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Sample records for agonist-stimulated phasic myometrial

  1. Innate immune responses to microbial agonist stimulations in heterophils and monocytes from young commercial turkeys

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The innate immune system recognizes microbial pathogens and pathogen associated molecular patterns and incites inflammatory immune responses to control the infection. Here, we examined functional innate immune responses of turkey heterophils and monocytes to microbial agonist stimulations by measur...

  2. MECHANISMS UNDERLYING ALC13 INHIBITION OF AGONIST-STIMULATED INOSITOL PHOSPHATE ACCUMULATION

    EPA Science Inventory

    Possible mechanisms of AlC13-induced inhibition of agonist-stimulated inositol phosphate (IP) accumulation were investigated using rat brain cortex slices, synaptosomes or homogenates. nder conditions in which AlC13 inhibits carbachol (CARB) stimulated IP accumulation (Gp-mediate...

  3. 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

  4. The androgen receptor mediates antiapoptotic function in myometrial cells.

    PubMed

    Li, H; Li, Y; Morin, D; Plymate, S; Lye, S; Dong, X

    2014-01-01

    During pregnancy, myometrial phenotype is programmed into three characteristic stages referred to as the early proliferative, the midterm hypertrophic, and the late contractile stage. Increased myometrial growth in the early and midterm of pregnancy involves a complex process of cell proliferation, antiapoptosis and differentiation. We have previously demonstrated that the androgen receptor (AR) is required for myometrial cell proliferation by modulating IGF-1 signaling during early pregnancy. Here, we report that AR also exerts its antiapoptotic function in human myometrial cells. Enhanced AR expression protects, whereas AR silencing sensitizes myometrial cells to both intrinsic and extrinsic apoptotic stimuli. AR agonist inhibits, whereas AR antagonist induces myometrial cells to undergo apoptotic cell death. Gene microarray analysis confirms that the central functions of AR in myometrial cells are to regulate cell cycling and apoptosis through three major gene groups involving the epidermal growth factor (EGF) signaling, RNA splicing and DNA repair processes. AR mediates its antiapoptotic function through two distinct pathways. In the receptor-dependent pathway, AR is required for the expression of several protein factors within the EGF signaling pathway. Through the PI3K/Akt pathway, AR enhances the expression of the antiapoptotic protein Mcl-1. In the ligand-dependent pathway, AR agonist triggers the activation of Src kinase, which in turn phosphorylates STAT3 to increase Mcl-1 expression. We conclude from these results that the AR signaling exerts antiapoptotic function in myometrial cells, further supporting its key role in programming of myometrial phenotype. PMID:25032861

  5. 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

  6. Estrogen maintains myometrial tumors in a lymphangioleiomyomatosis model.

    PubMed

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

    2016-04-01

    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

  7. RNA editing of the human serotonin 5-HT(2C) receptor delays agonist-stimulated calcium release.

    PubMed

    Price, R D; Sanders-Bush, E

    2000-10-01

    RNA encoding the human 5-HT(2C) receptor undergoes adenosine-to-inosine RNA editing events at five positions in the putative second intracellular loop, with a corresponding reduction in receptor/G-protein coupling. Agonist-stimulated calcium release was examined in NIH-3T3 fibroblasts stably expressing the nonedited human INI (hINI) or the edited hVSV or hVGV variants. We hypothesized that different receptor isoforms would show altered dynamics of agonist-induced calcium release. The three isoforms showed a rightward shift in agonist concentration-response curves for eliciting calcium release (EC(50) values: hINI, 2.2 nM; hVSV, 15 nM; hVGV, 49 nM). Additionally, the hVGV receptor showed a blunted and delayed [Ca(2+)](i) peak compared with the hINI or hVSV receptor isoforms. These distinctions in agonist-induced [Ca(2+)](i) release imply that edited 5-HT(2C) receptors may produce distinct physiological responses within the central nervous system. PMID:10999958

  8. TLR8 agonists stimulate newly recruited monocyte-derived cells into potent APCs that enhance HBsAg immunogenicity

    PubMed Central

    Du, Jun; Wu, Zhiyuan; Ren, Shurong; Wei, Yong; Gao, Meihua; Randolph, Gwendalyn J.; Qu, Chunfeng

    2011-01-01

    We previously reported that synthetic or natural Toll-like receptor (TLR) 7/8 agonists present within dead cells enhanced cell-associated antigen presentation both in vitro and in vivo. Here, we investigated the immunopotency of different chemically synthesized TLR7/8 agonists, Resiquimod, Gardiquimod, CL075, and CL097, on HBsAg immunogenicity. These agonists stimulated inflammatory monocyte-derived cells to become potent antigen-presenting dendritic cells (DCs), which augmented HBsAg specific T cell proliferation after they were conditioned with HBsAg. The TLR8 agonist CL075 and the TLR7/8 dual agonist CL097 showed more potent effects than the TLR7 agonist. Compared with alum adjuvant, when HBsAg mixed with CL075 was injected intramuscularly into mice, more monocyte-derived DCs carried antigens into draining lymph nodes and spleens. Specific Abs, particularly IgG2a, were significantly increased, and more IL-5 and IFN-γ were produced by splenocytes and intrahepatic immunocytes in mice that received HBsAg mixed with CL075 and CL097. These results suggest that TLR8 agonists are good candidates to enhance recombinant HBsAg immunogenicity to induce specific humoral and cellular immune responses. PMID:20637759

  9. mTOR Complexes Repress Hypertrophic Agonist-Stimulated Expression of Connective Tissue Growth Factor in Adult Cardiac Muscle Cells.

    PubMed

    Sundararaj, Kamala; Pleasant, Dorea L; Moschella, Phillip C; Panneerselvam, Kavin; Balasubramanian, Sundaravadivel; Kuppuswamy, Dhandapani

    2016-02-01

    Connective tissue growth factor (CTGF) is a fibrogenic cytokine that promotes fibrosis in various organs. In the heart, both cardiomyocytes (CM) and cardiac fibroblasts have been reported as a source of CTGF expression, aiding cardiac fibrosis. Although the mammalian target of rapamycin (mTOR) forms 2 distinct complexes, mTORC1 and mTORC2, and plays a central role in integrating biochemical signals for protein synthesis and cellular homeostasis, we explored its role in CTGF expression in adult feline CM. CM were stimulated with 10 μM phenylephrine (PE), 200 nM angiotensin (Ang), or 100 nM insulin for 24 hours. PE and Ang, but not insulin, caused an increase in CTGF mRNA expression with the highest expression observed with PE. Inhibition of mTOR with torin1 but not rapamycin significantly enhanced PE-stimulated CTGF expression. Furthermore, silencing of raptor and rictor using shRNA adenoviral vectors to suppress mTORC1 and mTORC2, respectively, or blocking phosphatidylinositol 3-kinase (PI3K) signaling with LY294002 (LY) or Akt signaling by dominant-negative Akt expression caused a substantial increase in PE-stimulated CTGF expression as measured by both mRNA and secreted protein levels. However, studies with dominant-negative delta isoform of protein kinase C demonstrate that delta isoform of protein kinase C is required for both agonist-induced CTGF expression and mTORC2/Akt-mediated CTGF suppression. Finally, PE-stimulated CTGF expression was accompanied with a corresponding increase in Smad3 phosphorylation and pretreatment of cells with SIS3, a Smad3 specific inhibitor, partially blocked the PE-stimulated CTGF expression. Therefore, a PI3K/mTOR/Akt axis plays a suppressive role on agonist-stimulated CTGF expression where the loss of this mechanism could be a contributing factor for the onset of cardiac fibrosis in the hypertrophying myocardium. PMID:26371948

  10. Myometrial myxoidosis: a report of 2 cases of a distinctive type of secondary myometrial hypertrophy in patients with lupus erythematosus.

    PubMed

    Veras, Emanuela; Junkins-Hopkins, Jacqueline M; Marinis, Spyridon; Vang, Russell

    2009-03-01

    Myxoid mesenchymal lesions of the uterus are generally restricted to tumors, but non-neoplastic myxoid mesenchymal lesions of the uterus have not received much attention in the literature. We analyzed the clinicopathologic features of 2 patients with lupus erythematosus (ages 43 and 52 yr, respectively) in whom myometrial myxoidosis produced a markedly enlarged uterus with myometrial thickening ("secondary myometrial hypertrophy"). Both patients underwent a hysterectomy for presumed leiomyomas, and intraoperatively an enlarged uterus was noted. On gross examination, the uteri measured 13.5 x 13.5 x 11.5 cm and 14.5 x 11.5 x 9.5 cm, respectively. The significantly thickened myometrium was due to marked expansion of the interstitial compartment of the myometrium, in which non-neoplastic smooth muscle fascicles were widely separated by abundant extracellular mucin producing a striking myxoid appearance ("myxoidosis"). These histologic findings are akin to the pattern of dermal mucin deposition seen in lupus erythematosus. The lesion in each case diffusely involved the entire myometrium. Histochemical stains were performed and showed the following results: mucicarmine-diffusely but weakly positive; periodic acid-schiff (PAS)-negative; colloidal iron-diffuse positive; alcian blue, pH 2.5 (without hyaluronidase digestion)-diffuse positive, and alcian blue, pH 2.5 (with hyaluronidase digestion)-negative. These histochemical findings are consistent with hyaluronic acid. Follow-up in 1 case was not available. In the other case, the patient presented to clinical attention 5 weeks after surgery because of ascites, which after an extensive clinical evaluation was interpreted as being of unknown etiology. To the best of our knowledge, this rare and unusual non-neoplastic myometrial lesion has not been previously described. Pathologists should be aware of its existence because of the distinctive appearance and as it may prompt consideration of various myxoid neoplasms of the

  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. Oxytocin-Stimulated NFAT Transcriptional Activation in Human Myometrial Cells

    PubMed Central

    McArdle, Craig A.; López Bernal, Andrés

    2012-01-01

    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 Ca2+ 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. PMID:22902539

  13. Multiple Signals Regulate PLC beta 3 in Human Myometrial Cells

    PubMed Central

    Zhong, Miao; Murtazina, Dilyara A.; Phillips, Jennifer; Ku, Chun-Ying; Sanborn, Barbara M.

    2008-01-01

    Summary The regulation of PLCB3-Serine1105 phosphorylation by both negative feedback and negative crosstalk facilitates the integration of multiple signaling pathways in myometrial cells. Phospholipase CB3 (PLCB3) Serine1105, a substrate for multiple protein kinases, represents a potential point of convergence of several signaling pathways in the myometrium. To explore this hypothesis, the regulation of PLCB3-Serine1105 phosphorylation (P-S1105) was studied in immortalized and primary human myometrial cells. CPT-cAMP and calcitonin gene-related peptide (CALCA) transiently increased P-S1105. Relaxin also stimulated P-S1105; this effect was partially blocked by the protein kinase A (PRKA) inhibitor Rp-8-CPT-cAMPS. Oxytocin, which stimulates Gαq-mediated pathways, also rapidly increased P-S1105, as did PGF2α and ATP. Oxytocin-stimulated phosphorylation was blocked by the protein kinase C (PRKC) inhibitor Go6976 and by pretreatment overnight with a phorbol ester. Cypermethrin, a PP2B phosphatase inhibitor, but not okadaic acid, a PP1/PP2A inhibitor, prolonged the effect of CALCA on P-S1105, whereas the reverse was the case for the oxytocin-stimulated increase in P-S1105. PLCB3 was the predominant PLC isoform expressed in the myometrial cells and PLCB3 shRNA constructs significantly attenuated oxytocin-stimulated increases in intracellular calcium. Oxytocin-induced phosphatidylinositol (PI) turnover was inhibited by CPT-cAMP and okadaic acid but enhanced by pretreatment with Go6976. CPT-cAMP inhibited oxytocin-stimulated PI turnover in the presence of overexpressed PLCB3, but not overexpressed PLCB3-S1105A. These data demonstrate that both negative crosstalk from the cAMP/PRKA pathway and a negative feedback loop in the oxytocin/G protein/PLCB pathway involving PRKC operate in myometrial cells and suggest that different protein phosphatases predominate in mediating P-S1105 dephosphorylation in these pathways. The integration of multiple signal components at the level

  14. Prolonged agonist stimulation does not alter the protein composition of membrane domains in spite of dramatic changes induced in a specific signaling cascade.

    PubMed

    Matousek, Petr; Novotny, Jirí; Rudajev, Vladimír; Svoboda, Petr

    2005-01-01

    Protein composition of membrane domains prepared by three different procedures (mechanical homogenization, alkaline treatment with 1 M Na2CO3 [pH 11.0], or extraction with nonionic detergent Triton X-100), and isolated from the bulk of plasma membranes by flotation on equilibrium sucrose density gradients, was analyzed by two-dimensional (2D) electrophoresis and compared in preparations from control (quiescent) and agonist-stimulated human embryonic kidney cells (HEK)293 or S49 cells. HEK293 cells (clone e2m11) stably expressing high levels of thyrotropin-releasing hormone receptor and G11alpha protein were stimulated by thyrotropin-releasing hormone and S49 lymphoma cells by the beta-adrenergic receptor agonist isoprenaline. Whereas sustained exposure (16 h) of both cell lines to the appropriate hormones led to substantial cellular redistribution and downregulation of the cognate G proteins (G(q)alpha/G11alpha and G(s)alpha, respectively), the distribution and levels of nonstimulated G(i) proteins remained unchanged. The 2D electrophoretic analysis of membrane domains distinguished approx 150-170 major proteins in these structures and none of these proteins was significantly altered by prolonged agonist stimulation. Furthermore, specific immunochemical determination of a number of plasma membrane markers, including transmembrane and glycosyl-phosphatidylinositol-anchored peripheral proteins, confirmed that their detergent-extractability/solubility was not influenced by hormone treatment. Collectively, our present data indicate that sustained hormone stimulation of target cells does not alter the basic protein composition of membrane domain/raft compartments of the plasma membrane in spite of marked changes proceeding in a given signaling cascade. PMID:15673926

  15. Phasic affective modulation of semantic priming.

    PubMed

    Topolinski, Sascha; Deutsch, Roland

    2013-03-01

    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 facial primes (Experiment 3) in an (in)direct semantic priming paradigm, as well as brief facial feedback in a summative priming paradigm (Experiment 4), yielded increased priming effects under brief positive compared to negative affect. Furthermore, this modulation took place on the level of semantic spreading rather than on strategic mechanisms (Experiment 5). Alternative explanations such as distraction, motivation, arousal, and cognitive tuning could be ruled out. This phasic affective modulation constitutes a mechanism overlooked thus far that may contaminate priming effects in all priming paradigms that involve affective stimuli. Furthermore, this mechanism provides a novel explanation for the observation that priming effects are usually larger for positive than for negative stimuli. Finally, it has important implications for linguistic research, by suggesting that association norms may be biased for affective words. PMID:22732031

  16. Phasic and Sustained Fear are Pharmacologically Dissociable in Rats

    PubMed Central

    Miles, Leigh; Davis, Michael; Walker, David

    2011-01-01

    Previous findings suggest differences in the neuroanatomical substrates of short- (seconds) vs longer-duration (minutes) fear responses. We now report that phasic and sustained fear can also be differentiated pharmacologically, based on their response to several treatments that either are or are not clinically effective anxiolytics. For these experiments, short- or long-duration clicker stimuli were paired with footshock. Acoustic startle amplitude was later measured in the absence of the clicker, or within seconds (phasic fear) or minutes (sustained fear) of its onset. Before testing, rats received a single injection of vehicle, the benzodiazepine chlordiazepoxide, the 5HT1A agonist and dopamine D2 antagonist buspirone, the selective serotonin reuptake inhibitor fluoxetine, or a 3-week treatment with either vehicle or fluoxetine. Chlordiazepoxide blocked sustained, but not phasic startle increases. Acute buspirone, which is not anxiolytic in human beings, did not affect sustained startle increases, but did disrupt phasic increases. Chronic fluoxetine blocked sustained startle increases and unreliably reduced phasic increases; acute fluoxetine affected neither. The results indicate that phasic and sustained fear responses can be pharmacologically dissociated, further validating this distinction, and suggest that sustained startle increases may be especially useful as anxiety models and anxiolytic screens. PMID:21471958

  17. Phasic dopamine release in appetitive behaviors and drug abuse

    PubMed Central

    Wanat, Matthew J.; Willuhn, Ingo; Clark, Jeremy J.; Phillips, Paul E. M.

    2010-01-01

    Short phasic bursts of neuronal activity in dopamine neurons produce rapid and transient increases in extracellular dopamine concentrations throughout the mesocorticolimbic system, which are associated with the initiation of goal-directed behaviors. It is well established that acute exposure to many addictive drugs produce increases in tonic dopamine levels that occur on the order of minutes. However, recent studies suggest that abused drugs similarly enhance phasic dopamine release events that occur on a subsecond time scale. Furthermore, drug experience modulates the synaptic and intrinsic properties of dopamine neurons, which could affect dopamine burst firing and phasic dopamine release. This review will provide a general introduction to the mesolimbic dopamine system, as well as the primary methods used to detect dopamine neurons and dopamine release. We present the role of phasic dopamine release in appetitive behaviors in the context of contemporary theories regarding the function of dopamine. Next we discuss the known drug-induced changes to dopamine neurons and phasic release in both in vitro and in vivo preparations. Finally, we offer a simple model that chronic drug experience attenuates tonic/basal dopamine levels but promotes phasic dopamine release, which may result in aberrant goal-directed behaviors contributing to the development of addiction. PMID:19630749

  18. Kv7 and Kv11 channels in myometrial regulation

    PubMed Central

    Greenwood, Iain A; Tribe, Rachel M

    2014-01-01

    Ion channels play a key role in defining myometrial contractility. Modulation of ion channel populations is proposed to underpin gestational changes in uterine contractility associated with the transition from uterine quiescence to active labour. Of the myriad ion channels present in the uterus, this article will focus upon potassium channels encoded by the KCNQ genes and ether-à-go-go-related (ERG) genes. Voltage-gated potassium channels encoded by KCNQ and ERG (termed Kv7 and Kv11, respectively) are accepted as major determinants of neuronal excitability and the duration of the cardiac action potential. However, there is now growing appreciation that these ion channels have a major functional impact in vascular and non-vascular smooth muscle. Moreover, Kv7 channels may be potential therapeutic targets for the treatment of preterm labour. PMID:24121285

  19. 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.

  20. 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

  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. PMID:25031392

  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. 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. PMID:27060485

  4. 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

  5. Relaxin stimulates myometrial calcium-activated potassium channel activity via protein kinase A.

    PubMed

    Meera, P; Anwer, K; Monga, M; Oberti, C; Stefani, E; Toro, L; Sanborn, B M

    1995-08-01

    Relaxin, a hormone that is elevated during pregnancy, can suppress myometrial contractile activity. Ca(2+)-activated K+ channels (KCa) play a role in the modulation of uterine contractions and myometrial Ca2+ homeostasis and have been implicated in the control of smooth muscle excitability. We now show that relaxin stimulates KCa channels in cell-attached patches in a cell line derived from term pregnant human myometrium. This effect was prevented by the protein kinase A (PKA) antagonist, the Rp diastereomer of adenosine 3',5'-cyclic monophosphothioate (Rp-cAMPS). After patch excision, the channel was activated by PKA and inhibited by alkaline phosphatase. These data suggest that relaxin may promote myometrial quiescence in part by stimulation of KCa channels via a PKA-mediated mechanism. PMID:7653512

  6. CyPPA, a positive modulator of small-conductance Ca(2+)-activated K(+) channels, inhibits phasic uterine contractions and delays preterm birth in mice.

    PubMed

    Skarra, Dana V; Cornwell, Trudy; Solodushko, Viktoriya; Brown, Amber; Taylor, Mark S

    2011-11-01

    Organized uterine contractions, including those necessary for parturition, are dependent on calcium entry through voltage-gated calcium channels in myometrial smooth muscle cells. Recent evidence suggests that small-conductance Ca(2+)-activated potassium channels (K(Ca)2), specifically isoforms K(Ca)2.2 and 2.3, may control these contractions through negative feedback regulation of Ca(2+) entry. We tested whether selective pharmacologic activation of K(Ca)2.2/2.3 channels might depress uterine contractions, providing a new strategy for preterm labor intervention. Western blot analysis and immunofluorescence microscopy revealed expression of both K(Ca)2.2 and K(Ca)2.3 in the myometrium of nonpregnant (NP) and pregnant (gestation day 10 and 16; D10 and D16, respectively) mice. Spontaneous phasic contractions of isolated NP, D10, and D16 uterine strips were all suppressed by the K(Ca)2.2/2.3-selective activator CyPPA in a concentration-dependent manner. This effect was antagonized by the selective K(Ca)2 inhibitor apamin. Whereas CyPPA sensitivity was reduced in D10 and D16 versus NP strips (pIC(50) 5.33 ± 0.09, 4.64 ± 0.03, 4.72 ± 0.10, respectively), all contractions were abolished between 30 and 60 μM. Blunted contractions were associated with CyPPA depression of spontaneous Ca(2+) events in myometrial smooth muscle bundles. Augmentation of uterine contractions with oxytocin or prostaglandin F(2α) did not reduce CyPPA sensitivity or efficacy. Finally, in an RU486-induced preterm labor model, CyPPA significantly delayed time to delivery by 3.4 h and caused a 2.5-fold increase in pup retention. These data indicate that pharmacologic stimulation of myometrial K(Ca)2.2/2.3 channels effectively suppresses Ca(2+)-mediated uterine contractions and delays preterm birth in mice, supporting the potential utility of this approach in tocolytic therapies. PMID:21795518

  7. 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

  8. Intraoperative frozen section diagnosis of depth of myometrial invasion in endometrial adenocarcinoma.

    PubMed

    Fanning, J; Tsukada, Y; Piver, M S

    1990-04-01

    From January 1981 to December 1988, a prospective trial was conducted on 216 consecutive patients undergoing hysterectomy for FIGO stage I endometrial adenocarcinoma to determine the accuracy of intraoperative frozen section (IFS) diagnosis of depth of myometrial invasion. IFS and D&C diagnoses were compared to the permanent section diagnosis to determine their accuracy. Patients with an IFS or D&C diagnosis of grade 3 carcinoma, deep myometrial invasion, cervical invasion, or adnexal involvement were considered high risk for paraaortic nodal metastasis, and paraaortic lymphadenectomy was performed. IFS correctly diagnosed the depth of myometrial invasion in 194 of 204 cases (95%). The sensitivity of IFS diagnosis of deep invasion was 87%, the specificity was 99%, the positive predictive value was 98%, and the negative predictive value was 94%. Grade, subtype, cervical invasion, and adnexal involvement were also accurately diagnosed. Based on IFS and D&C diagnosis, paraaortic lymphadenectomy was performed in 32% of patients, while 68% were considered low risk and were spared paraaortic lymphadenectomy. Eight patients (5%) were incorrectly diagnosed as low risk and did not have paraaortic lymphadenectomy performed. Sixty-five of seventy-three (90%) patients considered high risk on permanent section had paraaortic lymphadenectomies performed on the basis of IFS and D&C diagnosis. Inaccurate IFS diagnosis of depth of myometrial invasion can occur when tumor involves the uterine isthmus or cornua and when tumor invades areas of adenomyosis. PMID:2323612

  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. Relationship between coronary hemodynamic changes and the phasic events of rapid eye movement sleep.

    PubMed

    Dickerson, L W; Huang, A H; Thurnher, M M; Nearing, B D; Verrier, R L

    1993-09-01

    Previous studies in dogs showed dramatic increases in coronary blood flow associated with episodes of sinus tachycardia during rapid eye movement (REM) sleep. The present study demonstrates that 90% of these surges in heart rate and coronary flow are concentrated during periods of phasic REM sleep and only 10% in tonic REM sleep. Intensely phasic REM was distinguished from moderately phasic REM sleep by the degree of phasic eye movement. The surges were three times more frequent during intensely phasic REM than in moderately phasic REM sleep. However, the magnitudes of heart rate (37% +/- 3%) and coronary flow (25% +/- 3%) surges were unaffected by the specific substage of REM sleep. The incidence of surge events was almost eleven times greater in epochs of phasic REM that also contained a muscle twitch than in those that did not. During REM sleep, muscle twitches accompanying surges were not associated with any additional elevations in coronary flow or myocardial demand. Our data indicate that the sinus tachycardia-associated surges in coronary flow represent integrated autonomic responses intrinsic to phasic periods of REM sleep in dogs. PMID:8235240

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

    PubMed

    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

  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. Regulation of human myometrial contractility during pregnancy and labour: are calcium homeostatic pathways important?

    PubMed

    Tribe, R M

    2001-03-01

    If we are to develop new strategies for the treatment and management of preterm and dysfunctional term labour, it is imperative that we improve current understanding of the control of human uterine activity. Despite many studies of animal pregnancy, there is a paucity of knowledge relating to the complex control of human myometrium during pregnancy. It is hypothesized that human myometrium is relatively quiescent during the majority of pregnancy and that as term approaches there is cascade of molecular events that prepare the uterus for labour. This review will consider the cellular mechanisms involved in the regulation of human myometrial activity and the modulation of these by hormonal and mechanical signals. In particular, the contribution of calcium homeostatic pathways to the control of human myometrial contractility during gestation will be discussed. Experimental Physiology (2001) 86.2, 247-254. PMID:11429641

  14. The contribution of Kv7 channels to pregnant mouse and human myometrial contractility.

    PubMed

    McCallum, Laura A; Pierce, Stephanie L; England, Sarah K; Greenwood, Iain A; Tribe, Rachel M

    2011-03-01

    Premature birth accounts for approximately 75% of neonatal mortality and morbidity in the developed world. Despite this, methods for identifying and treating women at risk of preterm labour are limited and many women still present in preterm labour requiring tocolytic therapy to suppress uterine contractility. The aim of this study was to assess the utility of Kv7 channel activators as potential uterine smooth muscle (myometrium) relaxants in tissues from pregnant mice and women. Myometrium was obtained from early and late pregnant mice and from lipopolysaccharide (LPS)-injected mice (day 15 of gestation; model of infection in pregnancy). Human myometrium was obtained at the time of Caesarean section from women at term (38-41 weeks). RT-PCR/qRT-PCR detected KCNQ and KCNE expression in mouse and human myometrium. In mice, there was a global suppression of all KCNQ isoforms, except KCNQ3, in early pregnancy (n= 6, P < 0.001 versus late pregnant); expression subsequently increased in late pregnancy (n= 6). KCNE isoforms were also gestationally regulated (P < 0.05). KCNQ and KCNE isoform expression was slightly down-regulated in myometrium from LPS-treated-mice versus controls (P < 0.05, n= 3-4). XE991 (10 μM, Kv7 inhibitor) significantly increased spontaneous myometrial contractions in vitro in both human and mouse myometrial tissues (P < 0.05) and retigabine/flupirtine (20 μM, Kv7 channel activators) caused profound myometrial relaxation (P < 0.05). In summary, Kv7 activators suppressed myometrial contraction and KCNQ gene expression was sustained throughout gestation, particularly at term. Consequently, activation of the encoded channels represents a novel mechanism for treatment of preterm labour. PMID:20132415

  15. Mares with delayed uterine clearance have an intrinsic defect in myometrial function.

    PubMed

    Rigby, S L; Barhoumi, R; Burghardt, R C; Colleran, P; Thompson, J A; Varner, D D; Blanchard, T L; Brinsko, S P; Taylor, T; Wilkerson, M K; Delp, M D

    2001-09-01

    Persistent, postmating endometritis affects approximately 15% of mares and results in reduced fertility and sizable economic losses to the horse-breeding industry. Mares that are susceptible to postmating endometritis have delayed uterine clearance associated with reduced uterine contractility. Unfortunately, the mechanism for reduced uterine contractility remains an enigma. The present study examined the hypothesis that mares with delayed uterine clearance have an intrinsic contractile defect of the myometrium. Myometrial contractility was evaluated in vitro by measuring isometric tension generated by longitudinal and circular uterine muscle strips in response to KCl, oxytocin, and prostaglandin F(2alpha) (PGF(2alpha)) for young nulliparous mares, older reproductively normal mares, and older mares with delayed uterine clearance. In addition, intracellular Ca(2+) regulation was evaluated using laser cytometry to measure oxytocin-stimulated intracellular Ca(2+) transients of myometrial cells loaded with a Ca(2+)-sensitive fluorescent dye, fluo-4. For all contractile agonists, myometrium from mares with delayed uterine clearance failed to generate as much tension as myometrium from older normal mares. Oxytocin-stimulated intracellular Ca(2+) transients were similar for myometrial cells from mares with delayed uterine clearance and from older normal mares, suggesting that the contractile defect did not result from altered regulation of intracellular Ca(2+) concentration. Furthermore, no apparent age-dependent decline was observed in myometrial contractility; KCl-depolarized and oxytocin-stimulated longitudinal myometrium from young normal mares and older normal mares generated similar responses. However, circular myometrium from young normal mares failed to generate as much tension as myometrium from older normal mares when stimulated with oxytocin or PGF(2alpha), suggesting possible age-related alterations in receptor-second messenger signaling mechanisms downstream

  16. ( 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.

  17. The effect of GnRH on in vitro bovine myometrial activity.

    PubMed

    Giammarino, Angelo; Manera, Maurizio; Robbe, Domenico; Perugini, Monia; Amorena, Michele

    2009-06-01

    The aim of this study was to evaluate, in vitro, the effects of increasing concentrations of GnRH on spontaneous mechanical activity patterns of uterine smooth muscle preparations of cows during the follicular and the luteal phases of the oestrus cycle. Uterine smooth muscle strips from 14 cows in follicular and 9 in luteal phase were collected immediately after slaughter and processed within 60 min from collection. Two strips of the same uterus were mounted in an isolated organ bath with two chambers to evaluate the role of decapeptide GnRH on spontaneous myometrial contractility. After equilibration period at 20 mN resting tension, the mechanical activity of the uterus was recorded for 10 min and the mean contractile force (MCF) was calculated. Then GnRH antagonist (antide) was added to one chamber at fixed concentration (10(-4)mol) and allowed to diffuse in solution and make contact with the strips. Subsequently, GnRH was added to the two baths at the same time at increasing concentration and MCF was recorded for 10 min. The effect of GnRH on spontaneous myometrial activity was evident only in the strips from subjects in follicular phase. Our results are suggestive of the presence of GnRH receptors in bovine myometrial tissue. The involvement of GnRH on uterine contractions at mating can be postulated. PMID:18579322

  18. Mechanical stretch regulates TRPC expression and calcium entry in human myometrial smooth muscle cells.

    PubMed

    Dalrymple, A; Mahn, K; Poston, L; Songu-Mize, E; Tribe, R M

    2007-03-01

    Stretch is known to stimulate myometrial hyperplasia and hypertrophy in early pregnancy and uterine contraction at term. We propose that transduction of the stretch signal involves alteration of intracellular calcium signalling, including changes in transient receptor potential canonical (TRPC) isoform expression. The aim of the present study was to investigate the effect of prolonged mechanical (tonic) stretch in vitro on human myometrial smooth muscle cell calcium signalling and TRPC expression. Cells were cultured from myometrial biopsies, obtained from women undergoing elective Caesarean section at term, grown on Flexiplates and subjected to 25% tonic mechanical stretch for 1, 4 and 14 h. Time-matched control cells were not stretched. Mechanical stretch (14 h) increased basal calcium entry and cyclopiazonic acid (CPA)-induced calcium/Mn(2+) entry (P < 0.05) in Fura-2 loaded cells. The calcium selectivity of CPA-thapsigarin induced inward currents, measured by patch clamp electrophysiology, was also increased in stretched cells compared with control cells (P < 0.05). Real time PCR and Western blot data demonstrated that TRPC3 and TRPC4 mRNA and TRPC3 protein expression were increased by stretch (P < 0.05), respectively. These data support the hypothesis that uterine stretch modulates uterine growth and contractility in pregnancy via alterations in calcium signalling. PMID:17208928

  19. 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

  20. 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.

  1. 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

  2. Phasic study of intestinal homeostasis disruption in experimental intestinal obstruction

    PubMed Central

    Yu, Xiang-Yang; Zou, Chang-Lin; Zhou, Zhen-Li; Shan, Tao; Li, Dong-Hua; Cui, Nai-Qiang

    2014-01-01

    AIM: To investigate the phasic alteration of intestinal homeostasis in an experimental model of intestinal obstruction. METHODS: A rabbit model of intestinal obstruction was established by transforming parts of an infusion set into an in vivo pulled-type locking clamp and creating a uniform controllable loop obstruction in the mesenteric non-avascular zone 8 cm from the distal end of the ileum. The phasic alteration of intestinal homeostasis was studied after intestinal obstruction. The changes in goblet cells, intraepithelial lymphocytes, lamina propria lymphocytes, and intestinal epithelium were quantified from periodic acid-Schiff-stained sections. Ornithine decarboxylase (ODC) activity and serum citrulline levels were measured by high-performance liquid chromatography. Claudin 1 mRNA expression was examined by real-time polymerase chain reaction analysis. Intestinal microorganisms, wet/dry weight ratios, pH values, and endotoxin levels were determined at multiple points after intestinal obstruction. Furthermore, the number and ratio of CD3+, CD4+ and CD8+ T cells were determined by flow cytometry, and secretory IgA levels were measured with an enzyme-linked immunosorbent assay. RESULTS: A suitable controllable rabbit model of intestinal obstruction was established. Intestinal obstruction induced goblet cell damage and reduced cell number. Further indicators of epithelial cell damage were observed as reduced serum citrulline levels and claudin 1 gene expression, and a transient increase in ODC activity. In addition, the wet/dry weight ratio and pH of the intestinal lumen were also dramatically altered. The ratio of Bacillus bifidus and enterobacteria was reversed following intestinal obstruction. The number and area of Peyer’s patches first increased then sharply decreased after the intestinal obstruction, along with an alteration in the ratio of CD4/CD8+ T cells, driven by an increase in CD3+ and CD8+ T cells and a decrease in CD4+ T cells. The number of

  3. Effects of diosgenin on myometrial matrix metalloproteinase-2 and -9 activity and expression in ovariectomized rats.

    PubMed

    Chang, Chi-Chen; Kuan, Tang-Ching; Hsieh, Yao-Yuan; Ho, Ying-Jui; Sun, Yu-Ling; Lin, Chih-Sheng

    2011-01-01

    Diosgenin, a traditional Yam extraction, has been used in hormone replacement for menopausal women. We aimed to investigate the influences of diosgenin administration upon the MMP-2 and -9 activity and expression and reproductive hormones of ovariectomized (OVX) rats, a model of menopausal status. Seven-week old female Wistar rats with bilateral OVX or sham operation (controls) were divided and administered different dosages of diosgenin (0, 10, 50, or 100 mg/kg/day) for 8 weeks. Serum was then sampled for progesterone (P4) and estradiol (E2) assay and uterine horns harvested. Myometrial MMP-2 and -9 activity and expression were surveyed and myometrial collagen expression was also assayed. The results show higher body weight in OVX rats across the 8 weeks post surgery and no significant differences were noted among OVX or Sham rats with diosgenin supplements. There were lower P4 and E2 concentrations in OVX rats compared to Sham rats, and higher P4 concentration of Sham rats post diosgenin supplement. MMP-2 and -9 mRNA expression and activity was lower in OVX rats, although higher MMP-2 and lower MMP-9 activity/mRNA expression was observed in OVX rats post diosgenin supplementation. Collagen mRNA expression was higher in OVX rats compared to Sham controls, and diosgenin administration decreased collagen mRNA expression in OVX rats. In conclusion, diosgenin is associated with gelatinase expression and collagen metabolism in OVX rats. Diosgenin administration can partially reverse the effects of OVX upon MMP functions and hormone status. Adequate diosgenin supplement might modulate myometrial gelatinase expression and collagen metabolism in menopausal subjects. PMID:21814480

  4. Effects of Diosgenin on Myometrial Matrix Metalloproteinase-2 and -9 Activity and Expression in Ovariectomized Rats

    PubMed Central

    Chang, Chi-Chen; Kuan, Tang-Ching; Hsieh, Yao-Yuan; Ho, Ying-Jui; Sun, Yu-Ling; Lin, Chih-Sheng

    2011-01-01

    Diosgenin, a traditional Yam extraction, has been used in hormone replacement for menopausal women. We aimed to investigate the influences of diosgenin administration upon the MMP-2 and -9 activity and expression and reproductive hormones of ovariectomized (OVX) rats, a model of menopausal status. Seven-week old female Wistar rats with bilateral OVX or sham operation (controls) were divided and administered different dosages of diosgenin (0, 10, 50, or 100 mg/kg/day) for 8 weeks. Serum was then sampled for progesterone (P4) and estradiol (E2) assay and uterine horns harvested. Myometrial MMP-2 and -9 activity and expression were surveyed and myometrial collagen expression was also assayed. The results show higher body weight in OVX rats across the 8 weeks post surgery and no significant differences were noted among OVX or Sham rats with diosgenin supplements. There were lower P4 and E2 concentrations in OVX rats compared to Sham rats, and higher P4 concentration of Sham rats post diosgenin supplement. MMP-2 and -9 mRNA expression and activity was lower in OVX rats, although higher MMP-2 and lower MMP-9 activity/mRNA expression was observed in OVX rats post diosgenin supplementation. Collagen mRNA expression was higher in OVX rats compared to Sham controls, and diosgenin administration decreased collagen mRNA expression in OVX rats. In conclusion, diosgenin is associated with gelatinase expression and collagen metabolism in OVX rats. Diosgenin administration can partially reverse the effects of OVX upon MMP functions and hormone status. Adequate diosgenin supplement might modulate myometrial gelatinase expression and collagen metabolism in menopausal subjects. PMID:21814480

  5. 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

  6. Thermodynamics of the interaction between oxytocin and its myometrial receptor in sheep: a stepwise binding mechanism.

    PubMed

    Pliska, Vladimir; Folkers, Gerd; Spiwok, Vojtěch

    2014-09-01

    Entropy (ΔS), enthalpy (ΔH) and heat capacity (ΔCp) changes attending the oxytocin interaction with its two binding sites on myometrial cell membranes in sheep were derived from the temperature dependence of Kd values. The high affinity oxytocin site (Kd on the order of 10(-9)mol l(-1), 25 °C), ascribed to the oxytocin receptor (OXTR), is entropy-driven in the temperature range 0-37 °C. Enthalpy component prevails as a driving force in the binding to the low affinity site (Kd ≈ 10(-7)) within the higher temperature range. ΔCp values in both cases do not differ significantly from zero but become highly relevant in the presence of a GTP analog (10(-4)M GTP-γS). Under these conditions, ΔCp in the low site interaction becomes negative and ΔS is shifted toward negative values (enthalpy drift); ΔCp of the high affinity site rises to a high positive value and the interaction is even more strongly entropy driven. Atosiban, a competitive antagonist of oxytocin at OXTR displays a single significant binding site on myometrial cells (Kd about 10(-7)mol l(-1)). Thermodynamic profiles of atosiban and the low affinity oxytocin site show conspicuous similarities, indicating that the inhibitor is bound to the low affinity site, and not, with a lower affinity, to the putative receptor protein. It is suggested that the interaction of oxytocin with its responding system on myometrial membranes follows in two distinct steps that are likely to be associated with several independent binding domains in the GPCR receptor. PMID:25010721

  7. The role of prostaglandins for the coordination of myometrial forces during labour.

    PubMed

    Wiqvist, N; Bryman, I; Lindblom, B; Norström, A; Wikland, M

    1985-01-01

    Systematic studies using a superfusion technique for recording myometrial contractility in vitro have been conducted in our department to explore whether prostaglandins (PG) have a differential action on the different segments of the pregnant uterus and also whether the qualitative and quantitative response undergoes a change during spontaneous labour. Myometrial specimens were excised from the fundal area and from the lower uterine segment at elective caesarean section in the 39th week of pregnancy before commencement of labour and at acute caesarean section during ongoing labour. Before labour PGF2 alpha was without or had a very weak effect on upper segment preparations but was stimulatory on lower segment specimens. PGE2 and PGI2 generally induced a biphasic dose-dependent response (stimulation followed by inhibition). During spontaneous labour PGF2 alpha and PGE2 always stimulated upper segment preparations while the contractile activity of specimens from the lower segment was inhibited by PGE2, PGF2 alpha was generally without effect. PGI2 had the same biphasic action before as during labour. With all reservations for the validity of in vitro experiments, the results favour the hypothesis that initiation of labour in the human involves a qualitative shift in the myometrial reactivity to prostaglandins. These alterations may involve suppression of expulsive forces and perhaps some tightening of the lower uterine segment during pregnancy. Following initiation of labour there is a marked increase in the excitatory action of both PGE2 and PGF2 alpha in the fundal area while the lower uterine segment reacts in a way that favours dilatation. PMID:3893037

  8. Insect tricks: two-phasic foot pad secretion prevents slipping.

    PubMed

    Dirks, Jan-Henning; Clemente, Christofer J; Federle, Walter

    2010-04-01

    Many insects cling to vertical and inverted surfaces with pads that adhere by nanometre-thin films of liquid secretion. This fluid is an emulsion, consisting of watery droplets in an oily continuous phase. The detailed function of its two-phasic nature has remained unclear. Here we show that the pad emulsion provides a mechanism that prevents insects from slipping on smooth substrates. We discovered that it is possible to manipulate the adhesive secretion in vivo using smooth polyimide substrates that selectively absorb its watery component. While thick layers of polyimide spin-coated onto glass removed all visible hydrophilic droplets, thin coatings left the emulsion in its typical form. Force measurements of stick insect pads sliding on these substrates demonstrated that the reduction of the watery phase resulted in a significant decrease in friction forces. Artificial control pads made of polydimethylsiloxane showed no difference when tested on the same substrates, confirming that the effect is caused by the insects' fluid-based adhesive system. Our findings suggest that insect adhesive pads use emulsions with non-Newtonian properties, which may have been optimized by natural selection. Emulsions as adhesive secretions combine the benefits of 'wet' adhesion and resistance against shear forces. PMID:19755498

  9. Vasopressin regularizes the phasic firing pattern of rat hypothalamic magnocellular vasopressin neurons.

    PubMed

    Gouzènes, L; Desarménien, M G; Hussy, N; Richard, P; Moos, F C

    1998-03-01

    Vasopressin (AVP) magnocellular neurons of hypothalamic nuclei express specific phasic firing (successive periods of activity and silence), which conditions the mode of neurohypophyseal vasopression release. In situations favoring plasmatic secretion of AVP, the hormone is also released at the somatodendritic level, at which it is believed to modulate the activity of AVP neurons. We investigated the nature of this autocontrol by testing the effects of juxtamembrane applications of AVP on the extracellular activity of presumed AVP neurons in paraventricular and supraoptic nuclei of anesthetized rats. AVP had three effects depending on the initial firing pattern: (1) excitation of faintly active neurons (periods of activity of <10 sec), which acquired or reinforced their phasic pattern; (2) inhibition of quasi-continuously active neurons (periods of silences of <10 sec), which became clearly phasic; and (3) no effect on neurons already showing an intermediate phasic pattern (active and silent periods of 10-30 sec). Consequently, AVP application resulted in a narrower range of activity patterns of the population of AVP neurons, with a Gaussian distribution centered around a mode of 57% of time in activity, indicating a homogenization of the firing pattern. The resulting phasic pattern had characteristics close to those established previously for optimal release of AVP from neurohypophyseal endings. These results suggest a new role for AVP as an optimizing factor that would foster the population of AVP neurons to discharge with a phasic pattern known to be most efficient for hormone release. PMID:9465012

  10. 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. PMID:26156995

  11. 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

  12. Phasic Oscillations of Extracellular Potassium (Ko) in Pregnant Rat Myometrium

    PubMed Central

    Young, Roger C.; Goloman, Gabriela

    2013-01-01

    K-sensitive microelectrodes were used to measure K+ within the extracellular space (Ko) of pregnant rat myometrium. Contractile activity was monitored by measuring either force or bioelectrical signals. Single and double-barreled electrodes were used. Double-barreled electrodes allowed monitoring of electrical activity 15 microns from the site of Ko measurement. From double-barreled electrode experiments, the bioelectrical burst started first, and then Ko began to rise 0.6 ± 0.1 seconds later. This delay indicates that K+ leaves the cells in response to local electrical activity rather than vice versa. Four control experiments were performed to assess the influence of electrical artifacts caused by tissue motion on Ko values. When observed, artifacts were negative and transient, and hence would result in an underestimation of Ko rises. Artifacts were minimized when tissue motion was minimized by fixing the tissue at both ends. At 37°C, 7 single barreled experiments and 45 contractions were analyzed. Resting Ko was within 1 mM of bath K+ (5 mM) at the beginning and end of the experiments. Ko rose during the contraction, fell after the completion of the contraction, and normalized before the next contraction began. Peak Ko values observed during force production were 18.8 ± 5.9 mM, a value high enough to modulate tissue-level electrical activity. Ko required 15.7 ± 2.8 seconds to normalize halfway (t50). Six experiments expressing 38 contractions were performed at 24°C. The contraction period was longer at 24°C. Values for peak Ko (26.2 ± 9.9 mM) and t50 (29.8±16.2 sec) were both larger than at 37°C (p<0.0003 for both). The direct relationships between peak Ko, t50 and the contraction period, suggest elevations in Ko may modulate contraction frequency. The myometrial interstitial space appears to be functionally important, and Ko metabolism may participate in cell-cell interactions. PMID:23724127

  13. Heterogeneity of phasic cholinergic signaling in neocortical neurons.

    PubMed

    Gulledge, Allan T; Park, Susanna B; Kawaguchi, Yasuo; Stuart, Greg J

    2007-03-01

    Acetylcholine (ACh) is a neurotransmitter critical for normal cognition. Here we demonstrate heterogeneity of cholinergic signaling in neocortical neurons in the rat prefrontal, somatosensory, and visual cortex. Focal ACh application (100 muM) inhibited layer 5 pyramidal neurons in all cortical areas via activation of an apamin-sensitive SK-type calcium-activated potassium conductance. Cholinergic inhibition was most robust in prefrontal layer 5 neurons, where it relies on the same signal transduction mechanism (M1-like receptors, IP(3)-dependent calcium release, and SK-channels) as exists in somatosensory pyramidal neurons. Pyramidal neurons in layer 2/3 were less responsive to ACh, but substantial apamin-sensitive inhibitory responses occurred in deep layer 3 neurons of the visual cortex. ACh was only inhibitory when presented near the somata of layer 5 pyramidal neurons, where repetitive ACh applications generated discrete inhibitory events at frequencies of up to approximately 0.5 Hz. Fast-spiking (FS) nonpyramidal neurons in all cortical areas were unresponsive to ACh. When applied to non-FS interneurons in layers 2/3 and 5, ACh generated mecamylamine-sensitive nicotinic responses (38% of cells), apamin-insensitive hyperpolarizing responses, with or without initial nicotinic depolarization (7% of neurons), or no response at all (55% of cells). Responses in interneurons were similar across cortical layers and regions but were correlated with cellular physiology and the expression of biochemical markers associated with different classes of nonpyramidal neurons. Finally, ACh generated nicotinic responses in all layer 1 neurons tested. These data demonstrate that phasic cholinergic input can directly inhibit projection neurons throughout the cortex while sculpting intracortical processing, especially in superficial layers. PMID:17122323

  14. 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

  15. 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

  16. Attenuated Tonic and Enhanced Phasic Release of Dopamine in Attention Deficit Hyperactivity Disorder

    PubMed Central

    Badgaiyan, Rajendra D.; Sinha, Sampada; Sajjad, Munawwar; Wack, David S.

    2015-01-01

    It is unclear whether attention deficit hyperactive disorder (ADHD) is a hypodopaminergic or hyperdopaminergic condition. Different sets of data suggest either hyperactive or hypoactive dopamine system. Since indirect methods used in earlier studies have arrived at contradictory conclusions, we directly measured the tonic and phasic release of dopamine in ADHD volunteers. The tonic release in ADHD and healthy control volunteers was measured and compared using dynamic molecular imaging technique. The phasic release during performance of Eriksen’s flanker task was measured in the two groups using single scan dynamic molecular imaging technique. In these experiments volunteers were positioned in a positron emission tomography (PET) camera and administered a dopamine receptor ligand 11C-raclopride intravenously. After the injection PET data were acquired dynamically while volunteers either stayed still (tonic release experiments) or performed the flanker task (phasic release experiments). PET data were analyzed to measure dynamic changes in ligand binding potential (BP) and other receptor kinetic parameters. The analysis revealed that at rest the ligand BP was significantly higher in the right caudate of ADHD volunteers suggesting reduced tonic release. During task performance significantly lower ligand BP was observed in the same area, indicating increased phasic release. In ADHD tonic release of dopamine is attenuated and the phasic release is enhanced in the right caudate. By characterizing the nature of dysregulated dopamine neurotransmission in ADHD, the results explain earlier findings of reduced or increased dopaminergic activity. PMID:26422146

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

    PubMed

    Hiu, Takeshi; Farzampour, Zoya; 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; Steinberg, Gary K

    2016-02-01

    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. Differences in recruitment order of motor units in phasic and tonic flexion reflex in `spinal man'

    PubMed Central

    Grimby, Lennart; Hannerz, Jan

    1970-01-01

    The recruitment order of motoneurones in muscle contractions has been held to be largely constant and determined by the size of the cell. However, as shown in a previous investigation using electromyographic techniques, the order in which different motor units are activated during voluntary muscle contractions changes in normal human subjects on shifts from phasic to tonic contraction. In order to investigate these two types of activity also in cases in which the cerebral influence on the motoneurone pool is blocked, an analysis was made of the recruitment order in phasic and tonic flexion reflexes in 10 patients with total interruption of the spinal cord. The following four principles were found to apply and presumed to be generally valid for the isolated human spinal cord: (1) in the phasic exteroceptive reflex, the order of recruitment varies despite application of a standardized stimulus; (2) in the tonic reflex, the first unit to be recruited is usually the same even with widely different types of stimuli; (3) a shift from phasic to tonic reflex activation may result in considerable changes in recruitment order; (4) after facilitation by a subliminal long-lasting stimulus, the first unit to be recruited in the phasic reflex is also the first to be recruited in the tonic reflex. It is suggested that a tonic influence on the motoneurone pool is required for the presupposed constancy of the recruitment order. Images PMID:5478941

  19. 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

  20. Cyclic mechanical stretching and interleukin-1alpha synergistically up-regulate prostacyclin secretion in cultured human uterine myometrial cells.

    PubMed

    Korita, D; Itoh, H; Sagawa, N; Yura, S; Yoshida, M; Kakui, K; Takemura, M; Nuamah, M A; Fujii, S

    2004-03-01

    Prostacyclin (PGI2), a potent uterine smooth muscle relaxant, is postulated to be a major prostaglandin (PG) secreted from the human myometrium. PGI2 metabolite concentrations in the maternal plasma were reported to be elevated during pregnancy, especially during labor. Recently, we developed cultured human myometrial cells from pregnant women and reported that cyclic mechanical stretching mimicking labor increased PGI2 secretion from these cells by up-regulating PGI2 synthase promoter activities. Since elevation of cervical/vaginal interleukin-1alpha (IL-1alpha) concentrations is also a characteristic feature of delivery, and IL-1alpha is a known stimulator of PG synthesis, we investigated a possible synergistic effect of cyclic mechanical stretching and IL-1alpha on PGI2 production in cultured human myometrial cells. Treatment with IL-1alpha (10 ng/ml) significantly augmented (4- to 60-fold) the secretion of PGI2, prostaglandin E2 (PGE2), prostaglandin F2alpha (PGF2alpha) and thromboxane A2 (TXA2) from cultured human myometrial cells obtained from non-pregnant and pregnant women as well as in cultured human umbilical artery and cultured human coronary artery smooth muscle cells (p < 0.05 for all comparisons). However, labor-like cyclic mechanical stretching up-regulated IL-1alpha-augmented PGI2 secretion from myometrial cells obtained from non-pregnant and pregnant women 2.1- to 2.8-fold (p < 0.05 for all comparisons), but not PGE2, PGF2alpha nor TXA2. Moreover, such an augumentation of PGI2 secretion by cyclic mechanical stretching was not observed in cultured human umbilical artery nor in cultured human coronary artery smooth muscle cells. These results suggest that cyclic mechanical stretching by labor, in concert with IL-1alpha stimulation, contributes to the increase in myometrial PGI2 secretion during delivery. PMID:15255281

  1. Effect of nimesulide and indomethacin on contractility and the Ca2+ channel current in myometrial smooth muscle from pregnant women

    PubMed Central

    Sawdy, Robert; Knock, Gregory A; Bennett, Philip R; Poston, Lucilla; Aaronson, Philip I

    1998-01-01

    The non-steroidal anti-inflammatory drug (NSAID) indomethacin inhibits both constitutive and inducible forms of cyclo-oxygenase (COX-1 and COX-2, respectively), while nimesulide is a selective COX-2 inhibitor. Uterine COX-2 is upregulated before and during term and pre-term labour, and prostaglandins play a crucial role in parturition. We therefore evaluated the effects of these drugs on myometrial contractility and the voltage-gated Ca2+ channel current in tissue strips and isolated human myometrial smooth muscle cells (HMSMC) from myometrial biopsies taken with informed consent from women undergoing caesarean section at term (not in labour).Nimesulide and indomethacin caused almost complete inhibition of spontaneous myometrial contractions at concentrations of 100 and 300 μM, respectively. The Ca2+ channel current was inhibited in a concentration-dependent manner by both drugs, with a 40% reduction of the current at 100 μM nimesulide and 300 μM indomethacin. Nimesulide also accelerated the decay of the Ca2+ channel current.The inhibition of the Ca2+ channel current by 100 μM nimesulide and 300 μM indomethacin was unaffected by the presence of either PGF2α or PGE2 (30 μM), and was of similar magnitude whether 10 mM Ba2+ or 1.5 mM Ca2+ was used as the charge carrier.The concentrations of indomethacin and nimesulide required to suppress spontaneous contractility in human pregnant myometrium were much higher than those necessary to inhibit prostaglandin production. The results suggest that both nimesulide and indomethacin inhibit myometrial contractility via mechanisms independent of cyclo-oxygenase inhibition. Blockade of the Ca2+ current may contribute to this effect. PMID:9863649

  2. 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.

  3. Immunocytochemical analysis of proliferative activity of endometrial and myometrial cell populations in focal and stromal adenomyosis.

    PubMed

    Nepomnyashchikh, L M; Lushnikova, E L; Molodykh, O P; Pichigina, A K

    2013-08-01

    Immunocytochemical study has shown that Ki-67 antigen is detected in adenomyosis in both endometrial and myometrial cell populations (in the eutopic and ectopic endometrial glandular epithelium, stromal cells, smooth muscle cells, and vascular endotheliocytes of the endometrium and myometrium), the label index differing significantly in different cell populations. The highest labeled cell index is found in the endometrial gland epitheliocytes in focal adenomyosis (23.2 ± 2.9%); in the stromal variant this index is by 2.8 times lower despite the fact that this variant is associated with endometrial glandular hyperplasia in the majority of cases. Proliferative activity of secretory epitheliocytes is significantly lower in both adenomyosis variants than in the normal eutopic endometrium. Stromal adenomyosis is characterized by 2-fold higher proliferative activity of the cytogenic stroma than that in focal adenomyosis. PMID:24143380

  4. 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.

  5. [Change in phospholipid content in platelets, immunocompetent cells and myometrial tissue in patients with internal endometriosis].

    PubMed

    Damirov, M M; Kulakov, V I; Sliusra', N N; Bakuleva, L P; Kargapolov, A V

    1994-01-01

    A method of flow horizontal chromatography has been developed permitting investigation of blood and tissue cellular phospholipids ruling out lipid peroxidation effects on cellular membranes. Phospholipid levels of blood and myometrial tissue cells were measured by this method in 67 patients with histologically verified internal endometriosis. Phospholipid and phosphatidyl inosite levels in platelets and immunocompetent cells of these patients reliably differed from those in healthy women. Phosphatidyl inosite levels of heterotopic endometrial tissue was increased by 1.4 times vs. the norm on an average. In parallel with this, a reliable change of phosphatidyl cholines and inosites levels in endometriosis foci were detected as against their levels in intact tissue. The authors suggest a method for the diagnosis of internal endometriosis by phosphatidyl inosite levels in blood lymphocytes. PMID:8209956

  6. Stro-1/CD44 as putative human myometrial and fibroid stem cell markers

    PubMed Central

    Mas, Aymara; Nair, Sangeeta; Laknaur, Archana; Simón, Carlos; Diamond, Michael P.; Al-Hendy, Ayman

    2015-01-01

    Objective To identify and characterize myometrial/fibroid stem cells by specific stem cell markers in human myometrium, and to better understand the stem cell contribution in the development of uterine fibroids. Design Prospective experimental human and animal study. Setting University research laboratory. Patients Women undergoing hysterectomy for treatment of symptomatic uterine fibroids. Animals Female NOD/SCID/IL-2Rγnull mice. Interventions Identification and isolation of stem cells from human fibroids (F) and adjacent myometrium (MyoF) tissues using Stro-1/CD44 specific surface markers. Main Outcome Measures Flow cytometry, semi- quantitative polymerase chain reaction, clonogenicity assays, cell culture, molecular analysis, immunocyto- histochemistry, in vitro differentiation, and xenotransplantation assays. Results Using Stro-1/CD44 surface markers, we were able to isolate stem cells from MyoF and F tissues. The undifferentiated status of isolated cells was confirmed by the expression of ABCG2 transporter, as well as additional stem cell markers OCT4, NANOG and GDB3, and the low expression of steroid receptors ERα and PR-A/PR-B. Mesodermal cell origin was established by the presence of typical mesenchymal markers (CD90, CD105, and CD73) and absence of hematopoietic stem cell markers (CD34, CD45), and confirmed by the ability of these cells to differentiate in vitro into adipocytes, osteocytes and chondrocytes. Finally, their functional capability to form fibroid-like lesions was established in xenotransplantation mouse model. The injected cells labeled with superparamagnetic iron oxide (SPIO) were tracked by both magnetic resonance imaging (MRI) and fluorescence imaging, thus demonstrating the regenerative potential of putative fibroid stem cells in vivo. Conclusion We have demonstrated that Stro-1/CD44 can be used as specific surface markers to enrich a subpopulation of myometrial/fibroids cells, exhibiting key features of stem/progenitor cells. These

  7. 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

  8. 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

  9. 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

  10. 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

  11. Stimulus change detection in phasic auditory units in the frog midbrain: frequency and ear specific adaptation

    PubMed Central

    Ponnath, Abhilash; Hoke, Kim L.

    2013-01-01

    Neural adaptation, a reduction in the response to a maintained stimulus, is an important mechanism for detecting stimulus change. Contributing to change detection is the fact that adaptation is often stimulus specific: adaptation to a particular stimulus reduces excitability to a specific subset of stimuli, while the ability to respond to other stimuli is unaffected. Phasic cells (e.g., cells responding to stimulus onset) are good candidates for detecting the most rapid changes in natural auditory scenes, as they exhibit fast and complete adaptation to an initial stimulus presentation. We made recordings of single phasic auditory units in the frog midbrain to determine if adaptation was specific to stimulus frequency and ear of input. In response to an instantaneous frequency step in a tone, 28 % of phasic cells exhibited frequency specific adaptation based on a relative frequency change (delta-f = ±16 %). Frequency specific adaptation was not limited to frequency steps, however, as adaptation was also overcome during continuous frequency modulated stimuli and in response to spectral transients interrupting tones. The results suggest that adaptation is separated for peripheral (e.g., frequency) channels. This was tested directly using dichotic stimuli. In 45 % of binaural phasic units, adaptation was ear specific: adaptation to stimulation of one ear did not affect responses to stimulation of the other ear. Thus, adaptation exhibited specificity for stimulus frequency and lateralization at the level of the midbrain. This mechanism could be employed to detect rapid stimulus change within and between sound sources in complex acoustic environments. PMID:23344947

  12. 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

  13. 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

  14. Redefining Stage I Endometrial Cancer: Incorporating Histology, a Binary Grading System, Myometrial Invasion, and Lymph Node Assessment

    PubMed Central

    Barlin, Joyce N.; Soslow, Robert A.; Lutz, Megan; Zhou, Qin C.; St Clair, Caryn M.; Leitao, Mario M.; Iasonos, Alexia; Hensley, Martee L.; Barakat, Richard R.; Matias-Guiu, Xavier; Abu-Rustum, Nadeem R.

    2015-01-01

    Objective We propose a new staging system for stage I endometrial cancer and compare its performance to the 1988 and 2009 International Federation of Gynecology and Obstetrics (FIGO) systems. Methods We analyzed patients with 1988 FIGO stage I endometrial cancer from January 1993 to August 2011. Low-grade carcinoma consisted of endometrioid grade 1 to grade 2 lesions. High-grade carcinoma consisted of endometrioid grade 3 or nonendometrioid carcinomas (serous, clear cell, and carcinosarcoma). The proposed system is as follows: IA Low-grade carcinoma with less than half myometrial invasion IA1 Negative nodes IA2 No nodes removed IB High-grade carcinoma with no myometrial invasion IB1 Negative nodes IB2 No nodes removed IC Low-grade carcinoma with half or greater myometrial invasion IC1 Negative nodes IC2 No nodes removed ID High-grade carcinoma with any myometrial invasion ID1 Negative nodes ID2 No nodes removed Results Data from 1843 patients were analyzed. When patients were restaged with our proposed system, the 5-year overall survival significantly differed (P < 0.001): IA1, 96.7%; IA2, 92.2%; IB1, 92.2%; IB2, 76.4%; IC1, 83.9%; IC2, 78.6%; ID1, 81.1%; and ID2, 68.8%. The bootstrap-corrected concordance probability estimate for the proposed system was 0.627 (95% confidence interval, 0.590–0.664) and was superior to the concordance probability estimate of 0.530 (95% confidence interval, 0.516–0.544) for the 2009 FIGO system. Conclusions By incorporating histological subtype, grade, myometrial invasion, and whether lymph nodes were removed, our proposed system for stage I endometrial cancer has a superior predictive ability over the 2009 FIGO staging system and provides a novel binary grading system (low-grade including endometrioid grade 1–2 lesions; high-grade carcinoma consisting of endometrioid grade 3 carcinomas and nonendometrioid carcinomas). PMID:24126219

  15. Ultrastructural features of endometrial-myometrial interface and its alteration in adenomyosis.

    PubMed

    Zhang, Ying; Zhou, Li; Li, Tin C; Duan, Hua; Yu, Pei; Wang, Hong Y

    2014-01-01

    The endometrial-myometrial interface (EMI) is a specific functional region of uterus. However, our knowledge on EMI ultrastructure both in normal uterus and adenomyosis is far from enough to understand its pathology. In this study, used the samples of EMI and outer myometrium (OM) from the adenomyosis hysterectomy specimens and the subjects from the control uteri, we prospectively compared the ultrastructure of myocytes from EMI and OM, the ultrastructural changes of EMI between the proliferative and secretory phases, and the ultrastructural difference of EMI between adenomyosis and the control group. In both adenomyosis and control group, there were differences in ultrastructure between myocytes from EMI and OM. Specifically, the myocytes from EMI were rich in organelles. In contrast, the myocytes from OM had abundant contractile structural components. In the proliferative phase, the myocytes from EMI in adenomyosis had significantly smaller cell and nucleus diameter than those from the control group, but in the secretory phase, the difference was not significant. In the control group, the various ultrastructural features of myocytes from EMI including the mean diameter of cell and nuclei and the myofilaments/cytoplasm ratio exhibited cyclical changes, but in adenomyosis, the normal cyclical changes were absent. In conclusions, there are significant ultrastructural differences between the myocytes from EMI and OM. The myocytes in women with adenomyosis were significantly different to the control subjects, primarily because the normal cyclical changes were absent. PMID:24817942

  16. Ultrastructural features of endometrial-myometrial interface and its alteration in adenomyosis

    PubMed Central

    Zhang, Ying; Zhou, Li; Li, Tin C; Duan, Hua; Yu, Pei; Wang, Hong Y

    2014-01-01

    The endometrial-myometrial interface (EMI) is a specific functional region of uterus. However, our knowledge on EMI ultrastructure both in normal uterus and adenomyosis is far from enough to understand its pathology. In this study, used the samples of EMI and outer myometrium (OM) from the adenomyosis hysterectomy specimens and the subjects from the control uteri, we prospectively compared the ultrastructure of myocytes from EMI and OM, the ultrastructural changes of EMI between the proliferative and secretory phases, and the ultrastructural difference of EMI between adenomyosis and the control group. In both adenomyosis and control group, there were differences in ultrastructure between myocytes from EMI and OM. Specifically, the myocytes from EMI were rich in organelles. In contrast, the myocytes from OM had abundant contractile structural components. In the proliferative phase, the myocytes from EMI in adenomyosis had significantly smaller cell and nucleus diameter than those from the control group, but in the secretory phase, the difference was not significant. In the control group, the various ultrastructural features of myocytes from EMI including the mean diameter of cell and nuclei and the myofilaments/cytoplasm ratio exhibited cyclical changes, but in adenomyosis, the normal cyclical changes were absent. In conclusions, there are significant ultrastructural differences between the myocytes from EMI and OM. The myocytes in women with adenomyosis were significantly different to the control subjects, primarily because the normal cyclical changes were absent. PMID:24817942

  17. Prolonged Pregnancy in Women Is Associated With Attenuated Myometrial Expression of Progesterone Receptor Co-Regulator Krüppel-Like Factor 9

    PubMed Central

    Pabona, John Mark P.; Zhang, Daying; Ginsburg, David S.; Simmen, Frank A.

    2015-01-01

    Context: Late-term pregnancy may lead to maternal and neonatal morbidity and mortality. Mice null for the progesterone receptor co-regulator Krüppel-like Factor 9 (KLF9) exhibit delayed parturition and increased incidence of neonatal deaths. Objective: Our aim is to evaluate the contribution of myometrial KLF9 to human parturition. Design: Myometrial biopsies were obtained from women with term (>37 to ≤41 wk) and late-term (>41 wk) pregnancies during cesarean delivery and assessed for gene and protein expression. Human myometrial cells transfected with nontargeting or KLF9 small interfering RNAs (siRNA) were treated with the progesterone antagonist RU486 and analyzed for pro-inflammatory chemokine/cytokine gene expression. Setting: The study took place in a University-affiliated tertiary care hospital and University research laboratory. Patients: Term patients (n = 8) were in spontaneous active labor whereas late-term patients (n = 5) were either in or were induced to active labor, prior to elective cesarean delivery. Outcome Measures: Steroid hormone receptor, contractility, and inflammation-associated gene expression in myometrial biopsies and in siKLF9-transfected, RU486-treated human myometrial cells was associated with KLF9 expression levels. Results: Myometrium from women with late-term pregnancy showed lower KLF9, total PGR, and PGR-A/PGR-B isoform expression. Transcript levels of select chemokines/cytokines were up- (CSF3, IL1, IL12A, TGFB2) and down- (CCL3, CCL5, CXCL1, CXCL5, IL15) regulated in late-term relative to term myometrium. Knock-down of KLF9 expression in RU486-treated human myometrial cells modified the expression of PGR and labor-associated cytokines, relative to control siRNA-treated cells. Conclusions: Myometrial KLF9 may contribute to the onset of human parturition through its regulation of PGR expression and inflammatory signaling networks. PMID:25313913

  18. 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. PMID:25771128

  19. 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

  20. Greater Sustained Anxiety but Not Phasic Fear in Women Compared to Men

    PubMed Central

    Grillon, Christian

    2009-01-01

    Startle reflex studies in rodents indicate that female are more reactive than rats in experimental models of sustained anxiety but not in models of phasic fear (Toufexis, 2007). This study examined evidence for a similar effect in humans. Participants were exposed to three conditions, (1) predictable aversive shocks signaled by a cue, (2) unpredictable shocks, and (3) no shocks. Acoustic startle stimuli were delivered regularly across conditions. Phasic startle potential to the threat cue in the predictable condition was not affected by sex. In contrast, and consistent with basic research, the sustained increase in startle in the predictable and unpredictable conditions was greater in women compared to men. Animal studies suggest that such an effect may be mediated by the effects of sexual dimorphism in limbic structures, including the bed nucleus of the stria terminalis. However, psychosocial factors may also contribute to this effect. PMID:18540756

  1. Disruption of NMDAR-dependent burst firing by dopamine neurons provides selective assessment of phasic dopamine-dependent behavior.

    PubMed

    Zweifel, Larry S; Parker, Jones G; Lobb, Collin J; Rainwater, Aundrea; Wall, Valerie Z; Fadok, Jonathan P; Darvas, Martin; Kim, Min J; Mizumori, Sheri J Y; Paladini, Carlos A; Phillips, Paul E M; Palmiter, Richard D

    2009-05-01

    Midbrain dopamine (DA) neurons fire in 2 characteristic modes, tonic and phasic, which are thought to modulate distinct aspects of behavior. However, the inability to selectively disrupt these patterns of activity has hampered the precise definition of the function of these modes of signaling. Here, we addressed the role of phasic DA in learning and other DA-dependent behaviors by attenuating DA neuron burst firing and subsequent DA release, without altering tonic neural activity. Disruption of phasic DA was achieved by selective genetic inactivation of NMDA-type, ionotropic glutamate receptors in DA neurons. Disruption of phasic DA neuron activity impaired the acquisition of numerous conditioned behavioral responses, and dramatically attenuated learning about cues that predicted rewarding and aversive events while leaving many other DA-dependent behaviors unaffected. PMID:19342487

  2. Phasic and sustained fear in humans elicits distinct patterns of brain activity

    PubMed Central

    Alvarez, Ruben P.; Chen, Gang; Bodurka, Jerzy; Kaplan, Raphael; Grillon, Christian

    2011-01-01

    Aversive events are typically more debilitating when they occur unpredictably than predictably. Studies in humans and animals indicate that predictable and unpredictable aversive events can induce phasic and sustained fear, respectively. Research in rodents suggests that anatomically related but distinct neural circuits may mediate phasic and sustained fear. We explored this issue in humans by examining threat predictability in three virtual reality contexts, one in which electric shocks were predictably signaled by a cue, a second in which shocks occurred unpredictably but never paired with a cue, and a third in which no shocks were delivered. Evidence of threat-induced phasic and sustained fear was presented using fear ratings and skin conductance. Utilizing recent advances in functional magnetic resonance imaging (fMRI), we were able to conduct whole-brain fMRI at relatively high spatial resolution and still have enough sensitivity to detect transient and sustained signal changes in the basal forebrain. We found that both predictable and unpredictable threat evoked transient activity in the dorsal amygdala, but that only unpredictable threat produced sustained activity in a forebrain region corresponding to the bed nucleus of the stria terminalis complex. Consistent with animal models hypothesizing a role for the cortex in generating sustained fear, sustained signal increases to unpredictable threat were also found in anterior insula and a frontoparietal cortical network associated with hypervigilance. In addition, unpredictable threat led to transient activity in the ventral amygdala–hippocampal area and pregenual anterior cingulate cortex, as well as transient activation and subsequent deactivation of subgenual anterior cingulate cortex, limbic structures that have been implicated in the regulation of emotional behavior and stress responses. In line with basic findings in rodents, these results provide evidence that phasic and sustained fear in humans may

  3. Phasic respiratory modulation of pharyngeal collapsibility via neuromuscular mechanisms in rats

    PubMed Central

    Cao, Ying; McGuire, Michelle; Liu, Chun; Malhotra, Atul

    2012-01-01

    Obstructive sleep apnea patients experience recurrent upper airway (UA) collapse due to decreases in the UA dilator muscle activity during sleep. In contrast, activation of UA dilators reduces pharyngeal critical pressure (Pcrit, an index of pharyngeal collapsibility), suggesting an inverse relationship between pharyngeal collapsibility and dilator activity. Since most UA muscles display phasic respiratory activity, we hypothesized that pharyngeal collapsibility is modulated by respiratory drive via neuromuscular mechanisms. Adult male Sprague-Dawley rats were anesthetized, vagotomized, and ventilated (normocapnia). In one group, integrated genioglossal activity, Pcrit, and maximal airflow (Vmax) were measured at three expiration and five inspiration time points within the breathing cycle. Pcrit was closely and inversely related to phasic genioglossal activity, with the value measured at peak inspiration being the lowest. In other groups, the variables were measured during expiration and peak inspiration, before and after each of five manipulations. Pcrit was 26% more negative (−15.0 ± 1.0 cmH2O, −18.9 ± 1.2 cmH2O; n = 23), Vmax was 7% larger (31.0 ± 1.0 ml/s, 33.2 ± 1.1 ml/s), nasal resistance was 12% bigger [0.49 ± 0.05 cmH2O/(ml/s), 0.59 ± 0.05 cmH2O/(ml/s)], and latency to induced UA closure was 14% longer (55 ± 4 ms, 63 ± 5 ms) during peak inspiration vs. expiration (all P < 0.005). The expiration-inspiration difference in Pcrit was abolished with neuromuscular blockade, hypocapnic apnea, or death but was not reduced by the superior laryngeal nerve transection or altered by tracheal displacement. Collectively, these results suggest that pharyngeal collapsibility is moment-by-moment modulated by respiratory drive and this phasic modulation requires neuromuscular mechanisms, but not the UA negative pressure reflex or tracheal displacement by phasic lung inflation. PMID:22052868

  4. 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

  5. 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

  6. Phasic motor activity reduction occurring with horizontal rapid eye movements during active sleep in human.

    PubMed

    Kohyama, J; Shimohira, M; Hasegawa, T; Kouji, T; Iwakawa, Y

    1995-01-01

    We describe the phasic reduction of motor activity occurring with horizontal rapid eye movements (REMs) during active sleep in 15 children (12 healthy children and 3 patients with severe brain damage). A REM-related decrease in intercostal muscle activity was demonstrated by averaging integrated surface electromyograms. In the healthy subjects, this reduction had a mean latency from the REM onset of 37.1 ms and a duration of 225.9 ms. This phenomenon was also observed in the 3 patients who had lost cerebral function. We hypothesized a brainstem origin for the effect. A REM-related mentalis muscle activity loss, detected by averaging mentalis muscle twitches, was observed in 10 healthy children among the subjects. This loss began at 59.1 ms before the onset of REMs and lasted for 230.2 ms on average. In addition, a transient decrease in integrated REM activity surrounding mentalis muscle twitches (a twitch-related reduction of REMs) was observed. We discuss the similarity between REM-related phasic reduction of muscle activity obtained for intercostal and mentalis muscles and pontogeniculo-occipital (PGO) wave-related inhibitory postsynaptic potentials reported for feline lumbar and trigeminal motoneurons, respectively. We then assume the presence of a phasic event generator, functioning during active sleep in healthy humans, which triggers at least three generators; that is, the generator of PGO waves (or REMs), motor inhibition, and of motor excitation including muscle twitches. PMID:8751071

  7. 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

  8. 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. PMID:27095087

  9. Sensitivity of transformed (phasic to tonic) motor neurons to the neuromodulator 5-HT.

    PubMed

    Griffis, B; Bonner, P; Cooper, R L

    2000-12-01

    Long-term adaptation resulting in a 'tonic-like' state can be induced in phasic motor neurons of the crayfish, Procambarus clarkii, by daily low-frequency stimulation [Lnenicka, G.A., Atwood, H.L., 1985b. Long-term facilitation and long-term adaptation at synapses of a crayfish phasic motoneuron. J. Neurobiol. 16, 97-110]. To test the hypothesis that motor neurons undergoing adaptation show increased responses to the neuromodulator serotonin (5-HT), phasic motor neurons innervating the deep abdominal extensor muscles of crayfish were stimulated at 2.5 Hz, 2 h/day, for 7 days. One day after cessation of conditioning, contralateral control and conditioned motor neurons of the same segment were stimulated at 1 Hz and the induced excitatory post-synaptic potentials (EPSPs) were recorded from DEL(1) muscle fibers innervated by each motor neuron type. Recordings were made in saline without and with 100 nM 5-HT. EPSP amplitudes were increased by 5-HT exposure in all cases. Conditioned muscles exposed to 5-HT showed a 2-fold higher percentage of increase in EPSP amplitude than did control muscles. Thus, the conditioned motor neurons behaved like intrinsically tonic motoneurons in their response to 5-HT. While these results show that long-term adaptation (LTA) extends to 5-HT neuromodulation, no phenotype switch could be detected in the postsynaptic muscle. Protein isoform profiles, including the myosin heavy chains, do not change after 1 week of conditioning their innervating motor neurons. PMID:11154946

  10. Calcium-activated chloride currents prolongs the duration of contractions in pregnant rat myometrial tissue.

    PubMed

    Young, Roger C; Bemis, Adam

    2009-08-01

    We investigated the importance of pharmacologically blocking calcium-activated chloride (I(Cl(Ca))) and L-type calcium currents on isometric contractions of strips of D21 pregnant rat myometrial tissue, while simultaneously measuring the electrical activity of the tissue strips with extracellular contact electrodes. When measured with contact electrodes, the duration of the spiking activity directly reflects the duration of the tissue-level plateau potential. We correlated the number of spikes, durations of spiking activity, and the spiking frequencies with changes of the area under the force curves as a function of exposure to low doses of anthracene-9-carboxylate (9-AC, a non-specific Cl channel blocker), chlorotoxin (a specific I(Cl(Ca)) blocker) and nifedipine (an L-type calcium channel blocker). The area under the force curve was measured only during spiking electrical activity, thereby separating pharmacological effects on tissue relaxation from those that modulate force production. Blocking chloride channels reduced impulse, shortened the duration of spiking activity, and reduced the number of spikes generated in each contraction. This was observed without a change in the frequency of spike production or a reduction of peak force. Nifedipine reduced impulse, shortened the duration of spiking activity, and reduced the number of spikes. In contrast to chloride channel blockade, nifedipine reduced maximum spike frequency and peak force. Taken together, our data suggest that blocking L-type calcium channels reduces impulse directly by reducing peak force, and indirectly by reducing activation of I(Cl(Ca)) , which shortens the duration of the contraction. PMID:19380901

  11. 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

  12. Stretch-induced human myometrial cytokines enhance immune cell recruitment via endothelial activation

    PubMed Central

    Lee, Yu-Hui; Shynlova, Oksana; Lye, Stephen J

    2015-01-01

    Spontaneous term labour is associated with amplified inflammatory events in the myometrium including cytokine production and leukocyte infiltration; however, potential mechanisms regulating such events are not fully understood. We hypothesized that mechanical stretch of the uterine wall by the growing fetus facilitates peripheral leukocyte extravasation into the term myometrium through the release of various cytokines by uterine myocytes. Human myometrial cells (hTERT-HM) were subjected to static mechanical stretch; stretch-conditioned media was collected and analysed using 48-plex Luminex assay and ELISA. Effect of stretch-conditioned media on cell adhesion molecule expression of human uterine microvascular endothelial cells (UtMVEC-Myo) was detected by quantitative polymerase chain reaction (qPCR) and flow cytometry; functional assays testing leukocyte–endothelial interactions: adhesion of leukocytes to endothelial cells and transendothelial migration of calcein-labelled primary human neutrophils as well as migration of THP-1 monocytic cells were assessed by fluorometry. The current in vitro study demonstrated that mechanical stretch (i) directly induces secretion of multiple cytokines and chemokines by hTERT-HM cells (IL-6, CXCL8, CXCL1, migration inhibitory factor (MIF), VEGF, G-CSF, IL-12p70, bFGF and platelet-derived growth factor subunit B (PDGF-bb), P<0.05); stretch-induced cytokines (ii) enhance leukocyte adhesion to the endothelium of the surrounding uterine microvasculature by (iii) inducing the expression of endothelial cell adhesion molecules and (iv) directing the transendothelial migration of peripheral leukocytes. (vi) Chemokine-neutralizing antibodies and broad-spectrum chemokine inhibitor block leukocyte migration. Our data provide a proof of mechanical regulation for leukocyte recruitment from the uterine blood vessels to the myometrium, suggesting a putative mechanism for the leukocyte infiltrate into the uterus during labour and postpartum

  13. Optimizing the ultrasound visualization of the endometrial-myometrial junction (EMJ)

    PubMed Central

    Votino, A.; Van den Bosch, T.; Installé, A.J.F.; Van Schoubroeck, D.; Kaijser, J.; Kacem, Y.; De Moor, B.; Van Pachterbeke, C.; Timmerman, D.

    2015-01-01

    Objectives: The aim of this study was to find the best 3D reconstruction technique to visualize the endometrial-myometrial junction (EMJ). Methods: Retrospective observational study on 240 stored 3D volumes of 80 patients. The first author reconstructed the 2D midcoronal image without volume contrast imaging (VCI), with VCI set at 4 mm and with VCI set at 2 mm. Three images per patient (240 images) were saved and integrated in the web-based electronic data capture software Clinical Data Miner (CDM) (http://cdm.esat.kuleuven.be). Five experienced gynaecologists analysed the images shown in random order. They scored the image quality (good, moderate, poor, insufficient) and described the EMJ of these images using IETA terminology (regular, irregular, interrupted, not defined). One of the examiners (CVP) also re-evaluated the same set of images after 12 days to assess intra-observer variability. Results: The use of VCI significantly improved the recorded subjective image quality. The Fleiss‘ kappa coefficient for evaluating the inter-observer variability of the EMJ description using coronal view without VCI, with VCI at 4 mm and VCI at 2 mm were 0.36 ± 0.05, 0.34 ± 0.05 and 0.42 ± 0.05, respectively. The corresponding figures for the intra-observer variability were 0.58 ± 0.08, 0.36 ± 0.08 and 0.68 ± 0.07, respectively. Discussion: In this study on 3D reconstructed coronal images of the uterine cavity, the 2 mm VCI slices gave the best quality images of the EMJ. PMID:25897372

  14. A prospective trial of postoperative vaginal radium/cesium for grade 1-2 less than 50% myometrial invasion and pelvic radiation therapy for grade 3 or deep myometrial invasion in surgical stage I endometrial adenocarcinoma

    SciTech Connect

    Piver, M.S.; Hempling, R.E. )

    1990-09-15

    A prospective trial was performed to evaluate the recurrence rate and 5-year disease-free survival rate in patients with surgical Stage I endometrial adenocarcinoma. Patients with Stage I, Grade 1 or 2 disease, less than 50% myometrial invasion, and no evidence of disease outside the corpus of the uterus were treated by hysterectomy and bilateral salpingo-oophorectomy and postoperative vaginal radium/cesium (Group 1). Patients with surgical Stage I, Grade 3 disease or deep myometrial invasion, and histologically negative paraaortic lymph nodes were treated with postoperative pelvic radiation therapy (5000-5040 cGY) (Group 2). Patients with malignant peritoneal cytologic findings also received progesterone therapy. Of the 92 Group 1 patients, there have been no recurrences and the 5-year estimated disease-free survival rate was 99%. Of the 41 Group 2 patients, there have been four (9.7%) recurrences but only one (2.4%) within the treated field (pelvis), and the 5-year estimated disease-free survival rate was 88%. Of the 133 patients, the 5-year estimated disease-free survival rate was 96%, and only one patient (0.7%) had a local pelvic recurrence. Of the 16 patients with malignant peritoneal cytologic findings who were treated with progesterone therapy, none has had a recurrence.

  15. 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

  16. Oxytocin and parturition: a role for increased myometrial calcium and calcium sensitization?

    PubMed

    Arthur, Patrice; Taggart, Michael J; Mitchell, Bryan F

    2007-01-01

    Preterm birth is associated with the majority of all death and chronic disability related to pregnancy, birth and the neonatal period. The costs to families and to the health care system are enormous. Current approaches to prevent or arrest preterm labour have been unsuccessful. This failure is largely based on our poor understanding of the regulation of the timing and maintenance of parturition. Oxytocin (OT) is the most potent known uterine stimulant. It is produced in the hypothalamus and secreted into the maternal bloodstream. However, OT also is produced within the uterine decidua in late gestation and the concentrations increase around the time of labour onset. The receptor for OT (OTR) is a G-protein coupled receptor linked through G alpha(q/11) to phospholipase C (PLC). Activation of PLC causes increased inositol trisphosphate (IP3) and diacyl glycerol (DAG). IP3 activates specific receptors in the sarcoplasmic reticulum to release Ca2+ into the cytosol. This may induce further influx of Ca2+ from the extracellular space and the increased Ca2+, after binding to calmodulin, activates myosin light chain kinase to phosphorylate myosin light chains (MLC) and cause contraction of the myocyte. DAG activates protein kinase C (PKC), several isoforms of which have been implicated in uterine contraction, but the substrates for this enzyme in the uterine myocyte are essentially unknown. Oxytocin may also cause "Ca2+-sensitization," a process whereby there is a greater contractile force generated from a given increase in cytosolic Ca2+, although the contribution of this process to myometrial contraction remains an area of debate. This phenomenon occurs mainly due to inhibition of myosin light chain phosphatase (MLCP), the enzyme that reverses the phosphorylation of MLC. There are several important potential mediators of this MLCP-inhibitory pathway in the myometrium, including the small monomeric G-protein RhoA, its downstream kinase Rho-associated kinase (ROK). and

  17. 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

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

    PubMed

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

    2016-02-01

    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. PMID:26575212

  19. 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

  20. 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

  1. Tonic and phasic drive to medullary respiratory neurons during periodic breathing

    PubMed Central

    Lovering, Andrew T.; Fraigne, Jimmy J.; Dunin-Barkowski, Witali L.; Vidruk, Edward H.; Orem, John M.

    2012-01-01

    It is unknown how central neural activity produces the repetitive termination and restart of periodic breathing (PB). We hypothesized that inspiratory and expiratory neural activities would be greatest during the waxing phase and least during the waning phase. We analyzed diaphragmatic and medullary respiratory neural activities during PB in intact unanesthetized adult cats. Diaphragmatic activity was increased and phasic during the waxing phase and was decreased and tonic during the waning phase. Activity of expiratory (n=21) and inspiratory (n=40) neurons was generally increased and phasic during the waxing phase and was decreased and more tonic during the waning phase. During apneas associated with PB, diaphragmatic activity was silent and most, but not all, inspiratory cells were inactive whereas most expiratory cells decreased activity but remained tonically active. We suggest that reduced strength of reciprocal inhibition, secondary to reduced respiratory drive, allows for simultaneous tonic activity of inspiratory and expiratory neurons of the central pattern generator, ultimately resulting in central apnea. PMID:22484379

  2. Phasic characteristics of arterial inflow and venous outflow of right ventricular myocardium in dogs.

    PubMed

    Hiramatsu, O; Kimura, A; Yada, T; Yamamoto, T; Ogasawara, Y; Goto, M; Tsujioka, K; Kajiya, F

    1992-05-01

    To clarify the characteristics and causes of phasic blood flow in coronary circulation of the right ventricle we measured blood velocities in peripheral portions of the right coronary artery and vein in dogs under three conditions: control, transient pulmonary stenosis, and isoproterenol administration. An optical fiber sensor of a laser Doppler velocimeter was fixed onto the vessels (150-500 microns OD) with cyanoacrylate. The phasic pattern of distal arterial velocity was compared with the proximal velocity in the right coronary artery measured with an ultrasound pulsed Doppler velocimeter. Systolic-to-total velocity area ratio in the small epicardial artery [0.38 +/- 0.03 (SE)] was found to be smaller than in the large epicardial artery (0.51 +/- 0.02, P less than 0.01), indicating a capacitive filling of the epicardial artery during systole. The velocity waveform in small right coronary veins was predominantly systolic; i.e., it increased with a rise of right ventricular pressure and decreased with right ventricular relaxation. Comparison of the waveforms during isoproterenol infusion and pulmonary stenosis indicates that contraction of the ventricle is more important than right ventricular systolic pressure in retarding arterial inflow and accelerating venous outflow. PMID:1590447

  3. HoxA13 Stimulates Myometrial Cells to Secrete IL-1β and Enhance the Expression of Contraction-Associated Proteins.

    PubMed

    Li, Haolong; Yu, Yue; Shi, Yao; Fazli, Ladan; Slater, Donna; Lye, Stephen; Dong, Xuesen

    2016-05-01

    Bipedalism in humans requires regionalization of myometrial function with a contracted lower uterine segment and a relaxed fundus during pregnancy to prevent fetal pressure on the cervix and reversal of this phenotype during labor. The HoxA13 gene is highly expressed in the lower uterine segment before term labor and regulates the regionalization of myometrium contractility. However, how HoxA13 regulates signal pathways to exert its functions remains unclear. Using a gene microarray technique, we profiled HoxA13 transcriptome in myometrial cells containing immune response genes (eg, IL-1β, IL-6, and IL-8) and contraction-associated proteins (CAPs) such as cyclooxygenase-2 (Cox-2) and connexin-43. IL-1β is responsible for mediating HoxA13 actions in up-regulating IL-6, IL-8, Cox-2, and connexin-43 expression. Blocking IL-1β with its inhibitor abolishes these HoxA13 actions. HoxA13-induced IL-1β stimulates the recruitment of activated THP-1 monocytes to myometrial cells, which in turn amplify the secretion of IL-1β, IL-6, and IL-8 through a mutual feed-forward loop between these cell types. As a result, Cox-2 expression is dramatically enhanced. These findings lead us to conclude that HoxA13 increases myometrial cell contractility by enhancing the secretion of IL-1β, resulting in an up-regulation of CAP and other proinflammatory cytokine expression. HoxA13-induced IL-1β in myometrial cells also prompts leukocyte recruitment and further amplifies CAP expression. PMID:26982635

  4. Phasic Contractions of the Mouse Vagina and Cervix at Different Phases of the Estrus Cycle and during Late Pregnancy

    PubMed Central

    Gravina, Fernanda S.; van Helden, Dirk F.; Kerr, Karen P.; de Oliveira, Ramatis B.; Jobling, Phillip

    2014-01-01

    Background/Aims The pacemaker mechanisms activating phasic contractions of vaginal and cervical smooth muscle remain poorly understood. Here, we investigate properties of pacemaking in vaginal and cervical tissues by determining whether: 1) functional pacemaking is dependent on the phase of the estrus cycle or pregnancy; 2) pacemaking involves Ca2+ release from sarcoplasmic/endoplasmic reticulum Ca2+-ATPase (SERCA) -dependent intracellular Ca2+ stores; and 3) c-Kit and/or vimentin immunoreactive ICs have a role in pacemaking. Methodology/Principal Findings Vaginal and cervical contractions were measured in vitro, as was the distribution of c-Kit and vimentin positive interstitial cells (ICs). Cervical smooth muscle was spontaneously active in estrus and metestrus but quiescent during proestrus and diestrus. Vaginal smooth muscle was normally quiescent but exhibited phasic contractions in the presence of oxytocin or the K+ channel blocker tetraethylammonium (TEA) chloride. Spontaneous contractions in the cervix and TEA-induced phasic contractions in the vagina persisted in the presence of cyclopiazonic acid (CPA), a blocker of the SERCA that refills intracellular SR Ca2+ stores, but were inhibited in low Ca2+ solution or in the presence of nifedipine, an inhibitor of L-type Ca2+channels. ICs were found in small numbers in the mouse cervix but not in the vagina. Conclusions/Significance Cervical smooth muscle strips taken from mice in estrus, metestrus or late pregnancy were generally spontaneously active. Vaginal smooth muscle strips were normally quiescent but could be induced to exhibit phasic contractions independent on phase of the estrus cycle or late pregnancy. Spontaneous cervical or TEA-induced vaginal phasic contractions were not mediated by ICs or intracellular Ca2+ stores. Given that vaginal smooth muscle is normally quiescent then it is likely that increases in hormones such as oxytocin, as might occur through sexual stimulation, enhance the

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

    PubMed

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

    2008-09-01

    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 (nu(max)) 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 nu(max) 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

  6. Mediation by the same muscarinic receptor subtype of phasic and tonic contractile activities in the rat isolated portal vein.

    PubMed Central

    Pfaffendorf, M.; Van Zwieten, P. A.

    1993-01-01

    1. The effects of several agonists on the phasic and tonic contractile responses to muscarinic receptor stimulation have been investigated in the rat portal vein in vitro. 2. Neither chemical denervation with 6-hydroxydopamine nor the presence of the alpha 1-adrenoceptor antagonist, prazosin, influenced the spontaneous or the stimulated myogenic activity of the portal vein. 3. Indomethacin and NG-nitro-L-arginine were used to investigate the influence of vasoactive factors in this preparation. They slightly increased the frequency and the amplitude of the spontaneous myogenic activity of the portal vein, respectively. NG-nitro-L-arginine but not indomethacin enhanced the maximal phasic response to carbachol. Both indomethacin and NG-nitro-L-arginine failed to influence the tonic response to carbachol. 4. Muscarinic agonists increased phasic activity according to the rank order of potency: acetylcholine > muscarine > methacholine > carbachol > aceclidine > bethanechol. These effects were superimposed on a sustained contracture at higher concentrations. Oxotremorine was more potent than arecoline in increasing the mechanical phasic activity, without inducing a sustained contracture. Pilocarpine and McN A343 were weak agonists, producing submaximal effects only on phasic activity. 5. The muscarinic antagonists AF-DX116, 4-diphenylacetoxy-N-methylpiperidine (4-DAMP), P-fluorohexahydrosiladiphenidol (pFHHSiD) and pirenzepine antagonized the phasic and tonic mechanical responses to carbachol. Although the tonic contracture was slightly more sensitive to all antagonists studied, the rank order of potency: 4-DAMP > pFHHSiD > pirenzepine > AF-DX 116 was the same for both types of responses, which is indicative of a M3-receptor subtype.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:8428203

  7. The effects of tamoxifen and estradiol on myometrial differentiation and organization during early uterine development in the CD1 mouse.

    PubMed

    Mehasseb, Mohamed K; Bell, S C; Habiba, M A

    2009-08-01

    We used a neonatal mouse model to examine the histogenesis of uterine adenomyosis, and to test whether adenomyosis is due to an abnormality in myometrial differentiation, or in extracellular matrix proteins expression. We also studied the effects of tamoxifen and estradiol on uterine development, myometrial differentiation, and organization. Female CD1 pups were treated with oral tamoxifen (1 mg/kg) (n=27) or estradiol (0.1 mg/kg) (n=24) from age 1 to 5 days. Uteri from control (n=27) and treated mice were obtained on days 2, 5, 10, 15, and 42 of age. We examined the sections histologically, using image analysis and immunohistochemistry for alpha-smooth muscle actin (alpha-SMA), desmin, vimentin, laminin, fibronectin, and estrogen receptor-alpha. Following tamoxifen exposure, all uteri showed adenomyosis by 6 weeks of age (seen as early as day 10). The inner myometrium showed thinning, lack of continuity, disorganization, and bundling. alpha-SMA expression was normal. Desmin expression normally showed a wave of maturation that was absent in tamoxifen-treated mice. In the estradiol group, adenomyosis was not observed. All uterine layers were normally developed, but hypertrophied. The inner myometrium retained its circular arrangement. There was no difference in the localization of laminin or fibronectin between groups (laminin expression was reduced in the tamoxifen treated uteri). Vimentin could not be detected in all groups. Our results suggest that the development of the inner myometrium is particularly sensitive to estrogen antagonism, and can be affected by steroid receptors modulation. Disruption of the inner myometrium may play a role in the development of uterine adenomyosis. PMID:19451194

  8. 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

  9. 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

  10. 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

  11. Tonic, phasic and cortical arousal in Gilles de la Tourette's syndrome.

    PubMed Central

    Bock, R D; Goldberger, L

    1985-01-01

    This study explored the hypothesis that Gilles de la Tourette's syndrome involves a disturbance in arousal modulation. The experimental group consisted of 20 unmedicated subjects with the Gilles de la Tourette's syndrome, and the control group of 20 subjects with chronic medical illnesses (haemophilia, von Willebrandt's disease and diabetes). There were differences between groups in the manner in which log conductance level changed over time during sound and light habituation experiments involving mild levels of stimulation with the Gilles de la Tourette group showing less change in arousal level over trials than the control group. No group differences were found in measures of phasic arousal, rate of spontaneous fluctuations and performance on two tasks that have been related to cortical arousal. It is suggested that the slower change in log conductance level in the Gilles de la Tourette group during the sound and light habituation experiments indicates that reticular activity is more persistent in these patients. PMID:3859582

  12. 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.

  13. 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

  14. The relationship between blood pressure variability, obesity and left atrial phasic function in hypertensive population.

    PubMed

    Tadic, Marijana; Cuspidi, Cesare; Ilic, Irena; Suzic-Lazić, Jelena; Zivanovic, Vladimir; Jozika, Ljilja; Celic, Vera

    2016-04-01

    We sought to investigate the relationship between blood pressure (BP) variability and left atrial (LA) phasic function assessed by volumetric and speckle tracking method in normal-weight, overweight and obese hypertensive patients. This cross-sectional study included 164 untreated hypertensive subjects who underwent a 24-h ambulatory BP monitoring and complete two-dimensional echocardiographic examination (2DE). All the patients were separated into three groups according to their body mass index (BMI): normal-weight patients (BMI < 25 kg/m(2)), overweight patients (25 ≤ BMI < 30 kg/m(2)), and obese patients (BMI ≥ 30 kg/m(2)). Daytime, nighttime and 24 h BP variability indices were higher in obese hypertensive subjects than in lean patients. Maximum and minimum LA volumes and volume indexes gradually and significantly increased, whereas pre-A LAV decreased, from normal-weight to obese subjects. Total and passive LA emptying fractions, representing LA reservoir and conduit function, gradually reduced from lean to obese individuals. Active LA EF, the parameter of LA booster pump function, increased in the same direction. Similar results were obtained by 2DE strain analysis. BP variability parameters were associated with structural, functional and mechanical parameters of LA remodeling in the whole study population. The parameters of LA reservoir function were negatively related with BP variability indices, whereas the parameters of LA pump function were positively related with BP variability indices. Obesity significantly impacts BP variability and LA phasic function in untreated hypertensive subjects. BP variability is associated with LA remodeling independent of BP, left ventricular systolic and diastolic function. PMID:26662267

  15. Lovastatin improves impaired synaptic plasticity and phasic alertness in patients with neurofibromatosis type 1

    PubMed Central

    2013-01-01

    Background Neurofibromatosis type 1 (NF1) is one of the most common genetic disorders causing learning disabilities by mutations in the neurofibromin gene, an important inhibitor of the RAS pathway. In a mouse model of NF1, a loss of function mutation of the neurofibromin gene resulted in increased gamma aminobutyric acid (GABA)-mediated inhibition which led to decreased synaptic plasticity and deficits in attentional performance. Most importantly, these defictis were normalized by lovastatin. This placebo-controlled, double blind, randomized study aimed to investigate synaptic plasticity and cognition in humans with NF1 and tried to answer the question whether potential deficits may be rescued by lovastatin. Methods In NF1 patients (n = 11; 19–44 years) and healthy controls (HC; n = 11; 19–31 years) paired pulse transcranial magnetic stimulation (TMS) was used to study intracortical inhibition (paired pulse) and synaptic plasticity (paired associative stimulation). On behavioural level the Test of Attentional Performance (TAP) was used. To study the effect of 200 mg lovastatin for 4 days on all these parameters, a placebo-controlled, double blind, randomized trial was performed. Results In patients with NF1, lovastatin revealed significant decrease of intracortical inhibition, significant increase of synaptic plasticity as well as significant increase of phasic alertness. Compared to HC, patients with NF1 exposed increased intracortical inhibition, impaired synaptic plasticity and deficits in phasic alertness. Conclusions This study demonstrates, for the first time, a link between a pathological RAS pathway activity, intracortical inhibition and impaired synaptic plasticity and its rescue by lovastatin in humans. Our findings revealed mechanisms of attention disorders in humans with NF1 and support the idea of a potential clinical benefit of lovastatin as a therapeutic option. PMID:24088225

  16. 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

  17. 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

  18. 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

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

    PubMed Central

    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. PMID:24834037

  20. 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

  1. 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.

  2. Cyclic mechanical stretch augments prostacyclin production in cultured human uterine myometrial cells from pregnant women: possible involvement of up-regulation of prostacyclin synthase expression.

    PubMed

    Korita, Daizo; Sagawa, Norimasa; Itoh, Hiroaki; Yura, Shigeo; Yoshida, Masahiro; Kakui, Kazuyo; Takemura, Maki; Yokoyama, Chieko; Tanabe, Tadashi; Fujii, Shingo

    2002-11-01

    Prostacyclin (PGI(2)), a potent smooth muscle relaxant, is a major prostaglandin secreted from human myometrium. The concentrations of PGI(2) metabolites in the maternal plasma were reported to be elevated during pregnancy, especially in labor. To clarify the mechanism in PGI(2) secretion from the myometrium, we first investigated the protein expression of cytosolic phospholipase A(2), cyclooxygenase (COX)-1, COX-2, and prostacyclin synthase (PGIS) in the human uterine myometrium at various gestational ages before labor. To elucidate the involvement of labor in the increase in PGI(2) production during labor, we next examined the effect of labor-like cyclic mechanical stretch on PGI(2) production by cultured human myometrial cells. Pregnancy specifically increased COX-1 and PGIS protein expression in the myometrial tissues before labor (P < 0.01 for both). Cyclic mechanical stretch augmented PGIS promoter activity, via activation of activator protein-1 site, and PGIS mRNA and protein expression in cultured human myometrial cells and resulted in a 3.5-fold increase in the concentration of 6-keto-prostaglandin F(1alpha), the stable metabolite of PGI(2), in the culture medium (P < 0.05). However, stretch did not affect the levels of prostaglandin E(2), prostaglandin F(2alpha), or thromboxane A(2) secreted into the same culture media. These results suggest that cyclic mechanical stretch during labor may contribute to the increase in the PGI(2) concentration in the maternal plasma during parturition. PMID:12414894

  3. Expression and function of myometrial PSF suggest a role in progesterone withdrawal and the initiation of labor.

    PubMed

    Xie, Ning; Liu, Liangliang; Li, Yunqing; Yu, Celeste; Lam, Stephanie; Shynlova, Oksana; Gleave, Martin; Challis, John R G; Lye, Stephen; Dong, Xuesen

    2012-08-01

    Progesterone (P4), acting through its receptor (PR), is essential for the maintenance of pregnancy. P4 acts by suppressing uterine contractility and the expression of contraction-associated proteins (CAP) such as connexin 43 (Cx43). P4 levels must be reduced or its actions blocked to allow the increased expression of CAP genes and the initiation of labor. Although the importance of progesterone in pregnancy has been known for about 80 yr, the fundamental mechanisms by which P4/PR maintains myometrial quiescence and by which this signaling is blocked at term labor remain to be determined. In this manuscript, we demonstrate that ligand-bound PR interacts with the Cx43 gene promoter through activator protein-1 transcription factors. We show that the ability of PR to repress Cx43 transcription is conferred through the recruitment of the PR coregulator, polypyrimidine tract binding protein-associated splicing factor (PSF), and the further recruitment of the yeast switch independent 3 homolog A/histone deacetylase corepressor complex. PSF expression is elevated during pregnancy but falls toward term as a result of increased mechanical stretch of the myometrium and a rise in the concentrations of circulating estrogen. These data together indicate that PSF is a critical regulator of P4/PR signaling and labor. We suggest that decreased PSF at term may result in a de-repression of PR transcriptional control of CAP genes and thereby contributes to a functional withdrawal of progesterone at term labor. PMID:22669741

  4. Human myometrial adrenergic receptors during pregnancy: identification of the alpha-adrenergic receptor by (/sup 3/H) dihydroergocryptine binding

    SciTech Connect

    Jacobs, M.M.; Hayashida, D.; Roberts, J.M.

    1985-07-15

    The radioactive alpha-adrenergic antagonist (/sup 3/H) dihydroergocryptine binds to particulate preparations of term pregnant human myometrium in a manner compatible with binding to the alpha-adrenergic receptor (alpha-receptor). (/sup 3/H) Dihydroergocryptine binds with high affinity (KD = 2 nmol/L and low capacity (receptor concentration = 100 fmol/mg of protein). Adrenergic agonists compete for (/sup 3/H) dihydroergocryptine binding sites stereo-selectively ((-)-norepinephrine is 100 times as potent as (+)-norepinephrine) and in a manner compatible with alpha-adrenergic potencies (epinephrine approximately equal to norepinephrine much greater than isoproterenol). Studies in which prazosin, an alpha 1-antagonist, and yohimbine, and alpha 2-antagonist, competed for (/sup 3/H) dihydroergocryptine binding sites in human myometrium indicated that approximately 70% are alpha 2-receptors and that 30% are alpha 1-receptors. (/sup 3/H) dihydroergocryptine binding to human myometrial membrane particulate provides an important tool with which to study the molecular mechanisms of uterine alpha-adrenergic response.

  5. Time-dependent changes in Ca2+ sensitivity during phasic contraction of canine antral smooth muscle.

    PubMed Central

    Ozaki, H; Gerthoffer, W T; Publicover, N G; Fusetani, N; Sanders, K M

    1991-01-01

    1. Relationships between cytosolic Ca2+ concentration ([Ca2+]cyt), myosin light chain (MLC) phosphorylation and muscle tension were examined in circular smooth muscle of canine gastric antrum. 2. Electrical slow waves induced a transient increase in [Ca2+]cyt and muscle tension. [Ca2+]cyt increased before the initiation of contraction and reached a maximum before the peak of the phasic contractions. Following the first Ca2+ transient, a second rise in [Ca2+]cyt was often observed. The second Ca2+ transient was of similar magnitude to the first, but only in some cases was this increase in [Ca2+]cyt associated with a second phase of contraction. Relaxation occurred more rapidly than the restoration of resting levels of [Ca2+]cyt. 3. Acetylcholine (ACh; 3 x 10(-7) M) increased the amplitude of Ca2+ transients, caused MLC phosphorylation and increased the force of contraction. The decay of contraction and MLC dephosphorylation preceded that of [Ca2+]cyt. 4. Increasing external K+ (to 25-40 mM) caused a sustained increase in [Ca2+]cyt, but little change in resting tension. This suggests that the Ca2+ sensitivity decreased as [Ca2+]cyt increased. Increasing K+ to 59.5 mM further increased the level of [Ca2+]cyt, induced MLC phosphorylation and caused a transient contraction. When normal levels of K+ were restored, the rates of MLC dephosphorylation and relaxation exceeded the rate of decay in [Ca2+]cyt. 5. Removal of external Ca2+ in depolarized muscles decreased [Ca2+]cyt below the resting level without affecting resting tension. Readmission of Ca2+ to depolarized muscles caused force to develop at [Ca2+]cyt levels below the original resting level, suggesting that Ca2+ sensitivity was increased when the resting level of [Ca2+]cyt was decreased. 6. The phosphatase inhibitor, calyculin-A (10(-6) M), induced tonic contraction and MLC phosphorylation without an increase in [Ca2+]cyt. During these contractures, electrical activity caused transient increases in [Ca2+]cyt and

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

    PubMed

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

    2016-07-01

    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

  7. 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

  8. Activity of phasic motor neurons partially transforms the neuronal and muscle phenotype to a tonic-like state.

    PubMed

    Cooper, R L; Warren, W M; Ashby, H E

    1998-07-01

    We present a model preparation, the crayfish, to investigate chronic stimulation effects in muscle fiber type and neuronal conversion from fast to slow. The results show a presynaptic alteration in transmitter release after 1 week of stimulation at 5 Hz for a 2-h daily regime. With the same stimulation paradigm, the muscle proteins displayed on a polyacrylamide gel only start to show changes after 3 weeks. The original phasic motoneurons within 1 week display an enhanced ability to resist synaptic depression, as do tonic motoneurons. The results show that identified phasic motoneurons and muscle fibers in the crayfish can be transformed to a toniclike state, and that the nerve terminals convert prior to the muscle fibers. Electrophysiological clinical measures indicating a change in transmitter release properties may not necessarily mean that the muscle fibers have fully adapted for long-lasting effects. This preparation allows stimulation conditions to be examined with ease. PMID:9626252

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

    PubMed

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

    2016-03-29

    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 GABAAreceptors 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

  10. Evaluation of animal models of obsessive-compulsive disorder: correlation with phasic dopamine neuron activity.

    PubMed

    Sesia, Thibaut; Bizup, Brandon; Grace, Anthony A

    2013-07-01

    Obsessive compulsive disorder (OCD) is a psychiatric condition defined by intrusive thoughts (obsessions) associated with compensatory and repetitive behaviour (compulsions). However, advancement in our understanding of this disorder has been hampered by the absence of effective animal models and correspondingly analysis of the physiological changes that may be present in these models. To address this, we have evaluated two current rodent models of OCD; repeated injection of dopamine D2 agonist quinpirole and repeated adolescent injection of the tricyclic agent clomipramine in combination with a behavioural paradigm designed to produce compulsive lever pressing. These results were then compared with their relative impact on the state of activity of the mesolimbic dopaminergic system using extracellular recoding of spontaneously active dopamine neurons in the ventral tegmental area (VTA). The clomipramine model failed to exacerbate compulsive lever pressing and VTA dopamine neurons in clomipramine-treated rats had mildly diminished bursting activity. In contrast, quinpirole-treated animals showed significant increases in compulsive lever pressing, which was concurrent with a substantial diminution of bursting activity of VTA dopamine neurons. Therefore, VTA dopamine activity correlated with the behavioural response in these models. Taken together, these data support the view that compulsive behaviours likely reflect, at least in part, a disruption of the dopaminergic system, more specifically by a decrease in baseline phasic dopamine signalling mediated by burst firing of dopamine neurons. PMID:23360787

  11. 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. PMID:18266521

  12. 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.

  13. 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

  14. Phasic dopamine release drives rapid activation of striatal D2-receptors

    PubMed Central

    Marcott, Pamela F; Mamaligas, Aphroditi A; Ford, Christopher P

    2014-01-01

    Summary Striatal dopamine transmission underlies numerous goal-directed behaviors. Medium spiny neurons (MSNs) are a major target of dopamine in the striatum. However, as dopamine does not directly evoke a synaptic event in MSNs, the time course of dopamine signaling in these cells remains unclear. To examine how dopamine release activates D2-receptors on MSNs, G-protein activated inwardly rectifying potassium (GIRK2; Kir 3.2) channels were virally overexpressed in the striatum and the resulting outward currents were used as a sensor of D2-receptor activation. Electrical and optogenetic stimulation of dopamine terminals evoked robust D2-receptor inhibitory post-synaptic currents (IPSCs) in GIRK2-expressing MSNs that occurred in under a second. Evoked D2-IPSCs could be driven by repetitive stimulation and were not occluded by background dopamine tone. Together, the results indicate that D2-receptors on MSNs exhibit functional low affinity and suggest that striatal D2-receptors can encode both tonic and phasic dopamine signals. PMID:25242218

  15. A psychophysiological study in humans using phasic colonic distension as a noxious visceral stimulus.

    PubMed

    Ness, T J; Metcalf, A M; Gebhart, G F

    1990-12-01

    Psychophysiological experiments were performed in 9 humans using constant-pressure, phasic, graded distention (30 sec, 20-70 mm Hg) of the sigmoid colon as a visceral stimulus. Reliable cardiovascular (pressor), respiratory and visceromotor responses in addition to reports of pressure/pain sensations were evoked by colonic distension in 8 of the 9 subjects. The pressure/pain sensations were referred to the lower abdomen, lower back and perineum and their intensity quantified using a visual analogue scale. Responses to colonic distension were graded and increased with repeated distensions at the same intensity (60 mm Hg). The area of referral as indicated by subject drawings increased with repeated distensions as did the intensity of the subjects' sensory and affective descriptors of the sensation. Five of the subjects differentiated between 'pressure' and 'pain' sensations evoked by colonic distension; the intensity of the 'pain' sensation accelerated during the distending stimulus whereas the 'pressure' sensation was typically stable or adapting during the distending stimulus. PMID:2293146

  16. 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

  17. Phasic dopamine release in the medial prefrontal cortex enhances stimulus discrimination.

    PubMed

    Popescu, Andrei T; Zhou, Michael R; Poo, Mu-Ming

    2016-05-31

    Phasic dopamine (DA) release is believed to guide associative learning. Most studies have focused on projections from the ventral tegmental area (VTA) to the striatum, and the action of DA in other VTA target regions remains unclear. Using optogenetic activation of VTA projections, we examined DA function in the medial prefrontal cortex (mPFC). We found that mice perceived optogenetically induced DA release in mPFC as neither rewarding nor aversive, and did not change their previously learned behavior in response to DA transients. However, repetitive temporal pairing of an auditory conditioned stimulus (CS) with mPFC DA release resulted in faster learning of a subsequent task involving discrimination of the same CS against unpaired stimuli. Similar results were obtained using both appetitive and aversive unconditioned stimuli, supporting the notion that DA transients in mPFC do not represent valence. Using extracellular recordings, we found that CS-DA pairings increased firing of mPFC neurons in response to CSs, and administration of D1 or D2 DA-receptor antagonists in mPFC during learning impaired stimulus discrimination. We conclude that DA transients tune mPFC neurons for the recognition of behaviorally relevant events during learning. PMID:27185946

  18. Phosphodiesterase types 3 and 4 regulate the phasic contraction of neonatal rat bladder smooth myocytes via distinct mechanisms.

    PubMed

    Zhai, Kui; Chang, Yan; Wei, Bin; Liu, Qinghua; Leblais, Véronique; Fischmeister, Rodolphe; Ji, Guangju

    2014-05-01

    Activation of the cyclic AMP (cAMP) pathway reduces bladder contractility. However, the role of phosphodiesterase (PDE) families in regulating this function is poorly understood. Here, we compared the contractile function of the cAMP hydrolyzing PDEs in neonatal rat bladder smooth myocytes. RT-PCR and Western blotting analysis revealed that several isoforms of PDE1-4 were expressed in neonatal rat bladder. While 8-methoxymethyl-3-isobutyl-1-methylxanthine (a PDE1 inhibitor) and BAY-60-7550 (a PDE2 inhibitor) had no effect on the carbachol-enhanced phasic contractions of bladder strips, cilostamide (Cil, a PDE3 inhibitor) and Ro-20-1724 (Ro, a PDE4 inhibitor) significantly reduced these contractions. This inhibitory effect of Ro was blunted by the PKA inhibitor H-89, while the inhibitory effect of Cil was strongly attenuated by the PKG inhibitor KT 5823. Application of Ro in single bladder smooth myocytes resulted in an increase in Ca(2+) spark frequency but a decrease both in Ca(2+) transients and in sarcoplasmic reticulum (SR) Ca(2+) content. In contrast, Cil had no effect on these events. Furthermore, Ro-induced inhibition of the phasic contractions was significantly blocked by ryanodine and iberiotoxin. Taken together, PDE3 and PDE4 are the main PDE isoforms in maintaining the phasic contractions of bladder smooth myocytes, with PDE4 being functionally more active than PDE3. However, their roles are mediated through different mechanisms. PMID:24463006

  19. 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

  20. Long chain polyunsaturated fatty acids alter oxytocin signaling and receptor density in cultured pregnant human myometrial smooth muscle cells.

    PubMed

    Kim, Paul Y; Zhong, Miao; Kim, Yoon-Sun; Sanborn, Barbara M; Allen, Kenneth G D

    2012-01-01

    Epidemiological studies and interventional clinical trials indicate that consumption of long chain n-3 polyunsaturated fatty acids (LC n-3 PUFA) such as docosahexaenoic acid (DHA) lengthen gestational duration. Although the mechanisms are not well understood, prostaglandins (PG) of the 2-series are known to play a role in the initiation and progress of labor. In animal studies, modest DHA provision has been shown to reduce placental and uterine PGE(2) and PGF(2α), matrix metalloproteinase (MMP)-2 and MMP-9 expression, and placental collagenase activity. However, modulation of PG biosynthesis may not account for all the effects of LC n-3 PUFAs in labor. We investigated one potential PG-independent mechanism of LC PUFA action using cultured pregnant human myometrial smooth muscle cells. Our goal was to characterize the effect of LC PUFA treatment on oxytocin signaling, a potent uterotonic hormone involved in labor. The addition of 10 µM-100 µM DHA or arachidonic acid (AA) to the culture media for 48 h resulted in dose dependent enrichment of these fatty acids in membrane lipid. DHA and AA significantly inhibited phosphatidylinositol turnover and [Ca(2+)](i) mobilization with oxytocin stimulation compared to bovine serum albumin control and equimolar oleic acid. DHA and AA significantly reduced oxytocin receptor membrane concentration without altering binding affinity or rate of receptor internalization. These findings demonstrate a role for LC n-3 PUFAs in regulation of oxytocin signaling and provide new insight into additional mechanisms pertaining to reports of dietary fish and fish oil consumption prolonging gestation. PMID:22848573

  1. The Effect of an Oxytocin Receptor Antagonist (Retosiban, GSK221149A) on the Response of Human Myometrial Explants to Prolonged Mechanical Stretch.

    PubMed

    Moraitis, Alexandros A; Cordeaux, Yolande; Charnock-Jones, D Stephen; Smith, Gordon C S

    2015-10-01

    Multiple pregnancy is a major cause of spontaneous preterm birth, which is related to uterine overdistention. The objective of this study was to determine whether an oxytocin receptor antagonist, retosiban (GSK221149A), inhibited the procontractile effect of stretch on human myometrium. Myometrial biopsies were obtained at term planned cesarean delivery (n = 12). Each biopsy specimen was dissected into 8 strips that were exposed in pairs to low or high stretch (0.6 or 2.4 g) in the presence of retosiban (1 μM) or vehicle (dimethylsulfoxide) for 24 hours. Subsequently, we analyzed the contractile responses to KCl and oxytocin in the absence of retosiban. We found that incubation under high stretch in vehicle alone increased the response of myometrial explants to both KCl (P = .007) and oxytocin (P = .01). However, there was no statistically significant effect of stretch when explants were incubated with retosiban (P = .3 and .2, respectively). Incubation with retosiban in low stretch had no statistically significant effect on the response to either KCl or oxytocin (P = .8 and >.9, respectively). Incubation with retosiban in high stretch resulted in a statistically significant reduction (median fold change, interquartile range, P) in the response to both KCl (0.74, 0.60-1.03, P = .046) and oxytocin (0.71, 0.53-0.91, P = .008). The greater the effect of stretch on explants from a given patient, the greater was the inhibitory effect of retosiban (r = -0.65, P = .02 for KCl and r= -0.73, P = .007 for oxytocin). These results suggest that retosiban prevented stretch-induced stimulation of human myometrial contractility. Retosiban treatment is a potential approach for preventing preterm birth in multiple pregnancy. PMID:26207346

  2. 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

  3. 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

  4. Influence of norepinephrine on the tonic and phasic depression of Vmax by nifedipine and verapamil in guinea pig ventricle.

    PubMed

    Woods, J P; West, T C

    1986-01-01

    Right ventricular strips from guinea pig hearts were used to study the interaction between norepinephrine (NE) and the Ca2+ channel blockers nifedipine and verapamil on maximal upstroke velocity (Vmax) of rapid depolarization in potassium-depolarized preparations. Barium ion (0.8 mM) was added to the bathing solution to restore excitability of the K+-depolarized tissue. Concentrations of verapamil (5 X 10(-7) M) and nifedipine (5 X 10(-8) M) were selected to produce optimal depression of Vmax under both tonic (rested) and phasic (pacing frequencies from 0.05 to 2.0 Hz) conditions. NE increased the tonic and phasic Vmax of control preparations in equal proportion at all stimulation frequencies. Thus, the physiological frequency dependence of Vmax was not altered by NE. NE (10(-6) M) produced an increase of 11.8 +/- 2.2% in the tonic Vmax of verapamil-treated preparations and an increase of 17.4 +/- 1.1% in the tonic Vmax of nifedipine-treated preparations. In each case the enhancement of Vmax by NE was proportional for both tonic and phasic conditions, thus showing no effect on the frequency-dependent action of either drug. In all cases, the NE-induced increase in Vmax was concentration dependent. Higher concentrations of NE thwarted the measurement of tonic Vmax due to the onset of spontaneous activity except in the presence of nifedipine (5 X 10(-8) M). The maximal concentration of NE that could be tolerated without the onset of spontaneous activity was directly related to the degree of tonic depression of Vmax induced by the Ca2+ channel blocking agent.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:2427818

  5. 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. PMID:26608340

  6. 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

  7. The action of the beta-agonist clenbuterol on protein metabolism in innervated and denervated phasic muscles.

    PubMed Central

    Maltin, C A; Hay, S M; Delday, M I; Lobley, G E; Reeds, P J

    1989-01-01

    1. Clenbuterol treatment in innervated and denervated phasic extensor digitorum longus, plantaris and gastrocnemius muscles from rats caused a significant increase in RNA and protein contents in all muscles except denervated extensor digitorum longus. 2. All muscles showed an increase in the fractional rate of protein synthesis (Ks) with clenbuterol, but the temporal response varied. 3. The data suggest that the effect of clenbuterol on protein metabolism in innervated muscles is muscle-type specific, and demonstrate the homology of response for denervated muscles. Images Fig. 1. PMID:2803256

  8. Phasic activity in the human erector spinae during repetitive hand movements.

    PubMed Central

    Zedka, M; Prochazka, A

    1997-01-01

    1. Phasic activity in the human back muscle erector spinae (ES) was studied during repetitive hand movements. The hand movements were elicited voluntarily by the subject or induced passively by the experimenter through a servomotor or through cyclical electrical stimulation of muscles acting about the wrist. The aim of the study was to determine whether the rhythmical activation of ES was of supraspinal, intersegmental or segmental origin. 2. When voluntary rhythmical hand movements were performed as fast as possible, cyclical ES EMG bursts occurred at the same frequency. This frequency was significantly higher than that reached when the task was to contract the back muscles as rapidly as possible. This suggests that the ES activity during the fast hand movements was not generated by direct commands descending to the ES muscles from the motor area of the cerebral cortex responsible for voluntary back muscle activation. 3. During imposed rhythmical hand movements, ES EMG bursts remained entrained to the hand movements, even when movement frequencies far exceeded those attainable voluntarily either for the hand or the back. This showed that ES EMG responses could be evoked by the hand movements even when these were not generated by descending neural commands. Two alternative mechanisms of ES activation were considered: (a) propriospinal transmission of afferent input entering the spinal cord from the upper extremity; (b) afferent input from ES and other trunk muscles, responding to local oscillations transmitted mechanically from the hand to the lower back. 4. Activation of ES via proprioceptive signals from the forearm was unlikely since (a) simultaneous electrical stimulation of wrist extensor and wrist flexor muscles did not result in repetitive ES EMG bursting; (b) cyclical vibration of the wrist extensors did not evoke ES EMG bursting; (c) when the forearm was constrained and the hand was moved passively, the lower trunk accelerations and cyclical ES EMG both

  9. Functional microstates within human REM sleep: first evidence from fMRI of a thalamocortical network specific for phasic REM periods.

    PubMed

    Wehrle, Renate; Kaufmann, Christian; Wetter, Thomas C; Holsboer, Florian; Auer, Dorothee P; Pollmächer, Thomas; Czisch, Michael

    2007-02-01

    High thalamocortical neuronal activity characterizes both, wakefulness and rapid eye movement (REM) sleep, but apparently this network fulfills other roles than processing external information during REM sleep. To investigate thalamic and cortical reactivity during human REM sleep, we used functional magnetic resonance imaging with simultaneous polysomnographic recordings while applying acoustic stimulation. Our observations indicate two distinct functional substates within general REM sleep. Acoustic stimulation elicited a residual activation of the auditory cortex during tonic REM sleep background without rapid eye movements. By contrast, periods containing bursts of phasic activity such as rapid eye movements appear characterized by a lack of reactivity to sensory stimuli. We report a thalamocortical network including limbic and parahippocampal areas specifically active during phasic REM periods. Thus, REM sleep has to be subdivided into tonic REM sleep with residual alertness, and phasic REM sleep with the brain acting as a functionally isolated and closed intrinsic loop. PMID:17328781

  10. 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.

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

    PubMed Central

    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

  12. 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

  13. 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

  14. [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

  15. 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. PMID:26320615

  16. Crosstalk between monocytes and myometrial smooth muscle in culture generates synergistic pro-inflammatory cytokine production and enhances myocyte contraction, with effects opposed by progesterone

    PubMed Central

    Rajagopal, S.P.; Hutchinson, J.L.; Dorward, D.A.; Rossi, A.G.; Norman, J.E.

    2015-01-01

    Both term and preterm parturition are characterized by an influx of macrophages and neutrophils into the myometrium and cervix, with co-incident increased peripheral blood monocyte activation. Infection and inflammation are strongly implicated in the pathology of preterm labour (PTL), with progesterone considered a promising candidate for its prevention or treatment. In this study, we investigated the effect of monocytes on myometrial smooth muscle cell inflammatory cytokine production both alone and in response to LPS, a TLR4 agonist used to trigger PTL in vivo. We also investigated the effect of monocytes on myocyte contraction. Monocytes, isolated from peripheral blood samples from term pregnant women, were cultured alone, or co-cultured with PHM1-41 myometrial smooth muscle cells, for 24 h. In a third set of experiments, PHM1-41 myocytes were cultured for 24 h in isolation. Cytokine secretion was determined by ELISA or multiplex assays. Co-culture of monocytes and myocytes led to synergistic secretion of pro-inflammatory cytokines and chemokines including IL-6, IL-8 and MCP-1, with the secretion being further enhanced by LPS (100 ng/ml). The synergistic secretion of IL-6 and IL-8 from co-cultures was mediated in part by direct cell–cell contact, and by TNF. Conditioned media from co-cultures stimulated contraction of PHM1-41 myocytes, and the effect was inhibited by progesterone. Both progesterone and IL-10 inhibited LPS-stimulated IL-6 and IL-8 secretion from co-cultures, while progesterone also inhibited chemokine secretion. These data suggest that monocytes infiltrating the myometrium at labour participate in crosstalk that potentiates pro-inflammatory cytokine secretion, an effect that is enhanced by LPS, and can augment myocyte contraction. These effects are all partially inhibited by progesterone. PMID:26002969

  17. Crosstalk between monocytes and myometrial smooth muscle in culture generates synergistic pro-inflammatory cytokine production and enhances myocyte contraction, with effects opposed by progesterone.

    PubMed

    Rajagopal, S P; Hutchinson, J L; Dorward, D A; Rossi, A G; Norman, J E

    2015-08-01

    Both term and preterm parturition are characterized by an influx of macrophages and neutrophils into the myometrium and cervix, with co-incident increased peripheral blood monocyte activation. Infection and inflammation are strongly implicated in the pathology of preterm labour (PTL), with progesterone considered a promising candidate for its prevention or treatment. In this study, we investigated the effect of monocytes on myometrial smooth muscle cell inflammatory cytokine production both alone and in response to LPS, a TLR4 agonist used to trigger PTL in vivo. We also investigated the effect of monocytes on myocyte contraction. Monocytes, isolated from peripheral blood samples from term pregnant women, were cultured alone, or co-cultured with PHM1-41 myometrial smooth muscle cells, for 24 h. In a third set of experiments, PHM1-41 myocytes were cultured for 24 h in isolation. Cytokine secretion was determined by ELISA or multiplex assays. Co-culture of monocytes and myocytes led to synergistic secretion of pro-inflammatory cytokines and chemokines including IL-6, IL-8 and MCP-1, with the secretion being further enhanced by LPS (100 ng/ml). The synergistic secretion of IL-6 and IL-8 from co-cultures was mediated in part by direct cell-cell contact, and by TNF. Conditioned media from co-cultures stimulated contraction of PHM1-41 myocytes, and the effect was inhibited by progesterone. Both progesterone and IL-10 inhibited LPS-stimulated IL-6 and IL-8 secretion from co-cultures, while progesterone also inhibited chemokine secretion. These data suggest that monocytes infiltrating the myometrium at labour participate in crosstalk that potentiates pro-inflammatory cytokine secretion, an effect that is enhanced by LPS, and can augment myocyte contraction. These effects are all partially inhibited by progesterone. PMID:26002969

  18. Age differences in high frequency phasic heart rate variability and performance response to increased executive function load in three executive function tasks

    PubMed Central

    Byrd, Dana L.; Reuther, Erin T.; McNamara, Joseph P. H.; DeLucca, Teri L.; Berg, William K.

    2015-01-01

    The current study examines similarity or disparity of a frontally mediated physiological response of mental effort among multiple executive functioning tasks between children and adults. Task performance and phasic heart rate variability (HRV) were recorded in children (6 to 10 years old) and adults in an examination of age differences in executive functioning skills during periods of increased demand. Executive load levels were varied by increasing the difficulty levels of three executive functioning tasks: inhibition (IN), working memory (WM), and planning/problem solving (PL). Behavioral performance decreased in all tasks with increased executive demand in both children and adults. Adults’ phasic high frequency HRV was suppressed during the management of increased IN and WM load. Children’s phasic HRV was suppressed during the management of moderate WM load. HRV was not suppressed during either children’s or adults’ increasing load during the PL task. High frequency phasic HRV may be most sensitive to executive function tasks that have a time-response pressure, and simply requiring performance on a self-paced task requiring frontal lobe activation may not be enough to generate HRV responsitivity to increasing demand. PMID:25798113

  19. 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. PMID:23353115

  20. Preferential enhancement of dopamine transmission within the nucleus accumbens shell by cocaine is attributable to a direct increase in phasic dopamine release events.

    PubMed

    Aragona, Brandon J; Cleaveland, Nathan A; Stuber, Garret D; Day, Jeremy J; Carelli, Regina M; Wightman, R Mark

    2008-08-27

    Preferential enhancement of dopamine transmission within the nucleus accumbens (NAc) shell is a fundamental aspect of the neural regulation of cocaine reward. Despite its importance, the nature of this effect is poorly understood. Here, we used fast-scan cyclic voltammetry to examine specific transmission processes underlying cocaine-evoked increases in dopamine transmission within the NAc core and shell. Initially, we examined altered terminal dopamine concentrations after global autoreceptor blockade. This was the first examination of autoreceptor regulation of naturally occurring phasic dopamine transmission and provided a novel characterization of specific components of dopamine neurotransmission. Comparison of increased dopamine signaling evoked by autoreceptor blockade and cocaine administration allowed robust resolution between increased frequency, concentration, and duration of phasic dopamine release events after cocaine delivery. Cocaine increased dopamine transmission by slowed uptake and increased concentration of dopamine released in the core and shell. However, an additional increase in the number phasic release events occurred only within the NAc shell, and this increase was eliminated by inactivation of midbrain dopaminergic neurons. This represents the first evidence that cocaine directly increases the frequency of dopamine release events and reveals that this is responsible for preferentially increased dopamine transmission within the NAc shell after cocaine administration. Additionally, cocaine administration resulted in a synergistic increase in dopamine concentration, and subregion differences were abolished when cocaine was administered in the absence of autoregulation. Together, these results demonstrate that cocaine administration results in a temporally and regionally specific increase in phasic dopamine release that is significantly regulated by dopamine autoreceptors. PMID:18753384

  1. The Relationship between Reversed Masked Priming and the Tri-Phasic Pattern of the Lateralised Readiness Potential

    PubMed Central

    Seiss, Ellen; Klippel, Marie; Hope, Christopher; Boy, Frederic; Sumner, Petroc

    2014-01-01

    One of the potential explanations for negative compatibility effects (NCE) in subliminal motor priming tasks has been perceptual prime-target interactions. Here, we investigate whether the characteristic tri-phasic LRP pattern associated with the NCE is caused by these prime-target interactions. We found that both the prime-related phase and the critical reversal phase remain present even on trials where the target is omitted, confirming they are elicited by the prime and mask, not by prime-target interactions. We also report that shape and size of the reversal phase are associated with response speed, consistent with a causal role for the reversal for the subsequent response latency. Additionally, we analysed sequential modulation of the NCE by previous conflicting events, even though such conflict is subliminal. In accordance with previous literature, this modulation is small but significant. PMID:24728088

  2. [The dynamic of annual modification of phasic structure of cardiac cycle in children of junior school age].

    PubMed

    Iashchenko, A H; Vdovychenko, O M

    2013-01-01

    By using of the method of tetrapolar impedance rheopletysmography we studied the phasic structure of cardiac cycle in children of junior school age. We have shown that a decrease of cardiac cycle duration in children is due to a decrease of the common diastole duration, the mean fraction of which in children of six years is 48.58% from the cardiac cycle duration. With age the duration of cardiac cycle increases. In 12 y.o. children this parameter is significantly higher (0.702 +/- 0.020s) that that observed in 6 y.o. children (0.636 +/- 0.017s). The shortest duration of cardiac cycle is detected in 10 y.o. children (0.617 +/- 0.018 s). PMID:23957170

  3. 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

  4. 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

  5. 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

  6. Phasic Activation of Individual Neurons in the Locus Ceruleus/Subceruleus Complex of Monkeys Reflects Rewarded Decisions to Go But Not Stop

    PubMed Central

    Kalwani, Rishi M.; Joshi, Siddhartha

    2014-01-01

    Neurons in the brainstem nucleus locus ceruleus (LC) often exhibit phasic activation in the context of simple sensory-motor tasks. The functional role of this activation, which leads to the release of norepinephrine throughout the brain, is not yet understood in part because the conditions under which it occurs remain in question. Early studies focused on the relationship of LC phasic activation to salient sensory events, whereas more recent work has emphasized its timing relative to goal-directed behavioral responses, possibly representing the end of a sensory-motor decision process. To better understand the relationship between LC phasic activation and sensory, motor, and decision processing, we recorded spiking activity of neurons in the LC+ (LC and the adjacent, norepinephrine-containing subceruleus nucleus) of monkeys performing a countermanding task. The task required the monkeys to occasionally withhold planned, saccadic eye movements to a visual target. We found that many well isolated LC+ units responded to both the onset of the visual cue instructing the monkey to initiate the saccade and again after saccade onset, even when it was initiated erroneously in the presence of a stop signal. Many of these neurons did not respond to saccades made outside of the task context. In contrast, neither the appearance of the stop signal nor the successful withholding of the saccade elicited an LC+ response. Therefore, LC+ phasic activation encodes sensory and motor events related to decisions to execute, but not withhold, movements, implying a functional role in goal-directed actions, but not necessarily more covert forms of processing. PMID:25297093

  7. 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.

  8. 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

  9. 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.

  10. The timing of phasic transmitter release is Ca2+-dependent and lacks a direct influence of presynaptic membrane potential

    PubMed Central

    Felmy, Felix; Neher, Erwin; Schneggenburger, Ralf

    2003-01-01

    Ca2+ influx through voltage-gated Ca2+ channels and the resulting elevation of intracellular Ca2+ concentration, [Ca2+]i, triggers transmitter release in nerve terminals. However, it is controversial whether in addition to the opening of Ca2+ channels, membrane potential directly affects transmitter release. Here, we assayed the influence of membrane potential on transmitter release at the calyx of Held nerve terminals. Transmitter release was evoked by presynaptic Ca2+ uncaging, or by presynaptic Ca2+ uncaging paired with presynaptic voltage-clamp depolarizations to +80 mV, under pharmacological block of voltage-gated Ca2+ channels. Such a change in membrane potential did not alter the Ca2+ dependence of transmitter release rates or synaptic delays. We also found, by varying the amount of Ca2+ influx during Ca2+ tail-currents, that the time course of phasic transmitter release is not invariant to changes in release probability. Rather, the time difference between peak Ca2+ current and peak transmitter release became progressively shorter with increasing Ca2+ current amplitude. When this time difference was plotted as a function of the estimated local [Ca2+]i at the sites of vesicle fusion, a slope of ≈100 μs per 10 μM [Ca2+]i was found, in reasonable agreement with a model of cooperative Ca2+ binding and vesicle fusion. Thus, the amplitude and time course of the [Ca2+]i signal at the sites of vesicle fusion controls the timing and the amount of transmitter release, both under conditions of brief periods of Ca2+ influx, as well as during step-like elevations of [Ca2+]i produced by Ca2+ uncaging. PMID:14630950

  11. The timing of phasic transmitter release is Ca2+-dependent and lacks a direct influence of presynaptic membrane potential.

    PubMed

    Felmy, Felix; Neher, Erwin; Schneggenburger, Ralf

    2003-12-01

    Ca2+ influx through voltage-gated Ca2+ channels and the resulting elevation of intracellular Ca2+ concentration, [Ca2+]i, triggers transmitter release in nerve terminals. However, it is controversial whether in addition to the opening of Ca2+ channels, membrane potential directly affects transmitter release. Here, we assayed the influence of membrane potential on transmitter release at the calyx of Held nerve terminals. Transmitter release was evoked by presynaptic Ca2+ uncaging, or by presynaptic Ca2+ uncaging paired with presynaptic voltage-clamp depolarizations to +80 mV, under pharmacological block of voltage-gated Ca2+ channels. Such a change in membrane potential did not alter the Ca2+ dependence of transmitter release rates or synaptic delays. We also found, by varying the amount of Ca2+ influx during Ca2+ tail-currents, that the time course of phasic transmitter release is not invariant to changes in release probability. Rather, the time difference between peak Ca2+ current and peak transmitter release became progressively shorter with increasing Ca2+ current amplitude. When this time difference was plotted as a function of the estimated local [Ca2+]i at the sites of vesicle fusion, a slope of approximately 100 micros per 10 microM [Ca2+]i was found, in reasonable agreement with a model of cooperative Ca2+ binding and vesicle fusion. Thus, the amplitude and time course of the [Ca2+]i signal at the sites of vesicle fusion controls the timing and the amount of transmitter release, both under conditions of brief periods of Ca2+ influx, as well as during step-like elevations of [Ca2+]i produced by Ca2+ uncaging. PMID:14630950

  12. 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

  13. 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

  14. 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. PMID:26313710

  15. Binding loci of RelA-containing nuclear factor-kappaB dimers in promoter regions of PHM1-31 myometrial smooth muscle cells.

    PubMed

    Cookson, Victoria J; Waite, Sarah L; Heath, Paul R; Hurd, Paul J; Gandhi, Saurabh V; Chapman, Neil R

    2015-11-01

    Human parturition is associated with many pro-inflammatory mediators which are regulated by the nuclear factor-kappaB (NF-κB) family of transcription factors. In the present study, we employed a ChIP-on-chip approach to define genomic loci within chromatin of PHM1-31 myometrial cells that were occupied by RelA-containing NF-κB dimers in response to a TNF stimulation of 1 h. In TNF-stimulated PHM1-31 cells, anti-RelA serum enriched 13 300 chromatin regions; importantly, 11 110 regions were also enriched by anti-RelA antibodies in the absence of TNF. DNA sequences in these regions, from both unstimulated or TNF-stimulated PHM1-31 cultures, were associated with genic regions including IκBα, COX-2, IL6RN, Jun and KCNMB3. TNF-induced binding events at a consensus κB site numbered 1667; these were represented by 112 different instances of the consensus κB motif. Of the 1667 consensus κB motif occurrences, 770 (46.2%) were identified within intronic regions. In unstimulated PHM1-31 cells, anti-RelA-serum-enriched regions were associated with sequences corresponding to open reading frames of ion channel subunit genes including CACNB3 and KCNB1. Moreover, in unstimulated cells, the consensus κB site was identified 2116 times, being defined by 103 different sequence instances of this motif. Of these 2116 consensus κB motifs, 1089 (51.5%) were identified within intronic regions. Parallel expression array analyses in PHM1-31 cultures demonstrated that TNF stimulated a >2-fold induction in 51 genes and a fold repression of >1.5 in 18 others. We identified 14 anti-RelA-serum-enriched genomic regions that correlated with 17 TNF-inducible genes, such as COX2, Egr-1, Jun, IκBα and IL6, as well as five regions associated with TNF-mediated gene repression, including Col1A2. PMID:26405173

  16. 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

  17. Slow noise in the period of a biological oscillator underlies gradual trends and abrupt transitions in phasic relationships in hybrid neural networks.

    PubMed

    Thounaojam, Umeshkanta S; Cui, Jianxia; Norman, Sharon E; Butera, Robert J; Canavier, Carmen C

    2014-05-01

    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

  18. Phasic Dopamine Release in the Nucleus Accumbens in Response to Pro-Social 50 kHz Ultrasonic Vocalizations in Rats

    PubMed Central

    Tose, Amanda; Wanat, Matthew J.; Hart, Andrew S.; Hollon, Nick G.; Phillips, Paul E.M.; Schwarting, Rainer K.W.

    2014-01-01

    Rats emit ultrasonic vocalizations (USVs) that are thought to serve as situation-dependent affective signals and accomplish important communicative functions. In appetitive situations, rats produce 50 kHz USVs, whereas 22 kHz USVs occur in aversive situations. Reception of 50 kHz USVs induces social approach behavior, while 22 kHz USVs lead to freezing behavior. These opposite behavioral responses are paralleled by distinct brain activation patterns, with 50 kHz USVs, but not 22 kHz USVs, activating neurons in the nucleus accumbens (NAcc). The NAcc mediates appetitive behavior and is critically modulated by dopaminergic afferents that are known to encode the value of reward. Therefore, we hypothesized that 50 kHz USVs, but not 22 kHz USVs, elicit NAcc dopamine release. While recording dopamine signaling with fast-scan cyclic voltammetry, freely moving rats were exposed to playback of four acoustic stimuli via an ultrasonic speaker in random order: (1) 50 kHz USVs, (2) 22 kHz USVs, (3) time- and amplitude-matched white noise, and (4) background noise. Only presentation of 50 kHz USVs induced phasic dopamine release and elicited approach behavior toward the speaker. Both of these effects, neurochemical and behavioral, were most pronounced during initial playback, but then declined rapidly with subsequent presentations, indicating a close temporal relationship between the two measures. Moreover, the magnitudes of these effects during initial playback were significantly correlated. Collectively, our findings show that NAcc dopamine release encodes pro-social 50 kHz USVs, but not alarming 22 kHz USVs. Thus, our results support the hypothesis that these call types are processed in distinct neuroanatomical regions and establish a functional link between pro-social communicative signals and reward-related neurotransmission. PMID:25100595

  19. GPR142 Agonists Stimulate Glucose-Dependent Insulin Secretion via Gq-Dependent Signaling

    PubMed Central

    Wang, Jingru; Carrillo, Juan J.; Lin, Hua V.

    2016-01-01

    GPR142 is an islet-enriched G protein-coupled receptor that has been investigated as a novel therapeutic target for the treatment of type 2 diabetes by virtue of its insulin secretagogue activity. However, the signaling pathways downstream of GPR142 and whether its stimulation of insulin release is glucose-dependent remain poorly characterized. In this study, we show that both native and synthetic GPR142 agonists can activate Gq as well as Gi signaling when GPR142 is recombinantly expressed in HEK293 cells. However, in primary pancreatic islets, a native cellular system, the insulin secretagogue activity of GPR142 agonists only requires Gq activation. In addition, our results show that stimulation of insulin secretion by GPR142 in pancreatic islets is strictly glucose-dependent. PMID:27104960

  20. 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

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

    PubMed

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

    2011-11-18

    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-treatment with anti-MMP1 antibody. This study contributes to understanding mechanisms underlying muscarinic receptor agonist-induced promotion of colon cancer and, more importantly, indicates that blocking MMP1 expression and activation has therapeutic promise to stop or retard colon cancer invasion and dissemination. PMID:22027145

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

    PubMed Central

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

    2015-01-01

    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. PMID:25668514

  3. 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.

  4. 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

  5. Comparison of organ-specific-radiation dose levels between 70 kVp perfusion CT and standard tri-phasic liver CT in patients with hepatocellular carcinoma using a Monte-Carlo-Simulation-based analysis platform

    PubMed Central

    Gawlitza, J.; Haubenreisser, H.; Meyer, M.; Hagelstein, C.; Sudarski, S.; Schoenberg, S.O.; Henzler, T.

    2016-01-01

    Purpose The aim of this study was to systematically compare organ-specific-radiation dose levels between a radiation dose optimized perfusion CT (dVPCT) protocol of the liver and a tri-phasic standard CT protocol of the liver using a Monte-Carlo-Simulation-based analysis platform. Methods and materials The complete CT data of 52 patients (41 males; mean age 65 ± 12) with suspected HCC that underwent dVPCT examinations on a 3rd generation dual-source CT (Somatom Force, Siemens) with a dose optimized tube voltage of 70 kVp or 80 kVp were exported to an analysis platform (Radimetrics, Bayer). The dVPCT studies were matched with a reference group of 50 patients (35 males; mean age 65 ± 14) that underwent standard tri-phasic CT (sCT) examinations of the liver with 130 kVp using the calculated water-equivalent-diameter of the patients. The analysis platform was used for the calculation of the organ-specific effective dose (ED) as well as global radiation-dose parameters (ICRP103). Results The organ-specific ED of the dVPCT protocol was statistically significantly lower when compared to the sCT in 14 of 21, and noninferior in a total of 18 of 21 examined items (all p < 0.05). The EDs of the dVPCT examinations were especially in the dose sensitive organs such as the red marrow (17.3 mSv vs 24.6 mSv, p = < 0.0001) and the liver (33.3 mSv vs 46.9 mSv, p = 0.0003) lower when compared to the sCT. Conclusion Our results suggest that dVPCT performed at 70 or 80 kVp compares favorably to sCT performed with 130 kVp with regard to effective organ dose levels, especially in dose sensitive organs, while providing additional functional information which is of paramount importance in patients undergoing novel targeted therapies. PMID:27200404

  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. Excitation-induced cell damage and beta2-adrenoceptor agonist stimulated force recovery in rat skeletal muscle.

    PubMed

    Mikkelsen, Ulla Ramer; Gissel, Hanne; Fredsted, Anne; Clausen, Torben

    2006-02-01

    Intensive exercise leads to a loss of force, which may be long lasting and associated with muscle cell damage. To simulate this impairment and to develop means of compensating the loss of force, extensor digitorum longus muscles from 4-wk-old rats were fatigued using intermittent 40-Hz stimulation (10 s on, 30 s off). After stimulation, force recovery, cell membrane leakage, and membrane potential were followed for 240 min. The 30-60 min of stimulation reduced tetanic force to approximately 10% of the prefatigue level, followed by a spontaneous recovery to approximately 20% in 120-240 min. Loss of force was associated with a decrease in K+ content, gain of Na+ and Ca2+ content, leakage of the intracellular enzyme lactic acid dehydrogenase (10-fold increase), and depolarization (13 mV). Stimulation of the Na+-K+ pump with either the beta2-adrenoceptor agonist salbutamol, epinephrine, rat calcitonin gene-related peptide (rCGRP), or dibutyryl cAMP improved force recovery by 40-90%. The beta-blocker propranolol abolished the effect of epinephrine on force recovery but not that of CGRP. Both spontaneous and salbutamol-induced force recovery were prevented by ouabain. The salbutamol-induced force recovery was associated with repolarization of the membrane potential (12 mV) to the level measured in unfatigued muscles. In conclusion, in muscles exposed to fatiguing stimulation leading to a considerable loss of force, cell leakage, and depolarization, stimulation of the Na+-K+ pump induces repolarization and improves force recovery, possibly due to the electrogenic action of the Na+-K+ pump. This mechanism may be important for the restoration of muscle function after intense exercise. PMID:16210418

  8. Metabolic Syndrome Abolishes Glucagon-Like Peptide 1 Receptor Agonist Stimulation of SERCA in Coronary Smooth Muscle.

    PubMed

    Dineen, Stacey L; McKenney, Mikaela L; Bell, Lauren N; Fullenkamp, Allison M; Schultz, Kyle A; Alloosh, Mouhamad; Chalasani, Naga; Sturek, Michael

    2015-09-01

    Metabolic syndrome (MetS) doubles the risk of adverse cardiovascular events. Glucagon-like peptide 1 (GLP-1) receptor agonists induce weight loss, increase insulin secretion, and improve glucose tolerance. Studies in healthy animals suggest cardioprotective properties of GLP-1 receptor agonists, perhaps partially mediated by improved sarco-endoplasmic reticulum Ca(2+) ATPase (SERCA) activity. We examined the acute effect of GLP-1 receptor agonists on coronary smooth muscle cells (CSM) enzymatically isolated from lean, healthy Ossabaw miniature swine. Intracellular Ca(2+) handling was interrogated with fura-2. The GLP-1 receptor agonist exenatide activated SERCA but did not alter other Ca(2+) transporters. Further, we tested the hypothesis that chronic, in vivo treatment with GLP-1 receptor agonist AC3174 would attenuate coronary artery disease (CAD) in swine with MetS. MetS was induced in 20 swine by 6 months' feeding of a hypercaloric, atherogenic diet. Swine were then randomized (n = 10/group) into placebo or AC3174 treatment groups and continued the diet for an additional 6 months. AC3174 treatment attenuated weight gain, increased insulin secretion, and improved glucose tolerance. Intravascular ultrasound and histology showed no effect of AC3174 on CAD. MetS abolished SERCA activation by GLP-1 receptor agonists. We conclude that MetS confers vascular resistance to GLP-1 receptor agonists, partially through impaired cellular signaling steps involving SERCA. PMID:25845661

  9. Local and cellular Ca2+ transients in smooth muscle of pressurized rat resistance arteries during myogenic and agonist stimulation.

    PubMed

    Miriel, V A; Mauban, J R; Blaustein, M P; Wier, W G

    1999-08-01

    1. Confocal laser scanning microscopy was used to visualize Ca2+ transients in the vascular smooth muscle cells (VSMC) of intact, pressurized rat mesenteric resistance arteries loaded with fluorescent calcium indicators. Vasoconstriction was assessed by measuring inner arterial diameter. All arteries were studied at 70 mmHg intralumenal pressure and 37 C. 2. In the control condition of myogenic tone the arteries were constricted to 62 % (n = 10) of their passive diameter (p.d.). The [Ca2+]i in most VSMC of these arteries was constant over time. In a small percentage (< 10 %) of cells in each artery, [Ca2+]i oscillated regularly. Local calcium transients (Ca2+ sparks) were observed in five arteries studied with confocal linescan imaging. 3. Activation of alpha-adrenoceptors by phenylephrine (PE, 1.0 microM) induced further vasoconstriction of pressurized arteries (to 27 % of p.d.). In this condition, [Ca2+]i oscillations were prominent in a large percentage (83 %) of the VSMC. The Ca2+ oscillations ranged in frequency from 4 to 22 min-1, and were usually asynchronous between cells. 4. High [KCl]o (65 mM) induced nearly comparable vasoconstriction to PE (37 % of p.d.) but [Ca2+]i oscillated in only about 13 % of cells in each artery. 5. Block of L-type Ca2+ channels (with nifedipine) in arteries activated by PE caused nearly full vasodilatation, but did not abolish the Ca2+ oscillations. Subsequent block of the sarcoplasmic reticulum Ca2+ pump (with cyclopiazonic acid) abolished Ca2+ oscillations in all cells. 6. We conclude that Ca2+ entering VSMC via L-type Ca2+ channels has an obligatory role in force development, both in myogenic tone and during alpha1-adrenoceptor activation. The oscillatory pattern of [Ca2+]i that persists in the absence of Ca2+ entry via L-type Ca2+ channels is ineffective in activating contraction. PMID:10420017

  10. G/sub o/ protein of fat cells: role in hormonal regulation of agonist-stimulated phosphatidyl inositol breakdown

    SciTech Connect

    Rapiejko, P.J.; Northup, J.K.; Malbon, C.C.

    1986-05-01

    Incubating rat fat cell membranes in the presence of (/sup 32/P)NAD/sup +/ and pertussis toxin (PT) results in the ADP-ribosylation of two peptides (M/sub r/ = 41,000 and 40,000). The 41,000-M/sub r/ peptide is the inhibitory G-protein of adenylate cyclase (G/sub i/). The 40,000-M/sub r/ peptide radiolabeled in the presence of (/sup 32/P)NAD/sup +/ and PT has been purified from rabbit heart and bovine brain, but has not been identified uniformly in membranes of fat cells. Two rabbit polyclonal antisera raised against the alpha-subunit of bovine brain G/sub o/ were used to probe the nature of the 40,000-M/sub r/ peptide in rat fat cell membranes that had been separated by gel electrophoresis in the presence of sodium dodecyl sulfate and transferred electrophoretically to nitrocellulose. Both antisera specific for the alpha-subunit of G/sub o/ recognized the M/sub r/ = 40,000 peptide of fat cells that is ADP-ribosylated in the presence of PT. PT treatment of rat fat cells blocks epinephrine-stimulated inositol 1,4,5 trisphosphate (IP/sub 3/) generation. The inhibition of IP/sub 3/ generation by PT suggests a role for either G/sub i/ or G/sub o/ in receptor-mediated phosphatidyl inositol breakdown in the rat fat cell.

  11. Regulation of β1- and β3-adrenergic agonist-stimulated lipolytic response in hyperthyroid and hypothyroid rat white adipocytes

    PubMed Central

    Germack, Renée; Starzec, Anna; Perret, Gérard Y

    2000-01-01

    This study examined the effects of thyroid status on the lipolytic responses of rat white adipocytes to β-adrenoceptor (β-AR) stimulation. The β1- and β3-AR mRNAs and proteins were measured by Northern and saturation analyses, respectively. Glycerol production and adenyl cyclase (AC) activity induced by various non-selective and selective β1/β3-AR agonists and drugs which act distal to the receptor in the signalling cascade were measured in cells from untreated, tri-iodothyronine (T3)-treated and thyroidectomized rats. The β3-AR density was enhanced (72%) by T3-treatment and reduced (50%) by introduction of a hypothyroid state while β1-AR number remained unaffected. The β1- and β3-AR density was correlated with the specific mRNA level in all thyroid status. The lipolytic responses to isoprenaline, noradrenaline (β1/β3/β3-AR agonists) and BRL 37344 (β3-AR agonist) were potentiated by 48, 58 and 48%, respectively in hyperthyroidism and reduced by about 80% in hypothyroidism. T3-treatment increased the maximal lipolytic response to the partial β3-AR (CGP 12177) and β1-AR (xamoterol) agonists by 234 and 260%, respectively, increasing their efficacy (intrinsic activity: 0.95 versus 0.43 and 1.02 versus 0.42). The maximal AC response to these agonists was increased by 84 and 58%, respectively, without changing their efficacy. In the hypothyroid state, the maximal lipolytic and AC responses were decreased with CGP (0.17±0.03 versus 0.41±0.08 μmol glycerol/106 adipocytes; 0.048±0.005 versus 0.114±0.006 pmol cyclic AMP min−1 mg−1) but not changed with xamoterol. The changes in lipolytic responses to postreceptor-acting agents (forskolin, enprofylline and dibutenyl cyclic AMP, (Bu)2cAMP) suggest the modifications on receptor coupling and phosphodiesterase levels in both thyroid states. Thyroid status affects lipolysis by modifying β3-AR density and postreceptor events without changes in the β1-AR functionality. PMID:10711342

  12. 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

  13. Estrogen Receptor β-Selective Agonists Stimulate Calcium Oscillations in Human and Mouse Embryonic Stem Cell-Derived Neurons

    PubMed Central

    Zhang, Lili; Blackman, Brigitte E.; Schonemann, Marcus D.; Zogovic-Kapsalis, Tatjana; Pan, Xiaoyu; Tagliaferri, Mary; Harris, Heather A.; Cohen, Isaac; Reijo Pera, Renee A.; Mellon, Synthia H.; Weiner, Richard I.; Leitman, Dale C.

    2010-01-01

    Estrogens are used extensively to treat hot flashes in menopausal women. Some of the beneficial effects of estrogens in hormone therapy on the brain might be due to nongenomic effects in neurons such as the rapid stimulation of calcium oscillations. Most studies have examined the nongenomic effects of estrogen receptors (ER) in primary neurons or brain slices from the rodent brain. However, these cells can not be maintained continuously in culture because neurons are post-mitotic. Neurons derived from embryonic stem cells could be a potential continuous, cell-based model to study nongenomic actions of estrogens in neurons if they are responsive to estrogens after differentiation. In this study ER-subtype specific estrogens were used to examine the role of ERα and ERβ on calcium oscillations in neurons derived from human (hES) and mouse embryonic stem cells. Unlike the undifferentiated hES cells the differentiated cells expressed neuronal markers, ERβ, but not ERα. The non-selective ER agonist 17β-estradiol (E2) rapidly increased [Ca2+]i oscillations and synchronizations within a few minutes. No change in calcium oscillations was observed with the selective ERα agonist 4,4′,4″-(4-Propyl-[1H]-pyrazole-1,3,5-triyl)trisphenol (PPT). In contrast, the selective ERβ agonists, 2,3-bis(4-Hydroxyphenyl)-propionitrile (DPN), MF101, and 2-(3-fluoro-4-hydroxyphenyl)-7-vinyl-1,3 benzoxazol-5-ol (ERB-041; WAY-202041) stimulated calcium oscillations similar to E2. The ERβ agonists also increased calcium oscillations and phosphorylated PKC, AKT and ERK1/2 in neurons derived from mouse ES cells, which was inhibited by nifedipine demonstrating that ERβ activates L-type voltage gated calcium channels to regulate neuronal activity. Our results demonstrate that ERβ signaling regulates nongenomic pathways in neurons derived from ES cells, and suggest that these cells might be useful to study the nongenomic mechanisms of estrogenic compounds. PMID:20668547

  14. Responses of motor units during the hind limb flexion withdrawal reflex evoked by noxious skin heating: phasic and prolonged suppression by midbrain stimulation and comparison with simultaneously recorded dorsal horn units.

    PubMed

    Carstens, E; Campell, I G

    1992-02-01

    In rats anesthetized with sodium pentobarbital, we quantitatively analyzed descending modulation from the midbrain of a nociceptive flexion withdrawal reflex and responses of associated spinal neurons. We monitored the isometric force of hind limb withdrawal elicited by noxious heat stimuli (42-54 degrees C, 10 sec) on the hind paw. In one series of experiments, single-fiber EMG electrodes recorded responses of single muscle fibers (i.e., motor units) in biceps femoris during the hind limb withdrawal, without and during electrical stimulation in the midbrain periaqueductal gray (PAG) or lateral midbrain reticular formation (LRF). In a second series, responses of single lumbar dorsal horn neurons were also recorded simultaneously. Withdrawal force and associated motor unit responses were suppressed for prolonged periods (4 to greater than 60 min) following the initial episode of PAG or LRF stimulation in 40% of the rats, while they were suppressed phasically (i.e., only during brain stimulation) in the remainder. Motor unit responses increased in a graded fashion with increasing skin stimulus temperature from threshold (45 degrees C) to 54 degrees C. During PAG stimulation, the slope of the rate coding function was reduced with no change in threshold temperature. During LRF stimulation the rate coding function was shifted toward higher temperatures with increased threshold (47 degrees C). In 14 experiments 43 paired recordings were made from a dorsal horn and a motor unit during hind limb withdrawals. Mean latency to onset and peak of the heat-evoked response was shorter for dorsal horn compared to motor units. In 6/14 rats withdrawal force and motor unit responses were significantly suppressed for more than 8 min following mechanical placement of the stimulating electrodes and/or the initial episode of midbrain stimulation, while the simultaneously recorded dorsal horn unit responses remained constant. Following supplemental administration of pentobarbital (10

  15. 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…

  16. Leukotrienes and myometrial activity of the term pregnant uterus.

    PubMed

    Bryman, I; Hammarström, S; Lindblom, B; Norström, A; Wikland, M; Wiqvist, N

    1985-12-01

    Biopsies from different segments of the pregnant human uterus were superfused in organ chambers and contractile activity was registered. Leukotriene C4(LTC4) caused inhibition of spontaneous but not noradrenaline induced contractile activity in strips from the cervix. This effect occurred both in early pregnancy and at term. However, the lower and the upper uterine segment of the term pregnant uterus did not respond to LTC4. The results represent a documentation of the segmental differentiation in the uterine response to eicosanoids. PMID:4089206

  17. Decreased agonist-stimulated mitochondrial ATP production caused by a pathological reduction in endoplasmic reticulum calcium content in human complex I deficiency.

    PubMed

    Visch, Henk-Jan; Koopman, Werner J H; Leusink, Anouk; van Emst-de Vries, Sjenet E; van den Heuvel, Lambertus W P J; Willems, Peter H G M; Smeitink, Jan A M

    2006-01-01

    Although a large number of mutations causing malfunction of complex I (NADH:ubiquinone oxidoreductase) of the OXPHOS system is now known, their cell biological consequences remain obscure. We previously showed that the bradykinin (Bk)-induced increase in mitochondrial [ATP] ([ATP](M)) is significantly reduced in primary skin fibroblasts from a patient with an isolated complex I deficiency. The present work addresses the mechanism(s) underlying this impaired response. Luminometry of fibroblasts from 6 healthy subjects and 14 genetically characterized patients expressing mitochondria targeted luciferase revealed that the Bk-induced increase in [ATP](M) was significantly, but to a variable degree, decreased in 10 patients. The same variation was observed for the increases in mitochondrial [Ca(2+)] ([Ca(2+)](M)), measured with mitochondria targeted aequorin, and cytosolic [Ca(2+)] ([Ca(2+)](C)), measured with fura-2, and for the Ca(2+) content of the endoplasmic reticulum (ER), calculated from the increase in [Ca(2+)](C) evoked by thapsigargin, an inhibitor of the ER Ca(2+) ATPase. Regression analysis revealed that the increase in [ATP](M) was directly proportional to the increases in [Ca(2+)](C) and [Ca(2+)](M) and to the ER Ca(2+) content. Our findings provide evidence that a pathological reduction in ER Ca(2+) content is the direct cause of the impaired Bk-induced increase in [ATP](M) in human complex I deficiency. PMID:16213125

  18. 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. PMID:25632025

  19. 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

  20. Differential induction of nitric oxide, degranulation, and oxidative burst activities in response to microbial agonist stimulation in monocytes and heterophils from young commercial turkeys

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Toll-like receptors (TLRs) recognize microbial pathogens and pathogen associated molecular patterns and trigger inflammatory immune responses to control the infection. Here, we examined functional innate immune responses to Salmonella enteritidis (SE, live or formalin-killed) and various TLR ag...

  1. 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

  2. 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.

  3. Toll‑like receptor 9 agonist stimulation enables osteogenic differentiation without altering the immune status of umbilical cord mesenchymal stem cells.

    PubMed

    Yang, Yongfeng; Wang, Yanwen; Li, Li; Bao, Ji; Chen, Fei; Zhang, Li

    2015-12-01

    Mesenchymal stem cells (MSCs) possess three characteristics critical to tissue regeneration; multipotency, low immunogenicity and an undifferentiated status, providing plasticity. However, increasing evidence has indicated that induction of an immune response in vivo can injure and reject MSC‑based tissues. Toll‑like receptors (TLRs) are a family of pathogen‑associated pattern recognition receptors, which are important in bridging the innate and adaptive immune responses. TLRs have been demonstrated to exhibit important MSC biological regulatory functions in previous studies. To confirm the role of TLR9 in the immune status maintenance of MSCs isolated from umbilical cords, the present study performed assessments to detect agonist effects. Following addition of the TLR9 agonist, CpG, to an umbilical cord mesenchymal stem cell (UCMSC) culture medium, a number of methods were used to detect the changes in the biological function of the UCMSCs. Reverse transcription‑quantitative polymerase chain reaction indicated increased levels of pro‑inflammatory molecules and decreased expression levels of stem cell markers following exposure to the TLR9 agonist. However, flow cytometry revealed that activation of TLR9 had no effect on the proliferation of peripheral blood leukocytes or the expression of surface markers. The present study also identified that CpG‑oligodeoxynucleotide promoted MSC osteogenic differentiation, while inhibiting MSC proliferation and migration. These results indicated that TLRs and their ligands may serve as regulators of MSC proliferation and differentiation, and affect the maintenance of MSC multipotency. PMID:26498600

  4. Optical suppression of drug-evoked phasic dopamine release

    PubMed Central

    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. PMID:25278845

  5. Janus-type bi-phasic functional nanofibers.

    PubMed

    Starr, Justin D; Andrew, Jennifer S

    2013-05-14

    Multiferroic materials hold enormous potential for a variety of applications, including tunable microelectronics and multiphase memories. This paper describes a new type of multiferroic materials with a Janus-type architecture prepared by co-electrospinning sol-gel precursors of barium titanate and cobalt ferrite. PMID:23070402

  6. 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.

  7. REGULATION OF POSTNATAL B-ADRENERGIC RECEPTOR/ADENYLATE CYCLASE DEVELOPMENT BY PRENATAL AGONIST STIMULATION AND STEROIDS: ALTERATIONS IN RAT KIDNEY AND LUNG AFTER EXPOSURE TO TERBUTALINE OR DEXAMETHASONE

    EPA Science Inventory

    Glucocorticoids and adrenergic stimulation are both thought to control the development of adrenergic receptors/responses. n the current study, rats were exposed to dexamethasone or terbutaline during late gestation and the development of B-binding capabilities and adenylate cycla...

  8. 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. PMID:19106171

  9. Human Effector / Initiator Gene Sets That Regulate Myometrial Contractility During Term and Preterm Labor

    PubMed Central

    WEINER, Carl P.; MASON, Clifford W.; DONG, Yafeng; BUHIMSCHI, Irina A.; SWAAN, Peter W.; BUHIMSCHI, Catalin S.

    2010-01-01

    Objective Distinct processes govern transition from quiescence to activation during term (TL) and preterm labor (PTL). We sought gene sets responsible for TL and PTL, along with the effector genes necessary for labor independent of gestation and underlying trigger. Methods Expression was analyzed in term and preterm +/− labor (n =6 subjects/group). Gene sets were generated using logic operations. Results 34 genes were similarly expressed in PTL/TL but absent from nonlabor samples (Effector Set). 49 genes were specific to PTL (Preterm Initiator Set) and 174 to TL (Term Initiator Set). The gene ontogeny processes comprising Term Initiator and Effector Sets were diverse, though inflammation was represented in 4 of the top 10; inflammation dominated the Preterm Initiator Set. Comments TL and PTL differ dramatically in initiator profiles. Though inflammation is part of the Term Initiator and the Effector Sets, it is an overwhelming part of PTL associated with intraamniotic inflammation. PMID:20452493

  10. 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

  11. Towards understanding the myometrial physiome: approaches for the construction of a virtual physiological uterus

    PubMed Central

    Taggart, Michael John; Blanks, Andrew; Kharche, Sanjay; Holden, Arun; Wang, Bin; Zhang, Henggui

    2007-01-01

    Premature labour (PTL) is the single most significant factor contributing to neonatal morbidity in Europe with enormous attendant healthcare and social costs. Consequently, it remains a major challenge to alleviate the cause and impact of this condition. Our ability to improve the diagnosis and treatment of women most at risk of PTL is, however, actually hampered by an incomplete understanding of the ways in which the functions of the uterine myocyte are integrated to effect an appropriate biological response at the multicellular whole organ system. The level of organization required to co-ordinate labouring uterine contractile effort in time and space can be considered immense. There is a multitude of what might be considered mini-systems involved, each with their own regulatory feedback cycles, yet they each, in turn, will influence the behaviour of a related system. These include, but are not exclusive to, gestational-dependent regulation of transcription, translation, post-translational modifications, intracellular signaling dynamics, cell morphology, intercellular communication and tissue level morphology. We propose that in order to comprehend how these mini-systems integrate to facilitate uterine contraction during labour (preterm or term) we must, in concert with biological experimentation, construct detailed mathematical descriptions of our findings. This serves three purposes: firstly, providing a quantitative description of series of complex observations; secondly, proferring a database platform that informs further testable experimentation; thirdly, advancing towards the establishment of a virtual physiological uterus and in silico clinical diagnosis and treatment of PTL. PMID:17570163

  12. 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

  13. Extinction and Reinstatement of Phasic Dopamine Signals in the Nucleus Accumbens Core during Pavlovian Conditioning

    PubMed Central

    Sunsay, Ceyhun; Rebec, George V.

    2014-01-01

    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 (NAc), which plays a key role in reward processing. Following at least 4 daily sessions of 16 tone-food pairings, FSCV was performed while rats received additional tone-food pairings followed by tone alone presentations (i.e., extinction). Acquisition memory was reinstated with non-contingent presentations of reward and then tested with cue presentation. Tone-food pairings produced transient (1–3 s) DA release in response to tone. During extinction, the amplitude of the DA response decreased significantly. Following presentation of two non-contingent food pellets, subsequent tone presentation reinstated the DA signal. Our results support the prediction-error model for appetitive Pavlovian extinction but not for reinstatement. PMID:25111335

  14. Phasic Alertness Can Modulate Executive Control by Enhancing Global Processing of Visual Stimuli

    ERIC Educational Resources Information Center

    Weinbach, Noam; Henik, Avishai

    2011-01-01

    Researchers have suggested that the attention system is composed of several networks that have different functions. One of these networks is responsible for achieving and maintaining an alert state (alerting system), and another for selection and conflict resolution (executive control). There is growing interest in how these attentional networks…

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

    PubMed

    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

  16. 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

  17. The lateral mesopontine tegmentum regulates both tonic and phasic activity of VTA dopamine neurons

    PubMed Central

    Chen, Li

    2013-01-01

    Anatomic studies have demonstrated that the mesolimbic dopamine system receives a substantial afferent input from a variety of regions ranging from the prefrontal cortex through to the brain stem. However, how these afferents regulate dopamine neuron activity is still largely unknown. The mesopontine tegmentum provides a significant input to ventral tegmental area (VTA) dopamine neurons, and it has been demonstrated that discrete subdivisions within this region differentially alter dopamine neuron activity. Thus the laterodorsal tegmental nucleus provides a tonic input essential for maintaining burst firing of dopamine neurons, whereas the pedunculopontine tegmental (PPTg) nucleus regulates a transition from single-spike firing to burst firing. In contrast, the recently identified rostromedial tegmental nucleus provides an inhibitory input to the VTA and decreases spontaneous dopamine neuron activity. Here, we demonstrate that an area adjacent to the PPTg regulates both population activity as well as burst firing of VTA dopamine neurons. Specifically, N-methyl-d-aspartic acid (NMDA) activation of the lateral mesopontine tegmentum produces an increase in the number of spontaneously active dopamine neurons and an increase in the average percentage of burst firing of dopamine neurons. This increase in neuronal activity was correlated with extracellular dopamine efflux in the nucleus accumbens, as measured by in vivo microdialysis. Taken together, we provide further evidence that the mesopontine tegmentum regulates discrete dopamine neuron activity states that are relevant for the understanding of dopamine system function in both normal and disease states. PMID:24004527

  18. 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

  19. Differential activation of myofibrils during fatigue in phasic skeletal muscle cells.

    PubMed

    Garcia, M C; Gonzalez-Serratos, H; Morgan, J P; Perreault, C L; Rozycka, M

    1991-10-01

    In fatigued muscles the T-system is swollen; thus the action potential may fail to travel along the T-system or the T-tubule terminal cisternae signal may fail to bring about TC Ca2+ release. This would lead to a decrease in the number of myofibrils activated and in force development, but if fatigue is the result of a generalized process, all the myofibrils would be affected equally leading to a lower activation of all of them. We have investigated this possibility in isolated twitch muscle fibres by giving them repetitive tetanic stimulations until fatigue developed. The behaviour of myofibrils was followed with cinemicrophotography. Before fatigue, no lack of shortening of myofibrils could be found. During fatigue groups of myofibrils became wavy. When exposed to caffeine, the wavy myofibrils disappeared and tension similar to the control developed. The tension-caffeine concentration relationship was shifted to the left after development of fatigue. In low Na+ solution fatigue developed faster and after reintroducing normal Ringer, tension recovered substantially. K-contractures were smaller during fatigue. These results indicate that in this type of fatigue, a step in the EC coupling chain of events is involved in its development. PMID:1939605

  20. Phasic and Tonic Pain Differentially Impact the Interruptive Function of Pain

    PubMed Central

    Sinke, Christopher; Schmidt, Katharina; Forkmann, Katarina; Bingel, Ulrike

    2015-01-01

    The interruptive effect of painful experimental stimulation on cognitive processes is a well-known phenomenon. This study investigated the influence of pain duration on the negative effects of pain on cognition. Thirty-four healthy volunteers performed a rapid serial visual presentation task (RSVP) in which subjects had to detect (visual detection task) and count the occurrence of a target letter (working memory task) in two separate sessions while being stimulated on the left volar forearm with either short (2 sec) or long (18 sec) painful heat stimuli of equal subjective intensity. The results show that subjects performed significantly worse in the long pain session as indexed by decreased detection and counting performance. Interestingly, this effect on performance was also observed during control trials of the long pain session in which participants did not receive any painful stimulation. Moreover, subjects expected long painful stimulation to have a greater impact on their performance and individual expectation correlated with working memory performance. These findings suggest that not only the length of painful stimulation but also its expected ability to impair cognitive functioning might influence the interruptive function of pain. The exact relevance of expectation for the detrimental effects of pain on cognitive processes needs to be explored in more detail in future studies. PMID:25695254

  1. Exocytosis of ATP From Astrocytes Modulates Phasic and Tonic Inhibition in the Neocortex

    PubMed Central

    Rasooli-Nejad, Seyed; Andrew, Jemma; Haydon, Philip G.; Pankratov, Yuriy

    2014-01-01

    Communication between neuronal and glial cells is important for many brain functions. Astrocytes can modulate synaptic strength via Ca2+-stimulated release of various gliotransmitters, including glutamate and ATP. A physiological role of ATP release from astrocytes was suggested by its contribution to glial Ca2+-waves and purinergic modulation of neuronal activity and sleep homeostasis. The mechanisms underlying release of gliotransmitters remain uncertain, and exocytosis is the most intriguing and debated pathway. We investigated release of ATP from acutely dissociated cortical astrocytes using “sniff-cell” approach and demonstrated that release is vesicular in nature and can be triggered by elevation of intracellular Ca2+ via metabotropic and ionotropic receptors or direct UV-uncaging. The exocytosis of ATP from neocortical astrocytes occurred in the millisecond time scale contrasting with much slower nonvesicular release of gliotransmitters via Best1 and TREK-1 channels, reported recently in hippocampus. Furthermore, we discovered that elevation of cytosolic Ca2+ in cortical astrocytes triggered the release of ATP that directly activated quantal purinergic currents in the pyramidal neurons. The glia-driven burst of purinergic currents in neurons was followed by significant attenuation of both synaptic and tonic inhibition. The Ca2+-entry through the neuronal P2X purinoreceptors led to phosphorylation-dependent down-regulation of GABAA receptors. The negative purinergic modulation of postsynaptic GABA receptors was accompanied by small presynaptic enhancement of GABA release. Glia-driven purinergic modulation of inhibitory transmission was not observed in neurons when astrocytes expressed dn-SNARE to impair exocytosis. The astrocyte-driven purinergic currents and glia-driven modulation of GABA receptors were significantly reduced in the P2X4 KO mice. Our data provide a key evidence to support the physiological importance of exocytosis of ATP from astrocytes in the neocortex. PMID:24409095

  2. 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

  3. 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

  4. 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

  5. Regulation of normal and cystic fibrosis airway surface liquid volume by phasic shear stress.

    PubMed

    Tarran, Robert; Button, Brian; Boucher, Richard C

    2006-01-01

    The physical removal of viruses and bacteria on the mucociliary escalator is an important aspect of the mammalian lung's innate defense mechanism. The volume of airway surface liquid (ASL) present in the respiratory tract is a critical determinant of both mucus hydration and the rate of mucus clearance from the lung. ASL volume is maintained by the predominantly ciliated epithelium via coordinated regulation of (a) absorption, by the epithelial Na+ channel, and (b) secretion, by the Ca2+-activated Cl- channel (CaCC) and CFTR. This review provides an update on our current understanding of how shear stress regulates ASL volume height in normal and cystic fibrosis (CF) airway epithelia through extracellular ATP- and adenosine (ADO)-mediated pathways that modulate ion transport and ASL volume homeostasis. We also discuss (a) how derangement of the ADO-CFTR pathway renders CF airways vulnerable to viral infections that deplete ASL volume and produce mucus stasis, and (b) potential shear stress-dependent therapies for CF. PMID:16460283

  6. Estrous Cycle-Dependent Phasic Changes in the Stoichiometry of Hippocampal Synaptic AMPA Receptors in Rats.

    PubMed

    Tada, Hirobumi; Koide, Mayu; Ara, Wakana; Shibata, Yusuke; Funabashi, Toshiya; Suyama, Kumiko; Goto, Takahisa; Takahashi, Takuya

    2015-01-01

    Cognitive function can be affected by the estrous cycle. However, the effect of the estrous cycle on synaptic functions is poorly understood. Here we show that in female rats, inhibitory-avoidance (IA) task (hippocampus-dependent contextual fear-learning task) drives GluA2-lacking Ca2+-permeable AMPA receptors (CP-AMPARs) into the hippocampal CA3-CA1 synapses during all periods of the estrous cycle except the proestrous period, when estrogen levels are high. In addition, IA task failed to drive CP-AMPARs into the CA3-CA1 synapses of ovariectomized rats only when estrogen was present. Thus, changes in the stoichiometry of AMPA receptors during learning depend on estrogen levels. Furthermore, the induction of long-term potentiation (LTP) after IA task was prevented during the proestrous period, while intact LTP is still expressed after IA task during other period of the estrous cycle. Consistent with this finding, rats conditioned by IA training failed to acquire hippocampus-dependent Y-maze task during the proestrous period. On the other hand, during other estrous period, rats were able to learn Y-maze task after IA conditioning. These results suggest that high estrogen levels prevent the IA learning-induced delivery of CP-AMPARs into hippocampal CA3-CA1 synapses and limit synaptic plasticity after IA task, thus preventing the acquisition of additional learning. PMID:26121335

  7. Effects of Emotion Regulation Difficulties on the Tonic and Phasic Cardiac Autonomic Response

    PubMed Central

    Berna, Guillaume; Ott, Laurent; Nandrino, Jean-Louis

    2014-01-01

    Background Emotion regulation theory aims to explain the interactions between individuals and the environment. In this context, Emotion Regulation Difficulties (ERD) disrupt the physiological component of emotions through the autonomic nervous system and are involved in several psychopathological states. Objective We were interested in comparing the influence of a film-elicited emotion procedure on the autonomic nervous system activity of two groups with different levels of emotion regulation difficulties. Methods A total of 63 women (undergraduate students) ranging from 18 to 27 (20.7±1.99) years old were included. Using the upper and lower quartile of a questionnaire assessing the daily difficulties in regulating emotions, two groups, one with low (LERD) and one with high (HERD) levels of emotion regulation difficulties, were constituted and studied during a film-elicited emotion procedure. Cardiac vagal activity (HF-HRV) was analyzed during three periods: baseline, film-elicited emotion, and recovery. Results The cardiovascular results showed a decrease in HF-HRV from baseline to elicitation for both groups. Then, from elicitation to recovery, HF-HRV increased for the LERD group, whereas a low HF-HRV level persisted for the HERD group. Conclusions The HERD group exhibited inappropriate cardiac vagal recovery after a negative emotion elicitation had ended. Cardiac vagal tone took longer to return to its initial state in the HERD group than in the LERD group. Prolonged cardiac vagal suppression might constitute an early marker of emotion regulation difficulties leading to lower cardiac vagal tone. PMID:25054913

  8. 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...

  9. Is the cold loop hysteroscopic technique a myometrial sparing treatment for placenta accreta residuals in a puerperal uterus?

    PubMed

    Mazzon, Ivano; Favilli, Alessandro; Grasso, Mario; Horvath, Stefano; Gerli, Sandro

    2016-01-01

    Placenta accreta is a life-threatening obstetric pathology characterized by an abnormal invasion of chorionic villi into the uterine wall. The management represents a challenge for the gynecologist, especially in patients desiring to preserve their fertility. Several methods have been proposed to avoid hysterectomy. A case of a hysteroscopic conservative management with the cold loop technique in a puerpera with a large mass of placenta accreta residuals is described. The chorionic tissue was safely detached and it was subsequently removed by an electric cutting loop. Even in the absence of a clear cleavage plane, the thermal damage of surrounding healthy myometrium and dreadful complications as uterine perforation due to the electric cutting loop were avoided. The cold-loop hysteroscopic resection seems to be a safe and effective choice for the treatment of retained placenta accreta in patients desiring to preserve fertility. Moreover, it can also be proposed to patients who need to be treated immediately after delivery. PMID:26212585

  10. 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

  11. Depolarizing pulses to neuromuscular terminals of frogs can elicit graded, phasic transmitter release in the absence of Ca influx.

    PubMed

    Dudel, J

    1990-08-14

    Quantal synaptic currents were recorded by means of a macro-patch-clamp electrode, through which the terminal could be also depolarized by current pulses. The tip of the electrode was perfused rapidly, applying either Ringer's solution or an EGTA-buffered less than 0.1 microM Ca Ringer's. Muscle and nerve outside the electrode were superfused with normal or 10 mM Ca Ringer which served to keep the resting intracellular Ca concentration, Cair, in the terminal below the electrode relatively high. When Ca inflow was prevented by decreasing the Ca concentration to less than 0.1 microM, release was depressed, but still measurable, for low depolarizations, and much less or not at all depressed for large depolarizations to positive membrane potentials. The time course of the depressed release without Ca-inflow was the same as that in the controls with Ca inflow. It appears that the voltage dependent activator proposed in the Ca-voltage theory of release can elicit maximal release in the absence of Ca inflow, provided Cair is sufficiently high. The voltage dependencies of this activator as well as that of Ca inflow can be estimated from the results. PMID:1979669

  12. 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

  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. /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.

  15. NO-induced relaxation of labouring and non-labouring human myometrium is not mediated by cyclic GMP.

    PubMed

    Buxton, I L; Kaiser, R A; Malmquist, N A; Tichenor, S

    2001-09-01

    1. In myometrial strips from near-term non-labouring human uterus, addition of oxytocin (OT) evoked dose-dependent (10 - 3000 nM) phasic contractions that were antagonized by atosiban (1 microM) and relaxed by addition of the nitric oxide donor S-nitroso L-cysteine (Cys-NO). In near-term labouring myometrium, however, addition of OT was ineffective at raising additional tone. 2. In both labouring and non-labouring tissue, Cys-NO mediated relaxation of spontaneous or OT-induced contractions (IC(50)=1 microM) was unaffected by prior addition of the guanylyl cyclase (GC) inhibitors ODQ (1H-[1,2,4]oxadiazolo[4,3,-alpha]quinoxalin-1-one; 1 microM), or methylene blue (MB; 10 microM). 3. Elevation of intracellular cyclic GMP accompanying 30 microM Cys-NO addition in non-labouring tissue (7.5 fold) or in labouring tissues (2.5 fold) was completely blocked in tissues that had been pre-treated with ODQ or MB. 4. Charybdotoxin (ChTx), iberiotoxin (IbTx) and kaliotoxin (KalTx) all shifted the Cys-NO inhibition curve to the right and reduced the degree of relaxation produced by maximal Cys-NO treatment (100 microM in non-labouring tissue; in labouring tissue, KalTx prevented Cys-NO mediated relaxation in both stimulated and unstimulated tissue. 5. Addition of the NO-donor S-nitroso N-acetyl penicillamine (SNAP) produced a dose-dependent relaxation of pregnant myometrium while 3-morpholinosyndonimine (SIN-1) did not. The failure of SIN-1 to relax OT-induced contractions was not due to a failure of the donor to stimulate myometrial GC. 6. We demonstrate that despite the ability of NO to stimulate myometrial GC in pregnant uterine muscle, relaxations are independent of cyclic GMP action. Effects of K(+)-channel inhibitors suggests that NO-induced relaxation in human uterine smooth muscle may be subserved by direct or indirect activation of one or more calcium-activated K(+)-channels. PMID:11522613

  16. 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

  17. Differential effects of rapamycin treatment on tonic and phasic GABAergic inhibition in dentate granule cells after focal brain injury in mice.

    PubMed

    Butler, Corwin R; Boychuk, Jeffery A; Smith, Bret N

    2016-06-01

    The cascade of events leading to post-traumatic epilepsy (PTE) after traumatic brain injury (TBI) remains unclear. Altered inhibition in the hippocampal formation and dentate gyrus is a hallmark of several neurological disorders, including TBI and PTE. Inhibitory synaptic signaling in the hippocampus is predominately driven by γ-aminobutyric acid (GABA) neurotransmission, and is prominently mediated by postsynaptic type A GABA receptors (GABAAR's). Subsets of these receptors involved in tonic inhibition of neuronal membranes serve a fundamental role in maintenance of inhibitory state, and GABAAR-mediated tonic inhibition is altered functionally in animal models of both TBI and epilepsy. In this study, we assessed the effect of mTOR inhibition on hippocampal hilar inhibitory interneuron loss and synaptic and tonic GABAergic inhibition of dentate gyrus granule cells (DGCs) after controlled cortical impact (CCI) to determine if mTOR activation after TBI modulates GABAAR function. Hilar inhibitory interneuron density was significantly reduced 72h after CCI injury in the dorsal two-thirds of the hemisphere ipsilateral to injury compared with the contralateral hemisphere and sham controls. Rapamycin treatment did not alter this reduction in cell density. Synaptic and tonic current measurements made in DGCs at both 1-2 and 8-13weeks post-injury indicated reduced synaptic inhibition and THIP-induced tonic current density in DGCs ipsilateral to CCI injury at both time points post-injury, with no change in resting tonic GABAAR-mediated currents. Rapamycin treatment did not alter the reduced synaptic inhibition observed in ipsilateral DGCs 1-2weeks post-CCI injury, but further reduced synaptic inhibition of ipsilateral DGCs at 8-13weeks post-injury. The reduction in THIP-induced tonic current after injury, however, was prevented by rapamycin treatment at both time points. Rapamycin treatment thus differentially modifies CCI-induced changes in synaptic and tonic GABAAR-mediated currents in DGCs. PMID:27018320

  18. A multi-phasic approach reveals that apple replant disease is caused by multiple biological agents, with some agents acting synergistically

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Apple replant disease (ARD) has been reported from all major fruit-growing regions of the world, and is often caused by a consortium of biological agents. The aim of this study was to investigate the etiology of ARD in South Africa in six orchard soils, using a multiphasic approach under glasshouse ...

  19. 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. PMID:26526454

  20. 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

  1. The effect of stimulus significance on relatively sustained (tonic-like) and relatively transient (phasic-like) aspects of electrodermal, heart rate, and eyeblink response.

    PubMed

    Bernstein, A S; Taylor, K W; Weinstein, E; Riedel, J

    1985-11-01

    To examine the influence of stimulus significance on more sustained as well as transient aspects of electrodermal, cardiac (HR), and eyeblink response, a 21-sec tone was sounded in one ear or the other. A click occurred during many tones, and a light followed offset by 9 sec. Four groups were studied: one pressed a pedal immediately on hearing any click; another only on click during tone in a specified ear; a third also responded only to the specified ear, but withheld press until the light; a fourth listened without any response. Results confirmed the important role of stimulus significance in each system whether between- or within-subject comparisons were made. Sustained responses were seen only when a significant signal was sought, involving in each case sustained HR deceleration, slowed blink rate, and heightened electrodermal level. Transient response to click and light also appeared only when there were significant signals. Response to tone-onset gave more ambiguous results. ANOVAs of response magnitude suggested that onset of nonsignificant tones might have elicited ORs, while binomial tests indicated these were not elicited with better than random frequency anywhere but on those trials occurring more frequently at the experiment's onset. Interpretations consistent with both the significance hypothesis and with a distinction between automatic and voluntary ORs can be made only here. Motor response had no effect on electrodermal or eyeblink response, and on HR was associated only with increased acceleration 1-2 sec after pedal-press. Studies using small motor responses to establish stimulus significance are therefore not likely to be substantially biased by the response itself. PMID:4084626

  2. Morning nutrition and executive function processes in preadolescents: gender variations in phasic modulation of frontal eeg theta activity during a go/ no-go task

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Frontal EEG theta activity has been related to executive functions (i.e., goal-directed behavior such as inhibition and flexibility of action). We studied the effects of morning nutritional status on frontal theta-executive function relationships using stimulus-locked responses [event-related increa...

  3. Phasic alterations in dopamine and serotonin release in striatum and prefrontal cortex in response to cocaine predictive cues in behaving rhesus macaques.

    PubMed

    Bradberry, Charles W; Rubino, Susan R

    2004-04-01

    The ability of environmental cues associated with cocaine availability to cause relapse may result from conditioned activation of dopamine (DA) release. We examined this hypothesis in macaque monkeys by conducting microdialysis studies in animals during exposure to a cocaine predictive compound cue. In addition to studying DA release in mesolimbic and sensorimotor striatum, both DA and serotonin levels were determined in the prefrontal cortex (medial orbitofrontal and anterior cingulate). The compound cue employed visual, auditory, and olfactory components, and was salient to the animals as demonstrated by anticipatory lever pressing in the absence of cocaine. During a 10-min period of exposure prior to cocaine availability, there was no significant increase in striatal or cortical DA. The addition of a DA uptake inhibitor to the striatal perfusate to reduce the potential interference of neuronal uptake did not alter the results. In contrast to the lack of any change in striatal DA, a significant decrease in extracellular serotonin in the prefrontal cortex during the 10 min of cue exposure was observed. PMID:14747825

  4. Human chorionic gonadotropin: Different glycoforms and biological activity depending on its source of production.

    PubMed

    Fournier, Thierry

    2016-06-01

    Human chorionic gonadotropin (hCG) is the first hormonal message from the placenta to the mother. It is detectable in maternal blood two days after implantation and behaves like a super LH agonist stimulating progesterone secretion by the corpus luteum. In addition to maintaining the production of progesterone until the placenta itself produces it, hCG also has a role in myometrial quiescence and local immune tolerance. Specific to humans, hCG is a complex glycoprotein composed of two highly glycosylated subunits. The α-subunit is identical to the pituitary gonadotropin hormones (LH, FSH, TSH), contains two N-glycosylation sites, and is encoded by a single gene (CGA). By contrast, the β-subunits are distinct for each hormones and confer both receptor and biological specificity, although LH and hCG bind to the same receptor (LH/CG-R). The hCG ß-subunit is encoded by a cluster of genes (CGB) and contains two sites of N-glycosylation and four sites of O-glycosylation. The hCG glycosylation state varies with the stage of pregnancy, its source of production and in the pathology. It is well established that hCG is mainly secreted into maternal blood, where it peaks at 8-10weeks of gestation (WG), by the syncytiotrophoblast (ST), which represents the endocrine tissue of the human placenta. The invasive extravillous trophoblast (iEVT) also secretes hCG, and in particular hyperglycosylated forms of hCG (hCG-H) also produced by choriocarcinoma cells. In maternal blood, hCG-H is elevated during early first trimester corresponding to the trophoblastic cell invasion process and then decreases. In addition to its endocrine role, hCG has autocrine and paracrine roles. It promotes formation of the ST and angiogenesis through LH/CG-R but has no effect on trophoblast invasion in vitro. By contrast, hCG-H stimulates trophoblast invasion and angiogenesis by interacting with the TGFß receptor in a LH/CG-R independent signalling pathway. hCG is largely used in antenatal screening

  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. Synchronization of regional contractions of human labor; direct effects of region size and tissue excitability.

    PubMed

    Young, Roger C

    2015-06-25

    The mechanisms used to coordinate organ-level contractions of human labor are not universally accepted. We previously proposed a dual mechanism, where electrical activity coordinates cellular contractions into tissue-level regional contractions, and mechanotransduction synchronizes the regional contractions into organ-level contractions. The simulation of this model successfully recapitulates the phasic pressure rises typical of human labor. In this work we extend the simulation to probe the effects of three critical parameters: electrical coupling (which defines functional regions within the uterine wall), enhancement of contractile responses during action potential bursts (action potential multiplier), and the threshold for mechanical recruitment of regional myometrial contractions (threshold). We test how changing the values of these parameters modulates the ability of the uterus to generate synchronized organ-level contractions. Simulations are performed using Mathematica and a non-classical cellular automaton program we recently published. At least 15 regions are necessary to generate physiologically relevant, synchronized contractions. Organ-level synchronization was improved using higher values for the action potential multiplier. At lower values of the action potential multiplier, synchronized contractions were inhibited when the number of regions was between 32 and 44, suggesting a critical level of electrical coupling is necessary at the onset of labor. Large numbers of low threshold regions resulted in contraction patterns suggestive of hyperstimulation. This work furthers support for the electrical-mechanotransduction mechanism for organ-level synchronization of uterine contractions. The mathematical simulation provides insight regarding how cellular- and tissue-level physiology converge to express synchronized contractions of human labor. PMID:25698238

  7. Effects of calcium entry blockers on tension development and calcium influx in rat uterus.

    PubMed Central

    Granger, S. E.; Hollingsworth, M.; Weston, A. H.

    1986-01-01

    Spontaneous and potassium chloride (KCl)-induced tension development of strips of whole uterus from the day-22 pregnant rat was reduced when the tissues were incubated in a calcium ion (Ca2+)-free medium. Strips of whole uterus, in an initially Ca2+-free medium, responded to the cumulative addition of Ca2+ with graded phasic tension development and associated rapid electrical discharges. The spasms were inhibited by gallopamil (100 nM) and diltiazem (1 microM). Strips of whole uterus in a depolarizing (40 mM K+) medium, which was initially Ca2+-free, responded to the cumulative addition of Ca2+ with graded tonic tension development without associated electrical discharges. These spasms were inhibited by calcium entry blockers with a rank order of potency of nifedipine = gallopamil greater than diltiazem greater than cinnarizine. KCl-induced tension development in endometrium-free uterine strips was antagonized by calcium entry blockers with a rank order of potency of nifedipine greater than gallopamil greater than diltiazem greater than cinnarizine. Ca2+ influx into endometrium-free uterine strips was assessed by means of the 'lanthanum method'. KCl induced a concentration-dependent increase in 45Ca2+ influx which was suppressed or abolished by nifedipine (2.5 nM), gallopamil (100 nM), diltiazem (500 nM) or cinnarizine (5 microM). It is concluded that spontaneous and KCl-induced tension development of rat uterus involves Ca2+ influx from the extracellular medium into the myometrial cell. These results support the hypothesis that nifedipine, gallopamil, diltiazem and cinnarizine inhibit Ca2+- and KCl-induced tension development of rat uterus by reduction of Ca2+ influx. PMID:3955298

  8. 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.

  9. Coronary pressure and flow relationships in humans: phasic analysis of normal and pathological vessels and the implications for stenosis assessment: a report from the Iberian–Dutch–English (IDEAL) collaborators

    PubMed Central

    Nijjer, Sukhjinder S.; de Waard, Guus A.; Sen, Sayan; van de Hoef, Tim P.; Petraco, Ricardo; Echavarría-Pinto, Mauro; van Lavieren, Martijn A.; Meuwissen, Martijn; Danad, Ibrahim; Knaapen, Paul; Escaned, Javier; Piek, Jan J.; Davies, Justin E.; van Royen, Niels

    2016-01-01

    Background Our understanding of human coronary physiological behaviour is derived from animal models. We sought to describe physiological behaviour across a large collection of invasive pressure and flow velocity measurements, to provide a better understanding of the relationships between these physiological parameters and to evaluate the rationale for resting stenosis assessment. Methods and results Five hundred and sixty-seven simultaneous intracoronary pressure and flow velocity assessments from 301 patients were analysed for coronary flow velocity, trans-stenotic pressure gradient (TG), and microvascular resistance (MVR). Measurements were made during baseline and hyperaemic conditions. The whole cardiac cycle and the diastolic wave-free period were assessed. Stenoses were assessed according to fractional flow reserve (FFR) and quantitative coronary angiography DS%. With progressive worsening of stenoses, from unobstructed angiographic normal vessels to those with FFR ≤ 0.50, hyperaemic flow falls significantly from 45 to 19 cm/s, Ptrend < 0.001 in a curvilinear pattern. Resting flow was unaffected by stenosis severity and was consistent across all strata of stenosis (Ptrend > 0.05 for all). Trans-stenotic pressure gradient rose with stenosis severity for both rest and hyperaemic measures (Ptrend < 0.001 for both). Microvascular resistance declines with stenosis severity under resting conditions (Ptrend < 0.001), but was unchanged at hyperaemia (2.3 ± 1.1 mmHg/cm/s; Ptrend = 0.19). Conclusions With progressive stenosis severity, TG rises. However, while hyperaemic flow falls significantly, resting coronary flow is maintained by compensatory reduction of MVR, demonstrating coronary auto-regulation. These data support the translation of coronary physiological concepts derived from animals to patients with coronary artery disease and furthermore, suggest that resting pressure indices can be used to detect the haemodynamic significance of coronary artery stenoses. PMID:26612582

  10. 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

  11. [New data on the pathogenesis of endometriosis interna].

    PubMed

    Damirov, M M; Kulakov, V I; Bakuleva, L P; Shabanov, A M; Sliusar', N N; Sarkisov, S E

    1993-01-01

    Eighty-six patients with histologically verified internal endometriosis were examined using histochemical, morphometric methods, and measurements of blood and myometrial tissue phosphatidyl inosites. Blood levels of phosphatidyl inosites were found reliably decreased in the patients vs. normal subjects, whereas their levels in myometrial tissue were significantly increased. Increased counts of tissue basophils, microcirculation disorders, lymphostasis and membranogenic stromal edema development were observed round endometriosis foci. Changes in the basic substance and fibrous structures of myometrial connective tissue complex were revealed, most marked in the areas adjacent to the endometrium. A possible mechanism of the development of pathologic shifts in internal endometriosis is discussed. PMID:8250133

  12. 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. PMID:22697126

  13. Noise-gated encoding of slow inputs by auditory brain stem neurons with a low-threshold K+ current.

    PubMed

    Gai, Yan; Doiron, Brent; Kotak, Vibhakar; Rinzel, John

    2009-12-01

    Phasic neurons, which do not fire repetitively to steady depolarization, are found at various stages of the auditory system. Phasic neurons are commonly described as band-pass filters because they do not respond to low-frequency inputs even when the amplitude is large. However, we show that phasic neurons can encode low-frequency inputs when noise is present. With a low-threshold potassium current (I(KLT)), a phasic neuron model responds to rising and falling phases of a subthreshold low-frequency signal with white noise. When the white noise was low-pass filtered, the phasic model also responded to the signal's trough but still not to the peak. In contrast, a tonic neuron model fired mostly to the signal's peak. To test the model predictions, whole cell slice recordings were obtained in the medial (MSO) and lateral (LSO) superior olivary neurons in gerbil from postnatal day 10 (P10) to 22. The phasic MSO neurons with strong I(KLT), mostly from gerbils aged P17 or older, showed firing patterns consistent with the preceding predictions. Moreover, injecting a virtual I(KLT) into weak-phasic MSO and tonic LSO neurons with putative weak or no I(KLT) (from gerbils younger than P17) shifted the neural response from the signal's peak to the rising phase. These findings advance our knowledge about how noise gates the signal pathway and how phasic neurons encode slow envelopes of sounds with high-frequency carriers. PMID:19812289

  14. 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

  15. 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.

  16. Alpha-1 adrenergic receptor: Binding and phosphoinositide breakdown in human myometrium

    SciTech Connect

    Breuiller-Fouche, M.; Doualla-Bell Kotto Maka, F.; Geny, B.; Ferre, F. )

    1991-07-01

    Alpha-1 adrenergic receptors were examined in both inner and outer layers of human pregnant myometrium using radioligand binding of (3H)prazosin. (3H)prazosin bound rapidly and reversibly to a single class of high affinity binding sites in myometrial membrane preparations. Scatchard analysis gave similar values of equilibrium dissociation constants in both myometrial layers. In contrast, more alpha-1 adrenergic receptors were detected in the outer layer than in the inner layer. Antagonist inhibited (3H)prazosin binding with an order of potency of prazosin greater than phentolamine greater than idazoxan. Competition experiments have also revealed that a stable guanine nucleotide decreases the apparent affinity of norepinephrine for myometrial (3H)prazosin binding sites. The functional status of these alpha-1 adrenergic receptors was also assessed by measuring the norepinephrine-induced accumulation of inositol phosphates in myometrial tissue. Norepinephrine produced a concentration-dependent accumulation of inositol phosphates in both myometrial layers. However, norepinephrine-induced increases in inositol 1,4,5-triphosphate were only observed in the outer layer. These results indicate that alpha-1 adrenergic receptors in human myometrium at the end of pregnancy are linked to phosphoinositide hydrolysis and that this response occurs mainly in the outer layer.

  17. 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.

  18. The onset of labor alters corticotropin-releasing hormone type 1 receptor variant expression in human myometrium: putative role of interleukin-1beta.

    PubMed

    Markovic, Danijela; Vatish, Manu; Gu, Mei; Slater, Donna; Newton, Rob; Lehnert, Hendrik; Grammatopoulos, Dimitris K

    2007-07-01

    CRH targets the human myometrium during pregnancy. The efficiency of CRH actions is determined by expression of functional receptors (CRH-R), which are dynamically regulated. Studies in myometrial tissue biopsies using quantitative RT-PCR demonstrated that the onset of labor, term or preterm, is associated with a significant 2- to 3-fold increase in CRH-R1 mRNA levels. Detailed analysis of myometrial CRH-R1 mRNA variants showed a decline of the pro-CRH-R1 mRNA encoding the CRH-R1beta variant during labor and increased mRNA levels of CRH-R1d mRNA. Studies in myometrial cells identified IL-1beta as an important regulator of myometrial CRH-R1 gene expression because prolonged treatment of myometrial cells with IL-1beta (1 ng/ml) for 18 h induced expression of CRH-R1 mRNA levels by 1.5- to 2-fold but significantly attenuated CRH-R1beta mRNA expression by 70%. In contrast, IL-1beta had no effect on CRH-R1d mRNA expression. Studies using specific inhibitors suggest that ERK1/2, p38 MAPK, and downstream nuclear translocation of nuclear factor-kappaB mediate IL-1beta effects on myometrial CRH-R1 gene. However, the increased CRH-R1 mRNA expression was associated with a dampening of the receptor efficacy to activate the adenylyl cyclase/cAMP signaling cascade. Thus, our findings suggest that IL-1beta is an important regulator of CRH-R1 expression and functional activity, and this interaction might play a role in the transition of the uterus from quiescence to active contractions necessary for the onset of parturition. PMID:17431005

  19. Paracrine activation of WNT/β-catenin pathway in uterine leiomyoma stem cells promotes tumor growth

    PubMed Central

    Ono, Masanori; Yin, Ping; Navarro, Antonia; Moravek, Molly B.; Coon, John S.; Druschitz, Stacy A.; Serna, Vanida Ann; Qiang, Wenan; Brooks, David C.; Malpani, Saurabh S.; Ma, Jiajia; Ercan, Cihangir Mutlu; Mittal, Navdha; Monsivais, Diana; Dyson, Matthew T.; Yemelyanov, Alex; Maruyama, Tetsuo; Chakravarti, Debabrata; Kim, J. Julie; Kurita, Takeshi; Gottardi, Cara J.; Bulun, Serdar E.

    2013-01-01

    Uterine leiomyomas are extremely common estrogen and progesterone-dependent tumors of the myometrium and cause irregular uterine bleeding, severe anemia, and recurrent pregnancy loss in 15–30% of reproductive-age women. Each leiomyoma is thought to arise from a single mutated myometrial smooth muscle stem cell. Leiomyoma side-population (LMSP) cells comprising 1% of all tumor cells and displaying tumor-initiating stem cell characteristics are essential for estrogen- and progesterone-dependent in vivo growth of tumors, although they have remarkably lower estrogen/progesterone receptor levels than mature myometrial or leiomyoma cells. However, how estrogen/progesterone regulates the growth of LMSP cells via mature neighboring cells is unknown. Here, we demonstrate a critical paracrine role of the wingless-type (WNT)/β-catenin pathway in estrogen/progesterone-dependent tumorigenesis, involving LMSP and differentiated myometrial or leiomyoma cells. Estrogen/progesterone treatment of mature myometrial cells induced expression of WNT11 and WNT16, which remained constitutively elevated in leiomyoma tissues. In LMSP cells cocultured with mature myometrial cells, estrogen-progesterone selectively induced nuclear translocation of β-catenin and induced transcriptional activity of its heterodimeric partner T-cell factor and their target gene AXIN2, leading to the proliferation of LMSP cells. This effect could be blocked by a WNT antagonist. Ectopic expression of inhibitor of β-catenin and T-cell factor 4 in LMSP cells, but not in mature leiomyoma cells, blocked the estrogen/progesterone-dependent growth of human tumors in vivo. We uncovered a paracrine role of the WNT/β-catenin pathway that enables mature myometrial or leiomyoma cells to send mitogenic signals to neighboring tissue stem cells in response to estrogen and progesterone, leading to the growth of uterine leiomyomas. PMID:24082114

  20. Regulation of the uterine contractile apparatus and cytoskeleton

    PubMed Central

    Morgan, Kathleen G

    2007-01-01

    Parturition at term, the end stage of a successful pregnancy occurs as a result of powerful, co-ordinated and periodic contractions of uterine smooth muscle (myometrium). To occur in a propitious manner, a high degree of control over the activation of a myometrial cell is required. We review the molecular mechanisms and structural composition of myometrial cells that may contribute to their increased contractile capacity at term. We focus attention on pathways that lead to the activation of filamentous networks traditionally labeled ‘contractile’ or ‘cytoskeletal’ yet draw attention to the fact that functional discrimination between these systems is not absolute. PMID:17582796

  1. 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.

  2. 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.

  3. 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.

  4. Application of First Principles Ni-Cd and Ni-H2 Battery Models to Spacecraft Operations

    NASA Technical Reports Server (NTRS)

    Timmerman, Paul; Bugga, Ratnakumar; DiStefano, Salvador

    1997-01-01

    The conclusions of the application of first principles model to spacecraft operations are: the first principles of Bi-phasic electrode presented model provides an explanation for many behaviors on voltage fading on LEO cycling.

  5. Modeling the Gabaergic Action of Etomidate on the Thalamocortical System

    PubMed Central

    Talavera, Jason A.; Esser, Steven K.; Amzica, Florin; Hill, Sean; Antognini, Joseph F.

    2008-01-01

    Background We have used a computational model of the thalamocortical system to investigate the effects of a GABAergic anesthetic (etomidate) on cerebral cortical and thalamic neuronal function. We examined the effects of phasic and tonic inhibition, as well as the relative importance of anesthetic action in the thalamus and cortex. Methods The amount of phasic GABAergic inhibition was adjusted in the model to simulate etomidate concentrations of between 0.25 and 2 μM, with the concentration range producing unconsciousness assumed to be between 0.25-0.5 μM. In addition, we modeled tonic inhibition separately, and then phasic and tonic inhibition together. We also introduced phasic and tonic inhibition into the cerebral cortex and thalamus separately to determine the relative importance of each of these structures to anesthetic-induced depression of the thalamocortical system. Results Phasic inhibition decreased cortical neuronal firing by 11-18% in the 0.25-0.5 μM range and by 38% at 2 μM. Tonic inhibition produced similar depression (11-21%) in the 0.25-0.5 μM range but 65% depression at 2 μM; phasic and tonic inhibition combined produced the most inhibition (76% depression at 2 μM). When the thalamus and cortex were separately subjected to phasic and tonic inhibition, cortical firing rates decreased less compared to when both structures were targeted. In the 0.25-0.5 μM range, cortical firing rate was minimally affected when etomidate action was simulated in the thalamus only. Conclusions This computational model of the thalamocortical system indicated that tonic GABAergic inhibition appears to be more important than phasic GABAergic inhibition (especially at larger etomidate concentrations), although both combined had the most effect on cerebral cortical firing rates. Furthermore, etomidate action in the thalamus, by itself, does not likely explain etomidate-induced unconsciousness. PMID:19095844

  6. 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

  7. Effect of induced thyroid dysfunction upon uterine responsiveness in strips from pregnant and nonpregnant rats.

    PubMed

    Medeiros, Y S; Calixto, J B

    1989-01-01

    The influence of thyroid dysfunction on rat myometrial responsiveness to oxytocin, acetylcholine, CaCl2 and BaCl2 was assessed in uterine strips from pregnant and nonpregnant rats. In preparations obtained from hypothyroid nonpregnant rats, oxytocin and acetylcholine concentration-response curves were significantly displaced to the left, whereas myometrial strips from hyperthyroid nonpregnant rats were only supersensitive to acetylcholine. In relation to the pregnant state, T3 treatment caused an increased myometrial sensitivity to both oxytocin and acetylcholine. In this condition, concentration-response curves for oxytocin did not differ from nonpregnant control animals, whereas acetylcholine was about 300-fold more potent at the ED50 levels compared with those in nonpregnant animals. Either in pregnant or nonpregnant state, maximal responses and ED50 to BaCl2 did not differ. In addition, thyroid dysfunction did not modify the pattern of CaCl2-induced contractions in isolated myometrial strips from pregnant rats. This data extended to the myometrium, previous evidence in the literature indicating that thyroid dysfunction may affect uterine responsiveness to agonists. PMID:2755963

  8. Inhibition by sildenafil of contractility of isolated non-pregnant human myometrium

    PubMed Central

    Winston, Aruldhas Blessed; Vazhudhi, Kaysina; Sen, Sumalya; Thomas, Elsy; Benjamin, Santhosh; Peedicayil, Jacob

    2015-01-01

    Objective: To investigate the ability of sildenafil to inhibit the contractility of isolated non pregnant human myometrium. Materials and Methods: The inhibitory effect of three concentrations (3, 10, and 30 µM) of sildenafil on 55 mM KCl-induced contractility of isolated non-pregnant human myometrium was studied. The ability of the guanylyl cyclase inhibitor ODQ (10 µM), the adenylyl cyclase inhibitor MDL-12,330A (10 µM), the non-specific potassium channel blocker TEA (2 mM), and the calcium-sensitive potassium (BKCa) channel blocker iberiotoxin (100 nM) to reverse the inhibition of 10 µM sildenafil on KCl-induced myometrial contractility was also studied. Results: Sildenafil produced a concentration-dependent inhibition of KCl-induced myometrial contractility that was statistically significant at all three concentrations of sildenafil used. The inhibition by 10 µM sildenafil of KCl-induced myometrial contractility was not reversed by the concurrent administration of ODQ or MDL-12,330A. The inhibition of 10 µM sildenafil of myometrial contractility was partially reversed by concurrent administration of TEA and totally and significantly reversed by the concurrent administration of iberiotoxin. Conclusions: These results suggest that sildenafil inhibits the contractility of isolated non-pregnant human myometrium. The results suggest that sildenafil does so by opening BKCa channels. PMID:26311996

  9. A Case of Live Birth after Uterine Reconstruction for Recurrent Cornual Ectopic Pregnancy following IVF Treatment

    PubMed Central

    Maruthini, Deivanayagam; Sharma, Vinay

    2013-01-01

    We present a case of recurrent ruptured right cornual ectopic pregnancies conceived after IVF. Following the second episode, a sonohysterography was undertaken to identify possible areas of scar weakness that may rupture with uterine distension in a future pregnancy. The scan revealed asymmetrical muscle thickness in the cornual regions, the right (6 mm) being thinner than the left (1.6 cm). Subsequently, an elective laparotomy was undertaken, and the cornua were reconstructed and thickened in several layers by bringing the laterally retracted myometrial fibres onto the reconstruction site. A sono-hysterography after surgery showed satisfactory (3-4 cm) myometrial thickness all around. A further cycle of IVF resulted in a singleton pregnancy. Pelvic scans confirmed normal intrauterine pregnancy without any myometrial thinning. She was delivered by an uneventful elective caesarean section at term. We propose that, in those who intend to have further pregnancies after a cornual ectopic pregnancy, a sono-hysterography is possibly the best investigative tool to assess myometrial integrity. This case demonstrates that in women with areas of muscle weakness it is possible to successfully perform an interval elective reconstructive surgery on the uterus that can result in an uneventful pregnancy and birth. PMID:23476844

  10. Complex effects of imatinib on spontaneous and oxytocin-induced contractions in human non-pregnant myometrium.

    PubMed

    Cretoiu, S M; Simionescu, A A; Caravia, L; Curici, A; Cretoiu, D; Popescu, L M

    2011-09-01

    Human myometrium includes two important cell populations involved in its contractility: smooth muscle fibers and interstitial cells. The pacemaking mechanism is not yet identified, but it is possible that myometrial smooth muscle cells contract in response to a signal generated by c-kit positive interstitial cells. The aim of this study was to investigate the effects of imatinib as a c-kit receptor antagonist on the spontaneous or oxytocin (OT) induced contractions of human non-pregnant myometrium in vitro. Myometrial strips were obtained from non-pregnant women (reproductive age) undergoing hysterectomy for benign indications. The strips were suspended in organ baths for recording of isometric tension. Imatinib effects were assessed on spontaneous contraction and after preexposure to OT.Direct exposure of myometrial strips to imatinib inhibits both amplitude and frequency of contractions (80-320 μM) in a dose dependent manner. Amplitude reverted back to 90% of the baseline amplitude by consequent addition of imatinib (until 480 μM). Total inhibition of myometrial contraction was obtained after addition of OT 60 nM. If myometrium was pre-exposed to OT (320 nM), imatinib 80-160 μm increased amplitude, while decreasing frequency. These data provide evidence that telocytes may be involved as modulators of the spontaneous contractions of the non-pregnant human uterus, via a tyrosine-kinase independent signaling pathway. PMID:21893472

  11. Failed transarterial embolization of subserosal uterine arteriovenous malformation

    PubMed Central

    Seo, Kyung Jin; Kim, Jin; Sohn, In Sook; Kwon, Han Sung; Park, Sang Woo

    2013-01-01

    Uterine arteriovenous malformation (AVM) is rare but potentially life-threatening from excessive vaginal bleeding. All uterine AVMs reported to date have been found in the endometrial or myometrial layers. Here we present a patient with a subserosal type AVM on the fundus of uterus, which spontaneously ruptured. PMID:24328024

  12. Stretch-induced uterine myocyte differentiation during rat pregnancy: involvement of caspase activation.

    PubMed

    Shynlova, Oksana; Dorogin, Anna; Lye, Stephen J

    2010-06-01

    Proliferation, differentiation, and apoptosis are three major processes by which the pregnant uterus maintains homeostasis to accommodate the growing fetus. We demonstrated previously that caspase activation in the pregnant rat myometrium at midgestation coincides with the transition from uterine hyperplasia to hypertrophy. We hypothesized that this transition was induced by stasis of myometrial blood flow (and subsequent hypoxia/ischaemia insult) resulting from acute myometrial stretch induced by a growing embryo. Therefore, we measured the expression of active caspase 3 and two hypoxia markers (transcription factor HIF1A and pimonidazole hydrochloride) in pregnant rat myometrium. To investigate the effect of gravidity we used unilaterally pregnant rats. Caspase 3 was activated only in the gravid horn of the unilaterally pregnant animals on Gestational Days 12-15. This activation was associated with high levels of HIF1A and pimonidazole immunostaining, which were limited to the circular myometrial layer of the gravid horn, indicative of hypoxia within this tissue. To isolate the effect of myometrial stretch applied by the growing fetus, we inserted an expandable polymer tube (intra-uterine expandable tube [IUET]) into the empty horn of Day 13 and Day 20 unilaterally pregnant rats. Tissue was collected 2, 14, and 24 h later. In the IUET-stretched empty horn, cleaved caspase 3 was activated at midgestation (Day 14), but not at late gestation (Day 21). We speculate that hypoxia resulting from mechanical stretch may activate caspase 3 within the pregnant myometrium only in the context of a specific endocrine environment. PMID:20181619

  13. Dynamic changes in the myometrium during the third stage of labor, evaluated using two-dimensional ultrasound, in women with normal and abnormal third stage of labor and in women with obstetric complications

    PubMed Central

    Patwardhan, Manasi; Hernandez-Andrade, Edgar; Ahn, Hyunyoung; Korzeniewski, Steven J; Schwartz, Alyse; Hassan, Sonia S; Romero, Roberto

    2015-01-01

    Objective To investigate dynamic changes in myometrial thickness during the third stage of labor. Methods Myometrial thickness was measured using ultrasound at one-minute time intervals during the third stage of labor in the mid-region of the upper and lower uterine segments in 151 patients including: women with a long third stage of labor (n=30), post-partum hemorrhage (n=4), preterm delivery (n=7) or clinical chorioamnionitis (n=4). Differences between uterine segments and as a function of time were evaluated. Results There was a significant linear increase in the mean myometrial thickness of the upper uterine segments, as well as a significant linear decrease in the mean myometrial thickness of the lower uterine segments until the expulsion of the placenta (p<0.001). The ratio of the measurements of the upper to the lower uterine segments increased significantly as a function of time (p<0.0001). In women with postpartum hemorrhage, preterm delivery and clinical chorioamnionitis, an uncoordinated pattern between the uterine segments was observed. Conclusion A well-coordinated activity between the upper and lower uterine segments is demonstrated in normal placental delivery. In some clinical conditions this pattern is not observed, increasing the time for placental delivery and the risk for post-partum hemorrhage. PMID:25634647

  14. IL-8 inhibits cAMP-stimulated alveolar epithelial fluid transport via a GRK2/PI3K-dependent mechanism

    PubMed Central

    Roux, Jérémie; McNicholas, Carmel M.; Carles, Michel; Goolaerts, Arnaud; Houseman, Benjamin T.; Dickinson, Dale A.; Iles, Karen E.; Ware, Lorraine B.; Matthay, Michael A.; Pittet, Jean-François

    2013-01-01

    Patients with acute lung injury (ALI) who retain maximal alveolar fluid clearance (AFC) have better clinical outcomes. Experimental and small clinical studies have shown that β2-adrenergic receptor (β2AR) agonists enhance AFC via a cAMP-dependent mechanism. However, two multicenter phase 3 clinical trials failed to show that β2AR agonists provide a survival advantage in patients with ALI. We hypothesized that IL-8, an important mediator of ALI, directly antagonizes the alveolar epithelial response to β2AR agonists. Short-circuit current and whole-cell patch-clamping experiments revealed that IL-8 or its rat analog CINC-1 decreases by 50% β2AR agonist-stimulated vectorial Cl− and net fluid transport across rat and human alveolar epithelial type II cells via a reduction in the cystic fibrosis transmembrane conductance regulator activity and biosynthesis. This reduction was mediated by heterologous β2AR desensitization and down-regulation (50%) via the G-protein-coupled receptor kinase 2 (GRK2)/PI3K signaling pathway. Inhibition of CINC-1 restored β2AR agonist-stimulated AFC in an experimental model of ALI in rats. Finally, consistent with the experimental results, high pulmonary edema fluid levels of IL-8 (>4000 pg/ml) were associated with impaired AFC in patients with ALI. These results demonstrate a novel role for IL-8 in inhibiting β2AR agonist-stimulated alveolar epithelial fluid transport via GRK2/PI3K-dependent mechanisms.—Roux, J., McNicholas, C. M., Carles, M., Goolaerts, A., Houseman, B. T., Dickinson, D. A., Iles, K. E., Ware, L. B., Matthay, M. A., Pittet, J.-F. IL-8 inhibits cAMP-stimulated alveolar epithelial fluid transport via a GRK2/PI3K-dependent mechanism. PMID:23221335

  15. 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

  16. Mathematical model of excitation-contraction in a uterine smooth muscle cell.

    PubMed

    Bursztyn, Limor; Eytan, Osnat; Jaffa, Ariel J; Elad, David

    2007-05-01

    Uterine contractility is generated by contractions of myometrial smooth muscle cells (SMCs) that compose most of the myometrial layer of the uterine wall. Calcium ion (Ca(2+)) entry into the cell can be initiated by depolarization of the cell membrane. The increase in the free Ca(2+) concentration within the cell initiates a chain of reactions, which lead to formation of cross bridges between actin and myosin filaments, and thereby the cell contracts. During contraction the SMC shortens while it exerts forces on neighboring cells. A mathematical model of myometrial SMC contraction has been developed to study this process of excitation and contraction. The model can be used to describe the intracellular Ca(2+) concentration and stress produced by the cell in response to depolarization of the cell membrane. The model accounts for the operation of three Ca(2+) control mechanisms: voltage-operated Ca(2+) channels, Ca(2+) pumps, and Na(+)/Ca(2+) exchangers. The processes of myosin light chain (MLC) phosphorylation and stress production are accounted for using the cross-bridge model of Hai and Murphy (Am J Physiol Cell Physiol 254: C99-C106, 1988) and are coupled to the Ca(2+) concentration through the rate constant of myosin phosphorylation. Measurements of Ca(2+), MLC phosphorylation, and force in contracting cells were used to set the model parameters and test its ability to predict the cell response to stimulation. The model has been used to reproduce results of voltage-clamp experiments performed in myometrial cells of pregnant rats as well as the results of simultaneous measurements of MLC phosphorylation and force production in human nonpregnant myometrial cells. PMID:17267547

  17. 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.

  18. 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

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

    PubMed Central

    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. PMID:10618438

  20. 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

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

    PubMed Central

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

    2010-01-01

    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. PMID:20616081

  2. Membrane current and contraction in frog atrial fibres

    PubMed Central

    Einwächter, H. M.; Haas, H. G.; Kern, R.

    1972-01-01

    1. Membrane current and mechanical activity were recorded from short segments of frog atrial muscle strips using a double sucrose gap voltage clamp arrangement. Experiments were performed at 4-7° C. Two types of contraction were observed dependent upon the duration of the clamp. 2. Short-lasting depolarizations caused a flow of Ca inward current, ICa, and development of a phasic contraction. Time to peak tension approximated 400 msec. Both ICa and contraction, as functions of membrane potential, had a threshold of about — 40 mV and were maximal at inside positive potentials in normal Ringer fluid. Peak tension decreased at strong depolarizations. 3. The minimum time of depolarization required for initiation of a phasic contraction was 40-70 msec. The time necessary for full activation of contraction was 200-300 msec and comparable to the period of time covered by the flow of ICa. 4. There was no marked change in peak tension upon repetitive depolarization to the same membrane potential. 5. Restoration of (phasic) contractility after a preceding contraction was strongly dependent on the level of membrane potential between conditioning and test pulse. Restoration was half complete at potentials around — 45 mV. 6. Long-lasting depolarizations generated tonic (sustained) contractions superimposed on the phasic (transient) ones. Threshold potential for initiation of tonic contractions was usually positive to the threshold of phasic contractions. The time taken to attain the final level of tension ranged between 0·7 and 3 sec. Plateau tension, as a function of membrane potential, increased with increasing depolarization and reached a flat maximum at about + 50 mV in normal Ringer fluid. 7. At membrane potentials near zero level, plateau tension developed by the tonic mechanism was about twice peak tension due to phasic contraction. 8. Removal of Ca ions from the external medium resulted in an almost complete abolition of phasic contraction within 1-2 min and a

  3. The physiological basis of the minimally distinct border demonstrated in the ganglion cells of the macaque retina.

    PubMed Central

    Kaiser, P K; Lee, B B; Martin, P R; Valberg, A

    1990-01-01

    1. The minimally distinct border method involves setting the relative radiances of two adjacent, differently coloured fields until the border between them is minimally distinct. At these radiance settings, the two fields are found to be of equal luminance. The task shares with flicker photometry all the requirements of a photometric method. 2. We have recorded responses of macaque ganglion cells to such borders moved back and forth across the receptive field; the size of the luminance step across the border was systematically varied. 3. Phasic ganglion cells gave transient responses to such borders, consisting of an increase or decrease in firing rate depending on direction of luminance contrast and cell type (on- or off-centre). Tonic ganglion cells gave sustained responses dependent on chromatic contrast across the border. 4. An analysis of phasic cell responses showed a minimum near equal luminance, suggesting their signal could readily support the minimally distinct border task. We could not devise a scheme whereby tonic cells could support the task. 5. Spectral sensitivity of phasic cells, determined from their minima, closely resembled the 10 deg luminous efficiency function, as required of a mechanism underlying the psychophysical performance. 6. For phasic cells, the minimum was independent of movement speed, and hence of eye movement velocity under natural viewing conditions. 7. Proportionality, additivity and transitivity are found psychophysically with the minimally distinct border method. All these properties were also exhibited by phasic cell responses. 8. Residual responses were present in individual phasic cells to equal-luminance borders, probably due to a non-linearity of M- and L-cone summation. The amplitude of residual response depended on the wavelengths on either side of the border, and was zero for pairs of lights lying along a tritanopic confusion line. These residual responses could be correlated with residual border distinctness at equal

  4. 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

  5. Efficacy of nifedipine therapy in patients with sphincter of Oddi dysfunction: a prospective, double-blind, randomized, placebo-controlled, cross over trial.

    PubMed Central

    Khuroo, M S; Zargar, S A; Yattoo, G N

    1992-01-01

    1. Twenty-eight patients who fulfilled entry criteria for sphincter of Oddi dysfunction were randomly allocated to receive nifedipine and placebo in a cross over design with 12 week treatment periods separated by a 2 week wash-out. 2. All patients had episodic pain resembling biliary pain, had previously undergone cholecystectomy, had elevated alkaline phosphatase during episodes of pain and had elevated basal pressure on sphincter of Oddi manometry. 3. Compared with placebo, significant decreases in cumulative pain score, number of pain episodes, oral analgesic tablets consumed and emergency room visits were observed during nifedipine treatment. 4. Overall 21 patients improved during nifedipine therapy while seven patients did not. None of the following predicted response to nifedipine therapy: enzyme levels, morphine-Prostigmine test, fatty meal sonography, common duct diameter and pressure, sphincter of Oddi phasic pressure, frequency and duration of phasic waves and maximal fall in the basal pressure at sphincter of Oddi manometry after sublingual administration of nifedipine. However patients with predominant antegrade propagation of phasic contractions of sphincter of Oddi did significantly better on nifedipine than those with abnormal propagation of phasic contractions. 5. Nifedipine therapy orally in maximal tolerated doses relieves pain in patients with sphincter of Oddi dysfunction who have elevated basal pressure and sphincter of Oddi phasic contractions of predominantly antegrade nature. PMID:1524959

  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. Platelet Activation Following Implant of the Levitronix PediVAS in the Ovine Model

    PubMed Central

    Johnson, Carl A.; Shankarraman, Venkat; Wearden, Peter D.; Kocyildirim, Ergin; Maul, Timothy M.; Marks, John D.; Richardson, J. Scott; Gellman, Barry N.; Borovetz, Harvey S.; Dasse, Kurt A.; Wagner, William R.

    2011-01-01

    The Levitronix PediVAS is an extracorporeal magnetically levitated pediatric ventricular assist system with an optimal flow rate range of 0.3 – 1.5 L/min. The system is being tested in preclinical studies to assess hemodynamic performance and biocompatibility. The PediVAS was implanted in 9 ovines for 30 days duration using either commercially available cannulae (N = 3) or customized Levitronix cannulae (N = 6). Blood biocompatibility in terms of circulating activated platelets was measured by flow cytometric assays to detect P-selectin. Platelet activation was further examined following exogenous agonist stimulation. Platelet activation rose following surgery and eventually returned to baseline in animal studies where minimal kidney infarcts were observed. Platelet activation remained elevated for the duration of the study in animals where a moderate number of kidney infarcts with or without thrombotic deposition in the cannulae were observed. When platelet activation did return to baseline, platelets appropriately responded to agonist stimulation signifying conserved platelet function following PediVAS implant. Platelet activation returned to baseline in the majority of studies, representing a promising biocompatibility result for the Levitronix PediVAS. PMID:21989419

  8. Chronic nonocclusive coronary artery constriction in rats. Beta-adrenoceptor signal transduction and ventricular failure.

    PubMed Central

    Meggs, L G; Huang, H; Li, P; Capasso, J M; Anversa, P

    1991-01-01

    To determine the effects of chronic coronary artery constriction on the relationship between cardiac function and regulation of beta-adrenoceptor signal transduction, the left main coronary artery was narrowed in rats and the animals were killed 5 mo later. An average reduction in coronary luminal diameter of 44% was obtained and this change resulted in an increase in left ventricular end-diastolic pressure and a decrease in positive and negative dP/dt. Significant increases in left and right ventricular weights indicative of global cardiac hypertrophy were observed. Radioligand binding studies of beta-adrenoreceptors, agonist-stimulated adenylate cyclase activity, and ADP ribosylation of 45-kD substrate by cholera toxin were all depressed in the failing left ventricle. In contrast, in the hypertrophic non-failing right ventricle, beta-adrenoreceptor density was preserved and receptor antagonist affinity was increased. In spite of these findings at the receptor level, agonist stimulated cyclic AMP generation was reduced in the right ventricular myocardium. The quantity of the 45-kD substrate was also decreased. In conclusion, longterm nonocclusive coronary artery stenosis of moderate degree has profound detrimental effects on the contractile performance of the heart in association with marked attenuation of adrenergic support mechanisms. Images PMID:1661293

  9. Nedd4 Mediates Agonist-dependent Ubiquitination, Lysosomal Targeting, and Degradation of the β2-Adrenergic Receptor*S⃞

    PubMed Central

    Shenoy, Sudha K.; Xiao, Kunhong; Venkataramanan, Vidya; Snyder, Peter M.; Freedman, Neil J.; Weissman, Allan M.

    2008-01-01

    Agonist-stimulated β2-adrenergic receptor (β2AR) ubiquitination is a major factor that governs both lysosomal trafficking and degradation of internalized receptors, but the identity of the E3 ubiquitin ligase regulating this process was unknown. Among the various catalytically inactive E3 ubiquitin ligase mutants that we tested, a dominant negative Nedd4 specifically inhibited isoproterenol-induced ubiquitination and degradation of the β2AR in HEK-293 cells. Moreover, siRNA that down-regulates Nedd4 expression inhibited β2AR ubiquitination and lysosomal degradation, whereas siRNA targeting the closely related E3 ligases Nedd4-2 or AIP4 did not. Interestingly, β2AR as well as β-arrestin2, the endocytic and signaling adaptor for the β2AR, interact robustly with Nedd4 upon agonist stimulation. However, β2AR-Nedd4 interaction is ablated when β-arrestin2 expression is knocked down by siRNA transfection, implicating an essential E3 ubiquitin ligase adaptor role for β-arrestin2 in mediating β2AR ubiquitination. Notably, β-arrestin2 interacts with two different E3 ubiquitin ligases, namely, Mdm2 and Nedd4 to regulate distinct steps in β2AR trafficking. Collectively, our findings indicate that the degradative fate of the β2AR in the lysosomal compartments is dependent upon β-arrestin2-mediated recruitment of Nedd4 to the activated receptor and Nedd4-catalyzed ubiquitination. PMID:18544533

  10. 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.

  11. N-terminal galanin-(1-16) fragment is an agonist at the hippocampal galanin receptor

    SciTech Connect

    Fisone, G.; Berthold, M.; Bedecs, K.; Unden, A.; Bartfai, T.; Bertorelli, R.; Consolo, S.; Crawley, J.; Martin, B.; Nilsson, S.; )

    1989-12-01

    The galanin N-terminal fragment (galanin-(1-16)) has been prepared by solid-phase synthesis and by enzymic cleavage of galanin by endoproteinase Asp-N. This peptide fragment displaced {sup 125}I-labeled galanin in receptor autoradiography experiments on rat forebrain and spinal cord and in equilibrium binding experiments from high-affinity binding sites in the ventral hippocampus with an IC50 of approximately 3 nM. In tissue slices of the same brain area, galanin-(1-16), similarly to galanin, inhibited the muscarinic agonist-stimulated breakdown of inositol phospholipids. Upon intracerebroventricular administration, galanin-(1-16) (10 micrograms/15 microliters) also inhibited the scopolamine (0.3 mg/kg, s.c.)-evoked release of acetylcholine, as studied in vivo by microdialysis. Substitution of (L-Trp2) for (D-Trp2) resulted in a 500-fold loss in affinity as compared with galanin-(1-16). It is concluded that, in the ventral hippocampus, the N-terminal galanin fragment (galanin-(1-16)) is recognized by the galanin receptors controlling acetylcholine release and muscarinic agonist-stimulated inositol phospholipid breakdown as a high-affinity agonist and that amino acid residue (Trp2) plays an important role in the receptor-ligand interactions.

  12. EEG and autonomic arousal measures in schizophrenics.

    PubMed

    Joseph, C

    1989-04-01

    EEG and autonomic indices were measured in basal, tonic, and phasic conditions in order to delineate the nature of arousal dysfunction in schizophrenics as compared to normals. The experimental procedure involved six continuous recording sessions consisting of a basal recording before and after four experimental series. Sequentially, these were the visual nonsignal (VNS), the auditory nonsignal (ANS), the visual signal (VS), and the auditory signal (AS) series. The main findings indicated significant differences between the two groups in cardiovascular indices during the basal and tonic conditions and in the EEG and EMG indices of phasic response. These results suggest a dysfunction of basal and tonic autonomic arousal and a modulatory impairement of the central phasic arousal reaction. The findings are in accordance with the two arousal hypothesis postulated by Routtenberg (1968) and disconfirm the unitary concept of arousal for the explanation of psychophysiological abnormality in schizophrenia. PMID:2744968

  13. 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.

  14. 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.

  15. Physiologic uterine inflammation and labor onset: integration of endocrine and mechanical signals.

    PubMed

    Shynlova, Oksana; Lee, Yu-Hui; Srikhajon, Khetsopon; Lye, Stephen J

    2013-02-01

    The mechanisms underlying the preparation of the uterus for labor are not fully understood. Our previous studies have shown that during pregnancy, the uterine muscle (myometrium) undergoes dramatic phenotypic modulation culminating in term labor. The current review will discuss the cellular mechanisms involved in the regulation of myometrial activity and its modulation by endocrine signals and by mechanical stimulation of the uterus by the growing fetus. In particular, the contribution of uterine inflammation to the onset of labor will be described. We provide evidence that increased production of cytokines/chemokines in pregnant myometrium is associated with uterine occupancy and regulated by progesterone, suggesting the integration of mechanical and endocrine signals. Myometrial cells can actively participate in the inflammatory process in the uterus through the release of multiple proinflammatory cytokines and chemokines, providing a strong signal for activation of immune cells, their subsequent infiltration into pregnant uterus, and the initiation of labor. PMID:22614625

  16. MR staging in carcinoma of the endometrium and carcinoma of the cervix.

    PubMed Central

    Pakkal, M. V.; Rudralingam, V.; McCluggage, W. G.; Kelly, B. E.

    2004-01-01

    This study aimed to evaluate MR as an imaging modality for the assessment of myometrial and cervical invasion in endometrial carcinoma and for the assessment of parametrial and lymph node involvement in cervical carcinoma. Twenty-eight patients with a preoperative histological diagnosis of endometrial carcinoma/cervical carcinoma were included in the study. The findings were compared with the surgical staging and the histopathological report of the hysterectomy specimen. Accuracy in detecting myometrial and cervical involvement in patients with endometrial carcinoma was 78% for both. Accuracy in detecting parametrial and lymph node involvement in patients with cervical carcinoma was 71% and 86% respectively. MR is a reliable method for preoperative assessment of endometrial and cervical carcinoma. It helps decide operability, the type of operation and aids in the selection of patients who need to be considered for specialist referral to a gynaecologist oncologist. PMID:15244121

  17. Analysis of residual disease following preoperative radiotherapy versus initial surgery in endometrial carcinoma

    SciTech Connect

    Chung, C.K.; Stryker, J.A.; Nahhas, W.A.; Cunningham, D.E.; Mortel, R.

    1982-02-01

    A clinicopathologic study of residual disease following pre-operative radiotherapy (RT) in 67 patients and initial surgery in 40 patients with early invasive endometrial carcinoma is presented. In 10%, extrauterine spread was found at operation. In 10% of patients, the histologic type, and in 19% the grade of tumor, differed between the curettage and hysterectomy specimens. Pre-op RT altered the depth of myometrial invasion and frequency of vascular invasion, but there was no evidence that irradiation itself affected the histologic type or grade of tumor. The patients with residual tumor after pre-op RT had significantly more cancer-related deaths than those without residual disease. The high risk factors were deep myometrial invasion and residual disease outside the uterus. Vascular invasion did not affect the prognosis in this series. The importance of surgical-pathologic staging by initial surgery is discussed.

  18. 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.

  19. 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.

  20. Complementary processing of haptic information by slowly and rapidly adapting neurons in the trigeminothalamic pathway. Electrophysiology, mathematical modeling and simulations of vibrissae-related neurons

    PubMed Central

    Sanchez-Jimenez, Abel; Torets, Carlos; Panetsos, Fivos

    2013-01-01

    Tonic (slowly adapting) and phasic (rapidly adapting) primary afferents convey complementary aspects of haptic information to the central nervous system: object location and texture the former, shape the latter. Tonic and phasic neural responses are also recorded in all relay stations of the somatosensory pathway, yet it is unknown their role in both, information processing and information transmission to the cortex: we don't know if tonic and phasic neurons process complementary aspects of haptic information and/or if these two types constitute two separate channels that convey complementary aspects of tactile information to the cortex. Here we propose to elucidate these two questions in the fast trigeminal pathway of the rat (PrV-VPM: principal trigeminal nucleus-ventroposteromedial thalamic nucleus). We analyze early and global behavior, latencies and stability of the responses of individual cells in PrV and medial lemniscus under 1–40 Hz stimulation of the whiskers in control and decorticated animals and we use stochastic spiking models and extensive simulations. Our results strongly suggest that in the first relay station of the somatosensory system (PrV): (1) tonic and phasic neurons process complementary aspects of whisker-related tactile information (2) tonic and phasic responses are not originated from two different types of neurons (3) the two responses are generated by the differential action of the somatosensory cortex on a unique type of PrV cell (4) tonic and phasic neurons do not belong to two different channels for the transmission of tactile information to the thalamus (5) trigeminothalamic transmission is exclusively performed by tonically firing neurons and (6) all aspects of haptic information are coded into low-pass, band-pass, and high-pass filtering profiles of tonically firing neurons. Our results are important for both, basic research on neural circuits and information processing, and development of sensory neuroprostheses. PMID:23761732

  1. Basal activity of voltage-gated Ca(2+) channels controls the IP3-mediated contraction by α(1)-adrenoceptor stimulation of mouse aorta segments.

    PubMed

    Leloup, Arthur J; Van Hove, Cor E; De Meyer, Guido R Y; Schrijvers, Dorien M; Fransen, Paul

    2015-08-01

    α1-Adrenoceptor stimulation of mouse aorta causes intracellular Ca(2+) release from sarcoplasmic reticulum Ca(2+) stores via stimulation of inositoltriphosphate (IP3) receptors. It is hypothesized that this Ca(2+) release from the contractile and IP3-sensitive Ca(2+) store is under the continuous dynamic control of time-independent basal Ca(2+) influx via L-type voltage-gated Ca(2+) channels (LCC) residing in their window voltage range. Mouse aortic segments were α1-adrenoceptor stimulated with phenylephrine in the absence of external Ca(2+) (0Ca) to measure phasic isometric contractions. They gradually decreased with time in 0Ca, were inhibited with 2-aminoethoxydiphenyl borate, and declined with previous membrane potential hyperpolarization (levcromakalim) or with previous inhibition of LCC (diltiazem). Former basal stimulation of LCC with depolarization (15 mM K(+)) or with BAY K8644 increased the subsequent phasic contractions by phenylephrine in 0Ca. Although exogenous NO (diethylamine NONOate) reduced the phasic contractions by phenylephrine, stimulation of endothelial cells with acetylcholine in 0Ca failed to attenuate these phasic contractions. Finally, inhibition of the basal release of NO with N(Ω)-nitro-L-arginine methyl ester also attenuated the phasic contractions by phenylephrine. Results indicated that α1-adrenoceptor stimulation with phenylephrine causes phasic contractions, which are controlled by basal LCC and endothelial NO synthase activity. Endothelial NO release by acetylcholine was absent in 0Ca. Given the growing interest in the active regulation of arterial compliance, the dependence of contractile SR Ca(2+) store-refilling in basal conditions on the activity of LCC and basal eNOS may contribute to a more thorough understanding of physiological mechanisms leading to arterial stiffness. PMID:25913240

  2. Single-cell mechanics and calcium signalling in organotypic slices of human myometrium.

    PubMed

    Loftus, Fiona C; Richardson, Magnus J E; Shmygol, Anatoly

    2015-06-25

    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 ([Ca(2+)]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 [Ca(2+)]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 [Ca(2+)]i dynamics in control and oxytocin stimulated slices of human myometrium on a cellular level. We present evidence that oxytocin induces asynchronous [Ca(2+)]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 [Ca(2+)]i transients but appear to be unrelated to contractions. Furthermore, the oxytocin-triggered [Ca(2+)]i oscillations wane within 30-50min of hormone application, while the action potential induced [Ca(2+)]i transients remain augmented. We conclude that oxytocin-induced [Ca(2+)]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. Uterine activity, sperm transport, and the role of boar stimuli around insemination in sows.

    PubMed

    Langendijk, P; Soede, N M; Kemp, B

    2005-01-15

    This paper describes changes in spontaneous myometrial activity around estrus, factors that affect myometrial activity, and the possible role of uterine contractions in the process of (artificial) insemination, sperm transport and fertilization. Myometrial activity in the sow increases during estrus. The activity is myogenic in origin, but several factors have been shown to affect myometrial activity. Natural mating stimulates uterine contractions through several mechanisms. The presence of a boar, rather than the act of mating, induces central oxytocin release in the sow and thus increases uterine activity. Estrogens in the ejaculate of a boar can trigger prostaglandin release by the endometrium and thus increase uterine activity. Tactile stimulation of the genital tract (cervix) or tactile stimulation of the back and flanks of the sow during artificial insemination does not cause a release of oxytocin. There is hardly any evidence for the effects of these latter stimuli on uterine activity, and if they are present at all, the effects are very small. Evidence for the effects of synthetic boar odor on oxytocin release and/or uterine activity is inconsistent. The mere presence of a boar during insemination, in contrast, clearly stimulates uterine activity through the release of oxytocin. Hormonal stimulation (intrauterine) of uterine activity with estrogens, prostaglandins, or oxytocins before, during or after insemination generally improves fertilization rate, especially in situations with reduced fertility. Therefore, uterine contractions are believed to play an important role in the transport of sperm cells to the oviducts after insemination. Whether uterine contractions are absolutely necessary for sperm transport through the uterine horns, however, is not clear. Intensive stimulation of uterine contractions using hormones can also reduce the fertilization rate, probably by increasing the reflux of sperm cells during insemination. In this respect, the presence

  4. Physiological increases in lactate inhibit intracellular calcium transients, acidify myocytes and decrease force in term pregnant rat myometrium.

    PubMed

    Hanley, Jacqui-Ann; Weeks, Andrew; Wray, Susan

    2015-10-15

    Lactate is increased in myometrial capillary blood from women in slow or non-progressive labour (dystocia), suggesting that it is detrimental to uterine contractions. There are, however, no studies of the effect of lactate on the myometrium. We therefore investigated its effects and mechanism of action on myometrial strips from term pregnant rats. The effects on spontaneous and oxytocin-induced contractility in response to sodium lactate and other weak acids (1-20 mM) were studied. In some experiments, simultaneous force and intracellular Ca(2+) or pH (pH(i)) were measured with Indo-1 or Carboxy-SNARF, respectively. Statistical differences were tested using non-parametric tests. Lactate significantly decreased spontaneous contractility with an EC50 of 3.9 mM. Propionate, butyrate and pyruvate also reduced contractions with similar potency. The effects of lactate were reduced in the presence of oxytocin but remained significant. Lactate decreased pH(i) and nulling the decrease in pH(i) abolished its effects. We also show that lactate inhibited Ca(2+) transients, with these changes mirroring those produced on force. If Ca(2+) entry was enhanced by depolarization (high KCl) or applying the Ca(2+) channel agonist, Bay K 4644, the effects of lactate were abolished. Taken together, these data show that lactate in the physiological range potently decreases myometrial contractility as a result of its inhibition of Ca(2+) transients, which can be attributed to the induced acidification. The present study suggests that the accumulation of extracellular lactate will reduce myometrial contractions and could therefore contribute to labour dystocia. PMID:26223765

  5. The effects of female sexual hormones on the expression and function of α1A- and α1D-adrenoceptor subtypes in the late-pregnant rat myometrium.

    PubMed

    Bóta, Judit; Hajagos-Tóth, Judit; Ducza, Eszter; Samavati, Reza; Borsodi, Anna; Benyhe, Sándor; Gáspár, Róbert

    2015-12-15

    The aim of the study was to investigate the roles of α1-adrenoceptor subtypes in the last-day pregnant rat uterus in vitro by the administration of subtype-specific antagonists (the α1A-adrenoceptor antagonist WB 4101 and the α1D-adrenoceptor antagonist BMY 7378) after 17β-estradiol or progesterone pretreatment. In isolated organ bath studies, contractions were elicited with (-)-noradrenaline (10(-8)-10(-5)M) in the presence of propranolol (10(-5)M) and yohimbine (10(-6)M) in order to avoid β-, and α2-adrenergic action. The myometrial expressions of the α1-adrenoceptor subtypes were determined by means of the real time reverse transcription-polymerase chain reaction (RT-PCR) and Western blotting techniques. The activated G protein levels were investigated through radiolabelled GTP binding assays. Both 17β-estradiol and progesterone pretreatment changed the myometrial contracting effect of (-)-noradrenaline. In the presence of WB 4101, progesterone pretreatment decreased the (-)-noradrenaline-induced myometrial contraction. In the presence of BMY 7378, both the 17β-estradiol and the progesterone pretreatment reduced the effect of (-)-noradrenaline. The mRNA and protein expressions of the α1A-adrenoceptors were decreased after 17β-estradiol pretreatment. (-)-Noradrenaline increased the [(35)S]GTPγS binding of the α1-adrenoceptors, which was most markedly elevated by progesterone. Pertussis toxin inhibited the [(35)S]GTPγS binding-stimulating effect of (-)-noradrenaline, indicating the role of Gi proteins in the signal mechanisms. 17β-estradiol pretreatment blocks the expression of the α1A-adrenoceptors, whereas it does not influence the expression of the α1D-adrenoceptors. Progesterone pretreatment does not have any effect on the myometrial mRNA and protein expressions of the α1-adrenoceptors, but it alters the G protein coupling of these receptors, promoting a Gi-dependent pathway. PMID:26593425

  6. 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. PMID:21865584

  7. Distension of the uterus induces HspB1 expression in rat uterine smooth muscle.

    PubMed

    White, B G; MacPhee, D J

    2011-11-01

    The uterine musculature, or myometrium, demonstrates tremendous plasticity during pregnancy under the influences of the endocrine environment and mechanical stresses. Expression of the small stress protein heat shock protein B1 (HspB1) has been reported to increase dramatically during late pregnancy, a period marked by myometrial hypertrophy caused by fetal growth-induced uterine distension. Thus, using unilaterally pregnant rat models and ovariectomized nonpregnant rats with uteri containing laminaria tents to induce uterine distension, we examined the effect of uterine distension on myometrial HspB1 expression. In unilaterally pregnant rats, HspB1 mRNA and Ser(15)-phosphorylated HspB1 (pSer(15) HspB1) protein expression were significantly elevated in distended gravid uterine horns at days 19 and 23 (labor) of gestation compared with nongravid horns. Similarly, pSer(15) HspB1 protein in situ was only readily detectable in the distended horns compared with the nongravid horns at days 19 and 23; however, pSer(15) HspB1 was primarily detectable in situ at day 19 in membrane-associated regions, while it had primarily a cytoplasmic localization in myometrial cells at day 23. HspB1 mRNA and pSer(15) HspB1 protein expression were also markedly increased in ovariectomized nonpregnant rat myometrium distended for 24 h with laminaria tents compared with empty horns. Therefore, uterine distension plays a major role in the stimulation of myometrial HspB1 expression, and increased expression of this small stress protein could be a mechanoadaptive response to the increasing uterine distension that occurs during pregnancy. PMID:21900647

  8. 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

  9. Gene expression analysis of early stage endometrial cancers reveals unique transcripts associated with grade and histology but not depth of invasion.

    PubMed

    Risinger, John I; Allard, Jay; Chandran, Uma; Day, Roger; Chandramouli, Gadisetti V R; Miller, Caela; Zahn, Christopher; Oliver, Julie; Litzi, Tracy; Marcus, Charlotte; Dubil, Elizabeth; Byrd, Kevin; Cassablanca, Yovanni; Becich, Michael; Berchuck, Andrew; Darcy, Kathleen M; Hamilton, Chad A; Conrads, Thomas P; Maxwell, G Larry

    2013-01-01

    Endometrial cancer is the most common gynecologic malignancy in the United States but it remains poorly understood at the molecular level. This investigation was conducted to specifically assess whether gene expression changes underlie the clinical and pathologic factors traditionally used for determining treatment regimens in women with stage I endometrial cancer. These include the effect of tumor grade, depth of myometrial invasion and histotype. We utilized oligonucleotide microarrays to assess the transcript expression profile in epithelial glandular cells laser microdissected from 79 endometrioid and 12 serous stage I endometrial cancers with a heterogeneous distribution of grade and depth of myometrial invasion, along with 12 normal post-menopausal endometrial samples. Unsupervised multidimensional scaling analyses revealed that serous and endometrioid stage I cancers have similar transcript expression patterns when compared to normal controls where 900 transcripts were identified to be differentially expressed by at least fourfold (univariate t-test, p < 0.001) between the cancers and normal endometrium. This analysis also identified transcript expression differences between serous and endometrioid cancers and tumor grade, but no apparent differences were identified as a function of depth of myometrial invasion. Four genes were validated by quantitative PCR on an independent set of cancer and normal endometrium samples. These findings indicate that unique gene expression profiles are associated with histologic type and grade, but not myometrial invasion among early stage endometrial cancers. These data provide a comprehensive perspective on the molecular alterations associated with stage I endometrial cancer, particularly those subtypes that have the worst prognosis. PMID:23785665

  10. Endometrial cancer following radiation therapy for cervical cancer

    SciTech Connect

    Gallion, H.H.; van Nagell, J.R. Jr.; Donaldson, E.S.; Powell, D.E.

    1987-05-01

    The clinical and histologic features of eight cases of carcinoma of the endometrium which developed following radiation therapy for squamous cell carcinoma of the cervix are described. No patient had a well-differentiated tumor and significant myometrial invasion was present in all cases. Three of the eight tumors were papillary serous adenocarcinoma. Five of the eight patients developed recurrent tumor and died of their disease. The risk of endometrial cancer in patients previously radiated for cervical cancer is evaluated.

  11. Bowel injury from rollerball ablation of the endometrium.

    PubMed

    Kivnick, S; Kanter, M H

    1992-05-01

    A woman underwent apparently uneventful rollerball endometrial ablation but presented with an acute abdomen 2 days later. At laparotomy, a large uterine serosal burn was found and a nearby loop of ileum contained two small injuries: a serosal burn and a perforation. The ileal injuries were oversewn and the patient recovered. Pathologic examination of the uterus showed full-thickness coagulative myometrial necrosis but no uterine perforation. More experience is needed to establish the incidence of this complication. PMID:1565382

  12. Differing In Vitro Potencies of Tocolytics and Progesterone in Myometrium From Singleton and Twin Pregnancies.

    PubMed

    Arrowsmith, Sarah; Neilson, James; Bricker, Leanne; Wray, Susan

    2016-01-01

    We compared the relaxant effect of 2 known tocolytics; indomethacin and atosiban and progesterone, on pregnant human myometrial spontaneous and oxytocin-induced contractions from singleton and twin pregnancies. All agents exerted a concentration-dependent relaxant effect on myometrial contractions. There was no significant difference in the concentration-response curves between singletons and twins for progesterone or indomethacin on spontaneous contractions or atosiban on oxytocin-induced contraction. Under oxytocin however, the concentration-response curves for indomethacin and progesterone were significantly shifted to the right for both amplitude of contraction (P < .01) and activity integral (P < .01). When compared to singleton myometrium however, the concentration-response curves were significantly shifted to the right in the twin myometrium group (P < .05 progesterone and P < .001 indomethacin). We conclude that a greater concentration of progesterone and indomethacin is required to inhibit oxytocin-induced myometrial contractions in twins compared to singletons in vitro. The differences noted in the tissue pharmacologies may have implications for the successful prevention or inhibition of preterm labor in twin pregnancy. PMID:26239389

  13. Tissue-Specific Stem Cells in the Myometrium and Tumor-Initiating Cells in Leiomyoma1

    PubMed Central

    Ono, Masanori; Bulun, Serdar E.; Maruyama, Tetsuo

    2014-01-01

    ABSTRACT Tissue-specific (or somatic) stem cells constitute a subset of cells residing in normal adult tissues. By undergoing asymmetric division, they retain their ability to self-renew while producing daughter cells that go on to differentiate and play a role in tissue regeneration and repair. The human uterus consists primarily of endometrium and myometrium (the smooth muscle layer) that rapidly enlarges through its tremendous regenerative and remodeling capacity to accommodate the developing fetus. Such uterine enlargement and remodeling can take place repeatedly and cyclically over the course of a woman's reproductive life. These unique properties of the uterus suggest the existence of endometrial and myometrial stem cell systems. In addition, like somatic cells, tumor stem cells or tumor-initiating cells, a subset of cells within a tumor, retain the ability to reconstitute tumors. Uterine smooth muscle cells are thought to be the origin of leiomyomas that are the most common type of gynecologic tumor. Recent work has identified, isolated, and characterized putative stem/progenitor cells in the myometrium and in leiomyomas. Here, we review current studies of myometrial and leiomyoma stem/progenitor cells and provide a new paradigm for understanding myometrial physiology and pathology and how these cells might contribute to uterine remodeling during pregnancy and the formation of leiomyomas. The role of the WNT/CTNNB1 pathway in the pathogenesis of leiomyoma is also discussed. PMID:25376230

  14. [Effect of the combination of the beta-1-blocker metoprolol with the tocolytic fenoterol on uteroplacental hemodynamics and fetal cardiovascular sensitivity with particular consideration of intrauterine fetal malnutrition. Results of animal experiments].

    PubMed

    Wischnik, A; Heimisch, W; Wischnik, B; Schroll, A; Mendler, N; Wieshammer, E; Weidenbach, A

    1982-01-01

    7 merino sheep in an advanced state of pregnancy received oxytocin for labour induction under the conditions of control, monotherapy with the beta 2-adrenergic tocolytic fenoterol, combination of the latter with the beta 1-blocking substance metoprolol (Beloc). Likewise, the effect of labour induction was investigated when putting an artificial stenosis around the a. uterina during simultaneous application of fenoterol alone and combined with metoprolol. The following parameters were measured: aortic pressure and heart rate both in dam and fetus, maternal left ventricular pressure rising velocity, intrauterine pressure, uterine blood flow, uterine vascular resistance and regional myometrial contraction patterns by means of an ultrasonic transit time method. Measurement of maternal cardiovascular parameters once more showed, that maternal cardiovascular derangements could excellently be antagonised by metoprolol. Intrauterine pressure measurements as well as regional myometrial contraction patterns proved evidence, that there is no counteraction between the beta 2-mimetic substance and the beta 1-blocking agent concerning the tocolytic effect. When artificially stenosing the a. uterina, a rise in uterine contraction status could be observed; this hypoxic augmentation of myometrial tone could almost completely be reverted when combining fenoterol and metoprolol. Finally, no difference could be observed in the reaction of fetal cardiovascular parameters to reduced uterine blood flow before and after application of the beta 1-blocking substance metoprolol. PMID:6891248

  15. Effects of local anesthetics on contractions of pregnant and non-pregnant rat myometrium in vitro.

    PubMed

    Wei, Jin-Song; Jin, Zhe-Bin; Yin, Zhi-Qiang; Xie, Qiang-Min; Chen, Ji-Qiang; Li, Zi-Gang; Tang, Hui-Fang

    2014-06-01

    In order to determine whether local anesthetics directly affect the propagation and strength of myometrial contractions, we compared the effects of bupivacaine, ropivacaine, lidocaine and tetracaine on the contractions of myometrium isolated from pregnant and non-pregnant rats. Full-thickness myometrial strips were obtained from 18- to 21-day pregnant and non-pregnant Sprague-Dawley rats and incubated in an organ bath. When spontaneous contractions became regular, strips were exposed to cumulative concentrations of the four local anesthetics ranging from 0.01 to 300 μmol/L and the amplitude and frequency of contraction were recorded. All four compounds caused a concentration-dependent inhibition of the contractility of pregnant and non-pregnant uterine muscle. In pregnant myometrium, the concentration that caused 50% inhibition (IC(50)) was 100 μmol/L for bupivacaine, 157 μmol/L for ropivacaine, > 1000 μmol/L for lidocaine, and 26.3 μmol/L for tetracaine. In non-pregnant myometrium, the IC(50) was 26.9 μmol/L for bupivacaine, 40 μmol/L for ropivacaine, 384 μmol/L for lidocaine, and 7.4 μmol/L for tetracaine. These results suggested that local anesthetics do inhibit myometrial contractions in pregnant and non-pregnant rats in a concentration-dependent manner. PMID:24901082

  16. 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.

  17. 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

  18. Uterine endoplasmic reticulum stress-unfolded protein response regulation of gestational length is caspase-3 and -7-dependent.

    PubMed

    Kyathanahalli, Chandrashekara; Organ, Kenna; Moreci, Rebecca S; Anamthathmakula, Prashanth; Hassan, Sonia S; Caritis, Steve N; Jeyasuria, Pancharatnam; Condon, Jennifer C

    2015-11-10

    We previously identified myometrial caspase-3 (CASP3) as a potential regulator of uterine quiescence. We also determined that during pregnancy, the functional activation of uterine CASP3 is likely governed by an integrated endoplasmic reticulum stress response (ERSR) and is consequently limited by an increased unfolded protein response (UPR). The present study examined the functional relevance of uterine UPR-ERSR in maintaining myometrial quiescence and regulating the timing of parturition. In vitro analysis of the human uterine myocyte hTERT-HM cell line revealed that tunicamycin (TM)-induced ERSR modified uterine myocyte contractile responsiveness. Accordingly, alteration of in vivo uterine UPR-ERSR using a pregnant mouse model significantly modified gestational length. We determined that "normal" gestational activation of the ERSR-induced CASP3 and caspase 7 (CASP7) maintains uterine quiescence through previously unidentified proteolytic targeting of the gap junction protein, alpha 1(GJA1); however, surprisingly, TM-induced uterine ERSR triggered an exaggerated UPR that eliminated uterine CASP3 and 7 tocolytic action precociously. These events allowed for a premature increase in myometrial GJA1 levels, elevated contractile responsiveness, and the onset of preterm labor. Importantly, a successful reversal of the magnified ERSR-induced preterm birth phenotype could be achieved by pretreatment with 4-phenylbutrate, a chaperone protein mimic. PMID:26504199

  19. An audit of histopathology reports of carcinoma endometrium: Experience from a tertiary referral center

    PubMed Central

    Deodhar, KK; Rekhi, B; Menon, S; Ganesh, B

    2015-01-01

    Background: The aim was to see, compliance to minimum data information in carcinoma endometrium reports, in a team of 13 pathologists, and also to analyze these parameters e.g. tumor size, type, grade, depth of myometrial invasion, lymph node yield, pTNM stage etc. Materials and Methods: Reports of 114 cases of carcinoma endometrium, that were operated in-house during the years 2008 to 2010 were analyzed from the files of the Pathology department of our hospital. Results: The median age was 58.04 years and median tumor size was 4 cm. Endometrioid adenocarcinoma was the most common type (82.5%), followed by malignant mixed Mullerian tumor (MMMT) (6.1%) and Serous carcinoma (3.5%). Grade 2 was the commonest tumor grade (42.1%). Less than half of myometrial invasion was seen in 50% of the cases and more than half of the myometrial invasion was seen in 46.5% of cases. (Information was not available in four cases). Parametrial involvement was seen in 5.3% cases. The pTNM stage was not mentioned in 71.9% reports. The median lymph node yield was 15. Conclusion: The compliance to adhere to and to provide minimum data information in carcinoma endometrium reports is generally good. Lymph node yield is reasonable. Mentioning of pTNM staging is to be done more meticulously. Use of proformas/checklists is recommended. PMID:25766338

  20. [The experimental examination of the effect on the uterine blood flow of angiotensin II during pregnancy (author's transl)].

    PubMed

    Schmidt, A W

    1976-10-15

    In experiments with animals it was investigated the endurance of the myometrial and the blood flow of the renal cortex during endogenous pressure substances. At the same time it was tested, if treatment with sexual hormones or a pregnancy had the tested principles and changes through pressure substances, and that the changes were significant. The investigations were conducted on three groups of female rabbits. The blood changes in myometrial and in the uterine were measured and continually registered with the special heated thermistor, from the principle of the thermoclearance. The success of the blood pressure was intraarterial measured with an electric mechanism. Precisely the same doses (in relativity of the animals weight) of pressure substances were applied with an infusions pump intravenously. And pressure substances Angiotensin II, Norepinephrine and Epinephrine, and their actions on the blood pressure and blood flow through the myometrium and through the renal cortex were examined. Altogether 131 values were registered. The results of the study that were statistically secure were as follows: a) The uterine blood flow pro tissue volume unit stays constant also by pregnancy or pseudopregnancy. b) The blood flow of the kidney is perhaps twice as high as the myometrial. c) The myometrial blood flow is with the arterial systolic blood pressure tightly correlated. Blood pressure increases through Angiotensin-infusion and also recovery of the uterine blood flow. d) An autoregulation of the uterine blood flow is not observed. e) The decrease of the renal blood flow after the giving of pressure substances was not modified through pregnancy. f) In quality the behaviour of the organ blood flow is the same after applied infusion of the pressure substances. Quantity differences exist however between Angiotensin II, Norepinephrine and Epinephrine. The method of measuring the blood flow through the uterus and in the kidney was placed in one view there. The finding of

  1. The effect of Mn2+, Zn2+, Ba2+ and Ca2+ on spontaneous motility in sheep duodenum in vitro.

    PubMed

    Murillo, M D; Plaza, M A; Arruebo, M P

    1997-01-01

    1. The effects of several ions, Mn2+, Zn2+, Ba2+ and Ca2+, on spontaneous motility were investigated in longitudinal smooth muscle strips from sheep duodenum, in vitro. 2. Mn2+ (0.5-1.5 mM) and Zn2+ (0.5-5 mM) inhibited both the amplitude and frequency of motility in Krebs solution and in Ca(2+)-free medium. 3. Ba2+ (0.5-5 mM) evoked three types of contractile responses: (i) an increase in the frequency and a reduction of the amplitude of spontaneous contractions; (ii) a slight increase in muscle tone of the phasic contractions; and (iii) a rapid initial phasic contraction followed by slowly fading contraction. Ca2+ induced two kinds of responses in spontaneous motility: (i) a fast phasic contraction, followed by an increase in the amplitude and frequency of phasic contractions with no changes in its tone; and (ii) an increase in the amplitude of contractions. 4. The Ba(2+)-induced contractions were inhibited by EDTA, verapamil and diltiazem, but were not modified by sodium nitroprusside. The Ca(2+)-induced contractions were reduced by verapamil and diltiazem. 5. Our results show that Mn2+ and Zn2+ behave as inhibitors of sheep duodenum motility. In contrast, Ba2+ and Ca2+ stimulate motility. It is suggested that Ba2+ can penetrate the cells through voltage-dependent Ca2+ channels and behave as a partial substitute for Ca2+. PMID:9112079

  2. 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…

  3. Distinct state anxiety after predictable and unpredictable fear training in mice.

    PubMed

    Seidenbecher, Thomas; Remmes, Jasmin; Daldrup, Thiemo; Lesting, Jörg; Pape, Hans-Christian

    2016-05-01

    Sustained fear paradigms in rodents have been developed to monitor states of anxious apprehension and to model situations in patients suffering from long-lasting anxiety disorders. A recent report describes a fear conditioning paradigm, allowing distinction between phasic and sustained states of conditioned fear in non-restrained mice. However, so far no prospective studies have yet been conducted to elucidate whether induction of phasic or sustained fear can affect states of anxiety. Here, we used CS (conditioned stimulus) and US (unconditioned stimulus) pairing with predictable and unpredictable timing to induce phasic and sustained fear in mice. State anxiety during various fear response components was assessed using the elevated plus-maze test. Training with unpredictable CS-US timing resulted in CS-evoked sustained components of fear (freezing), while predictable CS-US timing resulted in rapid decline. Data suggested the influence of training procedure on state anxiety which is dependent on progression of conditioned fear during fear memory retrieval. Animals trained with unpredictable CS-US timing showed an unchanged high anxiety state throughout behavioral observation. In contrast, mice trained with predictable CS-US timing showed anxiolytic-like behavior 3min after CS onset, which was accompanied by a fast decline of the fear conditioned response (freezing). Further systematic studies are needed to validate the phasic/sustained fear model in rodents as translational model for anxiety disorders in humans. PMID:26876138

  4. 40 CFR 761.1 - Applicability.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ..., on a weight-per-volume basis (e.g., milligrams per liter) if the density of the liquid is also.../100 cm2. (4) PCBs can be found in liquid, non-liquid and multi-phasic (combinations of liquid and non-liquid) forms. A person should use the following criteria to determine PCB concentrations to...

  5. 40 CFR 761.1 - Applicability.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ..., on a weight-per-volume basis (e.g., milligrams per liter) if the density of the liquid is also... µg/100 cm2. (4) PCBs can be found in liquid, non-liquid and multi-phasic (combinations of liquid and non-liquid) forms. A person should use the following criteria to determine PCB concentrations...

  6. 40 CFR 761.1 - Applicability.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... concentrations shall be determined on a weight-per-weight basis (e.g., milligrams per kilogram), or for liquids, on a weight-per-volume basis (e.g., milligrams per liter) if the density of the liquid is also... µg/100 cm2. (4) PCBs can be found in liquid, non-liquid and multi-phasic (combinations of liquid...

  7. 40 CFR 761.1 - Applicability.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... concentrations shall be determined on a weight-per-weight basis (e.g., milligrams per kilogram), or for liquids, on a weight-per-volume basis (e.g., milligrams per liter) if the density of the liquid is also... µg/100 cm2. (4) PCBs can be found in liquid, non-liquid and multi-phasic (combinations of liquid...

  8. 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.

  9. 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

  10. Mathematical Model Of Nerve/Muscle Interaction

    NASA Technical Reports Server (NTRS)

    Hannaford, Blake

    1990-01-01

    Phasic Excitation/Activation (PEA) mathematical model simulates short-term nonlinear dynamics of activation and control of muscle by nerve. Includes electronic and mechanical elements. Is homeomorphic at level of its three major building blocks, which represent motoneuron, dynamics of activation of muscle, and mechanics of muscle.

  11. Characteristics of Speech Motor Development in Children.

    ERIC Educational Resources Information Center

    Ostry, David J.; And Others

    1984-01-01

    Pulsed ultrasound was used to study tongue movements in the speech of children from 3 to 11 years of age. Speech data attained were characteristic of systems that can be described by second-order differential equations. Relationships observed in these systems may indicate that speech control involves tonic and phasic muscle inputs. (Author/RH)

  12. 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

  13. Electrodermal Activity of Undersocialized Aggressive Children: A Pilot Study.

    ERIC Educational Resources Information Center

    Schmidt, Katalin; And Others

    1985-01-01

    Investigated the electrodermal activity (EDA) of a small group of prepubertal children suffering from a severe form of undersocialized aggressive conduct disorder (CD). The EDA profile of the CD children resembled that of the adult sociopath on phasic measures only. (RH)

  14. Polysomnography in the Rett syndrome.

    PubMed

    Segawa, M; Nomura, Y

    1992-05-01

    The features of sleep parameters in the Rett syndrome were compared with those in early infantile autism (EIA) and hereditary progressive dystonia with marked diurnal fluctuation (HPD). The sleep-wakefulness cycle and the tonic and phasic components of sleep were evaluated in each disorder, the former was estimated by the day-by-day plot method and the latter two by polysomnography (PSG) following our method. Abnormalities of the sleep-wakefulness cycle were observed in the Rett syndrome and EIA, but in the latter these abnormalities became inapparent with age and improved markedly by correcting the environmental condition and completely by 5-hydroxytriptophan. The latter, if treated early, was followed by improvement of behavior. In the Rett syndrome, however, the abnormalities continued into late childhood to adolescence. In HPD, PSG abnormalities were restricted to the phasic component, which improved completely after levodopa in accordance with the clinical improvement. On the other hand, in the Rett syndrome as well as in EIA both the phasic and tonic components were involved and also the leakage of the components of REM stage into NREM stage was observed. In the Rett syndrome, these abnormalities aggravated with age, with disturbances in % sleep stage, nocturnal variation of tonic and phasic components of sleep and REM-NREM cycles, while in EIA the results of PSGs revealed no such progressions but showed an increase in twitch movement and a lack of normal increase in the number of REMs occurring in short intervals.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:1626634

  15. 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...

  16. 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...

  17. 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...

  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, 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...

  20. Local regulation of postprandial motor responses in ileal pouches

    PubMed Central

    Mularczyk, A; Contessini-Avesan..., E; Cesana, B; Bianchi, P; Basilisco, G

    1999-01-01

    BACKGROUND—Local mechanisms are involved in the postprandial regulation of ileal tone in healthy subjects, but whether these mechanisms affect the postprandial tonic response of ileal pouches has not yet been investigated.
AIMS—To study the effect of a meal on pouch tone and phasic motor activity in patients with gut continuity or ileostomy and, in the latter group, the effect of a pouch perfusion with chyme or saline.
PATIENTS—Twenty patients with ileal pouches: 10 with gut continuity and 10 with ileostomy.
METHODS—Pouch tone and the frequency of phasic volume events were recorded with a barostat under fasting and postprandial conditions and after perfusion of the isolated pouch with chyme or saline.
RESULTS—The meal increased pouch tone and the frequency of phasic volume events in the patients with gut continuity, but not in those with ileostomy. Pouch perfusion with chyme induced a greater increase in pouch tone than saline.
CONCLUSIONS—The meal stimulated pouch tone and phasic motor activity. These effects were at least partially related to local pouch stimulation by intraluminal contents.


Keywords: ileal pouches; postprandial motor responses; ileal tone; ileostomy; motor activity; barostat PMID:10486368

  1. 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

  2. Inhibitory effects of salviae miltiorrhizae radix (danshen) and puerariae lobatae radix (gegen) in carbachol-induced rat detrusor smooth muscle contractility

    PubMed Central

    Liang, Willmann; Teong, Ivy Wen Jia; Koon, Johnny Chi Man; Lau, Clara Bik San; Fung, Kwok Pui; Leung, Ping Chung

    2012-01-01

    Both danshen (D) and gegen (G) have proven relaxant effects on vascular smooth muscle, thus their potential bladder inhibitory effects have impending interests in urology. The aim of this study was to demonstrate the novel effects of D and G on detrusor smooth muscle contractility. Urothelium-intact (+UE) and urothelium-denuded (-UE) detrusor strips were isolated from the rat. Isometric tension was measured using a myograph system. Carbachol (CCh) was used to pre-contract the detrusor strips prior to stepwise relaxation by adding extracts of D, G, and a DG (7:3) formulation. Tonic relaxation level and phasic contractile activity under the herbal treatments were analyzed. There was no difference in the herbal effects between +UE and -UE strips. D alone induced a much smaller relaxation than G alone or DG. G alone also suppressed phasic amplitude but not phasic frequency while DG suppressed both parameters. D and G acted synergistically to yield the observed effects on detrusor smooth muscle. The findings showed that the DG formulation were able to relax the detrusor as well as suppress phasic contractions, both actions important in maintaining normal bladder filling and urine storage processes. Hence DG may have new application in the management of bladder disorders. PMID:22461955

  3. Inhibitory effects of salviae miltiorrhizae radix (danshen) and puerariae lobatae radix (gegen) in carbachol-induced rat detrusor smooth muscle contractility.

    PubMed

    Liang, Willmann; Teong, Ivy Wen Jia; Koon, Johnny Chi Man; Lau, Clara Bik San; Fung, Kwok Pui; Leung, Ping Chung

    2012-01-01

    Both danshen (D) and gegen (G) have proven relaxant effects on vascular smooth muscle, thus their potential bladder inhibitory effects have impending interests in urology. The aim of this study was to demonstrate the novel effects of D and G on detrusor smooth muscle contractility. Urothelium-intact (+UE) and urothelium-denuded (-UE) detrusor strips were isolated from the rat. Isometric tension was measured using a myograph system. Carbachol (CCh) was used to pre-contract the detrusor strips prior to stepwise relaxation by adding extracts of D, G, and a DG (7:3) formulation. Tonic relaxation level and phasic contractile activity under the herbal treatments were analyzed. There was no difference in the herbal effects between +UE and -UE strips. D alone induced a much smaller relaxation than G alone or DG. G alone also suppressed phasic amplitude but not phasic frequency while DG suppressed both parameters. D and G acted synergistically to yield the observed effects on detrusor smooth muscle. The findings showed that the DG formulation were able to relax the detrusor as well as suppress phasic contractions, both actions important in maintaining normal bladder filling and urine storage processes. Hence DG may have new application in the management of bladder disorders. PMID:22461955

  4. [Effect of phenyl derivative of gamma-aminobutyric acid phenybut on autorhythmic contractile activity of the portal vein].

    PubMed

    Ogluzdina, M V; Barabanova, V V; Berestovitskaia, V M; Usik, N V

    1998-01-01

    The phenyl derivative of the GABA phenybute exerts a direct regulating effect upon phasic and tonic components of the v.cava autorhythmical contractile activity in Wistar rats in media with an altered calcium contents, whereas no such effect occurred in hyper-potassium solution or against the background of verapamil blockade of the potential-dependent calcium channels. PMID:9612864

  5. 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…

  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. SITE PROGRAM EVALUATION OF INNOVATIVE ACID MINE DRAINAGE TREATMENT TECHNOLOGIES AT THE LEVIATHAN MINE SITE, CA

    EPA Science Inventory

    The EPA SITE Program is conducting a detailed sampling and evaluation of several innovative acid mine drainage treatment technologies at the Leviathan Mine Superfund site in California. Technologies include BiPhasic Lime Treatment Plant, an alkaline lagoon, and an innovative bio...

  8. 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…

  9. 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…

  10. 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…

  11. 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

  12. Trafficking of the Follitropin Receptor

    PubMed Central

    Ulloa-Aguirre, Alfredo; Dias, James A.; Bousfield, George; Huhtaniemi, Ilpo; Reiter, Eric

    2015-01-01

    The follitropin or follicle-stimulating hormone receptor (FSHR) belongs to a highly conserved subfamily of the G protein-coupled receptor (GPCR) superfamily and is mainly expressed in specific cells in the gonads. As any other GPCR, the newly synthesized FSHR has to be correctly folded and processed in order to traffic to the cell surface plasma membrane and interact with its cognate ligand. In this chapter, we describe in detail the conditions and procedures used to study outward trafficking of the FSHR from the endoplasmic reticulum to the plasma membrane. We also describe some methods to analyze phosphorylation, β-arrestin recruitment, internalization, and recycling of this particular receptor, which have proved useful in our hands for dissecting its downward trafficking and fate following agonist stimulation. PMID:23351732

  13. AZA Wildlife Contraception Center programme for wild felids and canids.

    PubMed

    Asa, C; Boutelle, S; Bauman, K

    2012-12-01

    North American zoos began using melengestrol acetate (MGA) implants to control reproduction in wild felids in the mid-1970s. Research linking MGA and other progestin-based contraceptives to uterine and mammary pathology in canids as well as felids resulted in a shift to GnRH agonist implants (Suprelorin(®): deslorelin, Peptech Animal Health, Australia). However, a recent study revealed an association between Suprelorin(®) and uterine pathology in canids, but that pathology was not found in canids treated with oral megestrol acetate (MA) for 2 weeks around the time of implant insertion to prevent the initial agonist stimulation phase. Thus, the AZA Wildlife Contraception Center (WCC) currently recommends Suprelorin(®) plus the 2-week MA regimen for wild canids and felids. WCC research is now focusing on factors affecting Suprelorin(®) reversibility. PMID:23279543

  14. 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.

  15. Tumorigenesis induced by the HHV8-encoded chemokine receptor requires ligand modulation of high constitutive activity.

    PubMed

    Holst, P J; Rosenkilde, M M; Manfra, D; Chen, S C; Wiekowski, M T; Holst, B; Cifire, F; Lipp, M; Schwartz, T W; Lira, S A

    2001-12-01

    ORF74 (or KSHV-vGPCR) is a highly constitutively active G protein-coupled receptor encoded by HHV8 that is regulated both positively and negatively by endogenous chemokines. When expressed in transgenic mice, this chemokine receptor induces an angioproliferative disease closely resembling Kaposi sarcoma (KS). Here we demonstrate that several lines of mice carrying mutated receptors deficient in either constitutive activity or chemokine regulation fail to develop KS-like disease. In addition, animals expressing a receptor that preserves chemokine binding and constitutive activity but that does not respond to agonist stimulation have a much lower incidence of angiogenic lesions and tumors. These results indicate that induction of the KS-like disease in transgenic mice by ORF74 requires not only high constitutive signaling activity but also modulation of this activity by endogenous chemokines. PMID:11748262

  16. Tumorigenesis induced by the HHV8-encoded chemokine receptor requires ligand modulation of high constitutive activity

    PubMed Central

    Holst, Peter J.; Rosenkilde, Mette M.; Manfra, Denise; Chen, Shu-Cheng; Wiekowski, Maria T.; Holst, Birgitte; Cifire, Felix; Lipp, Martin; Schwartz, Thue W.; Lira, Sergio A.

    2001-01-01

    ORF74 (or KSHV-vGPCR) is a highly constitutively active G protein–coupled receptor encoded by HHV8 that is regulated both positively and negatively by endogenous chemokines. When expressed in transgenic mice, this chemokine receptor induces an angioproliferative disease closely resembling Kaposi sarcoma (KS). Here we demonstrate that several lines of mice carrying mutated receptors deficient in either constitutive activity or chemokine regulation fail to develop KS-like disease. In addition, animals expressing a receptor that preserves chemokine binding and constitutive activity but that does not respond to agonist stimulation have a much lower incidence of angiogenic lesions and tumors. These results indicate that induction of the KS-like disease in transgenic mice by ORF74 requires not only high constitutive signaling activity but also modulation of this activity by endogenous chemokines. PMID:11748262

  17. Cross-linking of F508-CFTR promotes its trafficking to the plasma membrane

    PubMed Central

    Bernard, Karen

    2010-01-01

    CFTR is a cAMP-activated chloride channel responsible for agonist stimulated chloride and fluid transport across epithelial surfaces.1 Mutations in the CFTR gene lead to cystic fibrosis (CF) which affects the function of secretory organs like the intestine, the pancreas, the airways and the sweat glands. Most of the morbidity and mortality in CF has been linked to a decrease in airway function.2 The ΔF508 mutation is the most common CF-related mutation in the Caucasian population and represents 90% of CF alleles. Homozygote carriers of this mutation present with a severe CF phenotype.3 The ΔF508 mutation causes misfolding of the nascent CFTR polypeptide, which leads to inefficient export from the endoplasmic reticulum (ER) and rapid degradation by the proteasome.4 PMID:20581470

  18. Cholinergic agonists and interleukin 1 regulate processing and secretion of the Alzheimer beta/A4 amyloid protein precursor.

    PubMed Central

    Buxbaum, J D; Oishi, M; Chen, H I; Pinkas-Kramarski, R; Jaffe, E A; Gandy, S E; Greengard, P

    1992-01-01

    Activation of protein kinase C by phorbol esters is known to accelerate the processing and secretion of the beta/A4 amyloid protein precursor. We have now examined various first messengers that increase protein kinase C activity of target cells for their ability to affect beta/A4 amyloid protein precursor metabolism. Acetylcholine and interleukin 1, which are altered in Alzheimer disease, were shown to increase processing of the beta/A4 amyloid protein precursor via the secretory cleavage pathway. Cholinergic agonists stimulated secretion in human glioma and neuroblastoma cells as well as in PC12 cells transfected with the M1 receptor, while interleukin 1 stimulated secretion in human endothelial and glioma cells. Images PMID:1359534

  19. 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.

  20. Discovery of DS-1558: A Potent and Orally Bioavailable GPR40 Agonist

    PubMed Central

    2015-01-01

    GPR40 is a G protein-coupled receptor that is predominantly expressed in pancreatic β-cells. GPR40 agonists stimulate insulin secretion in the presence of high glucose concentration. On the basis of this mechanism, GPR40 agonists are possible novel insulin secretagogues with reduced or no risk of hypoglycemia. The improvement of in vitro activity and metabolic stability of compound 1 led to the discovery of 13, (3S)-3-ethoxy-3-(4-{[(1R)-4-(trifluoromethyl)-2,3-dihydro-1H-inden-1-yl]oxy}phenyl)propanoic acid, as a potent and orally available GPR40 agonist. Compound 13 (DS-1558) was found to have potent glucose lowering effects during an oral glucose tolerance test in ZDF rats. PMID:25815144

  1. 15d-prostaglandin J2 enhancement of nerve growth factor-induced neurite outgrowth is blocked by the chemoattractant receptor- homologous molecule expressed on T-helper type 2 cells (CRTH2) antagonist CAY10471 in PC12 cells.

    PubMed

    Hatanaka, Michiyoshi; Shibata, Norihiro; Shintani, Norihito; Haba, Ryota; Hayata, Atsuko; Hashimoto, Hitoshi; Baba, Akemichi

    2010-01-01

    The chemoattractant receptor-homologous molecule expressed on T-helper type 2 cells (CRTH2) is the most recently identified prostaglandin (PG) receptor for both PGD(2) and 15-deoxy-Delta(12,14)-PGJ(2) (15d-PGJ(2)). We examined the mechanism by which 15d-PGJ(2) enhances nerve growth factor (NGF)-induced neurite outgrowth in PC12 cells. CAY10471 (CRTH2 antagonist) inhibited both the neurite-promotion and p38 mitogen-activated protein (MAP) kinase phosphorylation induced by 15d-PGJ(2). In contrast, 13,14-dihydro-15-keto-PGD(2 )(DK-PGD(2)) (selective CRTH2 agonist) stimulated its phosphorylation but failed to produce neurite-promoting effects. These suggest, for the first time, the action of 15d-PGJ(2) is mediated by CRTH2, although the CRTH2 activation alone is insufficient for the underlying action. PMID:20424389

  2. Epithelial P2X purinergic receptor channel expression and function

    PubMed Central

    Taylor, Amanda L.; Schwiebert, Lisa M.; Smith, Jeffrey J.; King, Chris; Jones, Julie R.; Sorscher, Eric J.; Schwiebert, Erik M.

    1999-01-01

    P2X purinergic receptor (P2XR) channels bind ATP and mediate Ca2+ influx — 2 signals that stimulate secretory Cl– transport across epithelia. We tested the hypotheses that P2XR channels are expressed by epithelia and that P2XRs transduce extracellular ATP signals into stimulation of Cl– transport across epithelia. Electrophysiological data and mRNA analysis of human and mouse pulmonary epithelia and other epithelial cells indicate that multiple P2XRs are broadly expressed in these tissues and that they are active on both apical and basolateral surfaces. Because P2X-selective agonists bind multiple P2XR subtypes, and because P2X agonists stimulate Cl– transport across nasal mucosa of cystic fibrosis (CF) patients as well as across non-CF nasal mucosa, P2XRs may provide novel targets for extracellular nucleotide therapy of CF. PMID:10510328

  3. Revealing the Functional Neuroanatomy of Intrinsic Alertness Using fMRI: Methodological Peculiarities

    PubMed Central

    Clemens, Benjamin; Zvyagintsev, Mikhail; Sack, Alexander; Heinecke, Armin; Willmes, Klaus; Sturm, Walter

    2011-01-01

    Clinical observations and neuroimaging data revealed a right-hemisphere fronto-parietal-thalamic-brainstem network for intrinsic alertness, and additional left fronto-parietal activity during phasic alertness. The primary objective of this fMRI study was to map the functional neuroanatomy of intrinsic alertness as precisely as possible in healthy participants, using a novel assessment paradigm already employed in clinical settings. Both the paradigm and the experimental design were optimized to specifically assess intrinsic alertness, while at the same time controlling for sensory-motor processing. The present results suggest that the processing of intrinsic alertness is accompanied by increased activity within the brainstem, thalamus, anterior cingulate gyrus, right insula, and right parietal cortex. Additionally, we found increased activation in the left hemisphere around the middle frontal gyrus (BA 9), the insula, the supplementary motor area, and the cerebellum. Our results further suggest that rather minute aspects of the experimental design may induce aspects of phasic alertness, which in turn might lead to additional brain activation in left-frontal areas not normally involved in intrinsic alertness. Accordingly, left BA 9 activation may be related to co-activation of the phasic alertness network due to the switch between rest and task conditions functioning as an external warning cue triggering the phasic alertness network. Furthermore, activation of the intrinsic alertness network during fixation blocks due to enhanced expectancy shortly before the switch to the task block might, when subtracted from the task block, lead to diminished activation in the typical right hemisphere intrinsic alertness network. Thus, we cautiously suggest that – as a methodological artifact – left frontal activations might show up due to phasic alertness involvement and intrinsic alertness activations might be weakened due to contrasting with fixation blocks, when assessing

  4. 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

  5. Differential modulation of reinforcement learning by D2 dopamine and NMDA glutamate receptor antagonism.

    PubMed

    Jocham, Gerhard; Klein, Tilmann A; Ullsperger, Markus

    2014-09-24

    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

  6. Eye Movements and Abducens Motoneuron Behavior after Cholinergic Activation of the Nucleus Reticularis Pontis Caudalis

    PubMed Central

    Márquez-Ruiz, Javier; Escudero, Miguel

    2010-01-01

    Study Objectives: The aim of this work was to characterize eye movements and abducens (ABD) motoneuron behavior after cholinergic activation of the nucleus reticularis pontis caudalis (NRPC). Methods: Six female adult cats were prepared for chronic recording of eye movements (using the scleral search-coil technique), electroencephalography, electromyography, ponto-geniculo-occipital (PGO) waves in the lateral geniculate nucleus, and ABD motoneuron activities after microinjections of the cholinergic agonist carbachol into the NRPC. Results: Unilateral microinjections of carbachol in the NRPC induced tonic and phasic phenomena in the oculomotor system. Tonic effects consisted of ipsiversive rotation to the injected side, convergence, and downward rotation of the eyes. Phasic effects consisted of bursts of rhythmic rapid eye movements directed contralaterally to the injected side along with PGO-like waves in the lateral geniculate and ABD nuclei. Although tonic effects were dependent on the level of drowsiness, phasic effects were always present and appeared along with normal saccades when the animal was vigilant. ABD motoneurons showed phasic activities associated with ABD PGO-like waves during bursts of rapid eye movements, and tonic and phasic activities related to eye position and velocity during alertness. Conclusion The cholinergic activation of the NRPC induces oculomotor phenomena that are somewhat similar to those described during REM sleep. A precise comparison of the dynamics and timing of the eye movements further suggests that a temporal organization of both NRPCs is needed to reproduce the complexity of the oculomotor behavior during REM sleep. Citation: Márquez-Ruiz J; Escudero M. Eye movements and abducens motoneuron behavior after cholinergic activation of the nucleus reticularis pontis caudalis. SLEEP 2010;33(11):1517-1527. PMID:21102994

  7. Constitutively active PKA regulates neuronal acetylcholine release and contractility of guinea pig urinary bladder smooth muscle.

    PubMed

    Xin, Wenkuan; Li, Ning; Fernandes, Vitor S; Petkov, Georgi V

    2016-06-01

    Autonomic and somatic motor neurons that innervate the urinary bladder and urethra control the highly coordinated functions of the lower urinary tract, the storage, and the emptying of urine. ACh is the primary excitatory neurotransmitter in the bladder. Here, we aimed to determine whether PKA regulates neuronal ACh release and related nerve-evoked detrusor smooth muscle (DSM) contractions in the guinea pig urinary bladder. Isometric DSM tension recordings were used to measure spontaneous phasic and electrical field stimulation (EFS)- and carbachol-induced DSM contractions with a combination of pharmacological tools. The colorimetric method was used to measure ACh released by the parasympathetic nerves in DSM isolated strips. The pharmacological inhibition of PKA with H-89 (10 μM) increased the spontaneous phasic contractions, whereas it attenuated the EFS-induced DSM contractions. Intriguingly, H-89 (10 μM) attenuated the (primary) cholinergic component, whereas it simultaneously increased the (secondary) purinergic component of the nerve-evoked contractions in DSM isolated strips. The acetylcholinesterase inhibitor, eserine (10 μM), increased EFS-induced DSM contractions, and the subsequent addition of H-89 attenuated the contractions. H-89 (10 μM) significantly increased DSM phasic contractions induced by the cholinergic agonist carbachol. The inhibition of PKA decreased the neuronal release of ACh in DSM tissues. This study revealed that PKA-mediated signaling pathways differentially regulate nerve-evoked and spontaneous phasic contractions of guinea pig DSM. Constitutively active PKA in the bladder nerves controls synaptic ACh release, thus regulating the nerve-evoked DSM contractions, whereas PKA in DSM cells controls the spontaneous phasic contractility. PMID:27029424

  8. The physiological basis of heterochromatic flicker photometry demonstrated in the ganglion cells of the macaque retina.

    PubMed Central

    Lee, B B; Martin, P R; Valberg, A

    1988-01-01

    1. Heterochromatic flicker photometry is a way of measuring the spectral sensitivity of the human eye. Two lights of different colour are sinusoidally alternated at, typically, 10-20 Hz, and their relative intensities adjusted by the observer until the sensation of flicker is minimized. This technique has been used to define the human photopic luminosity, or V lambda, function on which photometry is based. 2. We have studied the responses of macaque retinal ganglion cells using this stimulus paradigm. The responses of the phasic ganglion cells go through a minimum at relative radiances very similar to that predicted from the V lambda function. At this point, defined as equal luminance, an abrupt change in response phase was observed. A small residual response at twice the flicker frequency was apparent under some conditions. 3. The spectral sensitivity of parafoveal phasic cells measured in this way corresponded very closely to that of human observers minimizing flicker on the same apparatus. 4. Minima in phasic cell activity were independent of flicker frequency, as is the case in the psychophysical task. 5. The response minima of phasic cells obey the laws of additivity and transitivity which are important characteristics of heterochromatic flicker photometry. 6. As the relative intensities of the lights were altered responses of tonic, spectrally opponent cells usually underwent a gradual phase change with vigorous responses at equal luminance. The responses of tonic cells treated individually or as a population could not be related to the V lambda function in any meaningful way. 7. We conclude that the phasic, magnocellular cell system of the primate visual pathway underlies performance in the psychophysical task of heterochromatic flicker photometry. It is likely that other tasks in which spectral sensitivity conforms to the V lambda function also rely on this cell system. PMID:3253435

  9. 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

  10. Nanoscale analysis reveals agonist-sensitive and heterogeneous pools of phosphatidylinositol 4-phosphate in the plasma membrane.

    PubMed

    Yoshida, Akane; Shigekuni, Mikiko; Tanabe, Kenji; Fujita, Akikazu

    2016-06-01

    Phosphatidylinositol 4-phosphate [PtdIns(4)P] is the immediate precursor of phosphatidylinositol 4,5-bisphosphate [PtdIns(4,5)P2], which is localized to the cytoplasmic leaflet of the plasma membrane and has been reported to possess multiple cell biological functions. Direct evidence showing the distribution of PtdIns(4)P pools at a nanoscale when the plasma membrane PtdIns(4,5)P2 is hydrolyzed by agonist stimulation is lacking. To analyze the distribution of PtdIns(4)P at a nanoscale, we employed an electron microscopy technique that specifically labels PtdIns(4)P on the freeze-fracture replica of the plasma membrane. This method minimizes the possibility of artificial perturbation, because molecules in the membrane are physically immobilized in situ. Using this technique, we observed no PtdIns(4)P in the caveolae of normal cultured human fibroblasts, although PtdIns(4,5)P2 has been shown to be highly concentrated in them in our previous report. When cells were stimulated with angiotensin II, the level of PtdIns(4)P in the undifferentiated membrane transiently decreased to 64.3% at 10 s, began to increase at 30 s and largely increased to 341.9% at 40 s, and then returned to the initial level at 130 s after the stimulation. Interestingly, PtdIns(4)P localized at the caveolae at 70 and 130 s after the stimulation. These results suggest that the level of the PtdIns(4)P pool in the plasma membrane is sensitive and the distribution of PtdIns(4)P dramatically changes by agonist stimulation, and there are active sites of production or replenishment of PtdIns(4)P at undifferentiated membrane and caveolar areas. PMID:26972044

  11. Cucurbitacins attenuate microglial activation and protect from neuroinflammatory injury through Nrf2/ARE activation and STAT/NF-κB inhibition.

    PubMed

    Park, Sun Young; Kim, Young Hun; Park, Geuntae

    2015-11-16

    Emerging evidence suggests that neuroinflammatory responses are involved in the neuronal injury. Neuroinflammatory response is mediated by cellular components such as microglia and molecular components, including nitric oxide, prostaglandins and inflammatory cytokines, activation of complement proteins etc. Cucurbitacins is a class of highly oxidized tetracyclic triterpenoids isolated mainly from Cucurbitaceae but also from other plan families and has been reported to have pharmacological activities. The present study aimed to investigate the anti-neuroinflammatory effects of Cucurbitacins on TLR 2/4 agonists (amyloid-β, LTA, and LPS)-induced neuroinflammatory response in microglia and the underlying mechanism for Nrf2/ARE pathways. Results indicates that pretreatment with Cucurbitacins significantly reduced the pro-inflammatory cytokine (TNF-α, IL-1β and IL-6) and attenuated iNOS and COX-2 expression in TLR 2/4 agonists-stimulated microglia. In addition, Cucurbitacins inhibited JNK and p38 MAPKs activation and attenuated JAK-STAT and NF-κB activation in TLR 2/4 agonists-stimulated microglia. Next, we evaluate the potential involvement of Cucurbitacins in the activation of Nrf2/ARE signaling pathways and phase II detoxification enzymes activity. Results indicate that Cucurbitacins markedly promoted the activation of Nrf-2/ARE pathway-related downstream factors including NQO-1 and HO-1. Furthermore, anti-neuroinflammatory effects of Cucurbitacins are attenuated in the knockdown of Nrf2, HO-1 and NQO-1 respectively. Cucurbitacins also has neuroprotective effect against microglia over-activation related neuronal damage. This study demonstrates that Cucurbitacins is potent activator of the Nrf2/ARE pathway and is therapeutically relevant not only to neuroinflammatory responses of microglia but also neuroinflammation mediated neuronal injury. PMID:26472707

  12. 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

  13. Arrestins 2 and 3 differentially regulate ETA and P2Y2 receptor-mediated cell signaling and migration in arterial smooth muscle

    PubMed Central

    Morris, Gavin E.; Nelson, Carl P.; Brighton, Paul J.; Standen, Nicholas B.; Challiss, R. A. John

    2012-01-01

    Overstimulation of endothelin type A (ETA) and nucleotide (P2Y) Gαq-coupled receptors in vascular smooth muscle causes vasoconstriction, hypertension, and, eventually, hypertrophy and vascular occlusion. G protein-coupled receptor kinases (GRKs) and arrestin proteins are sequentially recruited by agonist-occupied Gαq-coupled receptors to terminate phospholipase C signaling, preventing prolonged/inappropriate contractile signaling. However, these proteins also play roles in the regulation of several mitogen-activated protein kinase (MAPK) signaling cascades known to be essential for vascular remodeling. Here we investigated whether different arrestin isoforms regulate endothelin and nucleotide receptor MAPK signaling in rat aortic smooth muscle cells (ASMCs). When intracellular Ca2+ levels were assessed in isolated ASMCs loaded with Ca2+-sensitive dyes, P2Y2 and ETA receptor desensitization was attenuated by selective small-interfering (si)RNA-mediated depletion of G protein-coupled receptor kinase 2 (GRK2). Using similar siRNA techniques, knockdown of arrestin2 prevented P2Y2 receptor desensitization and enhanced and prolonged p38 and ERK MAPK signals, while arrestin3 depletion was ineffective. Conversely, arrestin3 knockdown prevented ETA receptor desensitization and attenuated ET1-stimulated p38 and ERK signals, while arrestin2 depletion had no effect. Using Transwell assays to assess agonist-stimulated ASMC migration, we found that UTP-stimulated migration was markedly attenuated following arrestin2 depletion, while ET1-stimulated migration was attenuated following knockdown of either arrestin. These data highlight a differential arrestin-dependent regulation of ETA and P2Y2 receptor-stimulated MAPK signaling. GRK2 and arrestin expression are essential for agonist-stimulated ASMC migration, which, as a key process in vascular remodeling, highlights the potential roles of GRK2 and arrestin proteins in the progression of vascular disease. PMID:22159081

  14. 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

  15. 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

  16. Arrestins 2 and 3 differentially regulate ETA and P2Y2 receptor-mediated cell signaling and migration in arterial smooth muscle.

    PubMed

    Morris, Gavin E; Nelson, Carl P; Brighton, Paul J; Standen, Nicholas B; Challiss, R A John; Willets, Jonathon M

    2012-03-01

    Overstimulation of endothelin type A (ET(A)) and nucleotide (P2Y) Gα(q)-coupled receptors in vascular smooth muscle causes vasoconstriction, hypertension, and, eventually, hypertrophy and vascular occlusion. G protein-coupled receptor kinases (GRKs) and arrestin proteins are sequentially recruited by agonist-occupied Gα(q)-coupled receptors to terminate phospholipase C signaling, preventing prolonged/inappropriate contractile signaling. However, these proteins also play roles in the regulation of several mitogen-activated protein kinase (MAPK) signaling cascades known to be essential for vascular remodeling. Here we investigated whether different arrestin isoforms regulate endothelin and nucleotide receptor MAPK signaling in rat aortic smooth muscle cells (ASMCs). When intracellular Ca(2+) levels were assessed in isolated ASMCs loaded with Ca(2+)-sensitive dyes, P2Y(2) and ET(A) receptor desensitization was attenuated by selective small-interfering (si)RNA-mediated depletion of G protein-coupled receptor kinase 2 (GRK2). Using similar siRNA techniques, knockdown of arrestin2 prevented P2Y(2) receptor desensitization and enhanced and prolonged p38 and ERK MAPK signals, while arrestin3 depletion was ineffective. Conversely, arrestin3 knockdown prevented ET(A) receptor desensitization and attenuated ET1-stimulated p38 and ERK signals, while arrestin2 depletion had no effect. Using Transwell assays to assess agonist-stimulated ASMC migration, we found that UTP-stimulated migration was markedly attenuated following arrestin2 depletion, while ET1-stimulated migration was attenuated following knockdown of either arrestin. These data highlight a differential arrestin-dependent regulation of ET(A) and P2Y(2) receptor-stimulated MAPK signaling. GRK2 and arrestin expression are essential for agonist-stimulated ASMC migration, which, as a key process in vascular remodeling, highlights the potential roles of GRK2 and arrestin proteins in the progression of vascular disease

  17. GPR40 (FFAR1) – Combined Gs and Gq signaling in vitro is associated with robust incretin secretagogue action ex vivo and in vivo

    PubMed Central

    Hauge, Maria; Vestmar, Marie A.; Husted, Anna S.; Ekberg, Jeppe P.; Wright, Michael J.; Di Salvo, Jerry; Weinglass, Adam B.; Engelstoft, Maja S.; Madsen, Andreas N.; Lückmann, Michael; Miller, Michael W.; Trujillo, Maria E.; Frimurer, Thomas M.; Holst, Birgitte; Howard, Andrew D.; Schwartz, Thue W.

    2014-01-01

    Objectives GPR40 (FFAR1), a clinically proven anti-diabetes target, is a Gq-coupled receptor for long chain fatty acids (LCFA) stimulating insulin secretion directly and mediating a major part of the dietary triglyceride-induced secretion of the incretins GLP-1 and GIP. In phase-II studies the GPR40 agonist TAK-875 decreased blood glucose but surprisingly without stimulating incretins. Methods and results Here we find that GPR40 can signal through not only Gq and IP3 but also Gs and cAMP when stimulated with certain agonists such as AM-1638 and AM-5262 in contrast to the endogenous LCFA ligands and agonists such as TAK-875 and AM-837, which only signal through Gq. In competition binding against [3H]AM-1638 and [3H]L358 the Gq + Gs and the Gq-only agonists either competed for or showed positive cooperativity by increasing the binding of the two different radio-ligands, in opposite ways. Nevertheless, both the Gq-only and the Gq + Gs agonists all docked surprisingly well into the binding site for TAK-875 in the X-ray structure of GPR40. In murine intestinal primary cell-cultures the endogenous LCFAs and the Gq-only agonists stimulated GLP-1 secretion with rather poor efficacy as compared with the high efficacy Gq + Gs GPR40 agonists and a prototype GPR119 agonist. Similarly, in fasting both male and female mice the Gq + Gs agonists showed significantly higher efficacy than the Gq-only agonists in respect of increasing plasma GLP-1 and plasma GIP in a GPR40-dependent manner. Conclusions It is concluded that stimulation of GPR40 by endogenous LCFAs or by Gq-only synthetic agonists result in a rather limited incretin response, whereas Gq + Gs GPR40 agonists stimulate incretin secretion robustly. PMID:25685685

  18. Mucociliary clearance and submucosal gland secretion in the ex vivo ferret trachea.

    PubMed

    Jeong, Jin Hyeok; Joo, Nam Soo; Hwang, Peter H; Wine, Jeffrey J

    2014-07-01

    In many species submucosal glands are an important source of tracheal mucus, but the extent to which mucociliary clearance (MCC) depends on gland secretion is unknown. To explore this relationship, we measured basal and agonist-stimulated MCC velocities in ex vivo tracheas from adult ferrets and compared the velocities with previously measured rates of ferret glandular mucus secretion (Cho HJ, Joo NS, Wine JJ. Am J Physiol Lung Cell Mol Physiol 299: L124-L136, 2010). Stimulated MCC velocities (mm/min, means ± SE for 10- to 35-min period poststimulation) were as follows: 1 μM carbachol: 19.1 ± 3.3 > 10 μM phenylephrine: 15.3 ± 2.4 ≈ 10 μM isoproterenol: 15.0 ± 1.9 ≈ 10 μM forskolin: 14.6 ± 3.1 > 1 μM vasoactive intestinal peptide (VIP): 10.2 ± 2.2 > basal (t15): 1.8 ± 0.3; n = 5-10 for each condition. Synergistic stimulation of MCC was observed between low concentrations of carbachol (100 nM) and isoproterenol (300 nM). Bumetanide inhibited carbachol-stimulated MCC by ~70% and abolished the increase in MCC stimulated by forskolin + VIP, whereas HCO3 (-)-free solutions did not significantly inhibit MCC to either intracellular Ca(2+) concentration or intracellular cAMP concentration ([cAMP]i)-elevating agonists. Stimulation and inhibition of MCC and gland secretion differed in several respects: most importantly, elevating [cAMP]i increased MCC much more effectively than expected from its effects on gland secretion, and bumetanide almost completely inhibited [cAMP]i-stimulated MCC while it had a smaller effect on gland secretion. We conclude that changes in glandular fluid secretion are complexly related to MCC and discuss possible reasons for this. PMID:24793168

  19. 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

  20. 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

  1. [(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

  2. Platelet Activation in Ovines Undergoing Sham Surgery or Implant of the Second Generation PediaFlow™ Pediatric Ventricular Assist Device

    PubMed Central

    Johnson, Carl A.; Wearden, Peter D.; Kocyildirim, Ergin; Maul, Timothy M.; Woolley, Joshua R.; Ye, Sang-Ho; Strickler, Elise M.; Borovetz, Harvey S.; Wagner, William R.

    2011-01-01

    The PediaFlow™ pediatric ventricular assist device (VAD) is a magnetically levitated turbodynamic pump under development for circulatory support of small children with a targeted flow rate range of 0.3 - 1.5 L/min. As the design of this device is refined, ensuring high levels of blood biocompatibility is essential. In this study we characterized platelet activation during the implantation and operation of a second generation prototype of the PediaFlow VAD (PF2) and also performed a series of surgical sham studies to examine purely surgical effects on platelet activation. In addition, a newly available monoclonal antibody was characterized and shown to be capable of quantifying ovine platelet activation. The PF2 was implanted in 3 chronic ovine experiments of 16, 30, and 70 days, while surgical sham procedures were performed in 5 ovines with 30 d monitoring. Blood biocompatibility in terms of circulating activated platelets was measured by flow cytometric assays with and without exogenous agonist stimulation. Platelet activation following sham surgery returned to baseline in approximately 2 weeks. Platelets in PF2 implanted ovines returned to baseline activation levels in all three animals, and showed an ability to respond to agonist stimulation. Late term platelet activation was observed in one animal corresponding with unexpected pump stoppages related to a manufacturing defect in the percutaneous cable. The results demonstrated encouraging platelet biocompatibility for the PF2 in that basal platelet activation was achieved early in the pump implant period. Furthermore, this first characterization of the effect of a major cardiothoracic procedure on temporal ovine platelet activation provides comparative data for future cardiovascular device evaluation in the ovine model. PMID:21463346

  3. Effect of iodide on glucose oxidation and /sup 32/P incorporation into phospholipids stimulated by different agents in dog thyroid slices

    SciTech Connect

    Tseng, F.Y.; Rani, C.S.; Field, J.B.

    1989-03-01

    Since iodide (I-) inhibits TSH stimulation of cAMP formation, which mediates most of the effects of the hormone, it has been assumed that this accounts for the inhibitory action of iodide on the thyroid. However, TSH stimulation of 32P incorporation into phospholipids and stimulation of thyroid metabolism by other agonists, such as carbachol, phorbol esters, and ionophore A23187, is not cAMP mediated. The present studies examined the effect of iodide on stimulation of glucose oxidation and 32P incorporation into phospholipids by TSH and other agonists to determine if the inhibition of cAMP formation was responsible for the action of iodide. Preincubation of dog thyroid slices for 1 h with iodide (10(-4) M) inhibited TSH-, (Bu)2cAMP-, carbachol-, methylene blue-, 12-O-tetradecanoyl phorbol-13-acetate-, ionophore A23187-, prostaglandin E1-, and cholera toxin-stimulated glucose oxidation. I- also inhibited the stimulation by TSH, 12-O-tetradecanoyl phorbol-13-acetate, carbachol, and ionophore A23187 of 32P incorporation into phospholipids. The inhibition was similar whether iodide was added 2 h before or simultaneously with the agonist. I- itself sometimes stimulated basal glucose oxidation, but had no effect on basal 32P incorporation into phospholipids. The effects of iodide on basal and agonist-stimulated thyroid metabolism were blocked by methimazole (10(-3) M). When dog thyroid slices were preloaded with 32PO4 or (1-14C)glucose, the iodide inhibition of agonist stimulation disappeared, suggesting that the effect of iodide involves the transport process. In conclusion, I- inhibited stimulation of glucose oxidation and 32P incorporation into phospholipids by all agonists, indicating that the effect is independent of the cAMP system and that iodide autoregulation does not only involve this system. Oxidation and organification of iodide are necessary for the inhibition.

  4. Assessing Residents' Frozen Section Skills for Endometrial Cancer.

    PubMed

    Selove, William; Bradford, Leslie S; Liu, Yuxin

    2016-09-01

    Intraoperative frozen section (IFS) on endometrial cancer is an invaluable skill for pathologists-in-training to master. Within limited time constraints, pathologists are expected to determine tumor type, grade, and depth of myometrial invasion. During their training, pathology residents gradually gain experience in handling the majority of cases. However, significant errors can still be seen among senior level trainees. We aimed to improve training effectiveness by evaluating our trainees' performance, identifying common errors, and recommending focused curriculum. Twenty-two residents [postgraduate year (PGY)-1-PGY-4] performed 260 IFS during a 4-yr period. We compared their independent IFS diagnoses with final diagnoses. Overall resident IFS accuracy was 73%. Accuracy for tumor type and depth of myometrial invasion was 80% and 93%, respectively. Two thirds of errors were due to sampling with the rest because of interpretation. Major deficiencies lay in recognizing high-risk histologic types (serous, clear cell, sarcoma) and unconventional myometrial invasion patterns (MELF, adenoma malignum, and adenomyosis-like). Resident IFS errors would theoretically result in suboptimal staging for 32 (12%) patients and unnecessary staging for 1 (0.4%). Overall IFS performance improved as training level increased (76% accuracy for PGY-1 accompanied by PGY-5; 59% for PGY-2; 74% for PGY-3; and 86% for PGY-4). We recommend a dedicated curriculum targeting these difficult yet clinically important entities through review literature and a collection of classic cases demonstrating the diverse morphology variations. Implementing such focused training would greatly improve our trainees' competence on IFS, preparing them to handle a wide variety of cases and situations in future practice. PMID:26598984

  5. Epigenetic modulation of the protein kinase A RIIα (PRKAR2A) gene by histone deacetylases 1 and 2 in human smooth muscle cells

    PubMed Central

    Karolczak-Bayatti, Magdalena; Loughney, Andrew D; Robson, Stephen C; Europe-Finner, G Nicholas

    2011-01-01

    Abstract Recently we reported that the expression of the protein kinase A (PKA) regulatory subunit RIIα is dynamically regulated in human smooth muscle cells of the uterus. We showed that expression levels of mRNA/protein were substantially increased during pregnancy and decreased upon labour, changes that were mirrored by particulate type II PKA activity. This implied an important role for RIIα in maintaining uterine quiescence during pregnancy. Consequently the purpose of the present study was to identify potential mechanisms by which expression of the RIIα gene was regulated in this tissue. We indicate here that the three SpI-III (GC) binding domains within the proximal promoter region of the human RIIα gene may play important roles in modulating expression of the gene in human myometrial cells. We show that all three GC binding domains are involved in binding Sp1, Sp3, histone deacetylase (HDACs) 1/2 and RbAp48 transcriptional complexes. The functional significance of these binding domains was further analysed employing in vitro luciferase reporter assays with full-length/truncated RIIα promoter constructs. Importantly we show that treatment of primary human myometrial cell cultures with the general class I/II HDAC inhibitor trichostatin A results in an increase in mRNA/protein levels. Moreover the increase in mRNA levels appeared to be preceded by an increase in aH3, PolIIa, Sp3 and HDAC 2 binding to the three SpI-III (GC) binding sites within the RIIα promoter. These results enable us to provide a model whereby RIIα expression is epigenetically regulated in human myometrial smooth muscle cells by histone deacetylase(s) activity within the GC-rich proximal promoter region of the gene. PMID:19818097

  6. Expression of MIF and c-erbB-2 in endometrial cancer

    PubMed Central

    XIAO, WEI; DONG, XIUJUAN; ZHAO, HONGHUI; HAN, SHIYU; NIE, RUIXUE; ZHANG, XIAHUA; AN, RUIFANG

    2016-01-01

    The aim of the present study was to investigate the expression of c-erbB-2 and macrophage migration inhibitory factor (MIF) in endometrial cancer and to elucidate the significance of the early diagnosis and prognosis of endometrial cancer. The gene copy number of c-erbB-2 and MIF was characterized by reverse transcription quantitative polymerase chain reaction and the reactivity was assessed by immunohistochemistry in 70 patients using a polyclonal antibody, and evaluated semiquantitatively according to the percentage of cells demonstrating membranous or diffuse cytoplasmic staining. A correlation between age, tumor stage, grade, myometrial invasion and lymph node metastasis was observed. The mRNA expression of c-erbB-2 and MIF was high in endometrial carcinoma. The positive expression rate of MIF protein in normal endometrium, atypical hyperplasia and endometrial carcinoma significantly increased along with the degree of aggravation of the disease by 20 (3/15), 45 (9/20) and 70% (35/50), respectively. The positive expression of MIF and c-erbB-2 was highest in endometrial cancer and a significantly higher level of protein was observed in tumors at stage I, stage G1, with a depth of myometrial invasion <0.4 cm and no lymph node metastasis. The protein expression of c-erbB-2 in endometrial cancer was higher in tumors at the G2-3 phase, clinical stage III–IV, lymph node metastasis, and had no association with the depth of myometrial invasion and age. MIF and c-erbB-2 were correlated with the occurrence and the development of endometrial cancer, and thus can be used for the early diagnosis and prognosis of endometrial cancer. The present study laid the foundation for identifying new treatments for endometrial cancer. PMID:26985869

  7. 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

  8. 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

  9. Role of hyaluronan and hyaluronan synthase in endometrial cancer.

    PubMed

    Yabushita, Hiromitsu; Kishida, Tameko; Fusano, Kanako; Kanyama, Kouhei; Zhuo, Lisheng; Itano, Naoki; Kimata, Koji; Noguchi, Masayoshi

    2005-06-01

    The aim of this study was to determine if the immunohistochemical expression of hyaluronan synthase (HAS) and serum levels of hyaluronan correlate with the clinicopathological manifestations of endometrial carcinoma. Sera were obtained from 59 endometrial cancer patients and 22 post-menopausal healthy women. Concentration of hyaluronan in sera was measured by an inhibitory ELISA using a hyaluronan-binding protein. Tissues obtained from 59 endometrial cancer patients were immunostained by the avidin-biotin-peroxidase complex method using anti-HAS1, anti-HAS2, anti-HAS3 and anti-CD44 antibody. A section was defined as having positive expression when >50% of the tumor cells were intensely stained. The expression of HAS1 was related to the depth of myometrial invasion, histological grade and lymph-vascular space involvement, but the expression of HAS2 and HAS3 was unrelated to these parameters. CD44 expression occurred more frequently in the HAS2- or HAS3-positive groups than in the HAS2- or HAS3-negative groups, and the expression of HAS1 was unrelated to CD44 expression. Serum levels of hyaluronan were higher in the endometrial cancer group than in the healthy control group, and increased with depth of myometrial invasion, histological grade and lymph-vascular space involvement. Serum hyaluronan levels were higher in the HAS1-positive group than in the HAS1-negative group, but the expression of HAS2 and HAS3 was unrelated to serum hyaluronan levels. HAS1 expression and an increase in serum hyaluronan in endometrial cancer may be associated with disease progression through myometrial invasion and lymph-vascular space involvement. PMID:15870928

  10. 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). PMID:19776098

  11. Effect of corticotropin-releasing factor-binding protein on prostaglandin release from cultured maternal decidua and on contractile activity of human myometrium in vitro.

    PubMed

    Petraglia, F; Benedetto, C; Florio, P; D'Ambrogio, G; Genazzani, A D; Marozio, L; Vale, W

    1995-10-01

    Human placenta and uterine tissues are sites of production and local action of corticotropin-releasing factor (CRF). The recent evidence that CRF-binding protein (CRF-BP), a protein that blocks CRF-induced pituitary ACTH release, is produced by placental tissues suggested the present study to investigate the effects of CRF-BP on prostaglandin release and contractile activity of myometrial strips. Primary cultures of decidual cells were prepared using tissue collected from healthy women undergoing cesarean delivery at term. Mechanical and enzymatic cell dispersions were carried out, and experiments were performed 24-28 h after cell plating. The prostaglandin E2 (PGE2) concentration in cultured medium was measured by RIA. Myometrial strips were obtained from the upper edge of the uterine incision during elective cesarean section at term. Dissected free of connective tissue, strips were mounted in a 30-mL two-chamber organ bath containing oxygenated Tyrode's buffer (37 C) and connected to a two-channel isometric smooth muscle transducer. Cultured decidual cells collected at term significantly increased the release of PGE2 in the presence of CRF (P < 0.01). The addition of CRF-BP did not significantly modify PGE2 release, but completely reversed the effect of CRF. When human myometrial strips were incubated in the presence of CRF and PGF2 alpha, a significant increase in contractile activity was observed (P < 0.01); preincubation with CRF-BP prevented the increased contractile activity induced by CRF. The present data show that CRF-BP is able to counteract the biological effect of CRF on human pregnancy endometrium and myometrium and suggest that CRF-BP may be a regulatory protein that plays a role in the local function of uterine tissues during pregnancy. PMID:7559899

  12. Expression of prostanoid receptors in human lower segment pregnant myometrium.

    PubMed

    Leonhardt, Andreas; Glaser, Alexander; Wegmann, Markus; Hackenberg, Reinhard; Nüsing, Rolf M

    2003-11-01

    Prostanoids, especially prostaglandin (PG) E(2), are important mediators of uterine relaxation and contractions during gestation and parturition. Inhibitors of PG formation as well as PG analogues are used to modulate uterine tonus. So far, only limited data are available regarding the expression of prostanoid receptors in human pregnant myometrium. In the present study, the expression of the receptors for PGE(2) (EP1, EP2, EP3, EP4), PGF(2alpha) (FP), prostacyclin (IP), and thromboxane A(2) (TP) in human pregnant myometrium was studied by RT-PCR, in situ hybridization and immunohistochemistry. Myometrial tissue was obtained from five women at term and not in labour and from two women who delivered preterm. Tissue specimens were excised from the upper edge of the transverse lower uterine segment incision. In all tissues analysed, EP1, EP2, EP3, EP4, FP, TP and IP receptor mRNA and protein was detected. mRNA expression for PGD(2) (DP) receptor was not detected in the majority of tissue specimens. EP1, EP2, EP4, IP, TP and FP receptor protein was detected on myometrial smooth muscle cells, whereas EP3 receptor protein was only expressed by stromal and endothelial cells. In situ hybridization experiments yielded similar results. The expression of the EP2 receptor mRNA was inversely related to gestational age. We suggest that the contractile effect of PGE(2) at term is probably mediated directly by the EP1 receptor expressed in myometrial smooth muscle cells and indirectly by the EP3 receptor expressed in stromal cells and a decrease in EP2 receptor expression. PMID:14580364

  13. Inhibition of tissue transglutaminase 2 attenuates contractility of pregnant human myometrium.

    PubMed

    Alcock, Joelle; Warren, Averil Y; Goodson, Yvonne J; Hill, Stephen J; Khan, Raheela N; Lymn, Joanne S

    2011-04-01

    Premature delivery remains a serious risk factor in pregnancy, with currently licensed tocolytics unable to offer significant improvement in neonatal outcome. Further understanding of the regulators of uterine contractility is required to enable the development of novel and more effective tocolytic therapies. The transglutaminase family is a class of calcium-dependent, transamidating enzymes, of which tissue transglutaminase 2 is a multifunctional enzyme with roles in cell survival, migration, adhesion, and contractility. The aim of the present study was to investigate the role of this enzyme in regulating the contractility of pregnant human myometrium. Tissue strips from biopsy samples obtained at elective cesarean section were either allowed to contract spontaneously or induced to contract with oxytocin, phenylephrine, or bradykinin. Activity integrals, used to measure contractile activity, were taken following cumulative additions of the reversible, polyamine transglutaminase inhibitors cystamine and mono-dansylcadaverine and the irreversible, site-specific transglutaminase inhibitors N-benzyloxycarbonyl-l-phenylalanyl-6-dimethylsulfonium-5-oxo-L-norleucine and 1,3-dimethyl-2[(oxopropyl)thio]imidazolium. The ability of cystamine and mono-dansylcadaverine to affect oxytocin-mediated calcium mobilization within primary cultured myometrial cells was also measured utilizing a calcium indicator. All inhibitors attenuated myometrial contractions in a concentration-dependent manner independent of the method of contraction stimulus. Similarly cultured myometrial cells preincubated with cystamine and mono-dansylcadaverine displayed an altered calcium response to oxytocin stimulation. Our findings demonstrate a potential role for tissue transglutaminase 2 in regulating uterine contractility in pregnant human myometrium that may be associated with the calcium signaling cascade required for contraction. PMID:21123816

  14. Invariant NKT Cell Activation Induces Late Preterm Birth That Is Attenuated by Rosiglitazone.

    PubMed

    St Louis, Derek; Romero, Roberto; Plazyo, Olesya; Arenas-Hernandez, Marcia; Panaitescu, Bogdan; Xu, Yi; Milovic, Tatjana; Xu, Zhonghui; Bhatti, Gaurav; Mi, Qing-Sheng; Drewlo, Sascha; Tarca, Adi L; Hassan, Sonia S; Gomez-Lopez, Nardhy

    2016-02-01

    Preterm birth (PTB) is the leading cause of neonatal morbidity and mortality worldwide. Although intra-amniotic infection is a recognized cause of spontaneous preterm labor, the noninfection-related etiologies are poorly understood. In this article, we demonstrated that the expansion of activated CD1d-restricted invariant NKT (iNKT) cells in the third trimester by administration of α-galactosylceramide (α-GalCer) induced late PTB and neonatal mortality. In vivo imaging revealed that fetuses from mice that underwent α-GalCer-induced late PTB had bradycardia and died shortly after delivery. Yet, administration of α-GalCer in the second trimester did not cause pregnancy loss. Peroxisome proliferator-activated receptor (PPAR)γ activation, through rosiglitazone treatment, reduced the rate of α-GalCer-induced late PTB and improved neonatal survival. Administration of α-GalCer in the third trimester suppressed PPARγ activation, as shown by the downregulation of Fabp4 and Fatp4 in myometrial and decidual tissues, respectively; this suppression was rescued by rosiglitazone treatment. Administration of α-GalCer in the third trimester induced an increase in the activation of conventional CD4(+) T cells in myometrial tissues and the infiltration of activated macrophages, neutrophils, and mature dendritic cells to myometrial and/or decidual tissues. All of these effects were blunted after rosiglitazone treatment. Administration of α-GalCer also upregulated the expression of inflammatory genes at the maternal-fetal interface and systemically, and rosiglitazone treatment partially attenuated these responses. Finally, an increased infiltration of activated iNKT-like cells in human decidual tissues is associated with noninfection-related preterm labor/birth. Collectively, these results demonstrate that iNKT cell activation in vivo leads to late PTB by initiating innate and adaptive immune responses and suggest that the PPARγ pathway has potential as a target for

  15. [Indications and risk factors for emergency obstetric hysterectomy].

    PubMed

    Nava Flores, Jorge; Paez Angulo, José Antonio; Veloz Martínez, Guadalupe; Sánchez Valle, Verónica; Hernández-Valencia, Marcelino

    2002-06-01

    Emergency obstetric hysterectomy is a procedure that potentially preserves the life and the postpartum bleeding is the direct cause of its indication, the hemorrhage postpartum happens in 1% of obstetric patients. This study was carried out to identify women with potential risk for this event and to prevent this obstetric problem. The most frequent indications for hysterectomy were identified, as well as the sociodemographic characteristic of the patients. The surgical procedure carried out was extra-fascial technique with type Richardson hysterectomy modified; the surgical pieces went to the pathology service, to obtain the histopathological diagnosis. 43 cases of obstetric hysterectomy, were analyzed; the characteristics of this group showed that bigger percentage of this event was more frequent in 31 to 35 years (39.5%), with pregnancies at term (51.1%) in third pregnancies(27.9%), nulliparas (60.4%), with first cesarean section (39.5%), without previous abortions (79.0%). The most frequent obstetric complications were uterine atony and placenta accreta. The cause for uterine atony could be interstitial edema, as well as myometrial hypertrophy, because such histopathological diagnoses were the most common. Odds ratio showed that a patient with cesarean section has 1.16 more probabilities of suffering hysterectomy than a woman with childbirth. This study describes the histological presence of interstitial edema and myometrial hypertrophy as possible causes of uterine atony in the histological study of surgical specimen. This could be related to no response of myometrial to the uterus-tonic effect of oxytocin. Obstetric uterine dysfunction has multifactorial cause. Patients with the characteristics described in this study should be considered as high risk. PMID:12148472

  16. Effects of ovarian steroids upon responses mediated by adrenoceptors in separated layers of the myometrium and in the costo-uterine muscle of the guinea-pig

    PubMed Central

    Hartley, Margaret L.; Pennefather, Jocelyn N.; Story, Margot E.

    1983-01-01

    1 This study describes the effects of ovarian steroid hormones upon the responses to adrenoceptor agonists of isolated myometrium, separated into its longitudinal and circular layers, and of costo-uterine muscle from guinea-pigs. The preparations were field-stimulated at 100 s intervals, and the adrenoceptor agonists phenylephrine and isoprenaline produced enhancement or inhibition of the evoked contractions. 2 Isoprenaline produced propranolol-sensitive inhibitory effects in longitudinal and circular myometrium and costo-uterine muscle preparations from animals from all experimental groups: i.e. from nonsteroid-treated animals (ovariectomized and intact); intact animals treated with either oestrogen or progesterone alone; ovariectomized animals treated with oestrogen; ovariectomized and intact animals treated with progesterone following oestrogen priming; and from animals 1-4 days post-partum. Longitudinal myometrial preparations from progesterone-treated oestrogen-primed and from post-partum animals were most sensitive to this agonist. 3 Phenylephrine produced phentolamine-sensitive excitatory effects in circular myometrial and costo-uterine muscle preparations from animals from all the experimental groups. In contrast, propranolol-sensitive inhibitory responses to phenylephrine occurred in longitudinal myometrial preparations taken from animals treated with progesterone following oestrogen priming, and from post-partum animals. Longitudinal myometrium from animals from the remaining experimental groups exhibited phentolamine-sensitive excitatory responses to phenylephrine. 4 The basis for the selective effect upon the longitudinal myometrium of exposure to progesterone following a period of oestrogen priming, is discussed. The results described are consistent with the possibility that in the longitudinal layer of guinea-pig uterus exposed to progesterone following oestrogen priming there is an increase in the proportion of β-adrenoceptors in this layer. This

  17. 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

  18. Three-dimensional imaging of the uterus: The value of the coronal plane.

    PubMed

    Wong, Lufee; White, Nikki; Ramkrishna, Jayshree; Araujo Júnior, E; Meagher, Simon; Costa, Fabricio Da Silva

    2015-12-28

    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

  19. Tocodynamometry detects preterm labor in the bitch before luteolysis.

    PubMed

    Davidson, Autumn P

    2015-03-01

    Preterm labor (PTL), myometrial activity, and accompanying cervical changes can lead to the loss of pregnancy via resorption or abortion before term gestation. Idiopathic PTL has no metabolic, infectious, congenital, traumatic, or toxic cause identified; however, hypoluteoidism has been hypothesized to cause PTL in the bitch, based on progesterone measurements at the time of clinical pregnancy loss. This study documents the use of tocodynamometry to detect PTL in 5 bitches; progesterone measurements in these bitches were normal for pregnancy at the time PTL was diagnosed. PMID:26041589

  20. 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

  1. Fenamates may antagonize the actions of prostaglandin endoperoxides in human myometrium.

    PubMed Central

    Sanger, G J; Bennett, A

    1979-01-01

    1 The prostaglandin endoperoxide analogue U-46619 potently contracted human isolated myometrium, suggesting that prostaglandin H2 (PGH2) may be a major stimulant of myometrial contractions. 2 Sodium mefenamate, flufenamate or meclofenamate 2 microgram/ml greatly reduced contractions of the myometrium induced by the PGH2 analogue. 3 Flufenamate, but not the other two drugs, also significantly inhibited contractions to acetylcholine. 4 Sodium meclofenamate 2 microgram/ml did not consistently antagonize contractions to PGF2alpha. 5 The relief of dysmenorrhoea by fenamates may be explained both by inhibition of PG synthesis, and by antagonism of contractions to PGH2 produced by incompletely blocked PG synthesis. PMID:508555

  2. [The dynamics of the rapid changes in the phospholipids of the whole blood and blood cells in patients with endometriosis interna].

    PubMed

    Kulakov, V I; Sliusar', N N; Bakuleva, L P; Damirov, M M; Kargapolov, A V

    1993-01-01

    Time course of rapid changes in blood phospholipids and blood cells was studied in 44 patients with endometriosis. Rapid reversible blood phospholipid changes were observed when these patients' red cells and lymphocytes were incubated with calcium chloride. Time course of rapid changes in phosphoinosites, sphyngomyelines, phosphatidylserines, phosphlatidylethanolamines of patients' red and white blood cells, whole blood, and myometrial tissue differed significantly from that in healthy women. The authors suppose that cellular proliferation processes in endometriosis are connected with phospholipid homeostasis disorders in blood cells and tissue. PMID:8250135

  3. Adenomyosis: Difficult to Diagnose, and Difficult to Treat

    PubMed Central

    2001-01-01

    Drug therapy may be effective in controlling symptoms but the frequent coexistence of endometriosis and the lack of controlled studies make their efficacy difficult to quantify. Danazol IUD has been shown to reduce symptoms. Conservative surgery involving endomyometrial ablation, laparoscopic myometrial electrocoagulation or excision has proven to be effective in more than 50% of patients, although follow up has been restricted to three years. Arterial uterine artery embolization is a new technique which may be tried before considering hysterectomy. Hysterectomy may still be necessary in severe cases of adenomyosis. PMID:18493552

  4. 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

  5. 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.

  6. 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.

  7. 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.

  8. Spatial aggregation and the species-area relationship across scales.

    PubMed

    Grilli, Jacopo; Azaele, Sandro; Banavar, Jayanth R; Maritan, Amos

    2012-11-21

    There has been a considerable effort to understand and quantify the spatial distribution of species across different ecosystems. Relative species abundance (RSA), beta diversity and species-area relationship (SAR) are among the most used macroecological measures to characterize plants communities in forests. In this paper we introduce a simple phenomenological model based on Poisson cluster processes which allows us to exactly link RSA and beta diversity to SAR. The framework is spatially explicit and accounts for the spatial aggregation of conspecific individuals. Under the simplifying assumption of neutral theory, we derive an analytical expression for the SAR which reproduces tri-phasic behavior as sample area increases from local to continental scales, explaining how the tri-phasic behavior can be understood in terms of simple geometric arguments. We also find an expression for the endemic area relationship (EAR) and for the scaling of the RSA. PMID:22902426

  9. 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

  10. 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

  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. Keep focussing: striatal dopamine multiple functions resolved in a single mechanism tested in a simulated humanoid robot.

    PubMed

    Fiore, Vincenzo G; Sperati, Valerio; Mannella, Francesco; Mirolli, Marco; Gurney, Kevin; Friston, Karl; Dolan, Raymond J; Baldassarre, Gianluca

    2014-01-01

    The effects of striatal dopamine (DA) on behavior have been widely investigated over the past decades, with "phasic" burst firings considered as the key expression of a reward prediction error responsible for reinforcement learning. Less well studied is "tonic" DA, where putative functions include the idea that it is a regulator of vigor, incentive salience, disposition to exert an effort and a modulator of approach strategies. We present a model combining tonic and phasic DA to show how different outflows triggered by either intrinsically or extrinsically motivating stimuli dynamically affect the basal ganglia by impacting on a selection process this system performs on its cortical input. The model, which has been tested on the simulated humanoid robot iCub interacting with a mechatronic board, shows the putative functions ascribed to DA emerging from the combination of a standard computational mechanism coupled to a differential sensitivity to the presence of DA across the striatum. PMID:24600422

  13. 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

  14. 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.

  15. 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.

  16. 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

  17. 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

  18. 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

  19. 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

  20. 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

  1. 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.

  2. Specific features of the planarian Dugesia tigrina regeneration and mollusk Helix albescens nociception under weak electromagnetic shielding

    NASA Astrophysics Data System (ADS)

    Temur'yants, N. A.; Demtsun, N. A.; Kostyuk, A. S.; Yarmolyuk, N. S.

    2012-12-01

    It has been demonstrated that weak electromagnetic shielding stimulates regeneration in the planarian Dugesia tigrina, the stimulating intensity being dependent on both the initial state of the animals, which is determined by season, and their functional asymmetry. As has been shown, the effect of a weak electromagnetic field induces phasic changes in the nociceptive sensitivity of the mollusk Helix albescens: an increase in the sensitivity to a thermal stimulus is replaced by the development of the hypalgesic effect.

  3. Relationship between regional myocardial blood flow and thallium-201 distribution in the presence of coronary artery stenosis and dipyridamole-induced vasodilation

    SciTech Connect

    Mays, A.E. Jr.; Cobb, F.R.

    1984-05-01

    This study assesses the relationship between the distribution of thallium-201 and myocardial blood flow during coronary vasodilation induced by intravenous dipyridamole in canine models of partial and complete coronary artery stenosis. 10 dogs were chronically instrumented with catheters in the left atrium and aorta and with a balloon occluder and electromagnetic flow probe on the proximal left circumflex coronary artery. Regional myocardial blood flow was measured during control conditions with radioisotope-labeled microspheres, and the phasic reactive hyperemic response to a 20-s transient occlusion was then recorded. Dipyridamole was then infused intravenously until phasic coronary blood flow increased to match peak hyperemic values. The left circumflex coronary artery was either partially occluded to reduce phasic blood flow to control values (group 1) or it was completely occluded (group 2), and thallium-201 and a second microsphere label were injected. 5 min later, the animals were sacrificed, the left ventricle was sectioned into 1-2-g samples, and thallium-201 activity and regional myocardial blood flow were measured. Curvilinear regression analyses between thallium-201 localization and myocardial blood flow during dipyridamole infusion demonstrated a slightly better fit to a second- as compared with a first-order model, indicating a slight roll-off of thallium activity as myocardial blood flow increases. During the dipyridamole infusion, the increases in phasic blood flow, the distributions of regional myocardial blood flow, and the relationships between thallium-201 localization and regional blood flow were comparable to values previously observed in exercising dogs with similar occlusions. These data provide basic validation that supports the use of intravenous dipyridamole and thallium-201 as an alternative to exercise stress and thallium-201 for evaluating the effects of coronary occlusive lesions on the distribution of regional myocardial blood flow.

  4. Development imaging and experimental model for studying pathogenesis and treatment efficacy of postmastectomy lymphedema

    NASA Astrophysics Data System (ADS)

    Galanzha, Ekateryna I.; Tuchin, Valery V.; Solov'eva, Anastasiya V.; Stepanova, Tatyana V.; Brill, Gregory E.; Zharov, Vladimir P.

    2002-05-01

    The experimental model was created during an abdominal dissection of the rat mesentery and ligation of the collecting vein of mesentery. It was found that mesentery edema was developed for 20-30 min. Simultaneously monitoring of main the parameters of blood and lymph flow revealed significant increasing of interstitial water amount (up to 3 times), reduction of blood microcirculation, increasing of blood vessels permeability, decreasing of lymph microvessels diameter, phasics contractions, and lymph flow velocity.

  5. 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

  6. 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

  7. High-definition spatiotemporal mapping of contractile activity in the isolated proximal colon of the rabbit.

    PubMed

    Lentle, Roger G; Janssen, Patrick W M; Asvarujanon, Patchana; Chambers, Paul; Stafford, Kevin J; Hemar, Yacine

    2008-03-01

    Four types of contractile activity were identified and characterised in the isolated triple haustrated proximal colon of the rabbit using high-definition spatiotemporal mapping techniques. Mass peristalses were hexamethonium-sensitive deep circular contractions with associated taenial longitudinal contractile activity that occurred irregularly and propagated rapidly aborad, preceded by a zone of local lumen distension. They were sufficiently sustained for each event to occupy the length of the isolated colonic segment and the contraction persisted longer orally than aborally, the difference being more pronounced when lumen contents were viscous. Haustra were bounded by deep even-spaced ring contractions that progressed slowly aborad (haustral progression). Haustral formation and progression were hexamethonium-sensitive and coordinated across intertaenial domains. Ripples were hexamethonium-resistant phasic circular contractions that propagated predominantly orad at varying rates. In the presence of haustra, they were uncoordinated across intertaenial domains but were more coordinated when haustra were absent. Fast phasic contractions were relatively shallow hexamethonium-resistant contractions that propagated rapidly in a predominantly aborad direction. Fast phasic circular contractions were accompanied by taenial longitudinal muscle contractions which increased in amplitude prior to a mass peristaltic event and following the administration of hexamethonium. On the basis of the concurrence and interaction of these contractile activities, we hypothesise that dual pacemakers are present with fast phasic contractions being modulated by the interstitial cells of Cajal in the Auerbach's plexus (ICC-MY) while ripples are due to the submucosal ICC (ICC-SM). Further, that ICC-SM mediate the enteric motor neurons that generate haustral progression, while the intramuscular ICC (ICC-IM) mediate mass peristalsis. The orad movement of watery fluid was possibly due to ripples in

  8. Effects of arousal on cognitive control: empirical tests of the conflict-modulated Hebbian-learning hypothesis.

    PubMed

    Brown, Stephen B R E; van Steenbergen, Henk; Kedar, Tomer; Nieuwenhuis, Sander

    2014-01-01

    An increasing number of empirical phenomena that were previously interpreted as a result of cognitive control, turn out to reflect (in part) simple associative-learning effects. A prime example is the proportion congruency effect, the finding that interference effects (such as the Stroop effect) decrease as the proportion of incongruent stimuli increases. While this was previously regarded as strong evidence for a global conflict monitoring-cognitive control loop, recent evidence has shown that the proportion congruency effect is largely item-specific and hence must be due to associative learning. The goal of our research was to test a recent hypothesis about the mechanism underlying such associative-learning effects, the conflict-modulated Hebbian-learning hypothesis, which proposes that the effect of conflict on associative learning is mediated by phasic arousal responses. In Experiment 1, we examined in detail the relationship between the item-specific proportion congruency effect and an autonomic measure of phasic arousal: task-evoked pupillary responses. In Experiment 2, we used a task-irrelevant phasic arousal manipulation and examined the effect on item-specific learning of incongruent stimulus-response associations. The results provide little evidence for the conflict-modulated Hebbian-learning hypothesis, which requires additional empirical support to remain tenable. PMID:24523690

  9. 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

  10. Temporal patterns and selectivity in the unitary responses of olfactory receptors in the tiger salamander to odor stimulation.

    PubMed

    Baylin, F

    1979-07-01

    Temporal patterns and selectivity in unitary responses of 100 single olfactory receptors in the tiger salamander to odor stimulation were investigated. An olfactometer which permitted control of stimulus concentration, duration, and flow rate was calibrated with a gas chromatograph. Stimulus pulses were monitored by recording the electroolfactogram from the surface of the olfactory epithelium. Both diphasic and triphasic spikes were recorded extracellularly. No discernible differences in types of responses, reproducibility of responses, and cross-unit distribution of spontaneous rates distinguished diphasic from triphasic units. The cross-unit selectivity in responses to the seven olfactory stimulants used and the range of odorant concentrations which effectively evoked these responses suggest variations in types and number of types of receptive sites on each cell. Temporal patterns in the unitary responses were generally less complex than those observed in the olfactory bulb. Phasic stimulations evoked phasic patterns. Tonic stimulations evoked phasic/tonic patterns. Occasionally poststimulus depressions or elevations in firing rates were observed. The nature of these patterns varied somewhat with odorant concentration for a particular unit. PMID:479819

  11. 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

  12. 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

  13. 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

  14. [Disturbance of active sleep components in neonates with congenital hypothyroidism].

    PubMed

    Araki, S; Toyoura, T; Kohyama, J; Shimohira, M; Iwakawa, Y

    1996-11-01

    In order to investigate the effect of hypothyroidism during the early development on the functional brainstem maturation, polysomnograms were recorded on 7 patients with congenital hypothyroidism detected by neonatal screening before treatment. The following two sleep indices for phasic muscle activity during rapid eye movement (REM) sleep were evaluated: dissociation index (DI) and % body movements in REMs burst (% BM). The DI is defined as the ratio of the number of twitch movements (TMs) during REM sleep to the sum of TMs and localized movements (LMs) during REM sleep. The % BM is the percentage of TMs and LMs which occur during bursts of REMs in relation to the sum of TMs and LMs during REM sleep. The DI and % BM can reflect maturation of the tonic and phasic inhibitory system functioning during REM sleep, respectively. In congenital hypothyroidism, DI was lower than that in controls, while % BM was identical. The tonic inhibitory system was specifically involved, whereas the phasic one was preserved. It is suggested that thyroid hormone could play an important role on the functional brainstem maturation. We propose to investigate their neuropsychological development over the long term to elucidate the influence of hypothyroidism. PMID:8940874

  15. 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

  16. Dysregulation of striatal dopamine release in a mouse model of dystonia

    PubMed Central

    Bao, Li; Patel, Jyoti C.; Walker, Ruth H.; Shashidharan, Pullanipally; Rice, Margaret E.

    2010-01-01

    Dystonia is a neurological disorder characterized by involuntary movements. We examined striatal dopamine function in hyperactive transgenic mice generated as a model of dystonia. Evoked extracellular dopamine concentration was monitored with carbon-fiber microelectrodes and fast-scan cyclic voltammetry in striatal slices from non-transgenic mice, transgenic mice with a positive motor phenotype, and phenotype-negative transgenic littermates. Peak single-pulse evoked dopamine concentration was significantly lower in phenotype-positive mice than in non-transgenic or phenotype-negative mice, but indistinguishable between non-transgenic and phenotype-negative mice. Phenotype-positive mice also had higher functional D2 dopamine autoreceptor sensitivity than non-transgenic mice, which would be consistent with lower extracellular dopamine concentration in vivo. Multiple-pulse (phasic) stimulation (5 pulses, 10-100 Hz) revealed an enhanced frequency dependence of evoked dopamine release in phenotype-positive versus non-transgenic or phenotype-negative mice, which was exacerbated when extracellular Ca2+ concentration was lowered. Enhanced sensitivity to phasic stimulation in phenotype-positive mice was reminiscent of the pattern seen with antagonism of nicotinic acetylcholine receptors. Consistent with a role for altered cholinergic regulation, the difference in phasic responsiveness among groups was lost when nicotinic receptors were blocked by mecamylamine. Together, these data implicate compromised dopamine release regulation, possibly from cholinergic dysfunction, in the motor symptoms of this dystonia model. PMID:20626557

  17. 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

  18. Distinct prestimulus and poststimulus activation of VTA neurons correlates with stimulus detection

    PubMed Central

    Totah, Nelson K. B.; Kim, Yunbok

    2013-01-01

    Dopamine neurons of the ventral tegmental area (VTA) signal the occurrence of a reward-predicting conditioned stimulus (CS) with a subsecond duration increase in post-CS firing rate. Important theories about reward-prediction error and reward expectancy have been informed by the substantial number of studies that have examined post-CS phasic VTA neuron activity. On the other hand, the role of VTA neurons in anticipation of a reward-predicting CS and analysis of prestimulus spike rate rarely has been studied. We recorded from the VTA in rats during the 3-choice reaction time task, which has a fixed-duration prestimulus period and a difficult-to-detect stimulus. Use of a stimulus that was difficult to detect led to behavioral errors, which allowed us to compare VTA activity between trials with correct and incorrect stimulus-guided choices. We found a sustained increase in firing rate of both putative dopamine and GABA neurons during the pre-CS period of correct and incorrect trials. The poststimulus phasic response, however, was absent on incorrect trials, suggesting that the stimulus-evoked phasic response of dopamine neurons may relate to stimulus detection. The prestimulus activation of VTA neurons may modulate cortical systems that represent internal states of stimulus expectation and provide a mechanism for dopamine neurotransmission to influence preparatory attention to an expected stimulus. PMID:23554430

  19. Effects of arousal on cognitive control: empirical tests of the conflict-modulated Hebbian-learning hypothesis

    PubMed Central

    Brown, Stephen B. R. E.; van Steenbergen, Henk; Kedar, Tomer; Nieuwenhuis, Sander

    2014-01-01

    An increasing number of empirical phenomena that were previously interpreted as a result of cognitive control, turn out to reflect (in part) simple associative-learning effects. A prime example is the proportion congruency effect, the finding that interference effects (such as the Stroop effect) decrease as the proportion of incongruent stimuli increases. While this was previously regarded as strong evidence for a global conflict monitoring-cognitive control loop, recent evidence has shown that the proportion congruency effect is largely item-specific and hence must be due to associative learning. The goal of our research was to test a recent hypothesis about the mechanism underlying such associative-learning effects, the conflict-modulated Hebbian-learning hypothesis, which proposes that the effect of conflict on associative learning is mediated by phasic arousal responses. In Experiment 1, we examined in detail the relationship between the item-specific proportion congruency effect and an autonomic measure of phasic arousal: task-evoked pupillary responses. In Experiment 2, we used a task-irrelevant phasic arousal manipulation and examined the effect on item-specific learning of incongruent stimulus–response associations. The results provide little evidence for the conflict-modulated Hebbian-learning hypothesis, which requires additional empirical support to remain tenable. PMID:24523690

  20. A transient outward current related to calcium release and development of tension in elephant seal atrial fibres.

    PubMed Central

    Maylie, J; Morad, M

    1984-01-01

    Membrane currents and development of tension in atrial trabeculae from elephant seal hearts were studied using a single sucrose-gap voltage-clamp technique. A transient outward current (Ito) was observed with kinetics, voltage and beat dependence, similar to those of tension. Ito had a bell-shaped voltage dependence similar to that of tension and the slow inward current (Isi). Ito, unlike Isi, showed beat dependence quite similar to developed tension. Increases in [Ca]o, frequency of stimulation, and addition of adrenaline enhanced Ito and developed tension. Ito was suppressed by addition of Mn2+, tetracaine, or by depolarizing pre-pulses (to -40 mV for 250 ms). Caffeine at low concentrations (1 mM) blocked beat dependence of Ito. At higher concentrations (greater than 5 mM) caffeine suppressed the activation of Ito, phasic tension, and the second component of the birefringence signal (related to Ca2+-releasing activity of the sarcoplasmic reticulum (s.r.]. Similar to Isi phasic tension and Ito, the voltage dependence of the second component of the birefringence signal was bell-shaped. Our studies suggest that activation of Ito is related to triggered release of Ca2+ from the s.r. which generates the phasic tension. An excitation-contraction coupling scheme is presented which incorporates these findings and suggests that Ito may be responsible for shorter action potentials found in atrial fibres. Images Plate 1 PMID:6512692

  1. Effect of cooling on supraoptic neurohypophysial neuronal activity and on urine flow in the rat.

    PubMed Central

    Ferguson, A V; Pittman, Q J; Riphagen, C L

    1984-01-01

    The activity of antidromically identified supraoptic neurosecretory neurones was recorded in Sprague-Dawley rats under urethane or sodium pentobarbitone anaesthesia during cooling of the body with a cold pack. Of twelve phasic neurones studied during a complete cooling and rewarming cycle, six displayed an initial increase, followed by a depression in activity during the period of reduced body temperature. The remaining six phasic neurones did not alter their activity during cooling. Non-phasic neurohypophysial neurones displayed a reversible reduction (n = 8), or increase (n = 6) in activity during cooling, while seven neurones were unaffected by changes in body temperature. In four other anaesthetized Sprague-Dawley rats, urine flow was reduced by approximately 50% during cooling; this was followed by a diuresis after removal of the cold pack and return of body temperature to normal. The antidiuresis did not occur in homozygous Brattleboro rats which lack arginine vasopressin. The electrophysiological data from a proportion of the supraoptic neurohypophysial neurones correlate with the observed changes in urine flow. PMID:6747884

  2. [Cyclicity, reversibility and compensation of magnetobiological reactions in isolated cells and tissues].

    PubMed

    Kazanin, V I

    1986-04-01

    Cell sensitivity to a constant magnetic field (CMF) of 100 = 200 Oe was studied on a fibroblast culture using time-lapse microfilming. It was expressed in the phasic development of the motility of cells, intracellular structures and inclusions: a short-term latent phase (10-15 min), an excitation phase (1.5-2 h) and a suppression phase (up to the end of exposure). After field removal the return of cells to the initial state with a slight excess (in 1.5-2 h) was noted. The phasic development, reversibility and compensation of magnetobiological reactions were later on confirmed in studies on the inhibition in CMF of 400-600 Oe of the activity of succinate dehydrogenase and peptidase in isolated surviving rat skeletal muscles, liver and kidney as well as on a model of the reaction of a cytopathogenic effect of lymphocytes from patients with rheumatic fever on human embryonic fibroblasts where a noticeable effect of inhibition with the CMF action on the system of lymphocytes-fibroblasts and, on the contrary, of its activation with adding to fibroblasts lymphocytes preexposed in CMF of 400-600 Oe for 1 and 24 h were revealed and interpreted as supercompensation of the inhibited enzymatic activity of immunocompetent cells. The phasic development, reversibility and compensation of magnetobiological reactions should be necessarily taken into account in working out magnetotherapy. PMID:3515110

  3. 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.

  4. 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. PMID:21557648

  5. Transient, axotomy-induced changes in the membrane properties of crayfish central neurones.

    PubMed Central

    Kuwada, J Y; Wine, J J

    1981-01-01

    1. In crayfish, the normally passive, non-spiking somata of certain unipolar, efferent neurones became spiking within 36 hr of axotomy. 2. The changes persisted for approximately 2 weeks and then waned. The decline in excitability occurred independently of regeneration, and excitability was not restored by recutting the axon stump. 3. The neuropilar processes also became capable of supporting spikes, but synaptic transmission onto the cells and the spike threshold for orthodromic activation were unchanged, as was the gross structure of the neurone. 4. In somata which normally spike, electrogenicity was nevertheless increased, as evidenced by soma spikes that were larger, faster rising, and easier to evoke. 5. We tested for post-axotomy excitability changes in a variety of identified neurones. Every type (n = 5) of phasically active efferent we tested responded as above, as did all three phasic interneurones. One class of spontaneously active interneurones and one spontaneously active efferent did not respond to axotomy. 6. Extensive damage to afferents did not initiate changes in efferents of the same ganglion, nor did it interfere with changes induced by axotomy of the efferents. 7. Transection of the larger of the two main branches of the phasic flexor inhibitor induced soma excitability, but cutting the smaller branch did not. However, after the excitability caused by cutting the larger branch waned, transection of the smaller branch then induced excitability. 8. Neurones with longer axon stumps took longer to develop soma excitability. PMID:6273548

  6. The inwardly rectifying K+ channel KIR7.1 controls uterine excitability throughout pregnancy

    PubMed Central

    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

    2014-01-01

    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. PMID:25056913

  7. HMGI(Y) expression in human uterine leiomyomata. Involvement of another high-mobility group architectural factor in a benign neoplasm.

    PubMed Central

    Williams, A. J.; Powell, W. L.; Collins, T.; Morton, C. C.

    1997-01-01

    Chromosomal rearrangements involving 6p21 have been observed in uterine leiomyomata and a variety of other benign tumors. The gene for HMGI(Y), a member of the high-mobility group (HMG) family of proteins, has been localized to 6p21. To determine whether rearrangements observed in this area alter HMGI(Y) expression, we analyzed HMGI(Y) DNA-binding activity in protein extracts from uterine leiomyoma and normal myometrium tissues. This report describes a uterine leiomyoma specimen with an inv(6)(p21q15). A genomic P1 clone that contains the HMGI(Y) region of chromosome 6 is found to span the inversion breakpoint by fluorescent in situ hybridization of metaphase chromosomes. Expression of HMGI(Y) protein in this leiomyoma specimen is increased dramatically as compared with the matching normal myometrial tissue. Elevated HMGI(Y) expression was also found in 8 of 16 leiomyomas without cytogenetically detectable chromosome 6p21 aberrations but not in any of the 9 matching myometrial tissues. Analysis of the genetic events involved in the pathobiology of these benign tumors will provide a basis for understanding the process of improper cellular growth and might be important in deciphering the multistep pathway of tumorigenesis. Images Figure 1 Figure 2 Figure 3 PMID:9060829

  8. 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

  9. Transient Receptor Potential C4/5 Like Channel Is Involved in Stretch-Induced Spontaneous Uterine Contraction of Pregnant Rat

    PubMed Central

    Chung, Seungsoo; Kim, Young-Hwan; Joeng, Ji-Hyun

    2014-01-01

    Spontaneous myometrial contraction (SMC) in pregnant uterus is greatly related with gestational age and growing in frequency and amplitude toward the end of gestation to initiate labor. But, an accurate mechanism has not been elucidated. In human and rat uterus, all TRPCs except TRPC2 are expressed in pregnant myometrium and among them, TRPC4 are predominant throughout gestation, suggesting a possible role in regulation of SMC. Therefore, we investigated whether the TRP channel may be involved SMC evoked by mechanical stretch in pregnant myometrial strips of rat using isometric tension measurement and patch-clamp technique. In the present results, hypoosmotic cell swelling activated a potent outward rectifying current in G protein-dependent manner in rat pregnant myocyte. The current was significantly potentiated by 1µM lanthanides (a potent TRPC4/5 stimulator) and suppressed by 10µM 2-APB (TRPC4-7 inhibitor). In addition, in isometric tension experiment, SMC which was evoked by passive stretch was greatly potentiated by lanthanide (1µM) and suppressed by 2-APB (10µM), suggesting a possible involvement of TRPC4/5 channel in regulation of SMC in pregnant myometrium. These results provide a possible cellular mechanism for regulation of SMC during pregnancy and provide basic information for developing a new agent for treatment of premature labor. PMID:25598665

  10. Constitutive activation of Beta-catenin in uterine stroma and smooth muscle leads to the development of mesenchymal tumors in mice.

    PubMed

    Tanwar, Pradeep S; Lee, Ho-Joon; Zhang, LiHua; Zukerberg, Lawrence R; Taketo, Makoto M; Rueda, Bo R; Teixeira, Jose M

    2009-09-01

    Leiomyomas and other mesenchymally derived tumors are the most common neoplasms of the female reproductive tract. Presently, very little is known about the etiology and progression of these tumors, which are the primary indication for hysterectomies. Dysregulated WNT signaling through beta-catenin is a well-established mechanism for tumorigenesis. We have developed a mouse model that expresses constitutively activated beta-catenin in uterine mesenchyme driven by the expression of Cre recombinase knocked into the Müllerian-inhibiting substance type II receptor promoter locus to investigate its effects on uterine endometrial stroma and myometrium. These mice show myometrial hyperplasia and develop mesenchymal tumors with 100% penetrance that exhibit histological and molecular characteristics of human leiomyomas and endometrial stromal sarcomas. By immunohistochemistry, we also show that both transforming growth factor beta and the mammalian target of rapamycin are induced by constitutive activation of beta-catenin. The prevalence of the tumors was greater in multiparous mice, suggesting that their development may be a hormonally driven process or that changes in uterine morphology during pregnancy and after parturition induce injury and repair mechanisms that stimulate tumorigenesis from stem/progenitor cells, which normally do not express constitutively activated beta-catenin. Additionally, adenomyosis and endometrial gland hyperplasia were occasionally observed in some mice. These results show evidence suggesting that dysregulated, stromal, and myometrial WNT/beta-catenin signaling has pleiotropic effects on uterine function and tumorigenesis. PMID:19403928

  11. Constitutive Activation of Beta-Catenin in Uterine Stroma and Smooth Muscle Leads to the Development of Mesenchymal Tumors in Mice1

    PubMed Central

    Tanwar, Pradeep S.; Lee, Ho-Joon; Zhang, LiHua; Zukerberg, Lawrence R.; Taketo, Makoto M.; Rueda, Bo R.; Teixeira, Jose M.

    2009-01-01

    Leiomyomas and other mesenchymally derived tumors are the most common neoplasms of the female reproductive tract. Presently, very little is known about the etiology and progression of these tumors, which are the primary indication for hysterectomies. Dysregulated WNT signaling through beta-catenin is a well-established mechanism for tumorigenesis. We have developed a mouse model that expresses constitutively activated beta-catenin in uterine mesenchyme driven by the expression of Cre recombinase knocked into the Müllerian-inhibiting substance type II receptor promoter locus to investigate its effects on uterine endometrial stroma and myometrium. These mice show myometrial hyperplasia and develop mesenchymal tumors with 100% penetrance that exhibit histological and molecular characteristics of human leiomyomas and endometrial stromal sarcomas. By immunohistochemistry, we also show that both transforming growth factor beta and the mammalian target of rapamycin are induced by constitutive activation of beta-catenin. The prevalence of the tumors was greater in multiparous mice, suggesting that their development may be a hormonally driven process or that changes in uterine morphology during pregnancy and after parturition induce injury and repair mechanisms that stimulate tumorigenesis from stem/progenitor cells, which normally do not express constitutively activated beta-catenin. Additionally, adenomyosis and endometrial gland hyperplasia were occasionally observed in some mice. These results show evidence suggesting that dysregulated, stromal, and myometrial WNT/beta-catenin signaling has pleiotropic effects on uterine function and tumorigenesis. PMID:19403928

  12. Platelet-Derived Growth Factor C Is Upregulated in Human Uterine Fibroids and Regulates Uterine Smooth Muscle Cell Growth1

    PubMed Central

    Suo, Guangli; Jiang, Yong; Cowan, Bryan; Wang, Jean Y.J.

    2009-01-01

    Leiomyomata uteri (i.e., uterine fibroids) are benign tumors arising from the abnormal growth of uterine smooth muscle cells (SMCs). We show here that the expression of platelet-derived growth factor C (PDGFC) is higher in approximately 80% of uterine fibroids than in adjacent myometrial tissues examined. Increased expression of PDGFC is also observed in fibroid-derived SMCs (fSMCs) relative to myometrial-derived SMCs (mSMCs). Recombinant bioactive PDGFCC homodimer stimulates the growth of fSMCs and mSMCs in ex vivo cultures and prolongs the survival of fSMCs in Matrigel plugs implemented subcutaneously in immunocompromised mice. The knockdown of PDGF receptor-alpha (PDGFRA) through lentiviral-mediated RNA interference reduces the growth of fSMCs and mSMCs in ex vivo cultures and in Matrigel implants. Furthermore, two small molecule inhibitors of the PDGFR tyrosine kinase (i.e., imatinib and dasatinib) exerted negative effects on fSMC and mSMC growth in ex vivo cultures, albeit at concentrations that cannot be achieved in vivo. These results suggest that the PDGFCC/PDGFRA signaling module plays an important role in fSMC and mSMC growth, and that the upregulation of PDGFC expression may contribute to the clonal expansion of fSMCs in the development of uterine fibroids. PMID:19553600

  13. Uterine peristalsis-induced stresses within the uterine wall may sprout adenomyosis.

    PubMed

    Shaked, Sivan; Jaffa, Ariel J; Grisaru, Dan; Elad, David

    2015-06-01

    Adenomyosis is a disease in which ectopic endometrial glands and stromal cells appear in the uterine myometrium. This pathology is common among women of reproductive age, and in addition to chronic pelvic pain and heavy periods it may also cause infertility. The 'tissue injury and repair' mechanism in response to increased intrauterine pressures was proposed as the etiology for migration of fragments of basal endometrium into the myometrial wall. In order to investigate this mechanism, a conceptual two-dimensional model of the uterine wall subjected to intrauterine pressures was implemented using ADINA commercial software. The stress field within the uterine wall was examined for a variety of intrauterine sinusoidal pressure waves with varying frequencies. The results revealed that: (1) as the wavelength of the subjected pressure wave decreased, high concentration of stresses developed near the inner uterine cavity; (2) as the pressure wave frequency increased, high gradients of the stresses were obtained; (3) at menstrual phase, the highest stresses obtained at the endometrial-myometrial interface. Therefore, increased uterine activity results in high stresses which may lead to tissue lesions and detachment of endometrial cells. PMID:25217062

  14. 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

  15. Prokineticin 1 Induces Inflammatory Response in Human Myometrium

    PubMed Central

    Gorowiec, Marta R.; Catalano, Rob D.; Norman, Jane E.; Denison, Fiona C.; Jabbour, Henry N.

    2011-01-01

    The infiltration of human myometrium and cervix with leukocytes and the formation of a pro-inflammatory environment within the uterus have been associated with the initiation of both term and preterm parturition. The mechanism regulating the onset of this pro-inflammatory cascade is not fully elucidated. We demonstrate that prokineticin 1 (PROK1) is up-regulated in human myometrium and placenta during labor. The expression of PROK1 receptor remains unchanged during labor and is abundantly expressed in the myometrium. Gene array analysis identified 65 genes up-regulated by PROK1 in human myometrium, mainly cytokines and chemokines, including IL-1β, chemokine C-C motif ligand 3, and colony-stimulating factor 3. In addition, we demonstrate that PROK1 increases the expression of chemokine C-C motif ligand 20, IL-6, IL-8, prostaglandin synthase 2, and prostaglandin E2 and F2α secretion. The treatment of myometrial explants with 100 ng/mL of lipopolysaccharide up-regulates the expression of PROK1, PROK1 receptor, and inflammatory mediators. The infection of myometrial explants with lentiviral microRNA targeting PROK1, preceding treatment with lipopolysaccharide, reduces the expression of inflammatory genes. We propose that PROK1 is a novel inflammatory mediator that can contribute to the onset of human parturition at term and partially mediate premature onset of inflammatory pathways during bacterial infection. PMID:21983634

  16. Tamoxifen DNA damage detected in human endometrium using accelerator mass spectrometry.

    PubMed

    Martin, Elizabeth A; Brown, Karen; Gaskell, Margaret; Al-Azzawi, Farook; Garner, R Colin; Boocock, David J; Mattock, Elizabeth; Pring, David W; Dingley, Karen; Turteltaub, Kenneth W; Smith, Lewis L; White, Ian N H

    2003-12-01

    This study was aimed to establish whether tamoxifen binds irreversibly to uterine DNA when given to women. Patients were given a single therapeutic dose of [(14)C]tamoxifen citrate orally (20 mg, 0.37 or 1.85 MBq) approximately 18 h prior to hysterectomy or breast surgery. Nonmalignant uterine tissue was separated into myometrium and endometrium. DNA and protein were isolated and bound radiolabel determined by the sensitive technique of accelerator mass spectrometry. Levels of irreversible DNA binding of tamoxifen in the endometrium of treated patients were 237 +/- 77 adducts/10(12) nucleotides (mean +/- SE, n = 10). In myometrial tissues, a similar extent of DNA binding was detected (492 +/- 112 adducts/10(12) nucleotides). Binding of tamoxifen to endometrial and myometrial proteins was 10 +/- 3 and 20 +/- 4 fmol/mg, respectively. In breast tissue, sufficient DNA could not be extracted but protein binding was an order of magnitude higher than that seen with endometrial proteins (358 +/- 81 fmol/mg). These results demonstrate that after oral administration, tamoxifen forms adducts in human uterine DNA but at low numbers relative to those previously reported in women after long-term tamoxifen treatment where levels, when detected, ranged from 15000 to 130000 adducts/10(12) nucleotides. Our findings support the hypothesis that the low level of DNA adducts in human uterus is unlikely to be involved with endometrial cancer development. PMID:14679010

  17. [Uterine electromyogram: principle and interest in the diagnosis of preterm labour].

    PubMed

    Doret, M; Pasquier, J-C; Gharib, C; Gaucherand, P

    2008-02-01

    Preterm labour diagnosis rely on clinical arguments exhibiting low positive predictive values. Discrimination between uterine contractions leading to preterm delivery and physiologic uterine activity increase throughout pregnancy and remains difficult. Uterine electrical activity can be recorded non-invasively from the abdominal wall and could help in the diagnosis of preterm labour. Electrical signal characteristics are reflecting myometrial cells electrical properties which are varying throughout pregnancy and labour. During pregnancy, uterine electrical activity is very low. During term and preterm labour, uterine electrical activity increases as well as mechanical activity. Bursts become regular with high amplitude. Spectral analysis demonstrates an increase in the frequency content, as represented by the shift of the burst power density spectrum peak frequency from low to high frequencies. Consequently, the electromyogram signal reflects myometrial excitability and allows differentiating powerful uterine contractions leading to delivery from uterine physiologic activity. Moreover, electromyogram signal modifications occur before any increase in mechanical activity in the pregnant rats, allowing identification of preterm labour earlier than uterine mechanical activity measured by intrauterine pressure. Two studies performed in women present with preterm contractions are supporting the potential interest of the uterine electromyogram recording to help in the diagnosis of preterm labour; but further investigations are necessary. PMID:18036747

  18. 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. PMID:23445054

  19. 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. PMID:22781934

  20. Mechanical stretch of human uterine smooth muscle cells increases IL-8 mRNA expression and peptide synthesis.

    PubMed

    Loudon, J A Z; Sooranna, S R; Bennett, P R; Johnson, M R

    2004-12-01

    Labour is associated with increased synthesis of interleukin-8 (IL-8) by the fetal membranes and myometrium, which leads to an inflammatory infiltrate. Stretch has been shown to increase the expression of contraction-associated proteins in animal models of labour and in human myocytes in vitro. In this study, we tested the hypothesis that mechanical stretch of human myometrial cells increases IL-8 messenger ribonucleic acid (mRNA) expression. We isolated myocytes from non-pregnant women undergoing hysterectomy and pregnant women undergoing Caesarean section before and after the onset of labour. Myocytes in culture were subjected to stretch of varying intensity (6-16%) and duration (1 or 6 h) using the Flexercell system. IL-8 mRNA expression was lowest in myocytes from pregnant women not in labour, intermediate in those from non-pregnant women and greatest in those from pregnant women in labour. Stretch increased IL-8 mRNA expression independent of reproductive state. The stretch-induced increase in IL-8 mRNA expression was associated with higher IL-8 levels in the culture supernatant and enhanced promoter activity. These data suggest that stretch contributes to the increase in myometrial IL-8 synthesis associated with the onset of labour in humans. PMID:15489245

  1. The stretch-dependent potassium channel TREK-1 and its function in murine myometrium.

    PubMed

    Monaghan, Kevin; Baker, Salah A; Dwyer, Laura; Hatton, William C; Sik Park, Kyung; Sanders, Kenton M; Koh, Sang Don

    2011-03-01

    Smooth muscle of the uterus stays remarkably quiescent during normal pregnancy to allow sufficient time for development of the fetus. At present the mechanisms leading to uterine quiescence during pregnancy and how the suppression of activity is relieved at term are poorly understood. Myometrial excitability is governed by ion channels, and a major hypothesis regarding the regulation of contractility during pregnancy has been that expression of certain channels is regulated by hormonal influences. We have explored the expression and function of stretch-dependent K+ (SDK) channels, which are likely to be due to TREK channels, in murine myometrial tissues and myocytes using PCR, Western blots, patch clamp, intracellular microelectrode and isometric force measurements. TREK-1 is more highly expressed than TREK-2 in myometrium, and there was no detectable expression of TRAAK. Expression of TREK-1 transcripts and protein was regulated during pregnancy and delivery. SDK channels were activated in response to negative pressure applied to patches. SDK channels were insensitive to a broad-spectrum of K+ channel blockers, including tetraethylammonium and 4-aminopyridine, and insensitive to intracellular Ca2+. SDK channels were activated by stretch and arachidonic acid and inhibited by reagents that block TREK-1 channels, l-methionine and/or methioninol. Our data suggest that uterine excitability and contractility during pregnancy is regulated by the expression of SDK/TREK-1 channels. Up-regulation of these channels stabilizes membrane potential and controls contraction during pregnancy and down-regulation of these channels induces the onset of delivery. PMID:21224218

  2. 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.

  3. 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.

  4. 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

  5. Management of high-grade stage I adenocarcinoma of the endometrium: hysterectomy following low dose external beam pelvic irradiation

    SciTech Connect

    Shimm, D.S.; Wang, C.C.; Fuller, A.F. Jr.; Nelson, J.H. Jr.; Nikrui, N.; Young, R.H.; Scully, R.E.

    1986-02-01

    Sixty-eight patients with FIGO stage I, grade 2 or 3 adenocarcinoma of the endometrium were treated according to a protocol involving 10 Gy external pelvic irradiation, prompt hysterectomy with surgical staging, and postoperative therapy individualized according to surgical-pathologic findings. Five-year survival for the entire group was 78%, 87% for those with grade 2 disease, and 59% for those with grade 3 disease. For patients whose disease was found to be confined to the uterus, surgical stage I, the 5-year survival was 98%. Patients with surgical stage I, grades 2 and 3 disease had 97 and 100% probabilities of surviving 5 years, respectively. Five-year disease-free probability was 96% for all patients with surgical stage I carcinoma, 97% for patients with grade 2 disease, and 94% for patients with grade 3 disease. Myometrial penetration influenced survival; no patient with less than 50% myometrial penetration died or suffered a relapse, while only 40% of patients with deeper penetration survived 5 years. Twenty-three percent of patients with surgically confirmed disease spread beyond the corpus survived 5 years; 29% remained disease-free at this interval. Ten of the 68 patients developed recurrences, none has had a known pelvic recurrence. Two major complications, one requiring surgery, were seen, both in patients receiving postoperative external beam irradiation. The rationale behind low-dose, preoperative external pelvic irradiation is described, and an approach to high-grade, FIGO stage I adenocarcinoma of the endometrium is outlined.

  6. 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

  7. Clinicopathological characteristics and her-2/neu status in chinese patients with uterine papillary serous carcinoma.

    PubMed

    Ren, Yulan; Wang, Huaying; Zhou, Xiaoyan; Yang, Wentao; Huang, Xiaowei; Lu, Yongming; Shi, Daren

    2011-01-01

    Objective. To analyze clinico-pathological features of Chinese patients with UPSC, and investigate roles of Her-2/neu protein expression and gene amplification in UPSC prognosis. Methods. Thirty-six patients with UPSC treated in Cancer Hospital of Fudan University from 1996 to 2006 were analysed retrospectively. Chromogenic in situ hybridization (CISH) and immunohistochemistry (IHC) were performed to evaluate Her-2/neu gene amplification and protein expression respectively. Results. The median age was 63 years, and 61% (22/36) were late stages (stage III/IV). The 1-year, 3-year, and 5-year overall survival (OS) was 73.1%, 51.9% and 43.9%, respectively. Advanced stages (P = .0006) and deep myometrial invasion (P = .0138) were significantly associtated with a shorter OS. In 36 cases, 27.8% (10/36) showed 2+ staining and 8.3% (3/36) showed 3+ by IHC. Amplification of the Her-2/neu gene was observed in 11.1% (4/36) cases. The 5-year overall survival rate in Her-2/neu IHC 2 + ∼3+ and 0 ~ 1+ cases was 12.9% and 68.6% respectively. Her-2/neu protein expression 2 + ∼3+ was significantly associated with advanced surgical stage and worse overall survival (P = .03 and P = .0023, resp.). Conclusion. Chinese patients with UPSC showed characteristics of deep myometrial invasion, advanced stages and poor overall survival. Her-2/neu protein overexpression is associated with advanced stage and poor survival outcome. PMID:21647234

  8. Histopathological Characteristics of Endometrosis in Thoroughbred Mares in Japan: Results from 50 Necropsy Cases

    PubMed Central

    HANADA, Michiko; MAEDA, Yousuke; OIKAWA, Masa-aki

    2014-01-01

    ABSTRACT Uteri from 50 necropsied nonpregnant Japanese Thoroughbred brood mares (1–30 years of age) were investigated to clarify the histopathological characteristics of endometrosis in Japanese Thoroughbred mares and the distribution pattern of endometrosis lesions in the uterus as a whole. Endometrosis was observed in all animals over 6 years of age and in all of the 21 mares aged over 12 years of age. The affected mares showed elastofibrosis of arteries, veins and lymphatic vessels in the uterine wall, atrophy of the uterine smooth muscle layers and hyperplasia of collagen fibers among the smooth muscle fascicles of the myometrium, in addition to pathomorphologic features of endometrosis such as stromal endometrial fibrosis accompanied by endometrial atrophy, periglandular fibrosis and reduction of uterine glands. The severity of the histopathological changes increased with advancing age. Lymphatic vessels with elastofibrosis showed marked lymph congestion, leading to lymphatic edema. With increasing age, the extent of the distribution of these lesions tended to expand from focal to diffuse involvement of the entire uterus. Based on these findings, we speculate that aging plays a role in the pathogenesis of endometrosis; circulatory disturbances due to intrauterine angiosis or angiopathy, particularly reduction of the arterial blood supply and disturbance of venous drainage, resulting in a reduction of lymphatic drainage (lymphatic edema), are closely related to the onset and progression of endometrial fibrosis and myometrial atrophy with fibroplasia may result in myometrial hypofunction during the peri-implantation or puerperal period. PMID:25013358

  9. Spike coding during osmotic stimulation of the rat supraoptic nucleus

    PubMed Central

    Bhumbra, GS; Inyushkin, AN; Syrimi, M; Dyball, REJ

    2005-01-01

    Novel measures of coding based on interspike intervals were used to characterize the responses of supraoptic cells to osmotic stimulation. Infusion of hypertonic NaCl in vivo increased the firing rate of continuous (putative oxytocin) cells (Wilcoxon z = 3.84, P = 0.001) and phasic (putative vasopressin) cells (z = 2.14, P = 0.032). The irregularity of activity, quantified by the log interval entropy, was decreased for continuous (Student's t = 3.06, P = 0.003) but not phasic cells (t = 1.34, P = 0.181). For continuous cells, the increase in frequency and decrease in entropy was significantly greater (t = 2.61, P = 0.036 and t = 3.06, P = 0.007, respectively) than for phasic cells. Spike patterning, quantified using the mutual information between intervals, was decreased for phasic (z = −2.64, P = 0.008) but not continuous cells (z = −1.14, P = 0.256). Although continuous cells showed similar osmotic responses to mannitol infusion, phasic cells showed differences: spike frequency decreased (z = −3.70, P < 0.001) and entropy increased (t = −3.41, P < 0.001). Considering both cell types together, osmotic stimulation in vitro using 40 mm NaCl had little effect on firing rate (z = −0.319, P = 0.750), but increased both entropy (t = 2.75, P = 0.010) and mutual information (z = −2.73, P = 0.006) in contrast to the decreases (t = 2.92, P = 0.004 and z = −2.40, P = 0.017) seen in vivo. Responses to less severe osmotic stimulation with NaCl or mannitol were not significant. Potassium-induced depolarization in vitro increased firing rate (r = 0.195, P = 0.034), but the correlation with decreased entropy was not significant (r = −0.097, P = 0.412). Intracellular recordings showed a small depolarization and decrease in input resistance during osmotic stimulation with NaCl or mannitol, and membrane depolarization following addition of potassium. Differences in responses of oxytocin and vasopressin cells in vivo, suggest differences in the balance between the

  10. [Caffeine-induced contraction of guinea pig taenia coli (author's transl)].

    PubMed

    Takahashi, S; Chujyo, N

    1978-01-01

    Caffeine (10 or 20 mM)-induced isometric contraction of guinea pig taenia coli showed two successively occurring phasic contractions (I and II) followed by a low sustained tension. Half-time of tension decay in II was 4 approximately 6 times longer than in I. The contraction occasionally showed only a single phasic contraction, of which tension, however, decayed showing two half-times as in two phasic contractions. In the presence of procaine 0.1 approximately 0.5 mM, DNP 0.03 approximately 0.1 mM or Mn2+ 0.5 approximately 1.0 mM, II was entirely abolished whereas I was partially inhibited and such were confirmed by analyzing the time course of tension decay. Maximal tension of I decreased in parallel with lowering the external Na while II was enhanced with 50 approximately 100 mM Na and inhibited by further withdrawal of Na. I and II showed the same Ca-dependecy with respect to the inhibition by Ca deficiency and to the time course of recovery from Ca-free state. Refractoriness to caffeine after preceding caffeine-contraction also showed little difference between I and II. Sustained tension by caffeine was dependent on Ca in the same manner as tonic K-contracture. Increase in 45Ca uptake with 40 mM K was completely inhibited by 10 mM caffeine while cellular Ca content in the presence of high K markedly increased with caffeine indicating the decrease in Ca exchangeability. The above results indicate that caffeine induced contraction consists of two phasic contractions of which EC-coupling Ca is released from two different cellular sites, and that the phasic contractions are followed by a sustained low tension caused by an increased Ca influx. In the presence of high K, caffeine abolishes the increase in Ca influx by high K and sequesters the sarcoplasmic free Ca resulting in the relaxation of K-contracture. PMID:640536

  11. 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

  12. 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

  13. Dose-Related Differences in the Regional Pattern of Cannabinoid Receptor Adaptation and in Vivo Tolerance Development to Δ9-Tetrahydrocannabinol

    PubMed Central

    McKinney, Diana L.; Cassidy, Michael P.; Collier, Lauren M.; Martin, Billy R.; Wiley, Jenny L.; Selley, Dana E.; Sim-Selley, Laura J.

    2009-01-01

    Chronic treatment with Δ9-tetrahydrocannabinol (THC) produces tolerance to cannabinoid-mediated behaviors and region-specific adaptation of brain cannabinoid receptors. However, the relationship between receptor adaptation and tolerance is not well understood, and the dose-response relationship of THC-induced cannabinoid receptor adaptation is unknown. This study assessed cannabinoid receptor function in the brain and cannabinoid-mediated behaviors after chronic treatment with different dosing regimens of THC. Mice were treated twice per day for 6.5 days with the following: vehicle, 10 mg/kg THC, or escalating doses of 10 to 20 to 30 or 10 to 30 to 60 mg/kg THC. Tolerance to cannabinoid-mediated locomotor inhibition, ring immobility, antinociception, and hypothermia was produced by both ramping THC-dose paradigms. Administration of 10 mg/kg THC produced less tolerance development, the magnitude of which depended upon the particular behavior. Decreases in cannabinoid-mediated G-protein activation, which varied with treatment dose and region, were observed in autoradiographic and membrane guanosine 5′-O-(3-[35S]thio)triphosphate ([35S]GTPγS)-binding assays in brains from THC-treated mice. Agonist-stimulated [35S]GTPγS binding was reduced in the hippocampus, cingulate cortex, periaqueductal gray, and cerebellum after all treatments. Decreased agonist-stimulated [35S]GTPγS binding in the caudate-putamen, nucleus accumbens, and preoptic area occurred only after administration of 10 to 30 to 60 mg/kg THC, and no change was found in the globus pallidus or entopeduncular nucleus after any treatment. Changes in the CB1 receptor Bmax values also varied by region, with hippocampus and cerebellum showing reductions after all treatments and striatum/globus pallidus showing effects only at higher dosing regimens. These results reveal that tolerance and CB1 receptor adaptation exhibit similar dose-dependent development, and they are consistent with previous studies

  14. Comparison of the activation kinetics of the M3 acetylcholine receptor and a constitutively active mutant receptor in living cells.

    PubMed

    Hoffmann, Carsten; Nuber, Susanne; Zabel, Ulrike; Ziegler, Nicole; Winkler, Christiane; Hein, Peter; Berlot, Catherine H; Bünemann, Moritz; Lohse, Martin J

    2012-08-01

    Activation of G-protein-coupled receptors is the first step of the signaling cascade triggered by binding of an agonist. Here we compare the activation kinetics of the G(q)-coupled M(3) acetylcholine receptor (M(3)-AChR) with that of a constitutively active mutant receptor (M(3)-AChR-N514Y) using M(3)-AChR constructs that report receptor activation by changes in the fluorescence resonance energy transfer (FRET) signal. We observed a leftward shift in the concentration-dependent FRET response for acetylcholine and carbachol with M(3)-AChR-N514Y. Consistent with this result, at submaximal agonist concentrations, the activation kinetics of M(3)-AChR-N514Y were significantly faster, whereas at maximal agonist concentrations the kinetics of receptor activation were identical. Receptor deactivation was significantly faster with carbachol than with acetylcholine and was significantly delayed by the N514Y mutation. Receptor-G-protein interaction was measured by FRET between M(3)-AChR-yellow fluorescent protein (YFP) and cyan fluorescent protein (CFP)-Gγ(2). Agonist-induced receptor-G-protein coupling was of a time scale similar to that of receptor activation. As observed for receptor deactivation, receptor-G-protein dissociation was slower for acetylcholine than that for carbachol. Acetylcholine-stimulated increases in receptor-G-protein coupling of M(3)-AChR-N514Y reached only 12% of that of M(3)-AChR and thus cannot be kinetically analyzed. G-protein activation was measured using YFP-tagged Gα(q) and CFP-tagged Gγ(2). Activation of G(q) was significantly slower than receptor activation and indistinguishable for the two agonists. However, G(q) deactivation was significantly prolonged for acetylcholine compared with that for carbachol. Consistent with decreased agonist-stimulated coupling to G(q), agonist-stimulated G(q) activation by M(3)-AChR-N514Y was not detected. Taken together, these results indicate that the N514Y mutation produces constitutive activation of M(3

  15. Ceramide signalling: regulatory role in cell proliferation, differentiation and apoptosis in human epidermis.

    PubMed

    Geilen, C C; Wieder, T; Orfanos, C E

    1997-09-01

    The stratum corneum of vertebrates is a major structural compartment that provides mechanical protection and prevents skin desiccation. The water barrier function of the stratum corneum was first reported in 1944, and this was shown later to be associated with multilayered lipid lamellae localized in the extracellular spaces. The major lipid components isolated from the cornified epidermal layers are ceramides, which belong to the class of sphingolipids, cholesterol and free fatty acids; their biosynthesis is in tight relationship with the cutaneous barrier function. In studies in which the barrier is artificially disturbed, lipid biosynthesis is found to be directly regulated by barrier permeability. As mentioned above, the ceramides involved in this process are located in the extracellular spaces of the upper epidermal layers, whereas sphingomyelin, the most common sphingolipid, is an integral part of the bilayer plasma membrane of the keratinocytes. During the last few years, however, increasing evidence has shown that sphingolipids may also take part in cell signalling, and the term 'sphingomyelin cycle' has been coined to describe this novel path-way of signal transduction. Intracellular messengers of the sphingomyelin cycle are ceramides as the products of an agonist-stimulated sphingomyelin hydrolysis. Increased levels of intracellular ceramides induce cell differentiation and/or apoptosis and reduce cell proliferation. In contrast to the extracellular barrier-forming ceramides which are complex partly O-acylated species containing long-chain fatty acids, intracellular signal-transducing ceramides are not O-acylated and have acyl chain lengths of 16 and 18 carbon atoms. We present here a review of our present knowledge on the sphingomyelin cycle as a possible signal transduction pathway in the human epidermis. We discuss the common origin of extracellular ceramides constituting the lipid barrier and of intracellular ceramides generated by agonist-stimulated

  16. 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

  17. 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 (A