cesarean section after spontaneous labor. Tissues were processed for immunohistochemistry, immunofluorescence, and Western blotting and a primary polyclonal antibody specific to the human beta(2)-AR to identify immunoreactive myometrial beta(2)-AR. Protein levels were subsequently quantified by densitometry relative to rat brain protein. Immunohistochemistry and immunofluorescence demonstrated the presence of beta(2)-AR predominantly at the plasma membrane and also in the cytosol of myometrial cells. A 2-fold decrease in protein levels of the beta(2)-AR was apparent in the myometrium of labor compared with that of nonpregnant and pregnant nonlaboring women (P < 0.05). These results demonstrate that down-regulation of beta(2)-AR protein with labor may constitute a contributory mechanism by which uterine quiescence is removed at term.

  15. [Myocardial contractility and hemodynamics in hypothyroidism].

    PubMed

    Selivonenko, V G

    1977-01-01

    The author determined the phasic structure of the systole of the left ventricle by the method of polycardiography and hemodynamics in 20 patients suffering from hypothyrodism. Blood plasma and erythrocyte electrolytes were examined at the same time. Patients with hypothyroidism displayed a phasic syndrome of hypodynamia and a marked correlation between the phase of the synchronous contraction, the period of ejection, the strength of contraction of the left ventricle and the electrolyte content. Sodium and magnesium produced the greatest influence on the phasic structure of the systole; potassium and calcium had a lesser effect. The heart stroke volume diminished; as to the cardiac index, expenditure of the energy of cardiac contractions directed to the maintenance of movement of 1 litre of the minute blood volume; the external work, and the peripheral vascular resistance displayed no significant change.

  16. Identification of cone mechanisms in monkey ganglion cells

    PubMed Central

    Gouras, Peter

    1968-01-01

    1. Blue, green, and red sensitive cone mechanisms have been studied in two types of on-centre ganglion cells in the Rhesus monkey's retina. 2. One type of cell receives signals from both green and red sensitive cone mechanisms, both of which excite in the centre and inhibit in the periphery of the cell's receptive field. These cells discharge transiently to maintained stimuli of any wave-length and are called phasic. 3. The second type of cell receives excitatory signals from only one cone mechanism, either blue, green or red sensitive, in the centre, and inhibition from another cone mechanism in the periphery of its receptive field. These cells discharge continuously to maintained stimuli of appropriate wave-length and are called tonic. 4. Tonic cells outnumber phasic cells although both are found adjacent to one another throughout the retina. Phasic cells are relatively more common toward the periphery and tonic cells relatively more common toward the fovea. PMID:4974745

  17. A model for multiphase flows through poroelastic media

    SciTech Connect

    Ahmadi, Goodarz; Mazaheri, Ali Reza; Smith, D.H

    2003-01-01

    A continuum model for multiphase fluid mixture flows through poroelastic media is presented. The basic conservation laws developed via a volume averaging technique are considered. Effects of phasic equilibrated forces are included in the model. Based on the thermodynamics of the multiphase mixture flows, appropriate constitutive equations are formulated. The entropy inequality is exploited, and the method of Lagrangian multiplier is used along with the phasic conservation laws to derive the constitutive equations for the phasic stress tensors, equilibrated stress vectors, and the interactions terms. The special cases of wave propagation in poroelastic media saturated with multiphase fluids, and multiphase flows through porous media, are studied. It is shown that the present theory leads to the extended Darcy’s law and contains, as a special case, Biot’s theory of saturated poroelastic media.

  18. Differential inhibitory control of semicircular canal nerve afferent-evoked inputs in second-order vestibular neurons by glycinergic and GABAergic circuits.

    PubMed

    Biesdorf, Stefan; Malinvaud, David; Reichenberger, Ingrid; Pfanzelt, Sandra; Straka, Hans

    2008-04-01

    Labyrinthine nerve-evoked monosynaptic excitatory postsynaptic potentials (EPSPs) in second-order vestibular neurons (2 degrees VN) sum with disynaptic inhibitory postsynaptic potentials (IPSPs) that originate from the thickest afferent fibers of the same nerve branch and are mediated by neurons in the ipsilateral vestibular nucleus. Pharmacological properties of the inhibition and the interaction with the afferent excitation were studied by recording monosynaptic responses of phasic and tonic 2 degrees VN in an isolated frog brain after electrical stimulation of individual semicircular canal nerves. Specific transmitter antagonists revealed glycine and GABA(A) receptor-mediated IPSPs with a disynaptic onset only in phasic but not in tonic 2 degrees VN. Compared with GABAergic IPSPs, glycinergic responses in phasic 2 degrees VN have larger amplitudes and a longer duration and reduce early and late components of the afferent nerve-evoked subthreshold activation and spike discharge. The difference in profile of the disynaptic glycinergic and GABAergic inhibition is compatible with the larger number of glycinergic as opposed to GABAergic terminal-like structures on 2 degrees VN. The increase in monosynaptic excitation after a block of the disynaptic inhibition in phasic 2 degrees VN is in part mediated by a N-methyl-d-aspartate receptor-activated component. Although inhibitory inputs were superimposed on monosynaptic EPSPs in tonic 2 degrees VN as well, the much longer latency of these IPSPs excludes a control by short-latency inhibitory feed-forward side-loops as observed in phasic 2 degrees VN. The differential synaptic organization of the inhibitory control of labyrinthine afferent signals in phasic and tonic 2 degrees VN is consistent with the different intrinsic signal processing modes of the two neuronal types and suggests a co-adaptation of intrinsic membrane properties and emerging network properties. PMID:18256163

  19. Effect of histamine on contractile activity of smooth muscles in bovine mesenteric lymph nodes.

    PubMed

    Lobov, G I; Pan'kova, M N

    2012-02-01

    The effects of histamine and mechanisms of its action on the capsular smooth muscle cells of mesenteric lymph nodes were examined on isolated capsular strips under isometric conditions. Histamine (1×10(-8)-5×10(-7) M) decreased the tone of capsular smooth muscle cells and the frequency of phasic contractions. At high concentrations (more than 5×10(-6) M), histamine increased the amplitude and frequency of phasic contractions against the background of increased tonic stress. The effects of histamine were dose-dependent and were realized via direct stimulation of H(1)- and H(2)-receptors on the membrane of smooth muscle cells.

  20. Forebrain substrates of reward and motivation.

    PubMed

    Wise, Roy A

    2005-12-01

    Electrical stimulation of the medial forebrain bundle can reward arbitrary acts or motivate biologically primitive, species-typical behaviors like feeding or copulation. The subsystems involved in these behaviors are only partially characterized, but they appear to transsynaptically activate the mesocorticolimbic dopamine system. Basal function of the dopamine system is essential for arousal and motor function; phasic activation of this system is rewarding and can potentiate the effectiveness of reward-predictors that guide learned behaviors. This system is phasically activated by most drugs of abuse and such activation contributes to the habit-forming actions of these drugs.

  1. Forebrain substrates of reward and motivation

    PubMed Central

    Wise, Roy A.

    2008-01-01

    Electrical stimulation of the medial forebrain bundle can reward arbitrary acts or motivate biologically primitive, species-typical behaviors like feeding or copulation. The sub-systems involved in these behaviors are only partially characterized, but they appear to trans-synaptically activate the mesocorticolimbic dopamine system. Basal function of the dopamine system is essential for arousal and motor function; phasic activation of this system is rewarding and can potentiate the effectiveness of reward-predictors that guide learned behaviors. This system is phasically activated by most drugs of abuse and such activation contributes to the habit-forming actions of these drugs. PMID:16254990

  2. Dopaminergic circuitry and risk/reward decision making: implications for schizophrenia.

    PubMed

    Stopper, Colin M; Floresco, Stan B

    2015-01-01

    Abnormal reinforcement learning and representations of reward value are present in schizophrenia, and these impairments can manifest as deficits in risk/reward decision making. These abnormalities may be due in part to dopaminergic dysfunction within cortico-limbic-striatal circuitry. Evidence from studies with laboratory animal have revealed that normal DA activity within different nodes of these circuits is critical for mediating dissociable processes that can refine decision biases. Moreover, both phasic and tonic dopamine transmission appear to play separate yet complementary roles in these processes. Tonic dopamine release within the prefrontal cortex and nucleus accumbens, serves as a "running rate-meter" of reward and reflects contextual information such as reward uncertainty and overt choice behavior. On the other hand, manipulations of outcome-related phasic dopamine bursts and dips suggest these signals provide rapid feedback to allow for quick adjustments in choice as reward contingencies change. The lateral habenula is a key input to the DA system that phasic signals is necessary for expressing subjective decision biases; as suppression of activity within this nucleus leads to catastrophic impairments in decision making and random patterns of choice behavior. As schizophrenia is characterized by impairments in using positive and negative feedback to appropriately guide decision making, these findings suggest that these deficits in these processes may be mediated, at least in part, by abnormalities in both tonic and phasic dopamine transmission.

  3. Tactile reception in the outer head cover of goldfish (Carassius auratus gibelio).

    PubMed

    Devitsina, G V; Lapshin, D N

    2016-01-01

    The first data on the responses of tactile receptors of the tonic, phasic, and mixed types to mechanic stimulation of the surface of head skin of fish obtained by means of noninvasive recording of potentials are presented. The sensitivity of skin tactile receptors is the highest in the circumoral and gular zones, which reflects their functional role in foraging behavior. PMID:27021364

  4. NRMRL EVALUATES ACTIVE AND SEMI-PASSIVE TECHNOLOGIES FOR TREATING ACID MINE DRAINAGE

    EPA Science Inventory

    Two-page article describing three SITE demonstration projects underway on the Leviathan mine site in California. BiPhasic lime treatment, lime treatment lagoons and compost free BioReactors are being evaluated as innovative technologies for treating acid mine drainage.

  5. Medication Impairs Probabilistic Classification Learning in Parkinson's Disease

    ERIC Educational Resources Information Center

    Jahanshahi, Marjan; Wilkinson, Leonora; Gahir, Harpreet; Dharminda, Angeline; Lagnado, David A.

    2010-01-01

    In Parkinson's disease (PD), it is possible that tonic increase of dopamine associated with levodopa medication overshadows phasic release of dopamine, which is essential for learning. Thus while the motor symptoms of PD are improved with levodopa medication, learning would be disrupted. To test this hypothesis, we investigated the effect of…

  6. New experimental techniques for studying root herbivores

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Relatively less is known about belowground ground herbivores than their aboveground counterparts . This is largely because root-feeding herbivores live in the soil, an opaque, tri-phasic medium, which makes them harder to study and perhaps less perceptible as key components of many terrestrial ecosy...

  7. "Interpersonal" Clients, Students, and Supervisees: Translating Robert Kegan

    ERIC Educational Resources Information Center

    Eriksen, Karen

    2008-01-01

    The counseling profession prides itself on its developmental focus. However, counselors, counselor educators, and supervisors have generally applied only "phasic," and not "stage," theories to counseling and supervision practice and have not incorporated developmental concepts into their teaching. This article continues the effort of rectifying…

  8. SNARE Zippering and Synaptic Strength

    PubMed Central

    Prashad, Rene C.; Charlton, Milton P.

    2014-01-01

    Synapses vary widely in the probability of neurotransmitter release. We tested the hypothesis that the zippered state of the trans-SNARE (Soluble N-ethylmaleimide-sensitive factor Attachment protein REceptor) complex determines initial release probability. We tested this hypothesis at phasic and tonic synapses which differ by 100-1000-fold in neurotransmitter release probability. We injected, presynaptically, three Clostridial neurotoxins which bind and cleave at different sites on VAMP to determine whether these sites were occluded by the zippering of the SNARE complex or open to proteolytic attack. Under low stimulation conditions, the catalytic light-chain fragment of botulinum B (BoNT/B-LC) inhibited evoked release at both phasic and tonic synapses and cleaved VAMP; however, neither BoNT/D-LC nor tetanus neurotoxin (TeNT-LC) were effective in these conditions. The susceptibility of VAMP to only BoNT/B-LC indicated that SNARE complexes at both phasic and tonic synapses were partially zippered only at the N-terminal end to approximately the zero-layer with the C-terminal end exposed under resting state. Therefore, the existence of the same partially zippered state of the trans-SNARE complex at both phasic and tonic synapses indicates that release probability is not determined solely by the zippered state of the trans-SNARE complex at least to the zero-layer. PMID:24747882

  9. [Oscillatory processes in microlymphatic bed of human skin].

    PubMed

    Krupatkin, A I

    2014-01-01

    Laser Doppler flowmetry with wavelet-analysis of oscillations in microlymphocirculation was used for the first time at 30 persons with (n = 17) and without edema (n = 13) of the upper extremities distal parts. Human skin microlymphatic flow is characterized by well-defined predomination of pacemaker phasic oscillations in frequency range from 0.021 Hz to 0.042 Hz (palmar surface of finger distal phalange) or from 0.016 Hz to 0.035 Hz (forearm skin). Edema was accompanied by increase of average peak frequencies and normalized maximum amplitudes of phasic oscillations (A(l)/M(l), where A(l)--average maximum amplitude of phasic oscillations, M(l)--value of average lymphatic flow, both in perfusion units). Myogenic, endothelial and respiratory low amplitude oscillations were registered rarely. Heart rate rhythms were not revealed in lymphatic flow. Intercommunications were not found between values of A(l)/M(l) and skin temperature. Only in physiologic conditions without edema negative correlation was revealed between values of A(l)/M(l) and amplitudes of myogenic oscillations in blood flow; the latter reflect the number of open capillaries and the activity of oxidative metabolism. Intercommunications were not found between lymphatic and blood flow oscillations in edema availability. Normalized amplitudes and frequencies of phasic oscillations may serve as effective diagnostic indices in micro-lymphocirculation study.

  10. Dopaminergic circuitry and risk/reward decision making: implications for schizophrenia.

    PubMed

    Stopper, Colin M; Floresco, Stan B

    2015-01-01

    Abnormal reinforcement learning and representations of reward value are present in schizophrenia, and these impairments can manifest as deficits in risk/reward decision making. These abnormalities may be due in part to dopaminergic dysfunction within cortico-limbic-striatal circuitry. Evidence from studies with laboratory animal have revealed that normal DA activity within different nodes of these circuits is critical for mediating dissociable processes that can refine decision biases. Moreover, both phasic and tonic dopamine transmission appear to play separate yet complementary roles in these processes. Tonic dopamine release within the prefrontal cortex and nucleus accumbens, serves as a "running rate-meter" of reward and reflects contextual information such as reward uncertainty and overt choice behavior. On the other hand, manipulations of outcome-related phasic dopamine bursts and dips suggest these signals provide rapid feedback to allow for quick adjustments in choice as reward contingencies change. The lateral habenula is a key input to the DA system that phasic signals is necessary for expressing subjective decision biases; as suppression of activity within this nucleus leads to catastrophic impairments in decision making and random patterns of choice behavior. As schizophrenia is characterized by impairments in using positive and negative feedback to appropriately guide decision making, these findings suggest that these deficits in these processes may be mediated, at least in part, by abnormalities in both tonic and phasic dopamine transmission. PMID:25406370

  11. Control of Vertebrate Respiration and Locomotion: A Brief Account.

    ERIC Educational Resources Information Center

    Feldman, Jack L.; Grillner, Sten

    1983-01-01

    Areas considered in this discussion include: activation/modulation of movement; control of motoneuronal discharge by excitation/inhibition; neural generation of movement synergies (considering interaction of central/peripheral elements, phasic gating of reflex effects, and neuronal organization of central pattern generators); protean nature of…

  12. Recognition and Treatment of Nerve Agent Casualties: Evidence of Reduced Learner Engagement During Video-based Training.

    PubMed

    Bukoski, Alex; Uhlich, Rindi; Tucker, Johnny; Cooper, Chris; Barnes, Steve

    2016-05-01

    Changes in electrodermal activity (EDA) correlate with arousal and stress during stimulating experiences. We hypothesized that associations exist between short-term performance gains and changes in EDA. A total of 187 combat medics were randomly assigned to simulation (S), live tissue (L), or video (V) based training in the recognition and treatment of nerve agent casualties. Change in EDA from baseline to training was quantified for tonic and phasic responses and was categorized as positive (>+10%), no change (±10%), or negative (<-10%). Cognitive and psychomotor skills assessments were applied before and after the baseline/training period to quantify short-term performance changes. Statistically significant differences in both EDA arousal measures between training modalities (p < 0.001 with L > S ∼ V) were observed. Notably, larger proportions of trainees experienced negative changes in tonic (67%) and phasic (21%) EDA measures in the V group when compared to the L and S groups. Regardless of training modality, negative tonic and phasic EDA responses were associated with lower psychomotor performance gains and this finding approached statistical significance (tonic: p = 0.056, phasic: p = 0.08). No significant differences were noted in pre- to post-training cognitive performance between EDA response categories. As quantified by EDA response to training, reduced arousal was associated with lower short-term psychomotor, but not cognitive, performance gains. PMID:27168569

  13. Stimulus-Dependent Dopamine Release in Attention-Deficit/Hyperactivity Disorder

    ERIC Educational Resources Information Center

    Sikstrom, Sverker; Soderlund, Goran

    2007-01-01

    Attention-deficit/hyperactivity disorder (ADHD) is related to an attenuated and dysfunctional dopamine system. Normally, a high extracellular dopamine level yields a tonic dopaminergic input that down-regulates stimuli-evoked phasic dopamine responses through autoreceptors. Abnormally low tonic extracellular dopamine in ADHD up-regulates the…

  14. Reading Practices in the Juvenile Correctional Facility Setting: Incarcerated Adolescents Speak Out

    ERIC Educational Resources Information Center

    Wexler, Jade; Reed, Deborah K.; Sturges, Keith

    2015-01-01

    This multi-phasic, qualitative study explored the perceptions and provision of research-based reading instruction in the juvenile correctional facility setting. In three settings in two states, we interviewed students (n = 17), teachers (n = 5), and administrators (n = 3); and conducted two focus groups (n = 8), student surveys (n = 49), and seven…

  15. Component Processes in Task Switching.

    ERIC Educational Resources Information Center

    Meiran, Nachshon; Chorev, Ziv; Sapir, Ayelet

    2000-01-01

    Studied task switching in 4 experiments involving 111 Israeli undergraduates. Results show the preparation for a task switch is not a by-product of general preparation by phasic alertness or predicting target onset and establish reconfiguration as a separate preparatory process. Suggests that there are at least three components of task switching…

  16. Testing the Behavioral Interaction and Integration of Attentional Networks

    ERIC Educational Resources Information Center

    Fan, Jin; Gu, Xiaosi; Guise, Kevin G.; Liu, Xun; Fossella, John; Wang, Hongbin; Posner, Michael I.

    2009-01-01

    One current conceptualization of attention subdivides it into functions of alerting, orienting, and executive control. Alerting describes the function of tonically maintaining the alert state and phasically responding to a warning signal. Automatic and voluntary orienting are involved in the selection of information among multiple sensory inputs.…

  17. 40 CFR 761.269 - Sampling liquid PCB remediation waste.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Sampling liquid PCB remediation waste... with § 761.61(a)(2) § 761.269 Sampling liquid PCB remediation waste. (a) If the liquid is single phase... liquid is multi-phasic, separate the phases, and collect and analyze a sample from each liquid...

  18. 40 CFR 761.269 - Sampling liquid PCB remediation waste.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Sampling liquid PCB remediation waste... with § 761.61(a)(2) § 761.269 Sampling liquid PCB remediation waste. (a) If the liquid is single phase... liquid is multi-phasic, separate the phases, and collect and analyze a sample from each liquid...

  19. 40 CFR 761.269 - Sampling liquid PCB remediation waste.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Sampling liquid PCB remediation waste... with § 761.61(a)(2) § 761.269 Sampling liquid PCB remediation waste. (a) If the liquid is single phase... liquid is multi-phasic, separate the phases, and collect and analyze a sample from each liquid...

  20. 40 CFR 761.269 - Sampling liquid PCB remediation waste.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Sampling liquid PCB remediation waste... with § 761.61(a)(2) § 761.269 Sampling liquid PCB remediation waste. (a) If the liquid is single phase... liquid is multi-phasic, separate the phases, and collect and analyze a sample from each liquid...

  1. 40 CFR 761.269 - Sampling liquid PCB remediation waste.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Sampling liquid PCB remediation waste... with § 761.61(a)(2) § 761.269 Sampling liquid PCB remediation waste. (a) If the liquid is single phase... liquid is multi-phasic, separate the phases, and collect and analyze a sample from each liquid...

  2. The Rate of Change of Vergence-Accommodation Conflict Affects Visual Discomfort

    PubMed Central

    Kane, David; Banks, Martin S.

    2014-01-01

    Stereoscopic (S3D) displays create conflicts between the distance to which the eyes must converge and the distance to which the eyes must accommodate. Such conflicts require the viewer to overcome the normal coupling between vergence and accommodation, and this effort appears to cause viewer discomfort. Vergence-accommodation coupling is driven by the phasic components of the underlying control systems, and those components respond to relatively fast changes in vergence and accommodative stimuli. Given the relationship between phasic changes and vergence-accommodation coupling, we examined how the rate of change in the vergence-accommodation conflict affects viewer discomfort. We used a stereoscopic display that allows independent manipulation of the stimuli to vergence and accommodation. We presented stimuli that simulate natural viewing (i.e., vergence and accommodative stimuli changed together) and stimuli that simulate S3D viewing (i.e., vergence stimulus changes but accommodative stimulus remains fixed). The changes occurred at 0.01, 0.05, or 0.25Hz. The lowest rate is too slow to stimulate the phasic components while the highest rate is well within the phasic range. The results were consistent with our expectation: somewhat greater discomfort was experienced when stimulus distance changed rapidly, particularly in S3D viewing when the vergence stimulus changed but the accommodative stimulus did not. These results may help in the generation of guidelines for the creation and viewing of stereo content with acceptable viewer comfort. PMID:25448713

  3. Label-Free Imaging of Dynamic and Transient Calcium Signaling in Single Cells.

    PubMed

    Lu, Jin; Li, Jinghong

    2015-11-01

    Cell signaling consists of diverse events that occur at various temporal and spatial scales, ranging from milliseconds to hours and from single biomolecules to cell populations. The pathway complexities require the development of new techniques that detect the overall signaling activities and are not limited to quantifying a single event. A plasmonic-based electrochemical impedance microscope (P-EIM) that can provide such data with excellent temporal and spatial resolution and does not require the addition of any labels for detection has now been developed. The highly dynamic and transient calcium signaling activities at the early stage of G-protein-coupled receptor (GPCR) stimulation were thus studied. It could be shown that a subpopulation of cells is more responsive towards agonist stimulation, and the heterogeneity of the local distributions and the transient activities of the ion channels during agonist-activated calcium flux in single HeLa cells were investigated.

  4. Histone H4 Lys 20 methyltransferase SET8 promotes androgen receptor-mediated transcription activation in prostate cancer

    SciTech Connect

    Yao, Lushuai; Li, Yanyan; Du, Fengxia; Han, Xiao; Li, Xiaohua; Niu, Yuanjie; Ren, Shancheng; Sun, Yingli

    2014-07-18

    Highlights: • Dihydrotestosterone stimulates H4K20me1 enrichment at the PSA promoter. • SET8 promotes AR-mediated transcription activation. • SET8 interacts with AR and promotes cell proliferation. - Abstract: Histone methylation status in different lysine residues has an important role in transcription regulation. The effect of H4K20 monomethylation (H4K20me1) on androgen receptor (AR)-mediated gene transcription remains unclear. Here we show that AR agonist stimulates the enrichment of H4K20me1 and SET8 at the promoter of AR target gene PSA in an AR dependent manner. Furthermore, SET8 is crucial for the transcription activation of PSA. Co-immunoprecipitation analyses demonstrate that SET8 interacts with AR. Therefore, we conclude that SET8 is involved in AR-mediated transcription activation, possibly through its interaction with AR and H4K20me1 modification.

  5. The role of Ca(2+) activated Cl(-) channels in blood pressure control.

    PubMed

    Matchkov, Vladimir V; Boedtkjer, Donna M; Aalkjaer, Christian

    2015-04-01

    Ca(2+)-activated Cl(-) channels (CaCCs) have numerous functions in the body and are potential players in the control of blood pressure. The CaCCs represent a heterologous group including at least two protein families; TMEM16 and bestrophins. CaCCs expression has been shown in the kidney, the heart and blood vessels. Agonist-stimulated Ca(2+)-activated Cl(-) current is important for secretion in kidney epithelia, generation of a repolarizing current in the heart and amplification of excitation-contraction coupling in vascular smooth muscle cells. Changes in CaCC expression are shown in association with hypertension, kidney cysts, sudden cardiac death and arrhythmias. This review discusses recent advances in studies concerning the role of CaCC for blood pressure control with focus on the kidney, the heart and blood vessels.

  6. Regulation of pyruvate dehydrogenase kinase expression by the farnesoid X receptor

    SciTech Connect

    Savkur, Rajesh S.; Bramlett, Kelli S.; Michael, Laura F.; Burris, Thomas P. . E-mail: burris_thomas_p@lilly.com

    2005-04-01

    The pyruvate dehydrogenase complex (PDC) functions as an important junction in intermediary metabolism by influencing the utilization of fat versus carbohydrate as a source of fuel. Activation of PDC is achieved by phosphatases, whereas, inactivation is catalyzed by pyruvate dehydrogenase kinases (PDKs). The expression of PDK4 is highly regulated by the glucocorticoid and peroxisome proliferator-activated receptors. We demonstrate that the farnesoid X receptor (FXR; NR1H4), which regulates a variety of genes involved in lipoprotein metabolism, also regulates the expression of PDK4. Treatment of rat hepatoma cells as well as human primary hepatocytes with FXR agonists stimulates the expression of PDK4 to levels comparable to those obtained with glucocorticoids. In addition, treatment of mice with an FXR agonist significantly increased hepatic PDK4 expression, while concomitantly decreasing plasma triglyceride levels. Thus, activation of FXR may suppress glycolysis and enhance oxidation of fatty acids via inactivation of the PDC by increasing PDK4 expression.

  7. Agonist induced constitutive receptor activation as a novel regulatory mechanism. Mu receptor regulation.

    PubMed

    Sadée, W; Wang, Z

    1995-01-01

    We propose the hypothesis that certain G protein coupled receptors can become constitutively activated during agonist stimulation so that the receptor remains active even after the agonist is removed. This new paradigm of receptor regulation may account for some long term effects of neurotransmitters and hormones. We have tested the hypothesis that constitutive mu receptor activation represents a crucial step driving narcotic tolerance and dependence. Our results indeed support the conversion of mu to a constitutively active state, mu*, observed in neuroblastoma SK-N-SH and SH-SY5Y tissue culture, in U293 cells transfected with the mu receptor gene, and in vivo. Constitutive mu activation may result from receptor phosphorylation to yield mu*, and further, in vivo studies indicate that formation of mu* could account for narcotic tolerance and dependence.

  8. Rathke's cleft cyst as a cause of growth hormone deficiency and micropenis.

    PubMed

    Setian, N; Aguiar, C H; Galvão, J A; Crivellaro, C E; Dichtchekenian, V; Damiani, D

    1999-05-01

    Rathke's cleft cyst has rarely been reported in pediatric patients, and such cysts are usually found by chance, in 2-33% of routine necropsies, as they have not interfered with pituitary function. In general, they are intrasellar with a single layer of ciliated cuboidal or columnar epithelium containing mucoid material. The age range in which symptomatic Rathke's cleft cysts occur is between 30 and 60 years. This paper reports an 8.1-year-old boy presenting with growth hormone deficiency and micropenis attributable to hypogonadotropic hypogonadism (HH), implying altered pituitary function since intrauterine life. At this age (before puberty) the diagnosis of HH can be made by means of the LHRH agonist stimulation test, since conventional LHRH is not able to discriminate HH from a normal prepubertal child. To our knowledge, this is the first case of micropenis caused by Rathke's cleft cyst interfering with gonadotropin and growth hormone secretion since intrauterine life.

  9. Inward spread of activation in frog muscle fibres investigated by means of high-speed microcinematography

    PubMed Central

    Sugi, H.

    1974-01-01

    1. Single fast muscle fibres of the frog were locally activated by applying current pulses to a pipette whose tip was in contact with the fibre surface, and the resulting local contractions were recorded with a high-speed ciné-camera at 1000-3000 frames/sec. 2. In some but not all of the fibres examined, a moderate membrane depolarization of 20-30 mV initiated a phasic type of local contraction, which showed a definite threshold and relaxed spontaneously while the depolarization still continued. 3. The phasic contraction was sometimes followed by a smaller steady contraction, which lasted as long as the depolarization went on and was regarded to be indentical with the graded type of local contraction. 4. With pipettes of 20-40 μm diameter, the phasic contraction was first initiated at the depolarized fibre surface, and spread to some extent inwards with a velocity of 0·7-2 cm/sec at 18-26° C. The velocity of inward spread of contraction had a Q10 of about 2·3. 5. With larger pipettes of more than 50-60 μm diameter, the phasic response was first initiated at the inner part definitely distant from the fibre surface, and the extent of contraction was greater at this part than at the superficial part during the course of the response. Furthermore, with depolarizations of nearly the threshold value, the steady contraction following the phasic one was seen only at the inner part, suggesting the reversal of the gradient of depolarization along the T tubules. 6. The phasic contraction spread inwards or transversely with a considerable decrement. The response spreading across the whole diameter of the fibre could be observed only in some cases. 7. The phasic response was not always sensitive to tetrodotoxin or to the removal of external sodium ions. 8. These results not only give information about the nature of the regenerative mechanism within the T system, but also suggest that the organization of the T tubule network is such that the electrotonic depolarization

  10. Agonist-specific behaviour of the intracellular Ca2+ response in rat hepatocytes.

    PubMed Central

    Chatton, J Y; Cao, Y; Stucki, J W

    1997-01-01

    A variety of agonists stimulate in hepatocytes a response that takes the shape of repetitive cytosolic free Ca2+ transients called Ca2+ oscillations. The shape of spikes and the pattern of oscillations in a given cell differ depending on the agonist of the phosphoinositide pathway that is applied. In this study, the response of individual rat hepatocytes to maximal stimulation by arginine vasopressin (AVP), phenylephrine and ADP was investigated by fluorescence microscopy and flash photolysis. Hepatocytes loaded with Ca2+-sensitive probes were stimulated with a first agonist to evoke a maximal response, and then a second agonist was added. When phenylephrine or ADP was used as the first agonist, AVP applied subsequently could elicit an additional response, which did not happen when AVP was first applied and phenylephrine or ADP was applied later. Cells microinjected with caged myo-inositol 1,4,5-trisphosphate (IP3) were challenged with the different agonists and, when a maximal response was obtained, photorelease of IP3 was triggered. Cells maximally stimulated with AVP did not respond to IP3 photorelease, whereas those stimulated with phenylephrine or ADP responded with a fast Ca2+ spike above the elevated steady-state level, which was followed by an undershoot. In contrast, with all three agonists, IP3 photorelease triggered at the top of an oscillatory Ca2+ transient was able to mobilize additional Ca2+. These experiments indicate that the differential response of cells to agonists is found not only during Ca2+ oscillations but also during maximal agonist stimulation and that potency and efficacy differences exist among agonists. PMID:9371717

  11. Cardiac β2-Adrenergic Receptor Phosphorylation at Ser355/356 Regulates Receptor Internalization and Functional Resensitization

    PubMed Central

    Zhao, Ru; Zheng, Qingqing; Li, Lan; Yang, Wenbing; Ding, Lu; Xue, Feng; Fan, Junming; Gong, Yongsheng

    2016-01-01

    Previous studies have demonstrated that β2-adrenergic receptors (β2ARs) can be phosphorylated by G protein-coupled receptor kinases (GRKs) and protein kinase A (PKA), affecting β2AR internalization and desensitization. However, the exact physiological function of β2ARs in cardiomyocytes is unknown. In this study, we showed that neonatal mouse cardiomyocytes had different contraction and internalization responses to sustained or repeated, transient agonist stimulation. Specifically, short-time stimulation (10 min) with epinephrine or norepinephrine increased the cardiomyocyte contraction rate, reaching a maximum at 5 min, followed by a slow decline. When the agonist was re-added after a 60-min wash-out period, the increase in the cardiomyocyte contraction rate was similar to the initial response. In contrast, when cardiomyocytes were exposed continuously to epinephrine or norepinephrine for 60 min, the second agonist stimulation did not increase the contraction response. These results indicated that continuous β2AR stimulation caused functional desensitization. Phosphorylation of β2ARs at serine (Ser)355/356 GRK phosphorylation sites, but not at Ser345/346 PKA phosphorylation sites increased with continuous epinephrine stimulation for 60 min. Accordingly, β2AR internalization increased. Interestingly, β2AR internalization was blocked by mutations at the GRK phosphorylation sites, but not by mutations at the PKA phosphorylation sites. Furthermore, inhibition of β2AR dephosphorylation by okadaic acid, a phosphatase 2A inhibitor, impaired the recovery of internalized β2ARs and reduced the cardiomyocyte contraction rate in response to epinephrine. Finally, epinephrine treatment induced the physical interaction of β-arrestin with internalized β2ARs in cardiomyocytes. Together, these data revealed the essential role of the Ser355/356 phosphorylation status of β2ARs in regulating receptor internalization and physiological resensitization in neonatal

  12. Identification of distinct c-terminal domains of the Bombyx adipokinetic hormone receptor that are essential for receptor export, phosphorylation and internalization.

    PubMed

    Huang, Haishan; Deng, Xiaoyan; He, Xiaobai; Yang, Wen; Li, Guo; Shi, Ying; Shi, Liangen; Mei, Lijuan; Gao, Jimin; Zhou, Naiming

    2011-09-01

    Neuropeptides of the adipokinetic hormone (AKH) family play important roles in insect hemolymph sugar homeostasis, larval lipolysis and storage-fat mobilization. Our previous studies have shown that the adipokinetic hormone receptor (AKHR), a Gs-coupled receptor, induces intracellular cAMP accumulation, calcium mobilization and ERK1/2 phosphorylation upon agonist stimulation. However, the underlying molecular mechanisms that regulate the internalization and desensitization of AKHR remain largely unknown. In the current study we made a construct to express AKHR fused with enhanced green fluorescent protein (EGFP) at its C-terminal end to further characterize AKHR internalization. In stable AKHR-EGFP-expressing HEK-293 cells, AKHR-EGFP was mainly localized at the plasma membrane and was rapidly internalized in a dose- and time-dependent manner via the clathrin-coated pit pathway upon agonist stimulation, and internalized receptors were slowly recovered to the cell surface after the removal of AKH peptides. The results derived from RNA interference and arrestin translocation demonstrated that G protein-coupled receptor kinase 2 and 5 (GRK2/5) and β-arrestin2 were involved in receptor phosphorylation and internalization. Furthermore, experiments using deletion and site-directed mutagenesis strategies identified the three residues (Thr356, Ser359 and Thr362) responsible for GRK-mediated phosphorylation and internalization and the C-terminal domain from residue-322 to residue-342 responsible for receptor export from ER. This is the first detailed investigation of the internalization and trafficking of insect G protein-coupled receptors.

  13. Cholinergic agonists transactivate EGFR and stimulate MAPK to induce goblet cell secretion.

    PubMed

    Kanno, Harumi; Horikawa, Yoshitaka; Hodges, Robin R; Zoukhri, Driss; Shatos, Marie A; Rios, Jose D; Dartt, Darlene A

    2003-04-01

    Conjunctival goblet cells are the primary source of mucins in the mucous layer, the innermost layer of the tear film. Conjunctival goblet cell mucin secretion is under neural control because exogenous addition of parasympathetic agonists stimulates goblet cell secretion. To elucidate the intracellular signal pathways used by cholinergic agonists to stimulate goblet cell mucin secretion, we determined whether p42/p44 mitogen-activated protein kinase (MAPK) is activated during cholinergic agonist-stimulated mucin secretion. Rat conjunctiva was removed, preincubated with or without antagonists, and stimulated with the cholinergic agonist carbachol (10(-4) M). Carbachol statistically significantly stimulated the phosphorylation of MAPK in a time- and concentration-dependent manner. U-0126, an inhibitor of MAPK activation, completely inhibited both the activation of MAPK and goblet cell secretion stimulated by carbachol. The M(1) muscarinic antagonist pirenzepine, the M(2) muscarinic antagonist gallamine, and the M(1)/M(3) muscarinic receptor antagonist N-(3-chloropropyl)-4-piperidinyl diphenylacetate (4-DAMP) also inhibited carbachol-stimulated MAPK activation. Increasing the intracellular Ca(2+) concentration with a Ca(2+) ionophore increased MAPK activation, and chelation of extracellular Ca(2+) inhibited carbachol-stimulated activation. Carbachol also increased tyrosine phosphorylation of Pyk2, p60Src, and the epidermal growth factor receptor (EGFR). The Src inhibitor PP1 and the EGFR inhibitor AG-1478 completely inhibited carbachol-stimulated MAPK activation. AG-1478 also inhibited goblet cell secretion. We conclude that carbachol transactivates the EGFR to activate MAPK, leading to conjunctival goblet cell secretion. In addition, carbachol also activates Pyk2 and p60Src that could play a role in the transactivation of the EGFR.

  14. [(35)S]GTPγS binding and opioid tolerance and efficacy in mouse spinal cord.

    PubMed

    Madia, Priyanka A; Navani, Dipesh M; Yoburn, Byron C

    2012-03-01

    The present study examined efficacy of a series of opioid agonists and then using chronic in vivo treatment protocols, determined tolerance to opioid agonist stimulated [(35)S]GTPγS (guanosine 5'-O-(3-[(35)S] thio)triphosphate) binding in mouse spinal cord membranes and compared it directly to spinal analgesic tolerance. The [(35)S]GTPγS binding assay was used to estimate efficacy (E(max) and τ; Operational Model of Agonism) of a series of opioid agonists for G-protein activation in mouse spinal cord. The rank order of opioid agonist efficacy determined in the [(35)S]GTPγS assay using the Operational Model and E(max) was similar. These efficacy estimates correlated with historical analgesic efficacy estimates. For tolerance studies, mice were continuously treated s.c. for 7days with morphine, oxycodone, hydromorphone, etorphine or fentanyl and [(35)S]GTPγS studies were conducted in spinal cord membranes. Other mice were tested in i.t. analgesia dose response studies (tailflick). Tolerance to DAMGO ([D-Ala(2),N-MePhe(4),Gly-ol(5)]enkephalin) or morphine stimulated [(35)S]GTPγS binding (decrease in E(max)) was observed following etorphine and fentanyl treatment only. These treatment protocols downregulate μ-opioid receptor density whereas morphine, oxycodone and hydromorphone do not. Spinal analgesic tolerance was observed following all treatment protocols examined (morphine, oxycodone and etorphine). Opioid antagonist treatment that specifically upregulates (chronic naltrexone) or downregulates (clocinnamox) μ-opioid receptor density produced a corresponding change in opioid agonist stimulated [(35)S]GTPγS binding. Although receptor downregulation and G-protein uncoupling are among potential mechanisms of opioid tolerance, the present results suggest that uncoupling in mouse spinal cord plays a minor role and that the [(35)S]GTPγS assay is particularly responsive to changes in μ-opioid receptor density. PMID:22108651

  15. Possible Role of α1-Antitrypsin in Endometriosis-Like Grafts From a Mouse Model of Endometriosis.

    PubMed

    Tamura, Kazuhiro; Takashima, Haruka; Fumoto, Keiko; Kajihara, Takeshi; Uchino, Satomi; Ishihara, Osamu; Yoshie, Mikihiro; Kusama, Kazuya; Tachikawa, Eiichi

    2015-09-01

    Previous study indicated that bleeding into the peritoneum may accelerate inflammatory response in endometriosis-like grafts in mice. To identify changes in protein levels in the grafts from mice that underwent unilateral ovariectomy (uOVX), which causes bleeding from ovarian arteries and vein, the grafts were generated by injecting a suspension of human endometrial cells in BALB/c nude female mice, and protein profile changes were compared with non-uOVX control mice. The level of α1-antitrypsin (α1-AT) decreased in grafts from nude mice that underwent uOVX. The levels of phosphorylated Akt, mammalian target of rapamycin, S6K, regulatory factors for cell survival, and of phosphorylated nuclear factor κB, an inflammatory mediator, were higher in endometriosis-like grafts from the uOVX group than from the control. The grafts were mostly comprised of stromal cells. The bioactivity of α1-AT was assessed by investigating cytokine expression in protease-activated receptor (PAR) 1/2 agonists-stimulated stromal cells. The PARs promoted the expression of interleukin 8 (IL-8), but treatment with α1-AT blocked IL-8 expression dose dependently. Knocking down α1-AT expression increased the constitutive IL-6, IL-8, and cyclooxygenase 2 expression as well as PAR1 agonist-stimulated IL-6 expression. These findings support the notion that decreased α1-AT protein in the grafts constituted with human endometrial cells in mice may have exacerbated inflammation in endometriosis-like grafts, suggesting the possible involvement of α1-AT in the pathophysiology of endometriosis.

  16. Cardiac β2-Adrenergic Receptor Phosphorylation at Ser355/356 Regulates Receptor Internalization and Functional Resensitization.

    PubMed

    Fan, Xiaofang; Gu, Xuejiang; Zhao, Ru; Zheng, Qingqing; Li, Lan; Yang, Wenbing; Ding, Lu; Xue, Feng; Fan, Junming; Gong, Yongsheng; Wang, Yongyu

    2016-01-01

    Previous studies have demonstrated that β2-adrenergic receptors (β2ARs) can be phosphorylated by G protein-coupled receptor kinases (GRKs) and protein kinase A (PKA), affecting β2AR internalization and desensitization. However, the exact physiological function of β2ARs in cardiomyocytes is unknown. In this study, we showed that neonatal mouse cardiomyocytes had different contraction and internalization responses to sustained or repeated, transient agonist stimulation. Specifically, short-time stimulation (10 min) with epinephrine or norepinephrine increased the cardiomyocyte contraction rate, reaching a maximum at 5 min, followed by a slow decline. When the agonist was re-added after a 60-min wash-out period, the increase in the cardiomyocyte contraction rate was similar to the initial response. In contrast, when cardiomyocytes were exposed continuously to epinephrine or norepinephrine for 60 min, the second agonist stimulation did not increase the contraction response. These results indicated that continuous β2AR stimulation caused functional desensitization. Phosphorylation of β2ARs at serine (Ser)355/356 GRK phosphorylation sites, but not at Ser345/346 PKA phosphorylation sites increased with continuous epinephrine stimulation for 60 min. Accordingly, β2AR internalization increased. Interestingly, β2AR internalization was blocked by mutations at the GRK phosphorylation sites, but not by mutations at the PKA phosphorylation sites. Furthermore, inhibition of β2AR dephosphorylation by okadaic acid, a phosphatase 2A inhibitor, impaired the recovery of internalized β2ARs and reduced the cardiomyocyte contraction rate in response to epinephrine. Finally, epinephrine treatment induced the physical interaction of β-arrestin with internalized β2ARs in cardiomyocytes. Together, these data revealed the essential role of the Ser355/356 phosphorylation status of β2ARs in regulating receptor internalization and physiological resensitization in neonatal

  17. Ambroxol-induced modification of ion transport in human airway Calu-3 epithelia.

    PubMed

    Hasegawa, Isao; Niisato, Naomi; Iwasaki, Yoshinobu; Marunaka, Yoshinori

    2006-05-01

    Ambroxol is often used as a mucolytic agent in various lung diseases. However, it is unclear how ambroxol acts on bronchial epithelial cells. To clarify the action of ambroxol, we studied the effects of ambroxol on the ion transport in human Calu-3 cells, a human submucosal serous cell line, measuring the transepithelial short-circuit current and conductance across monolayers of Calu-3 cells. Ambroxol of 100 microM diminished the terbutaline (a beta2-adrenergic agonist)-stimulated Cl-/HCO3(-)-dependent secretion without any decreases in the conductance of cystic fibrosis transmembrane conductance regulator (CFTR) channel locating on the apical membrane. On the other hand, under the basal (unstimulated) condition ambroxol increased the Cl(-)-dependent secretion with no significant change in the apical CFTR channel conductance and decreased the HCO3- secretion associated with a decrease in the apical CFTR channel conductance. Ambroxol had no major action on the epithelial Na+ channel (ENaC) or the ENaC-mediated Na+ absorption. These results indicate that in Calu-3 cells: (1) under the basal (unstimulated) condition ambroxol increases Cl- secretion by stimulating the entry step of Cl- and decreases HCO3- secretion by diminishing the activity of the CFTR channel and/or the Na+/HCO3(-)-dependent cotransporter, (2) under the adrenergic agonist-stimulated condition, ambroxol decreases Cl- secretion by acting on the Cl-/HCO3- exchanger, and (3) ambroxol has a more powerful action than the adrenergic agonist on the Cl-/HCO3- exchanger, leading fluid secretion to a moderately stimulated level from a hyper-stimulated level.

  18. Detection of novel intracellular agonist responsive pools of phosphatidylinositol 3,4-bisphosphate using the TAPP1 pleckstrin homology domain in immunoelectron microscopy.

    PubMed

    Watt, Stephen A; Kimber, Wendy A; Fleming, Ian N; Leslie, Nick R; Downes, C Peter; Lucocq, John M

    2004-02-01

    PtdIns(3,4) P (2), a breakdown product of the lipid second messenger PtdIns(3,4,5) P (3), is a key signalling molecule in pathways controlling various cellular events. Cellular levels of PtdIns(3,4) P (2) are elevated upon agonist stimulation, mediating downstream signalling pathways by recruiting proteins containing specialized lipid-binding modules, such as the pleckstrin homology (PH) domain. A recently identified protein, TAPP1 (tandem-PH-domain-containing protein 1), has been shown to interact in vitro with high affinity and specificity with PtdIns(3,4) P (2) through its C-terminal PH domain. In the present study, we have utilized this PH domain tagged with glutathione S-transferase (GST-TAPP1-PH) as a probe in an on-section immunoelectron microscopy labelling procedure, mapping the subcellular distribution of PtdIns(3,4) P (2). As expected, we found accumulation of PtdIns(3,4) P (2) at the plasma membrane in response to the agonists platelet-derived growth factor and hydrogen peroxide. Importantly, however, we also found agonist stimulated PtdIns(3,4) P (2) labelling of intracellular organelles, including the endoplasmic reticulum and multivesicular endosomes. Expression of the 3-phosphatase PTEN (phosphatase and tensin homologue deleted on chromosome 10) in PTEN-null U87MG cells revealed differential sensitivity of these lipid pools to the enzyme. These data suggest a role for PtdIns(3,4) P (2) in endomembrane function.

  19. Dihydromunduletone Is a Small-Molecule Selective Adhesion G Protein-Coupled Receptor Antagonist.

    PubMed

    Stoveken, Hannah M; Bahr, Laura L; Anders, M W; Wojtovich, Andrew P; Smrcka, Alan V; Tall, Gregory G

    2016-09-01

    Adhesion G protein-coupled receptors (aGPCRs) have emerging roles in development and tissue maintenance and is the most prevalent GPCR subclass mutated in human cancers, but to date, no drugs have been developed to target them in any disease. aGPCR extracellular domains contain a conserved subdomain that mediates self-cleavage proximal to the start of the 7-transmembrane domain (7TM). The two receptor protomers, extracellular domain and amino terminal fragment (NTF), and the 7TM or C-terminal fragment remain noncovalently bound at the plasma membrane in a low-activity state. We recently demonstrated that NTF dissociation liberates the 7TM N-terminal stalk, which acts as a tethered-peptide agonist permitting receptor-dependent heterotrimeric G protein activation. In many cases, natural aGPCR ligands are extracellular matrix proteins that dissociate the NTF to reveal the tethered agonist. Given the perceived difficulty in modifying extracellular matrix proteins to create aGPCR probes, we developed a serum response element (SRE)-luciferase-based screening approach to identify GPR56/ADGRG1 small-molecule inhibitors. A 2000-compound library comprising known drugs and natural products was screened for GPR56-dependent SRE activation inhibitors that did not inhibit constitutively active Gα13-dependent SRE activation. Dihydromunduletone (DHM), a rotenoid derivative, was validated using cell-free aGPCR/heterotrimeric G protein guanosine 5'-3-O-(thio)triphosphate binding reconstitution assays. DHM inhibited GPR56 and GPR114/ADGRG5, which have similar tethered agonists, but not the aGPCR GPR110/ADGRF1, M3 muscarinic acetylcholine, or β2 adrenergic GPCRs. DHM inhibited tethered peptide agonist-stimulated and synthetic peptide agonist-stimulated GPR56 but did not inhibit basal activity, demonstrating that it antagonizes the peptide agonist. DHM is a novel aGPCR antagonist and potentially useful chemical probe that may be developed as a future aGPCR therapeutic. PMID:27338081

  20. Dual pathways of internalization of the cholecystokinin receptor

    PubMed Central

    1995-01-01

    Receptor molecules play a major role in the desensitization of agonist- stimulated cellular responses. For G protein-coupled receptors, rapid desensitization occurs via receptor phosphorylation, sequestration, and internalization, yet the cellular compartments in which these events occur and their interrelationships are unclear. In this work, we focus on the cholecystokinin (CCK) receptor, which has been well characterized with respect to phosphorylation. We have used novel fluorescent and electron-dense CCK receptor ligands and an antibody to probe receptor localization in a CCK receptor-bearing CHO cell line. In the unstimulated state, receptors were diffusely distributed over the plasmalemma. Agonist occupation stimulated endocytosis via both clathrin-dependent and independent pathways. The former was predominant, leading to endosomal and lysosomal compartments, as well as recycling to the plasmalemma. The clathrin-independent processes led to a smooth vesicular compartment adjacent to the plasmalemma resembling caveolae, which did not transport ligand deeper within the cell. Potassium depletion largely eliminated clathrin-dependent endocytosis, while not interfering with agonist-stimulated receptor movement into subplasmalemmal smooth vesicle compartments. These cellular endocytic events can be related to the established cycle of CCK receptor phosphorylation and dephosphorylation, which we have previously described (Klueppelberg, U. G., L. K. Gates, F. S. Gorelick, and L. J. Miller. 1991. J. Biol. Chem. 266:2403-2408; Lutz, M. P., D. I. Pinon, L. K. Gates, S. Shenolikar, and L. J. Miller. 1993. J. Biol. Chem. 268:12136-12142). The rapid onset and peak of receptor phosphorylation after agonist occupation correlates best with a plasmalemmal localization, while stimulated receptor phosphatase activity correlates best with receptor residence in intracellular compartments. We postulate that the smooth vesicular compartment adjacent to the plasmalemma functions for

  1. Selective inhibition of agonist-induced but not shear stress-dependent release of endothelial autacoids by thapsigargin.

    PubMed Central

    Macarthur, H.; Hecker, M.; Busse, R.; Vane, J. R.

    1993-01-01

    1. The effects of the Ca(2+)-ATPase inhibitor, thapsigargin, on the shear stress-dependent and on the agonist-stimulated release of endothelium-derived relaxing factor, i.e. nitric oxide (NO), and prostacyclin (PGI2) were studied in bovine and human cultured endothelial cells as well as in endothelium-intact arterial segments of the rabbit. 2. Preincubation with thapsigargin (1 microM for 10 min) had no effect on the shear stress-dependent release of NO from bovine aortic endothelial cells grown on beads, but abolished the release of NO induced by ADP, bradykinin, ionomycin or poly-L-lysine. Similarly, thapsigargin completely abrogated the agonist-stimulated PGI2 release from these cells, but had no effect on the shear stress-dependent release of PGI2. 3. The acetylcholine-induced release of NO from the luminally perfused thoracic aorta and femoral artery of the rabbit was suppressed by pretreatment with thapsigargin (1 microM). In contrast, thapsigargin did not affect the shear stress-dependent release of NO from the femoral artery. 4. Administration of thapsigargin to these vascular preparations or to cultured endothelial cells alone produced a substantial release of both NO and PGI2. This release declined towards previous values after washout of thapsigargin. 5. In human and bovine cultured endothelial cells, thapsigargin (1-1000 nM) caused a dose-dependent sustained rise in [Ca2+]i, an effect that was abolished in the absence of extracellular Ca2+. Stimulation of these cells with bradykinin, histamine, ADP or ionomycin after previous exposure to thapsigargin (30-1000 nM) no longer caused an increase in [Ca2+]i.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:8428199

  2. Activation of T84 cell chloride channels by carbachol involves a phosphoinositide-coupled muscarinic M3 receptor.

    PubMed

    Dickinson, K E; Frizzell, R A; Sekar, M C

    1992-04-10

    Muscarinic agonists stimulate Cl- secretion across monolayers of the colon tumor epithelial cell line, T84. The muscarinic receptor has been characterized in T84 cell homogenates by radioligand binding using [3H]N-methylscopolamine ([3H]NMS). [3H]NMS bound to a single population of sites at 25 degrees C in 100 mM NaCl, 20 mM HEPES, 10 mM MgCl2, pH 7.4 buffer, with calculated Kd = 278 (+/- 44) pM and Bmax = 40 (+/- 6) fmol/mg protein (n = 4). Binding was reversible (diss. t1/2 = 18 +/- 3 min) and stereoselective (dexetimide Ki = 0.3 nM) much greater than levetimide (Ki = 8300 nM). Antagonists exhibited the following rank order of potencies and Ki values (nM): atropine (0.54) greater than 4-diphenylacetoxy-N-methylpiperidine methobromide (4-DAMP) (0.84) greater than dicyclomine (14) = hexahydrosiladifenidol (18) greater than pirenzepine (136) greater than AF-DX 116 (3610). The same sequence was observed for inhibition of carbachol-induced 125I efflux from T84 monolayers. This is indicative of an M3 'glandular' muscarinic receptor. Coupling to second messenger systems was examined by labelling monolayers with [14C]arachidonic acid (AA) or [3H]inositol. Carbachol (0.3 mM) did not release [14C]AA from labelled lipids, but ionomycin produced a dose-dependent increase in media [14C]AA. Carbachol (0.3 mM) elevated inositol monophosphate 14-fold. The results suggest that muscarinic agonists stimulate Cl- secretion by interacting with an M3 receptor coupled to inositide lipid hydrolysis. PMID:1379932

  3. [(35)S]GTPγS binding and opioid tolerance and efficacy in mouse spinal cord.

    PubMed

    Madia, Priyanka A; Navani, Dipesh M; Yoburn, Byron C

    2012-03-01

    The present study examined efficacy of a series of opioid agonists and then using chronic in vivo treatment protocols, determined tolerance to opioid agonist stimulated [(35)S]GTPγS (guanosine 5'-O-(3-[(35)S] thio)triphosphate) binding in mouse spinal cord membranes and compared it directly to spinal analgesic tolerance. The [(35)S]GTPγS binding assay was used to estimate efficacy (E(max) and τ; Operational Model of Agonism) of a series of opioid agonists for G-protein activation in mouse spinal cord. The rank order of opioid agonist efficacy determined in the [(35)S]GTPγS assay using the Operational Model and E(max) was similar. These efficacy estimates correlated with historical analgesic efficacy estimates. For tolerance studies, mice were continuously treated s.c. for 7days with morphine, oxycodone, hydromorphone, etorphine or fentanyl and [(35)S]GTPγS studies were conducted in spinal cord membranes. Other mice were tested in i.t. analgesia dose response studies (tailflick). Tolerance to DAMGO ([D-Ala(2),N-MePhe(4),Gly-ol(5)]enkephalin) or morphine stimulated [(35)S]GTPγS binding (decrease in E(max)) was observed following etorphine and fentanyl treatment only. These treatment protocols downregulate μ-opioid receptor density whereas morphine, oxycodone and hydromorphone do not. Spinal analgesic tolerance was observed following all treatment protocols examined (morphine, oxycodone and etorphine). Opioid antagonist treatment that specifically upregulates (chronic naltrexone) or downregulates (clocinnamox) μ-opioid receptor density produced a corresponding change in opioid agonist stimulated [(35)S]GTPγS binding. Although receptor downregulation and G-protein uncoupling are among potential mechanisms of opioid tolerance, the present results suggest that uncoupling in mouse spinal cord plays a minor role and that the [(35)S]GTPγS assay is particularly responsive to changes in μ-opioid receptor density.

  4. Calmodulin and calcium interplay in the modulation of TRPC5 channel activity. Identification of a novel C-terminal domain for calcium/calmodulin-mediated facilitation.

    PubMed

    Ordaz, Benito; Tang, Jisen; Xiao, Rui; Salgado, Alfonso; Sampieri, Alicia; Zhu, Michael X; Vaca, Luis

    2005-09-01

    TRPC5 forms Ca2+-permeable nonselective cation channels important for neurite outgrowth and growth cone morphology of hippocampal neurons. Here we studied the activation of mouse TRPC5 expressed in Chinese hamster ovary and human embryonic kidney 293 cells by agonist stimulation of several receptors that couple to the phosphoinositide signaling cascade and the role of calmodulin (CaM) on the activation. We showed that exogenous application of 10 microM CaM through patch pipette accelerated the agonist-induced channel activation by 2.8-fold, with the time constant for half-activation reduced from 4.25 +/- 0.4 to 1.56 +/- 0.85 min. We identified a novel CaM-binding site located at the C terminus of TRPC5, 95 amino acids downstream from the previously determined common CaM/IP3R-binding (CIRB) domain for all TRPC proteins. Deletion of the novel CaM-binding site attenuated the acceleration in channel activation induced by CaM. However, disruption of the CIRB domain from TRPC5 rendered the channel irresponsive to agonist stimulation without affecting the cell surface expression of the channel protein. Furthermore, we showed that high (>5 microM) intracellular free Ca2+ inhibited the current density without affecting the time course of TRPC5 activation by receptor agonists. These results demonstrated that intracellular Ca2+ has dual and opposite effects on the activation of TRPC5. The novel CaM-binding site is important for the Ca2+/CaM-mediated facilitation, whereas the CIRB domain is critical for the overall response of receptor-induced TRPC5 channel activation.

  5. Parasympathetic depression of vas deferens contraction in the guinea-pig involves adenosine receptors.

    PubMed Central

    Kurokawa, M; Tsunoo, A

    1988-01-01

    1. In the guinea-pig pelvic plexus-vas deferens preparation, stimulation of the parasympathetic pelvic nerves contracted the vas deferens then depressed the contractile responses to stimulation of the sympathetic hypogastric nerves. 2. The contraction caused by stimulation of the pelvic nerves was initially phasic then tonic. The contractions were almost abolished by application of hexamethonium to the plexus. The phasic contraction was abolished by alpha,beta-methylene adenosine triphosphate applied to the vas deferens. 3. Conditioning stimulation of the pelvic nerves preferentially depressed the phasic component of test contractions evoked by hypogastric nerve stimulation but did not affect the compound action potentials in postganglionic nerves evoked by test stimulation. 4. When the pelvic plexus was divided into two parts, one with the pelvic nerves and the other with the hypogastric nerves, conditioning stimulation of the pelvic nerves still depressed test contractions evoked by hypogastric nerve stimulation. 5. In the de-ganglionated vas deferens preparation, conditioning stimulation of some postganglionic nerves also depressed contractions evoked by test stimulation of the other postganglionic nerves. 6. 8-Phenyltheophylline (5-20 microM) applied to the vas deferens antagonized the conditioning stimulation-induced depression in both the pelvic plexus-vas deferens and the de-ganglionated preparations. 7. N6-Cyclohexyladenosine (CHA) and N6-(L-2-phenylisopropyl)-adenosine at 0.5 microM preferentially inhibited phasic contractions evoked by the postganglionic nerve stimulation. The effect of CHA was antagonized by 8-phenyltheophylline (10 microM). 8. The results indicate that the mechanism underlying the conditioning stimulation-induced depression of phasic contractions operates not in the ganglia, but through activation of adenosine receptors in the vas deferens. PMID:3256614

  6. Differential Modulation of Reinforcement Learning by D2 Dopamine and NMDA Glutamate Receptor Antagonism

    PubMed Central

    Klein, Tilmann A.; Ullsperger, Markus

    2014-01-01

    The firing pattern of midbrain dopamine (DA) neurons is well known to reflect reward prediction errors (PEs), the difference between obtained and expected rewards. The PE is thought to be a crucial signal for instrumental learning, and interference with DA transmission impairs learning. Phasic increases of DA neuron firing during positive PEs are driven by activation of NMDA receptors, whereas phasic suppression of firing during negative PEs is likely mediated by inputs from the lateral habenula. We aimed to determine the contribution of DA D2-class and NMDA receptors to appetitively and aversively motivated reinforcement learning. Healthy human volunteers were scanned with functional magnetic resonance imaging while they performed an instrumental learning task under the influence of either the DA D2 receptor antagonist amisulpride (400 mg), the NMDA receptor antagonist memantine (20 mg), or placebo. Participants quickly learned to select (“approach”) rewarding and to reject (“avoid”) punishing options. Amisulpride impaired both approach and avoidance learning, while memantine mildly attenuated approach learning but had no effect on avoidance learning. These behavioral effects of the antagonists were paralleled by their modulation of striatal PEs. Amisulpride reduced both appetitive and aversive PEs, while memantine diminished appetitive, but not aversive PEs. These data suggest that striatal D2-class receptors contribute to both approach and avoidance learning by detecting both the phasic DA increases and decreases during appetitive and aversive PEs. NMDA receptors on the contrary appear to be required only for approach learning because phasic DA increases during positive PEs are NMDA dependent, whereas phasic decreases during negative PEs are not. PMID:25253860

  7. A biologically plausible embodied model of action discovery.

    PubMed

    Bolado-Gomez, Rufino; Gurney, Kevin

    2013-01-01

    During development, animals can spontaneously discover action-outcome pairings enabling subsequent achievement of their goals. We present a biologically plausible embodied model addressing key aspects of this process. The biomimetic model core comprises the basal ganglia and its loops through cortex and thalamus. We incorporate reinforcement learning (RL) with phasic dopamine supplying a sensory prediction error, signalling "surprising" outcomes. Phasic dopamine is used in a cortico-striatal learning rule which is consistent with recent data. We also hypothesized that objects associated with surprising outcomes acquire "novelty salience" contingent on the predicability of the outcome. To test this idea we used a simple model of prediction governing the dynamics of novelty salience and phasic dopamine. The task of the virtual robotic agent mimicked an in vivo counterpart (Gancarz et al., 2011) and involved interaction with a target object which caused a light flash, or a control object which did not. Learning took place according to two schedules. In one, the phasic outcome was delivered after interaction with the target in an unpredictable way which emulated the in vivo protocol. Without novelty salience, the model was unable to account for the experimental data. In the other schedule, the phasic outcome was reliably delivered and the agent showed a rapid increase in the number of interactions with the target which then decreased over subsequent sessions. We argue this is precisely the kind of change in behavior required to repeatedly present representations of context, action and outcome, to neural networks responsible for learning action-outcome contingency. The model also showed cortico-striatal plasticity consistent with learning a new action in basal ganglia. We conclude that action learning is underpinned by a complex interplay of plasticity and stimulus salience, and that our model contains many of the elements for biological action discovery to take place.

  8. Effect of potassium and acetylcholine on canine intestinal smooth muscle.

    PubMed

    Hara, Y; Szurszewski, J H

    1986-03-01

    Mechanical and intracellular electrical activity were recorded simultaneously from small intestinal smooth muscle of the dog. Tonic and phasic contractions due to exogenous acetylcholine and elevated external K+ concentration were spike-dependent in longitudinal and inner circular muscle layers and spike-independent in the outer circular muscle layer. Voltage-tension curves were generated by graded depolarization of the membrane. In spike-dependent longitudinal and inner circular muscle layers the threshold voltage for initiation of spikes and contraction was approximately --53 mV. In spike-independent outer circular muscle layer the voltage threshold for contraction was approximately -42 mV. The resting membrane potential in longitudinal and inner circular muscle layers was close to the voltage threshold for initiation of spikes and contraction. In contrast, in the outer circular muscle it was approximately 20 mV more negative to the voltage threshold for contraction. In the outer circular muscle layer of whole-thickness preparations an increase in the amplitude of phasic contractions caused by acetylcholine was associated with an increase in the amplitude of the slow waves. Tone was related to the resting membrane potential. In preparations of isolated outer circular muscle acetylcholine caused depolarization of the membrane potential, slow waves and phasic contractions; comparable depolarization by increases in external K+ concentration did not induce slow waves or phasic contractions. Comparison of the effect of acetylcholine on outer circular muscle with the voltage-tension curve for this muscle layer showed that the top of the slow wave was associated with just the contractile force predicted by the voltage-tension curve. This suggests that acetylcholine altered the force of phasic contraction of the outer circular muscle through a voltage-dependent mechanism. In non-neural cells located on the serosal side of the outer circular muscle layer of the dog, cat

  9. A biologically plausible embodied model of action discovery

    PubMed Central

    Bolado-Gomez, Rufino; Gurney, Kevin

    2012-01-01

    During development, animals can spontaneously discover action-outcome pairings enabling subsequent achievement of their goals. We present a biologically plausible embodied model addressing key aspects of this process. The biomimetic model core comprises the basal ganglia and its loops through cortex and thalamus. We incorporate reinforcement learning (RL) with phasic dopamine supplying a sensory prediction error, signalling “surprising” outcomes. Phasic dopamine is used in a cortico-striatal learning rule which is consistent with recent data. We also hypothesized that objects associated with surprising outcomes acquire “novelty salience” contingent on the predicability of the outcome. To test this idea we used a simple model of prediction governing the dynamics of novelty salience and phasic dopamine. The task of the virtual robotic agent mimicked an in vivo counterpart (Gancarz et al., 2011) and involved interaction with a target object which caused a light flash, or a control object which did not. Learning took place according to two schedules. In one, the phasic outcome was delivered after interaction with the target in an unpredictable way which emulated the in vivo protocol. Without novelty salience, the model was unable to account for the experimental data. In the other schedule, the phasic outcome was reliably delivered and the agent showed a rapid increase in the number of interactions with the target which then decreased over subsequent sessions. We argue this is precisely the kind of change in behavior required to repeatedly present representations of context, action and outcome, to neural networks responsible for learning action-outcome contingency. The model also showed cortico-striatal plasticity consistent with learning a new action in basal ganglia. We conclude that action learning is underpinned by a complex interplay of plasticity and stimulus salience, and that our model contains many of the elements for biological action discovery to take

  10. The actions of isoprenaline and mirabegron in the isolated whole rat and guinea pig bladder.

    PubMed

    Persyn, Sara; De Wachter, Stefan; Wyndaele, Jean-Jacques; Eastham, Jane; Gillespie, James

    2016-07-01

    β3-adrenoceptor agonists influence overactive bladder in humans and animal models. However, data is emerging that the mode of action of these drugs is complex. The present study explored the actions of the β3-adrenergic agonist mirabegron and the non-selective agonist isoprenaline on the contractile systems in the rat and guinea pig bladder. Intravesical pressure was measured in isolated whole bladders from female adult animals. In both species spontaneous contractile activity was observed. The muscarinic agonist arecaidine produced complex responses consisting of an initial transient pressure rise followed by complex phasic activity. Three contractile elements were identified: intrinsic micro-contractile activity, initial transient response and steady state phasic activity. The intrinsic and steady state activity could be further divided into a baseline pressure with superimposed phasic activity. The effects of isoprenaline and mirabegron were investigated on these elements. In the rat, the micro-contractile activity could be completely inhibited by isoprenaline (full agonist). The arecaidine-induced initial and steady state baseline pressures were partially reduced, while the phasic activity was little affected. In the guinea pig, both the arecaidine-induced baseline pressure and the phasic activity were affected by isoprenaline. Mirabegron didn't produce significant inhibitory effects in any of the contractile elements in either species. These results show that complex contractile systems operate in the rat and guinea pig bladder that can be modulated by β1/β2-adrenoceptor mechanisms. No evidence was obtained for any β3-dependent regulation of contraction. These data support similar data in humans. Therefore the primary site of therapeutic action of β3-adrenergic agonists remains unknown.

  11. Induction of expression and phosphorylation of heat shock protein B5 (CRYAB) in rat myometrium during pregnancy and labour.

    PubMed

    Nicoletti, J G; White, B G; Miskiewicz, E I; MacPhee, D J

    2016-07-01

    During pregnancy the myometrium undergoes a programme of differentiation induced by endocrine, cellular, and biophysical inputs. Small heat shock proteins (HSPs) are a family of ten (B1-B10) small-molecular-weight proteins that not only act as chaperones, but also assist in processes such as cytoskeleton rearrangements and immune system activation. Thus, it was hypothesized that HSPB5 (CRYAB) would be highly expressed in the rat myometrium during the contractile and labour phases of myometrial differentiation when such processes are prominent. Immunoblot analysis revealed that myometrial CRYAB protein expression significantly increased from day (D) 15 to D23 (labour; P<0.05). In correlation with these findings, serine 59-phosphorylated (pSer59) CRYAB protein expression significantly increased from D15 to D23, and was also elevated 1-day post-partum (P<0.05). pSer59-CRYAB was detected in the cytoplasm of myocytes within both uterine muscle layers mid- to late-pregnancy. In unilaterally pregnant rats, pSer59-CRYAB protein expression was significantly elevated in the gravid uterine horns at both D19 and D23 of gestation compared with non-gravid horns. Co-immunolocalization experiments using the hTERT-human myometrial cell line and confocal microscopy demonstrated that pSer59-CRYAB co-localized with the focal adhesion protein FERMT2 at the ends of actin filaments as well as with the exosomal marker CD63. Overall, pSer59-CRYAB is highly expressed in myometrium during late pregnancy and labour and its expression appears to be regulated by uterine distension. CRYAB may be involved in the regulation of actin filament dynamics at focal adhesions and could be secreted by exosomes as a prelude to involvement in immune activation in the myometrium. PMID:27107034

  12. Integrin β1 regulates leiomyoma cytoskeletal integrity and growth

    PubMed Central

    Malik, Minnie; Segars, James; Catherino, William H.

    2014-01-01

    Uterine leiomyomas are characterized by an excessive extracellular matrix, increased mechanical stress, and increased active RhoA. Previously, we observed that mechanical signaling was attenuated in leiomyoma, but the mechanisms responsible remain unclear. Integrins, especially integrin β1, are transmembrane adhesion receptors that couple extracellular matrix stresses to the intracellular cytoskeleton to influence cell proliferation and differentiation. Here we characterized integrin and laminin to signaling in leiomyoma cells. We observed a 2.25 ± 0.32 fold increased expression of integrin β1 in leiomyoma cells, compared to myometrial cells. Antibody-mediated inhibition of integrin β1 led to significant growth inhibition in leiomyoma cells and a loss of cytoskeletal integrity. Specifically, polymerization of actin filaments and formation of focal adhesions were reduced by inhibition of integrin p1. Inhibition of integrin β1 in leiomyoma cells led to 0.81 ± 0.02 fold decrease in active RhoA, and resembled levels found in serum-starved cells. Likewise, inhibition of integrin β1 was accompanied by a decrease in phospho-ERK. Compared to myometrial cells, leiomyoma cells demonstrated increased expression of integrin α6 subunit to laminin receptor (1.91 ± 0.11 fold), and increased expression of laminin 5α (1.52±0.02), laminin 5β (3.06±0.92), and laminin 5γ (1.66 ± 0.06). Of note, leiomyoma cells grown on laminin matrix appear to realign themselves. Taken together, the findings reveal that the attenuated mechanical signaling in leiomyoma cells is accompanied by an increased expression and a dependence on integrin β1 signaling in leiomyoma cells, compared to myometrial cells. PMID:23023061

  13. Intracellular angiotensin II activates rat myometrium.

    PubMed

    Deliu, Elena; Tica, Andrei A; Motoc, Dana; Brailoiu, G Cristina; Brailoiu, Eugen

    2011-09-01

    Angiotensin II is a modulator of myometrial activity; both AT(1) and AT(2) receptors are expressed in myometrium. Since in other tissues angiotensin II has been reported to activate intracellular receptors, we assessed the effects of intracellular administration of angiotensin II via microinjection on myometrium, using calcium imaging. Intracellular injection of angiotensin II increased cytosolic Ca(2+) concentration ([Ca(2+)](i)) in myometrial cells in a dose-dependent manner. The effect was abolished by the AT(1) receptor antagonist losartan but not by the AT(2) receptor antagonist PD-123319. Disruption of the endo-lysosomal system, but not that of Golgi apparatus, prevented the angiotensin II-induced increase in [Ca(2+)](i). Blockade of AT(1) receptor internalization had no effect, whereas blockade of microautophagy abolished the increase in [Ca(2+)](i) produced by intracellular injection of angiotensin II; this indicates that microautophagy is a critical step in transporting the peptide into the endo-lysosomes lumenum. The response to angiotensin II was slightly reduced in Ca(2+)-free saline, indicating a major involvement of Ca(2+) release from internal stores. Blockade of inositol 1,4,5-trisphosphate (IP(3)) receptors with heparin and xestospongin C or inhibition of phospholipase C (PLC) with U-73122 abolished the response to angiotensin II, supporting the involvement of PLC-IP(3) pathway. Angiotensin II-induced increase in [Ca(2+)](i) was slightly reduced by antagonism of ryanodine receptors. Taken together, our results indicate for the first time that in myometrial cells, intracellular angiotensin II activates AT(1)-like receptors on lysosomes and activates PLC-IP(3)-dependent Ca(2+) release from endoplasmic reticulum; the response is further augmented by a Ca(2+)-induced Ca(2+) release mechanism via ryanodine receptors activation.

  14. [An Examination for Uterine Dynamic Study with Phase-sensitive Inversion-recovery].

    PubMed

    Takatsu, Yasuo; Motegi, Shunichi; Miyati, Tosiaki; Yamamura, Kenichirou

    2016-01-01

    The depth of myometrial invasion in patients with endometrial carcinoma is recognized as an important factor that closely correlates with prognosis. Preoperative assessment of myometrial invasion is essential for planning surgery. To enhance the contrast between myometrium and endometrium including myometrial invasion with endometrial carcinoma, we optimized the sequence parameter with phase-sensitive inversion-recovery (PSIR) in gadolinium dynamic study of uterine corpus. On a 1.5-T magnetic resonance imaging (MRI), images were acquired by three-dimensional (3D) T1 -turbo field echo (TFE) with PSIR sequence and gadolinium-diethylenetriamine pentaacetic acid( Gd-DTPA) diluted phantom (0-5 mmol/L) and myometrium model (manganese chloride tetrahydrate+agar). We calculated the null point and the contrast-to-noise ratio (CNR) at multiple TFE inversion delay times, 200 ms-maximum in each combination; flip angles (FAs), 5-35 degrees; TFE factor, 20-40; and shot interval (SI), 500-1000 ms. We assumed that dynamic scanning time was 30 seconds when the sensitivity encoding factor was 2, namely, in this study, the scanning time was 1 minute with no sensitivity encoding. In addition, we compared CNR between optimized PSIR sequence ande-Thrive. We recognized a successful CNR of the 3D PSIR parameter was TFE inversion delay times, 335 ms; FA, 25 degrees; TFE factor, 20; and SI, 500 ms. In each gadolinium-DTPA diluted phantom, the average CNR of the optimized PSIR sequence was approximately 1.7 times (maximum: 3 times) higher than e-Thrive. Optimizing sequence parameter of PSIR is applicable in gadolinium dynamic study of uterine corpus.

  15. Mechanical stretch regulates hypertrophic phenotype of the myometrium during pregnancy.

    PubMed

    Shynlova, Oksana; Kwong, Ruth; Lye, Stephen J

    2010-01-01

    The adaptive growth of the uterus is a critical event that involves changes in cellular phenotypes throughout pregnancy. In early pregnancy, uterine growth is due to hyperplasia of uterine smooth muscle cells (SMCs) within the myometrium; however, the major component of myometrial growth occurs after mid-gestation. This study sought to test the hypothesis that increase in myometrial growth seen during late pregnancy is due to SMC hypertrophy caused by mechanical stretch of uterine tissue by a growing fetus(es) by providing direct measurements of individual SMC size. We employed a stereological approach to calculate the average cell volumes of uterine myocytes through diameter measurements using the Stereoinvestigator statistical software. Uterine tissues were collected from nonpregnant Wistar rats, as well as from gravid and nongravid horns of unilaterally pregnant animals on gestational days (d) 8 (early gestation), 14 (mid-gestation), 19 (late gestation), 22 (term), and 4 days post partum. Anti-caveolin-1 immunostaining was used to clearly delineate SMC boundaries. The stereological analysis revealed that the dramatic increase in myometrial growth seen during late gestation (d19-22) is due to a threefold increase in the size of uterine myocytes. A significant increase in SMC volumes was detected in the gravid uterine horn as compared with the corresponding empty horn of unilateral term pregnant animals (day 22, mean cell volume 1114 vs 361 microm(3), P<0.05), indicating the effect of uterine occupancy. The restriction of the hypertrophy to cells within the gravid horn suggests that it may be a response to the biological mechanical stretch of uterine walls by the growing fetus(es) and placenta(s).

  16. Identification of pluripotent cells in bovine uterus: in situ and in vitro studies.

    PubMed

    Łupicka, Martyna; Bodek, Gabriel; Shpigel, Nahum; Elnekave, Ehud; Korzekwa, Anna J

    2015-04-01

    The aim of this study was to identify uterine pluripotent cells both in bovine uterine tissues as well in epithelial, stromal, and myometrial uterine cell populations. Moreover, the relationship of pluripotent markers expression with age and the uterine horn side was considered. Uterine tissue was collected from ipsilateral and contralateral horns (days 8-10 of the estrous cycle). Immunohistostaining for C-KIT, OCT3/4, NANOG, and SOX2 in uterine tissue was determined. mRNA expression of C-KIT, OCT3/4, NANOG and SOX2 was evaluated in uterine tissue relative to the age of the cow and uterine horn side. Gene and protein expression of these markers in the uterine luminal epithelial, stromal, and myometrial cells was evaluated by real-time PCR and western blotting respectively. The expression of pluripotent cell markers OCT3/4, NANOG, and SOX2 was identified by flow cytometry assay in epithelial, stromal, and myometrial cells. Multilineage differentiation of the bovine uterine cells was performed. mRNA expression of OCT3/4, NANOG, and SOX2 in uterine tissue was higher in the ipsilateral horn than in the contralateral horn. Flow cytometry assay revealed positive fluorescence for OCT3/4, NANOG, and SOX2 in all uterine cell types. Results showed the age-dependent expression of pluripotent markers in uterine tissue. Beside, the different expression of pluripotent cells in each horn of uterus suggests the influence of ovarian hormones on these characteristics. The highest mRNA and protein expression for pluripotent markers was observed in stromal cells among uterine cells, which indicates this population of cells as the main site of pluripotent cells in the cow uterus.

  17. [Chorioadenoma destruens: presentation of 2 cases].

    PubMed

    Garza de la Garza, R; Livas Rodríguez, S; Ploneda González, C

    1989-06-01

    The incidence of Gestational Trophoblastic Disease varies from country to country, however, it is notable the greater frequency for developing nations. The incidence in Mexico varies from one in 144 to 625 pregnancies. The advances that have been made in the knowledge of this disease and its classification allow an integrated diagnosis and management of gestational trophoblastic disease. This report presents two cases of Chorioadenoma Destruens in which myometrial invasion was suspected from ultrasonographic studies. One case was treated with chemotherapy; the other by histerectomy following uterine perforation. The outcome was satisfactory in both cases.

  18. Effects of d- and l-limonene on the pregnant rat myometrium in vitro

    PubMed Central

    Hajagos-Tóth, Judit; Hódi, Ágnes; Seres, Adrienn B.; Gáspár, Róbert

    2015-01-01

    Aim To study the effects of d- and l-limonene on pregnant rat myometrial contractility in vitro, and investigate how these effects are modified by other agents. D- and l-limonene (10−13-10−8 M) caused myometrial contraction in a dose-dependent manner. Methods Contractions of uterine rings from 22-day-pregnant rats were measured in an organ bath in the presence of d- or l-limonene (10−13-10−8 M) and nifedipine (10−8 M), tetraethyl-ammonium (10−3 M), theophylline (10−5 M), or paxilline (10−5 M). Uterine cyclic adenosine monophosphate (cAMP) level was detected by enzyme immunoassay. Oxidative damage was induced by methylglyoxal (3 × 10−2 M) and the alteration was measured via noradrenaline (1 × 10−9 to 3 × 10−5 M) -induced contractions. Results Pre-treatment with nifedipine (10−8 M), tetraethylammonium (10−3 M), and theophylline (10−5 M) attenuated the contracting effect of d- and l-limonene, while in the presence of paxilline (10−5 M) d- and l-limonene were ineffective. The two enantiomers decreased the myometrial cAMP level, but after paxilline pretreatment the cAMP level was not altered compared with the control value. Additionally, l-limonene (10−6 M) diminished consequences of oxidative damage caused by methylglyoxal (3 × 10−2 M) on contractility, whereas d-limonene was ineffective. Conclusion Our findings suggest that l-limonene has an antioxidant effect and that both d-and l-limonene cause myometrial contraction through activation of the A2A receptor and opening of the voltage-gated Ca2+ channel. It is possible that limonene-containing products increase the pregnant uterus contractility and their use should be avoided during pregnancy. PMID:26526880

  19. Pathogenic changes of dispersion and contrast of coherent images of biotissues

    NASA Astrophysics Data System (ADS)

    Pishak, Olga V.

    2002-02-01

    The paper presents the results of polarization-correlation investigation of multifractal collagen structure of physiologically normal and pathologically changed tissues of women's reproductive sphere and of skin. The technique of polarization selection of coherent biotissues' images with the following determination of their autocorrelation functions and spectral densities is suggested. The correlation-optical criteria of early diagnostics of pathological changes' appearance of myometry (forming of the germ of fibromyoma) and of skin(psoriasis) are determined. The suggested paper is directed to investigation of the possibilities of pathological changes of biotissues' morphological structure by means of determining the polarizationally filtered autocorrelation functions (ACF) and corresponding spectral densities of their coherent images.

  20. Polarization-correlation study of biotissue multifractal structure

    NASA Astrophysics Data System (ADS)

    Olar, O. I.; Ushenko, A. G.

    2003-09-01

    This paper presents the results of polarization-correlation study of multifractal collagen structure of physiologically normal and pathologically changed tissues of women"s reproductive sphere and skin. The technique of polarization selection of coherent images of biotissues with further determination of their autocorrelation functions and spectral densities is suggested. The correlation-optical criteria of early diagnostics of appearance of pathological changes in the cases of myometry (forming the germ of fibromyoma) and skin (psoriasis) are determined. This study is directed to investigate the possibilities of recognition of pathological changes of biotissue morphological structure by determining the polarization-dependent autocorrelation functions (ACF) and corresponding spectral densities of tissue coherent images.

  1. Polarization-correlation investigation of biotissue multifractal structure and diagnostics of its pathological change

    NASA Astrophysics Data System (ADS)

    Angelsky, Oleg V.; Pishak, Vasyl P.; Ushenko, Alexander G.; Burkovets, Dimitry N.; Pishak, Olga V.

    2001-05-01

    The paper presents the results of polarization-correlation investigation of multifractal collagen structure of physiologically normal and pathologically changed tissues of women's reproductive sphere and of skin. The technique of polarization selection of coherent biotissues' images followed by determination of their autocorrelation functions and spectral densities is suggested. The correlation- optical criteria of early diagnostics of pathological changes' appearance of myometry (forming of the germ of fibromyoma) and of skin (psoriasis) are determined. The present paper examines the possibilities of diagnostics of pathological changes of biotissues' morphological structure by means of determining the polarizationally filtered autocorrelation functions (ACF) and corresponding spectral densities of their coherent images.

  2. [Meno-metrorrhagia imaging].

    PubMed

    Robert, Y; Bazot, M

    2008-01-01

    Menometrorrhagia is a frequent cause of medical consulting. After clinical examination showing the uterine origin of bleeding and excluding a cervical or vulvo-vaginal cause, ultrasonography is indicated. It is the first-line technique examination for the identification of an etiology: benign endometrium lesion (polyp, endometrium atrophy or hypertrophy) or malignant tumor, myometrial lesions (adenomyosis, leiomyoma), adnexal tumors, and first trimester pregnancy complication. Color Doppler sonography and hysterosonography are useful tools for ultrasound performance improvement. Ultrasound gives orientation for diagnosis and therapeutic strategy.

  3. Androgens in pregnancy: roles in parturition

    PubMed Central

    Makieva, Sofia; Saunders, Philippa T.K.; Norman, Jane E.

    2014-01-01

    BACKGROUND Understanding the physiology of pregnancy enables effective management of pregnancy complications that could otherwise be life threatening for both mother and fetus. A functional uterus (i) retains the fetus in utero during pregnancy without initiating stretch-induced contractions and (ii) is able to dilate the cervix and contract the myometrium at term to deliver the fetus. The onset of labour is associated with successful cervical remodelling and contraction of myometrium, arising from concomitant activation of uterine immune and endocrine systems. A large body of evidence suggests that actions of local steroid hormones may drive changes occurring in the uterine microenvironment at term. Although there have been a number of studies considering the potential role(s) played by progesterone and estrogen at the time of parturition, the bio-availability and effects of androgens during pregnancy have received less scrutiny. The aim of this review is to highlight potential roles of androgens in the biology of pregnancy and parturition. METHODS A review of published literature was performed to address (i) androgen concentrations, including biosynthesis and clearance, in maternal and fetal compartments throughout gestation, (ii) associations of androgen concentrations with adverse pregnancy outcomes, (iii) the role of androgens in the physiology of cervical remodelling and finally (iv) the role of androgens in the physiology of myometrial function including any impact on contractility. RESULTS Some, but not all, androgens increase throughout gestation in maternal circulation. The effects of this increase are not fully understood; however, evidence suggests that increased androgens might regulate key processes during pregnancy and parturition. For example, androgens are believed to be critical for cervical remodelling at term, in particular cervical ripening, via regulation of cervical collagen fibril organization. Additionally, a number of studies highlight

  4. Three-dimensional imaging of the uterus: The value of the coronal plane

    PubMed Central

    Wong, Lufee; White, Nikki; Ramkrishna, Jayshree; Júnior, Edward Araujo; Meagher, Simon; Costa, Fabricio Da Silva

    2015-01-01

    Advent in three-dimensional (3D) imaging technology has seen 3D ultrasound establish itself as a useful adjunct complementary to traditional two-dimensional imaging of the female pelvis. This advantage largely arises from its ability to reconstruct the coronal plane of the uterus, which allows further delineation of many gynecological disorders. 3D imaging of the uterus is now the preferred imaging modality for assessing congenital uterine anomalies and intrauterine device localization. Newer indications include the diagnosis of adenomyosis. It can also add invaluable information to delineate other endometrial and myometrial pathology such as fibroids and endometrial polyps. PMID:26753063

  5. Immortalization of primary human smooth muscle cells.

    PubMed Central

    Perez-Reyes, N; Halbert, C L; Smith, P P; Benditt, E P; McDougall, J K

    1992-01-01

    Primary human aortic and myometrial smooth muscle cells (SMCs) were immortalized using an amphotropic recombinant retroviral construct containing the E6 and E7 open reading frames (ORFs) of human papillomavirus type 16. The SMCs expressing the E6/E7 ORFs have considerably elevated growth rates when compared with nonimmortalized control cells and show no signs of senescence with long-term passage. The first SMC line derived in this study has been maintained in continuous tissue culture for greater than 1 year (greater than 180 population doublings). The immortalized SMCs have decreased cell size and decreased content of muscle-specific alpha-actin filaments as determined by indirect immunofluorescence. Southern blot analysis has demonstrated the stable integration of the E6/E7 ORFs in the retrovirally infected cells, and radioimmunoprecipitation has confirmed the continued expression of the E6 and E7 genes. Cytogenetic studies of the SMC lines have revealed essentially diploid populations except for the myometrial clonal line, which became aneuploid at late passage (greater than 125 doublings). These cell lines were not tumorigenic in nude mice. Images PMID:1311088

  6. Peptides PHI and VIP: comparison between vascular and nonvascular smooth muscle effect in rabbit uterus

    SciTech Connect

    Bardrum, B.; Ottesen, B.; Fahrenkrug, J.

    1986-07-01

    The distribution and effects of the two neuropeptides, vasoactive intestinal polypeptide (VIP) and peptide histidine isoleucine amide (PHI), on vascular and nonvascular smooth muscle in the urogenital tract of nonpregnant rabbit female, were investigated. Immunoreactive VIP and PHI were present in all regions except the ovary with the highest concentration in the uterin cervix. By using in vitro tension recordings of myometrial specimens, it was demonstrated that both peptides displayed a dose-dependent inhibition of the mechanical activity. The dose-response curves of VIP and PHI were superimposable with and ID50 of 3 x 10 Y mol/l, and their combined effect was additive. In addition, the influence of the two peptides on myometrial blood flow (MBF) was investigated by the xenon-133 washout technique. Both peptides were found to increase MBF with the same potency and efficacy. Their combined effect was additive. In conclusion VIP and PHI are present in the rabbit urogenital tract, and the two peptides are equipotent inhibitors of mechanical nonvascular and vascular smooth muscle activity in the uterus.

  7. Uterine type II estrogen-binding sites are not of eosinophil origin

    SciTech Connect

    Not Available

    1986-01-05

    A recent report suggested that nuclear type II sites in the rat uterus are of eosinophil origin and may represent (/sup 3/H)estradiol binding to eosinophil peroxidase. To further evaluate this hypothesis the authors examined the response of nuclear type II sites to estrogen under conditions where eosinophils are not present. Results of the experiments show that physiological levels of estradiol-17..beta.. (10 nM for 72 h) will stimulate nuclear type II sites in highly purified cultures of rat uterine stromal and myometrial cells. The magnitude of the response of type II sites to estradiol in these stromal (4-fold) and myometrial (80-fold) cell cultures was essentially identical to that observed in the uterine cell types following in vivo estrogen treatment. Since these highly purified cultures of uterine cells were prepared from the uterus of a 21-day ovariectomized rat which is devoid of eosinophils, it was concluded that estradiol stimulation of nuclear type II sites is a direct intracellular response to estrogen which occurs independent of eosinophil accumulation. Furthermore, it was found that type II sites in the rat uterus are not peroxidase. Stimulation of cytosol and nuclear type II sites by estrogen in the rat uterus is a direct intracellular response to the hormone unrelated to eosinophil accumulation and/or peroxidase activity.

  8. Diffuse Venous Malformation of the Uterus in a Pregnant Woman with Klippel-Trénaunay Syndrome Diagnosed by DCE-MRI

    PubMed Central

    Yara, Nana; Masamoto, Hitoshi; Iraha, Yuko; Wakayama, Akihiko; Chinen, Yukiko; Nitta, Hayase; Kinjo, Tadatsugu

    2016-01-01

    Background. We experienced a rare case of a pregnant woman with Klippel-Trénaunay syndrome complicated with diffuse venous malformation of the uterus. This is the first report on the usefulness of dynamic contrast-enhanced-MRI for the diagnosis of diffuse venous malformation of the uterus. Case Presentation. A 23-year-old woman presented with convulsions and talipes equinus position of both lower limbs at 11 weeks of gestation. At 27 weeks, ultrasonography demonstrated tubular echolucent spaces throughout the myometrium. Dynamic MRI at 37 weeks revealed that the myometrial lesion was enhanced slowly and showed homogeneous enhancement even on a 10 min delayed image. Taken together with unilateral foot hypertrophy, varices, and port-wine stain, the patient was diagnosed as having Klippel-Trénaunay syndrome complicated with diffuse venous malformation of the pregnant uterus. The patient underwent elective cesarean section because of severe dystonia. The lower uterine segment was thickened and heavy venous blood flow was observed at the incision. Histological diagnosis of the myometrial biopsy specimen was venous malformation. Conclusions. Both diffuse venous malformation and Klippel-Trénaunay syndrome during pregnancy can involve considerable complications, in particular, massive bleeding during labor. Women who suffer from this syndrome should be advised about the risk of complications of pregnancy. PMID:27006845

  9. Prognostic and Clinical Significance of miRNA-205 in Endometrioid Endometrial Cancer

    PubMed Central

    Wilczynski, Milosz; Wojciechowski, Michal; Malinowski, Andrzej

    2016-01-01

    Endometrial cancer is one of the most common malignancies of the reproductive female tract, with endometrioid endometrial cancer being the most frequent type. Despite the relatively favourable prognosis in cases of endometrial cancer, there is a necessity to evaluate clinical and prognostic utility of new molecular markers. MiRNAs are small, non-coding RNA molecules that take part in RNA silencing and post-transcriptional regulation of gene expression. Altered expression of miRNAs may be associated with cancer initiation, progression and metastatic capabilities. MiRNA-205 seems to be one of the key regulators of gene expression in endometrial cancer. In this study, we investigated clinical and prognostic role of miRNA-205 in endometrioid endometrial cancer. After total RNA extraction from 100 archival formalin-fixed paraffin-embedded tissues, real-time quantitative RT-PCR was used to define miRNA-205 expression levels. The aim of the study was to evaluate miRNA-205 expression levels in regard to patients’ clinical and histopathological features, such as: survival rate, recurrence rate, staging, myometrial invasion, grading and lymph nodes involvement. Higher levels of miRNA-205 expression were observed in tumours with less than half of myometrial invasion and non-advanced cancers. Kaplan-Maier analysis revealed that higher levels of miRNA-205 were associated with better overall survival (p = 0,034). These results indicate potential clinical utility of miRNA-205 as a prognostic marker. PMID:27737015

  10. [Endometrial carcinoma--stage I. Evaluation of risk and prognostic factors in an analysis of 120 cases].

    PubMed

    Romano, F M; Bruno, G; Manicastri, A M

    1991-03-01

    The Authors report on a series of 120 cases of endometrial carcinoma observed from 1980 to 1989, in the 1st Gynecological Oncology of the Oncological Hospital "M. Ascoli", Palermo. After careful clinical and pathologic review, the cases, subdivided in pre and post-menopausal groups, in order to verify possible differences between the two groups, were evaluated with reference to the principal risk factors and to some prognostic factors. As for the risk factors (old age, nulliparity, obesity, long fertile life, etc.), the data do not differ from the results in the literature. The evaluation of the prognostic indicators confirms once again the close relationship between histologic grade and myometrial invasion of the tumor. They have an important predictive value for prognosis and their knowledge is indispensable for an adequate therapeutic strategy, especially at pathologic stage I. Furthermore, findings show some delay in endometrial cancer diagnosis in the population studied, particularly in premenopausal women. Such delay turns out to be significantly associated with a greater myometrial infiltration of tumor.

  11. The inwardly rectifying K+ channel KIR7.1 controls uterine excitability throughout pregnancy.

    PubMed

    McCloskey, Conor; Rada, Cara; Bailey, Elizabeth; McCavera, Samantha; van den Berg, Hugo A; Atia, Jolene; Rand, David A; Shmygol, Anatoly; Chan, Yi-Wah; Quenby, Siobhan; Brosens, Jan J; Vatish, Manu; Zhang, Jie; Denton, Jerod S; Taggart, Michael J; Kettleborough, Catherine; Tickle, David; Jerman, Jeff; Wright, Paul; Dale, Timothy; Kanumilli, Srinivasan; Trezise, Derek J; Thornton, Steve; Brown, Pamela; Catalano, Roberto; Lin, Nan; England, Sarah K; Blanks, Andrew M

    2014-09-01

    Abnormal uterine activity in pregnancy causes a range of important clinical disorders, including preterm birth, dysfunctional labour and post-partum haemorrhage. Uterine contractile patterns are controlled by the generation of complex electrical signals at the myometrial smooth muscle plasma membrane. To identify novel targets to treat conditions associated with uterine dysfunction, we undertook a genome-wide screen of potassium channels that are enriched in myometrial smooth muscle. Computational modelling identified Kir7.1 as potentially important in regulating uterine excitability during pregnancy. We demonstrate Kir7.1 current hyper-polarizes uterine myocytes and promotes quiescence during gestation. Labour is associated with a decline, but not loss, of Kir7.1 expression. Knockdown of Kir7.1 by lentiviral expression of miRNA was sufficient to increase uterine contractile force and duration significantly. Conversely, overexpression of Kir7.1 inhibited uterine contractility. Finally, we demonstrate that the Kir7.1 inhibitor VU590 as well as novel derivative compounds induces profound, long-lasting contractions in mouse and human myometrium; the activity of these inhibitors exceeds that of other uterotonic drugs. We conclude Kir7.1 regulates the transition from quiescence to contractions in the pregnant uterus and may be a target for therapies to control uterine contractility.

  12. The Use of Clenbuterol for the Management of Large Animal Dystocias: Surgical Corrections in the Cow and Ewe

    PubMed Central

    Ménard, Laurent; Diaz, Carlos Segundo

    1987-01-01

    Clenbuterol (Ventipulmin® Solution) was included in the corrective management of dystocia cases requiring obstetrical surgery encountered in a Quebec rural practice. Data were collected on a total of 69 cases: 63 bovine and three ovine caesareans, and three bovine fetotomies. Ease of exteriorization of the gravid uterus and postoperative development of uterine adhesions were compared in two groups of bovine caesarean cases: a clenbuterol-treated group (Group A, n = 63) and a nontreated control group (Group B, n = 90). Clenbuterol produced a potent myometrial relaxant effect making its use beneficial in the correction of the bovine and ovine dystocias. It provided significantly improved uterine maneuverability (×2 = 47.63, P < 0.001) and significantly reduced postoperative development of adhesions (×2 = 14.05, P < 0.001) except in bovine caesarean cases with a high degree of myometrial distension. Neonatal and maternal health were not impaired and retention of fetal membranes was not increased. When used as directed, clenbuterol was a safe, reliable, and efficacious drug. PMID:17422865

  13. System-level biomechanical approach for the evaluation of term and preterm pregnancy maintenance.

    PubMed

    Mahmoud, Hussam; Wagoner Johnson, Amy; Chien, Edward K; Poellmann, Michael J; McFarlin, Barbara

    2013-02-01

    Preterm birth is the primary contributor to perinatal morbidity and mortality, with those born prior to 32 weeks disproportionately contributing compared to those born at 32-37 weeks. Outcomes for babies born prematurely can be devastating. Parturition is recognized as a mechanical process that involves the two processes that are required to initiate labor: rhythmic myometrial contractions and cervical remodeling with subsequent dilation. Studies of parturition tend to separate these two processes rather than evaluate them as a unified system. The mechanical property characterization of the cervix has been primarily performed on isolated cervical tissue, with an implied understanding of the contribution from the uterine corpus. Few studies have evaluated the function of the uterine corpus in the absence of myometrial contractions or in relationship to retaining the fetus. Therefore, the cervical-uterine interaction has largely been neglected in the literature. We suggest that a system-level biomechanical approach is needed to understand pregnancy maintenance. To that end, this paper has two main goals. One goal is to highlight the gaps in current knowledge that need to be addressed in order to develop any comprehensive and clinically relevant models of the system. The second goal is to illustrate the utility of finite element models in understanding pregnancy maintenance of the cervical-uterine system. The paper targets an audience that includes the reproductive biologist/clinician and the engineer/physical scientist interested in biomechanics and the system level behavior of tissues.

  14. Glutathione prevents preterm parturition and fetal death by targeting macrophage-induced reactive oxygen species production in the myometrium.

    PubMed

    Hadi, Tarik; Bardou, Marc; Mace, Guillaume; Sicard, Pierre; Wendremaire, Maeva; Barrichon, Marina; Richaud, Sarah; Demidov, Oleg; Sagot, Paul; Garrido, Carmen; Lirussi, Frédéric

    2015-06-01

    Preterm birth is an inflammatory process resulting from the massive infiltration of innate immune cells and the production of proinflammatory cytokines in the myometrium. However, proinflammatory cytokines, which induce labor in vivo, fail to induce labor-associated features in human myometrial cells (MCs). We thus aimed to investigate if reactive oxygen species (ROS) production could be the missing step between immune cell activation and MC response. Indeed, we found that ROS production is increased in the human preterm laboring myometrium (27% ROS producing cells, respectively, versus 2% in nonlaboring controls), with 90% ROS production in macrophages. Using LPS-stimulated myometrial samples and cell coculture experiments, we demonstrated that ROS production is required for labor onset. Furthermore, we showed that ROS are required first in the NADPH oxidase (NADPHox)-2/NF-κB-dependent macrophage response to inflammatory stimuli but, more importantly, to trigger macrophage-induced MCs transactivation. Remarkably, in a murine model of LPS-induced preterm labor (inducing delivery within 17 hours, with no pup survival), cotreatment with glutathione delayed labor onset up to 94 hours and prevented in utero fetal distress, allowing 46% pups to survive. These results suggest that targeting ROS production with the macrophage-permeable antioxidant glutathione could constitute a promising strategy to prevent preterm birth. PMID:25757563

  15. Uterine distension differentially affects remodelling and distensibility of the uterine vasculature in non-pregnant rats.

    PubMed

    Osol, George; Barron, Carolyn; Mandalà, Maurizio

    2012-01-01

    During pregnancy the mammalian uterine circulation undergoes significant expansive remodelling necessary for normal pregnancy outcome. The underlying mechanisms are poorly defined. The goal of this study was to test the hypothesis that myometrial stretch actively stimulates uterine vascular remodelling by developing a new surgical approach to induce unilateral uterine distension in non-pregnant rats. Three weeks after surgery, which consisted of an infusion of medical-grade silicone into the uterine lumen, main and mesometrial uterine artery and vein length, diameter and distensibility were recorded. Radial artery diameter, distensibility and vascular smooth muscle mitotic rate (Ki67 staining) were also measured. Unilateral uterine distension resulted in significant increases in the length of main uterine artery and vein and mesometrial segments but had no effect on vessel diameter or distensibility. In contrast, there were significant increases in the diameter of the radial arteries associated with the distended uterus. These changes were accompanied by reduced arterial distensibility and increased vascular muscle hyperplasia. In summary, this is the first report to show that myometrial stretch is a sufficient stimulus to induce significant remodelling of uterine vessels in non-pregnant rats. Moreover, the results indicate differential regulation of these growth processes as a function of vessel size and type.

  16. Vitamin K3 inhibits mouse uterine contraction in vitro via interference with the calcium transfer and the potassium channels.

    PubMed

    Zhang, Xian-Xia; Lu, Li-Min; Wang, Li

    2016-08-01

    Previous studies have demonstrated vitamin K3 had a great relief to smooth muscle spastic disorders, but no researches have yet pinpointed its possible anti-contractile activity in the uterus. Here, we evaluated the effect of vitamin K3 on myometrial contractility and explored the possible mechanisms of vitamin K3 action. Myograph apparatus were used to record the changes in contractility of isolated mouse uterine strips in a tissue bath. Uterine strips were exposed to vitamin K3 or vehicle. Vitamin K3 suppressed spontaneous contractions in a concentration dependent manner. It significantly decreased the contractile frequency induced by PGF2ɑ but not their amplitude (expect 58.0 μM). Prior incubation with vitamin K3 reduced the effectiveness of PGF2ɑ-induced contraction. The antispasmodic effect of vitamin K3 was also sensitive to potassium channel blockers, such as tetraethylammonium, 4-aminopyridine, iberiotoxin) but not to the nitric oxide related pathway blockers. High concentrations (29.0, 58.0 μM) of vitamin K3 weakened the Ca(2+) dose response and inhibited phase 1 contraction (intracellular stored calcium release). These dates suggest that vitamin K3 specifically suppresses myometrial contractility by affecting calcium and potassium channels; thus, this approach has potential therapy for uterine contractile activity related disorders.

  17. Expression of matrix metalloproteinase-2 and survivin in endometrioid and nonendometrioid endometrial cancers and clinicopathologic significance

    PubMed Central

    Yilmaz, Evren; Koyuncuoglu, Meral; Görken, İlknur Bilkay; Saatli, Bahadir; Ulukus, Emine Cagnur; Saygili, Ugur

    2011-01-01

    Objective To determine matrix metalloproteinase-2 and survivin expressions in endometrial cancers, their relation to clinical and histologic parameters and to investigate any difference in the expression of these markers between endometrioid and nonendometrioid cancers. Methods Ninety-five patients with endometrial cancer, were included. Matrix metalloproteinase-2 and survivin expressions were analyzed immunohistochemically from paraffin-embedded tissues by using specific monoclonal antibodies. Results Survivin nuclear expression was higher in endometrioid cancer as compared to nonendometrioid cancer (p=0.040), but there was no difference for cytoplasmic survivin and matrix metalloproteinase-2 expressions between type I and type II carcinomas. Survivin cytoplasmic staining was significantly lower in patients with deep myometrial invasion (p=0.038). Nuclear expression of survivin is decreased in histologic grade 3 tumors compared to grade 1 and 2 tumors (p=0.013), but there is no difference between grade 1 and 2. We did not find any statistically significant difference between survivin or matrix metalloproteinase-2 expressions and survival. Conclusion Survivin and matrix metalloproteinase-2 are present in endometrioid and nonendometrioid cancers. Grade 1 and 2 tumors and carcinomas having myometrial invasion less than 50% have higher survivin expression. These results supports that, survivin may play an important role in early stage tumors and early phases of tumor development. We did not find any association between matrix metalloproteinase-2 expression and classical prognostic factors in endometrial cancer and both proteins were not associated with survival. PMID:21860734

  18. Uterine contractility of plants used to facilitate childbirth in Nigerian ethnomedicine

    PubMed Central

    Attah, Alfred F.; O'Brien, Margaret; Koehbach, Johannes; Sonibare, Mubo A.; Moody, Jones O.; Smith, Terry J.; Gruber, Christian W.

    2012-01-01

    Ethnopharmacological relevance Pregnant women in Nigeria use plant preparations to facilitate childbirth and to reduce associated pain. The rationale for this is not known and requires pharmacological validation. Aim of study Obtain primary information regarding the traditional use of plants and analyze their uterine contractility at cellular level. Materials and methods Semi-structured, open interviews using questionnaires of traditional healthcare professionals and other informants triggered the collection and identification of medicinal plant species. The relative traditional importance of each medicinal plant was determined by its use-mention index. Extracts of these plants were analyzed for their uterotonic properties on an in vitro human uterine cell collagen model. Result The plants Calotropis procera, Commelina africana, Duranta repens, Hyptis suaveolens, Ocimum gratissimum, Saba comorensis, Sclerocarya birrea, Sida corymbosa and Vernonia amygdalina were documented and characterized. Aqueous extracts from these nine plants induced significant sustained increases in human myometrial smooth muscle cell contractility, with varying efficiencies, depending upon time and dose of exposure. Conclusion The folkloric use of several plant species during childbirth in Nigeria has been validated. Seven plants were for the first time characterized to have contractile properties on uterine myometrial cells. The results serve as ideal starting points in the search for safe, longer lasting, effective and tolerable uterotonic drug leads. PMID:22766472

  19. Cyclic AMP signalling pathways in the regulation of uterine relaxation

    PubMed Central

    Yuan, Wei; López Bernal, Andrés

    2007-01-01

    Studying the mechanism(s) of uterine relaxation is important and will be helpful in the prevention of obstetric difficulties such as preterm labour, which remains a major cause of perinatal mortality and morbidity. Multiple signalling pathways regulate the balance between maintaining relative uterine quiescence during gestation, and the transition to the contractile state at the onset of parturition. Elevation of intracellular cyclic AMP promotes myometrial relaxation, and thus quiescence, via effects on multiple intracellular targets including calcium channels, potassium channels and myosin light chain kinase. A complete understanding of cAMP regulatory pathways (synthesis and hydrolysis) would assist in the development of better tocolytics to delay or inhibit preterm labour. Here we review the enzymes involved in cAMP homoeostasis (adenylyl cyclases and phosphodiesterases) and possible myometrial substrates for the cAMP dependent protein kinase. We must emphasise the need to identify novel pharmacological targets in human pregnant myometrium to achieve safe and selective uterine relaxation when this is indicated in preterm labour or other obstetric complications. PMID:17570154

  20. CALIX[4]ARENE C-99 INHIBITS MYOSIN ATPase ACTIVITY AND CHANGES THE ORGANIZATION OF CONTRACTILE FILAMENTS OF MYOMETRIUM.

    PubMed

    Labyntseva, R D; Bevza, A A; Lul'ko, A O; Cherenok, S O; Kalchenko, V I; Kosterin, S O

    2015-01-01

    Calix[4]arenes are cup-like macrocyclic (polyphenolic) compounds, they are regarded as promising molecular "platforms" for the design of new physiologically active compounds. We have earlier found that calix[4]arene C-99 inhibits the ATPase activity of actomyosin and myosin subfragment-1 of pig uterus in vitro. The aim of this study was to investigate the interaction of calix[4]arene C-99 with myosin from rat uterine myocytes. It was found that the ATPase activity of myosin prepared from pre-incubated with 100 mM of calix[4]arene C-99 myocytes was almost 50% lower than in control. Additionally, we have revealed the effect of calix[4]arene C-99 on the subcellular distribution of actin and myosin in uterus myocytes by the method of confocal microscopy. This effect can be caused by reorganization of the structure of the contractile smooth muscle cell proteins due to their interaction with calix[4]arene. The obtained results demonstrate the ability of calix[4]arene C-99 to penetrate into the uterus muscle cells and affect not only the myosin ATPase activity, but also the structure of the actin and myosin filaments in the myometrial cells. Demonstrated ability of calix[4]arene C-99 can be used for development of new pharmacological agents for efficient normalization of myometrial contractile hyperfunction.

  1. Comparison of pulsatile and continuous ritodrine administration: effects on uterine contractility and beta-adrenergic receptor cascade.

    PubMed

    Caritis, S N; Chiao, J P; Kridgen, P

    1991-04-01

    In this study we compare the uterine contractility and beta-adrenergic receptor effects of identical doses of ritodrine administered intermittently or continuously for 24 hours in pregnant sheep. Ritodrine was administered intravenously to five animals as a pulse, 16 micrograms/kg every 1.5 hours, whereas five other animals received ritodrine as a continuous infusion of 0.18 microgram/kg/min. Ritodrine plasma concentrations at steady state were comparable in both groups and averaged 18 ng/ml. Animals receiving ritodrine pulses demonstrated no alteration of myometrial beta-adrenergic receptors or adenylyl cyclase activity, and ritodrine inhibited oxytocin-induced contractility comparably at 4 and 24 hours. Animals receiving ritodrine continuously had a significant decrease in myometrial beta-adrenergic receptors and adenylyl cyclase activity, yet ritodrine inhibition of oxytocin-induced uterine contractility was sustained for 24 hours. Oxytocin receptors were not affected by ritodrine administration and were similar in both groups. At the dose studied, oxytocin-induced contractions are comparably inhibited by ritodrine for 24 hours whether the drug is given continuously or in a pulsatile fashion.

  2. Vitamin K3 inhibits mouse uterine contraction in vitro via interference with the calcium transfer and the potassium channels.

    PubMed

    Zhang, Xian-Xia; Lu, Li-Min; Wang, Li

    2016-08-01

    Previous studies have demonstrated vitamin K3 had a great relief to smooth muscle spastic disorders, but no researches have yet pinpointed its possible anti-contractile activity in the uterus. Here, we evaluated the effect of vitamin K3 on myometrial contractility and explored the possible mechanisms of vitamin K3 action. Myograph apparatus were used to record the changes in contractility of isolated mouse uterine strips in a tissue bath. Uterine strips were exposed to vitamin K3 or vehicle. Vitamin K3 suppressed spontaneous contractions in a concentration dependent manner. It significantly decreased the contractile frequency induced by PGF2ɑ but not their amplitude (expect 58.0 μM). Prior incubation with vitamin K3 reduced the effectiveness of PGF2ɑ-induced contraction. The antispasmodic effect of vitamin K3 was also sensitive to potassium channel blockers, such as tetraethylammonium, 4-aminopyridine, iberiotoxin) but not to the nitric oxide related pathway blockers. High concentrations (29.0, 58.0 μM) of vitamin K3 weakened the Ca(2+) dose response and inhibited phase 1 contraction (intracellular stored calcium release). These dates suggest that vitamin K3 specifically suppresses myometrial contractility by affecting calcium and potassium channels; thus, this approach has potential therapy for uterine contractile activity related disorders. PMID:27237971

  3. Expression of matricellular proteins in human uterine leiomyomas and normal myometrium.

    PubMed

    Bogusiewicz, Michal; Semczuk, Andrzej; Juszczak, Malgorzata; Langner, Ewa; Walczak, Katarzyna; Rzeski, Wojciech; Tomaszewski, Jacek; Rechberger, Tomasz

    2012-11-01

    Growth of human leiomyomas can probably be initiated as a response to injury, in a way similar to the development of keloids. Among many bioactive molecules, which are implicated in tissue repair, a pivotal role is attributed to matricellular proteins. The aim of the current study was to evaluate the immunohistochemical expression of tenascin-C (TNC), thrombospondin-1 (TSP-1), SPARC/osteonectin and tenascin-X (TNX) in human uterine leiomyomas and normal myometrium. Immunostaining was performed on 33 pairs of paraffin-fixed sections and 9 cell-lines derived from uterine leiomyomas and normal myometrium. Fifteen (45.5%) leiomyomas investigated were positive for TNC, whereas all normal myometrial samples were immunonegative (χ²=19.41; p<0.001). Immunostaining for TSP-1 was observed in 20 (60.6%) uterine fibroids and in 12 (36.4%) control samples (χ²=3.88; p<0.05). The expression of SPARC/osteonectin protein was more frequently found in leiomyomas than in normal myometrium, but this difference was not significant. Apart from one fibroid culture and one myometrial culture, all the others revealed strong TNC immunostaining. Expression of TSP-1 and SPARC/osteonectin was weak to moderate in all established cell-lines. None of the tissues or cell lines investigated showed positive staining for TNX. In conclusion, TSP-1 and TNC are likely to play important roles in the pathogenesis of uterine leiomyomas, presumably affecting cell proliferation and/or extracellular matrix deposition.

  4. Molecular Mechanisms of Parturition

    PubMed Central

    1997-01-01

    The initial signal for triggering human parturition might be fetal but of trophoblastic origin. Concomitantly, this placental signal would have as its target not only the uterus but also the fetus by activating its hypothalamo-pituitary-adrenocortical axis. The latter would represent a second fetal signal which, at the fetomaternal interface, would amplify and define in time the mechanisms responsible for the onset of labor, implying changes in the myometrial and cervical extracellular matrix associated with the accession of the contractile phenotype for myometrial cells. At each phase of these processes in the utero-feto-placental system, the nature of these signals remains to be identified. Is there a single substance, or rather, and more likely, a combination of several? We appear to be in the presence of dynamic systems of a neuro-immuno-hormonal type which are difficult to describe. Nevertheless, steroid hormones appear to coordinate their successive equilibriums until they become irreversible. Such irreversibility constitutes the essential sign of parturition. PMID:18476161

  5. Physiological state gates acquisition and expression of mesolimbic reward prediction signals.

    PubMed

    Cone, Jackson J; Fortin, Samantha M; McHenry, Jenna A; Stuber, Garret D; McCutcheon, James E; Roitman, Mitchell F

    2016-02-16

    Phasic dopamine signaling participates in associative learning by reinforcing associations between outcomes (unconditioned stimulus; US) and their predictors (conditioned stimulus; CS). However, prior work has always engendered these associations with innately rewarding stimuli. Thus, whether dopamine neurons can acquire prediction signals in the absence of appetitive experience and update them when the value of the outcome changes remains unknown. Here, we used sodium depletion to reversibly manipulate the appetitive value of a hypertonic sodium solution while measuring phasic dopamine signaling in rat nucleus accumbens. Dopamine responses to the NaCl US following sodium depletion updated independent of prior experience. In contrast, prediction signals were only acquired through extensive experience with a US that had positive affective value. Once learned, dopamine prediction signals were flexibly expressed in a state-dependent manner. Our results reveal striking differences with respect to how physiological state shapes dopamine signals evoked by outcomes and their predictors. PMID:26831116

  6. Physiological state gates acquisition and expression of mesolimbic reward prediction signals

    PubMed Central

    Cone, Jackson J.; Fortin, Samantha M.; McHenry, Jenna A.; Stuber, Garret D.; McCutcheon, James E.; Roitman, Mitchell F.

    2016-01-01

    Phasic dopamine signaling participates in associative learning by reinforcing associations between outcomes (unconditioned stimulus; US) and their predictors (conditioned stimulus; CS). However, prior work has always engendered these associations with innately rewarding stimuli. Thus, whether dopamine neurons can acquire prediction signals in the absence of appetitive experience and update them when the value of the outcome changes remains unknown. Here, we used sodium depletion to reversibly manipulate the appetitive value of a hypertonic sodium solution while measuring phasic dopamine signaling in rat nucleus accumbens. Dopamine responses to the NaCl US following sodium depletion updated independent of prior experience. In contrast, prediction signals were only acquired through extensive experience with a US that had positive affective value. Once learned, dopamine prediction signals were flexibly expressed in a state-dependent manner. Our results reveal striking differences with respect to how physiological state shapes dopamine signals evoked by outcomes and their predictors. PMID:26831116

  7. Calcitonin Gene-Related Peptide Receptor Blocker Inhibits Spontaneous Activity of Human Ureter.

    PubMed

    Jankovic, Slobodan M; Jankovic, Snezana V; Stojadinovic, Dobrivoje; Stojadinovic, Miroslav; Djuric, Janko M; Stojic, Isidora

    2015-01-01

    Calcitonin gene-related peptide (CGRP) is present in nerve fibers that innervate the human ureter and may have important influence on the motility of this organ. The aim of our study was to investigate whether CGRP could affect the motility of an isolated human ureter. The tension and intraluminal pressure of the isolated ureteral segments were recorded and registered on a personal computer. Both phasic and tonic contractions of the isolated preparations were measured as area under the tension or pressure recordings. CGRP and CGRP fragment 8-37 were separately added to the organ baths in a cumulative way, thereby gradually increasing their concentration in the baths' solution. Alpha-CGRP did not affect either phasic, spontaneous activity or tone of isolated ureteral segments, as measured by both tension and intraluminal pressure. On the other hand, CGRP 8-37 caused concentration-dependent inhibition of spontaneous contractions of the isolated ureteral segments. PMID:26305057

  8. Methodological Gaps in Left Atrial Function Assessment by 2D Speckle Tracking Echocardiography

    PubMed Central

    Rimbaş, Roxana Cristina; Dulgheru, Raluca Elena; Vinereanu, Dragoş

    2015-01-01

    The assessment of left atrial (LA) function is used in various cardiovascular diseases. LA plays a complementary role in cardiac performance by modulating left ventricular (LV) function. Transthoracic two-dimensional (2D) phasic volumes and Doppler echocardiography can measure LA function non-invasively. However, evaluation of LA deformation derived from 2D speckle tracking echocardiography (STE) is a new feasible and promising approach for assessment of LA mechanics. These parameters are able to detect subclinical LA dysfunction in different pathological condition. Normal ranges for LA deformation and cut-off values to diagnose LA dysfunction with different diseases have been reported, but data are still conflicting, probably because of some methodological and technical issues. This review highlights the importance of an unique standardized technique to assess the LA phasic functions by STE, and discusses recent studies on the most important clinical applications of this technique. PMID:26761370

  9. Relaxation of Isolated Ventricular Cardiomyocytes by a Voltage-Dependent Process

    NASA Astrophysics Data System (ADS)

    Bridge, John H. B.; Spitzer, Kenneth W.; Ershler, Philip R.

    1988-08-01

    Cell contraction and relaxation were measured in single voltage-clamped guinea pig cardiomyocytes to investigate the contribution of sarcolemmal Na+-Ca2+ exchange to mechanical relaxation. Cells clamped from -80 to 0 millivolts displayed initial phasic and subsequent tonic contractions; caffeine reduced or abolished the phasic and enlarged the tonic contraction. The rate of relaxation from tonic contractions was steeply voltage-dependent and was significantly slowed in the absence of a sarcolemmal Na+ gradient. Tonic contractions elicited in the absence of a Na+ gradient promptly relaxed when external Na+ was applied, reflecting activation of Na+-Ca2+ exchange. It appears that a voltage-dependent Na+-Ca2+ exchange can rapidly mechanically relax mammalian heart muscle.

  10. Temporally Coordinated Deep Brain Stimulation in the Dorsal and Ventral Striatum Synergistically Enhances Associative Learning.

    PubMed

    Katnani, Husam A; Patel, Shaun R; Kwon, Churl-Su; Abdel-Aziz, Samer; Gale, John T; Eskandar, Emad N

    2016-01-01

    The primate brain has the remarkable ability of mapping sensory stimuli into motor behaviors that can lead to positive outcomes. We have previously shown that during the reinforcement of visual-motor behavior, activity in the caudate nucleus is correlated with the rate of learning. Moreover, phasic microstimulation in the caudate during the reinforcement period was shown to enhance associative learning, demonstrating the importance of temporal specificity to manipulate learning related changes. Here we present evidence that extends upon our previous finding by demonstrating that temporally coordinated phasic deep brain stimulation across both the nucleus accumbens and caudate can further enhance associative learning. Monkeys performed a visual-motor associative learning task and received stimulation at time points critical to learning related changes. Resulting performance revealed an enhancement in the rate, ceiling, and reaction times of learning. Stimulation of each brain region alone or at different time points did not generate the same effect. PMID:26725509

  11. Temporally Coordinated Deep Brain Stimulation in the Dorsal and Ventral Striatum Synergistically Enhances Associative Learning

    PubMed Central

    Katnani, Husam A.; Patel, Shaun R.; Kwon, Churl-Su; Abdel-Aziz, Samer; Gale, John T.; Eskandar, Emad N.

    2016-01-01

    The primate brain has the remarkable ability of mapping sensory stimuli into motor behaviors that can lead to positive outcomes. We have previously shown that during the reinforcement of visual-motor behavior, activity in the caudate nucleus is correlated with the rate of learning. Moreover, phasic microstimulation in the caudate during the reinforcement period was shown to enhance associative learning, demonstrating the importance of temporal specificity to manipulate learning related changes. Here we present evidence that extends upon our previous finding by demonstrating that temporally coordinated phasic deep brain stimulation across both the nucleus accumbens and caudate can further enhance associative learning. Monkeys performed a visual-motor associative learning task and received stimulation at time points critical to learning related changes. Resulting performance revealed an enhancement in the rate, ceiling, and reaction times of learning. Stimulation of each brain region alone or at different time points did not generate the same effect. PMID:26725509

  12. Correlation between tests of attention and performance on grooved and Purdue pegboards in normal subjects.

    PubMed

    Strenge, Hans; Niederberger, Uwe; Seelhorst, Ulrike

    2002-10-01

    This study investigated the relation between tests of manual dexterity and attentional functions with 49 normal, right-handed medical students (26 women, 23 men, ages 19-30 years) who were assessed with a Purdue Pegboard Test, Grooved Pegboard Test, and a Test for Attentional Performance, comprising measures of tonic and phasic alertness and divided attention. Weak to moderately high partial correlations controlling for finger size were obtained between pegboard test performance of the left hand and phasic alertness (r = .31-.50). Purdue Pegboard Assembly subtest scores were weakly correlated with divided attention (r = -.39). These findings suggest that attention is an important determinant of performance for manual dexterity tests of the nondominant hand. PMID:12434843

  13. Serotonergic neurons signal reward and punishment on multiple timescales.

    PubMed

    Cohen, Jeremiah Y; Amoroso, Mackenzie W; Uchida, Naoshige

    2015-02-25

    Serotonin's function in the brain is unclear. One challenge in testing the numerous hypotheses about serotonin's function has been observing the activity of identified serotonergic neurons in animals engaged in behavioral tasks. We recorded the activity of dorsal raphe neurons while mice experienced a task in which rewards and punishments varied across blocks of trials. We 'tagged' serotonergic neurons with the light-sensitive protein channelrhodopsin-2 and identified them based on their responses to light. We found three main features of serotonergic neuron activity: (1) a large fraction of serotonergic neurons modulated their tonic firing rates over the course of minutes during reward vs punishment blocks; (2) most were phasically excited by punishments; and (3) a subset was phasically excited by reward-predicting cues. By contrast, dopaminergic neurons did not show firing rate changes across blocks of trials. These results suggest that serotonergic neurons signal information about reward and punishment on multiple timescales.

  14. Temporally Coordinated Deep Brain Stimulation in the Dorsal and Ventral Striatum Synergistically Enhances Associative Learning.

    PubMed

    Katnani, Husam A; Patel, Shaun R; Kwon, Churl-Su; Abdel-Aziz, Samer; Gale, John T; Eskandar, Emad N

    2016-01-04

    The primate brain has the remarkable ability of mapping sensory stimuli into motor behaviors that can lead to positive outcomes. We have previously shown that during the reinforcement of visual-motor behavior, activity in the caudate nucleus is correlated with the rate of learning. Moreover, phasic microstimulation in the caudate during the reinforcement period was shown to enhance associative learning, demonstrating the importance of temporal specificity to manipulate learning related changes. Here we present evidence that extends upon our previous finding by demonstrating that temporally coordinated phasic deep brain stimulation across both the nucleus accumbens and caudate can further enhance associative learning. Monkeys performed a visual-motor associative learning task and received stimulation at time points critical to learning related changes. Resulting performance revealed an enhancement in the rate, ceiling, and reaction times of learning. Stimulation of each brain region alone or at different time points did not generate the same effect.

  15. Isolation of carotenoid-deficient mutant from alkylated dibenzothiophene desulfurizing nocardioform bacteria, Gordonia sp. TM414.

    PubMed

    Matsui, Toru; Maruhashi, Kenji

    2004-02-01

    The dibenzothiophene-desulfurizing nocardioform bacteria, Gordonia sp. TM414, was isolated from oil-contaminated soil. To avoid coloration of the oil layer after the desulfurization reaction, which could decrease the quality of the oil, two colorless knock-out mutants, TPc and TPd, were isolated by using a broad-host-range transposon complex. Genomic sequence analysis revealed that the same gene was disrupted in these mutants and that the transposon-inserted gene was assigned as the gene for phytoene desaturase, crt I. The crt I mutants also showed desulfurization activity comparable to that of the parent strain in a model-oil/aqueous bi-phasic reaction, suggesting that the carotenoid production is not responsible for the bi-phasic desulfurization reaction that requires hydrophobic substrate incorporation from the organic phase.

  16. Adaptive force generation for precision-grip lifting by a spectral timing model of the cerebellum.

    PubMed

    Ulloa, Antonio; Bullock, Daniel; Rhodes, Bradley J

    2003-01-01

    We modeled adaptive generation of precision grip forces during object lifting. The model presented adjusts reactive and anticipatory grip forces to a level just above that needed to stabilize lifted objects in the hand. The model obeys principles of cerebellar structure and function by using slip sensations as error signals to adapt phasic motor commands to tonic force generators associated with output synergies controlling grip aperture. The learned phasic commands are weight- and texture-dependent. Simulations of the new circuit model reproduce key aspects of experimental observations of force application. Over learning trials, the onset of grip force buildup comes to lead the load force buildup, and the rate-of-rise of grip force, but not load force, scales inversely with the friction of the object.

  17. The use of in-flight foot pressure as a countermeasure to neuromuscular degradation

    NASA Technical Reports Server (NTRS)

    Layne, C. S.; Mulavara, A. P.; Pruett, C. J.; McDonald, P. V.; Kozlovskaya, I. B.; Bloomberg, J. J.

    1998-01-01

    The purpose of this study was to determine whether applying foot pressure to unrestrained subjects during space flight could enhance the neuromuscular activation associated with rapid arm movements. Four men performed unilateral arm raises while wearing--or not wearing--specially designed boots during a 81- or 115-day space flight. Arm acceleration and surface EMG were obtained from selected lower limb and trunk muscles. Pearson r coefficients were used to evaluate similarity in phasic patterns between the two in-flight conditions. In-flight data also were magnitude normalized to the mean voltage value of the muscle activation waveforms obtained during the no-foot-pressure condition to facilitate comparison of activation amplitude between the two in-flight conditions. Foot pressure enhanced neuromuscular activation and somewhat modified the phasic features of the neuromuscular activation during the arm raises.

  18. Serotonergic neurons signal reward and punishment on multiple timescales.

    PubMed

    Cohen, Jeremiah Y; Amoroso, Mackenzie W; Uchida, Naoshige

    2015-01-01

    Serotonin's function in the brain is unclear. One challenge in testing the numerous hypotheses about serotonin's function has been observing the activity of identified serotonergic neurons in animals engaged in behavioral tasks. We recorded the activity of dorsal raphe neurons while mice experienced a task in which rewards and punishments varied across blocks of trials. We 'tagged' serotonergic neurons with the light-sensitive protein channelrhodopsin-2 and identified them based on their responses to light. We found three main features of serotonergic neuron activity: (1) a large fraction of serotonergic neurons modulated their tonic firing rates over the course of minutes during reward vs punishment blocks; (2) most were phasically excited by punishments; and (3) a subset was phasically excited by reward-predicting cues. By contrast, dopaminergic neurons did not show firing rate changes across blocks of trials. These results suggest that serotonergic neurons signal information about reward and punishment on multiple timescales. PMID:25714923

  19. Human anal motility while fasting, after feeding, and during sleep.

    PubMed

    Orkin, B A; Hanson, R B; Kelly, K A; Phillips, S F; Dent, J

    1991-04-01

    The aim of this study was to determine whether the human anal sphincter responds dynamically to changing physiological states. In 19 healthy human subjects, intraluminal anal canal pressure was measured with a 5-cm perfused sleeve sensor during the day while fasting (3 hours) and after feeding (3 hours) and at night during sleep (8 hours). Daytime mean anal canal pressures (+/- SEM) while fasting (50 +/- 3 mm Hg) were similar to those after feeding (49 +/- 3 mm Hg) and to those at night during sleep (49 +/- 3 mm Hg). Marked minute-to-minute variations in mean pressure occurred in all three periods, however, as did large phasic increases and decreases in pressure (greater than 20 mm Hg) and small phasic changes in pressure less than 20 mm Hg (anal slow waves). The minute-to-minute variations in mean pressure were greater during the awake fed state (4 +/- 1 mm Hg/min) than at night during sleep (2 +/- 1 mm Hg/min; P less than 0.03), as were the number of large phasic waves per minute (increases in pressure: awake, fed = 0.5 +/- 1 waves/min, night = 0.3 +/- 0.1 waves/min, P less than 0.05; decreases in pressure: awake, fed = 0.4 +/- 0.1 waves/min, night = 0.2 +/- 0.1 waves/min, P less than 0.05). Anal small waves had a similar frequency of about 17 waves/min in all three states. In conclusion, the anal sphincter maintains a continuous pressure barrier to rectal outflow both during the day and at night during sleep. However, marked minute-to-minute variations in mean pressure and large phasic increases and decreases in pressure do occur. Both are fewer at night during sleep.

  20. The general anaesthetic etomidate inhibits the excitability of mouse thalamocortical relay neurons by modulating multiple modes of GABAA receptor-mediated inhibition

    PubMed Central

    Herd, Murray B; Lambert, Jeremy J; Belelli, Delia

    2014-01-01

    Modulation of thalamocortical (TC) relay neuron function has been implicated in the sedative and hypnotic effects of general anaesthetics. Inhibition of TC neurons is mediated predominantly by a combination of phasic and tonic inhibition, together with a recently described ‘spillover’ mode of inhibition, generated by the dynamic recruitment of extrasynaptic γ-aminobutyric acid (GABA)A receptors (GABAARs). Previous studies demonstrated that the intravenous anaesthetic etomidate enhances tonic and phasic inhibition in TC relay neurons, but it is not known how etomidate may influence spillover inhibition. Moreover, it is unclear how etomidate influences the excitability of TC neurons. Thus, to investigate the relative contribution of synaptic (α1β2γ2) and extrasynaptic (α4β2δ) GABAARs to the thalamic effects of etomidate, we performed whole-cell recordings from mouse TC neurons lacking synaptic (α10/0) or extrasynaptic (δ0/0) GABAARs. Etomidate (3 μm) significantly inhibited action-potential discharge in a manner that was dependent on facilitation of both synaptic and extrasynaptic GABAARs, although enhanced tonic inhibition was dominant in this respect. Additionally, phasic inhibition evoked by stimulation of the nucleus reticularis exhibited a spillover component mediated by δ-GABAARs, which was significantly prolonged in the presence of etomidate. Thus, etomidate greatly enhanced the transient suppression of TC spike trains by evoked inhibitory postsynaptic potentials. Collectively, these results suggest that the deactivation of thalamus observed during etomidate-induced anaesthesia involves potentiation of tonic and phasic inhibition, and implicate amplification of spillover inhibition as a novel mechanism to regulate the gating of sensory information through the thalamus during anaesthetic states. PMID:24773078

  1. Deep Brain Stimulation of the Globus Pallidus Internus in the Parkinsonian Primate: Local Entrainment and Suppression of Low-Frequency Oscillations

    PubMed Central

    McCairn, Kevin W.; Turner, Robert S.

    2009-01-01

    Competing theories seek to account for the therapeutic effects of high-frequency deep brain stimulation (DBS) of the internal globus pallidus (GPi) for medically intractable Parkinson's disease. To investigate this question, we studied the spontaneous activity of 102 pallidal neurons during GPiDBS in two macaques rendered parkinsonian by administration of MPTP. Stimulation through macroelectrodes in the GPi (≥200 μA at 150 Hz for 30 s) reduced rigidity in one animal and increased spontaneous movement in both. Novel artifact subtraction methods allowed uninterrupted single-unit recording during stimulation. GPiDBS induced phasic (78% of cells) or sustained (22%) peristimulus changes in firing in both pallidal segments. A subset of cells responded at short latency (<2 ms) in a manner consistent with antidromic driving. Later phasic increases clustered at 3- to 5-ms latency. Stimulation-induced decreases were either phasic, clustered at 1–3 ms, or sustained, showing no peristimulus modulation. Response latency and magnitude often evolved over 30 s of stimulation, but responses were relatively stable by the end of that time. GPiDBS reduced mean firing rates modestly and only in GPi (−6.9 spikes/s). Surprisingly, GPiDBS had no net effect on the prevalence or structure of burst firing. GPiDBS did reduce the prevalence of synchronized low-frequency oscillations. Some cell pairs became synchronized instead at the frequency of stimulation. Suppression of low-frequency oscillations did not require high-frequency synchronization, however, or even the presence of a significant peristimulus response. In summary, the therapeutic effects of GPiDBS may be mediated by an abolition of low-frequency synchronized oscillations as a result of phasic driving. PMID:19164104

  2. Impaired excitability of renal afferent innervation after exposure to the inflammatory chemokine CXCL1.

    PubMed

    Ditting, Tilmann; Freisinger, Wolfgang; Rodionova, Kristina; Schatz, Johannes; Lale, Nena; Heinlein, Sonja; Linz, Peter; Ott, Christian; Schmieder, Roland E; Scrogin, Karie E; Veelken, Roland

    2016-03-01

    Recently, we showed that renal afferent neurons exhibit a unique firing pattern, i.e., predominantly sustained firing, upon stimulation. Pathological conditions such as renal inflammation likely alter excitability of renal afferent neurons. Here, we tested whether the proinflammatory chemokine CXCL1 alters the firing pattern of renal afferent neurons. Rat dorsal root ganglion neurons (Th11-L2), retrogradely labeled with dicarbocyanine dye, were incubated with CXCL1 (20 h) or vehicle before patch-clamp recording. The firing pattern of neurons was characterized as tonic, i.e., sustained action potential (AP) firing, or phasic, i.e., <5 APs following current injection. Of the labeled renal afferents treated with vehicle, 58.9% exhibited a tonic firing pattern vs. 7.8%, in unlabeled, nonrenal neurons (P < 0.05). However, after exposure to CXCL1, significantly more phasic neurons were found among labeled renal neurons; hence the occurrence of tonic neurons with sustained firing upon electrical stimulation decreased (35.6 vs. 58.9%, P < 0.05). The firing frequency among tonic neurons was not statistically different between control and CXCL1-treated neurons. However, the lower firing frequency of phasic neurons was even further decreased with CXCL1 exposure [control: 1 AP/600 ms (1-2) vs. CXCL1: 1 AP/600 ms (1-1); P < 0.05; median (25th-75th percentile)]. Hence, CXCL1 shifted the firing pattern of renal afferents from a predominantly tonic to a more phasic firing pattern, suggesting that CXCL1 reduced the sensitivity of renal afferent units upon stimulation.

  3. GAD67-GFP+ Neurons in the Nucleus of Roller. II. Subthreshold and Firing Resonance Properties

    PubMed Central

    Berger, A. J.

    2011-01-01

    In the companion paper we show that GAD67-GFP+ (GFP+) inhibitory neurons located in the Nucleus of Roller of the mouse brain stem can be classified into two main groups (tonic and phasic) based on their firing patterns in responses to injected depolarizing current steps. In this study we examined the responses of GFP+ cells to fluctuating sinusoidal (“chirp”) current stimuli. Membrane impedance profiles in response to chirp stimulation showed that nearly all phasic cells exhibited subthreshold resonance, whereas the majority of tonic GFP+ cells were nonresonant. In general, subthreshold resonance was associated with a relatively fast passive membrane time constant and low input resistance. In response to suprathreshold chirp current stimulation at a holding potential just below spike threshold the majority of tonic GFP+ cells fired multiple action potentials per cycle at low input frequencies (<5 Hz) and either stopped firing or were not entrained by the chirp at higher input frequencies (= tonic low-pass cells). A smaller group of phasic GFP+ cells did not fire at low input frequency but were able to phase-lock 1:1 at intermediate chirp frequencies (= band-pass cells). Spike timing reliability was tested with repeated chirp stimuli and our results show that phasic cells were able to reliably fire when they phase-locked 1:1 over a relatively broad range of input frequencies. Most tonic low-pass cells showed low reliability and poor phase-locking ability. Computer modeling suggested that these different firing resonance properties among GFP+ cells are due to differences in passive and active membrane properties and spiking mechanisms. This heterogeneity of resonance properties might serve to selectively activate subgroups of interneurons. PMID:21047931

  4. Deep brain stimulation of the globus pallidus internus in the parkinsonian primate: local entrainment and suppression of low-frequency oscillations.

    PubMed

    McCairn, Kevin W; Turner, Robert S

    2009-04-01

    Competing theories seek to account for the therapeutic effects of high-frequency deep brain stimulation (DBS) of the internal globus pallidus (GPi) for medically intractable Parkinson's disease. To investigate this question, we studied the spontaneous activity of 102 pallidal neurons during GPiDBS in two macaques rendered parkinsonian by administration of MPTP. Stimulation through macroelectrodes in the GPi (> or =200 microA at 150 Hz for 30 s) reduced rigidity in one animal and increased spontaneous movement in both. Novel artifact subtraction methods allowed uninterrupted single-unit recording during stimulation. GPiDBS induced phasic (78% of cells) or sustained (22%) peristimulus changes in firing in both pallidal segments. A subset of cells responded at short latency (<2 ms) in a manner consistent with antidromic driving. Later phasic increases clustered at 3- to 5-ms latency. Stimulation-induced decreases were either phasic, clustered at 1-3 ms, or sustained, showing no peristimulus modulation. Response latency and magnitude often evolved over 30 s of stimulation, but responses were relatively stable by the end of that time. GPiDBS reduced mean firing rates modestly and only in GPi (-6.9 spikes/s). Surprisingly, GPiDBS had no net effect on the prevalence or structure of burst firing. GPiDBS did reduce the prevalence of synchronized low-frequency oscillations. Some cell pairs became synchronized instead at the frequency of stimulation. Suppression of low-frequency oscillations did not require high-frequency synchronization, however, or even the presence of a significant peristimulus response. In summary, the therapeutic effects of GPiDBS may be mediated by an abolition of low-frequency synchronized oscillations as a result of phasic driving. PMID:19164104

  5. Dopamine reward prediction-error signalling: a two-component response.

    PubMed

    Schultz, Wolfram

    2016-03-01

    Environmental stimuli and objects, including rewards, are often processed sequentially in the brain. Recent work suggests that the phasic dopamine reward prediction-error response follows a similar sequential pattern. An initial brief, unselective and highly sensitive increase in activity unspecifically detects a wide range of environmental stimuli, then quickly evolves into the main response component, which reflects subjective reward value and utility. This temporal evolution allows the dopamine reward prediction-error signal to optimally combine speed and accuracy. PMID:26865020

  6. Praziquantel: physiological evidence for its site(s) of action in magnesium-paralysed Schistosoma mansoni.

    PubMed

    Blair, K L; Bennett, J L; Pax, R A

    1992-02-01

    The mechanism whereby praziquantel produces a contraction and subsequent flaccid paralysis (a loss of sensitivity to subsequent stimuli) of Schistosoma mansoni in a medium containing an elevated Mg2+:Ca2+ ratio was investigated. In RPMI, praziquantel produced a concentration-dependent tonic contraction of the parasite with an EC50 of 200 nM. Magnesium inhibited the contraction in such a manner as to convert the tonic contraction to a phasic one without altering the peak force generated. The Mg(2+)-dependent block was non-competitive with praziquantel but was competitive with extracellular Ca2+, ratios of 7.5:1;Mg2+:Ca2+ being needed to inhibit the tonic contraction and to induce flaccid paralysis. Flaccid paralysis was associated with a reduced ability of the parasite to take up 45Ca2+ from the bath compared to parasites that had not entered into flaccid paralysis and flaccid paralysis was reversible. Recovery from flaccid paralysis was accelerated by treatments that are expected to increase Ca2+ uptake by the parasite. At a concentration of 500 nM, praziquantel produced 2 distinct phasic contractions in intact parasites incubated in an elevated [Mg2+] medium but only 1 phasic contraction in parasites lacking their surface tegumental membranes. In zero Ca2+ I-RPMI, 10 microM praziquantel produced a phasic contraction of intact parasites but did not stimulate contraction of detegumented parasites until Ca2+ was reintroduced into the bath. These results indicate that praziquantel interacts with specific Ca(2+)-permeable sites in the tegumental and sarcoplasmic membranes of the parasite and that under these conditions of elevated Mg2+:Ca2+ ratios, these sites become blocked by Mg2+, leading to flaccid paralysis of the parasite. PMID:1614741

  7. Coordination of respiratory cycles with wingbeat cycles in the black-billed magpie (Pica pica)

    PubMed

    Boggs; Seveyka; Kilgore; Dial

    1997-01-01

    Magpies fly with a variable pattern of wingstroke, including high-amplitude rapid flaps and low-amplitude slower flaps with interspersed brief glides. This allowed us to test the hypothesis that if phasic coordination between respiratory and wingbeat cycles is important mechanically and energetically, then, as a bird changes its wingbeat cycle, its respiratory cycle should change with it. We also tested the strength of the drive to coordinate respiratory to locomotor cycles by stimulating breathing with 5 % CO2 during flight. We found that magpies (N=5) do shorten their breath cycle time when they shorten their wingbeat cycle time and prolong their breath cycle time when they glide. When the coordination ratio of wingbeat cycles to breaths is 3:1, the pattern of phasic coordination ensures two upstrokes per inspiration and two downstrokes per expiration. Upstroke tends to coincide with the transition into inspiration or with early inspiration and late inspiration. Downstroke tends to coincide with the transition into expiration or with early expiration and late expiration. When magpies switch from a 3:1 ratio to a 2:1 ratio of wingbeat cycles to breaths, they shorten inspiratory time to ensure that upstroke occurs through most of inspiration and downstroke corresponds to the transition into expiration. These phasic coordination patterns ensure that the compression of the airsacs during downstroke can provide a net assistance to expiration and that the expansion of the airsacs with upstroke can provide a net assistance to inspiration. The failure of an atmosphere containing 5 % CO2 to disrupt these phasic coordination patterns between respiratory and locomotory cycles suggests that there may be a potent mechanical and energetic benefit to such coordination.

  8. Interfacial area and two-phase flow structure development measured by a double-sensor probe

    SciTech Connect

    Leung, Waihung; Revankar, S.T.; Ishii, Yoshihiko; Ishii, Mamoru.

    1992-06-01

    In this report, we studied the local phasic characters of dispersed flow regime both at the entrance and at the fully developed regions. Since the dispersed phase is distributed randomly in the medium and enclosed in relatively small interfaces, the phasic measurement becomes difficult to obtain. Local probe must be made with a miniaturized sensor in order to reduce the interface distortion. The double-sensor resistivity probe has been widely used in local void fraction and interface velocity measurements because the are small in comparison with the interfaces. It has been tested and proved to be an accurate local phasic measurement tool. In these experiments, a double-sensor probe was employed to measure the local void fraction and interface velocity in an air-water system. The test section was flow regime can be determined by visualization. Furthermore, local phasic measurements can be verified by photographic studies. We concentrated our study on the bubbly flow regime only. The local measurements were conducted at two axial locations, L/D = 8 and 60, in which the first measurement represents the entrance region where the flow develops, and the second measurement represents the fully developed flow region where the radial profile does not change as the flow moves along the axial direction. Four liquid flow rates were chosen in combination with four different gas injection rates. The superficial liquid velocities were j{sub t} = 1.0, 0.6,0.4, and 0.1 m/s and superficial gas velocities were j{sub g} = 0.0965, 0.0696, 0.0384, and 0.0192 m/s. These combinations put the two-phase flow well in the bubbly flow regime. In this sequence of phenomenological studies, the local void fraction, interface area concentration, sauter mean diameter, bubble velocity and bubble frequency were measured.

  9. Long-term facilitation of genioglossus activity is present in normal humans during NREM sleep

    PubMed Central

    Chowdhuri, Susmita; Pierchala, Lisa; Aboubakr, Salah E.; Shkoukani, Mahdi; Badr, M. Safwan

    2008-01-01

    Episodic hypoxia (EH) is followed by increased ventilatory motor output in the recovery period indicative of long-term facilitation (LTF). We hypothesized that episodic hypoxia evokes LTF of genioglossus (GG) muscle activity in humans during non-rapid eye movement sleep (NREM) sleep. We studied 12 normal non-flow limited humans during stable NREM sleep. We induced 10 brief (3 minute) episodes of isocapnic hypoxia followed by 5 minutes of room air. Measurements were obtained during control, hypoxia, and at 5, 10, 20, 30 and 40 minutes of recovery, respectively, for minute ventilation (V̇I), supraglottic pressure (PSG), upper airway resistance (RUA) and phasic GG electromyogram (EMGGG). In addition, sham studies were conducted on room air. During hypoxia there was a significant increase in phasic EMGGG (202.7±24.1% of control, p<0.01) and in V̇I (123.0±3.3% of control, p<0.05); however, only phasic EMGGG demonstrated a significant persistent increase throughout recovery (198.9±30.9%, 203.6±29.9% and 205.4±26.4% of control, at 5, 10, and 20 minutes of recovery, respectively, p<0.01). In multivariate regression analysis, age and phasic EMGGG activity during hypoxia were significant predictors of EMGGG at recovery 20 minutes. No significant changes in any of the measured parameters were noted during sham studies. Conclusion: 1) EH elicits LTF of GG in normal non-flow limited humans during NREM sleep, without ventilatory or mechanical LTF. 2) GG activity during the recovery period correlates with the magnitude of GG activation during hypoxia, and inversely with age. PMID:17945544

  10. Stress and CRF gate neural activation of BDNF in the mesolimbic reward pathway.

    PubMed

    Walsh, Jessica J; Friedman, Allyson K; Sun, Haosheng; Heller, Elizabeth A; Ku, Stacy M; Juarez, Barbara; Burnham, Veronica L; Mazei-Robison, Michelle S; Ferguson, Deveroux; Golden, Sam A; Koo, Ja Wook; Chaudhury, Dipesh; Christoffel, Daniel J; Pomeranz, Lisa; Friedman, Jeffrey M; Russo, Scott J; Nestler, Eric J; Han, Ming-Hu

    2014-01-01

    Mechanisms controlling release of brain-derived neurotrophic factor (BDNF) in the mesolimbic dopamine reward pathway remain unknown. We report that phasic optogenetic activation of this pathway increases BDNF amounts in the nucleus accumbens (NAc) of socially stressed mice but not of stress-naive mice. This stress gating of BDNF signaling is mediated by corticotrophin-releasing factor (CRF) acting in the NAc. These results unravel a stress context-detecting function of the brain's mesolimbic circuit.

  11. Predicting multidimensional annular flow with a locally based two-fluid model

    SciTech Connect

    Antal, S.P.; Edwards, D.P.; Strayer, T.D.

    1998-06-01

    The purpose of this work was to: develop a methodology to predict annular flows using a multidimensional four-field, two-fluid Computational Fluid Dynamics (CFD) computer code; develop closure models which use the CFD predicted local velocities, phasic volume fractions, etc...; implement a numerical method which allows the discretized equations to have the same characteristics as the differential form; and compare predicted results to local flow field data taken in a R-134a working fluid test section.

  12. Ethanol modulates the VR-1 variant amiloride-insensitive salt taste receptor. I. Effect on TRC volume and Na+ flux.

    PubMed

    Lyall, Vijay; Heck, Gerard L; Phan, Tam-Hao T; Mummalaneni, Shobha; Malik, Shahbaz A; Vinnikova, Anna K; DeSimone, John A

    2005-06-01

    The effect of ethanol on the amiloride- and benzamil (Bz)-insensitive salt taste receptor was investigated by the measurement of intracellular Na(+) activity ([Na(+)](i)) in polarized rat fungiform taste receptor cells (TRCs) using fluorescence imaging and by chorda tympani (CT) taste nerve recordings. CT responses were monitored during lingual stimulation with ethanol solutions containing NaCl or KCl. CT responses were recorded in the presence of Bz (a specific blocker of the epithelial Na(+) channel [ENaC]) or the vanilloid receptor-1 (VR-1) antagonists capsazepine or SB-366791, which also block the Bz-insensitive salt taste receptor, a VR-1 variant. CT responses were recorded at 23 degrees C or 42 degrees C (a temperature at which the VR-1 variant salt taste receptor activity is maximally enhanced). In the absence of permeable cations, ethanol induced a transient decrease in TRC volume, and stimulating the tongue with ethanol solutions without added salt elicited only transient phasic CT responses that were insensitive to elevated temperature or SB-366791. Preshrinking TRCs in vivo with hypertonic mannitol (0.5 M) attenuated the magnitude of the phasic CT response, indicating that in the absence of mineral salts, transient phasic CT responses are related to the ethanol-induced osmotic shrinkage of TRCs. In the presence of mineral salts, ethanol increased the Bz-insensitive apical cation flux in TRCs without a change in cell volume, increased transepithelial electrical resistance across the tongue, and elicited CT responses that were similar to salt responses, consisting of both a transient phasic component and a sustained tonic component. Ethanol increased the Bz-insensitive NaCl CT response. This effect was further enhanced by elevating the temperature from 23 degrees C to 42 degrees C, and was blocked by SB-366791. We conclude that in the presence of mineral salts, ethanol modulates the Bz-insensitive VR-1 variant salt taste receptor. PMID:15928403

  13. Repetition Priming and Cortical Arousal in Healthy Aging and Alzheimer’s Disease

    PubMed Central

    Kane, Amy E.; Festa, Elena K.; Salmon, David P.; Heindel, William C.

    2015-01-01

    Repetition priming refers to a form of implicit memory in which prior exposure to a stimulus facilitates the subsequent processing of the same or a related stimulus. One frequently used repetition priming task is word-stem completion priming. In this task, participants complete a series of beginning word stems with the first word that comes to mind after having viewed, in an unrelated context, words that can complete some of the stems. Patients with Alzheimer’s disease (AD) exhibit a significant deficit in word-stem completion priming, but the neural mechanisms underlying this deficit have yet to be identified. The present study examined the possibility that the word-stem completion priming deficit in AD is due to disruption of ascending neuromodulatory systems that mediate cortical arousal by comparing word-stem completion priming and behavioral measures of spatial orienting and phasic alerting. Results showed that in healthy elderly controls higher levels of phasic alerting were associated with a sharpening of the temporal dynamics of priming across two delay intervals: those with higher levels of alerting showed more immediate priming but less delayed priming than those with lesser levels of alerting. In patients with AD, priming was impaired despite intact levels of phasic alerting and spatial orienting, and group status rather than individual levels of alerting or orienting predicted the magnitude of their stem-completion priming. Furthermore, the change in priming across delays they displayed was not related to level of alerting or orienting. These findings support the role of the noradrenergic projection system in modulating the level of steady-state cortical activation (or “cortical tonus”) underlying both phasic alerting and the temporal dynamics of repetition priming. However, impaired priming in patients with AD does not appear to be due to disruption of this neuromodulatory system. PMID:25701794

  14. GAD67-GFP+ neurons in the Nucleus of Roller: a possible source of inhibitory input to hypoglossal motoneurons. I. Morphology and firing properties.

    PubMed

    van Brederode, J F M; Yanagawa, Y; Berger, A J

    2011-01-01

    In this study we examined the electrophysiological and morphological properties of inhibitory neurons located just ventrolateral to the hypoglossal motor (XII) nucleus in the Nucleus of Roller (NR). In vitro experiments were performed on medullary slices derived from postnatal day 5 (P5) to P15 GAD67-GFP knock-in mouse pups. on cell recordings from GFP+ cells in NR in rhythmic slices revealed that these neurons are spontaneously active, although their spiking activity does not exhibit inspiratory phase modulation. Morphologically, GFP+ cells were bi- or multipolar cells with small- to medium-sized cell bodies and small dendritic trees that were often oriented parallel to the border of the XII nucleus. GFP+ cells were classified as either tonic or phasic based on their firing responses to depolarizing step current stimulation in whole cell current clamp. Tonic GFP+ cells fired a regular train of action potentials (APs) throughout the duration of the pulse and often showed rebound spikes after a hyperpolarizing step. In contrast, phasic GFP+ neurons did not fire throughout the depolarizing current step but instead fired fewer than four APs at the onset of the pulse or fired multiple APs, but only after a marked delay. Phasic cells had a significantly smaller input resistance and shorter membrane time constant than tonic GFP+ cells. In addition, phasic GFP+ cells differed from tonic cells in the shape and time course of their spike afterpotentials, the minimum firing frequency at threshold current amplitude, and the slope of their current-frequency relationship. These results suggest that GABAergic neurons in the NR are morphologically and electrophysiologically heterogeneous cells that could provide tonic inhibitory synaptic input to HMs. PMID:21047932

  15. Quantitative differences among EMG activities of muscles innervated by subpopulations of hypoglossal and upper spinal motoneurons during non-REM sleep - REM sleep transitions: a window on neural processes in the sleeping brain.

    PubMed

    Rukhadze, I; Kamani, H; Kubin, L

    2011-12-01

    In the rat, a species widely used to study the neural mechanisms of sleep and motor control, lingual electromyographic activity (EMG) is minimal during non-rapid eye movement (non-REM) sleep and then phasic twitches gradually increase after the onset of REM sleep. To better characterize the central neural processes underlying this pattern, we quantified EMG of muscles innervated by distinct subpopulations of hypoglossal motoneurons and nuchal (N) EMG during transitions from non-REM sleep to REM sleep. In 8 chronically instrumented rats, we recorded cortical EEG, EMG at sites near the base of the tongue where genioglossal and intrinsic muscle fibers predominate (GG-I), EMG of the geniohyoid (GH) muscle, and N EMG. Sleep-wake states were identified and EMGs quantified relative to their mean levels in wakefulness in successive 10 s epochs. During non-REM sleep, the average EMG levels differed among the three muscles, with the order being N>GH>GG-I. During REM sleep, due to different magnitudes of phasic twitches, the order was reversed to GG-I>GH>N. GG-I and GH exhibited a gradual increase of twitching that peaked at 70-120 s after the onset of REM sleep and then declined if the REM sleep episode lasted longer. We propose that a common phasic excitatory generator impinges on motoneuron pools that innervate different muscles, but twitching magnitudes are different due to different levels of tonic motoneuronal hyperpolarization. We also propose that REM sleep episodes of average durations are terminated by intense activity of the central generator of phasic events, whereas long REM sleep episodes end as a result of a gradual waning of the tonic disfacilitatory and inhibitory processes.

  16. Theta and gamma coordination of hippocampal networks during waking and rapid eye movement sleep.

    PubMed

    Montgomery, Sean M; Sirota, Anton; Buzsáki, György

    2008-06-25

    Rapid eye movement (REM) sleep has been considered a paradoxical state because, despite the high behavioral threshold to arousing perturbations, gross physiological patterns in the forebrain resemble those of waking states. To understand how intrahippocampal networks interact during REM sleep, we used 96 site silicon probes to record from different hippocampal subregions and compared the patterns of activity during waking exploration and REM sleep. Dentate/CA3 theta and gamma synchrony was significantly higher during REM sleep compared with active waking. In contrast, gamma power in CA1 and CA3-CA1 gamma coherence showed significant decreases in REM sleep. Changes in unit firing rhythmicity and unit-field coherence specified the local generation of these patterns. Although these patterns of hippocampal network coordination characterized the more common tonic periods of REM sleep (approximately 95% of total REM), we also detected large phasic bursts of local field potential power in the dentate molecular layer that were accompanied by transient increases in the firing of dentate and CA1 neurons. In contrast to tonic REM periods, phasic REM epochs were characterized by higher theta and gamma synchrony among the dentate, CA3, and CA1 regions. These data suggest enhanced dentate processing, but limited CA3-CA1 coordination during tonic REM sleep. In contrast, phasic bursts of activity during REM sleep may provide windows of opportunity to synchronize the hippocampal trisynaptic loop and increase output to cortical targets. We hypothesize that tonic REM sleep may support off-line mnemonic processing, whereas phasic bursts of activity during REM may promote memory consolidation.

  17. [Preliminary results of studies of the cardiovascular system in members of the 2d expedition in the Mir orbital station].

    PubMed

    Egorov, A D; Baevskiĭ, R M; Itsekhovskiĭ, O G; Fedorov, B M; Turchanova, V F

    1988-01-01

    Three crewmembers of the second expedition onboard Mir were examined. Their physiological data (bioelectric activity of the heart, phasic structure of the cardiac cycle, circulation parameters at rest and circulation responses to exercise ergometry tests and LBNP tests) were monitored and transmitted to the Earth. This paper presents the physiological data obtained, their interpretation and conclusion that the Commander during his longest-term flight remained in best shape. Individual responses of each cosmonaut in terms of adaptation to flight conditions are discussed.

  18. Brain Regions Engaged by Part- and Whole-task Performance in a Video Game: A Model-based Test of the Decomposition Hypothesis

    PubMed Central

    Anderson, John R.; Bothell, Daniel; Fincham, Jon M.; Anderson, Abraham R.; Poole, Ben; Qin, Yulin

    2013-01-01

    Part- and whole-task conditions were created by manipulating the presence of certain components of the Space Fortress video game. A cognitive model was created for two-part games that could be combined into a model that performed the whole game. The model generated predictions both for behavioral patterns and activation patterns in various brain regions. The activation predictions concerned both tonic activation that was constant in these regions during performance of the game and phasic activation that occurred when there was resource competition. The model’s predictions were confirmed about how tonic and phasic activation in different regions would vary with condition. These results support the Decomposition Hypothesis that the execution of a complex task can be decomposed into a set of information-processing components and that these components combine unchanged in different task conditions. In addition, individual differences in learning gains were predicted by individual differences in phasic activation in those regions that displayed highest tonic activity. This individual difference pattern suggests that the rate of learning of a complex skill is determined by capacity limits. PMID:21557648

  19. Nd3+-substituted (Zr1-xCex)O2 (0.0 ≤ x ≤ 1.0) system: Synthesis, structural and thermophysical investigations

    NASA Astrophysics Data System (ADS)

    Nandi, Chiranjit; Grover, V.; Sahu, M.; Krishnan, K.; Guleria, A.; Kaity, Santu; Prakash, Amrit; Tyagi, A. K.

    2016-10-01

    In order to mimic co-loading of Pu and Am in zirconia, Nd0.20[Zr1-xCex]0.80O1.90 (0.0 ≤ x ≤ 1.0) system was synthesized and thoroughly characterized by X-ray diffraction (XRD) and Raman spectroscopy. The entire system was found to be single-phasic fluorite-type and most interesting result is stabilization of multi-phasic ceria-zirconia system in a single-phasic system by substituting Nd3+. Raman spectroscopy revealed entirely different nature of defects prevalent in the solid solutions possessing F-type structure across the composition range. The heat capacity of representative compositions was measured by heat flux-type differential scanning calorimeter. Specific heat capacity of the solid solutions was found to increase with decreasing CeO2 content. Different thermodynamic functions such as enthalpy increment, entropy and Gibbs energy functions were determined using heat capacity values. The lattice thermal expansion (298-1273 K) behaviour of the few selected compositions revealed a gradual increase in thermal expansion coefficient with increasing CeO2 content.

  20. Respiratory-related activity of cricothyroid muscle in awake normal humans.

    PubMed

    Wheatley, J R; Brancatisano, A; Engel, L A

    1991-05-01

    The role of the cricothyroid muscle (CT) in respiration is unclear. To examine the respiratory-related electrical activity of the CT, we measured its electromyogram (EMG) and compared it with that of the alae nasi (AN) in eight healthy subjects. During quiet breathing the CT EMG phasing was inspiratory in seven subjects. This pattern was similar to the AN with respect to phasing and shape of the integrated EMG. The onset of phasic CT and AN activity related to inspiration preceded flow by 173 +/- 39 and 570 +/- 76 (SE) ms, respectively (P less than 0.01). We measured the duration from onset of phasic activity to peak of the EMG (TA) and the total cycle duration (TT). TA/TT of the CT was 0.29 +/- 0.02, similar to that of the AN (0.28 +/- 0.03). Inspiratory resistive loading, panting, and voluntary hyperventilation increased CT activity above the peak level seen during tidal breathing. Voluntary glottic closure increased CT activity to a level above tonic but below peak tidal activity. The findings suggest that the phasic electrical activity of the CT simulates predominantly that of an upper airway dilator. PMID:1864803

  1. Rapid eye movement sleep behavior disorder and rapid eye movement sleep without atonia in narcolepsy.

    PubMed

    Dauvilliers, Yves; Jennum, Poul; Plazzi, Giuseppe

    2013-08-01

    Narcolepsy is a rare disabling hypersomnia disorder that may include cataplexy, sleep paralysis, hypnagogic hallucinations, and sleep-onset rapid eye movement (REM) periods, but also disrupted nighttime sleep by nocturnal awakenings, and REM sleep behavior disorder (RBD). RBD is characterized by dream-enacting behavior and impaired motor inhibition during REM sleep (REM sleep without atonia, RSWA). RBD is commonly associated with neurodegenerative disorders including Parkinsonisms, but is also reported in narcolepsy in up to 60% of patients. RBD in patients with narcolepsy is, however, a distinct phenotype with respect to other RBD patients and characterized also by absence of gender predominance, elementary rather than complex movements, less violent behavior and earlier age at onset of motor events, and strong association to narcolepsy with cataplexy/hypocretin deficiency. Patients with narcolepsy often present dissociated sleep features including RSWA, increased density of phasic chin EMG and frequent shift from REM to NREM sleep, with or without associated clinical RBD. Most patients with narcolepsy with cataplexy lack the hypocretin neurons in the lateral hypothalamus. Tonic and phasic motor activities in REM sleep and dream-enacting behavior are mostly reported in presence of cataplexy. Narcolepsy without cataplexy is a condition rarely associated with hypocretin deficiency. We proposed that hypocretin neurons are centrally involved in motor control during wakefulness and sleep in humans, and that hypocretin deficiency causes a functional defect in the motor control involved in the development of cataplexy during wakefulness and RBD/RSWA/phasic motor activity during REM sleep.

  2. Distinct roles for GABA across multiple timescales in mammalian circadian timekeeping

    PubMed Central

    DeWoskin, Daniel; Myung, Jihwan; Belle, Mino D. C.; Piggins, Hugh D.; Takumi, Toru; Forger, Daniel B.

    2015-01-01

    The suprachiasmatic nuclei (SCN), the central circadian pacemakers in mammals, comprise a multiscale neuronal system that times daily events. We use recent advances in graphics processing unit computing to generate a multiscale model for the SCN that resolves cellular electrical activity down to the timescale of individual action potentials and the intracellular molecular events that generate circadian rhythms. We use the model to study the role of the neurotransmitter GABA in synchronizing circadian rhythms among individual SCN neurons, a topic of much debate in the circadian community. The model predicts that GABA signaling has two components: phasic (fast) and tonic (slow). Phasic GABA postsynaptic currents are released after action potentials, and can both increase or decrease firing rate, depending on their timing in the interspike interval, a modeling hypothesis we experimentally validate; this allows flexibility in the timing of circadian output signals. Phasic GABA, however, does not significantly affect molecular timekeeping. The tonic GABA signal is released when cells become very excited and depolarized; it changes the excitability of neurons in the network, can shift molecular rhythms, and affects SCN synchrony. We measure which neurons are excited or inhibited by GABA across the day and find GABA-excited neurons are synchronized by—and GABA-inhibited neurons repelled from—this tonic GABA signal, which modulates the synchrony in the SCN provided by other signaling molecules. Our mathematical model also provides an important tool for circadian research, and a model computational system for the many multiscale projects currently studying brain function. PMID:26130805

  3. Coding Properties of Three Intrinsically Distinct Retinal Ganglion Cells under Periodic Stimuli: A Computational Study

    PubMed Central

    Wang, Lei; Qiu, Yi-Hong; Zeng, Yanjun

    2016-01-01

    As the sole output neurons in the retina, ganglion cells play significant roles in transforming visual information into spike trains, and then transmitting them to the higher visual centers. However, coding strategies that retinal ganglion cells (RGCs) adopt to accomplish these processes are not completely clear yet. To clarify these issues, we investigate the coding properties of three types of RGCs (repetitive spiking, tonic firing, and phasic firing) by two different measures (spike-rate and spike-latency). Model results show that for periodic stimuli, repetitive spiking RGC and tonic RGC exhibit similar spike-rate patterns. Their spike- rates decrease gradually with increased stimulus frequency, moreover, variation of stimulus amplitude would change the two RGCs' spike-rate patterns. For phasic RGC, it activates strongly at medium levels of frequency when the stimulus amplitude is low. While if high stimulus amplitude is applied, phasic RGC switches to respond strongly at low frequencies. These results suggest that stimulus amplitude is a prominent factor in regulating RGCs in encoding periodic signals. Similar conclusions can be drawn when analyzes spike-latency patterns of the three RGCs. More importantly, the above phenomena can be accurately reproduced by Hodgkin's three classes of neurons, indicating that RGCs can perform the typical three classes of firing dynamics, depending on the distinctions of ion channel densities. Consequently, model results from the three RGCs may be not specific, but can also applicable to neurons in other brain regions which exhibit part(s) or all of the Hodgkin's three excitabilities. PMID:27721751

  4. Single Dose of a Dopamine Agonist Impairs Reinforcement Learning in Humans: Evidence from Event-related Potentials and Computational Modeling of Striatal-Cortical Function

    PubMed Central

    Santesso, Diane L.; Evins, A. Eden; Frank, Michael J.; Cowman Schetter, Erika M.; Bogdan, Ryan; Pizzagalli, Diego A.

    2011-01-01

    Animal findings have highlighted the modulatory role of phasic dopamine (DA) signaling in incentive learning, particularly in the acquisition of reward-related behavior. In humans, these processes remain largely unknown. In a recent study we demonstrated that a single low dose of a D2/D3 agonist (pramipexole) – assumed to activate DA autoreceptors and thus reduce phasic DA bursts – impaired reward learning in healthy subjects performing a probabilistic reward task. The purpose of the present study was to extend these behavioral findings using event-related potentials and computational modeling. Compared to the placebo group, participants receiving pramipexole showed increased feedback-related negativity to probabilistic rewards and decreased activation in dorsal anterior cingulate regions previously implicated in integrating reinforcement history over time. Additionally, findings of blunted reward learning in participants receiving pramipexole were simulated by reduced presynaptic DA signaling in response to reward in a neural network model of striatal-cortical function. These preliminary findings offer important insights on the role of phasic DA signals on reinforcement learning in humans, and provide initial evidence regarding the spatio-temporal dynamics of brain mechanisms underlying these processes. PMID:18726908

  5. Time-dependent expression of hypertonic effects on bullfrog taste nerve responses to salts and bitter substances.

    PubMed

    Mashiyama, Kazunori; Nozawa, Yuhei; Ohtubo, Yoshitaka; Kumazawa, Takashi; Yoshii, Kiyonori

    2014-03-27

    We previously showed that the hypertonicity of taste stimulating solutions modified tonic responses, the quasi-steady state component following the transient (phasic) component of each integrated taste nerve response. Here we show that the hypertonicity opens tight junctions surrounding taste receptor cells in a time-dependent manner and modifies whole taste nerve responses in bullfrogs. We increased the tonicity of stimulating solutions with non-taste substances such as urea or ethylene glycol. The hypertonicity enhanced phasic responses to NaCl>0.2M, and suppressed those to NaCl<0.1M, 1mM CaCl2, and 1mM bitter substances (quinine, denatonium and strychnine). The hypertonicity also enhanced the phasic responses to a variety of 0.5M salts such as LiCl and KCl. The enhancing effect was increased by increasing the difference between the ionic mobilities of the cations and anions in the salt. A preincubation time >20s in the presence of 1M non-taste substances was needed to elicit both the enhancing and suppressing effects. Lucifer Yellow CH, a paracellular marker dye, diffused into bullfrog taste receptor organs in 30s in the presence of hypertonicity. These results agreed with our proposed mechanism of hypertonic effects that considered the diffusion potential across open tight junctions. PMID:24513402

  6. Physiological responses to near-miss outcomes and personal control during simulated gambling.

    PubMed

    Clark, Luke; Crooks, Ben; Clarke, Robert; Aitken, Michael R F; Dunn, Barnaby D

    2012-03-01

    Near-miss outcomes during gambling are non-win outcomes that fall close to a pay-out. While objectively equivalent to an outright miss, near-misses motivate ongoing play and may therefore be implicated in the development of disordered gambling. Given naturalistic data showing increases in heart rate (HR) and electrodermal activity (EDA) during periods of real gambling play, we sought to explore the phasic impact of win, near-miss and full-miss outcomes on physiological arousal in a controlled laboratory environment. EDA and HR were monitored as healthy, student participants (n = 33) played a simulated slot-machine task involving unpredictable monetary wins. A second gambling distortion, perceived personal control, was manipulated within the same task by allowing the participant to select the play icon on some trials, and having the computer automatically select the play icon on other trials. Near-misses were rated as less pleasant than full-misses. However, on trials that involved personal choice, near-misses produced higher ratings of 'continue to play' than full-misses. Winning outcomes were associated with phasic EDA responses that did not vary with personal choice. Compared to full-misses, near-miss outcomes also elicited an EDA increase, which was greater on personal choice trials. Near-misses were also associated with greater HR acceleration than other outcomes. Near-miss outcomes are capable of eliciting phasic changes in physiological arousal consistent with a state of subjective excitement, despite their objective non-win status.

  7. Dopamine D1 receptor blockade impairs alcohol seeking without reducing dorsal striatal activation to cues of alcohol availability

    PubMed Central

    Fanelli, Rebecca R; Robinson, Donita L

    2015-01-01

    Introduction Alcohol-associated cues activate both ventral and dorsal striatum in functional brain imaging studies of heavy drinkers. In rodents, alcohol-associated cues induce changes in neuronal firing frequencies and increase dopamine release in ventral striatum, but the impact of alcohol-associated cues on neuronal activity in dorsal striatum is unclear. We previously reported phasic changes in action potential frequency in the dorsomedial and dorsolateral striatum after cues that signaled alcohol availability, prompting approach behavior. Methods We investigated the hypothesis that dopamine transmission modulates these phasic firing changes. Rats were trained to self-administer alcohol, and neuronal activity was monitored with extracellular electrophysiology during “anticipatory” cues that signaled the start of the operant session. Sessions were preceded by systemic administration of the D1-type dopamine receptor antagonist SCH23390 (0, 10, and 20 μg/kg). Results SCH23390 significantly decreased firing rates during the 60 s prior to cue onset without reducing phasic excitations immediately following the cues. While neuronal activation to cues might be expected to initiate behavioral responses, in this study alcohol seeking was reduced despite the presence of dorsal striatal excitations to alcohol cues. Conclusions These data suggest that D1 receptor antagonism reduces basal firing rates in the dorsal striatum and modulates the ability of neuronal activation to “anticipatory” cues to initiate alcohol seeking in rats with an extensive history of alcohol self-administration. PMID:25642390

  8. Arousal and consumer in-store behavior.

    PubMed

    Groeppel-Klein, Andrea

    2005-11-15

    From a psychophysiological point of view, arousal is a fundamental feature of behavior. As reported in different empirical studies based on insights from theories of consumer behavior, store atmosphere should evoke phasic arousal reactions to attract consumers. Most of these empirical investigations used verbal scales to measure consumers' perceived phasic arousal at the point-of-sale (POS). However, the validity of verbal arousal measurement is questioned; self-reporting methods only allow a time-lagged measurement. Furthermore, the selection of inappropriate items to represent perceived arousal is criticized, and verbal reports require some form of cognitive evaluation of perceived arousal by the individual, who might (in a non-measurement condition) not even be aware of the arousal. By contrast, phasic electrodermal reaction (EDR) has proven to be the most appropriate and valid indicator for measuring arousal [W. Boucsein, Physiologische Grundlagen und Messmethoden der dermalen Aktivität. In: F. Rösler (Ed.), Enzyklopädie der Psychologie, Bereich Psychophysiologie, Band 1: Grundlagen and Methoden der Psychophysiologie, Kapitel, Vol. 7, Hogrefe, Göttingen, 2001, pp. 551-623] that could be relevant to behavior. EDR can be recorded simultaneously to the perception of stimuli. Furthermore, telemetric online device can be used, which enables physiological arousal measurement while participants can move freely through the store and perform the assigned task in the experiments. The present paper delivers insights on arousal theory and results from empirical studies using EDR to measure arousal at the POS. PMID:16216690

  9. Effect of He-Ne laser irradiation on spontaneous contractive activity and basal tone level of rat portal vein

    NASA Astrophysics Data System (ADS)

    Petrishchev, Nikolai N.; Barabanova, Valeria V.; Mikhailova, Irina A.; Chephu, Svetlana G.

    2000-11-01

    To study the effect of He-Ne irradiation (632.8 nm, 15 mW/cm2) on spontaneous contractive activity the fragments of rat portal vein weremounted isometrically in Krebs buffer. Irradiation of vessel fragments by He-Ne laser during 3,5 and 10 min caused the decrease of ton up to 50%, which lasted in postirradiation period (the observation time - 10 min). The frequency of phasic and tonic contractions did not change, but the amplitude increased up to 40% as compared to the initial level. The decreased basal tone level and the increased amplitude of phasic oscillations lasted in postirradiation period. Adding NO synthasa blocator (N - nitro-L-arginine) to Krebs solution before irradiation caused no significant changes mentioned above parameters. Irradiation and coputing of the same parameters of spontaneous contractive activity of vena porta caused no effects, mentioned in the absence of the blocator. From the results it is concluded that the decrease of tone is evoked by the increase of EDRF production and cGMP. The increase of amplitude of phasic and tonic contractions is connected with increase of Ca++ entry in every contraction cycle as a result of membrane Ca++ pool increase.

  10. Time-dependent expression of hypertonic effects on bullfrog taste nerve responses to salts and bitter substances.

    PubMed

    Mashiyama, Kazunori; Nozawa, Yuhei; Ohtubo, Yoshitaka; Kumazawa, Takashi; Yoshii, Kiyonori

    2014-03-27

    We previously showed that the hypertonicity of taste stimulating solutions modified tonic responses, the quasi-steady state component following the transient (phasic) component of each integrated taste nerve response. Here we show that the hypertonicity opens tight junctions surrounding taste receptor cells in a time-dependent manner and modifies whole taste nerve responses in bullfrogs. We increased the tonicity of stimulating solutions with non-taste substances such as urea or ethylene glycol. The hypertonicity enhanced phasic responses to NaCl>0.2M, and suppressed those to NaCl<0.1M, 1mM CaCl2, and 1mM bitter substances (quinine, denatonium and strychnine). The hypertonicity also enhanced the phasic responses to a variety of 0.5M salts such as LiCl and KCl. The enhancing effect was increased by increasing the difference between the ionic mobilities of the cations and anions in the salt. A preincubation time >20s in the presence of 1M non-taste substances was needed to elicit both the enhancing and suppressing effects. Lucifer Yellow CH, a paracellular marker dye, diffused into bullfrog taste receptor organs in 30s in the presence of hypertonicity. These results agreed with our proposed mechanism of hypertonic effects that considered the diffusion potential across open tight junctions.

  11. Orienting of attention, pupil size, and the norepinephrine system.

    PubMed

    Gabay, Shai; Pertzov, Yoni; Henik, Avishai

    2011-01-01

    This research examined a novel suggestion regarding the involvement of the locus coeruleus-norepinephrine (LC-NE) system in orienting reflexive (exogenous) attention. A common procedure for studying exogenous orienting of attention is Posner's cuing task. Importantly, one can manipulate the required level of target processing by changing task requirements, which, in turn, can elicit a different time course of inhibition of return (IOR). An easy task (responding to target location) produces earlier onset IOR, whereas a demanding task (responding to target identity) produces later onset IOR. Aston-Jones and Cohen (Annual Review of Neuroscience, 28, 403-450, 2005) presented a theory suggesting two different modes of LC activity: tonic and phasic. Accordingly, we suggest that in the more demanding task, the LC-NE system is activated in phasic mode, and in the easier task, it is activated in tonic mode. This, in turn, influences the appearance of IOR. We examined this suggestion by measuring participants' pupil size, which has been demonstrated to correlate with the LC-NE system, while they performed cuing tasks. We found a response-locked phasic dilation of the pupil in the discrimination task, as compared with the localization task, which may reflect different firing modes of the LC-NE system during the two tasks. We also demonstrated a correlation between pupil size at the time of cue presentation and magnitude of IOR.

  12. Genetic analysis and marker assisted identification of life phases of red alga Gracilaria corticata (J. Agardh).

    PubMed

    Baghel, Ravi S; Kumari, Puja; Bijo, A J; Gupta, Vishal; Reddy, C R K; Jha, B

    2011-08-01

    The present study firstly reports the cytological and molecular marker assisted differentiation of isomorphic population of Gracilaria corticata (J. Agardh) with inter and intra-phasic genetic diversity analysis using ISSR markers. The genetic diversity of inbreeding population of G. corticata as determined in terms of percentage of polymorphic loci (PPL), average heterozygosity (He) and Shannon's Weaver index (I) were 59.80, 0.59 and 1.21, respectively. The inter-phasic pair-wise average polymorphism were found to be 31.6% between male and female, 24.0% in male and tetrasporophyte and 25.3% in female and tetrasporophyte. The intra-phasic average polymorphisms were calculated as a maximum of 5.5% between females, 4.2% between males and the lowest 2.4% between tetrasporophytes. The primer 10 generated a marker of 800 bp specific to male and 650 bp to female gametophyte, while the primer 17 generated a marker of 2,500 bp specific to tetrasporophyte. Both the UPGMA based dendrogram and PCA analysis clustered all the three life phases differentially as distinct identity. Cytological analysis by chromosome count revealed 24 chromosomes in both haploid male and female gametophytes (N) and 48 for diploid (2 N) tetrasporophyte further confirming their genetic distinctness. The life phase specific markers reported in this study could be of help in breeding programmes where differentiation of life phases at the early developmental stages is crucial.

  13. Dynamic brain mapping of behavior change: tracking response initiation and inhibition to changes in reinforcement rate.

    PubMed

    Schlund, Michael W; Magee, Sandy; Hudgins, Caleb D

    2012-10-01

    Adaptive behavior change is supported by executive control processes distributed throughout a prefrontal-striatal-parietal network. Yet, the temporal dynamics of regions in the network have not been characterized. Using functional magnetic resonance imaging (fMRI), we tracked changes brain activation while subjects initiated and inhibited responding in accordance with changes in reinforcement rate. During imaging, subjects completed a free-operant task that involved repeated transitions between fixed-ratio reinforcement and extinction (RF:EXT), where reinforcement rate decreased and responding was inhibited, and between extinction and fixed-ratio reinforcement (EXT:RF), where reinforcement rate increased and responding was initiated. Our whole-brain temporal assessment revealed that transitions which required initiating and inhibiting responding prompted positive phasic responses in a prefrontal-parietal network, the insula and thalamus. However, response initiation prompted by an increase in reinforcement rate during the EXT:RF transition elicited positive phasic responses in reward-sensitive striatal regions. Furthermore, response inhibition prompted by a decrease in reinforcement rate during the RF:EXT transition elicited negative phasic responses in ventral frontal regions sensitive to value and contingency. Our findings highlight the temporal dynamics of a brain network that supports behavioral changes (initiation and inhibition) resulting from changes in local reinforcement rates.

  14. Rapid signalling in distinct dopaminergic axons during locomotion and reward.

    PubMed

    Howe, M W; Dombeck, D A

    2016-07-28

    Dopaminergic projection axons from the midbrain to the striatum are crucial for motor control, as their degeneration in Parkinson disease results in profound movement deficits. Paradoxically, most recording methods report rapid phasic dopamine signalling (~100-ms bursts) in response to unpredicted rewards, with little evidence for movement-related signalling. The leading model posits that phasic signalling in striatum-targeting dopamine neurons drives reward-based learning, whereas slow variations in firing (tens of seconds to minutes) in these same neurons bias animals towards or away from movement. However, current methods have provided little evidence to support or refute this model. Here, using new optical recording methods, we report the discovery of rapid phasic signalling in striatum-targeting dopaminergic axons that is associated with, and capable of triggering, locomotion in mice. Axons expressing these signals were largely distinct from those that responded to unexpected rewards. These results suggest that dopaminergic neuromodulation can differentially impact motor control and reward learning with sub-second precision, and indicate that both precise signal timing and neuronal subtype are important parameters to consider in the treatment of dopamine-related disorders. PMID:27398617

  15. Rapid signalling in distinct dopaminergic axons during locomotion and reward.

    PubMed

    Howe, M W; Dombeck, D A

    2016-07-28

    Dopaminergic projection axons from the midbrain to the striatum are crucial for motor control, as their degeneration in Parkinson disease results in profound movement deficits. Paradoxically, most recording methods report rapid phasic dopamine signalling (~100-ms bursts) in response to unpredicted rewards, with little evidence for movement-related signalling. The leading model posits that phasic signalling in striatum-targeting dopamine neurons drives reward-based learning, whereas slow variations in firing (tens of seconds to minutes) in these same neurons bias animals towards or away from movement. However, current methods have provided little evidence to support or refute this model. Here, using new optical recording methods, we report the discovery of rapid phasic signalling in striatum-targeting dopaminergic axons that is associated with, and capable of triggering, locomotion in mice. Axons expressing these signals were largely distinct from those that responded to unexpected rewards. These results suggest that dopaminergic neuromodulation can differentially impact motor control and reward learning with sub-second precision, and indicate that both precise signal timing and neuronal subtype are important parameters to consider in the treatment of dopamine-related disorders.

  16. Rapid eye movement sleep behavior disorder and rapid eye movement sleep without atonia in narcolepsy.

    PubMed

    Dauvilliers, Yves; Jennum, Poul; Plazzi, Giuseppe

    2013-08-01

    Narcolepsy is a rare disabling hypersomnia disorder that may include cataplexy, sleep paralysis, hypnagogic hallucinations, and sleep-onset rapid eye movement (REM) periods, but also disrupted nighttime sleep by nocturnal awakenings, and REM sleep behavior disorder (RBD). RBD is characterized by dream-enacting behavior and impaired motor inhibition during REM sleep (REM sleep without atonia, RSWA). RBD is commonly associated with neurodegenerative disorders including Parkinsonisms, but is also reported in narcolepsy in up to 60% of patients. RBD in patients with narcolepsy is, however, a distinct phenotype with respect to other RBD patients and characterized also by absence of gender predominance, elementary rather than complex movements, less violent behavior and earlier age at onset of motor events, and strong association to narcolepsy with cataplexy/hypocretin deficiency. Patients with narcolepsy often present dissociated sleep features including RSWA, increased density of phasic chin EMG and frequent shift from REM to NREM sleep, with or without associated clinical RBD. Most patients with narcolepsy with cataplexy lack the hypocretin neurons in the lateral hypothalamus. Tonic and phasic motor activities in REM sleep and dream-enacting behavior are mostly reported in presence of cataplexy. Narcolepsy without cataplexy is a condition rarely associated with hypocretin deficiency. We proposed that hypocretin neurons are centrally involved in motor control during wakefulness and sleep in humans, and that hypocretin deficiency causes a functional defect in the motor control involved in the development of cataplexy during wakefulness and RBD/RSWA/phasic motor activity during REM sleep. PMID:23219054

  17. Brain regions engaged by part- and whole-task performance in a video game: a model-based test of the decomposition hypothesis.

    PubMed

    Anderson, John R; Bothell, Daniel; Fincham, Jon M; Anderson, Abraham R; Poole, Ben; Qin, Yulin

    2011-12-01

    Part- and whole-task conditions were created by manipulating the presence of certain components of the Space Fortress video game. A cognitive model was created for two-part games that could be combined into a model that performed the whole game. The model generated predictions both for behavioral patterns and activation patterns in various brain regions. The activation predictions concerned both tonic activation that was constant in these regions during performance of the game and phasic activation that occurred when there was resource competition. The model's predictions were confirmed about how tonic and phasic activation in different regions would vary with condition. These results support the Decomposition Hypothesis that the execution of a complex task can be decomposed into a set of information-processing components and that these components combine unchanged in different task conditions. In addition, individual differences in learning gains were predicted by individual differences in phasic activation in those regions that displayed highest tonic activity. This individual difference pattern suggests that the rate of learning of a complex skill is determined by capacity limits.

  18. Role of Cysteine Residues in the Carboxyl-Terminus of the Follicle-Stimulating Hormone Receptor in Intracellular Traffic and Postendocytic Processing.

    PubMed

    Melo-Nava, Brenda; Casas-González, Patricia; Pérez-Solís, Marco A; Castillo-Badillo, Jean; Maravillas-Montero, José L; Jardón-Valadez, Eduardo; Zariñán, Teresa; Aguilar-Rojas, Arturo; Gallay, Nathalie; Reiter, Eric; Ulloa-Aguirre, Alfredo

    2016-01-01

    Posttranslational modifications occurring during the biosynthesis of G protein-coupled receptors include glycosylation and palmitoylation at conserved cysteine residues located in the carboxyl-terminus of the receptor. In a number of these receptors, these modifications play an important role in receptor function and particularly, in intracellular trafficking. In the present study, the three cysteine residues present in the carboxyl-terminus of the human FSHR were replaced with glycine by site-directed mutagenesis. Wild-type and mutant (Cys627/629/655Gly) FSHRs were then transiently expressed in HEK-293 cells and analyzed for cell-surface plasma membrane expression, agonist-stimulated signaling and internalization, and postendocytic processing in the absence and presence of lysosome and/or proteasome inhibitors. Compared with the wild-type FSHR, the triple mutant FSHR exhibited ~70% reduction in plasma membrane expression as well as a profound attenuation in agonist-stimulated cAMP production and ERK1/2 phosphorylation. Incubation of HEK-293 cells expressing the wild-type FSHR with 2-bromopalmitate (palmitoylation inhibitor) for 6 h, decreased plasma membrane expression of the receptor by ~30%. The internalization kinetics and β-arrestin 1 and 2 recruitment were similar between the wild-type and triple mutant FSHR as disclosed by assays performed in non-equilibrium binding conditions and by confocal microscopy. Cells expressing the mutant FSHR recycled the internalized FSHR back to the plasma membrane less efficiently than those expressing the wild-type FSHR, an effect that was counteracted by proteasome but not by lysosome inhibition. These results indicate that replacement of the cysteine residues present in the carboxyl-terminus of the FSHR, impairs receptor trafficking from the endoplasmic reticulum/Golgi apparatus to the plasma membrane and its recycling from endosomes back to the cell surface following agonist-induced internalization. Since in the FSHR these

  19. Interactions of the alpha2A-adrenoceptor with multiple Gi-family G-proteins: studies with pertussis toxin-resistant G-protein mutants.

    PubMed Central

    Wise, A; Watson-Koken, M A; Rees, S; Lee, M; Milligan, G

    1997-01-01

    The alpha2A-adrenoceptor is the prototypic example of the family of G-protein-coupled receptors which function by activation of 'Gi-like' pertussis toxin-sensitive G-proteins. A number of members of this subfamily of G-proteins are often co-expressed in a single cell type. To examine the interaction of this receptor with individual Gi-family G-proteins the porcine alpha2A-adrenoceptor was transiently transfected into COS-7 cells either alone or with each of wild-type Gi1alpha, Gi2alpha and Gi3alpha or mutations of each of these G-proteins in which the cysteine residue which is the target for pertussis toxin-catalysed ADP-ribosylation was exchanged for a glycine residue. The alpha2-adrenoceptor agonist UK14304 stimulated both high-affinity GTPase activity and the binding of guanosine 5'-[gamma-35thio]-triphosphate (GTP[35S]), when expressed without any additional G-protein. These effects were greatly reduced by pretreatment of the cells with pertussis toxin. Co-expression of each of the wild-type Gi-like G-protein alpha-subunits resulted in enhanced agonist activation of the cellular G-protein population which was fully prevented by pretreatment with pertussis toxin. Co-expression of the receptor along with the cysteine-to-glycine mutations of Gi1alpha, Gi2alpha and Gi3alpha resulted in agonist stimulation of these G-proteins, which was as great as that of the wild type proteins, but now the agonist stimulation produced over that due to the activation of endogenously expressed Gi-like G-proteins was resistant to pertussis toxin treatment. The Cys --> Gly mutations of Gi1alpha, Gi2alpha and Gi3alpha were each also able to limit agonist-mediated stimulation of adenylate cyclase activity. The degree of agonist-mediated activation of the pertussis toxin-resistant mutant of Gi1alpha was correlated highly both with the level of expression of this G-protein and with the level of expression of the alpha2A-adrenoceptor. Half-maximal stimulation of high-affinity GTPase

  20. Rare coding variants of the adenosine A3 receptor are increased in autism: on the trail of the serotonin transporter regulome

    PubMed Central

    2013-01-01

    Background Rare genetic variation is an important class of autism spectrum disorder (ASD) risk factors and can implicate biological networks for investigation. Altered serotonin (5-HT) signaling has been implicated in ASD, and we and others have discovered multiple, rare, ASD-associated variants in the 5-HT transporter (SERT) gene leading to elevated 5-HT re-uptake and perturbed regulation. We hypothesized that loci encoding SERT regulators harbor variants that impact SERT function and/or regulation and therefore could contribute to ASD risk. The adenosine A3 receptor (A3AR) regulates SERT via protein kinase G (PKG) and other signaling pathways leading to enhanced SERT surface expression and catalytic activity. Methods To test our hypothesis, we asked whether rare variants in the A3AR gene (ADORA3) were increased in ASD cases vs. controls. Discovery sequencing in a case-control sample and subsequent analysis of comparison exome sequence data were conducted. We evaluated the functional impact of two variants from the discovery sample on A3AR signaling and SERT activity. Results Sequencing discovery showed an increase of rare coding variants in cases vs. controls (P=0.013). While comparison exome sequence data did not show a significant enrichment (P=0.071), combined analysis strengthened evidence for association (P=0.0025). Two variants discovered in ASD cases (Leu90Val and Val171Ile) lie in or near the ligand-binding pocket, and Leu90Val was enriched individually in cases (P=0.040). In vitro analysis of cells expressing Val90-A3AR revealed elevated basal cGMP levels compared with the wildtype receptor. Additionally, a specific A3AR agonist increased cGMP levels across the full time course studied in Val90-A3AR cells, compared to wildtype receptor. In Val90-A3AR/SERT co-transfections, agonist stimulation elevated SERT activity over the wildtype receptor with delayed 5-HT uptake activity recovery. In contrast, Ile171-A3AR was unable to support agonist stimulation of

  1. Functional activity of the cannabinoid 1 receptor is not affected by opioid antagonists in the rat brain

    PubMed Central

    2013-01-01

    Background WIN55212-2 is a synthetic cannabinoid agonist and selective to cannabinoid 1 (CB1) receptors, which are distributed mainly in the central nervous system. Opioid receptors and CB1 receptors have several similarities in terms of their intracellular signal transduction mechanisms, distributions, and pharmacological action. Several studies have therefore sought to describe the functional interactions between opioids and cannabinoids at the cellular and behavioral levels. The present study investigated agonist-stimulated [35S]GTPγS binding by WIN55212-2 in rat brain membranes and determined the antagonism by selective opioid antagonists at the level of receptor-ligand interaction and intracellular signal transduction. Methods Sprague-Dawley rats (male, n = 20) were euthanized for the preparation of brain membranes. In agonist-stimulated [35S]GTPγS binding by WIN55212-2, the values of EC50 and maximum stimulation (% over basal) were determined in the absence or presence of the µ, κ and δ opioid receptor antagonists naloxone (20 nM), norbinaltorphimine (3 nM), and naltrindole (3 nM), respectively. Ke values for opioid antagonist inhibition in the absence or presence of each opioid receptor antagonist were calculated using the following equation: [nanomolar antagonist] / (dose ratio of EC50 - 1). Results In WIN55212-2-stimulated [35S]GTPγS binding in the rat brain membranes, the values of EC50 and maximum stimulation (% over basal) were 154 ± 39.5 nM and 27.6 ± 5.3% over basal, respectively. Addition of selective opioid antagonists did not produce a significant rightward shift in the WIN55212-2 concentration-response curve, and Ke values were not applicable. Conclusions Our results suggest that the functional activity of WIN55212-2-stimulated [35S]GTPγS binding was not affected by opioid antagonists in the rat brain membranes. Although the exact mechanism remains unclear, our results may partially elucidate their actions. PMID:23560193

  2. Role of Cysteine Residues in the Carboxyl-Terminus of the Follicle-Stimulating Hormone Receptor in Intracellular Traffic and Postendocytic Processing

    PubMed Central

    Melo-Nava, Brenda; Casas-González, Patricia; Pérez-Solís, Marco A.; Castillo-Badillo, Jean; Maravillas-Montero, José L.; Jardón-Valadez, Eduardo; Zariñán, Teresa; Aguilar-Rojas, Arturo; Gallay, Nathalie; Reiter, Eric; Ulloa-Aguirre, Alfredo

    2016-01-01

    Posttranslational modifications occurring during the biosynthesis of G protein-coupled receptors include glycosylation and palmitoylation at conserved cysteine residues located in the carboxyl-terminus of the receptor. In a number of these receptors, these modifications play an important role in receptor function and particularly, in intracellular trafficking. In the present study, the three cysteine residues present in the carboxyl-terminus of the human FSHR were replaced with glycine by site-directed mutagenesis. Wild-type and mutant (Cys627/629/655Gly) FSHRs were then transiently expressed in HEK-293 cells and analyzed for cell-surface plasma membrane expression, agonist-stimulated signaling and internalization, and postendocytic processing in the absence and presence of lysosome and/or proteasome inhibitors. Compared with the wild-type FSHR, the triple mutant FSHR exhibited ~70% reduction in plasma membrane expression as well as a profound attenuation in agonist-stimulated cAMP production and ERK1/2 phosphorylation. Incubation of HEK-293 cells expressing the wild-type FSHR with 2-bromopalmitate (palmitoylation inhibitor) for 6 h, decreased plasma membrane expression of the receptor by ~30%. The internalization kinetics and β-arrestin 1 and 2 recruitment were similar between the wild-type and triple mutant FSHR as disclosed by assays performed in non-equilibrium binding conditions and by confocal microscopy. Cells expressing the mutant FSHR recycled the internalized FSHR back to the plasma membrane less efficiently than those expressing the wild-type FSHR, an effect that was counteracted by proteasome but not by lysosome inhibition. These results indicate that replacement of the cysteine residues present in the carboxyl-terminus of the FSHR, impairs receptor trafficking from the endoplasmic reticulum/Golgi apparatus to the plasma membrane and its recycling from endosomes back to the cell surface following agonist-induced internalization. Since in the FSHR these

  3. Central HIV-1 Tat exposure elevates anxiety and fear conditioned responses of male mice concurrent with altered mu-opioid receptor-mediated G-protein activation and β-arrestin 2 activity in the forebrain.

    PubMed

    Hahn, Yun K; Paris, Jason J; Lichtman, Aron H; Hauser, Kurt F; Sim-Selley, Laura J; Selley, Dana E; Knapp, Pamela E

    2016-08-01

    Co-exposure to opiates and HIV/HIV proteins results in enhanced CNS morphological and behavioral deficits in HIV(+) individuals and in animal models. Opiates with abuse liability, such as heroin and morphine, bind preferentially to and have pharmacological actions through μ-opioid-receptors (MORs). The mechanisms underlying opiate-HIV interactions are not understood. Exposure to the HIV-1 transactivator of transcription (Tat) protein causes neurodegenerative outcomes that parallel many aspects of the human disease. We have also observed that in vivo exposure to Tat results in apparent changes in morphine efficacy, and thus have hypothesized that HIV proteins might alter MOR activation. To test our hypothesis, MOR-mediated G-protein activation was determined in neuroAIDS-relevant forebrain regions of transgenic mice with inducible CNS expression of HIV-1 Tat. G-protein activation was assessed by MOR agonist-stimulated [(35)S]guanosine-5'-O-(3-thio)triphosphate ([(35)S]GTPγS) autoradiography in brain sections, and in concentration-effect curves of MOR agonist-stimulated [(35)S]GTPγS binding in membranes isolated from specific brain regions. Comparative studies were done using the MOR-selective agonist DAMGO ([D-Ala(2), N-MePhe(4), Gly-ol]-enkephalin) and a more clinically relevant agonist, morphine. Tat exposure reduced MOR-mediated G-protein activation in an agonist, time, and regionally dependent manner. Levels of the GPCR regulatory protein β-arrestin-2, which is involved in MOR desensitization, were found to be elevated in only one affected brain region, the amygdala; amygdalar β-arrestin-2 also showed a significantly increased association with MOR by co-immunoprecipitation, suggesting decreased availability of MOR. Interestingly, this correlated with changes in anxiety and fear-conditioned extinction, behaviors that have substantial amygdalar input. We propose that HIV-1 Tat alters the intrinsic capacity of MOR to signal in response to agonist binding

  4. Activated AMPK inhibits PPAR-{alpha} and PPAR-{gamma} transcriptional activity in hepatoma cells.

    PubMed

    Sozio, Margaret S; Lu, Changyue; Zeng, Yan; Liangpunsakul, Suthat; Crabb, David W

    2011-10-01

    AMP-activated protein kinase (AMPK) and peroxisome proliferator-activated receptor-α (PPAR-α) are critical regulators of short-term and long-term fatty acid oxidation, respectively. We examined whether the activities of these molecules were coordinately regulated. H4IIEC3 cells were transfected with PPAR-α and PPAR-γ expression plasmids and a peroxisome-proliferator-response element (PPRE) luciferase reporter plasmid. The cells were treated with PPAR agonists (WY-14,643 and rosiglitazone), AMPK activators 5-aminoimidazole-4-carboxamide riboside (AICAR) and metformin, and the AMPK inhibitor compound C. Both AICAR and metformin decreased basal and WY-14,643-stimulated PPAR-α activity; compound C increased agonist-stimulated reporter activity and partially reversed the effect of the AMPK activators. Similar effects on PPAR-γ were seen, with both AICAR and metformin inhibiting PPRE reporter activity. Compound C increased basal PPAR-γ activity and rosiglitazone-stimulated activity. In contrast, retinoic acid receptor-α (RAR-α), another nuclear receptor that dimerizes with retinoid X receptor (RXR), was largely unaffected by the AMPK activators. Compound C modestly increased AM580 (an RAR agonist)-stimulated activity. The AMPK activators did not affect PPAR-α binding to DNA, and there was no consistent correlation between effects of the AMPK activators and inhibitor on PPAR and the nuclear localization of AMPK-α subunits. Expression of either a constitutively active or dominant negative AMPK-α inhibited basal and WY-14,643-stimulated PPAR-α activity and basal and rosiglitazone-stimulated PPAR-γ activity. We concluded that the AMPK activators AICAR and metformin inhibited transcriptional activities of PPAR-α and PPAR-γ, whereas inhibition of AMPK with compound C activated both PPARs. The effects of AMPK do not appear to be mediated through effects on RXR or on PPAR/RXR binding to DNA. These effects are independent of kinase activity and instead appear to

  5. Opioid-receptor (OR) signaling cascades in rat cerebral cortex and model cell lines: the role of plasma membrane structure.

    PubMed

    Ujčíková, H; Brejchová, J; Vošahlíková, M; Kagan, D; Dlouhá, K; Sýkora, J; Merta, L; Drastichová, Z; Novotný, J; Ostašov, P; Roubalová, L; Parenti, M; Hof, M; Svoboda, P

    2014-01-01

    Large number of extracellular signals is received by plasma membrane receptors which, upon activation, transduce information into the target cell interior via trimeric G-proteins (GPCRs) and induce activation or inhibition of adenylyl cyclase enzyme activity (AC). Receptors for opioid drugs such as morphine (micro-OR, delta-OR and kappa-OR) belong to rhodopsin family of GPCRs. Our recent results indicated a specific up-regulation of AC I (8-fold) and AC II (2.5-fold) in plasma membranes (PM) isolated from rat brain cortex exposed to increasing doses of morphine (10-50 mg/kg) for 10 days. Increase of ACI and ACII represented the specific effect as the amount of ACIII-ACIX, prototypical PM marker Na, K-ATPase and trimeric G-protein alpha and beta subunits was unchanged. The up-regulation of ACI and ACII faded away after 20 days since the last dose of morphine. Proteomic analysis of these PM indicated that the brain cortex of morphine-treated animals cannot be regarded as being adapted to this drug because significant up-regulation of proteins functionally related to oxidative stress and alteration of brain energy metabolism occurred. The number of delta-OR was increased 2-fold and their sensitivity to monovalent cations was altered. Characterization of delta-OR-G-protein coupling in model HEK293 cell line indicated high ability of lithium to support affinity of delta-OR response to agonist stimulation. Our studies of PM structure and function in context with desensitization of GPCRs action were extended by data indicating participation of cholesterol-enriched membrane domains in agonist-specific internalization of delta-OR. In HEK293 cells stably expressing delta-OR-G(i)1alpha fusion protein, depletion of PM cholesterol was associated with the decrease in affinity of G-protein response to agonist stimulation, whereas maximum response was unchanged. Hydrophobic interior of isolated PM became more "fluid", chaotically organized and accessible to water molecules

  6. Short-Term Potentiation in the Control of Pharyngeal Muscles in Obstructive Apnea Patients

    PubMed Central

    Younes, Magdy; Loewen, Andrea; Ostrowski, Michele; Hanly, Patrick

    2014-01-01

    Study Objectives: To determine if activation of the genioglossus (GG) muscle during obstructive apnea events involves short-term potentiation (STP) and is followed by sustained activation beyond the obstructive phase (after-discharge). Design: Physiological study. Setting: Sleep laboratory in a tertiary hospital. Participants: Twenty-one patients with obstructive apnea. Interventions: Polysomnography on continuous positive airway pressure (CPAP) with measurement of genioglossus activity. Brief dial-downs of CPAP to induce obstructive events. Measurements and Results: Peak, phasic, and tonic genioglossus activities were measured breath-by-breath before, during, and following three-breath obstructions. Tonic but not phasic activity increased immediately following the first obstructed breath (4.9 ± 1.6 versus 3.6 ± 1.2 %GGMAX; P = 0.01) under conditions where stimuli to genioglossus activation were likely constant, strongly implicating STP in mediating recruitment of tonic activity. Both phasic and tonic activities declined slowly after relief of obstruction (after-discharge). Decay time constants were systematically shorter for phasic than for tonic activity (7.5 ± 3.8 versus 18.1 ± 8.4 sec; P < 0.001). Decay time-constant of peak activity correlated with tonic, but not phasic, recruitment. Cortical arousal near the end of obstruction resulted in a lower after-discharge (P < 0.01). Contribution of tonic activity to the increase in peak activity (6–65%Peak), as well as the decay constant (6–30 sec), varied considerably among patients. Conclusions: Short-term potentiation contributes to recruitment of the genioglossus during obstructive episodes and results in sustained tonic activity beyond the obstructive phase, thereby potentially preventing recurrence of obstruction. Wide response differences among subjects suggest that this mechanism may contribute to severity of the disorder. The after-discharge is inhibited following cortical arousal, potentially

  7. Abnormal temporal difference reward-learning signals in major depression.

    PubMed

    Kumar, P; Waiter, G; Ahearn, T; Milders, M; Reid, I; Steele, J D

    2008-08-01

    Anhedonia is a core symptom of major depressive disorder (MDD), long thought to be associated with reduced dopaminergic function. However, most antidepressants do not act directly on the dopamine system and all antidepressants have a delayed full therapeutic effect. Recently, it has been proposed that antidepressants fail to alter dopamine function in antidepressant unresponsive MDD. There is compelling evidence that dopamine neurons code a specific phasic (short duration) reward-learning signal, described by temporal difference (TD) theory. There is no current evidence for other neurons coding a TD reward-learning signal, although such evidence may be found in time. The neuronal substrates of the TD signal were not explored in this study. Phasic signals are believed to have quite different properties to tonic (long duration) signals. No studies have investigated phasic reward-learning signals in MDD. Therefore, adults with MDD receiving long-term antidepressant medication, and comparison controls both unmedicated and acutely medicated with the antidepressant citalopram, were scanned using fMRI during a reward-learning task. Three hypotheses were tested: first, patients with MDD have blunted TD reward-learning signals; second, controls given an antidepressant acutely have blunted TD reward-learning signals; third, the extent of alteration in TD signals in major depression correlates with illness severity ratings. The results supported the hypotheses. Patients with MDD had significantly reduced reward-learning signals in many non-brainstem regions: ventral striatum (VS), rostral and dorsal anterior cingulate, retrosplenial cortex (RC), midbrain and hippocampus. However, the TD signal was increased in the brainstem of patients. As predicted, acute antidepressant administration to controls was associated with a blunted TD signal, and the brainstem TD signal was not increased by acute citalopram administration. In a number of regions, the magnitude of the abnormal

  8. Effect of KC399, a newly synthesized K+ channel opener, on acetylcholine-induced electrical and mechanical activities in rabbit tracheal smooth muscle.

    PubMed

    Kamei, K; Nabata, H; Kuriyama, H; Watanabe, Y; Itoh, T

    1995-08-01

    1. Effects of KC399, an opener of ATP-sensitive K+ channels were investigated on membrane potential, isometric force and intracellular Ca2+ ([Ca2+]i) mobilization induced by acetylcholine (ACh) in smooth muscle from the rabbit trachea. 2. In these smooth muscle cells, ACh (0.1 and 1 microM) depolarized the membrane in a concentration-dependent manner, KC399 (1-100 nM) hyperpolarized the membrane whether in the presence or absence of ACh. When the concentration of ACh was increased, the absolute values of the membrane potential induced by the maximum concentration of KC399 were less negative. 3. ACh (0.1 to 10 microM) concentration-dependently produced a phasic, followed by a tonic increase in both [Ca2+]i and force. KC399 (above 3 nM) lowered the resting [Ca2+]i and attenuated the ACh-induced phasic and tonic increases in [Ca2+]i and force, in a concentration-dependent manner. The magnitude of the inhibition was greater for the ACh-induced tonic responses than for the phasic ones. Nicardipine (0.3 microM), a blocker of the L-type Ca2+ channel, attenuated the ACh-induced tonic, but not phasic, increases in [Ca2+]i and force. KC399 further attenuated the ACh-induced tonic responses in the presence of nicardipine. 4. In beta-escin-skinned strips, Ca2+ (0.3-10 microM) produced a contraction in a concentration-dependent manner. KC399 (0.1 microM) had no effect on the Ca(2+)-force relationship in the presence or absence of ATP with GTP. However, at a very high concentration (1 microM), this agent slightly shifted the relationship to the right and attenuated the maximum Ca(2+)-induced contraction. 5. We conclude that, in rabbit tracheal smooth muscle, the membrane hyperpolarization induced byKC399 attenuates the ACh-induced tonic increase in [Ca2+], through an inhibition of nicardipinesensitive and -insensitive Ca2+-influxes, thus causing an inhibition of the ACh-induced tonic contraction. The ACh-induced phasic increase in [Ca2+]i and force are also inhibited, but less

  9. [Caffeine-induced contraction of guinea pig taenia coli (author's transl)].