Science.gov

Sample records for receptor blockade decreases

  1. ETA receptor blockade attenuates hypertension and decreases reactive oxygen species in ETB receptor-deficient rats.

    PubMed

    Elmarakby, Ahmed A; Dabbs Loomis, E; Pollock, Jennifer S; Pollock, David M

    2004-11-01

    We hypothesize that endothelin-A receptor stimulation contributes to the elevated blood pressure and superoxide production in endothelin-B receptor-deficient rats on a high salt diet. Experiments were conducted on homozygous endothelin-B-deficient (sl/sl) and wild-type rats (wt) fed a high salt diet (8% NaCl) for 3 weeks. Separate groups were given normal drinking water or water containing the endothelin-A receptor antagonist, ABT-627 (5 mg/kg per day; n = 8-9 in all groups). On a normal salt diet, (sl/sl) rats had a significantly elevated systolic blood pressure compared with wt (138 +/- 3 vs 117 +/- 4 mmHg, respectively; P < 0.05). High salt diet caused a significant increase in systolic blood pressure in (sl/sl) rats compared with wt (158 +/- 2 vs 138 +/- 3 mmHg, respectively; P < 0.05). Endothelin-A receptor blockade decreased systolic blood pressure in (sl/sl) rats on high salt (125 +/- 5 mmHg; P < 0.05 vs without antagonist) without affecting the systolic blood pressure in wt (119 +/- 4 mmHg). Aortic superoxide production (lucigenin chemiluminescence) and plasma 8-isoprostane were elevated in sl/sl rats and were significantly reduced by endothelin-A receptor blockade in sl/sl, but not in wt rats. These findings suggest that endothelin-1, through the endothelin-A receptor, contributes to salt-induced hypertension and vascular superoxide production in endothelin-B-deficient rats.

  2. Selective blockade of the endothelin subtype A receptor decreases early atherosclerosis in hamsters fed cholesterol.

    PubMed Central

    Kowala, M. C.; Rose, P. M.; Stein, P. D.; Goller, N.; Recce, R.; Beyer, S.; Valentine, M.; Barton, D.; Durham, S. K.

    1995-01-01

    Recent studies suggest that endothelin and its receptors may be involved in atherogenesis. To test this hypothesis, cholesterol-fed hamsters were treated with a selective endothelin subtype A (ETA) receptor antagonist BMS-182874. Characterization of hamster atherosclerotic plaques indicated that they contained a fibrous cap of smooth muscle cells, large macrophage-foam cells, and epitopes of oxidized low density lipoprotein. Messenger RNA for both ETA and ETB receptors was detected in aortic endothelial cells, in medial smooth muscle cells, and in macrophage-foam cells and smooth muscle cells of the fibro-fatty plaques. BMS-182874 inhibited the endothelin-1-induced pressor response whereas the depressor effect was unaltered, suggesting that vascular ETA receptors were selectively blocked in vivo. In hyperlipidemic hamsters, BMS-182874 decreased the area of the fatty streak by reducing the number and size of macrophage-foam cells. The results indicated that ETA receptors and thus endothelin promoted the early inflammatory phase of atherosclerosis. Images Figure 1 Figure 2 Figure 3 Figure 5 PMID:7717449

  3. AT1 receptor blockade prevents the decrease in conduit artery flow-mediated dilatation during NOS inhibition in humans.

    PubMed

    Bellien, Jeremy; Iacob, Michele; Eltchaninoff, Helene; Bourkaib, Ryad; Thuillez, Christian; Joannides, Robinson

    2007-06-01

    Whether AT(1) (angiotenin II type 1) receptor blockade can prevent the decrease in conduit artery FMD (flow-mediated dilatation) during NOS (nitric oxide synthase) inhibition by alternative endothelial pathways has not been explored previously in humans. In 12 healthy subjects, we measured radial artery diameter (echotracking) and flow (Doppler) during FMD induced by sustained reactive hyperaemia during a control period and following NOS inhibition [1.5 mg.min(-1).l(-1) L-NMMA (N(G)-monomethyl-L-arginine)], after a single oral administration of telmisartan (80 mg) or placebo, using a randomized double-blind cross-over design. In six volunteers, we also assessed the roles of prostacyclin and EDHF (endothelium-derived hyperpolarizing factor) during radial FMD after AT(1) receptor blockade by oral administration of aspirin (500 mg) alone, aspirin+L-NMMA or aspirin+L-NMMA+fluconazole (a cytochrome epoxygenases inhibitor; 0.37 mg.min(-1).l(-1)). Telmisartan did not affect radial artery FMD in the control period (10.9+/-0.6% with placebo compared with 9.9+/-0.7% with telmisartan), but prevented its decrease after L-NMMA (9.3+/-0.8% with placebo compared with 12.6+/-1.2% with telmisartan; P<0.05) with no modification in baseline parameters, hyperaemia and radial artery endothelium-independent dilatation to sodium nitroprusside. Moreover, in telmisartan-treated subjects, radial artery FMD, compared with control (9.0+/-1.0%), was not modified by aspirin alone (9.4+/-0.7%) or associated with L-NMMA (9.5+/-0.5%), but was reduced by the combination of aspirin, L-NMMA and fluconazole (7.5+/-0.6%; P<0.05). These results demonstrate that AT(1) receptor blockade prevents the decrease in conduit artery FMD during NOS inhibition in humans, suggesting the development of a compensatory endothelial mechanism. This mechanism appears to be independent of prostacyclin and could possibly be related to an EDHF release.

  4. Blockade of NMDA receptors decreased spinal microglia activation in bee venom induced acute inflammatory pain in rats.

    PubMed

    Li, Li; Wu, Yongfang; Bai, Zhifeng; Hu, Yuyan; Li, Wenbin

    2017-03-01

    Microglial cells in spinal dorsal horn can be activated by nociceptive stimuli and the activated microglial cells release various cytokines enhancing the nociceptive transmission. However, the mechanisms underlying the activation of spinal microglia during nociceptive stimuli have not been well understood. In order to define the role of NMDA receptors in the activation of spinal microglia during nociceptive stimuli, the present study was undertaken to investigate the effect of blockade of NMDA receptors on the spinal microglial activation induced by acute peripheral inflammatory pain in rats. The acute inflammatory pain was induced by subcutaneous bee venom injection to the plantar surface of hind paw of rats. Spontaneous pain behavior, thermal withdrawal latency and mechanical withdrawal threshold were rated. The expression of specific microglia marker CD11b/c was assayed by immunohistochemistry and western blot. After bee venom treatment, it was found that rats produced a monophasic nociception characterized by constantly lifting and licking the injected hind paws, decreased thermal withdrawal latency and mechanical withdrawal threshold; immunohistochemistry displayed microglia with enlarged cell bodies, thickened, extended cellular processes with few ramifications, small spines, and intensive immunostaining; western blot showed upregulated expression level of CD11b/c within the period of hyperalgesia. Prior intrathecal injection of MK-801, a selective antagonist of NMDA receptors, attenuated the pain behaviors and suppressed up-regulation of CD11b/c induced by bee venom. It can be concluded that NMDA receptors take part in the mediation of spinal microglia activation in bee venom induced peripheral inflammatory pain and hyperalgesia in rats.

  5. Early endothelin-A receptor blockade decreases blood pressure and ameliorates end-organ damage in homozygous Ren-2 rats.

    PubMed

    Vanêcková, Ivana; Kramer, Herbert J; Bäcker, Angela; Vernerová, Zdena; Opocensky, Martin; Cervenka, Ludêk

    2005-10-01

    We have recently found that nonselective endothelin ETA/ETB receptor blockade markedly improves survival rate and ameliorates end-organ damage in male homozygous rats transgenic (TGR) for the mouse Ren-2 renin gene without lowering blood pressure. Because activation of the ETA receptor may be responsible for the detrimental effects of ET in the development of hypertension, this study was performed to determine whether ETA or ETA/ETB receptor blockade exerts these beneficial effects. TGR and age-matched normotensive Hannover Sprague-Dawley rats fed a high-salt diet received either vehicle or bosentan and atrasentan (ABT-627) as nonselective ETA/ETB and selective ETA receptor blockers, respectively, from 29 until 90 days of age. The survival rate of 48% in untreated TGR was significantly (P<0.01) improved to 79% by bosentan and to 92% by ABT-627 (ABT-627 versus bosentan P<0.05). Proteinuria, glomerulosclerosis, and cardiac hypertrophy, as well as ET-1 content in left ventricular tissue, were significantly reduced by bosentan and to a greater degree by ABT-627, which also significantly attenuated the rise in blood pressure (P<0.05). Our data indicate that the ET system, especially via ETA receptors, plays an important role in the development of hypertensive end-organ damage and confirm the concept that the predominant role of ETB receptors within the peripheral vasculature is to mediate the vasorelaxant actions of ET-1. They also demonstrate that selective blockade of ETA receptors is superior to nonselective ETA/ETB in attenuating hypertension, hypertensive organ damage, and survival rate.

  6. Beta-adrenergic receptor blockade during exercise decreases intestinal lymphocyte apoptosis but not cell loss in mice.

    PubMed

    Marra, S; Hoffman-Goetz, L

    2004-07-01

    Catecholamines induce apoptosis in various lymphoid populations. This process can occur with both alpha- and beta-adrenoreceptors. Heavy exercise increases plasma catecholamine concentrations, and is also a cause of lymphocyte apoptosis, a possible explanation for postexercise lymphocytopenia. The purpose of this study was to examine the effects of adrenoreceptor antagonism on exercise-induced decreases and apoptosis of intestinal lymphocytes. Mice received an intraperitoneal injection of phentolamine (a nonselective alpha-blocker), nadolol (a nonselective beta-blocker), or saline (vehicle) prior to an exhaustive bout of exercise. Total intestinal lymphocyte numbers, percent and number of CD3+ lymphocytes, and cell viability were assessed. Neither alpha- nor beta-antagonism prevented exercise-induced cell loss in the intestine; however, pretreatment with nadolol significantly reduced the number of apoptotic and necrotic cells. Phentolamine administration appeared to increase the incidence of cell death among intestinal lymphocytes. Both drugs decreased the percentage of CD3+ intestinal lymphocytes. Our study suggests that catecholamines are not responsible for postexercise lymphocytopenia, but beta-adrenoceptor blockade may confer protection against exercise-induced apoptosis of intestinal lymphocytes.

  7. Increased wakefulness, motor activity and decreased theta activity after blockade of the 5-HT2B receptor by the subtype-selective antagonist SB-215505

    PubMed Central

    Kantor, Sandor; Jakus, Rita; Balogh, Brigitta; Benko, Anita; Bagdy, Gyorgy

    2004-01-01

    Serotonin-2 receptor antagonists, like ritanserin, greatly enhance deep slow wave sleep (SWS-2) and low-frequency EEG power in humans and rodents. 5-HT2A and 5-HT2C receptors may be involved in these effects, but the role of the 5-HT2B receptor is still unclear.To investigate the role of the 5-HT2B receptor in regulation of the sleep–wake cycle, the subtype-selective antagonist SB-215505 (0.1, 0.3 and 1.0 mg kg−1 i.p.) was administered to Sprague–Dawley rats at light onset (beginning of passive phase). EEG, EMG and motor activity were recorded during the subsequent 8 h.SB-215505 dose-dependently increased wakefulness (W) at the expense of the intermediate stage of sleep, paradoxical sleep (PS) and SWS-2 in the first hour. Parallel to increased W, significantly increased motor activity was found. Spectral analysis of the EEG in W showed a dose-dependent decrease in power density in the 3–8 Hz frequency range (maximum effect at 6 Hz). In light slow wave sleep and SWS-2, the drug reduced low-frequency (<8 Hz) EEG power, suggesting decreased sleep intensity after SB-215505 treatment. In PS, the drug dose-dependently decreased EEG power solely in the theta (6–9 Hz) band, primarily affecting the peak power value (7 Hz).The well-known SWS-2 enhancing effect of 5-HT2 receptor antagonists is mediated by 5-HT2A and/or 5-HT2C receptors. In contrast, blockade of 5-HT2B receptors increases motor activity and W along with decreased theta activity during W and PS. Activation of 5-HT2B receptors may contribute to initiation of sleep and to theta generation during W and PS under physiological conditions. PMID:15265808

  8. Blockade of NMDA receptors in postnatal period decreased density of tyrosine hydroxylase immunoreactive axonal arbors in the medial prefrontal cortex of adult rats.

    PubMed

    Wedzony, K; Fijał, K; Chocyk, A

    2005-06-01

    Malfunction of glutamatergic neurotransmission in postnatal period is considered to be a risk factor for development of schizophrenia. Thus, the present study investigates the impact of NMDA receptor blockade in the postnatal period on the density of tyrosine hydroxylase immunoreactive axonal arbors in the rat medial prefrontal cortex. Behavioral experiments revealed that adult rats (60 days old) treated in the postnatal period with a competitive antagonist of NMDA receptors, CGP 40116 (1.25 mg/kg on days 1, 3, 6, 9; 2.5 mg/kg on days 12, 15, 18; and finally 5 mg/kg on day 21, all injections s.c.), showed enhancement of the locomotor activity stimulated by quinpirole (0.3 mg/kg s.c.) and amphetamine (0.5 mg/kg s.c.), which suggests development of functional supersensitivity of dopaminergic systems. It has been found that CGP 40116, given in postnatal period decreased the density of tyrosine hydroxylase immunoreactive axonal arbors in the medial prefrontal cortex of adult animals. The decrease was observed in superficial (II/III) and deep (V/VI) layers of the medial prefrontal cortex, while the average length of tyrosine hydroxylase immunoreactive axonal arbors was increased in both superficial and deep cortical layers. Changes in the density of tyrosine hydroxylase immunoreactive axonal arbors have not been followed by a significant decrease in the content of tyrosine hydroxylase protein measured by Western blot. Thus, NMDA receptor blockade in the early period of life evokes changes in architecture of tyrosine hydroxylase immunoreactive axonal arbors and that malfunction of glutamatergic neurotransmission, in early period of life may produce anatomical changes which resemble those observed in the brains of schizophrenics.

  9. Pharmacological blockade of the cold receptor TRPM8 attenuates autonomic and behavioral cold defenses and decreases deep body temperature

    PubMed Central

    Almeida, M. Camila; Hew-Butler, Tamara; Soriano, Renato N.; Rao, Sara; Wang, Weiya; Wang, Judy; Tamayo, Nuria; Oliveira, Daniela L.; Nucci, Tatiane B.; Aryal, Prafulla; Garami, Andras; Bautista, Diana; Gavva, Narender R.; Romanovsky, Andrej A.

    2012-01-01

    We studied M8-B, a selective and potent antagonist of the transient receptor potential melastatin-8 (TRPM8) channel. In vitro, M8-B blocked cold-induced and TRPM8-agonist-induced activation of rat, human, and murine TRPM8 channels, including those on primary sensory neurons. In vivo, M8-B decreased deep body temperature (Tb) in Trpm8+/+ mice and rats, but not in Trpm8−/− mice, thus suggesting an on-target action. The intravenous administration of M8-B was more effective in decreasing Tb in rats than the intrathecal or intracerebroventricular administration, indicating a peripheral action. M8-B attenuated cold-induced c-Fos expression in the lateral parabrachial nucleus, thus indicating a site of action within the cutaneous cooling neural pathway to thermoeffectors, presumably on sensory neurons. A low intravenous dose of M8-B did not affect Tb at either a constantly high or a constantly low ambient temperature (Ta), but the same dose readily decreased Tb if rats were kept at a high Ta during the M8-B infusion and transferred to a low Ta immediately thereafter. These data suggest that both a successful delivery of M8-B to the skin (high cutaneous perfusion) and the activation of cutaneous TRPM8 channels (by cold) are required for the hypothermic action of M8-B. At tail skin temperatures < 23°C, the magnitude of the M8-B-induced decrease in Tb was inversely related to skin temperature, thus suggesting that M8-B blocks thermal (cold) activation of TRPM8. M8-B affected all thermoeffectors studied (thermopreferendum, tail skin vasoconstriction, and brown fat thermogenesis), thus suggesting that TRPM8 is a universal cold receptor in the thermoregulation system. PMID:22323721

  10. Pharmacological blockade of the cold receptor TRPM8 attenuates autonomic and behavioral cold defenses and decreases deep body temperature.

    PubMed

    Almeida, M Camila; Hew-Butler, Tamara; Soriano, Renato N; Rao, Sara; Wang, Weiya; Wang, Judy; Tamayo, Nuria; Oliveira, Daniela L; Nucci, Tatiane B; Aryal, Prafulla; Garami, Andras; Bautista, Diana; Gavva, Narender R; Romanovsky, Andrej A

    2012-02-08

    We studied N-(2-aminoethyl)-N-(4-(benzyloxy)-3-methoxybenzyl)thiophene-2-carboxamide hydrochloride (M8-B), a selective and potent antagonist of the transient receptor potential melastatin-8 (TRPM8) channel. In vitro, M8-B blocked cold-induced and TRPM8-agonist-induced activation of rat, human, and murine TRPM8 channels, including those on primary sensory neurons. In vivo, M8-B decreased deep body temperature (T(b)) in Trpm8(+/+) mice and rats, but not in Trpm8(-/-) mice, thus suggesting an on-target action. Intravenous administration of M8-B was more effective in decreasing T(b) in rats than intrathecal or intracerebroventricular administration, indicating a peripheral action. M8-B attenuated cold-induced c-Fos expression in the lateral parabrachial nucleus, thus indicating a site of action within the cutaneous cooling neural pathway to thermoeffectors, presumably on sensory neurons. A low intravenous dose of M8-B did not affect T(b) at either a constantly high or a constantly low ambient temperature (T(a)), but the same dose readily decreased T(b) if rats were kept at a high T(a) during the M8-B infusion and transferred to a low T(a) immediately thereafter. These data suggest that both a successful delivery of M8-B to the skin (high cutaneous perfusion) and the activation of cutaneous TRPM8 channels (by cold) are required for the hypothermic action of M8-B. At tail-skin temperatures <23°C, the magnitude of the M8-B-induced decrease in T(b) was inversely related to skin temperature, thus suggesting that M8-B blocks thermal (cold) activation of TRPM8. M8-B affected all thermoeffectors studied (thermopreferendum, tail-skin vasoconstriction, and brown fat thermogenesis), thus suggesting that TRPM8 is a universal cold receptor in the thermoregulation system.

  11. Decreased Incentive Motivation Following Knockout or Acute Blockade of the Serotonin Transporter: Role of the 5-HT2C Receptor.

    PubMed

    Browne, Caleb J; Fletcher, Paul J

    2016-09-01

    Acute pharmacological elevation of serotonin (5-hydroxytryptamine; 5-HT) activity decreases operant responding for primary reinforcers, suggesting that 5-HT reduces incentive motivation. The mechanism by which 5-HT alters incentive motivation is unknown, but parallel evidence that 5-HT2C receptor agonists also reduce responding for primary reinforcers implicates this receptor as a potential candidate. These experiments examined whether chronic and acute disruptions of serotonin transporter (SERT) activity altered incentive motivation, and whether the 5-HT2C receptor mediated the effects of elevated 5-HT on behavior. To assess incentive motivation, we measured responding for three different reinforcers: a primary reinforcer (saccharin), a conditioned reinforcer (CRf), and an unconditioned sensory reinforcer (USRf). In the chronic condition, responding was compared between SERT knockout (SERT-KO) mice and their wild-type littermates. In the acute condition, responding was examined in wild-type mice following treatment with 10 or 20 mg/kg citalopram, or its vehicle. The ability of the selective 5-HT2C antagonist SB 242084 to prevent the effects of SERT-KO and citalopram on responding was subsequently examined. Both SERT-KO and citalopram reduced responding for saccharin, a CRf, and a USRf. Treatment with SB 242084 enhanced responding for a CRf and a USRf in SERT-KO mice and blocked the effects of citalopram on CRf and USRf responding. However, SB 242084 was unable to prevent the effects of SERT-KO or citalopram on responding for saccharin. These results support a powerful inhibitory function for 5-HT in the control of incentive motivation, and indicate that the 5-HT2C receptor mediates these effects of 5-HT in a reinforcer-dependent manner.

  12. Angiotensin II receptor type 1 blockade decreases CTGF/CCN2-mediated damage and fibrosis in normal and dystrophic skeletal muscles

    PubMed Central

    Cabello-Verrugio, Claudio; Morales, María Gabriela; Cabrera, Daniel; Vio, Carlos P; Brandan, Enrique

    2012-01-01

    Abstract Connective tissue growth factor (CTGF/CCN-2) is mainly involved in the induction of extracellular matrix (ECM) proteins. The levels of CTGF correlate with the degree and severity of fibrosis in many tissues, including dystrophic skeletal muscle. The CTGF overexpression in tibialis anterior skeletal muscle using an adenoviral vector reproduced many of the features observed in dystrophic muscles including muscle damage and regeneration, fibrotic response and decrease in the skeletal muscle strength. The renin–angiotensin system is involved in the genesis and progression of fibrotic diseases through its main fibrotic components angiotensin-II and its transducer receptor AT-1. The use of AT-1 receptor blockers (ARB) has been shown to decrease fibrosis. In this paper, we show the effect of AT-1 receptor blockade on CTGF-dependent biological activity in skeletal muscle cells as well as the response to CTGF overexpression in normal skeletal muscle. Our results show that in myoblasts ARB decreased CTGF-mediated increase of ECM protein levels, extracellular signal regulated kinases 1/2 (ERK-1/2) phosphorylation and stress fibres formation. In tibialis anterior muscle overexpressing CTGF using an adenovirus, ARB treatment decreased CTGF-mediated increase of ECM molecules, α-SMA and ERK-1/2 phosphorylation levels. Quite remarkable, ARB was able to prevent the loss of contractile force of tibialis anterior muscles overexpressing CTGF. Finally, we show that ARB decreased the levels of fibrotic proteins, CTGF and ERK-1/2 phosphorylation augmented in a dystrophic skeletal muscle from mdx mice. We propose that ARB is a novel pharmacological tool that can be used to decrease the fibrosis induced by CTGF in skeletal muscle associated with muscular dystrophies. PMID:21645240

  13. P2X7 receptor blockade protects against cisplatin-induced nephrotoxicity in mice by decreasing the activities of inflammasome components, oxidative stress and caspase-3

    SciTech Connect

    Zhang, Yuanyuan; Yuan, Fahuan; Cao, Xuejiao; Zhai, Zhifang; Gang Huang; Du, Xiang; Wang, Yiqin; Zhang, Jingbo; Huang, Yunjian; Zhao, Jinghong; Hou, Weiping

    2014-11-15

    Nephrotoxicity is a common complication of cisplatin chemotherapy and thus limits the use of cisplatin in clinic. The purinergic 2X7 receptor (P2X7R) plays important roles in inflammation and apoptosis in some inflammatory diseases; however, its roles in cisplatin-induced nephrotoxicity remain unclear. In this study, we first assessed the expression of P2X7R in cisplatin-induced nephrotoxicity in C57BL/6 mice, and then we investigated the changes of renal function, histological injury, inflammatory response, and apoptosis in renal tissues after P2X7R blockade in vivo using an antagonist A-438079. Moreover, we measured the changes of nod-like receptor family, pyrin domain containing proteins (NLRP3) inflammasome components, oxidative stress, and proapoptotic genes in renal tissues in cisplatin-induced nephrotoxicity after treatment with A-438079. We found that the expression of P2X7R was significantly upregulated in the renal tubular epithelial cells in cisplatin-induced nephrotoxicity compared with that of the normal control group. Furthermore, pretreatment with A-438079 markedly attenuated the cisplatin-induced renal injury while lightening the histological damage, inflammatory response and apoptosis in renal tissue, and improved the renal function. These effects were associated with the significantly reduced levels of NLRP3 inflammasome components, oxidative stress, p53 and caspase-3 in renal tissues in cisplatin-induced nephrotoxicity. In conclusions, our studies suggest that the upregulated activity of P2X7R might play important roles in the development of cisplatin-induced nephrotoxicity, and P2X7R blockade might become an effective therapeutic strategy for this disease. - Highlights: • The P2X7R expression was markedly upregulated in cisplatin-induced nephrotoxicity. • P2X7R blockade significantly attenuated the cisplatin-induced renal injury. • P2X7R blockade reduced activities of NLRP3 inflammasome components in renal tissue. • P2X7R blockade

  14. P2X7 receptor blockade protects against cisplatin-induced nephrotoxicity in mice by decreasing the activities of inflammasome components, oxidative stress and caspase-3.

    PubMed

    Zhang, Yuanyuan; Yuan, Fahuan; Cao, Xuejiao; Zhai, Zhifang; GangHuang; Du, Xiang; Wang, Yiqin; Zhang, Jingbo; Huang, Yunjian; Zhao, Jinghong; Hou, Weiping

    2014-11-15

    Nephrotoxicity is a common complication of cisplatin chemotherapy and thus limits the use of cisplatin in clinic. The purinergic 2X7 receptor (P2X7R) plays important roles in inflammation and apoptosis in some inflammatory diseases; however, its roles in cisplatin-induced nephrotoxicity remain unclear. In this study, we first assessed the expression of P2X7R in cisplatin-induced nephrotoxicity in C57BL/6 mice, and then we investigated the changes of renal function, histological injury, inflammatory response, and apoptosis in renal tissues after P2X7R blockade in vivo using an antagonist A-438079. Moreover, we measured the changes of nod-like receptor family, pyrin domain containing proteins (NLRP3) inflammasome components, oxidative stress, and proapoptotic genes in renal tissues in cisplatin-induced nephrotoxicity after treatment with A-438079. We found that the expression of P2X7R was significantly upregulated in the renal tubular epithelial cells in cisplatin-induced nephrotoxicity compared with that of the normal control group. Furthermore, pretreatment with A-438079 markedly attenuated the cisplatin-induced renal injury while lightening the histological damage, inflammatory response and apoptosis in renal tissue, and improved the renal function. These effects were associated with the significantly reduced levels of NLRP3 inflammasome components, oxidative stress, p53 and caspase-3 in renal tissues in cisplatin-induced nephrotoxicity. In conclusions, our studies suggest that the upregulated activity of P2X7R might play important roles in the development of cisplatin-induced nephrotoxicity, and P2X7R blockade might become an effective therapeutic strategy for this disease.

  15. Peripheral metabolic effects of endocannabinoids and cannabinoid receptor blockade.

    PubMed

    Engeli, Stefan

    2008-01-01

    The endocannabinoid system consists of endogenous arachidonic acid derivates that activate cannabinoid receptors. The two most prominent endocannabinoids are anandamide and 2-arachidonoyl glycerol. In obesity, increased concentrations of circulating and tissue endocannabinoid levels have been described, suggesting increased activity of the endocannabinoid system. Increased availability of endocannabinoids in obesity may over-stimulate cannabinoid receptors. Blockade of cannabinoid type 1 (CB1) receptors was the only successful clinical development of an anti-obesity drug during the last decade. Whereas blockade of CB1 receptors acutely reduces food intake, the long-term effects on metabolic regulation are more likely mediated by peripheral actions in liver, skeletal muscle, adipose tissue, and the pancreas. Lipogenic effects of CB1 receptor signalling in liver and adipose tissue may contribute to regional adipose tissue expansion and insulin resistance in the fatty liver. The association of circulating 2-arachidonoyl glycerol levels with decreased insulin sensitivity strongly suggests further exploration of the role of endocannabinoid signalling for insulin sensitivity in skeletal muscle, liver, and adipose tissue. A few studies have suggested a specific role for the regulation of adiponectin secretion from adipocytes by endocannabinoids, but that has to be confirmed by more experiments. Also, the potential role of CB1 receptor blockade for the stimulation of energy expenditure needs to be studied in the future. Despite the current discussion of safety issues of cannabinoid receptor blockade, these findings open a new and exciting perspective on endocannabinoids as regulators of body weight and metabolism.

  16. Blockade of Rostral Ventrolateral Medulla (RVLM) Bombesin Receptor Type 1 Decreases Blood Pressure and Sympathetic Activity in Anesthetized Spontaneously Hypertensive Rats

    PubMed Central

    Pinto, Izabella S.; Mourão, Aline A.; da Silva, Elaine F.; Camargo, Amanda S.; Marques, Stefanne M.; Gomes, Karina P.; Fajemiroye, James O.; da Silva Reis, Angela A.; Rebelo, Ana C. S.; Ferreira-Neto, Marcos L.; Rosa, Daniel A.; Freiria-Oliveira, André H.; Castro, Carlos H.; Colombari, Eduardo; Colugnati, Diego B.; Pedrino, Gustavo R.

    2016-01-01

    Intrathecal injection of bombesin (BBS) promoted hypertensive and sympathoexcitatory effects in normotensive (NT) rats. However, the involvement of rostral ventrolateral medulla (RVLM) in these responses is still unclear. In the present study, we investigated: (1) the effects of BBS injected bilaterally into RVLM on cardiorespiratory and sympathetic activity in NT and spontaneously hypertensive rats (SHR); (2) the contribution of RVLM BBS type 1 receptors (BB1) to the maintenance of hypertension in SHR. Urethane-anesthetized rats (1.2 g · kg−1, i.v.) were instrumented to record mean arterial pressure (MAP), diaphragm (DIA) motor, and renal sympathetic nerve activity (RSNA). In NT rats and SHR, BBS (0.3 mM) nanoinjected into RVLM increased MAP (33.9 ± 6.6 and 37.1 ± 4.5 mmHg, respectively; p < 0.05) and RSNA (97.8 ± 12.9 and 84.5 ± 18.1%, respectively; p < 0.05). In SHR, BBS also increased DIA burst amplitude (115.3 ± 22.7%; p < 0.05). BB1 receptors antagonist (BIM-23127; 3 mM) reduced MAP (–19.9 ± 4.4 mmHg; p < 0.05) and RSNA (−17.7 ± 3.8%; p < 0.05) in SHR, but not in NT rats (−2.5 ± 2.8 mmHg; −2.7 ± 5.6%, respectively). These results show that BBS can evoke sympathoexcitatory and pressor responses by activating RVLM BB1 receptors. This pathway might be involved in the maintenance of high levels of arterial blood pressure in SHR. PMID:27313544

  17. CTLA4 blockade broadens the peripheral T cell receptor repertoire

    PubMed Central

    Robert, Lidia; Tsoi, Jennifer; Wang, Xiaoyan; Emerson, Ryan; Homet, Blanca; Chodon, Thinle; Mok, Stephen; Huang, Rong Rong; Cochran, Alistair J.; Comin-Anduix, Begonya; Koya, Richard C.; Graeber, Thomas G.; Robins, Harlan; Ribas, Antoni

    2014-01-01

    Purpose To evaluate the immunomodulatory effects of CTLA-4 blockade with tremelimumab in peripheral blood mononuclear cells (PBMC). Experimental Design We used next generation sequencing to study the complementarity determining region 3 (CDR3) from the rearranged T cell receptor (TCR) variable beta (V-beta) in PBMC of 21 patients, at baseline and 30–60 days after receiving tremelimumab. Results After receiving tremelimumab there was a median of 30% increase in unique productive sequences of TCR V-beta CDR3 in 19 out of 21 patients, and a median decrease of 30% in only 2 out of 21 patients. These changes were significant for richness (p=0.01) and for Shannon index diversity (p=0.04). In comparison, serially collected PBMC from four healthy donors did not show a significant change in TCR V-beta CDR3 diversity over one year. There was a significant difference in the total unique productive TCR V-beta CDR3 sequences between patients experiencing toxicity with tremelimumab compared to patients without toxicity (p=0.05). No relevant differences were noted between clinical responders and non-responders. Conclusions CTLA4 blockade with tremelimumab diversifies the peripheral T cell pool, representing a pharmacodynamic effect of how this class of antibodies modulates the human immune system. PMID:24583799

  18. Assessment of Methods for the Intracellular Blockade of GABAA Receptors

    PubMed Central

    Atherton, Laura A.; Burnell, Erica S.; Mellor, Jack R.

    2016-01-01

    Selective blockade of inhibitory synaptic transmission onto specific neurons is a useful tool for dissecting the excitatory and inhibitory synaptic components of ongoing network activity. To achieve this, intracellular recording with a patch solution capable of blocking GABAA receptors has advantages over other manipulations, such as pharmacological application of GABAergic antagonists or optogenetic inhibition of populations of interneurones, in that the majority of inhibitory transmission is unaffected and hence the remaining network activity preserved. Here, we assess three previously described methods to block inhibition: intracellular application of the molecules picrotoxin, 4,4’-dinitro-stilbene-2,2’-disulphonic acid (DNDS) and 4,4’-diisothiocyanostilbene-2,2’-disulphonic acid (DIDS). DNDS and picrotoxin were both found to be ineffective at blocking evoked, monosynaptic inhibitory postsynaptic currents (IPSCs) onto mouse CA1 pyramidal cells. An intracellular solution containing DIDS and caesium fluoride, but lacking nucleotides ATP and GTP, was effective at decreasing the amplitude of IPSCs. However, this effect was found to be independent of DIDS, and the absence of intracellular nucleotides, and was instead due to the presence of fluoride ions in this intracellular solution, which also blocked spontaneously occurring IPSCs during hippocampal sharp waves. Critically, intracellular fluoride ions also caused a decrease in both spontaneous and evoked excitatory synaptic currents and precluded the inclusion of nucleotides in the intracellular solution. Therefore, of the methods tested, only fluoride ions were effective for intracellular blockade of IPSCs but this approach has additional cellular effects reducing its selectivity and utility. PMID:27501143

  19. P2X1 receptor blockade inhibits whole kidney autoregulation of renal blood flow in vivo

    PubMed Central

    Osmond, David A.

    2010-01-01

    In vitro experiments demonstrate that P2X1 receptor activation is important for normal afferent arteriolar autoregulatory behavior, but direct in vivo evidence for this relationship occurring in the whole kidney is unavailable. Experiments were performed to test the hypothesis that P2X1 receptors are important for autoregulation of whole kidney blood flow. Renal blood flow (RBF) was measured in anesthetized male Sprague-Dawley rats before and during P2 receptor blockade with PPADS, P2X1 receptor blockade with IP5I, or A1 receptor blockade with DPCPX. Both P2X1 and A1 receptor stimulation with α,β-methylene ATP and CPA, respectively, caused dose-dependent decreases in RBF. Administration of either PPADS or IP5I significantly blocked P2X1 receptor stimulation. Likewise, administration of DPCPX significantly blocked A1 receptor activation to CPA. Autoregulatory behavior was assessed by measuring RBF responses to reductions in renal perfusion pressure. In vehicle-infused rats, as pressure was decreased from 120 to 100 mmHg, there was no decrease in RBF. However, in either PPADS- or IP5I-infused rats, each decrease in pressure resulted in a significant decrease in RBF, demonstrating loss of autoregulatory ability. In DPCPX-infused rats, reductions in pressure did not cause significant reductions in RBF over the pressure range of 100–120 mmHg, but the autoregulatory curve tended to be steeper than vehicle-infused rats over the range of 80–100 mmHg, suggesting that A1 receptors may influence RBF at lower pressures. These findings are consistent with in vitro data from afferent arterioles and support the hypothesis that P2X1 receptor activation is important for whole kidney autoregulation in vivo. PMID:20335318

  20. Glycinergic inhibition in thalamus revealed by synaptic receptor blockade.

    PubMed

    Ghavanini, Ahmad A; Mathers, David A; Puil, Ernest

    2005-09-01

    Using juvenile rat brain slices, we examined the possibility that strychnine-sensitive receptors for glycine-like amino acids contributed to synaptic inhibition in ventrobasal thalamus, where gamma-aminobutyrate (GABA) is the prevalent inhibitory transmitter. Ventrobasal nuclei showed staining for antibodies against alpha1 and alpha2 subunits of the glycine receptor. Exogenously applied glycine, taurine and beta-alanine increased membrane conductance, effects antagonized by strychnine, indicative of functional glycine receptors. Using glutamate receptor antagonists, we isolated inhibitory postsynaptic potentials and currents (IPSPs and IPSCs) evoked by high-threshold stimulation of medial lemniscus. Like the responses to glycine agonists, these synaptic responses reversed near E(Cl). In comparative tests with GABA receptor antagonists, strychnine attenuated inhibition in a majority of neurons, but did not alter slow, GABA(B) inhibition. For complete blockade, the majority of fast IPSPs required co-application of strychnine with bicuculline or gabazine, GABA(A) receptor antagonists. Strychnine acting with an IC50 approximately = 33 nM, eliminated residual fast inhibition during selective GABA(A) receptor blockade with gabazine. The latency of onset for IPSPs was compatible with polysynaptic pathways or prolonged axonal propagation time. Strychnine lacked effects on monosynaptic, GABAergic IPSPs from zona incerta. The specific actions of strychnine implicated a glycine receptor contribution to fast inhibition in somatosensory thalamus.

  1. A pharmacological analysis of serotonergic receptors: effects of their activation of blockade in learning.

    PubMed

    Meneses, A; Hong, E

    1997-02-01

    1. The authors have tested several 5-HT selective agonists and antagonists (5-HT1A/1B, 5-HT2A/2B/2C, 5-HT3 or 5-HT4), an uptake inhibitor and 5-HT depletors in the autoshaping learning task. 2. The present work deals with the receptors whose stimulation increases or decreases learning. 3. Impaired consolidation of learning was observed after the presynaptic activation of 5-HT1B, 5-HT3 or 5-HT4 or the blockade of postsynaptic 5-HT2C/2B receptors. 4. In contrast, an improvement occurred after the presynaptic activation of 5-HT1A, 5-HT2C, and the blockade of presynaptic 5-HT2A, 5-HT2C and 5-HT3 receptors. 5. The blockade of postsynaptic 5-HT1A, 5-HT1B, 5-HT3 or 5-HT4 receptors and 5-HT inhibition of synthesis and its depletion did no alter learning by themselves. 6. The present data suggest that multiple pre- and postsynaptic serotonergic receptors are involved in the consolidation of learning. 7. Stimulation of most 5-HT receptors increases learning, however, some of 5-HT subtypes seem to limit the data storage. 8. Furthermore, the role of 5-HT receptors in learning seem to require an interaction with glutamatergic, GABAergic and cholinergic neurotransmission systems.

  2. Interaction of anesthesia, beta-receptor blockade, and blood loss in dogs with induced myocardial infarction.

    PubMed

    Prys-Roberts, C; Roberts, J G; Foëx, P; Clarke, T N; Bennett, M J; Ryder, W A

    1976-09-01

    The cardiovascular effects of halothane-nitrous oxide anesthesia, and beta-receptor blockade with either propranolol or practolol, were studied in 15 dogs in which severe myocardial infarction had been induced ten days earlier. The hemodynamic responses to blood loss amounting to 25 per cent of estimated blood volume, and its subsequent replacement, were studied before and after induction of beta-receptor blockade. In terms of cardiac output and aortic blood flow acceleration, cardiac performance in the absence of beta-blockade was markedly impaired during steady-state anesthesia, compared with corresponding values in normal dogs. Practolol (2.0 mg/kg) administered during anesthesia induced no significant circulatory change other than a 14 per cent decrease in heart rate and a 25 per cent increase in strode volum. Propranolol (0.3 mg/kg) caused a comparable reduction of heart rate, but significantly reduced cardiac output (-27 per cent), aortic blood flow acceleration (-26 per cent), and peak LV power (-19 per cent), and increased systemic vascular resistance (+49 per cent). The two drugs caused comparable shifts of the isoproterenol dose-response curve during anesthesia. Graduated blood loss during anesthesia, to a total of 25 per cent of blood volume, caused consistent circulatory changes (decreased mean arterial pressure cardiac output, peak LV power, LV minute work) that were essentially similar before and after beta-receptor blockade with either propranolol or practolol. The positive inotropic effect of calcium gluconate during halothane anesthesia was significantly reduced following either propranolol or practolol, but the hemodynamic responses to changes of systemic vascular resistance induced with acetylcholine or phenylephrine were not modified by beta-receptor blockade.

  3. Blockade of NMDA receptors prevents analgesic tolerance to repeated transcutaneous electrical nerve stimulation (TENS) in rats

    PubMed Central

    Hingne, Priyanka M.; Sluka, Kathleen A.

    2008-01-01

    Repeated daily application transcutaneous electrical nerve stimulation (TENS) results in tolerance, at spinal opioid receptors, to the anti-hyperalgesia produced by TENS. Since N-Methyl-D-Aspartate (NMDA) receptor antagonists prevent analgesic tolerance to opioid agonists we hypothesized that blockade of NMDA receptors will prevent tolerance to TENS. In rats with knee joint inflammation, TENS was applied for 20 minute daily at high frequency (100 Hz), low frequency (4 Hz), or sham TENS. Rats were treated with the NMDA antagonist MK-801 (0.01 mg/kg-0.1 mg/kg) or vehicle daily before TENS. Paw withdrawal thresholds were tested before and after inflammation, and before and after TENS treatment for 4 days. On day 1 TENS reversed the decreased mechanical withdrawal threshold induced by joint inflammation. On day 4 TENS had no effect on the decreased withdrawal threshold in the group treated with vehicle demonstrating development of tolerance. However, in the group treated with 0.1 mg/kg MK-801, TENS significantly reversed the mechanical withdrawal thresholds on day 4 demonstrating that tolerance did not develop. Vehicle treated animals developed cross-tolerance at spinal opioid receptors. Treatment with MK-801 reversed this cross-tolerance at spinal opioid receptors. In summary, blockade of NMDA receptors prevents analgesic tolerance to daily TENS by preventing tolerance at spinal opioid receptors. Perspective Tolerance observed to the clinical treatment of TENS could be prevented by administration of pharmaceutical agents with NMDA receptors activity such as ketamine or dextromethorphan. PMID:18061543

  4. Down-regulation of tumor necrosis factor receptors by blockade of mitochondrial respiration.

    PubMed

    Sánchez-Alcázar, J A; Hernández, I; De la Torre, M P; García, I; Santiago, E; Muñoz-Yagüe, M T; Solís-Herruzo, J A

    1995-10-13

    We have studied the effect of blockade of mitochondrial respiration on the binding of human 125I-TNF alpha to L929 cell receptors. Specific TNF alpha binding was decreased to about 20-40% of controls by blocking mitochondrial respiration. This effect was dose- and time-related and was observed independently of the level at which the respiration was blocked (respiratory chain, proton backflow, ATPase, anaerobiosis). This blockade had no effect on the half-life of the specific TNF alpha binding, the internalization or degradation of TNF alpha-receptor complexes, or the number of TNF alpha-binding sites. Scatchard analysis of TNF alpha binding data indicated a 2-4-fold decrease in the affinity of these binding sites. These effects did not appear to be related to the protein kinase C activity or to reactive oxygen radicals, since they were not antagonized by pretreatment of cells with oxygen radical scavengers, deferoxamine, or inhibitors of protein kinase C. Decrease in TNF alpha binding capacity correlated significantly with cellular ATP content (r = 0.94; p < 0.01) and with the cytocidal activity of TNF alpha against L929 cells. These findings suggest that blockade of mitochondrial respiration down-regulates the binding of TNF alpha to cells, most likely by changing the affinity of receptors for this cytokine. This down-regulation may increase the resistance of cells to TNF alpha cytotoxicity.

  5. Sympathetic neural activation evoked by mu-receptor blockade in patients addicted to opioids is abolished by intravenous clonidine.

    PubMed

    Kienbaum, Peter; Heuter, Thorsten; Michel, Martin C; Scherbaum, Norbert; Gastpar, Markus; Peters, Jürgen

    2002-02-01

    Mu-opioid receptor blockade by naloxone administered for acute detoxification in patients addicted to opioids markedly increases catecholamine plasma concentrations, muscle sympathetic activity (MSA), and is associated with cardiovascular stimulation despite general anesthesia. The current authors tested the hypothesis that the alpha2-adrenoceptor agonist clonidine (1) attenuates increased MSA during mu-opioid receptor blockade for detoxification, and (2) prevents cardiovascular activation when given before detoxification. Fourteen mono-opioid addicted patients received naloxone during propofol anesthesia. Clonidine (10 microg x kg(-1) administered over 5 min + 5 microg x kg(-1) x h(-1) intravenous) was infused either before (n = 6) or after (n = 6) naloxone administration. Two patients without immediate clonidine administration occurring after naloxone administration served as time controls. Muscle sympathetic activity (n = 8) in the peroneal nerve, catecholamine plasma concentrations (n = 14), arterial blood pressure, and heart rate were assessed in awake patients, during propofol anesthesia before and after mu-opioid receptor blockade, and after clonidine administration. Mu-receptor blockade markedly increased MSA from a low activity (burst frequency: from 2 burst/min +/- 1 to 24 +/- 8, means +/- SD). Similarly, norepinephrine (41 pg/ml +/- 37 to 321 +/- 134) and epinephrine plasma concentration (13 pg/ml +/- 6 to 627 +/- 146) significantly increased, and were associated with, increased arterial blood pressure and heart rate. Clonidine immediately abolished both increased MSA (P < 0.001) and catecholamine plasma concentrations (P < 0.001). When clonidine was given before mu-opioid receptor blockade, catecholamine plasma concentrations and hemodynamic variables did not change. Administration of the alpha2-adrenoceptor agonist clonidine decreases both increased MSA and catecholamine plasma concentrations observed after mu-opioid receptor blockade for

  6. Activity blockade and GABAA receptor blockade produce synaptic scaling through chloride accumulation in embryonic spinal motoneurons and interneurons.

    PubMed

    Lindsly, Casie; Gonzalez-Islas, Carlos; Wenner, Peter

    2014-01-01

    Synaptic scaling represents a process whereby the distribution of a cell's synaptic strengths are altered by a multiplicative scaling factor. Scaling is thought to be a compensatory response that homeostatically controls spiking activity levels in the cell or network. Previously, we observed GABAergic synaptic scaling in embryonic spinal motoneurons following in vivo blockade of either spiking activity or GABAA receptors (GABAARs). We had determined that activity blockade triggered upward GABAergic scaling through chloride accumulation, thus increasing the driving force for these currents. To determine whether chloride accumulation also underlies GABAergic scaling following GABAAR blockade we have developed a new technique. We expressed a genetically encoded chloride-indicator, Clomeleon, in the embryonic chick spinal cord, which provides a non-invasive fast measure of intracellular chloride. Using this technique we now show that chloride accumulation underlies GABAergic scaling following blockade of either spiking activity or the GABAAR. The finding that GABAAR blockade and activity blockade trigger scaling via a common mechanism supports our hypothesis that activity blockade reduces GABAAR activation, which triggers synaptic scaling. In addition, Clomeleon imaging demonstrated the time course and widespread nature of GABAergic scaling through chloride accumulation, as it was also observed in spinal interneurons. This suggests that homeostatic scaling via chloride accumulation is a common feature in many neuronal classes within the embryonic spinal cord and opens the possibility that this process may occur throughout the nervous system at early stages of development.

  7. Recovery of network-driven glutamatergic activity in rat hippocampal neurons during chronic glutamate receptor blockade.

    PubMed

    Leininger, Eric; Belousov, Andrei B

    2009-01-28

    Previous studies indicated that a long-term decrease in the activity of ionotropic glutamate receptors induces cholinergic activity in rat and mouse hypothalamic neuronal cultures. Here we studied whether a prolonged inactivation of ionotropic glutamate receptors also induces cholinergic activity in hippocampal neurons. Receptor activity was chronically suppressed in rat hippocampal primary neuronal cultures with two proportionally increasing sets of concentrations of NMDA plus non-NMDA receptor antagonists: 100 microM/10 microM AP5/CNQX (1X cultures) and 200 microM/20 microM AP5/CNQX (2X cultures). Using calcium imaging we demonstrate that cholinergic activity does not develop in these cultures. Instead, network-driven glutamate-dependent activity, that normally is detected in hyper-excitable conditions, reappears in each culture group in the presence of these antagonists and can be reversibly suppressed by higher concentrations of AP5/CNQX. This activity is mediated by non-NMDA receptors and is modulated by NMDA receptors. Further, non-NMDA receptors, the general level of glutamate receptor activity and CaMK-dependent signaling are critical for development of this network-driven glutamatergic activity in the presence of receptor antagonists. Using electrophysiology, western blotting and calcium imaging we show that some neuronal parameters are either reduced or not affected by chronic glutamate receptor blockade. However, other parameters (including neuronal excitability, mEPSC frequency, and expression of GluR1, NR1 and betaCaMKII) become up-regulated and, in some cases, proportionally between the non-treated, 1X and 2X cultures. Our data suggest recovery of the network-driven glutamatergic activity after chronic glutamate receptor blockade. This recovery may represent a form of neuronal plasticity that compensates for the prolonged suppression of the activity of glutamate receptors.

  8. Effect of {beta}{sub 1} adrenergic receptor blockade on myocardial blood flow and vasodilatory capacity

    SciTech Connect

    Boettcher, M.; Czernin, J.; Sun, K.

    1997-03-01

    The {beta}{sub 1} receptor blockade reduces cardiac work and may thereby lower myocardial blood flow (MBF) at rest. The effect of {beta}{sub 1} receptor blockade on hyperemic MBF is unknown. To evaluate the effect of selective {beta}{sub 1} receptor blockade on MBF at rest and during dipyridamole induced hyperemia, 10 healthy volunteers (8 men, 2 women, mean age 24 {+-} 5 yr) were studied using {sup 13}N-ammonia PET (two-compartment model) under control conditions and again during metoprolol (50 mg orally 12 hr and 1 hr before the study). The resting rate pressure product (6628 {+-} 504 versus 5225 {+-} 807) and heart rate (63 {+-} 6-54 {plus_minus} 5 bpm) declined during metoprolol (p < 0.05). Similarly, heart rate and rate pressure product declined from the baseline dipyridamole study to dipyridamole plus metoprolol (p < 0.05). Resting MBF declined in proportion to cardiac work by approximately 20% from 0.61 {+-} 0.09-0.51 {+-} 0.10 ml/g/min (p < 0.05). In contrast, hyperemic MBF increased when metoprolol was added to dipyridamole (1.86 {plus_minus} 0.27 {+-} 0.45 ml/g/min; p<0.05). The decrease in resting MBF together with the increase in hyperemic MBF resulted in a significant increase in the myocardial flow reserve during metoprolol (3.14 {+-} 0.80-4.61 {+-} 0.68; p<0.01). The {beta}{sub 1} receptor blockade increases coronary vasodilatory capacity and myocardial flow reserve. However, the mechanisms accounting for this finding remain uncertain. 32 refs., 2 figs., 2 tabs.

  9. Blockade of Insect Odorant Receptor Currents by Amiloride Derivatives

    PubMed Central

    2013-01-01

    Insect odorant receptors (ORs) function as heteromeric odorant-gated ion channels consisting of a conserved coreceptor, Orco, and an odorant-sensitive tuning subunit. Although some OR modulators have been identified, an extended library of pharmacological tools is currently lacking and would aid in furthering our understanding of insect OR complexes. We now demonstrate that amiloride and several derivatives, which have been extensively used as blockers for various ion channels and transporters, also block odorant-gated currents from 2 OR complexes from the malaria vector mosquito Anopheles gambiae. In addition, both heteromeric and homomeric ORs were susceptible to amiloride blockade when activated by VUAA1, an agonist that targets the Orco channel subunit. Amiloride derivatives therefore represent a valuable class of channel blockers that can be used to investigate the pharmacological and biophysical properties of insect OR function. PMID:23292750

  10. Influence of antiseptics on microcirculation after neuronal and receptor blockade.

    PubMed

    Goertz, Ole; Hirsch, Tobias; Ring, Andrej; Muehlberger, Thomas; Steinau, Hans U; Tilkorn, Daniel; Lehnhardt, Marcus; Homann, Heinz H

    2011-08-01

    The topical application of the antiseptics octenidine and polyhexanide on wounds seems to improve microcirculation. These two antiseptics were tested in combination with neuronal inhibition and sympathethic receptor blockade to verify these findings, explore the influence of β blockers on these microcirculative effects, and find out the principle of operation. Investigations were carried out on a standardised cremaster muscle model in rats (n = 66). The tested antiseptics, octenidine and polyhexanide were investigated alone (n = 12) and in combination with bupivacaine (n = 12), metoprolol (n = 12), phentolamine (n = 12) and surgical denervation (n = 12). Physiological saline was used for control (n = 6). The arteriolar diameter and functional capillary density (FCD) were investigated via trans-illumination microscopy before, as well as 60 and 120 minutes after application. Polyhexanide caused a significant increase in arteriolar diameter (86·5 ± 3·8 µm versus 100·0 ± 3·6 µm) and, like octenidine (7·2 ± 0·7 n/0·22 mm(2) versus 11·6 ± 0·6 n/0·22 mm(2) ), in FCD (9·2 ± 0·5 versus 12·6 ± 0·9) as well. When the antiseptics are used in combination with bupivacaine, metoprolol, phentolamine or surgical sympathectomy, these effects were eliminated or inverted. Assessing the results of the different blockades in combination with polyhexanide, we surmise that the antiseptic polyhexanide acts on the microcirculation mainly by blocking α receptors. This study shows that polyhexanide and octenidine improve muscular perfusion. Interestingly, the benefit of polyhexanide and octenidine on muscular perfusion is eliminated when the antiseptics are combined with other vasoactive agents, especially β blockers. © 2011 The Authors. © 2011 Blackwell Publishing Ltd and Medicalhelplines.com Inc.

  11. Differential effects of M1 muscarinic receptor blockade and nicotinic receptor blockade in the dorsomedial striatum on response reversal learning

    PubMed Central

    Tzavos, Arianna; Jih, Jane; Ragozzino, Michael E.

    2011-01-01

    The present studies determined whether blockade of M1-like muscarinic or nicotinic cholinergic receptors in the dorsomedial striatum affects acquisition or reversal learning of a response discrimination. Testing occurred in a modified cross-maze across two consecutive sessions. In the acquisition phase, a rat learned to turn to the left or to the right. In the reversal learning phase, a rat learned to turn in the opposite direction as required during acquisition. Experiment 1 investigated the effects of the M1-like muscarinic receptor antagonist, pirenzepine infused into the dorsomedial striatum on acquisition and reversal learning. Experiment 2 examined the effects of the nicotinic cholinergic antagonist, mecamylamine injected into the dorsomedial striatum on acquisition and reversal learning. Bilateral injections of pirenzepine at 10 µg, but not 1 µg, selectively impaired reversal learning. Analysis of the errors indicated that pirenzepine treatment did not impair the initial shift, but increased reversions back to the original response choice following the initial shift. Bilateral injections of mecamylamine, 6 or 18 µg, did not affect acquisition or reversal learning. The results suggest that activation of M1 muscarinic cholinergic receptors, but not nicotinic cholinergic receptors, in the dorsomedial striatum is important for facilitating the flexible shifting of response patterns. PMID:15302131

  12. Endothelin A-receptor blockade in experimental diabetes improves glucose balance and gastrointestinal function.

    PubMed

    Balsiger, Bruno; Rickenbacher, Andreas; Boden, Penelope Jane; Biecker, Erwin; Tsui, Janice; Dashwood, Michael; Reichen, Jürg; Shaw, Sidney George

    2002-08-01

    Secondary complications of diabetes mellitus often involve gastrointestinal dysfunction. In the experimental Goto Kakizaki rat, a model of Type II diabetes, hyperglycaemia and reduced glucose clearance is associated with elevated plasma endothelin (ET)-1 levels and selective decreases in nitric oxide synthase in circular muscle, longitudinal muscle and neuronal elements of the gastrointestinal tract. Functionally, this is accompanied by decreased nitrergic relaxatory responses of jejunal longitudinal muscle to tetrodotoxin-sensitive electrical field stimulation. Long-term treatment with a selective ET A-type receptor antagonist, markedly reduced hyperglycaemia and restored plasma glucose clearance rates towards normal. This was associated with a restoration of N(G)-nitro-L-arginine methyl ester-sensitive relaxatory responses of jejunal longitudinal muscle to electrical field stimulation. The results indicate that beneficial effects of ETA receptor blockade on gastrointestinal function may result from an improvement in insulin sensitivity with concomitant reduction of the severity of hyperglycaemia. ETA receptor blockade may represent a new therapeutic principle for improving glucose tolerance in Type II diabetes and could be beneficial in alleviating or preventing hyperglycaemia-related secondary complications in this condition.

  13. IL-7 receptor blockade following T cell depletion promotes long-term allograft survival

    PubMed Central

    Mai, Hoa-Le; Boeffard, Françoise; Longis, Julie; Danger, Richard; Martinet, Bernard; Haspot, Fabienne; Vanhove, Bernard; Brouard, Sophie; Soulillou, Jean-Paul

    2014-01-01

    T cell depletion is commonly used in organ transplantation for immunosuppression; however, a restoration of T cell homeostasis following depletion leads to increased memory T cells, which may promote transplant rejection. The cytokine IL-7 is important for controlling lymphopoiesis under both normal and lymphopenic conditions. Here, we investigated whether blocking IL-7 signaling with a mAb that targets IL-7 receptor α (IL-7Rα) alone or following T cell depletion confers an advantage for allograft survival in murine transplant models. We found that IL-7R blockade alone induced indefinite pancreatic islet allograft survival if anti–IL-7R treatment was started 3 weeks before graft. IL-7R blockade following anti-CD4– and anti-CD8–mediated T cell depletion markedly prolonged skin allograft survival. Furthermore, IL-7 inhibition in combination with T cell depletion synergized with either CTLA-4Ig administration or suboptimal doses of tacrolimus to induce long-term skin graft acceptance in this stringent transplant model. Together, these therapies inhibited T cell reconstitution, decreased memory T cell numbers, increased the relative frequency of Tregs, and abrogated both cellular and humoral alloimmune responses. Our data suggest that IL-7R blockade following T cell depletion has potential as a robust, immunosuppressive therapy in transplantation. PMID:24569454

  14. Effect of H1- and H2-histamine receptor blockade on postexercise insulin sensitivity

    PubMed Central

    Pellinger, Thomas K; Dumke, Breanna R; Halliwill, John R

    2013-01-01

    Following a bout of dynamic exercise, humans experience sustained postexercise vasodilatation in the previously exercised skeletal muscle which is mediated by activation of histamine (H1 and H2) receptors. Skeletal muscle glucose uptake is also enhanced following dynamic exercise. Our aim was to determine if blunting the vasodilatation during recovery from exercise would have an adverse effect on blood glucose regulation. Thus, we tested the hypothesis that insulin sensitivity following exercise would be reduced with H1- and H2-receptor blockade versus control (no blockade). We studied 20 healthy young subjects (12 exercise; eight nonexercise sham) on randomized control and H1- and H2-receptor blockade (fexofenadine and ranitidine) days. Following 60 min of upright cycling at 60% VO2 peak or nonexercise sham, subjects consumed an oral glucose tolerance beverage (1.0 g/kg). Blood glucose was determined from “arterialized” blood samples (heated hand vein). Postexercise whole-body insulin sensitivity (Matsuda insulin sensitivity index) was reduced 25% with H1- and H2-receptor blockade (P < 0.05), whereas insulin sensitivity was not affected by histamine receptor blockade in the sham trials. These results indicate that insulin sensitivity following exercise is blunted by H1- and H2-receptor blockade and suggest that postexercise H1- and H2-receptor–mediated skeletal muscle vasodilatation benefits glucose regulation in healthy humans. PMID:24303118

  15. Add-on angiotensin receptor blockade with maximized ACE inhibition.

    PubMed

    Agarwal, R

    2001-06-01

    cardiac output. However, there was a mean 14% increase (95% CI, 3 to 26%, P = 0.017) in GFR attributable to losartan therapy. A concomitant fall in plasma renin activity by 32% was seen (95% CI, -15%, - 45%, P = 0.002). No hyperkalemia, hypotension, or acute renal failure occurred in the trial. These results were not attributable to sequence or carryover effects. Add-on losartan therapy did not improve proteinuria or ABP over one month of add on therapy. Improvement of GFR and fall in plasma renin activity suggest that renal hemodynamic and endocrine changes are more sensitive measures of AT1 receptor blockade. Whether add-on AT1 receptor blockade causes antiproteinuric effects or long-term renal protection requires larger and longer prospective, randomized controlled trials.

  16. Partial neuromuscular blockade in humans enhances muscle blood flow during exercise independently of muscle oxygen uptake and acetylcholine receptor blockade.

    PubMed

    Hellsten, Ylva; Krustrup, Peter; Iaia, F Marcello; Secher, Niels H; Bangsbo, Jens

    2009-04-01

    This study examined the role of acetylcholine for skeletal muscle blood flow during exercise by use of the competitive neuromuscular blocking agent cisatracurium in combination with the acetylcholine receptor blocker glycopyrrone. Nine healthy male subjects performed a 10-min bout of one-legged knee-extensor exercise (18 W) during control conditions and with cisatracurium blockade, as well as with cisatracurium blockade with prior glycopyrrone infusion. Thigh blood flow and vascular conductance in control and with cisatracurium infusion were similar at rest and during passive movement of the leg, but higher (P < 0.05) during exercise with cisatracurium than in control (3.83 +/- 0.42 vs. 2.78 +/- 0.21 l/min and 26.9 +/- 3.4 vs. 21.8 +/- 2.0 ml.min(-1).mmHg(-1) at the end of exercise). Thigh oxygen uptake was similar in control and with cisatracurium infusion both at rest and during exercise, being 354 +/- 33 and 406 +/- 34 ml/min, at the end of exercise. Combined infusion of cisatracurium and glycopyrrone caused a similar increase in blood flow as cisatracurium infusion alone. The current results demonstrate that neuromuscular blockade leads to enhanced thigh blood flow and vascular conductance during exercise, events that are not associated with either acetylcholine or an increased oxygen demand. The results do not support an essential role for acetylcholine, released form the neuromuscular junction, in exercise hyperemia or for the enhanced blood flow during neuromuscular blockade. The enhanced exercise hyperemia during partial neuromuscular blockade may be related to a greater recruitment of fast-twitch muscle fibers.

  17. initial angiotensin receptor blockade-induced decrease in albuminuria is associated with long-term renal outcome in type 2 diabetic patients with microalbuminuria: a post hoc analysis of the IRMA-2 trial.

    PubMed

    Hellemons, Merel E; Persson, Frederik; Bakker, Stephan J L; Rossing, Peter; Parving, Hans-Henrik; De Zeeuw, Dick; Lambers Heerspink, Hiddo J

    2011-09-01

    We aimed to investigate the individual impact of initial responses in urinary albumin excretion (UAE) and systolic blood pressure (SBP) to angiotensin II receptor blocker (ARB) treatment on long-term renal outcome in patients with type 2 diabetes and microalbuminuria. In a post hoc analysis of the Irbesartan in Patients with Type 2 Diabetes and Microalbuminuria (IRMA)-2 trial we first assessed the individual variability in UAE and SBP response (0-6 months) in 531 subjects. Subsequently, we analyzed the individual effect of both response parameters on renal outcome defined as change in estimated glomerular filtration rate (eGFR) during 2 years of follow-up. The median reductions in UAE and SBP in the population were -18% and -11 mmHg, respectively. In irbesartan-treated patients, 85 (24.4%) had a robust (>median) reduction in UAE but not in SBP (discordant SBP response) and 67 (19.3%) had a robust (>median) reduction in SBP but not in UAE (discordant UAE response). The degree of reduction in UAE was independently associated with the rate of eGFR decline (P = 0.0037). SBP showed a similar trend (P = 0.087). The relation between a larger UAE reduction and a slower rate of renal function decline was present in both cohorts with a SBP change above and below the median. Within an individual, UAE response to ARB therapy may be discordant from SBP response. The initial change in UAE was independently associated with eGFR slope; the more UAE reduction the less eGFR decline, irrespective of the SBP change. These results suggest that in microalbuminuric patients with type 2 diabetes, UAE should be monitored after initiation of therapy and a separate target for renoprotective therapy.

  18. Ventral Midbrain NMDA Receptor Blockade: From Enhanced Reward and Dopamine Inactivation

    PubMed Central

    Hernandez, Giovanni; Cossette, Marie-Pierre; Shizgal, Peter; Rompré, Pierre-Paul

    2016-01-01

    Glutamate stimulates ventral midbrain (VM) N-Methyl-D-Aspartate receptors (NMDAR) to initiate dopamine (DA) burst firing activity, a mode of discharge associated with enhanced DA release and reward. Blockade of VM NMDAR, however, enhances brain stimulation reward (BSR), the results can be explained by a reduction in the inhibitory drive on DA neurons that is also under the control of glutamate. In this study, we used fast-scan cyclic voltammetry (FSCV) in anesthetized animals to determine whether this enhancement is associated with a change in phasic DA release in the nucleus accumbens. Rats were implanted with a stimulation electrode in the dorsal-raphe (DR) and bilateral cannulae above the VM and trained to self-administer trains of electrical stimulation. The curve-shift method was used to evaluate the effect of a single dose (0.825 nmol/0.5 μl/side) of the NMDAR antagonist, (2R,4S)-4-(3-Phosphopropyl)-2-piperidinecarboxylic acid (PPPA), on reward. These animals were then anesthetized and DA release was measured during delivery of electrical stimulation before and after VM microinjection of the vehicle followed by PPPA. As expected, phasic DA release and operant responding depended similarly on the frequency of rewarding electrical stimulation. As anticipated, PPPA produced a significant reward enhancement. Unexpectedly, PPPA produced a decrease in the magnitude of DA transients at all tested frequencies. To test whether this decrease resulted from excessive activation of DA neurons, we injected apomorphine 20 min after PPPA microinjection. At a dose (100 μg s.c.) sufficient to reduce DA firing under control conditions, apomorphine restored electrical stimulation-induced DA transients. These findings show that combined electrical stimulation and VM NMDARs blockade induce DA inactivation, an effect that indirectly demonstrates that VM NMDARs blockade enhances reward by potentiating stimulation-induced excitation in the mesoaccumbens DA pathway. PMID:27616984

  19. Adenosine A2B receptor blockade slows growth of bladder and breast tumors.

    PubMed

    Cekic, Caglar; Sag, Duygu; Li, Yuesheng; Theodorescu, Dan; Strieter, Robert M; Linden, Joel

    2012-01-01

    The accumulation of high levels of adenosine in tumors activates A(2A) and A(2B) receptors on immune cells and inhibits their ability to suppress tumor growth. Deletion of adenosine A(2A) receptors (A(2A)ARs) has been reported to activate antitumor T cells, stimulate dendritic cell (DC) function, and inhibit angiogenesis. In this study, we evaluated the effects of intermittent intratumor injection of a nonselective adenosine receptor antagonist, aminophylline (AMO; theophylline ethylenediamine) and, for the first time to our knowledge, a selective A(2B)AR antagonist, ATL801. AMO and ATL801 slowed the growth of MB49 bladder and 4T1 breast tumors in syngeneic mice and reduced by 85% metastasizes of breast cancer cells from mammary fat to lung. Based on experiments with A(2A)AR(-/-) or adenosine A(2B) receptor(-/-) mice, the effect of AMO injection was unexpectedly attributed to A(2B)AR and not to A(2A)AR blockade. AMO and ATL801 significantly increased tumor levels of IFN-γ and the IFN-inducible chemokine CXCL10, which is a ligand for CXCR3. This was associated with an increase in activated tumor-infiltrating CXCR3(+) T cells and a decrease in endothelial cell precursors within tumors. Tumor growth inhibition by AMO or ATL801 was eliminated in CXCR3(-/-) mice and RAG1(-/-) mice that lack mature T cells. In RAG1(-/-) mice, A(2B)AR deletion enhanced CD86 expression on CD11b(-) DCs. Bone marrow chimera experiments demonstrated that CXCR3 and A(2B)AR expression on bone marrow cells is required for the antitumor effects of AMO. The data suggest that blockade of A(2B)ARs enhances DC activation and CXCR3-dependent antitumor responses.

  20. Remodeling of striatal NMDA receptors by chronic A(2A) receptor blockade in Huntington's disease mice.

    PubMed

    Martire, Alberto; Ferrante, Antonella; Potenza, Rosa Luisa; Armida, Monica; Ferretti, Roberta; Pézzola, Antonella; Domenici, Maria Rosaria; Popoli, Patrizia

    2010-01-01

    Excitotoxicity plays a major role in the pathogenesis of Huntington disease (HD), a fatal neurodegenerative disorder. Adenosine A(2A) receptors (A(2A)Rs) modulate excitotoxicity and have been suggested to play a pathogenetic role in HD. The main aim of this study was to evaluate the effect of A(2A)R blockade on the expression and functions of NMDA receptors in the striatum of HD mice (R6/2). We found that 3 weeks' treatment with SCH 58261 (0.01 mg/kg/day i.p. from the 8th week of age) modified NR1 and NR2A/NR2B expression in the striatum of R6/2 (Western blotting) while had no effect on NMDA-induced toxicity in corticostriatal slices (electrophysiological experiments). In conclusion, in vivo A(2A)R blockade induced a remodeling of NMDA receptors in the striatum of HD mice. Even though the functional relevance of the above effect remains to be fully elucidated, these results add further evidence to the modulatory role of A(2A)Rs in HD.

  1. Endothelin A-receptor blockade worsens endotoxin-induced hepatic microcirculatory changes and necrosis.

    PubMed

    Nishida, T; Huang, T P; Seiyama, A; Hamada, E; Kamiike, W; Ueshima, S; Kazuo, H; Matsuda, H

    1998-08-01

    Endothelin 1 is considered to be an important regulator of sinusoidal blood flow and increases during endotoxemia. The purpose of this study was to investigate the role of endothelin 1 in hepatic microcirculation, oxygen transport, and liver injury during endotoxemia. Male Sprague-Dawley rats were continuously infused with 2.5 mL/h of saline, 0.8 mg . kg-1 . h-1 of lipopolysaccharide (LPS), 3 mg . kg-1 . h-1 of BQ-485, an endothelin A-receptor antagonist, or LPS plus BQ-485 for 7 hours. BQ-485 infusion had no significant effect on hepatic microcirculation and liver injury. LPS increased the plasma levels of aspartate aminotransferase (AST) and total bilirubin and decreased the hepatic adenosine triphosphate (ATP) level and bile flow rate. LPS + BQ-485 infusion further increased the plasma levels of AST and total bilirubin and decreased the bile flow rate and the hepatic ATP level. Dual-spot microspectroscopy revealed mild decreases in sinusoidal erythrocyte velocity and oxygen transport in the LPS group and profound decreases in these parameters in the LPS + BQ-485 group. Histological examinations revealed massive necrotic changes in the pericentral regions of the LPS + BQ-485 group. These results suggest that blockade of endothelin A receptors disturbs hepatic microcirculation and oxygen transport and aggravates the necrotic injury induced by endotoxin.

  2. Effect of mineralocorticoid receptor blockade on hippocampal-dependent memory in adults with obesity.

    PubMed

    Rotenstein, Lisa S; Sheridan, Margaret; Garg, Rajesh; Adler, Gail K

    2015-06-01

    The hippocampus is crucial for paired-associate learning. Obesity is associated with increased mineralocorticoid receptor (MR) activity in peripheral and possibly central tissues, decreased hippocampal size in humans, and impaired hippocampal learning in rodents. The MR is expressed in hippocampal neurons, and MR blockade improves hippocampal learning in obese animals. The goal of the study was to determine whether MR blockade would modulate paired-associate learning in men and women with obesity. Men and women ages 20-61 years with BMI between 30-45 kg/m(2) were randomly assigned to placebo (n = 11; 7 women) or 50 mg spironolactone daily (n = 12; 7 women) for six weeks. At baseline and post-treatment, subjects underwent a clinical and hormonal evaluation. They also underwent a computerized task that assesses paired-associate learning and has been shown by functional magnetic resonance imaging to activate the hippocampus. In an ANCOVA model that adjusted for baseline paired-associate learning, age, and race, spironolactone treatment was associated with a significant (P = 0.043) improvement in hippocampal memory as compared to placebo treatment. Our findings demonstrate, for the first time, that blocking MR with chronic, low-dose spironolactone treatment improves paired-associate learning in individuals with obesity, suggesting that MR activation contributes to hippocampal memory modulation in humans. © 2015 The Obesity Society.

  3. Genetic deletion and pharmacological blockade of CB1 receptors modulates anxiety in the shock-probe burying test.

    PubMed

    Degroot, Aldemar; Nomikos, George G

    2004-08-01

    Cannabinoids affect various behavioral processes, including emotion, learning and memory, which may be specifically regulated through the CB1 receptors. The exact role CB1 receptors play in anxiety remains unclear. Both genetic and pharmacological blockade of CB1 receptors have produced inconsistent effects on anxiety. However, these studies examined passive avoidance as an index of anxiety. In the present study, both active and passive avoidance were examined using the shock-probe burying test while CB1 receptors were blocked genetically or pharmacologically. In the shock-probe burying test, anxiety is reflected by increased burying (increased active avoidance) and increased freezing (increased passive avoidance). In addition, probe-contacts may reflect cognitive performance and/or passive avoidance. As there have been few studies examining mouse behavior in the shock-probe burying test, experiment 1 was designed to pharmacologically validate this model in mice. Our results indicated that administration (i.p.) of chlordiazepoxide (4 mg/kg) or FG7412 (5 mg/kg) decreased and increased burying behavior, respectively, without affecting freezing or the number of probe contacts. Experiments 2 and 3 showed that both CB1 knockout mice and mice injected (i.p.) with 3 or 10 mg/kg, but not 1 mg/kg, of the CB1 receptor antagonist SR141716A had lower burying scores, fewer contacts with the probe and similar freezing times compared with wild-type mice and mice injected with vehicle (experiments 2 and 3). Collectively, these results suggest that CB1 receptor blockade reduces some, but not all, aspects of anxiety. The decrease in probe contacts induced by CB1 receptor blockade may be due to enhanced cognition.

  4. Telmisartan ameliorates glutamate-induced neurotoxicity: roles of AT1 receptor blockade and PPARγ activation

    PubMed Central

    Wang, Juan; Pang, Tao; Hafko, Roman; Benicky, Julius; Sanchez-Lemus, Enrique; Saavedra, Juan M.

    2014-01-01

    Sartans (Angiotensin II AT1 Receptor Blockers, ARBs) are powerful neuroprotective agents in vivo and protect against IL-1β neurotoxicity in vitro. The purpose of this research was to determine the extent of sartan neuroprotection against glutamate excitotoxicity, a common cause of neuronal injury and apoptosis. The results show that sartans are neuroprotective, significantly reducing glutamate-induced neuronal injury and apoptosis in cultured rat primary cerebellar granule cells (CGCs). Telmisartan was the most potent sartan studied, with an order of potency telmisartan > candesartan > losartan > valsartan. Mechanisms involved reduction of pro-apoptotic caspase-3 activation, protection of the survival PI3K/Akt/GSK-3β pathway, and prevention of glutamate-induced ERK1/2 activation. NMDA receptor stimulation was essential for glutamate-induced cell injury and apoptosis. Participation of AT1A receptor was supported by glutamate-induced upregulation of AT1A gene expression and AT1 receptor binding. Conversely, AT1B or AT2 receptor played no role. Glutamate-induced neuronal injury and the neuroprotective effect of telmisartan were decreased, but not abolished, in CGCs obtained from AT1A knock-out mice. This indicates that although AT1 receptors are necessary for glutamate to exert its full neurotoxic potential, part of the neuroprotective effect of telmisartan is independent of AT1 receptor blockade. PPARγ activation was also involved in the neuroprotective effects of telmisartan, as telmisartan enhanced PPARγ nuclear translocation, and the PPARγ antagonist GW9662 partially reversed the neuroprotective effects of telmisartan. The present results substantiate the therapeutic use of sartans, in particular telmisartan, in neurodegenerative diseases and traumatic brain disorders where glutamate neurotoxicity plays a significant role. PMID:24316465

  5. Telmisartan ameliorates glutamate-induced neurotoxicity: roles of AT(1) receptor blockade and PPARγ activation.

    PubMed

    Wang, Juan; Pang, Tao; Hafko, Roman; Benicky, Julius; Sanchez-Lemus, Enrique; Saavedra, Juan M

    2014-04-01

    Sartans (Angiotensin II AT(1) Receptor Blockers, ARBs) are powerful neuroprotective agents in vivo and protect against IL-1β neurotoxicity in vitro. The purpose of this research was to determine the extent of sartan neuroprotection against glutamate excitotoxicity, a common cause of neuronal injury and apoptosis. The results show that sartans are neuroprotective, significantly reducing glutamate-induced neuronal injury and apoptosis in cultured rat primary cerebellar granule cells (CGCs). Telmisartan was the most potent sartan studied, with an order of potency telmisartan > candesartan > losartan > valsartan. Mechanisms involved reduction of pro-apoptotic caspase-3 activation, protection of the survival PI3K/Akt/GSK-3β pathway and prevention of glutamate-induced ERK1/2 activation. NMDA receptor stimulation was essential for glutamate-induced cell injury and apoptosis. Participation of AT(1A) receptor was supported by glutamate-induced upregulation of AT(1A) gene expression and AT(1) receptor binding. Conversely, AT(1B) or AT(2) receptors played no role. Glutamate-induced neuronal injury and the neuroprotective effect of telmisartan were decreased, but not abolished, in CGCs obtained from AT(1A) knock-out mice. This indicates that although AT(1) receptors are necessary for glutamate to exert its full neurotoxic potential, part of the neuroprotective effect of telmisartan is independent of AT(1) receptor blockade. PPARγ activation was also involved in the neuroprotective effects of telmisartan, as telmisartan enhanced PPARγ nuclear translocation and the PPARγ antagonist GW9662 partially reversed the neuroprotective effects of telmisartan. The present results substantiate the therapeutic use of sartans, in particular telmisartan, in neurodegenerative diseases and traumatic brain disorders where glutamate neurotoxicity plays a significant role. Published by Elsevier Ltd.

  6. Cerebrocortical and medullary blood flow changes after general opiate receptor blockade during hemorrhagic shock in cats.

    PubMed

    Komjáti, K; Sandor, P; Sandor, N; Szirmai, L; H-Velkei, M; Kovach, A G

    1997-04-01

    The effect of centrally induced opiate receptor blockade on regional cerebral blood flow (rCBF) was studied in anesthetized, ventilated cats during the course of hemorrhagic shock. The blood flow of the medulla and the parietal cortex was measured with the H2-gas clearance technique. Hemorrhagic shock was produced by lowering the systemic mean arterial pressure to 60 mmHg for 120 min by blood withdrawal. Central opiate receptor blockade was induced by 10 micrograms/kg intracerebroventricularly (i.c.v.) injected naloxone at the 60th min of the bleeding period. Cortical blood flow showed no improvement after i.c.v. naloxone administration. Medullary blood flow, however, increased significantly and approached the pre-bleeding control flow values following central opiate receptor blockade. The results indicate involvement of endogenous opioid mechanisms in the regulation of rCBF during hemorrhage and may provide an explanation for the previously described beneficial effects of naloxone in hemorrhagic shock.

  7. NMDA receptor blockade attenuates locomotion elicited by intrastriatal dopamine D1-receptor stimulation.

    PubMed

    Kreipke, Christian W; Walker, Paul D

    2004-07-01

    Previous behavioral studies suggest that the striatum mediates a hyperactive response to systemic NMDA receptor antagonism in combination with systemic D1 receptor stimulation. However, many experiments conducted at the cellular level suggest that inhibition of NMDA receptors should block D1 receptor-mediated locomotor activity. Therefore, we investigated the consequences of NMDA receptor blockade on the ability of striatal D1 receptors to elicit locomotor activity using systemic and intrastriatal injections of the NMDA antagonist MK-801 combined with intrastriatal injections of the D1 full agonist SKF 82958. Following drug treatment locomotor activity was measured via computerized activity monitors designed to quantify multiple parameters of rodent open-field behavior. Both systemic (0.1 mg/kg) and intrastriatal (1.0 microg) MK-801 pretreatments completely blocked locomotor and stereotypic activity elicited by 10 microg of SKF 82958 directly infused into the striatum. Further, increased activity triggered by intrastriatal SKF 82958 was attenuated by a posttreatment with intrastriatal infusion of 1 microg MK-801. These data suggest that D1-stimulated locomotor behaviors controlled by the striatum require functional NMDA channels.

  8. Angiogenesis and radiation response modulation after vascular endothelial growth factor receptor-2 (VEGFR2) blockade

    SciTech Connect

    Li Jing; Huang Shyhmin; Armstrong, Eric A.; Fowler, John F.; Harari, Paul M. . E-mail: harari@humonc.wisc.edu

    2005-08-01

    The formation of new blood vessels (angiogenesis) represents a critical factor in the malignant growth of solid tumors and metastases. Vascular endothelial cell growth factor (VEGF) and its receptor VEGFR2 represent central molecular targets for antiangiogenic intervention, because of their integral involvement in endothelial cell proliferation and migration. In the current study, we investigated in vitro and in vivo effects of receptor blockade on various aspects of the angiogenic process using monoclonal antibodies against VEGFR2 (cp1C11, which is human specific, and DC101, which is mouse specific). Molecular blockade of VEGFR2 inhibited several critical steps involved in angiogenesis. VEGFR2 blockade in endothelial cells attenuated cellular proliferation, reduced cellular migration, and disrupted cellular differentiation and resultant formation of capillary-like networks. Further, VEGFR2 blockade significantly reduced the growth response of human squamous cell carcinoma xenografts in athymic mice. The growth-inhibitory effect of VEGFR2 blockade in tumor xenografts seems to reflect antiangiogenic influence as demonstrated by vascular growth inhibition in an in vivo angiogenesis assay incorporating tumor-bearing Matrigel plugs. Further, administration of VEGFR2-blocking antibodies in endothelial cell cultures, and in mouse xenograft models, increased their response to ionizing radiation, indicating an interactive cytotoxic effect of VEGFR2 blockade with radiation. These data suggest that molecular inhibition of VEGFR2 alone, and in combination with radiation, can enhance tumor response through molecular targeting of tumor vasculature.

  9. CB(1) blockade-induced weight loss over 48 weeks decreases liver fat in proportion to weight loss in humans.

    PubMed

    Bergholm, R; Sevastianova, K; Santos, A; Kotronen, A; Urjansson, M; Hakkarainen, A; Lundbom, J; Tiikkainen, M; Rissanen, A; Lundbom, N; Yki-Järvinen, H

    2013-05-01

    Studies in mice have suggested that endocannabinoid blockade using the cannabinoid receptor type 1 (CB1) blocker rimonabant prevents obesity-induced hepatic steatosis. To determine effects of rimonabant on liver fat in humans, we measured liver fat content by proton magnetic resonance spectroscopy in 37 subjects who used either a CB1 blocker rimonabant or placebo in a double-blind, randomized manner. This was retrospectively compared with a historical hypocaloric diet weight loss group (n=23). Weight loss averaged 8.5±1.4 kg in the rimonabant, 1.7±1.0 kg in the placebo and 7.5±0.2 kg in the hypocaloric diet group (P<0.001, rimonabant vs placebo; NS, rimonabant vs hypocaloric diet). Liver fat decreased more in the rimonabant (5.9% (2.5-14.6%) vs 1.8% (0.9-3.5%), before vs after) than in the placebo group (6.8% (2.2-15.7%) vs 4.9% (1.6-7.8%), before vs after, P<0.05). The percentage change in body weight correlated closely with the percentage loss of liver fat (r=0.70, P>0.0001). The decreases in liver fat were comparable between the rimonabant and the young historical hypocaloric diet groups. We conclude that, unlike in mice, in humans rimonabant decreases liver fat in proportion to weight loss.

  10. Beta adrenergic receptor blockade of feline myocardium. Cardiac mechanics, energetics, and beta adrenoceptor regulation.

    PubMed Central

    Cooper, G; Kent, R L; McGonigle, P; Watanabe, A M

    1986-01-01

    Myocardial oxygen consumption is regulated by interrelated mechanical and inotropic conditions; there is a parallel increase in the aerobic metabolism and inotropic state during beta-adrenergic stimulation under fixed mechanical conditions. In contrast, there is some evidence that beta-blockade may reduce oxygen consumption through effects independent of its influence on mechanical conditions and contractile state, and that prolonged beta-blockade may sensitize the myocardium to beta-adrenergic stimulation. To clarify these two points, the present study examined the relationship of myocardial energetics to mechanics and inotropism during acute beta-blockade and after the withdrawal of long-term beta-blockade, whereupon the basis for any effect observed was sought by characterizing the number, affinity, and affinity states of the beta-receptors as well as the coupling of activated beta-receptors to cyclic AMP generation. Studies of right ventricular papillary muscles from control and chronically beta-blocked cats demonstrated contractile and energetic properties as well as dose-response behavior and inotropic specificity suggestive of an increase in myocardial sensitivity to beta-adrenoceptor stimulation in the latter group. Assays of cardiac beta-adrenoceptors from further groups of control and pretreated cats, both in cardiac tissue and in isolated cardiac muscle cells, failed to define a difference between the two groups either in terms of receptor number and affinity or in terms of the proportion of receptors in the high-affinity state. However, coupling of the activated beta-adrenoceptors to cyclic AMP generation was enhanced in cardiac muscle cells from chronically beta-blocked cats. These data demonstrate that beta-adrenoceptor blockade (a) produces parallel effects on inotropic state and oxygen consumption without an independent effect on either and (b) increases myocardial sensitivity to beta-adrenergic stimulation after beta-blockade withdrawal, not by "up

  11. Histamine H3 receptor blockade improves cardiac function in canine anaphylaxis.

    PubMed

    Chrusch, C; Sharma, S; Unruh, H; Bautista, E; Duke, K; Becker, A; Kepron, W; Mink, S N

    1999-10-01

    In anaphylactic shock (AS), the relative effects of the autacoids including histamine, prostaglandins, and leukotrienes on causing cardiovascular collapse and the extent to which receptor blocking agents and pathway inhibitors may prevent this collapse are not clear. In a ragweed model of anaphylaxis, we examined whether pretreatment with H1, H2, H3 receptor blockers, and cyclooxygenase and leukotriene pathway inhibitors was useful in preventing the depression in left ventricular (LV) contractility known to occur in this model. The dose of allergen was varied to produce similar degrees of shock between treatments. The animals were studied under pentobarbital anesthesia in which the treatment studies were approximately 3 wk apart. LV volumes were measured by sonomicrometric techniques. During challenge, mean arterial blood pressure (Pa), cardiac output (Q), and LV end-diastolic pressure (LVEDP) decreased approximately 50% compared with preshock values in all treatments. Histamine H3 receptor blockade was associated with higher heart rates (HR) and higher stroke work (SW) (p < 0.05) as compared with the other treatment studies. We conclude that histamine H3 activation by inhibiting adrenergic neural norepinephrine release contributes to cardiovascular collapse in AS.

  12. [Pulmonary hemodynamics following experimental myocardial ischemia after the blockade of adrenergic receptors].

    PubMed

    Evlakhov, V I; Poiasov, I Z

    2015-01-01

    In acute experiments in anesthetized rabbits the changes of the pulmonary hemodynamics following 60 s myocardial ischemia in the region of the descendent left coronary artery were studied in control animals and after the blockade of α-adrenoreceptors by phentolamine or β-adrenoreceptors by propranolol. Following myocardial ischemia in control animals the pulmonary artery pressure and flow decreased, the pulmonary vascular resistance did not change, the left atrial pressure elevated; the cardiac output decreased more than pulmonary artery flow. Following myocardial ischemia after the blockade of β-adrenoreceptors the pulmonary artery pressure decreased more than in control animals, the pulmonary artery flow was decreased in the same level as in the last case. The pulmonary vascular resistance was diminished, the left atrial pressure increased; the pulmonary artery flow and cardiac output decreased in the same level. Following myocardial ischemia after the blockade of β-adrenoreceptors the pulmonary artery pressure and pulmonary vascular resistance decreased more than after the blockade of α-adrenoreceptors, the left atrial pressure did not change. In both cases the pulmonary artery flow decreased in the same level and its changes were correlated with venous return shifts. The differences of the pulmonary artery changes following myocardial ischemia after the blockade of α- and β-adrenoreceptors are caused not only the different pulmonary vascular resistance changes, but also the left atrial pressure.

  13. Normotensive sodium loading in normal man: regulation of renin secretion during beta-receptor blockade.

    PubMed

    Mølstrøm, Simon; Larsen, Nils H; Simonsen, Jane A; Washington, Remon; Bie, Peter

    2009-02-01

    Saline administration may change renin-angiotensin-aldosterone system (RAAS) activity and sodium excretion at constant mean arterial pressure (MAP). We hypothesized that such responses are elicited mainly by renal sympathetic nerve activity by beta1-receptors (beta1-RSNA), and tested the hypothesis by studying RAAS and renal excretion during slow saline loading at constant plasma sodium concentration (Na+ loading; 12 micromol Na+.kg(-1).min(-1) for 4 h). Normal subjects were studied on low-sodium intake with and without beta1-adrenergic blockade by metoprolol. Metoprolol per se reduced RAAS activity as expected. Na+ loading decreased plasma renin concentration (PRC) by one-third, plasma ANG II by one-half, and plasma aldosterone by two-thirds (all P < 0.05); surprisingly, these changes were found without, as well as during, acute metoprolol administration. Concomitantly, sodium excretion increased indistinguishably with and without metoprolol (16 +/- 2 to 71 +/- 14 micromol/min; 13 +/- 2 to 55 +/- 13 micromol/min, respectively). Na+ loading did not increase plasma atrial natriuretic peptide, glomerular filtration rate (GFR by 51Cr-EDTA), MAP, or cardiac output (CO by impedance cardiography), but increased central venous pressure (CVP) by approximately 2.0 mmHg (P < 0.05). During Na+ loading, sodium excretion increased with CVP at an average slope of 7 micromol.min(-1).mmHg(-1). Concomitantly, plasma vasopressin decreased by 30-40% (P < 0.05). In conclusion, beta1-adrenoceptor blockade affects neither the acute saline-mediated deactivation of RAAS nor the associated natriuretic response, and the RAAS response to modest saline loading seems independent of changes in MAP, CO, GFR, beta1-mediated effects of norepinephrine, and ANP. Unexpectedly, the results do not allow assessment of the relative importance of RAAS-dependent and -independent regulation of renal sodium excretion. The results are compatible with the notion that at constant arterial pressure, a volume

  14. Adenosine receptor blockade reduces splanchnic hyperemia in cirrhotic rats.

    PubMed

    Lee, S S; Chilton, E L; Pak, J M

    1992-06-01

    To explore a possible role for adenosine in the pathogenesis of the splanchnic hyperemia of cirrhosis, we administered 8-phenyltheophylline, a specific adenosine receptor antagonist, to rats with biliary cirrhosis caused by bile duct ligation and to control sham-operated rats. Micro-Doppler flow studies showed that a 10-mumol/kg dose of 8-phenyltheophylline completely abolished the superior mesenteric hyperemic response to infusions of exogenous adenosine in both cirrhotic and control rats. Analysis of regional blood flows by radioactive microspheres demonstrated that this dose of 8-phenyltheophylline in cirrhotic rats significantly increased portal tributary vascular resistance by 60% and decreased portal tributary blood flow by 26%. This decrease was entirely the result of a 42% reduction in the intestinal blood flow. 8-phenyltheophylline did not affect cardiac output, arterial pressure or any other extrasplanchnic hemodynamic variables in cirrhotic rats. No detectable effect of 8-phenyltheophylline was seen in sham-operated rats. These results suggest that adenosine may be involved in the genesis of splanchnic hyperemia in cirrhotic rats.

  15. Hepatic structural enhancement and insulin resistance amelioration due to AT1 receptor blockade.

    PubMed

    Souza-Mello, Vanessa

    2017-01-18

    Over the last decade, the role of renin-angiotensin system (RAS) on the development of obesity and its comorbidities has been extensively addressed. Both circulating and local RAS components are up-regulated in obesity and involved in non-alcoholic fatty liver disease onset. Pharmacological manipulations of RAS are viable strategies to tackle metabolic impairments caused by the excessive body fat mass. Renin inhibitors rescue insulin resistance, but do not have marked effects on hepatic steatosis. However, angiotensin-converting enzyme inhibitors and angiotensin receptor blockers (ARB) yield beneficial hepatic remodeling. ARBs elicit body mass loss and normalize insulin levels, tackling insulin resistance. Also, this drug class increases adiponectin levels, besides countering interleukin-6, tumoral necrosis factor-alpha, and transforming growth factor-beta 1. The latter is essential to prevent from liver fibrosis. When conjugated with peroxisome proliferator-activated receptor (PPAR)-alpha activation, ARB fully rescues fatty liver. These effects might be orchestrated by an indirect up-regulation of MAS receptor due to angiotensin II receptor type 1 (AT1R) blockade. These associations of ARB with PPAR activation and ACE2-angiotensin (ANG) (1-7)-MAS receptor axis deserve a better understanding. This editorial provides a brief overview of the current knowledge regarding AT1R blockade effects on sensitivity to insulin and hepatic structural alterations as well as the intersections of AT1R blockade with peroxisome proliferator-activated receptor activation and ACE2-ANG (1-7) - MAS receptor axis.

  16. Hepatic structural enhancement and insulin resistance amelioration due to AT1 receptor blockade

    PubMed Central

    Souza-Mello, Vanessa

    2017-01-01

    Over the last decade, the role of renin-angiotensin system (RAS) on the development of obesity and its comorbidities has been extensively addressed. Both circulating and local RAS components are up-regulated in obesity and involved in non-alcoholic fatty liver disease onset. Pharmacological manipulations of RAS are viable strategies to tackle metabolic impairments caused by the excessive body fat mass. Renin inhibitors rescue insulin resistance, but do not have marked effects on hepatic steatosis. However, angiotensin-converting enzyme inhibitors and angiotensin receptor blockers (ARB) yield beneficial hepatic remodeling. ARBs elicit body mass loss and normalize insulin levels, tackling insulin resistance. Also, this drug class increases adiponectin levels, besides countering interleukin-6, tumoral necrosis factor-alpha, and transforming growth factor-beta 1. The latter is essential to prevent from liver fibrosis. When conjugated with peroxisome proliferator-activated receptor (PPAR)-alpha activation, ARB fully rescues fatty liver. These effects might be orchestrated by an indirect up-regulation of MAS receptor due to angiotensin II receptor type 1 (AT1R) blockade. These associations of ARB with PPAR activation and ACE2-angiotensin (ANG) (1-7)-MAS receptor axis deserve a better understanding. This editorial provides a brief overview of the current knowledge regarding AT1R blockade effects on sensitivity to insulin and hepatic structural alterations as well as the intersections of AT1R blockade with peroxisome proliferator-activated receptor activation and ACE2-ANG (1-7) - MAS receptor axis. PMID:28144388

  17. Effects of combined endothelin A receptor and renin-angiotensin system blockade on the course of end-organ damage in 5/6 nephrectomized Ren-2 hypertensive rats.

    PubMed

    Vaněčková, Ivana; Kujal, Petr; Husková, Zuzana; Vaňourková, Zdeňka; Vernerová, Zdenka; Certíková Chábová, Věra; Skaroupková, Petra; Kramer, Herbert J; Tesař, Vladimír; Červenka, Luděk

    2012-01-01

    Our previous studies in rats with ablation nephrectomy have shown similar cardiorenal protective effects of renin-angiotensin system (RAS)-dependent treatment (combination of angiotensin-converting enzyme inhibitor and angiotensin II receptor blocker) and RAS-independent treatment (combination of α- and β-adrenoreceptor antagonist and diuretics). Moreover, selective blockade of endothelin (ET) receptor type A (ET(A)) improved survival rate and attenuated hypertension and organ damage in Ren-2 transgenic rats. Therefore, we were interested in whether ET(A) receptor blockade could have additive effects to the classical blockade of the RAS. Transgenic rats underwent 5/6 renal ablation at the age of 2 months and were treated for 20 weeks with RAS blockers alone (angiotensin II receptor blocker - losartan, and angiotensin-converting enzyme inhibitor - trandolapril), ET(A) receptor blocker alone (atrasentan) or with the combination of RAS and ET(A) receptor blockade. RAS blockade normalized blood pressure and improved survival. It decreased cardiac hypertrophy and proteinuria as well as tissue angiotensin II and ET-1 levels. In contrast, ET(A) receptor blockade only partially improved survival rate, reduced blood pressure, attenuated the development of cardiac hypertrophy and transiently reduced proteinuria. However, no additive cardio- and renoprotective effects of ET(A) and RAS blockade were noted at the end of the study. Copyright © 2012 S. Karger AG, Basel.

  18. Pharmacologic blockade of FAK autophosphorylation decreases human glioblastoma tumor growth and synergizes with temozolomide.

    PubMed

    Golubovskaya, Vita M; Huang, Grace; Ho, Baotran; Yemma, Michael; Morrison, Carl D; Lee, Jisook; Eliceiri, Brian P; Cance, William G

    2013-02-01

    Malignant gliomas are characterized by aggressive tumor growth with a mean survival of 15 to 18 months and frequently developed resistance to temozolomide. Therefore, strategies that sensitize glioma cells to temozolomide have a high translational impact. We have studied focal adhesion kinase (FAK), a tyrosine kinase and emerging therapeutic target that is known to be highly expressed and activated in glioma. In this report, we tested the FAK autophosphorylation inhibitor, Y15, in DBTRG and U87 glioblastoma cells. Y15 significantly decreased viability and clonogenicity in a dose-dependent manner, increased detachment in a dose- and time-dependent manner, caused apoptosis, and inhibited cell invasion in both cell lines. In addition, Y15 treatment decreased autophosphorylation of FAK in a dose-dependent manner and changed cell morphology by causing cell rounding in DBTRG and U87 cells. Administration of Y15 significantly decreased subcutaneous DBTRG tumor growth with decreased Y397-FAK autophosphorylation, activated caspase-3 and PARP. Y15 was administered in an orthotopic glioma model, leading to an increase in mouse survival. The combination of Y15 with temozolomide was more effective than either agent alone in decreasing viability and activating caspase-8 in DBTRG and U87 cells in vitro. In addition, the combination of Y15 and temozolomide synergistically blocked U87 brain tumor growth in vivo. Thus, pharmacologic blockade of FAK autophosphorylation with the oral administration of a small-molecule inhibitor Y15 has a potential to be an effective therapy approach for glioblastoma either alone or in combination with chemotherapy agents such as temozolomide.

  19. Effects of Calorie Restriction and IGF-1 Receptor Blockade on the Progression of 22Rv1 Prostate Cancer Xenografts

    PubMed Central

    Galet, Colette; Gray, Ashley; Said, Jonathan W.; Castor, Brandon; Wan, Junxiang; Beltran, Pedro J.; Calzone, Franck J.; Elashoff, David; Cohen, Pinchas; Aronson, William J.

    2013-01-01

    Calorie restriction (CR) inhibits prostate cancer progression, partially through modulation of the IGF axis. IGF-1 receptor (IGF-1R) blockade reduces prostate cancer xenograft growth. We hypothesized that combining calorie restriction with IGF-1R blockade would have an additive effect on prostate cancer growth. Severe combined immunodeficient mice were subcutaneously injected with 22Rv1 cells and randomized to: (1) Ad libitum feeding/intraperitoneal saline (Ad-lib); (2) Ad-lib/20 mg/kg twice weekly, intraperitoneal ganitumab [anti-IGF-1R antibody (Ad-lib/Ab)]; (3) 40% calorie restriction/intraperitoneal saline (CR); (4) CR/ intraperitoneal ganitumab, (CR/Ab). CR and ganitumab treatment were initiated one week after tumor injection. Euthanasia occurred 19 days post treatment. Results showed that CR alone decreased final tumor weight, plasma insulin and IGF-1 levels, and increased apoptosis. Ganitumab therapy alone reduced tumor growth but had no effect on final tumor weight. The combination therapy (CR/Ab) further decreased final tumor weight and proliferation, increased apoptosis in comparison to the Ad-lib group, and lowered plasma insulin levels relative to the Ad-lib and Ad-lib/Ab groups. Tumor AKT activation directly correlated with plasma IGF-1 levels. In conclusion, whereas ganitumab therapy modestly affected 22Rv1 tumor growth, combining IGF-1R blockade with calorie restriction resulted in a significant decrease in final tumor weight and improved metabolic profile. PMID:23823800

  20. Effects of calorie restriction and IGF-1 receptor blockade on the progression of 22Rv1 prostate cancer xenografts.

    PubMed

    Galet, Colette; Gray, Ashley; Said, Jonathan W; Castor, Brandon; Wan, Junxiang; Beltran, Pedro J; Calzone, Franck J; Elashoff, David; Cohen, Pinchas; Aronson, William J

    2013-07-03

    Calorie restriction (CR) inhibits prostate cancer progression, partially through modulation of the IGF axis. IGF-1 receptor (IGF-1R) blockade reduces prostate cancer xenograft growth. We hypothesized that combining calorie restriction with IGF-1R blockade would have an additive effect on prostate cancer growth. Severe combined immunodeficient mice were subcutaneously injected with 22Rv1 cells and randomized to: (1) Ad libitum feeding/intraperitoneal saline (Ad-lib); (2) Ad-lib/20 mg/kg twice weekly, intraperitoneal ganitumab [anti-IGF-1R antibody (Ad-lib/Ab)]; (3) 40% calorie restriction/intraperitoneal saline (CR); (4) CR/ intraperitoneal ganitumab, (CR/Ab). CR and ganitumab treatment were initiated one week after tumor injection. Euthanasia occurred 19 days post treatment. Results showed that CR alone decreased final tumor weight, plasma insulin and IGF-1 levels, and increased apoptosis. Ganitumab therapy alone reduced tumor growth but had no effect on final tumor weight. The combination therapy (CR/Ab) further decreased final tumor weight and proliferation, increased apoptosis in comparison to the Ad-lib group, and lowered plasma insulin levels relative to the Ad-lib and Ad-lib/Ab groups. Tumor AKT activation directly correlated with plasma IGF-1 levels. In conclusion, whereas ganitumab therapy modestly affected 22Rv1 tumor growth, combining IGF-1R blockade with calorie restriction resulted in a significant decrease in final tumor weight and improved metabolic profile.

  1. BLOCKADE OF BRAIN ANGIOTENSIN II AT1 RECEPTORS AMELIORATES STRESS, ANXIETY, BRAIN INFLAMMATION AND ISCHEMIA: THERAPEUTIC IMPLICATIONS

    PubMed Central

    SAAVEDRA, Juan M.; SÁNCHEZ-LEMUS, Enrique; BENICKY, Julius

    2010-01-01

    SUMMARY Poor adaptation to stress, alterations in cerebrovascular function and excessive brain inflammation play critical roles in the pathophysiology of many psychiatric and neurological disorders such as major depression, schizophrenia, post traumatic stress disorder, Parkinson's and Alzheimer's diseases and traumatic brain injury. Treatment for these highly prevalent and devastating conditions is at present very limited and many times inefficient, and the search for novel therapeutic options is of major importance. Recently, attention has been focused on the role of a brain regulatory peptide, Angiotensin II, and in the translational value of the blockade of its physiological AT1 receptors. In addition to its well-known cardiovascular effects, Angiotensin II, through AT1 receptor stimulation, is a pleiotropic brain modulatory factor involved in the control of the reaction to stress, in the regulation of cerebrovascular flow and the response to inflammation. Excessive brain AT1 receptor activity is associated with exaggerated sympathetic and hormonal response to stress, vulnerability to cerebrovascular ischemia and brain inflammation, processes leading to neuronal injury. In animal models, inhibition of brain AT1 receptor activity with systemically administered Angiotensin II receptor blockers is neuroprotective; it reduces exaggerated stress responses and anxiety, prevents stress-induced gastric ulcerations, decreases vulnerability to ischemia and stroke, reverses chronic cerebrovascular inflammation, and reduces acute inflammatory responses produced by bacterial endotoxin. These effects protect neurons from injury and contribute to increase the lifespan. Angiotensin II receptor blockers are compounds with a good margin of safety widely used in the treatment of hypertension and their anti-inflammatory and vascular protective effects contribute to reduce renal and cardiovascular failure. Inhibition of brain AT1 receptors in humans is also neuroprotective

  2. D2 receptor blockade by risperidone correlates with attention deficits in late-life schizophrenia.

    PubMed

    Uchida, Hiroyuki; Rajji, Tarek K; Mulsant, Benoit H; Kapur, Shitij; Pollock, Bruce G; Graff-Guerrero, Ariel; Menon, Mahesh; Mamo, David C

    2009-12-01

    The negative impact of antipsychotic drugs on attention is expected to be greater in late-life schizophrenia because of the age-related changes in the dopamine receptor reserve. The objective of this study was to examine the relationship between dopamine D2 receptor blockade by risperidone and the cognitive function in late-life schizophrenia. Subjects with schizophrenia or schizoaffective disorder aged 50 or older who were receiving risperidone completed a [C]raclopride positron emission tomography scan to measure D2-binding potential in the striatum. The D2 receptor blockade by risperidone was calculated using age-corrected measures from healthy individuals and region of interest analysis of dynamic positron emission tomography data coregistered to the subjects' magnetic resonance imaging scans. Cognitive function was assessed using a battery of neuropsychological tests that included the Dementia Rating Scale-2 (DRS). Eleven subjects (mean +/- SD age, 64 +/- 8 years) participated in this study. The mean +/- SD D2 receptor blockade was 69% +/- 14% (range, 34%-80%). The age-corrected score on the attention subscale in the DRS was negatively correlated with the D2 receptor blockade. The DRS attention subscale score was lower in the subjects who experienced 74.9% or higher D2 blockade (median value, corresponding to a daily risperidone dose of >3.0 mg) than in those who did not. Although a causal attribution cannot be made in light of the cross-sectional nature of this study, the results suggest the critical importance of identifying the lowest effective dose of antipsychotic drugs in older patients with schizophrenia.

  3. Blockade of Urotensin II Receptor Prevents Vascular Dysfunction

    PubMed Central

    Kim, Young-Ae; Lee, Dong Gil; Yi, Kyu Yang; Lee, Byung Ho; Jung, Yi-Sook

    2016-01-01

    Urotensin II (UII) is a potent vasoactive peptide and mitogenic agent to induce proliferation of various cells including vascular smooth muscle cells (VSMCs). In this study, we examined the effects of a novel UII receptor (UT) antagonist, KR-36676, on vasoconstriction of aorta and proliferation of aortic SMCs. In rat aorta, UII-induced vasoconstriction was significantly inhibited by KR-36676 in a concentration-dependent manner. In primary human aortic SMCs (hAoSMCs), UII-induced cell proliferation was significantly inhibited by KR-36676 in a concentration-dependent manner. In addition, KR-36676 decreased UII-induced phosphorylation of ERK, and UII-induced cell proliferation was also significantly inhibited by a known ERK inhibitor U0126. In mouse carotid ligation model, intimal thickening of carotid artery was dramatically suppressed by oral treatment with KR-36676 (30 mg/ kg/day) for 4 weeks compared to vehicle-treated group. From these results, it is indicated that KR-36676 suppress UII-induced proliferation of VSMCs at least partially through inhibition of ERK activation, and that it also attenuates UII-induced vasoconstriction and vascular neointima formation. Our study suggest that KR-36676 may be an attractive candidate for the pharmacological management of vascular dysfunction. PMID:27582556

  4. ETA receptor blockade with atrasentan prevents hypertension with the multitargeted tyrosine kinase inhibitor ABT-869 in telemetry-instrumented rats.

    PubMed

    Banfor, Patricia N; Franklin, Pamela A; Segreti, Jason A; Widomski, Deborah L; Davidsen, Steven K; Albert, Daniel H; Cox, Bryan F; Fryer, Ryan M; Gintant, Gary A

    2009-02-01

    ABT-869 is a novel multitargeted inhibitor of vascular endothelial growth factor and platelet-derived growth factor receptor tyrosine kinases (RTKs) with potent antiangiogenic properties that slow tumor progression. Vascular endothelial growth factor receptor blockade has been shown to produce hypertension. Atrasentan is a potent and selective endothelin (ETA) receptor antagonist that lowers blood pressure and affects tumor growth. To assess the utility of ETA receptor blockade in controlling hypertension with RTK inhibition, we evaluated the ability of atrasentan to block hypertension with ABT-869 in conscious, telemetry-instrumented rats. Changes in mean arterial pressure (MAP) and heart rate (HR) were evaluated using mean values and the area under the curve (AUC). Atrasentan (0.5, 1.5, and 5.0 mg kg(-1) d(-1) for 5 days) elicited dose-dependent decreases in MAP-AUC (-16.7 +/- 1.3, -20.94 +/- 3.68, and -30.12 +/- 3.57 mm Hg x day, respectively) compared with vehicle. ABT-869 (1, 3, 10, 30 mg kg(-1) d(-1) for 5 days) increased MAP compared with vehicle (MAP-AUC values of -5.52 +/- 3.75, 12.7 +/- 8.4, 37.5 +/- 4.4, and 63.8 +/- 3.3 mm Hg x day, respectively). Pretreatment with atrasentan (5 mg/kg for 5 days) prevented and abolished the hypertensive effects of ABT-869. Thus, ETA receptor blockade effectively alleviated hypertension with RTK inhibition and may serve a dual therapeutic role by preventing hypertension and slowing tumor progression.

  5. Blockade of glucocorticoid receptors improves cutaneous wound healing in stressed mice.

    PubMed

    de Almeida, Taís Fontoura; de Castro Pires, Taiza; Monte-Alto-Costa, Andréa

    2016-02-01

    Stress is an important condition of modern life. The successful wound healing requires the execution of three major overlapping phases: inflammation, proliferation, and remodeling, and stress can disturb this process. Chronic stress impairs wound healing through the activation of the hypothalamic-pituitary-adrenal axis, and the glucocorticoids (GCs) hormones have been shown to delay wound closure. Therefore, the aim of this study was to investigate the effects of a GC receptor antagonist (RU486) treatment on cutaneous healing in chronically stressed mice. Male mice were submitted to rotational stress, whereas control animals were not subjected to stress. Stressed and control animals were treated with RU486. A full-thickness excisional lesion was generated, and seven days later, lesions were recovered. The RU486 treatment improves wound healing since contraction takes place earlier in RU486-treated in comparison to non-treated mice, and the RU486 treatment also improves the angiogenesis in Stress+RU486 mice when compared to stressed animals. The Stress+RU486 group showed a decrease in inflammatory cell infiltration and in hypoxia-inducible factor-1α and inducible nitric oxide synthase expression; meanwhile, there was an increase in myofibroblasts quantity. In conclusion, blockade of GC receptors with RU486 partially ameliorates stress-impaired wound healing, suggesting that stress inhibits healing through more than one functional pathway. © 2016 by the Society for Experimental Biology and Medicine.

  6. Blockade of glucocorticoid receptors improves cutaneous wound healing in stressed mice

    PubMed Central

    de Almeida, Taís Fontoura; de Castro Pires, Taiza

    2016-01-01

    Stress is an important condition of modern life. The successful wound healing requires the execution of three major overlapping phases: inflammation, proliferation, and remodeling, and stress can disturb this process. Chronic stress impairs wound healing through the activation of the hypothalamic–pituitary–adrenal axis, and the glucocorticoids (GCs) hormones have been shown to delay wound closure. Therefore, the aim of this study was to investigate the effects of a GC receptor antagonist (RU486) treatment on cutaneous healing in chronically stressed mice. Male mice were submitted to rotational stress, whereas control animals were not subjected to stress. Stressed and control animals were treated with RU486. A full-thickness excisional lesion was generated, and seven days later, lesions were recovered. The RU486 treatment improves wound healing since contraction takes place earlier in RU486-treated in comparison to non-treated mice, and the RU486 treatment also improves the angiogenesis in Stress+RU486 mice when compared to stressed animals. The Stress+RU486 group showed a decrease in inflammatory cell infiltration and in hypoxia-inducible factor-1α and inducible nitric oxide synthase expression; meanwhile, there was an increase in myofibroblasts quantity. In conclusion, blockade of GC receptors with RU486 partially ameliorates stress-impaired wound healing, suggesting that stress inhibits healing through more than one functional pathway. PMID:26515142

  7. An mRNA expression analysis of stimulation and blockade of 5-HT7 receptors during memory consolidation.

    PubMed

    Pérez-García, Georgina; Gonzalez-Espinosa, Claudia; Meneses, Alfredo

    2006-04-25

    Despite the compelling support for 5-hydroxytryptamine (5-HT) receptors participation in learning and memory in mammal species, the molecular basis had been largely absent from any discussion of its mechanistic underpinnings. Here, we report that reverse transcriptase-polymerase chain reaction (RT-PCR) analysis revealed that there was a higher level of expression of the investigated 5-HT receptor mRNAs in autoshaping-trained relative to untrained groups. Actually, pharmacological naïve untrained and autoshaping-trained rats showed significant differences, the latter groups expressing, in decreasing order, 5-HT1A < 5-HT6 < 5-HT4 < or = 5-HT7 receptors mRNA in prefrontal cortex and hippocampus. In order to determine more precisely mRNA expression and memory consolidation, we combined selective 5-HT7 receptors stimulation or blockade in the same animals, and brain areas individually analyzed. 5-HT7 receptors were strongly expressed in all the three brain areas of vehicle-trained rats relative to untrained group. The potential selective 5-HT7 receptor agonist AS 19 enhanced memory consolidation, attenuated mRNA receptors expression, and the facilitatory memory effect was reversed by SB-269970. Finally, pharmacological stimulation of 5-HT7 receptors reversed scopolamine- or dizocilpine-induced amnesia and receptor down-regulation.

  8. Hypocretin receptor 1 blockade preferentially reduces high effort responding for cocaine without promoting sleep

    PubMed Central

    Brodnik, Zachary D.; Bernstein, David L.; Prince, Courtney D.; España, Rodrigo A.

    2015-01-01

    Recent evidence suggests that blockade of the hypocretin receptor 1 may act as a useful pharmacotherapy for cocaine abuse. Here we investigated the extent to which various doses of a hypocretin receptor 1 antagonist, SB-334867, affect cocaine self-administration at varying doses of cocaine and across a range of effort requirements, and tested if these SB-334867 doses produce sedative effects. First, we trained animals to self-administer one of three doses of cocaine on a progressive ratio schedule, and then tested the effects of three doses of SB-334867. Responding for cocaine was then analyzed to segregate features of relatively high and low effort requirements across the progressive ratio session. In another set of experiments we tested the sleep-promoting effects of the same doses of SB-334867. Our data indicate that blockade of hypocretin receptor 1 preferentially reduces high effort responding for cocaine at levels that do not promote sedation. PMID:26049058

  9. Investigation of Prolactin Receptor Activation and Blockade Using Time-Resolved Fluorescence Resonance Energy Transfer

    PubMed Central

    Tallet, Estelle; Fernandez, Isabelle; Zhang, Chi; Salsac, Marion; Gregor, Nathalie; Ayoub, Mohammed Akli; Pin, Jean Philippe; Trinquet, Eric; Goffin, Vincent

    2011-01-01

    The prolactin receptor (PRLR) is emerging as a therapeutic target in oncology. Knowledge-based drug design led to the development of a pure PRLR antagonist (Del1-9-G129R-hPRL) that was recently shown to prevent PRL-induced mouse prostate tumorogenesis. In humans, the first gain-of-function mutation of the PRLR (PRLRI146L) was recently identified in breast tumor patients. At the molecular level, the actual mechanism of action of these two novel players in the PRL system remains elusive. In this study, we addressed whether constitutive PRLR activation (PRLRI146L) or PRLR blockade (antagonist) involved alteration of receptor oligomerization and/or of inter-chain distances compared to unstimulated and PRL-stimulated PRLR. Using a combination of various biochemical and spectroscopic approaches (co-IP, blue native electrophoresis, BRET1), we demonstrated that preformed PRLR homodimers are altered neither by PRL- or I146L-induced receptor triggering, nor by antagonist-mediated blockade. These findings were confirmed using a novel time-resolved fluorescence resonance energy transfer (TR-FRET) technology that allows monitoring distance changes between cell surface tagged receptors. This technology revealed that PRLR blockade or activation did not involve detectable distance changes between extracellular domains of receptor chains within the dimer. This study merges with our previous structural investigations suggesting that the mechanism of PRLR activation solely involves intermolecular contact adaptations leading to subtle intramolecular rearrangements. PMID:22649370

  10. Orexin-1 receptor blockade dysregulates REM sleep in the presence of orexin-2 receptor antagonism

    PubMed Central

    Dugovic, Christine; Shelton, Jonathan E.; Yun, Sujin; Bonaventure, Pascal; Shireman, Brock T.; Lovenberg, Timothy W.

    2014-01-01

    In accordance with the prominent role of orexins in the maintenance of wakefulness via activation of orexin-1 (OX1R) and orexin-2 (OX2R) receptors, various dual OX1/2R antagonists have been shown to promote sleep in animals and humans. While selective blockade of OX2R seems to be sufficient to initiate and prolong sleep, the beneficial effect of additional inhibition of OX1R remains controversial. The relative contribution of OX1R and OX2R to the sleep effects induced by a dual OX1/2R antagonist was further investigated in the rat, and specifically on rapid eye movement (REM) sleep since a deficiency of the orexin system is associated with narcolepsy/cataplexy based on clinical and pre-clinical data. As expected, the dual OX1/2R antagonist SB-649868 was effective in promoting non-REM (NREM) and REM sleep following oral dosing (10 and 30 mg/kg) at the onset of the dark phase. However, a disruption of REM sleep was evidenced by a more pronounced reduction in the onset of REM as compared to NREM sleep, a marked enhancement of the REM/total sleep ratio, and the occurrence of a few episodes of direct wake to REM sleep transitions (REM intrusion). When administered subcutaneously, the OX2R antagonist JNJ-10397049 (10 mg/kg) increased NREM duration whereas the OX1R antagonist GSK-1059865 (10 mg/kg) did not alter sleep. REM sleep was not affected either by OX2R or OX1R blockade alone, but administration of the OX1R antagonist in combination with the OX2R antagonist induced a significant reduction in REM sleep latency and an increase in REM sleep duration at the expense of the time spent in NREM sleep. These results indicate that additional blockade of OX1R to OX2R antagonism elicits a dysregulation of REM sleep by shifting the balance in favor of REM sleep at the expense of NREM sleep that may increase the risk of adverse events. Translation of this hypothesis remains to be tested in the clinic. PMID:24592208

  11. Orexin-1 receptor blockade dysregulates REM sleep in the presence of orexin-2 receptor antagonism.

    PubMed

    Dugovic, Christine; Shelton, Jonathan E; Yun, Sujin; Bonaventure, Pascal; Shireman, Brock T; Lovenberg, Timothy W

    2014-01-01

    In accordance with the prominent role of orexins in the maintenance of wakefulness via activation of orexin-1 (OX1R) and orexin-2 (OX2R) receptors, various dual OX1/2R antagonists have been shown to promote sleep in animals and humans. While selective blockade of OX2R seems to be sufficient to initiate and prolong sleep, the beneficial effect of additional inhibition of OX1R remains controversial. The relative contribution of OX1R and OX2R to the sleep effects induced by a dual OX1/2R antagonist was further investigated in the rat, and specifically on rapid eye movement (REM) sleep since a deficiency of the orexin system is associated with narcolepsy/cataplexy based on clinical and pre-clinical data. As expected, the dual OX1/2R antagonist SB-649868 was effective in promoting non-REM (NREM) and REM sleep following oral dosing (10 and 30 mg/kg) at the onset of the dark phase. However, a disruption of REM sleep was evidenced by a more pronounced reduction in the onset of REM as compared to NREM sleep, a marked enhancement of the REM/total sleep ratio, and the occurrence of a few episodes of direct wake to REM sleep transitions (REM intrusion). When administered subcutaneously, the OX2R antagonist JNJ-10397049 (10 mg/kg) increased NREM duration whereas the OX1R antagonist GSK-1059865 (10 mg/kg) did not alter sleep. REM sleep was not affected either by OX2R or OX1R blockade alone, but administration of the OX1R antagonist in combination with the OX2R antagonist induced a significant reduction in REM sleep latency and an increase in REM sleep duration at the expense of the time spent in NREM sleep. These results indicate that additional blockade of OX1R to OX2R antagonism elicits a dysregulation of REM sleep by shifting the balance in favor of REM sleep at the expense of NREM sleep that may increase the risk of adverse events. Translation of this hypothesis remains to be tested in the clinic.

  12. Blockade of P-Glycoprotein Decreased the Disposition of Phenformin and Increased Plasma Lactate Level

    PubMed Central

    Choi, Min-Koo; Song, Im-Sook

    2016-01-01

    This study aimed to investigate the in vivo relevance of P-glycoprotein (P-gp) in the pharmacokinetics and adverse effect of phenformin. To investigate the involvement of P-gp in the transport of phenformin, a bi-directional transport of phenformin was carried out in LLC-PK1 cells overexpressing P-gp, LLC-PK1-Pgp. Basal to apical transport of phenformin was 3.9-fold greater than apical to basal transport and became saturated with increasing phenformin concentration (2–75 μM) in LLC-PK1-Pgp, suggesting the involvement of P-gp in phenformin transport. Intrinsic clearance mediated by P-gp was 1.9 μL/min while passive diffusion clearance was 0.31 μL/min. Thus, P-gp contributed more to phenformin transport than passive diffusion. To investigate the contribution of P-gp on the pharmacokinetics and adverse effect of phenformin, the effects of verapamil, a P-gp inhibitor, on the pharmacokinetics of phenformin were also examined in rats. The plasma concentrations of phenformin were increased following oral administration of phenformin and intravenous verapamil infusion compared with those administerd phenformin alone. Pharmacokinetic parameters such as Cmax and AUC of phenformin increased and CL/F and Vss/F decreased as a consequence of verapamil treatment. These results suggested that P-gp blockade by verapamil may decrease the phenformin disposition and increase plasma phenformin concentrations. P-gp inhibition by verapamil treatment also increased plasma lactate concentration, which is a crucial adverse event of phenformin. In conclusion, P-gp may play an important role in phenformin transport process and, therefore, contribute to the modulation of pharmacokinetics of phenformin and onset of plasma lactate level. PMID:26797108

  13. Neuroprotection by adenosine A2A receptor blockade in experimental models of Parkinson's disease.

    PubMed

    Ikeda, Ken; Kurokawa, Masako; Aoyama, Shiro; Kuwana, Yoshihisa

    2002-01-01

    Adenosine A2A receptors are abundant in the caudate-putamen and involved in the motor control in several species. In MPTP-treated monkeys, A2A receptor-blockade with an antagonist alleviates parkinsonian symptoms without provoking dyskinesia, suggesting this receptor may offer a new target for the antisymptomatic therapy of Parkinson's disease. In the present study, a significant neuroprotective effect of A2A receptor antagonists is shown in experimental models of Parkinson's disease. Oral administration of A2A receptor antagonists protected against the loss of nigral dopaminergic neuronal cells induced by 6-hydroxydopamine in rats. A2A antagonists also prevented the functional loss of dopaminergic nerve terminals in the striatum and the ensuing gliosis caused by MPTP in mice. The neuroprotective property of A2A receptor antagonists may be exerted by altering the packaging of these neurotoxins into vesicles, thus reducing their effective intracellular concentration. We therefore conclude that the adenosine A2A receptor may provide a novel target for the long-term medication of Parkinson's disease, because blockade of this receptor exerts both acutely antisymptomatic and chronically neuroprotective activities.

  14. Dopamine D2-receptor blockade enhances decoding of prefrontal signals in humans.

    PubMed

    Kahnt, Thorsten; Weber, Susanna C; Haker, Helene; Robbins, Trevor W; Tobler, Philippe N

    2015-03-04

    The prefrontal cortex houses representations critical for ongoing and future behavior expressed in the form of patterns of neural activity. Dopamine has long been suggested to play a key role in the integrity of such representations, with D2-receptor activation rendering them flexible but weak. However, it is currently unknown whether and how D2-receptor activation affects prefrontal representations in humans. In the current study, we use dopamine receptor-specific pharmacology and multivoxel pattern-based functional magnetic resonance imaging to test the hypothesis that blocking D2-receptor activation enhances prefrontal representations. Human subjects performed a simple reward prediction task after double-blind and placebo controlled administration of the D2-receptor antagonist amisulpride. Using a whole-brain searchlight decoding approach we show that D2-receptor blockade enhances decoding of reward signals in the medial orbitofrontal cortex. Examination of activity patterns suggests that amisulpride increases the separation of activity patterns related to reward versus no reward. Moreover, consistent with the cortical distribution of D2 receptors, post hoc analyses showed enhanced decoding of motor signals in motor cortex, but not of visual signals in visual cortex. These results suggest that D2-receptor blockade enhances content-specific representations in frontal cortex, presumably by a dopamine-mediated increase in pattern separation. These findings are in line with a dual-state model of prefrontal dopamine, and provide new insights into the potential mechanism of action of dopaminergic drugs.

  15. Assessment of dopamine receptor blockade by neuroleptic drugs in the living human brain

    SciTech Connect

    Wong, D.F.; Wagner, H.N. Jr.; Coyle, J.; Snyder, S.; Dannals, R.; LaFrance, N.; Bice, A.; Pearlson, G.; Links, J.; Paulos, M.

    1985-05-01

    Positron emission tomography (PET) makes it possible to attempt to relate directly the antipsychotic effect of neuroleptic drugs and their blocking effect on dopamine receptors (D2) in vivo. The authors have examined the ability of haloperidol (HAL) and molindone (MOL) to block the binding of C-11 n-methylspiperone (NMSP) in 6 normal subjects. A dose of 0.05 mg/kg of HAL resulted in a 68% drop in the slope of the caudate/cerebellum (Ca/Cb) vs. time. This slope is related to the rate of specific binding of NMSP to the receptor. A dose response was seen with both drugs. With increasing doses of HAL from .05 to 0.082 mg/kg, CA/Cb vs. time slope fell from .235 to .156/min. (N=4), progressively. Similarly with increasing doses of MOL of .16-.44 mg/kg slopes decreased from .0335 to .0155/min. (N=4). Similar degrees of post injection Ca/Cb ratio were produced with quantities of MOL and HAL administered in the oral dose ratio of doses 3-5:1 times greater than HAL. This is also the dose ratio at which we found similar dopamine receptor blockade by PET in vivo. A question that arises is why the in vitro affinity of HAL for D2 is 30 times greater than that of MOL in the human brain. The results raise the possibility that MOL metabolites are not only active in blocking D2 but indeed may possibly be more potent than MOL itself. It also helps confirm the site of action of MOL and its in vivo metabolites.

  16. Fear memory in a neurodevelopmental model of schizophrenia based on the postnatal blockade of NMDA receptors.

    PubMed

    Latusz, Joachim; Radaszkiewicz, Aleksandra; Bator, Ewelina; Wędzony, Krzysztof; Maćkowiak, Marzena

    2017-02-01

    Epidemiological data have indicated that memory impairment is observed during adolescence in groups at high risk for schizophrenia and might precede the appearance of schizophrenia symptoms in adulthood. In the present study, we used a neurodevelopmental model of schizophrenia based on the postnatal blockade of N-methyl-d-aspartate (NMDA) receptors in rats to investigate fear memory in adolescence and adulthood. The rats were treated with increasing doses of CGP 37849 (CGP), a competitive antagonist of the NMDA receptor (1.25mg/kg on days 1, 3, 6, 9; 2.5mg/kg on days 12, 15, 18 and 5mg/kg on day 21). Fear memory was analysed in delay and trace fear conditioning. Sensorimotor gating deficit, which is another cognitive symptom of schizophrenia, was also determined in adolescent and adult CGP-treated rats. Postnatal CGP administration disrupted cue- and context-dependent fear memory in adolescent rats in both delay and trace conditioning. In contrast, CGP administration evoked impairment only in cue-dependent fear memory in rats exposed to trace but not delay fear conditioning. The postnatal blockade of NMDA receptors induced sensorimotor gating deficits in adult rats but not in adolescent rats. The postnatal blockade of NMDA receptors induced fear memory impairment in adolescent rats before the onset of neurobehavioral deficits associated with schizophrenia. Copyright © 2016. Published by Elsevier Urban & Partner Sp. z o.o.

  17. Hypotensive effect of angiotensin II after AT1-receptor blockade with losartan.

    PubMed

    Matys, T; Pawlak, R; Kucharewicz, I; Chabielska, E; Buczko, W

    2000-03-01

    Recent data suggest that hypotensive effect of losartan may not be attributed solely to AT1-receptor blockade, but also to excessive AT2 or other receptors stimulation by elevated angiotensin II and its derivative peptides. Therefore in the present study we examined the effect of angiotensin II on mean blood pressure after AT -receptor blockade with losartan. Male Wistar rats were anaesthetised and received injection of either losartan (30 mg/kg, 1 ml/kg, i.v.) or saline (the same volume and route) followed by bolus injection of angiotensin II (100, 300 or 1,000 ng/kg; 1 ml/kg, i.v.) or 1-hour infusion of angiotensin II (200 ng/kg/min; 2.5 ml/kg/h, i.v.). Control animals received saline instead. Angiotensin II, given either as the injection or the infusion, caused an evident increase in mean blood pressure (p ranged from 0.05 to 0.001 depending on the experimental group). Losartan caused a rapid drop in mean blood pressure and blunted the hypertensive effect of angiotensin II (p < 0.01). Moreover, in the losartan-pretreated animals the hypotensive phase was enhanced by the infusion, but not single injection of angiotensin II, which was most evident from the 30 th minute of observation (p < 0.05 vs control). In conclusion, hypotensive effect of losartan may be amplified by simultaneous increase in angiotensin II level, the situation observed during chronic AT1-receptor blockade.

  18. Normotensive sodium loading in conscious dogs: regulation of renin secretion during beta-receptor blockade.

    PubMed

    Bie, Peter; Mølstrøm, Simon; Wamberg, Søren

    2009-02-01

    Renin secretion is regulated in part by renal nerves operating through beta1-receptors of the renal juxtaglomerular cells. Slow sodium loading may decrease plasma renin concentration (PRC) and cause natriuresis at constant mean arterial blood pressure (MAP) and glomerular filtration rate (GFR). We hypothesized that in this setting, renin secretion and renin-dependent sodium excretion are controlled by via the renal nerves and therefore are eliminated or reduced by blocking the action of norepinephrine on the juxtaglomerular cells with the beta1-receptor antagonist metoprolol. This was tested in conscious dogs by infusion of NaCl (20 micromol.kg(-1).min(-1) for 180 min, NaLoad) during regular or low-sodium diet (0.03 mmol.kg(-1).day(-1), LowNa) with and without metoprolol (2 mg/kg plus 0.9 mg.kg(-1).h(-1)). Vasopressin V2 receptors were blocked by Otsuka compound OPC31260 to facilitate clearance measurements. Body fluid volume was maintained by servocontrolled fluid infusion. Metoprolol per se did not affect MAP, heart rate, or sodium excretion significantly, but reduced PRC and ANG II by 30-40%, increased plasma atrial natriuretic peptide (ANP), and tripled potassium excretion. LowNa per se increased PRC (+53%), ANG II (+93%), and aldosterone (+660%), and shifted the vasopressin function curve to the left. NaLoad elevated plasma [Na+] by 4.5% and vasopressin by threefold, but MAP and plasma ANP remained unchanged. NaLoad decreased PRC by approximately 30%, ANG II by approximately 40%, and aldosterone by approximately 60%, regardless of diet and metoprolol. The natriuretic response to NaLoad was augmented during metoprolol regardless of diet. In conclusion, PRC depended on dietary sodium and beta1-adrenergic control as expected; however, the acute sodium-driven decrease in PRC at constant MAP and GFR was unaffected by beta1-receptor blockade demonstrating that renin may be regulated without changes in MAP, GFR, or beta1-mediated effects of norepinephrine. Low

  19. Heterologous immunity triggered by a single, latent virus in Mus musculus: combined costimulation- and adhesion- blockade decrease rejection.

    PubMed

    Beus, Jonathan M; Hashmi, Salila S; Selvaraj, Saranya A; Duan, Danxia; Stempora, Linda L; Monday, Stephanie A; Cheeseman, Jennifer A; Hamby, Kelly M; Speck, Samuel H; Larsen, Christian P; Kirk, Allan D; Kean, Leslie S

    2013-01-01

    The mechanisms underlying latent-virus-mediated heterologous immunity, and subsequent transplant rejection, especially in the setting of T cell costimulation blockade, remain undetermined. To address this, we have utilized MHV68 to develop a rodent model of latent virus-induced heterologous alloimmunity. MHV68 infection was correlated with multimodal immune deviation, which included increased secretion of CXCL9 and CXCL10, and with the expansion of a CD8(dim) T cell population. CD8(dim) T cells exhibited decreased expression of multiple costimulation molecules and increased expression of two adhesion molecules, LFA-1 and VLA-4. In the setting of MHV68 latency, recipients demonstrated accelerated costimulation blockade-resistant rejection of skin allografts compared to non-infected animals (MST 13.5 d in infected animals vs 22 d in non-infected animals, p<.0001). In contrast, the duration of graft acceptance was equivalent between non-infected and infected animals when treated with combined anti-LFA-1/anti-VLA-4 adhesion blockade (MST 24 d for non-infected and 27 d for infected, p = n.s.). The combination of CTLA-4-Ig/anti-CD154-based costimulation blockade+anti-LFA-1/anti-VLA-4-based adhesion blockade led to prolonged graft acceptance in both non-infected and infected cohorts (MST>100 d for both, p<.0001 versus costimulation blockade for either). While in the non-infected cohort, either CTLA-4-Ig or anti-CD154 alone could effectively pair with adhesion blockade to prolong allograft acceptance, in infected animals, the prolonged acceptance of skin grafts could only be recapitulated when anti-LFA-1 and anti-VLA-4 antibodies were combined with anti-CD154 (without CTLA-4-Ig, MST>100 d). Graft acceptance was significantly impaired when CTLA-4-Ig alone (no anti-CD154) was combined with adhesion blockade (MST 41 d). These results suggest that in the setting of MHV68 infection, synergy occurs predominantly between adhesion pathways and CD154-based costimulation, and

  20. Early BAFF receptor blockade mitigates murine Sjögren's syndrome: Concomitant targeting of CXCL13 and the BAFF receptor prevents salivary hypofunction

    PubMed Central

    Klimatcheva, Ekaterina; Howell, Alan; Fereidouni, Farzad; Levenson, Richard; Rothstein, Thomas L.; Kramer, Jill M.

    2016-01-01

    Sjögren's Syndrome (SS) is a debilitating autoimmune disease. Patients with SS may develop xerostomia. This process is progressive, and there are no therapeutics that target disease etiology. We hypothesized BAFF receptor (BAFFR) blockade would mitigate SS disease development, and neutralization of CXCL13 and BAFF signaling would be more efficacious than BAFFR blockade alone. We treated NOD/ShiLtJ SS mice with soluble BAFF receptor (BAFFR-Fc) or anti-CXCL13/BAFFR-Fc in combination, prior to the development of clinical disease. Our results show treatment with BAFFR-Fc reduced peripheral B cells numbers and decreased sialadenitis. In addition, this treatment reduced total serum immunoglobulin as well as IgG and IgM specific anti-nuclear autoantibodies. NOD/ShiLtJ mice treated with BAFFR-Fc and anti-CXCL13 antibody were protected from salivary deficits. Results from this study suggest blockade of CXCL13 and BAFFR together may be an effective therapeutic strategy in preventing salivary hypofunction and reducing autoantibody titers and sialadenitis in patients with SS. PMID:26826598

  1. Early BAFF receptor blockade mitigates murine Sjögren's syndrome: Concomitant targeting of CXCL13 and the BAFF receptor prevents salivary hypofunction.

    PubMed

    Sharma, Arjun; Kiripolsky, Jeremy; Klimatcheva, Ekaterina; Howell, Alan; Fereidouni, Farzad; Levenson, Richard; Rothstein, Thomas L; Kramer, Jill M

    2016-03-01

    Sjögren's syndrome (SS) is a debilitating autoimmune disease. Patients with SS may develop xerostomia. This process is progressive, and there are no therapeutics that target disease etiology. We hypothesized BAFF receptor (BAFFR) blockade would mitigate SS disease development, and neutralization of CXCL13 and BAFF signaling would be more efficacious than BAFFR blockade alone. We treated NOD/ShiLtJ SS mice with soluble BAFF receptor (BAFFR-Fc) or anti-CXCL13/BAFFR-Fc in combination, prior to the development of clinical disease. Our results show treatment with BAFFR-Fc reduced peripheral B cell numbers and decreased sialadenitis. In addition, this treatment reduced total serum immunoglobulin as well as IgG and IgM specific anti-nuclear autoantibodies. NOD/ShiLtJ mice treated with BAFFR-Fc and anti-CXCL13 antibody were protected from salivary deficits. Results from this study suggest blockade of CXCL13 and BAFFR together may be an effective therapeutic strategy in preventing salivary hypofunction and reducing autoantibody titers and sialadenitis in patients with SS.

  2. Perirhinal Cortex Muscarinic Receptor Blockade Impairs Taste Recognition Memory Formation

    ERIC Educational Resources Information Center

    Gutierrez, Ranier; De la Cruz, Vanesa; Rodriguez-Ortiz, Carlos J.; Bermudez-Rattoni, Federico

    2004-01-01

    The relevance of perirhinal cortical cholinergic and glutamatergic neurotransmission for taste recognition memory and learned taste aversion was assessed by microinfusions of muscarinic (scopolamine), NMDA (AP-5), and AMPA (NBQX) receptor antagonists. Infusions of scopolamine, but not AP5 or NBQX, prevented the consolidation of taste recognition…

  3. Blockade of alpha 2-adrenergic receptors, but not blockade of gamma-aminobutyric acidA, serotonin, or opiate receptors, augments responsiveness of locus coeruleus neurons to excitatory stimulation.

    PubMed

    Simson, P E; Weiss, J M

    1989-07-01

    Previous studies in this laboratory indicated that alpha 2-adrenergic receptors in the locus coeruleus play a major role in regulating the responsiveness of neurons in the locus coeruleus to excitatory influences. The present study points to the possibility that alpha 2-receptors are unique among inhibitory receptors in the locus coeruleus in regulating responsiveness of these neurons independently of the spontaneous firing rate. In the first part of the study, blockade of alpha 2-receptors was shown to markedly augment responsiveness of neurons in the locus coeruleus to the excitatory stimulus of compression of the contralateral hind paw at doses of an alpha 2-blocker both above and well below those necessary to increase spontaneous activity of neurons in the locus coeruleus. In contrast, blockade of gamma-aminobutyric acid and serotonin receptors augmented spontaneous firing rates of neurons in the locus coeruleus but failed to augment responsiveness of these neurons to compression of the hindpaw. Blockade of opiate receptors failed to increase either spontaneous firing rates or the responsiveness of neurons of the locus coeruleus to paw compression; moreover, in animals given an opiate agonist over a number of days to produce tonic stimulation of opiate receptors, blockade of opiate receptors augmented spontaneous firing rates of neurons in the locus coeruleus but had no effect on responsiveness to paw compression. In that blockade of each type of inhibitory receptor tested increased the spontaneous firing rates of neurons in the locus coeruleus but only blockade of alpha 2-receptors increased the responsiveness of neurons in the locus coeruleus to stimulation, without affecting the spontaneous firing rate, alpha 2-receptors may be unique among inhibitory receptors in independently regulating the responsiveness of neurons in the locus coeruleus. One possibility discussed for why alpha 2-receptors regulate the responsiveness, independently of the spontaneous

  4. Early chronic blockade of NR2B subunits and transient activation of NMDA receptors modulate LTP in mouse auditory cortex.

    PubMed

    Mao, Yuting; Zang, Shaoyun; Zhang, Jiping; Sun, Xinde

    2006-02-16

    In the auditory cortex, the properties of NMDA receptors depend primarily on the ratio of NR2A and NR2B subunits. NR2B subunit expression is high at the beginning of critical period and lower in adulthood. Because NMDA receptors are crucial in triggering long-term potentiation (LTP) and long-term depression, developmental or experience-dependent modification of NMDAR subunit composition is likely to influence synaptic plasticity. To examine how NMDA subunit change during postnatal development affect the adult synaptic plasticity, we employed chronic ifenprodil blockade of NR2B subunits and analyzed evoked field potentials in adult C57BL/6 mice auditory cortex (AC). We found that chronic loss of NR2B activity led to a decline in LTP magnitude in the AC of adult mice. Adding NMDA to the artificial cerebrospinal fluid (ACSF) in blocked mice had the opposite effect, producing LTP magnitudes at or exceeding those found in treated or untreated animals. These results suggest that, even in adulthood when NR2B expression is downregulated, these receptor subunits play an important role in experience-dependent plasticity of mouse auditory cortex. Blockade from P60 did not result in any decrease of LTP amplitude, suggesting that chronic block in postnatal period may permanently affect cortical circuits so that they cannot produce significant LTP in adulthood.

  5. Evidence that the positive inotropic effects of the alkylxanthines are not due to adenosine receptor blockade.

    PubMed Central

    Collis, M. G.; Keddie, J. R.; Torr, S. R.

    1984-01-01

    We investigated the possibility that the positive inotropic effects of the alkylxanthines are due to adenosine receptor blockade. The potency of 8-phenyltheophylline, theophylline and enprofylline as adenosine antagonists was assessed in vitro, using the guinea-pig isolated atrium, and in vivo, using the anaesthetized dog. The order of potency of the alkylxanthines as antagonists of the negative inotropic response to 2-chloroadenosine in vitro, and of the hypotensive response to adenosine in vivo was 8-phenyltheophylline greater than theophylline greater than enprofylline. The order of potency of the alkylxanthines as positive inotropic and chronotropic agents in the anaesthetized dog was enprofylline greater than theophylline greater than 8-phenyltheophylline. The results of this study indicate that the inotropic effects of the alkylxanthines in the anaesthetized dog are not due to adenosine receptor blockade. PMID:6322898

  6. Opiate receptor blockade on human granulosa cells inhibits VEGF release.

    PubMed

    Lunger, Fabian; Vehmas, Anni P; Fürnrohr, Barbara G; Sopper, Sieghart; Wildt, Ludwig; Seeber, Beata

    2016-03-01

    The objectives of this study were to determine whether the main opioid receptor (OPRM1) is present on human granulosa cells and if exogenous opiates and their antagonists can influence granulosa cell vascular endothelial growth factor (VEGF) production via OPRM1. Granulosa cells were isolated from women undergoing oocyte retrieval for IVF. Complementary to the primary cells, experiments were conducted using COV434, a well-characterized human granulosa cell line. Identification and localization of opiate receptor subtypes was carried out using Western blot and flow cytometry. The effect of opiate antagonist on granulosa cell VEGF secretion was assessed by enzyme-linked immunosorbent assay. For the first time, the presence of OPRM1 on human granulosa cells is reported. Blocking of opiate signalling using naloxone, a specific OPRM1 antagonist, significantly reduced granulosa cell-derived VEGF levels in both COV434 and granulosa-luteal cells (P < 0.01). The presence of opiate receptors and opiate signalling in granulosa cells suggest a possible role in VEGF production. Targeting this signalling pathway could prove promising as a new clinical option in the prevention and treatment of ovarian hyperstimulation syndrome.

  7. Receptor for advanced glycation end product blockade enhances the chemotherapeutic effect of cisplatin in tongue squamous cell carcinoma by reducing autophagy and modulating the Wnt pathway.

    PubMed

    Zhao, Ziming; Wang, Hongyu; Zhang, Liao; Mei, Xifan; Hu, Jing; Huang, Keqiang

    2017-02-01

    Tongue squamous cell carcinoma (TSCC) is one of the most severe types of cancer with poor outcomes. Cisplatin is used widely to treat cancer cells, but many patients develop acquired drug resistance. The receptor for advanced glycation end products (RAGE) is expressed widely in TSCC and associated with drug-induced chemotherapy resistance. However, the effect of RAGE and cisplatin on Tca-8113 cells remains unknown. We assayed the combined use of RAGE blockade and cisplatin effect on Tca-8113 cells' viability by MTT and apoptosis rate of Tca-8113 cells on RAGE blockade+cisplatin treatment; cisplatin alone; or RAGE blockade alone by flow cytometry. We observed the expressions of autophagy-related proteins beclin1, LC3II, p62; Wnt signaling-related proteins β-catenin, GSK3β, WNT5A, ROR-2; and apoptosis-related protein cleaved caspase-3, bcl-2-associated X proteins using western blot. We determined WNT5A and beclin1 expression on Tca-8113 cells by immunofluorescence. We further observed autophagy vacuoles by monodansylcadaverine staining. We found that RAGE blockade and cisplatin significantly decreased cell viability and increased the cell apoptosis rate compared with cisplatin alone. Furthermore, RAGE blockade suppressed the canonical Wnt pathway proteins β-catenin and GSK-3β, but upregulated noncanonical WNT5A and receptor ROR-2. We show that RAGE blockade suppressed the levels of autophagy-related protein LC3II/I, beclin1, accelerated degradation of autophagy for the increasing p62 expression, and increased cell apoptosis for the increasing expressions of cleaved caspase-3 and bcl-2-associated X proteins. We observed the location of WNT5A and beclin1 expressions on cells by immunofluorescence and their trends were consistent with western blotting. Taken together, our findings suggested that RAGE blockade+cisplatin improved chemotherapeutic effects by reducing autophagy and regulating Wnt/β-catenin to suppress the progression of TSCC.

  8. Activation of the sympathetic nervous system mediates hypophagic and anxiety-like effects of CB₁ receptor blockade.

    PubMed

    Bellocchio, Luigi; Soria-Gómez, Edgar; Quarta, Carmelo; Metna-Laurent, Mathilde; Cardinal, Pierre; Binder, Elke; Cannich, Astrid; Delamarre, Anna; Häring, Martin; Martín-Fontecha, Mar; Vega, David; Leste-Lasserre, Thierry; Bartsch, Dusan; Monory, Krisztina; Lutz, Beat; Chaouloff, Francis; Pagotto, Uberto; Guzman, Manuel; Cota, Daniela; Marsicano, Giovanni

    2013-03-19

    Complex interactions between periphery and the brain regulate food intake in mammals. Cannabinoid type-1 (CB1) receptor antagonists are potent hypophagic agents, but the sites where this acute action is exerted and the underlying mechanisms are not fully elucidated. To dissect the mechanisms underlying the hypophagic effect of CB1 receptor blockade, we combined the acute injection of the CB1 receptor antagonist rimonabant with the use of conditional CB1-knockout mice, as well as with pharmacological modulation of different central and peripheral circuits. Fasting/refeeding experiments revealed that CB1 receptor signaling in many specific brain neurons is dispensable for the acute hypophagic effects of rimonabant. CB1 receptor antagonist-induced hypophagia was fully abolished by peripheral blockade of β-adrenergic transmission, suggesting that this effect is mediated by increased activity of the sympathetic nervous system. Consistently, we found that rimonabant increases gastrointestinal metabolism via increased peripheral β-adrenergic receptor signaling in peripheral organs, including the gastrointestinal tract. Blockade of both visceral afferents and glutamatergic transmission in the nucleus tractus solitarii abolished rimonabant-induced hypophagia. Importantly, these mechanisms were specifically triggered by lipid-deprivation, revealing a nutrient-specific component acutely regulated by CB1 receptor blockade. Finally, peripheral blockade of sympathetic neurotransmission also blunted central effects of CB1 receptor blockade, such as fear responses and anxiety-like behaviors. These data demonstrate that, independently of their site of origin, important effects of CB1 receptor blockade are expressed via activation of peripheral sympathetic activity. Thus, CB1 receptors modulate bidirectional circuits between the periphery and the brain to regulate feeding and other behaviors.

  9. Endocannabinoid receptor blockade reduces alanine aminotransferase in polycystic ovary syndrome independent of weight loss.

    PubMed

    Dawson, Alison J; Kilpatrick, Eric S; Coady, Anne-Marie; Elshewehy, Abeer M M; Dakroury, Youssra; Ahmed, Lina; Atkin, Stephen L; Sathyapalan, Thozhukat

    2017-07-14

    Evidence suggests that endocannabinoid system activation through the cannabinoid receptor 1 (CB1) is associated with enhanced liver injury, and CB1 antagonism may be beneficial. The aim of this study was to determine the impact of rimonabant (CB1 antagonist) on alanine aminotransferase (ALT), a hepatocellular injury marker, and a hepatic inflammatory cytokine profile. Post hoc review of 2 studies involving 50 obese women with PCOS and well matched for weight, randomised to weight reducing therapy; rimonabant (20 mg od) or orlistat (120 mg tds), or to insulin sensitising therapy metformin, (500 mg tds), or pioglitazone (45 mg od). No subject had non-alcoholic fatty liver disease (NAFLD). Treatment with rimonabant for 12 weeks reduced both ALT and weight (p < 0.01), and there was a negative correlation between Δ ALT and Δ HOMA-IR (p < 0.001), but not between Δ ALT and Δ weight. There was a significant reduction of weight with orlistat (p < 0.01); however, orlistat, metformin and pioglitazone had no effect on ALT. The free androgen index fell in all groups (p < 0.05). The inflammatory marker hs-CRP was reduced by pioglitazone (p < 0.001) alone and did not correlate with changes in ALT. The inflammatory cytokine profile for IL-1β, IL-6, IL-7, IL-10, IL12, TNF-α, MCP-1 and INF-γ did not differ between groups. None of the interventions had an effect on biological variability of ALT. Rimonabant through CB1 receptor blockade decreased serum ALT that was independent of weight loss and hepatic inflammatory markers in obese women with PCOS without NAFLD. ISRCTN58369615 (February 2007; retrospectively registered) ISRCTN75758249 (October 2007; retrospectively registered).

  10. Antipsychotic drugs reverse the disruption in prefrontal cortex function produced by NMDA receptor blockade with phencyclidine

    PubMed Central

    Kargieman, Lucila; Santana, Noemí; Mengod, Guadalupe; Celada, Pau; Artigas, Francesc

    2007-01-01

    NMDA receptor (NMDA-R) antagonists are extensively used as schizophrenia models because of their ability to evoke positive and negative symptoms as well as cognitive deficits similar to those of the illness. Cognitive deficits in schizophrenia are associated with prefrontal cortex (PFC) abnormalities. These deficits are of particular interest because an early improvement in cognitive performance predicts a better long-term clinical outcome. Here, we examined the effect of the noncompetitive NMDA-R antagonist phencyclidine (PCP) on PFC function to understand the cellular and network elements involved in its schizomimetic actions. PCP induces a marked disruption of the activity of the PFC in the rat, increasing and decreasing the activity of 45% and 33% of the pyramidal neurons recorded, respectively (22% of the neurons were unaffected). Concurrently, PCP markedly reduced cortical synchrony in the delta frequency range (0.3–4 Hz) as assessed by recording local field potentials. The subsequent administration of the antipsychotic drugs haloperidol and clozapine reversed PCP effects on pyramidal cell firing and cortical synchronization. PCP increased c-fos expression in PFC pyramidal neurons, an effect prevented by the administration of clozapine. PCP also enhanced c-fos expression in the centromedial and mediodorsal (but not reticular) nuclei of the thalamus, suggesting the participation of enhanced thalamocortical excitatory inputs. These results shed light on the involvement of PFC in the schizomimetic action of NMDA-R antagonists and show that antipsychotic drugs may partly exert their therapeutic effect by normalizing a disrupted PFC activity, an effect that may add to subcortical dopamine receptor blockade. PMID:17785415

  11. Blockade of substantia nigra dopamine D1 receptors reduces intravenous cocaine reward in rats.

    PubMed

    Quinlan, Matthew G; Sharf, Ruth; Lee, David Y; Wise, Roy A; Ranaldi, Robert

    2004-08-01

    We have recently found that blockade of dopamine D1-type receptors in the ventral tegmental area reduces the rewarding effects of intravenous cocaine; here, we explored the possibility that blockade of D1 receptors in the adjacent substantia nigra (SN)--not usually considered part of reward circuitry--might have similar effects. To test the hypothesis that blockade of dopamine D1 receptors in the SN reduces the rewarding effects of cocaine. Twenty one rats were prepared with intravenous catheters and with bilateral guide cannulae implanted such that injections could be made directly into the SN or just dorsal to the SN. The rats were trained to self-administer intravenous cocaine (1.0 mg/kg per injection) on a fixed-ratio 1 (FR1) schedule of reinforcement. After stable responding developed, 13 of the animals were tested following pretreatment with bilateral microinjections of SCH 23390 at doses of 0, 1, 2 or 4 microg/0.5 microl into the SN and 8 were tested with injections of 0 microg or 4 microg/0.5 microl into a site 2 mm dorsal to the SN site. Microinjections of SCH 23390 in the SN significantly increased rates of cocaine self-administration, while injections dorsal to SN had no significant effect on responding. These data suggest that blockade of dendritically released DA in the SN reduces the rewarding effects of cocaine. These findings complement accumulating evidence that the rewarding effects of cocaine are not restricted to the drug's ability to elevate dopamine levels in the nucleus accumbens.

  12. Acute and chronic systemic CB1 cannabinoid receptor blockade improves blood pressure regulation and metabolic profile in hypertensive (mRen2)27 rats.

    PubMed

    Schaich, Chris L; Shaltout, Hossam A; Brosnihan, K Bridget; Howlett, Allyn C; Diz, Debra I

    2014-08-01

    We investigated acute and chronic effects of CB1 cannabinoid receptor blockade in renin-angiotensin system-dependent hypertension using rimonabant (SR141716A), an orally active antagonist with central and peripheral actions. In transgenic (mRen2)27 rats, a model of angiotensin II-dependent hypertension with increased body mass and insulin resistance, acute systemic blockade of CB1 receptors significantly reduced blood pressure within 90 min but had no effect in Sprague-Dawley rats. No changes in metabolic hormones occurred with the acute treatment. During chronic CB1 receptor blockade, (mRen2)27 rats received daily oral administration of SR141716A (10 mg/kg/day) for 28 days. Systolic blood pressure was significantly reduced within 24 h, and at Day 21 of treatment values were 173 mmHg in vehicle versus 149 mmHg in drug-treated rats (P < 0.01). This accompanied lower cumulative weight gain (22 vs. 42 g vehicle; P < 0.001), fat mass (2.0 vs. 2.9% of body weight; P < 0.05), and serum leptin (2.8 vs. 6.0 ng/mL; P < 0.05) and insulin (1.0 vs. 1.9 ng/mL; P < 0.01), following an initial transient decrease in food consumption. Conscious hemodynamic recordings indicate twofold increases occurred in spontaneous baroreflex sensitivity (P < 0.05) and heart rate variability (P < 0.01), measures of cardiac vagal tone. The beneficial actions of CB1 receptor blockade in (mRen2)27 rats support the interpretation that an upregulated endocannabinoid system contributes to hypertension and impaired autonomic function in this angiotensin II-dependent model. We conclude that systemic CB1 receptor blockade may be an effective therapy for angiotensin II-dependent hypertension and associated metabolic syndrome.

  13. Adenosine A2A Receptor Blockade Prevents Rotenone-Induced Motor Impairment in a Rat Model of Parkinsonism

    PubMed Central

    Fathalla, Ahmed M.; Soliman, Amira M.; Ali, Mohamed H.; Moustafa, Ahmed A.

    2016-01-01

    Pharmacological studies implicate the blockade of adenosine receptorsas an effective strategy for reducing Parkinson’s disease (PD) symptoms. The objective of this study is to elucidate the possible protective effects of ZM241385 and 8-cyclopentyl-1, 3-dipropylxanthine, two selective A2A and A1 receptor antagonists, on a rotenone rat model of PD. Rats were split into four groups: vehicle control (1 ml/kg/48 h), rotenone (1.5 mg/kg/48 h, s.c.), ZM241385 (3.3 mg/kg/day, i.p) and 8-cyclopentyl-1, 3-dipropylxanthine (5 mg/kg/day, i.p). After that, animals were subjected to behavioral (stride length and grid walking) and biochemical (measuring concentration of dopamine levels using high performance liquid chromatography, HPLC). In the rotenone group, rats displayed a reduced motor activity and disturbed movement coordination in the behavioral tests and a decreased dopamine concentration as foundby HPLC. The effect of rotenone was partially prevented in the ZM241385 group, but not with 8-cyclopentyl-1,3-dipropylxanthine administration. The administration of ZM241385 improved motor function and movement coordination (partial increase of stride length and partial decrease in the number of foot slips) and an increase in dopamine concentration in the rotenone-injected rats. However, the 8-cyclopentyl-1,3-dipropylxanthine and rotenone groups were not significantly different. These results indicate that selective A2A receptor blockade by ZM241385, but not A1 receptor blockadeby 8-cyclopentyl-1,3-dipropylxanthine, may treat PD motor symptoms. This reinforces the potential use of A2A receptor antagonists as a treatment strategy for PD patients. PMID:26973484

  14. Androgen receptor blockade using flutamide skewed sex ratio of litters in mice

    PubMed Central

    Gharagozlou, Faramarz; Youssefi, Reza; Vojgani, Mehdi; Akbarinejad, Vahid; Rafiee, Ghazaleh

    2016-01-01

    Maternal testosterone has been indicated to affect sex ratio of offspring. The present study was conducted to elucidate the role of androgen receptor in this regard by blockade of androgen receptor using flutamide in female mice. Mice were randomly assigned to two experimental groups. Mice in the control (n = 20) and treatment (n = 20) groups received 8 IU equine chorionic gonadotropin (eCG) followed by human chorionic gonadotropin (hCG) injection (8 IU) 47 hr later. In addition, mice in the control and treatment groups received four injections of ethanol-saline vehicle and flutamide solution (2.50 mg), respectively, started from 1 hr before eCG injection until hCG injection at 12-hr intervals. Conception rate was not different between the treatment (18/20: 90.00%) and control (19/20: 95.00%) groups (p > 0.05). Litter size was higher in the treatment (8.22 ± 0.26) than control (7.21 ± 0.28) group (p < 0.05). Male sex ratio was lower in the flutamide-treated mice (67/148: 45.30%) as compared with the untreated ones (80/137: 58.40%; odds ratio = 1.69; p < 0.05). In conclusion, the results showed that androgen receptor blockade could skew sex ratio of offspring toward females implying that the effect of testosterone on sex ratio might be through binding to androgen receptor. In addition, the blockade of androgen receptor using flutamide appeared to enhance litter size. PMID:27482363

  15. Effects of dual endothelin receptor blockade on sympathetic activation and arrhythmogenesis during acute myocardial infarction in rats.

    PubMed

    Kolettis, Theofilos M; Baltogiannis, Giannis G; Tsalikakis, Dimitrios G; Tzallas, Alexandros T; Agelaki, Maria G; Fotopoulos, Andreas; Fotiadis, Dimitrios I; Kyriakides, Zenon S

    2008-02-02

    The effects of dual (ETA and ETB) endothelin receptor blockade on ventricular arrhythmogenesis during acute myocardial infarction are not well defined. We randomly allocated Wistar rats to bosentan (100 mg/kg daily, n=24), a dual endothelin receptor antagonist, or vehicle (n=23). After 7 days of treatment, myocardial infarction was induced by permanent coronary ligation. Ventricular tachyarrhythmias were evaluated for 24 h following ligation, using a miniature telemetry electrocardiogram recorder. Action potential duration was measured from monophasic epicardial recordings and sympathetic activation was assessed by heart rate variability and catecholamine serum level measurements. Compared to controls (1012+/-185 s), bosentan (59+/-24 s) markedly decreased (P<0.00001) the total duration of ventricular tachyarrhythmias during the delayed (1-24 h) phase post-ligation, with a modest effect during the early (0-1 h) phase (132+/-38 s, versus 43+/-18 s, respectively, P=0.053). Treatment did not affect infarct size or total mortality. Action potential duration at 90% repolarization prolonged in controls (from 93.1+/-4.7 ms to 117.6+/-6.9 ms), displaying increased temporal dispersion (from 4.14+/-0.45 ms to 10.42+/-2.51 ms, both P<0.001), but was preserved in treated animals. Bosentan decreased norepinephrine, but increased epinephrine levels 24 h post-ligation. Low frequency spectra of heart rate variability, an index of net sympathetic tone, were lower in bosentan-treated rats. Dual endothelin-1 receptor blockade decreases ventricular tachyarrhythmias during myocardial infarction without reperfusion, by preventing repolarization inhomogeneity. Diverse treatment effects on sympathetic activation may ameliorate the antiarrhythmic action.

  16. Blockade of porcine carotid vascular response to sumatriptan by GR 127935, a selective 5-HT1D receptor antagonist.

    PubMed Central

    De Vries, P.; Heiligers, J. P.; Villalón, C. M.; Saxena, P. R.

    1996-01-01

    1. It has previously been shown that the antimigraine drug, sumatriptan, a putative 5-HT1D receptor agonist, decreases porcine common carotid and arteriovenous anastomotic blood flows, but slightly increases the arteriolar (capillary) blood flow to the skin and ears. Interestingly, such responses, being mediated by 5-HT1-like receptors, are resistant to blockade by metergoline, which, in addition to displaying a very high affinity for (and occasionally intrinsic efficacy at) the 5-HT1D receptor subtypes, blocks (with lower potency than methiothepin) some 5-HT1D receptor-mediated vascular responses. These findings raise doubts whether sumatriptan-sensitive 5-HT1-like receptors mediating changes in the distribution of porcine carotid blood flow are identical to cloned 5-HT1D receptors. With the recent advent of the potent and selective 5-HT1D receptor antagonist, GR127935, we have examined in the present study whether the carotid vascular effects of sumatriptan in the pig are amenable to blockade by GR127935. 2. In animals pretreated with saline, sumatriptan (30, 100 and 300 micrograms kg-1, i.v.) reduced the total carotid and arteriovenous anastomotic blood flows in a dose dependent manner. In contrast, sumatriptan increased blood flow to the skin, ears and fat, although the total capillary fraction was not significantly affected. 3. While GR127935 pretreatment (0.25 and 0.5 mg kg-1) itself slightly reduced the total carotid and arteriovenous anastomotic blood flows, carotid vasoconstrictor responses to sumatriptan were either partly (0.25 mg kg-1) or completely (0.5 mg kg-1) blocked by the compound. In GR127935 pretreated animals, the sumatriptan-induced increases in blood flow to the skin, ears and fat were also attenuated. 4. Taken together, the results suggest that arteriovenous anastomotic constriction and, possibly, arteriolar dilatation in the skin, ears and fat by sumatriptan are mediated by 5-HT1D receptors. Therefore, vascular 5-HT1-like receptors in the

  17. Oncogenic fingerprint of epidermal growth factor receptor pathway and emerging epidermal growth factor receptor blockade resistance in colorectal cancer

    PubMed Central

    Sobani, Zain A; Sawant, Ashwin; Jafri, Mikram; Correa, Amit Keith; Sahin, Ibrahim Halil

    2016-01-01

    Epidermal growth factor receptor (EGFR) has been an attractive target for treatment of epithelial cancers, including colorectal cancer (CRC). Evidence from clinical trials indicates that cetuximab and panitumumab (anti-EGFR monoclonal antibodies) have clinical activity in patients with metastatic CRC. The discovery of intrinsic EGFR blockade resistance in Kirsten RAS (KRAS)-mutant patients led to the restriction of anti-EGFR antibodies to KRAS wild-type patients by Food and Drug Administration and European Medicine Agency. Studies have since focused on the evaluation of biomarkers to identify appropriate patient populations that may benefit from EGFR blockade. Accumulating evidence suggests that patients with mutations in EGFR downstream signaling pathways including KRAS, BRAF, PIK3CA and PTEN could be intrinsically resistant to EGFR blockade. Recent whole genome studies also suggest that dynamic alterations in signaling pathways downstream of EGFR leads to distinct oncogenic signatures and subclones which might have some impact on emerging resistance in KRAS wild-type patients. While anti-EGFR monoclonal antibodies have a clear potential in the management of a subset of patients with metastatic CRC, further studies are warranted to uncover exact mechanisms related to acquired resistance to EGFR blockade. PMID:27777877

  18. Orchiectomy or androgen receptor blockade attenuates baroreflex-mediated bradycardia in conscious rats

    PubMed Central

    Ward, Gregg R; Abdel-Rahman, Abdel A

    2006-01-01

    Background Previous studies have shown that testosterone enhances baroreflex bradycardia. Therefore, conscious unrestrained rats were used to investigate the role of the androgen receptor in the testosterone-mediated modulation of baroreflex bradycardia. Androgen depletion (3 weeks), and androgen receptor blockade (20–24 h), were implemented to test the hypothesis that testosterone influences baroreflex bradycardia via its activity at the androgen receptor in male rats. Phenylephrine (1–16 μg kg-1) was used to assess baroreflex bradycardia. Results Androgen depletion attenuated baroreflex bradycardia (P < 0.01). The antiandrogen flutamide (5, 15, or 30 mg kg-1, s.c.) caused dose-related attenuation of baroreflex bradycardia in spite of a significant (P < 0.05) increase in serum testosterone. The latter did not lead to increased serum 17β-estradiol level. Conclusion The data suggest: 1) Androgen depletion or adequate androgen receptor blockade attenuates baroreflex bradycardia. 2) The reflex increase in serum testosterone may counterbalance the action of the lower doses (5 or 15 mg kg-1) of flutamide. 3) The absence of a change in serum 17β-estradiol rules out its contribution to flutamide action on baroreflex bradycardia. PMID:16430770

  19. Adenosine A1, but not A2, receptor blockade increases anxiety and arousal in Zebrafish.

    PubMed

    Maximino, Caio; Lima, Monica G; Olivera, Karen R M; Picanço-Diniz, Domingos L W; Herculano, Anderson M

    2011-09-01

    Adenosinergic systems have been implicated in anxiety-like states, as caffeine can induce a state of anxiety in human beings. Caffeine is an antagonist at A(1) and A(2) adenosine receptors but it remains unclear whether anxiety is mediated by one or both of these. As the adenosinergic system is rather conserved, we opted to pursue these questions using zebrafish, a widely used model organism in genetics and developmental biology. Zebrafish adenosine 1. 2A.1 and 2A.2 receptors conserve histidine residues in TM6 and TM7 that are responsible for affinity in bovine A1 receptor. We investigated the effects of caffeine, PACPX (an A(1) receptor antagonist) and 1,3-dimethyl-1-propargylxanthine (DMPX) (an A(2) receptor antagonist) on anxiety-like behaviour and locomotor activity of zebrafish in the scototaxis test as well as evaluated the effects of these drugs on pigment aggregation. Caffeine increased anxiety at the dose of 100 mg/kg, while locomotion at the dose of 10 mg/kg was increased. Both doses of 10 and 100 mg/kg induced pigment aggregation. PACPX, on the other hand, increased anxiety at a dose of 6 mg/kg and induced pigment aggregation at the doses of 0.6 and 6 mg/kg, but did not produce a locomotor effect. DMPX, in turn, increased locomotion at the dose of 6 mg/kg but did not produce any effect on pigment aggregation or anxiety-like behaviour. These results indicate that blockade of A(1)-R, but not A(2)-R, induces anxiety and autonomic arousal, while the blockade of A(2)-R induces hyperlocomotion. Thus, as in rodents, caffeine's anxiogenic and arousing effects are probably mediated by A(1) receptors in zebrafish and its locomotor activating effect is probably mediated by A(2) receptors. © 2011 The Authors. Basic & Clinical Pharmacology & Toxicology © 2011 Nordic Pharmacological Society.

  20. BENEFICIAL EFFECTS OF MINERALOCORTICOID RECEPTOR BLOCKADE IN EXPERIMENTAL NON-ALCOHOLIC STEATOHEPATITIS

    PubMed Central

    Pizarro, Margarita; Solís, Nancy; Quintero, Pablo; Barrera, Francisco; Cabrera, Daniel; Santiago, Pamela Rojasde; Arab, Juan Pablo; Padilla, Oslando; Roa, Juan Carlos; Moshage, Han; Wree, Alexander; Inzaugarat, Eugenia; Feldstein, Ariel E.; Fardella, Carlos E.; Baudrand, Rene; Riquelme, Arnoldo; Arrese, Marco

    2015-01-01

    Background Therapeutic options to treat Non-alcoholic steatohepatitis (NASH) are limited. Mineralocorticoid receptor (MR) activation could play a role in hepatic fibrogenesis and its modulation could be beneficial for NASH. Aim To investigate whether eplerenone, a specific MR antagonist, ameliorates liver damage in experimental NASH. Methods C57bl6 mice were fed a choline-deficient-amino-acid–defined (CDAA) diet for 22 weeks with or without eplerenone supplementation. Serum levels of aminotransferases and aldosterone were measured and hepatic steatosis, inflammation, and fibrosis scored histologically. Hepatic triglyceride content (HTC) and hepatic mRNA levels of pro-inflammatory pro-fibrotic, oxidative stress-associated genes and of MR were also assessed. Results CDAA diet effectively induced fibrotic NASH, and increased the hepatic expression of pro-inflammatory, pro-fibrotic and oxidative stress-associated genes. Hepatic MR mRNA levels significantly correlated with the expression of pro-inflammatory and pro-fibrotic genes and were significantly increased in hepatic stellate cells obtained from CDAA-fed animals. Eplerenone administration was associated to a reduction in histological steatosis and attenuation of liver fibrosis development, which was associated to a significant decrease in the expression of collagen-α1, collagen type III, alpha 1 and Matrix metalloproteinase-2. Conclusion The expression of MR correlates with inflammation and fibrosis development in experimental NASH. Specific MR blockade with eplerenone has hepatic anti-steatotic and anti-fibrotic effects. These data identifies eplerenone as a potential novel therapy for NASH. Considering its safety and FDA-approved status, human studies are warranted PMID:25646700

  1. β-Adrenergic receptor blockade impairs coronary exercise hyperemia in young men but not older men

    PubMed Central

    Ross, Amanda J.; Gao, Zhaohui; Pollock, Jonathan P.; Leuenberger, Urs A.; Sinoway, Lawrence I.

    2014-01-01

    Patients with coronary artery disease have attenuated coronary vasodilator responses to physiological stress, which is partially attributed to a β-adrenergic receptor (β-AR)-mediated mechanisms. Whether β-ARs contribute to impaired coronary vasodilation seen with healthy aging is unknown. The purpose of this study was to investigate the role of β-ARs in coronary exercise hyperemia in healthy humans. Six young men (26 ± 1 yr) and seven older men (67 ± 4 yr) performed isometric handgrip exercise at 30% maximal voluntary contraction for 2 min after receiving intravenous propranolol, a β-AR antagonist, and no treatment. Isoproterenol, a β-AR agonist, was infused to confirm the β-AR blockade. Blood pressure and heart rate were monitored continuously, and coronary blood flow velocity (CBV, left anterior descending artery) was measured by transthoracic Doppler echocardiography. Older men had an attenuated ΔCBV to isometric exercise (3.8 ± 1.3 vs. 9.7 ± 2.1 cm/s, P = 0.02) compared with young men. Propranolol decreased the ΔCBV at peak handgrip exercise in young men (9.7 ± 2.1 vs. 2.7 ± 0.9 cm/s, P = 0.008). However, propranolol had no effect on ΔCBV in older men (3.8 ± 1.3 vs. 4.2 ± 1.9 cm/s, P = 0.9). Older men also had attenuated coronary hyperemia to low-dose isoproterenol. These data indicate that β-AR control of coronary blood flow is impaired in healthy older men. PMID:25239806

  2. [Comparative analysis of metabotropic and ionotropic glutamate striatal receptors blockade influence on rats locomotor behaviour].

    PubMed

    Iakimovskiĭ, A F; Kerko, T V

    2013-02-01

    The influence of NMDA and metabotropic neostriatal glutamate receptors blockade to avoidance conditioning (in shuttle box) and free locomotor behavior (in open field) in chronic experiments in rats were investigated. The glutamate receptor antagonists were injected bilateral into striatum separately and with the GABA-A receptor antagonist picrotoxin (2 microg), that produced in rats the impairment of avoidance conditioning and choreo-myoklonic hyperkinesis. The most effective in preventing of negative picrotoxin influence on behavior was 5-type metabotropic glutamate receptors antagonist MTEP (3 microg). Separately injected MTEP did not influence on avoidance conditioning and free locomotor behavior. Unlike that, 1-type metabotropic glutamate receptors antagonist EMQMCM (3 microg) impaired normal locomotor behavior and did not prevent the picrotoxin effects. The NMDA glutamate receptors MK 801 (disocilpin--1 and 5 microg) impaired the picrotoxin-induced hyperkinesis, but did not to prevent the negative effects on avoidance conditioning; separately injected MK 801 reduced free locomotor activity. Based on location of investigated receptor types in neostriatal neurons membranes, we proposed that the most effective influence on 5-type metabotropic glutamate receptors is associated with their involvement in "indirect" efferent pathway, suffered in hyperkinetic extrapyramidal motor dysfunction--Huntington's chorea in human.

  3. Effects of mineralocorticoid receptor blockade on empathy in patients with major depressive disorder.

    PubMed

    Wingenfeld, Katja; Kuehl, Linn K; Dziobek, Isabel; Roepke, Stefan; Otte, Christian; Hinkelmann, Kim

    2016-10-01

    The mineralocorticoid receptor (MR) is highly expressed in the hippocampus and prefrontal cortex and is involved in social cognition. We recently found that pharmacological stimulation of the MR enhances emotional empathy but does not affect cognitive empathy. In the current study, we examined whether blockade of the MR impairs empathy in patients with major depressive disorder (MDD) and healthy individuals. In a placebo-controlled study, we randomized 28 patients with MDD without psychotropic medication and 43 healthy individuals to either placebo or 300 mg spironolactone, a MR antagonist. Subsequently, all participants underwent two tests of social cognition, the Multifaceted Empathy Test (MET) and the Movie for the Assessment of Social Cognition (MASC), measuring cognitive and emotional facets of empathy. In the MET, we found no significant main effect of treatment or main effect of group for cognitive empathy but a highly significant treatment by group interaction (p < 0.01). Patients had higher cognitive empathy scores compared to controls in the placebo condition but not after spironolactone. Furthermore, in the spironolactone condition reduced cognitive empathy was seen in MDD patients but not in controls. Emotional empathy was not affected by MR blockade. In the MASC, no effect of spironolactone could be revealed. Depressed patients appear to exhibit greater cognitive empathy compared to healthy individuals. Blockade of MR reduced cognitive empathy in MDD patients to the level of healthy individuals. Future studies should further clarify the impact of MR functioning on different domains of social cognition in psychiatric patients.

  4. Pharmacological blockade of the vanilloid receptor TRPV1 elicits marked hyperthermia in humans.

    PubMed

    Gavva, Narender R; Treanor, James J S; Garami, Andras; Fang, Liang; Surapaneni, Sekhar; Akrami, Anna; Alvarez, Francisco; Bak, Annette; Darling, Mary; Gore, Anu; Jang, Graham R; Kesslak, James P; Ni, Liyun; Norman, Mark H; Palluconi, Gabrielle; Rose, Mark J; Salfi, Margaret; Tan, Edward; Romanovsky, Andrej A; Banfield, Christopher; Davar, Gudarz

    2008-05-01

    The vanilloid receptor TRPV1 has been identified as a molecular target for the treatment of pain associated with inflammatory diseases and cancer. Hence, TRPV1 antagonists have been considered for therapeutic evaluation in such diseases. During Phase I clinical trials with AMG 517, a highly selective TRPV1 antagonist, we found that TRPV1 blockade elicited marked, but reversible, and generally plasma concentration-dependent hyperthermia. Similar to what was observed in rats, dogs, and monkeys, hyperthermia was attenuated after repeated dosing of AMG 517 (at the highest dose tested) in humans during a second Phase I trial. However, AMG 517 administered after molar extraction (a surgical cause of acute pain) elicited long-lasting hyperthermia with maximal body temperature surpassing 40 degrees C, suggesting that TRPV1 blockade elicits undesirable hyperthermia in susceptible individuals. Mechanisms of AMG 517-induced hyperthermia were then studied in rats. AMG 517 caused hyperthermia by inducing tail skin vasoconstriction and increasing thermogenesis, which suggests that TRPV1 regulates vasomotor tone and metabolic heat production. In conclusion, these results demonstrate that: (a) TRPV1-selective antagonists like AMG 517 cannot be developed for systemic use as stand alone agents for treatment of pain and other diseases, (b) individual susceptibility influences magnitude of hyperthermia observed after TRPV1 blockade, and (c) TRPV1 plays a pivotal role as a molecular regulator for body temperature in humans.

  5. Alpha-adrenergic receptor blockade by phentolamine increases the efficacy of vasodilators in penile corpus cavernosum.

    PubMed

    Kim, N N; Goldstein, I; Moreland, R B; Traish, A M

    2000-03-01

    Penile trabecular smooth muscle tone, a major determinant of erectile function, is highly regulated by numerous inter- and intracellular pathways. The interaction between pathways mediating contraction and relaxation has not been studied in detail. To this end, we investigated the functional effects of alpha adrenergic receptor blockade with phentolamine and its interaction with vasodilators (sildenafil, vasoactive intestinal polypeptide (VIP) and PGE1) that elevate cyclic nucleotides on penile cavernosal smooth muscle contractility. In organ bath preparations of cavernosal tissue strips contracted with phenylephrine, phentolamine significantly enhanced relaxation induced by sildenafil, VIP and PGE1. Sildenafil, VIP or PGE1 also significantly enhanced relaxation induced by phentolamine in cavernosal tissue strips contracted with phenylephrine. To study the effects of alpha adrenergic receptor blockade and modification of cyclic nucleotide metabolism during active neurogenic input, cavernosal tissue strips in organ bath preparations were contracted with the non-adrenergic agonist endothelin-1 and subjected to electrical field stimulation (EFS) in the absence or presence of phentolamine and/or sildenafil. EFS (5-40Hz) typically caused biphasic relaxation and contraction responses. Phentolamine alone enhanced relaxation and reduced or prevented contraction to EFS. Sildenafil enhanced relaxation to EFS at lower frequencies (< or = 5 Hz). The combination of phentolamine and sildenafil enhanced EFS-induced relaxation at all frequencies tested. EFS, in the presence of 10 nM phentolamine and 30 nM sildenafil, produced enhanced relaxation responses which were quantitatively similar to those obtained in the presence of 50 nM sildenafil alone. Thus, blockade of alpha-adrenergic receptors with phentolamine increases the efficacy of cyclic nucleotide-dependent vasodilators. Furthermore, phentolamine potentiates relaxation and attenuates contraction in response to endogenous

  6. Endothelin receptor a blockade is an ineffective treatment for adriamycin nephropathy.

    PubMed

    Tan, Roderick J; Zhou, Lili; Zhou, Dong; Lin, Lin; Liu, Youhua

    2013-01-01

    Endothelin is a vasoconstricting peptide that plays a key role in vascular homeostasis, exerting its biologic effects via two receptors, the endothelin receptor A (ETA) and endothelin receptor B (ETB). Activation of ETA and ETB has opposing actions, in which hyperactive ETA is generally vasoconstrictive and pathologic. Selective ETA blockade has been shown to be beneficial in renal injuries such as diabetic nephropathy and can improve proteinuria. Atrasentan is a selective pharmacologic ETA blocker that preferentially inhibits ETA activation. In this study, we evaluated the efficacy of ETA blockade by atrasentan in ameliorating proteinuria and kidney injury in murine adriamycin nephropathy, a model of human focal segmental glomerulosclerosis. We found that ETA expression was unaltered during the course of adriamycin nephropathy. Whether initiated prior to injury in a prevention protocol (5 mg/kg/day, i.p.) or after injury onset in a therapeutic protocol (7 mg/kg or 20 mg/kg three times a week, i.p.), atrasentan did not significantly affect the initiation and progression of adriamycin-induced albuminuria (as measured by urinary albumin-to-creatinine ratios). Indices of glomerular damage were also not improved in atrasentan-treated groups, in either the prevention or therapeutic protocols. Atrasentan also failed to improve kidney function as determined by serum creatinine, histologic damage, and mRNA expression of numerous fibrosis-related genes such as collagen-I and TGF-β1. Therefore, we conclude that selective blockade of ETA by atrasentan has no effect on preventing or ameliorating proteinuria and kidney injury in adriamycin nephropathy.

  7. Potential effect of angiotensin II receptor blockade in adipose tissue and bone.

    PubMed

    Nakagami, Hironori; Osako, Mariana Kiomy; Morishita, Ryuichi

    2013-01-01

    Recent evidence demonstrated that dysregulation of adipocytokine functions seen in abdominal obesity may be involved in the pathogenesis of the metabolic syndrome. Angiotensinogen, the precursor of angiotensin (Ang) II, is produced primarily in the liver, and also in adipose tissue, where it is up-regulated during the development of obesity and involved in blood pressure regulation and adipose tissue growth. Blockade of renin-angiotensin system (RAS) attenuates weight gain and adiposity by enhanced energy expenditure, and the favorable metabolic effects of telmisartan have been related to its Ang II receptor blockade and action as a partial agonist of peroxisome proliferators activated receptor (PPAR)-γ. PPARγ plays an important role in regulating carbohydrate and lipid metabolism, and ligands for PPARγ can improve insulin sensitivity and reduce triglyceride levels. Similarly, bone metabolism is closely regulated by hormones and cytokines, which have effects on both bone resorption and deposition. It is known that the receptors of Ang II are expressed in culture osteoclasts and osteoblasts, and Ang II is postulated to be able to act upon the cells involved in bone metabolism. In in vitro system, Ang II induced the differentiation and activation of osteoclasts responsible for bone resorption. Importantly, it was demonstrated by the sub-analysis of a recent clinical study that the fracture risk was significantly reduced by the usage of angiotensin-converting enzyme inhibitors. To treat the subgroups of hypertensive patients with osteoporosis RAS can be considered a novel target.

  8. Effects of semax against the background of dopaminergic receptor blockade with haloperidol.

    PubMed

    Sebentsova, E A; Levitskaya, N G; Andreeva, L A; Alfeeva, L Yu; Kamenskii, A A; Myasoedov, N F

    2006-02-01

    We studied the neurotropic effects of ACTH(4-10) analog semax against the background of dopaminergic receptors blockade with haloperidol. Intranasal administration of semax (0.05, 0.2, and 0.6 mg/kg) produced virtually no effect on disturbances of orientation and exploratory reactions and motor activity caused by intraperitoneal injection of 0.2 mg/kg haloperidol. By contrast, preliminary administration of 0.05 mg/kg semax prevented haloperidol-induced disturbances in active avoidance conditioning.

  9. CTLA-4 blockade decreases TGF-β, IDO, and viral RNA expression in tissues of SIVmac251-infected macaques

    PubMed Central

    Hryniewicz, Anna; Boasso, Adriano; Edghill-Smith, Yvette; Vaccari, Monica; Fuchs, Dietmar; Venzon, David; Nacsa, Janos; Betts, Michael R.; Tsai, Wen-Po; Heraud, Jean-Michel; Beer, Brigitte; Blanset, Diann; Chougnet, Claire; Lowy, Israel; Shearer, Gene M.; Franchini, Genoveffa

    2006-01-01

    Regulatory T (Treg) cells are a subset of CD25+CD4+ T cells that constitutively express high levels of cytotoxic T lymphocyte antigen-4 (CTLA-4) and suppress T-cell activation and effector functions. Treg cells are increased in tissues of individuals infected with HIV-1 and macaques infected with simian immunodeficiency virus (SIVmac251). In HIV-1 infection, Treg cells could exert contrasting effects: they may limit viral replication by decreasing immune activation, or they may increase viral replication by suppressing virusspecific immune response. Thus, the outcome of blocking Treg function in HIV/SIV should be empirically tested. Here, we demonstrate that CD25+ T cells inhibit virus-specific T-cell responses in cultured T cells from blood and lymph nodes of SIV-infected macaques. We investigated the impact of CTLA-4 blockade using the anti–CTLA-4 human antibody MDX-010 in SIV-infected macaques treated with antiretroviral therapy (ART). CTLA-4 blockade decreased expression of the tryptophan-depleting enzyme IDO and the level of the suppressive cytokine transforming growth factor-β (TGF-β) in tissues. CTLA-4 blockade was associated with decreased viral RNA levels in lymph nodes and an increase in the effector function of both SIV-specific CD4+ and CD8+ T cells. Therefore, blunting Treg function in macaques infected with SIV did not have detrimental virologic effects and may provide a valuable approach to complement ART and therapeutic vaccination in the treatment of HIV-1 infection. PMID:16896154

  10. Beta-Adrenergic Blockade Does not Prevent Polycythemia or Decrease in Plasma Volume in Men at 4300 m Altitude

    NASA Technical Reports Server (NTRS)

    Grover, R. F.; Selland, M. A.; McCullough, R. G.; Dahms, T. E.; Wolfel, E. E.; Butterfield, G. E.; Reeves, J. T.; Greenleaf, J. E.

    1998-01-01

    When humans ascend to high altitude (ALT) their plasma volume (PV) and total blood volume (BV) decrease during the first few days. With continued residence over several weeks, the hypoxia-induced stimulation of erythropoietin increases red cell production which tends to restore BV. Because hypoxia also activates the beta-adrenergic system, which stimulates red blood cell production, we investigated the effect of adrenergic beta-receptor inhibition with propranolol on fluid volumes and the polycythemic response in 11 healthy unacclimatized men (21-33 years old exposed to an ALT of 4300 m (barometric pressure 460 Torr) for 3 weeks on Pikes Peak, Colorado. PV was determined by the Evans blue dye method (PV(sub EB)), BV by the carbon monoxide method (BV(sub CO)), red cell volume (RCV)was calculated from hematocrit (Hct) and BV(sub CO), and serum erythropoietin concentration ([EPO]) and reticulocyte count, were also determined. All determinations were made at sea level and after 9-11 (ALT-10) and 9-20 (ALT-20) days at ALT. At sea level and ALT, six men received propranolol (pro, 240 mg/day), and five received a placebo (pla). Effective beta-blockade did not modify the mean (SE) maximal values of [EPO] [pla: 24.9 (3.5) vs pro: 24.5 (1.5) mU/ml] or reticulocyte count [pla: 2.7 (0.7) vs pro: 2.2 (0.5)%]; nor changes in PV(sub EB)[pla: -15.8 (3.8) vs pro: -19.9 (2.8)%], RCV(sub CO) [pla: +7.0 (6.7) vs pro: +10.1 (6.1)%], or BV(sub CO) [pla: -7.3 (2.3) vs pro: -7.1 (3.9)%]. In the absence of weight loss, a redistribution of body water with no net loss is implied. Hence, activation of the beta-adrenergic system did not appear to affect the hypovolemic or polycythemic responses that occurred during 3 weeks at 4300 m ALT in these subjects.

  11. Beta-Adrenergic Blockade Does not Prevent Polycythemia or Decrease in Plasma Volume in Men at 4300 m Altitude

    NASA Technical Reports Server (NTRS)

    Grover, R. F.; Selland, M. A.; McCullough, R. G.; Dahms, T. E.; Wolfel, E. E.; Butterfield, G. E.; Reeves, J. T.; Greenleaf, J. E.

    1998-01-01

    When humans ascend to high altitude (ALT) their plasma volume (PV) and total blood volume (BV) decrease during the first few days. With continued residence over several weeks, the hypoxia-induced stimulation of erythropoietin increases red cell production which tends to restore BV. Because hypoxia also activates the beta-adrenergic system, which stimulates red blood cell production, we investigated the effect of adrenergic beta-receptor inhibition with propranolol on fluid volumes and the polycythemic response in 11 healthy unacclimatized men (21-33 years old exposed to an ALT of 4300 m (barometric pressure 460 Torr) for 3 weeks on Pikes Peak, Colorado. PV was determined by the Evans blue dye method (PV(sub EB)), BV by the carbon monoxide method (BV(sub CO)), red cell volume (RCV)was calculated from hematocrit (Hct) and BV(sub CO), and serum erythropoietin concentration ([EPO]) and reticulocyte count, were also determined. All determinations were made at sea level and after 9-11 (ALT-10) and 9-20 (ALT-20) days at ALT. At sea level and ALT, six men received propranolol (pro, 240 mg/day), and five received a placebo (pla). Effective beta-blockade did not modify the mean (SE) maximal values of [EPO] [pla: 24.9 (3.5) vs pro: 24.5 (1.5) mU/ml] or reticulocyte count [pla: 2.7 (0.7) vs pro: 2.2 (0.5)%]; nor changes in PV(sub EB)[pla: -15.8 (3.8) vs pro: -19.9 (2.8)%], RCV(sub CO) [pla: +7.0 (6.7) vs pro: +10.1 (6.1)%], or BV(sub CO) [pla: -7.3 (2.3) vs pro: -7.1 (3.9)%]. In the absence of weight loss, a redistribution of body water with no net loss is implied. Hence, activation of the beta-adrenergic system did not appear to affect the hypovolemic or polycythemic responses that occurred during 3 weeks at 4300 m ALT in these subjects.

  12. Blockade of the N-Methyl-D-Aspartate Glutamate Receptor Ameliorates Lipopolysaccharide-Induced Renal Insufficiency

    PubMed Central

    Huang, Ho-Shiang; Ma, Ming-Chieh

    2015-01-01

    N-methyl-D-aspartate (NMDA) receptor activation in rat kidney reduces renal perfusion and ultrafiltration. Hypoperfusion-induced ischemia is the most frequent cause of functional insufficiency in the endotoxemic kidney. Here, we used non-hypotensive rat model of lipopolysaccharide-induced endotoxemia to examine whether NMDA receptor hyperfunction contributes to acute kidney injury. Lipopolysaccharide-induced renal damage via increased enzymuria and hemodynamic impairments were ameliorated by co-treatment with the NMDA receptor blocker, MK-801. The NMDA receptor NR1 subunit in the rat kidney mainly co-localized with serine racemase, an enzyme responsible for synthesizing the NMDA receptor co-agonist, D-serine. The NMDA receptor hyperfunction in lipopolysaccharide-treated kidneys was demonstrated by NR1 and serine racemase upregulation, particularly in renal tubules, and by increased D-serine levels. Lipopolysaccharide also induced cell damage in cultured tubular cell lines and primary rat proximal tubular cells. This damage was mitigated by MK-801 and by small interfering RNA targeting NR1. Lipopolysaccharide increased cytokine release in tubular cell lines via toll-like receptor 4. The release of interleukin-1β from these cells are the most abundant. An interleukin-1 receptor antagonist not only attenuated cell death but also abolished lipopolysaccharide-induced NR1 and serine racemase upregulation and increases in D-serine secretion, suggesting that interleukin-1β-mediated NMDA receptor hyperfunction participates in lipopolysaccharide-induced tubular damage. The results of this study indicate NMDA receptor hyperfunction via cytokine effect participates in lipopolysaccharide-induced renal insufficiency. Blockade of NMDA receptors may represent a promising therapeutic strategy for the treatment of sepsis-associated renal failure. PMID:26133372

  13. Blockade of lysophosphatidic acid receptors LPAR1/3 ameliorates lung fibrosis induced by irradiation

    SciTech Connect

    Gan, Lu; Xue, Jian-Xin; Li, Xin; Liu, De-Song; Ge, Yan; Ni, Pei-Yan; Deng, Lin; Lu, You; Jiang, Wei

    2011-05-27

    Highlights: {yields} Lysophosphatidic acid (LPA) levels and its receptors LPAR1/3 transcripts were elevated during the development of radiation-induced lung fibrosis. {yields} Lung fibrosis was obviously alleviated in mice treated with the dual LPAR1/3 antagonist, VPC12249. {yields} VPC12249 administration effectively inhibited radiation-induced fibroblast accumulation in vivo, and suppressed LPA-induced fibroblast proliferation in vitro. {yields} LPA-LPAR1/3 signaling regulated TGF{beta}1 and CTGF expressions in radiation-challenged lungs, but only influenced CTGF expression in cultured fibroblasts. {yields} LPA-LPAR1/3 signaling induced fibroblast proliferation through a CTGF-dependent pathway, rather than through TGF{beta}1 activation. -- Abstract: Lung fibrosis is a common and serious complication of radiation therapy for lung cancer, for which there are no efficient treatments. Emerging evidence indicates that lysophosphatidic acid (LPA) and its receptors (LPARs) are involved in the pathogenesis of fibrosis. Here, we reported that thoracic radiation with 16 Gy in mice induced development of radiation lung fibrosis (RLF) accompanied by obvious increases in LPA release and LPAR1 and LPAR3 (LPAR1/3) transcripts. RLF was significantly alleviated in mice treated with the dual LPAR1/3 antagonist, VPC12249. VPC12249 administration effectively prolonged animal survival, restored lung structure, inhibited fibroblast accumulation and reduced collagen deposition. Moreover, profibrotic cytokines in radiation-challenged lungs obviously decreased following administration of VPC12249, including transforming growth factor {beta}1 (TGF{beta}1) and connective tissue growth factor (CTGF). In vitro, LPA induced both fibroblast proliferation and CTGF expression in a dose-dependent manner, and both were suppressed by blockade of LPAR1/3. The pro-proliferative activity of LPA on fibroblasts was inhibited by siRNA directed against CTGF. Together, our data suggest that the LPA-LPAR1

  14. Add-on angiotensin II receptor blockade lowers urinary transforming growth factor-beta levels.

    PubMed

    Agarwal, Rajiv; Siva, Senthuran; Dunn, Stephen R; Sharma, Kumar

    2002-03-01

    TGF-beta1 that improved over 1 month of add-on therapy with losartan. We speculate that dual blockade with losartan and an ACE inhibitor may provide additional renoprotection by decreasing renal production of TGF-beta1.

  15. Selective blockade of the orexin-2 receptor attenuates ethanol self-administration, place preference, and reinstatement.

    PubMed

    Shoblock, James R; Welty, Natalie; Aluisio, Leah; Fraser, Ian; Motley, S Timothy; Morton, Kirsten; Palmer, James; Bonaventure, Pascal; Carruthers, Nicholas I; Lovenberg, Timothy W; Boggs, Jamin; Galici, Ruggero

    2011-05-01

    Orexin-1 receptor antagonists have been shown to block the reinforcing effects of drugs of abuse and food. However, whether blockade of orexin-2 receptor has similar effects has not been determined. We have recently described the in vitro and in vivo effects of JNJ-10397049, a selective and brain penetrant orexin-2 receptor antagonist. The goal of these studies was to evaluate whether systemic administration of JNJ-10397049 blocks the rewarding effects of ethanol and reverses ethanol withdrawal in rodents. As a comparison, SB-408124, a selective orexin-1 receptor antagonist, was also evaluated. Rats were trained to orally self-administer ethanol (8% v/v) or saccharin (0.1% v/v) under a fixed-ratio 3 schedule of reinforcement. A separate group of rats received a liquid diet of ethanol (8% v/v) and withdrawal signs were evaluated 4 h after ethanol discontinuation. In addition, ethanol-induced increases in extracellular dopamine levels in the nucleus accumbens were tested. In separate experiments, the acquisition, expression, and reinstatement of conditioned place preference (CPP) were evaluated in mice. Our results indicate that JNJ-10397049 (1, 3, and 10 mg/kg, sc) dose-dependently reduced ethanol self-administration without changing saccharin self-administration, dopamine levels, or withdrawal signs in rats. Treatment with JNJ-10397049 (10 mg/kg, sc) attenuated the acquisition, expression, and reinstatement of ethanol CPP and ethanol-induced hyperactivity in mice. Surprisingly, SB-408124 (3, 10 and 30 mg/kg, sc) did not have any effect in these procedures. Collectively, these results indicate, for the first time, that blockade of orexin-2 receptors is effective in reducing the reinforcing effects of ethanol.

  16. Selective endothelin B receptor blockade does not influence BNP-induced natriuresis in man.

    PubMed

    van der Zander, K; Houben, A J H M; Webb, D J; Udo, E; Kietselaer, B; Hofstra, L; De Mey, J G R; de Leeuw, P W

    2006-03-01

    Brain natriuretic peptide (BNP) and endothelin-1 (ET-1) both exhibit natriuretic activity within the human kidney. Furthermore, they both act partly through activation of the endothelial nitric oxide pathway. Since ET-1 may cause vasodilation and natriuresis via stimulation of the ET-B receptor, the aim of the present study was to investigate whether renal ET-B receptors participate in the renal actions of BNP. In this placebo-controlled, crossover study, we infused BNP (4 pmol/kg/min) or placebo (i.v.) for 1 h, with or without co-infusion of the ET-B receptor antagonist BQ-788 (50 nmol/min) for 15 min on 4 separate days, in 10 healthy subjects (mean age 54+/-6 years.). During infusion, we measured effective renal plasma flow (ERPF), and glomerular filtration rate (GFR) using PAH/inulin clearance. Cardiac output was measured before and after infusion, using echocardiography. Blood pressure and heart rate (HR) were monitored as well. Urine and plasma samples were taken every hour to measure diuresis, natriuresis, cyclic 3',5' guanosine monophosphate, and ET-1 levels. BNP with or without ET-B receptor blockade increased natriuresis and diuresis. In addition, BNP alone increased GFR and filtered load, without changing ERPF. BQ-788 infusion did not affect renal hemodynamics or natriuresis. Neither BNP nor BQ-788 altered cardiac output, blood pressure, and heart rate. In conclusion, the present study shows that selective ET-B receptor blockade has no effect on the BNP-induced natriuresis and glomerular filtration rate.

  17. Angiotensin II receptor blockade limits glomerular injury in rats with reduced renal mass.

    PubMed Central

    Lafayette, R A; Mayer, G; Park, S K; Meyer, T W

    1992-01-01

    The effects of angiotensin II (AII) blockade were compared with the effects of angiotensin converting enzyme inhibition in rats with reduced nephron number. Rats were subjected to five-sixths renal ablation and divided into four groups with similar values for blood pressure and serum creatinine after 2 wk. Group 1 then served as untreated controls, while group 2 received the AII receptor antagonist MK954 (which has previously been designated DuP753), group 3 received the converting enzyme inhibitor enalapril, and group 4 received a combination of reserpine, hydralazine, and hydrochlorothiazide. Micropuncture and morphologic studies were performed 10 wk later. Converting enzyme inhibition, AII receptor blockade, and the combination regimen were equally effective in reversing systemic hypertension (time-averaged systolic blood pressure: group 1, 185 +/- 5 mmHg; group 2, 125 +/- 2 mmHg; group 3, 127 +/- 2 mmHg; group 4, 117 +/- 4 mmHg). Micropuncture studies showed that glomerular transcapillary pressure was reduced significantly by converting enzyme inhibition and by AII blockade but not by the combination regimen (delta P: group 1, 49 +/- 1 mmHg; group 2, 42 +/- 1 mmHg; group 3, 40 +/- 2 mmHg, group 4, 47 +/- 1 mmHg). Reduction of systemic blood pressure was associated with the development of markedly less proteinuria and segmental glomerular sclerosis in rats receiving enalapril and MK954 but not in rats receiving the combination regimen (prevalence of glomerular sclerotic lesions: group 1, 41 +/- 4%; group 2, 9 +/- 1%; group 3, 9 +/- 1%; group 4, 33 +/- 6%). These results indicate that the effects of converting enzyme inhibition on remnant glomerular function and structure depend on reduction in AII activity and are not attributable simply to normalization of systemic blood pressure. PMID:1522231

  18. Enhancement of Adipocyte Browning by Angiotensin II Type 1 Receptor Blockade

    PubMed Central

    Tsukuda, Kana; Mogi, Masaki; Iwanami, Jun; Kanno, Harumi; Nakaoka, Hirotomo; Wang, Xiao-Li; Bai, Hui-Yu; Shan, Bao-Shuai; Kukida, Masayoshi; Higaki, Akinori; Yamauchi, Toshifumi; Min, Li-Juan; Horiuchi, Masatsugu

    2016-01-01

    Browning of white adipose tissue (WAT) has been highlighted as a new possible therapeutic target for obesity, diabetes and lipid metabolic disorders, because WAT browning could increase energy expenditure and reduce adiposity. The new clusters of adipocytes that emerge with WAT browning have been named ‘beige’ or ‘brite’ adipocytes. Recent reports have indicated that the renin-angiotensin system (RAS) plays a role in various aspects of adipose tissue physiology and dysfunction. The biological effects of angiotensin II, a major component of RAS, are mediated by two receptor subtypes, angiotensin II type 1 receptor (AT1R) and type 2 receptor (AT2R). However, the functional roles of angiotensin II receptor subtypes in WAT browning have not been defined. Therefore, we examined whether deletion of angiotensin II receptor subtypes (AT1aR and AT2R) may affect white-to-beige fat conversion in vivo. AT1a receptor knockout (AT1aKO) mice exhibited increased appearance of multilocular lipid droplets and upregulation of thermogenic gene expression in inguinal white adipose tissue (iWAT) compared to wild-type (WT) mice. AT2 receptor-deleted mice did not show miniaturization of lipid droplets or alteration of thermogenic gene expression levels in iWAT. An in vitro experiment using adipose tissue-derived stem cells showed that deletion of the AT1a receptor resulted in suppression of adipocyte differentiation, with reduction in expression of thermogenic genes. These results indicate that deletion of the AT1a receptor might have some effects on the process of browning of WAT and that blockade of the AT1 receptor could be a therapeutic target for the treatment of metabolic disorders. PMID:27992452

  19. Postcontest blockade of dopamine receptors inhibits development of the winner effect in the California mouse (Peromyscus californicus).

    PubMed

    Becker, Elizabeth A; Marler, Catherine A

    2015-04-01

    The winner effect is an accumulation of previous wins that increase future winning. A primary unanswered question about the winner effect is how do individuals integrate information about previous wins? Dopamine (DA) has been implicated because phosphorylated tyrosine hydroxylase (pTH), the rate-limiting enzyme for DA biosynthesis, is elevated following multiple winning experiences. Moreover, DA receptor blockers and agonists influence aggression when administered prior to male-male contests. In the current study, we administered D1- and D2-like DA receptor antagonists immediately after a contest and examined the development of the winner effect in the territorial California mouse, Peromyscus californicus. During a 3-contest training phase, resident males experienced winning contests, followed immediately by a peripheral injection of either a DA receptor antagonist or vehicle or a handling experience (without injection). The DA receptor antagonists used in this study did not influence locomotion. To assess the cumulative effects of previous winning, males were subjected to a final test contest with a more competitive intruder. The winner effect was significantly decreased by both D1- and D2-like receptor antagonists administered during training. During the test contest, attack behavior was significantly reduced by previous administration of both types of DA receptor antagonists compared with controls. D1-like receptor blockade also diminished chasing behavior, whereas D2-antagonist treated animals continued to pursue opponents. During training against a less competitive intruder, there was no difference in aggressive behaviors between experimental and controls males. Our data indicate that DA activity between contests is concomitant with the competitive advantage gained from multiple winning experiences.

  20. Cat carotid body chemoreceptor responses before and after nicotine receptor blockade with alpha-bungarotoxin.

    PubMed

    Mulligan, E; Lahiri, S

    1987-01-01

    The nature of nicotine receptors in the carotid body was studied in anesthetized, paralyzed and artificially ventilated cats. Chemoreceptor discharge in single or few-fiber preparations of the carotid sinus nerve was measured during isocapnic hypoxia, hyperoxic hypercapnia and in response to nicotine injections before and after administration of alpha-bungarotoxin (10 cats) and after alpha-bungarotoxin plus mecamylamine (7 cats) which binds to neuromuscular-type nicotine cholinergic receptors. alpha-Bungarotoxin caused a slight enhancement of the chemoreceptor response to hypoxia without affecting the chemoreceptor stimulation by nicotine. Mecamylamine (1-5 mg, i.v.), a ganglionic-type nicotinic receptor blocker, had no further effect on the response to hypoxia while it completely abolished the chemoreceptor stimulation by nicotine. Thus the nicotinic receptors in the cat carotid body which elicit excitation of chemosensory fibers appear to be of the ganglionic-type. Blockade of neuromuscular and ganglionic types of nicotinic receptors in the carotid body by alpha-bungarotoxin and mecamylamine does not attenuate the chemosensory responses to either hypoxia or hypercapnia. These nicotinic receptors therefore, do not appear to play an essential role in hypoxic or hypercapnic chemoreception in the cat carotid body.

  1. Beta adrenergic blockade decreases the immunomodulatory effects of social disruption stress.

    PubMed

    Hanke, M L; Powell, N D; Stiner, L M; Bailey, M T; Sheridan, J F

    2012-10-01

    During physiological or psychological stress, catecholamines produced by the sympathetic nervous system (SNS) regulate the immune system. Previous studies report that the activation of β-adrenergic receptors (βARs) mediates the actions of catecholamines and increases pro-inflammatory cytokine production in a number of different cell types. The impact of the SNS on the immune modulation of social defeat has not been examined. The following studies were designed to determine whether SNS activation during social disruption stress (SDR) influences anxiety-like behavior as well as the activation, priming, and glucocorticoid resistance of splenocytes after social stress. CD-1 mice were exposed to one, three, or six cycles of SDR and HPLC analysis of the plasma and spleen revealed an increase in catecholamines. After six cycles of SDR the open field test was used to measure behaviors characteristic of anxiety and indicated that the social defeat induced increase in anxiety-like behavior was blocked by pre-treatment with the β-adrenergic antagonist propranolol. Pre-treatment with the β-adrenergic antagonist propranolol did not significantly alter corticosterone levels indicating no difference in activation of the hypothalamic-pituitary-adrenal axis. In addition to anxiety-like behavior the SDR induced splenomegaly and increase in plasma IL-6, TNFα, and MCP-1 were each reversed by pre-treatment with propranolol. Furthermore, flow cytometric analysis of cells from propranolol pretreated mice reduced the SDR-induced increase in the percentage of CD11b(+) splenic macrophages and significantly decreased the expression of TLR2, TLR4, and CD86 on the surface of these cells. In addition, supernatants from 18h LPS-stimulated ex vivo cultures of splenocytes from propranolol-treated SDR mice contained less IL-6. Likewise propranolol pre-treatment abrogated the glucocorticoid insensitivity of CD11b(+) cells ex vivo when compared to splenocytes from SDR vehicle-treated mice

  2. Differential effects of dopamine and opioid receptor blockade on motivated Coca-Cola drinking behavior and associated changes in brain, skin and muscle temperatures.

    PubMed

    Kiyatkin, E A

    2010-05-05

    Although pharmacological blockade of both dopamine (DA) and opiate receptors has an inhibiting effect on appetitive motivated behaviors, it is still unclear which physiological mechanisms affected by these treatments underlie the behavioral deficit. To clarify this issue, we examined how pharmacological blockade of either DA (SCH23390+eticlopride at 0.2 mg/kg each) or opioid receptors (naloxone 1 mg/kg) affects motor activity and temperature fluctuations in the nucleus accumbens (NAcc), temporal muscle, and facial skin associated with motivated Coca-Cola drinking behavior in rats. In drug-free conditions, presentation of a cup containing 5 ml of Coca-Cola induced locomotor activation and rapid NAcc temperature increases, which both transiently decreased during drinking, and phasically increased again after the cup was emptied. Muscle temperatures followed this pattern, but increases were weaker and more delayed than those in the NAcc. Skin temperature rapidly dropped after cup presentation, remained at low levels during consumption, and slowly restored during post-consumption behavioral activation. By itself, DA receptor blockade induced robust decrease in spontaneous locomotion, moderate increases in brain and muscle temperatures, and a relative increase in skin temperatures, suggesting metabolic activation coupled with adynamia. Following this treatment (approximately 180 min), motor activation to cup presentation and Coca-Cola consumption were absent, but rats showed NAcc and muscle temperature increases following cup presentation comparable to control. Therefore, DA receptor blockade does not affect significantly central and peripheral autonomic responses to appetitive stimuli, but eliminates their behavior-activating effects, thus disrupting appetitive behavior and blocking consumption. Naloxone alone slightly decreased brain and muscle temperatures and increased skin temperatures, pointing at the enhanced heat loss and possible minor inhibition of basal

  3. Differential effects of dopamine and opioid receptor blockade on motivated Coca-Cola drinking behavior and associated changes in brain, skin and muscle temperatures

    PubMed Central

    Kiyatkin, Eugene A.

    2010-01-01

    Although pharmacological blockade of both dopamine (DA) and opiate receptors has an inhibiting effect on appetitive motivated behaviors, it is still unclear which physiological mechanisms affected by these treatments underlie the behavioral deficit. To clarify this issue, we examined how pharmacological blockade of either DA (SCH23390 + eticlopride at 0.2 mg/kg each) or opioid receptors (naloxone 1 mg/kg) affects motor activity and temperature fluctuations in the nucleus acumens (NAcc), temporal muscle, and facial skin associated with motivated Coca-Cola drinking behavior in rats. In drug-free conditions, presentation of a cup containing 5 ml of Coca-Cola induced locomotor activation and rapid NAcc temperature increases, which both transiently decreased during drinking, and phasically increased again after the cup was emptied. Muscle temperatures followed this pattern, but increases were weaker and more delayed than those in the NAcc. Skin temperature rapidly dropped after cup presentation, remained at low levels during consumption, and slowly restored during post-consumption behavioral activation. By itself, DA receptor blockade induced robust decrease in spontaneous locomotion, moderate increases in brain and muscle temperatures, and a relative increase in skin temperatures, suggesting metabolic activation coupled with adynamia. Following this treatment (∼180 min), motor activation to cup presentation and Coca-Cola consumption were absent, but rats showed NAcc and muscle temperature increases following cup presentation comparable to control. Therefore, DA receptor blockade does not affect significantly central and peripheral autonomic responses to appetitive stimuli, but eliminates their behavior-activating effects, thus disrupting appetitive behavior and blocking consumption. Naloxone alone slightly decreased brain and muscle temperatures and increased skin temperatures, pointing at the enhanced heat loss and possible minor inhibition of basal metabolic

  4. Ozone-induced hyperresponsiveness and blockade of M2 muscarinic receptors by eosinophil major basic protein.

    PubMed

    Yost, B L; Gleich, G J; Fryer, A D

    1999-10-01

    Control of airway smooth muscle is provided by parasympathetic nerves that release acetylcholine onto M(3) muscarinic receptors. Acetylcholine release is limited by inhibitory M(2) muscarinic receptors. In antigen-challenged guinea pigs, hyperresponsiveness is due to blockade of neuronal M(2) receptors by eosinophil major basic protein (MBP). Because exposure of guinea pigs to ozone also causes M(2) dysfunction and airway hyperresponsiveness, the role of eosinophils in ozone-induced hyperresponsiveness was tested. Animals were exposed to filtered air or to 2 parts/million ozone for 4 h. Twenty-four hours later, the muscarinic agonist pilocarpine no longer inhibited vagally induced bronchoconstriction in ozone-exposed animals, indicating M(2) dysfunction. M(2) receptor function in ozone-exposed animals was protected by depletion of eosinophils with antibody to interleukin-5 and by pretreatment with antibody to guinea pig MBP. M(2) function was acutely restored by removal of MBP with heparin. Ozone-induced hyperreactivity was also prevented by antibody to MBP and was reversed by heparin. These data show that loss of neuronal M(2) receptor function after ozone is due to release of eosinophil MBP.

  5. Initial evidence that GLP-1 receptor blockade fails to suppress postprandial satiety or promote food intake in humans.

    PubMed

    Melhorn, Susan J; Tyagi, Vidhi; Smeraglio, Anne; Roth, Christian L; Schur, Ellen A

    2014-11-01

    Glucagon-like peptide 1 (GLP-1) has incretin effects that are well-documented, but the independent role of GLP-1 action in human satiety perception is debated. We hypothesized that blockade of GLP-1 receptors would suppress postprandial satiety and increase voluntary food intake. After an overnight fast, eight normal weight participants (seven men, BMI 19-24.7 kg/m(2), age 19-29 year) were enrolled in a double-blind, placebo-controlled, randomized crossover study of the GLP-1 antagonist Exendin-[9-39] (Ex-9) to determine if the satiating effects of a meal are dependent on GLP-1 signaling in humans. Following a fasting blood draw, iv infusion of Ex-9 (600-750 pmol/kg/min) or saline began. Thirty minutes later, subjects consumed a standardized breakfast followed 90 min later (at the predicted time of maximal endogenous circulating GLP-1) by an ad libitum buffet meal to objectively measure satiety. Infusions ended once the buffet meal was complete. Visual analog scale ratings of hunger and fullness and serial assessments of plasma glucose, insulin, and GLP-1 concentrations were done throughout the experiment. Contrary to the hypothesis, during Ex-9 infusion subjects reported a greater decrease in hunger due to consumption of the breakfast (Ex-9 -62 ± 5; placebo -41 ± 9; P=0.01) than during placebo. There were no differences in ad libitum caloric intake between Ex-9 and placebo. Ex-9 increased glucose, insulin, and endogenous GLP-1, which may have counteracted any effects of Ex-9 infusion to block satiety signaling. Blockade of GLP-1 receptors failed to suppress subjective satiety following a standardized meal or increase voluntary food intake in healthy, normal-weight subjects.

  6. Angiotensin 2 type 1 receptor blockade different affects postishemic kidney injury in normotensive and hypertensive rats.

    PubMed

    Miloradović, Zoran; Ivanov, Milan; Jovović, Đurđica; Karanović, Danijela; Vajić, Una Jovana; Marković-Lipkovski, Jasmina; Mihailović-Stanojević, Nevena; Milanović, Jelica Grujić

    2016-12-01

    Many studies demonstrated that angiotensin 2 type 1 receptor (AT1R) blockade accelerates renal recovery in post-ischaemic kidney but there are many controversies related to its net effect on kidney structure and function. During the past years, our research group was trying to define the pathophysiological significance of the renin-angiotensin system on post-ischemic acute renal failure (ARF) development in normotensive Wistar as well as hypertensive rats (SHR). This review mostly summarizes our experience in that field. Our previous studies in normotensive rats revealed that AT1R blockade, except slightly renal vascular resistance improvement, had no other obvious beneficial effects, and therefore implies angiotensin 2 (Ang-2) overexpression as non-dominant on kidney reperfusion injuries development. Similarly it was observed in Wistar rats with induced mild (L-NAME, 3 mg/kg b.w.) nitric oxide (NO) deficiency. Expectably, in strong induced (L-NAME, 10 mg/kg b.w.) NO deficiency associated with ARF, massive tubular injuries indicate harmful effects of AT1R blockade, implying strongly disturbed glomerular filtration and suggesting special precaution related to AT1R blockers usage. Opposite to previous, by our opinion, AT1R antagonism promises new advance in treatment of essentially hypertensive subjects who develop ARF. Increased glomerular filtration, diminished oxidative stress, and most importantly improved tubular structure in postishemic SHR treated with AT1R blocker losartan, implicate Ang-2 over production as potently agent in the kidney ischemic injury, partly trough generation of reactive oxygen species. These data contribute understanding the pathogenesis of this devastating illness in hypertensive surroundings.

  7. Localized β-adrenergic receptor blockade does not affect sweating during exercise.

    PubMed

    Buono, Michael J; Tabor, Brian; White, Ailish

    2011-05-01

    The purpose of the current study was to determine the effect of a locally administered nonselective β-adrenergic antagonist on sweat gland function during exercise. Systemically administered propranolol has been reported to increase, decrease, or not alter sweat production during exercise. To eliminate the confounding systemic effects associated with orally administered propranolol, we used iontophoresis to deliver it to the eccrine sweat glands within a localized area on one forearm prior to exercise. This allowed for determination of the direct effect of β-adrenergic receptor blockade on sweating during exercise. Subjects (n = 14) reported to the laboratory (23 ± 1°C, 35 ± 3% relative humidity) after having refrained from exercise for ≥12 h. Propranolol (1% solution) was administered to a 5-cm(2) area of the flexor surface of one forearm via iontophoresis (1.5 mA) for 5 min. A saline solution was administered to the opposing arm via iontophoresis. Each subject then exercised on a motor-driven treadmill at 75% of their age-predicted maximal heart rate for 20 min, while sweat rate was measured simultaneously in both forearms. Immediately after cessation of exercise, the number of active sweat glands was measured by application of iodine-impregnated paper to each forearm. The sweat rate for the control and propranolol-treated forearm was 0.62 ± 41 and 0.60 ± 0.44 (SD) mg·cm(-2)·min(-1), respectively (P = 0.86). The density of active sweat glands for the control and propranolol-treated forearm was 130 ± 6 and 134 ± 5 (SD) glands/cm(2), respectively, (P = 0.33). End-exercise skin temperature was 32.9 ± 0.2 and 33.1 ± 0.3°C for the control and propranolol-treated forearm, respectively (P = 0.51). Results of the current study show that when propranolol is administered locally, thus eliminating the potential confounding systemic effects of the drug, it does not directly affect sweating during the initial stages of high-intensity exercise in young, healthy

  8. Pharmacological Blockade of 5-HT7 Receptors as a Putative Fast Acting Antidepressant Strategy

    PubMed Central

    Mnie-Filali, Ouissame; Faure, Céline; Lambás-Señas, Laura; Mansari, Mostafa El; Belblidia, Hassina; Gondard, Elise; Etiévant, Adeline; Scarna, Hélène; Didier, Anne; Berod, Anne; Blier, Pierre; Haddjeri, Nasser

    2011-01-01

    Current antidepressants still display unsatisfactory efficacy and a delayed onset of therapeutic action. Here we show that the pharmacological blockade of serotonin 7 (5-HT7) receptors produced a faster antidepressant-like response than the commonly prescribed antidepressant fluoxetine. In the rat, the selective 5-HT7 receptor antagonist SB-269970 counteracted the anxiogenic-like effect of fluoxetine in the open field and exerted an antidepressant-like effect in the forced swim test. In vivo, 5-HT7 receptors negatively regulate the firing activity of dorsal raphe 5-HT neurons and become desensitized after long-term administration of fluoxetine. In contrast with fluoxetine, a 1-week treatment with SB-269970 did not alter 5-HT firing activity but desensitized cell body 5-HT autoreceptors, enhanced the hippocampal cell proliferation, and counteracted the depressive-like behavior in olfactory bulbectomized rats. Finally, unlike fluoxetine, early-life administration of SB-269970, did not induce anxious/depressive-like behaviors in adulthood. Together, these findings indicate that the 5-HT7 receptor antagonists may represent a new class of antidepressants with faster therapeutic action. PMID:21326194

  9. A2B adenosine receptor blockade enhances macrophage-mediated bacterial phagocytosis and improves polymicrobial sepsis survival in mice.

    PubMed

    Belikoff, Bryan G; Hatfield, Stephen; Georgiev, Peter; Ohta, Akio; Lukashev, Dmitriy; Buras, Jon A; Remick, Daniel G; Sitkovsky, Michail

    2011-02-15

    Antimicrobial treatment strategies must improve to reduce the high mortality rates in septic patients. In noninfectious models of acute inflammation, activation of A2B adenosine receptors (A2BR) in extracellular adenosine-rich microenvironments causes immunosuppression. We examined A2BR in antibacterial responses in the cecal ligation and puncture (CLP) model of sepsis. Antagonism of A2BR significantly increased survival, enhanced bacterial phagocytosis, and decreased IL-6 and MIP-2 (a CXC chemokine) levels after CLP in outbred (ICR/CD-1) mice. During the CLP-induced septic response in A2BR knockout mice, hemodynamic parameters were improved compared with wild-type mice in addition to better survival and decreased plasma IL-6 levels. A2BR deficiency resulted in a dramatic 4-log reduction in peritoneal bacteria. The mechanism of these improvements was due to enhanced macrophage phagocytic activity without augmenting neutrophil phagocytosis of bacteria. Following ex vivo LPS stimulation, septic macrophages from A2BR knockout mice had increased IL-6 and TNF-α secretion compared with wild-type mice. A therapeutic intervention with A2BR blockade was studied by using a plasma biomarker to direct therapy to those mice predicted to die. Pharmacological blockade of A2BR even 32 h after the onset of sepsis increased survival by 65% in those mice predicted to die. Thus, even the late treatment with an A2BR antagonist significantly improved survival of mice (ICR/CD-1) that were otherwise determined to die according to plasma IL-6 levels. Our findings of enhanced bacterial clearance and host survival suggest that antagonism of A2BRs offers a therapeutic target to improve macrophage function in a late treatment protocol that improves sepsis survival.

  10. D-1 and D-2 receptor blockade have additive cataleptic effects in mice, but receptor effects may interact in opposite ways.

    PubMed

    Klemm, W R; Block, H

    1988-02-01

    The dopaminergic role of D-1 and D-2 receptors in catalepsy was evaluated using drugs with preferential receptor affinities. The D-1 antagonist, SCH 23390, caused distinct catalepsy in mice at 1, 2, and 10 mg/kg, IP, but not at two lower doses. The selective D-1 blocker, molindone, also caused catalepsy at 5 and 10 mg/kg; and blockade of both receptor types produced additive cataleptogenic effects. Apomorphine (4 mg/kg), which is an agonist for both receptors, potentiated SCH 23390-induced catalepsy much more than it did the catalepsy induced by molindone; the potentiation was produced by higher, not lower, doses of apomorphine. To determine if the apomorphine potentiation was mediated by D-1 or D-2 receptors, we tested selective agonists in mice that were concurrently injected with selective blockers. SCH 23390-induced catalepsy was potentiated by a large dose of the D-2 agonist, bromocriptine. The catalepsy of D-2 blockade with molindone was not potentiated by the D-1 agonist, SKF 38393, which slightly disrupted the catalepsy of D-2 blockade. We conclude that catalepsy is not a simple D-2 blockade phenomenon and that preferential antagonism of either receptor type can cause catalepsy. Catalepsy is most profound when both receptor types are blocked. Dopamine agonists, in large concentrations, are known to promote movements, and thus it is not surprising that they tend to disrupt catalepsy.(ABSTRACT TRUNCATED AT 250 WORDS)

  11. Blockade of Cocaine or σ Receptor Agonist Self Administration by Subtype-Selective σ Receptor Antagonists.

    PubMed

    Katz, Jonathan L; Hiranita, Takato; Kopajtic, Theresa A; Rice, Kenner C; Mesangeau, Christophe; Narayanan, Sanju; Abdelazeem, Ahmed H; McCurdy, Christopher R

    2016-07-01

    The identification of sigma receptor (σR) subtypes has been based on radioligand binding and, despite progress with σ1R cellular function, less is known about σR subtype functions in vivo. Recent findings that cocaine self administration experience will trigger σR agonist self administration was used in this study to assess the in vivo receptor subtype specificity of the agonists (+)-pentazocine, PRE-084 [2-(4-morpholinethyl) 1-phenylcyclohexanecarboxylate hydrochloride], and 1,3-di-o-tolylguanidine (DTG) and several novel putative σR antagonists. Radioligand binding studies determined in vitro σR selectivity of the novel compounds, which were subsequently studied for self administration and antagonism of cocaine, (+)-pentazocine, PRE-084, or DTG self administration. Across the dose ranges studied, none of the novel compounds were self administered, nor did they alter cocaine self administration. All compounds blocked DTG self administration, with a subset also blocking (+)-pentazocine and PRE-084 self administration. The most selective of the compounds in binding σ1Rs blocked cocaine self administration when combined with a dopamine transport inhibitor, either methylphenidate or nomifensine. These drug combinations did not decrease rates of responding maintained by food reinforcement. In contrast, the most selective of the compounds in binding σ2Rs had no effect on cocaine self administration in combination with either dopamine transport inhibitor. Thus, these results identify subtype-specific in vivo antagonists, and the utility of σR agonist substitution for cocaine self administration as an assay capable of distinguishing σR subtype selectivity in vivo. These results further suggest that effectiveness of dual σR antagonism and dopamine transport inhibition in blocking cocaine self administration is specific for σ1Rs and further support this dual targeting approach to development of cocaine antagonists. U.S. Government work not protected by U

  12. Blockade of Cocaine or σ Receptor Agonist Self Administration by Subtype-Selective σ Receptor Antagonists

    PubMed Central

    Hiranita, Takato; Kopajtic, Theresa A.; Rice, Kenner C.; Mesangeau, Christophe; Narayanan, Sanju; Abdelazeem, Ahmed H.; McCurdy, Christopher R.

    2016-01-01

    The identification of sigma receptor (σR) subtypes has been based on radioligand binding and, despite progress with σ1R cellular function, less is known about σR subtype functions in vivo. Recent findings that cocaine self administration experience will trigger σR agonist self administration was used in this study to assess the in vivo receptor subtype specificity of the agonists (+)-pentazocine, PRE-084 [2-(4-morpholinethyl) 1-phenylcyclohexanecarboxylate hydrochloride], and 1,3-di-o-tolylguanidine (DTG) and several novel putative σR antagonists. Radioligand binding studies determined in vitro σR selectivity of the novel compounds, which were subsequently studied for self administration and antagonism of cocaine, (+)-pentazocine, PRE-084, or DTG self administration. Across the dose ranges studied, none of the novel compounds were self administered, nor did they alter cocaine self administration. All compounds blocked DTG self administration, with a subset also blocking (+)-pentazocine and PRE-084 self administration. The most selective of the compounds in binding σ1Rs blocked cocaine self administration when combined with a dopamine transport inhibitor, either methylphenidate or nomifensine. These drug combinations did not decrease rates of responding maintained by food reinforcement. In contrast, the most selective of the compounds in binding σ2Rs had no effect on cocaine self administration in combination with either dopamine transport inhibitor. Thus, these results identify subtype-specific in vivo antagonists, and the utility of σR agonist substitution for cocaine self administration as an assay capable of distinguishing σR subtype selectivity in vivo. These results further suggest that effectiveness of dual σR antagonism and dopamine transport inhibition in blocking cocaine self administration is specific for σ1Rs and further support this dual targeting approach to development of cocaine antagonists. PMID:27189970

  13. Atrophy of submandibular gland by the duct ligation and a blockade of SP receptor in rats.

    PubMed

    Hishida, Sumiyo; Ozaki, Noriyuki; Honda, Takashi; Shigetomi, Toshio; Ueda, Minoru; Hibi, Hideharu; Sugiura, Yasuo

    2016-05-01

    To clarify the mechanisms underlying the submandibular gland atrophies associated with ptyalolithiasis, morphological changes were examined in the rat submandibular gland following either surgical intervention of the duct or functional blockade at substance P receptors (SPRs). Progressive acinar atrophy was observed after duct ligation or avulsion of periductal tissues. This suggested that damage to periductal tissue involving nerve fibers might contribute to ligation-associated acinar atrophy. Immunohistochemically labeled-substance P positive nerve fibers (SPFs) coursed in parallel with the main duct and were distributed around the interlobular, striated, granular and intercalated duct, and glandular acini. Strong SPR immunoreactivity was observed in the duct. Injection into the submandibular gland of a SPR antagonist induced marked acinar atrophy. The results revealed that disturbance of SPFs and SPRs might be involved in the atrophy of the submandibular gland associated with ptyalolithiasis.

  14. Atrophy of submandibular gland by the duct ligation and a blockade of SP receptor in rats

    PubMed Central

    Hishida, Sumiyo; Ozaki, Noriyuki; Honda, Takashi; Shigetomi, Toshio; Ueda, Minoru; Hibi, Hideharu; Sugiura, Yasuo

    2016-01-01

    ABSTRACT To clarify the mechanisms underlying the submandibular gland atrophies associated with ptyalolithiasis, morphological changes were examined in the rat submandibular gland following either surgical intervention of the duct or functional blockade at substance P receptors (SPRs). Progressive acinar atrophy was observed after duct ligation or avulsion of periductal tissues. This suggested that damage to periductal tissue involving nerve fibers might contribute to ligation-associated acinar atrophy. Immunohistochemically labeled-substance P positive nerve fibers (SPFs) coursed in parallel with the main duct and were distributed around the interlobular, striated, granular and intercalated duct, and glandular acini. Strong SPR immunoreactivity was observed in the duct. Injection into the submandibular gland of a SPR antagonist induced marked acinar atrophy. The results revealed that disturbance of SPFs and SPRs might be involved in the atrophy of the submandibular gland associated with ptyalolithiasis. PMID:27303108

  15. Effects of acute and chronic beta-receptor blockade on ventricular repolarisation in man.

    PubMed Central

    Edvardsson, N; Olsson, S B

    1981-01-01

    The right ventricular repolarisation phase was studied electrophysiologically after an injection of 15 mg metoprolol in 16 healthy volunteers. Eight of them were restudied after chronic treatment with 400 mg metoprolol daily for five weeks. The assessment of the repolarisation time included ventricular effective refractory periods, monophasic action potential duration, and the QT interval measured during atrial stimulation at different driving frequencies. The acute administration of 15 mg metoprolol intravenously had no detectable effect on the repolarisation phase, while chronic treatment caused a significant increase of the ventricular effective refractory periods, monophasic action potential duration, and the QT interval during atrial stimulation. Thus the study confirmed the contrasting effect of acute and chronic beta-receptor blockade on the ventricular repolarisation time in man. PMID:7259913

  16. Angiotensin receptor blockade mediated amelioration of mucopolysaccharidosis type I cardiac and craniofacial pathology

    PubMed Central

    Webber, Beau R.; McElmurry, Ronald T.; Rudser, Kyle D.; DeFeo, Anthony P.; Muradian, Michael; Petryk, Anna; Hallgrimsson, Benedikt; Blazar, Bruce R.; Tolar, Jakub

    2017-01-01

    Mucopolysaccharidosis type I (MPS IH) is a lysosomal storage disease (LSD) caused by inactivating mutations to the alpha-L-iduronidase (IDUA) gene. Treatment focuses on IDUA enzyme replacement and currently employed methods can be non-uniform in their efficacy particularly for the cardiac and craniofacial pathology. Therefore, we undertook efforts to better define the pathological cascade accounting for treatment refractory manifestations and demonstrate a role for the renin angiotensin system (RAS) using the IDUA−/− mouse model. Perturbation of the RAS in the aorta was more profound in male animals suggesting a causative role in the observed gender dimorphism and angiotensin receptor blockade (ARB) resulted in improved cardiac function. Further, we show the ability of losartan to prevent shortening of the snout, a common craniofacial anomaly in IDUA−/− mice. These data show a key role for the RAS in MPS associated pathology and support the inclusion of losartan as an augmentation to current therapies. PMID:27743312

  17. Alpha 2-adrenergic receptor turnover in adipose tissue and kidney: irreversible blockade of alpha 2-adrenergic receptors by benextramine

    SciTech Connect

    Taouis, M.; Berlan, M.; Lafontan, M.

    1987-01-01

    The recovery of post- and extrasynaptic alpha 2-adrenergic receptor-binding sites was studied in vivo in male golden hamsters after treatment with an irreversible alpha-adrenoceptor antagonist benextramine, a tetramine disulfide that possesses a high affinity for alpha 2-binding sites. The kidney alpha 2-adrenergic receptor number was measured with (/sup 3/H)yohimbine, whereas (/sup 3/H)clonidine was used for fat cell and brain membrane alpha 2-binding site identification. Benextramine treatment of fat cell, kidney, and brain membranes reduced or completely suppressed, in an irreversible manner, (/sup 3/H) clonidine and (/sup 3/H)yohimbine binding without modifying adenosine (A1-receptor) and beta-adrenergic receptor sites. This irreversible binding was also found 1 and 2 hr after intraperitoneal administration of benextramine to the hamsters. Although it bound irreversibly to peripheral and central alpha 2-adrenergic receptors on isolated membranes, benextramine was unable to cross the blood-brain barrier of the hamster at the concentrations used (10-20 mg/kg). After the irreversible blockade, alpha 2-binding sites reappeared in kidney and adipose tissue following a monoexponential time course. Recovery of binding sites was more rapid in kidney than in adipose tissue; the half-lives of the receptor were 31 and 46 hr, respectively in the tissues. The rates of receptor production were 1.5 and 1.8 fmol/mg of protein/hr in kidney and adipose tissue. Reappearance of alpha 2-binding sites was associated with a rapid recovery of function (antilipolytic potencies of alpha 2-agonists) in fat cells inasmuch as occupancy of 15% of (/sup 3/H)clonidine-binding sites was sufficient to promote 40% inhibition of lipolysis. Benextramine is a useful tool to estimate turnover of alpha 2-adrenergic receptors under normal and pathological situations.

  18. Mineralocorticoid receptor blockade prevents stress-induced modulation of multiple memory systems in the human brain.

    PubMed

    Schwabe, Lars; Tegenthoff, Martin; Höffken, Oliver; Wolf, Oliver T

    2013-12-01

    Accumulating evidence suggests that stress may orchestrate the engagement of multiple memory systems in the brain. In particular, stress is thought to favor dorsal striatum-dependent procedural over hippocampus-dependent declarative memory. However, the neuroendocrine mechanisms underlying these modulatory effects of stress remain elusive, especially in humans. Here, we targeted the role of the mineralocorticoid receptor (MR) in the stress-induced modulation of dorsal striatal and hippocampal memory systems in the human brain using a combination of event-related functional magnetic resonance imaging and pharmacologic blockade of the MR. Eighty healthy participants received the MR antagonist spironolactone (300 mg) or a placebo and underwent a stressor or control manipulation before they performed, in the scanner, a classification task that can be supported by the hippocampus and the dorsal striatum. Stress after placebo did not affect learning performance but reduced explicit task knowledge and led to a relative increase in the use of more procedural learning strategies. At the neural level, stress promoted striatum-based learning at the expense of hippocampus-based learning. Functional connectivity analyses showed that this shift was associated with altered coupling of the amygdala with the hippocampus and dorsal striatum. Mineralocorticoid receptor blockade before stress prevented the stress-induced shift toward dorsal striatal procedural learning, same as the stress-induced alterations of amygdala connectivity with hippocampus and dorsal striatum, but resulted in significantly impaired performance. Our findings indicate that the stress-induced shift from hippocampal to dorsal striatal memory systems is mediated by the amygdala, required to preserve performance after stress, and dependent on the MR. © 2013 Society of Biological Psychiatry.

  19. GRK2 blockade with βARKct is essential for cardiac β2-adrenergic receptor signaling towards increased contractility

    PubMed Central

    2013-01-01

    Background β1- and β2–adrenergic receptors (ARs) play distinct roles in the heart, e.g. β1AR is pro-contractile and pro-apoptotic but β2AR anti-apoptotic and only weakly pro-contractile. G protein coupled receptor kinase (GRK)-2 desensitizes and opposes βAR pro-contractile signaling by phosphorylating the receptor and inducing beta-arrestin (βarr) binding. We posited herein that GRK2 blockade might enhance the pro-contractile signaling of the β2AR subtype in the heart. We tested the effects of cardiac-targeted GRK2 inhibition in vivo exclusively on β2AR signaling under normal conditions and in heart failure (HF). Results We crossed β1AR knockout (B1KO) mice with cardiac-specific transgenic mice expressing the βARKct, a known GRK2 inhibitor, and studied the offspring under normal conditions and in post-myocardial infarction (MI). βARKct expression in vivo proved essential for β2AR-dependent contractile function, as β2AR stimulation with isoproterenol fails to increase contractility in either healthy or post-MI B1KO mice and it only does so in the presence of βARKct. The main underlying mechanism for this is blockade of the interaction of phosphodiesterase (PDE) type 4D with the cardiac β2AR, which is normally mediated by the actions of GRK2 and βarrs on the receptor. The molecular “brake” that PDE4D poses on β2AR signaling to contractility stimulation is thus “released”. Regarding the other beneficial functions of cardiac β2AR, βARKct increased overall survival of the post-MI B1KO mice progressing to HF, via a decrease in cardiac apoptosis and an increase in wound healing-associated inflammation early (at 24 hrs) post-MI. However, these effects disappear by 4 weeks post-MI, and, in their place, upregulation of the other major GRK in the heart, GRK5, is observed. Conclusions GRK2 inhibition in vivo with βARKct is absolutely essential for cardiac β2AR pro-contractile signaling and function. In addition, β2AR anti-apoptotic signaling in

  20. GRK2 blockade with βARKct is essential for cardiac β2-adrenergic receptor signaling towards increased contractility.

    PubMed

    Salazar, Norma C; Vallejos, Ximena; Siryk, Ashley; Rengo, Giuseppe; Cannavo, Alessandro; Liccardo, Daniela; De Lucia, Claudio; Gao, Erhe; Leosco, Dario; Koch, Walter J; Lymperopoulos, Anastasios

    2013-08-28

    β1- and β2-adrenergic receptors (ARs) play distinct roles in the heart, e.g. β1AR is pro-contractile and pro-apoptotic but β2AR anti-apoptotic and only weakly pro-contractile. G protein coupled receptor kinase (GRK)-2 desensitizes and opposes βAR pro-contractile signaling by phosphorylating the receptor and inducing beta-arrestin (βarr) binding. We posited herein that GRK2 blockade might enhance the pro-contractile signaling of the β2AR subtype in the heart. We tested the effects of cardiac-targeted GRK2 inhibition in vivo exclusively on β2AR signaling under normal conditions and in heart failure (HF). We crossed β1AR knockout (B1KO) mice with cardiac-specific transgenic mice expressing the βARKct, a known GRK2 inhibitor, and studied the offspring under normal conditions and in post-myocardial infarction (MI). βARKct expression in vivo proved essential for β2AR-dependent contractile function, as β2AR stimulation with isoproterenol fails to increase contractility in either healthy or post-MI B1KO mice and it only does so in the presence of βARKct. The main underlying mechanism for this is blockade of the interaction of phosphodiesterase (PDE) type 4D with the cardiac β2AR, which is normally mediated by the actions of GRK2 and βarrs on the receptor. The molecular "brake" that PDE4D poses on β2AR signaling to contractility stimulation is thus "released". Regarding the other beneficial functions of cardiac β2AR, βARKct increased overall survival of the post-MI B1KO mice progressing to HF, via a decrease in cardiac apoptosis and an increase in wound healing-associated inflammation early (at 24 hrs) post-MI. However, these effects disappear by 4 weeks post-MI, and, in their place, upregulation of the other major GRK in the heart, GRK5, is observed. GRK2 inhibition in vivo with βARKct is absolutely essential for cardiac β2AR pro-contractile signaling and function. In addition, β2AR anti-apoptotic signaling in post-MI HF is augmented by

  1. The non-competitive blockade of GABAA receptors by an aqueous extract of water hemlock (Cicuta douglasii) tubers.

    PubMed

    Green, Benedict T; Goulart, Camila; Welch, Kevin D; Pfister, James A; McCollum, Isabelle; Gardner, Dale R

    2015-12-15

    Water hemlocks (Cicuta spp.) are acutely toxic members of the Umbellierae family; the toxicity is due to the presence of C17-polyacetylenes such as cicutoxin. There is only limited evidence of noncompetitive antagonism by C17-polyacetylenes at GABAA receptors. In this work with WSS-1 cells, we documented the noncompetitive blockade of GABAA receptors by an aqueous extract of water hemlock (Cicuta douglasii) and modulated the actions of the extract with a pretreatment of 10 μM midazolam.

  2. Anticancer immunotherapy by CTLA-4 blockade: obligatory contribution of IL-2 receptors and negative prognostic impact of soluble CD25

    PubMed Central

    Hannani, Dalil; Vétizou, Marie; Enot, David; Rusakiewicz, Sylvie; Chaput, Nathalie; Klatzmann, David; Desbois, Melanie; Jacquelot, Nicolas; Vimond, Nadège; Chouaib, Salem; Mateus, Christine; Allison, James P; Ribas, Antoni; Wolchok, Jedd D; Yuan, Jianda; Wong, Philip; Postow, Michael; Mackiewicz, Andrzej; Mackiewicz, Jacek; Schadendorff, Dirk; Jaeger, Dirk; Korman, Alan J; Bahjat, Keith; Maio, Michele; Calabro, Luana; Teng, Michele WL; Smyth, Mark J; Eggermont, Alexander; Robert, Caroline; Kroemer, Guido; Zitvogel, Laurence

    2015-01-01

    The cytotoxic T lymphocyte antigen-4 (CTLA-4)-blocking antibody ipilimumab induces immune-mediated long-term control of metastatic melanoma in a fraction of patients. Although ipilimumab undoubtedly exerts its therapeutic effects via immunostimulation, thus far clinically useful, immunologically relevant biomarkers that predict treatment efficiency have been elusive. Here, we show that neutralization of IL-2 or blocking the α and β subunits of the IL-2 receptor (CD25 and CD122, respectively) abolished the antitumor effects and the accompanying improvement of the ratio of intratumoral T effector versus regulatory cells (Tregs), which were otherwise induced by CTLA-4 blockade in preclinical mouse models. CTLA-4 blockade led to the reduction of a suppressive CD4+ T cell subset expressing Lag3, ICOS, IL-10 and Egr2 with a concomitant rise in IL-2-producing effector cells that lost FoxP3 expression and accumulated in regressing tumors. While recombinant IL-2 improved the therapeutic efficacy of CTLA-4 blockade, the decoy IL-2 receptor α (IL-2Rα, sCD25) inhibited the anticancer effects of CTLA-4 blockade. In 262 metastatic melanoma patients receiving ipilimumab, baseline serum concentrations of sCD25 represented an independent indicator of overall survival, with high levels predicting resistance to therapy. Altogether, these results unravel a role for IL-2 and IL-2 receptors in the anticancer activity of CTLA-4 blockade. Importantly, our study provides the first immunologically relevant biomarker, namely elevated serum sCD25, that predicts resistance to CTLA-4 blockade in patients with melanoma. PMID:25582080

  3. Blockade of P2X7 receptors or pannexin-1 channels similarly attenuates postischemic damage

    PubMed Central

    Cisneros-Mejorado, Abraham; Gottlieb, Miroslav; Cavaliere, Fabio; Magnus, Tim; Koch-Nolte, Friederich; Scemes, Eliana; Pérez-Samartín, Alberto; Matute, Carlos

    2015-01-01

    The role of P2X7 receptors and pannexin-1 channels in ischemic damage remains controversial. Here, we analyzed their contribution to postanoxic depolarization after ischemia in cultured neurons and in brain slices. We observed that pharmacological blockade of P2X7 receptors or pannexin-1 channels delayed the onset of postanoxic currents and reduced their slope, and that simultaneous inhibition did not further enhance the effects of blocking either one. These results were confirmed in acute cortical slices from P2X7 and pannexin-1 knockout mice. Oxygen-glucose deprivation in cortical organotypic cultures caused neuronal death that was reduced with P2X7 and pannexin-1 blockers as well as in organotypic cultures derived from mice lacking P2X7 and pannexin 1. Subsequently, we used transient middle cerebral artery occlusion to monitor the neuroprotective effect of those drugs in vivo. We found that P2X7 and pannexin-1 antagonists, and their ablation in knockout mice, substantially attenuated the motor symptoms and reduced the infarct volume to ~50% of that in vehicle-treated or wild-type animals. These results show that P2X7 receptors and pannexin-1 channels are major mediators of postanoxic depolarization in neurons and of brain damage after ischemia, and that they operate in the same deleterious signaling cascade leading to neuronal and tissue demise. PMID:25605289

  4. BLOCKADE OF PGE2, PGD2 RECEPTORS CONFERS PROTECTION AGAINST PREPATENT SCHISTOSOMIASIS MANSONI IN MICE.

    PubMed

    Abdel-Ghany, Rasha; Rabia, Ibrahim; El-Ahwany, Eman; Saber, Sameh; Gamal, Rasha; Nagy, Faten; Mahmoud, Olaa; Hamad, Rabab Salem; Barakat, Walled

    2015-12-01

    Schistosomiasis is a chronic disease with considerable social impact. Despite the availability of affordable chemotherapy, drug treatment has not significantly reduced the overall number of disease cases. Among other mechanisms, the parasite produces PGE2 and PGD2 to evade host immune defenses. To investigate the role of PGE2 and PGD2 in schistosomiasis, we evaluated the effects of L-161,982, Ah6809 (PGE2 receptor antagonists alone of combined with each other) and MK-0524 (PGD2 receptor antagonist) during prepatent Schistosoma mansoni infection. Drugs were administered intraperitoneally an hour before and 24 hours after infection of C57BL/6 mice with 100 Schistosoma mansoni cercariae. L-161,982, Ah6809, their combination and MK-0524 caused partial protection against pre-patent S. mansoni infection which was mediated by biasing the immune response towards Th1 phenotype. These results showed that blockade of PGE2 and PGD2 receptors confers partial protection against pre-patent S. mansoni infection in mice and that they may be useful as adjunctive therapy to current anti-schistosomal drugs or vaccines.

  5. Blockade of P2X7 receptors or pannexin-1 channels similarly attenuates postischemic damage.

    PubMed

    Cisneros-Mejorado, Abraham; Gottlieb, Miroslav; Cavaliere, Fabio; Magnus, Tim; Koch-Nolte, Friederich; Scemes, Eliana; Pérez-Samartín, Alberto; Matute, Carlos

    2015-05-01

    The role of P2X7 receptors and pannexin-1 channels in ischemic damage remains controversial. Here, we analyzed their contribution to postanoxic depolarization after ischemia in cultured neurons and in brain slices. We observed that pharmacological blockade of P2X7 receptors or pannexin-1 channels delayed the onset of postanoxic currents and reduced their slope, and that simultaneous inhibition did not further enhance the effects of blocking either one. These results were confirmed in acute cortical slices from P2X7 and pannexin-1 knockout mice. Oxygen-glucose deprivation in cortical organotypic cultures caused neuronal death that was reduced with P2X7 and pannexin-1 blockers as well as in organotypic cultures derived from mice lacking P2X7 and pannexin 1. Subsequently, we used transient middle cerebral artery occlusion to monitor the neuroprotective effect of those drugs in vivo. We found that P2X7 and pannexin-1 antagonists, and their ablation in knockout mice, substantially attenuated the motor symptoms and reduced the infarct volume to ~50% of that in vehicle-treated or wild-type animals. These results show that P2X7 receptors and pannexin-1 channels are major mediators of postanoxic depolarization in neurons and of brain damage after ischemia, and that they operate in the same deleterious signaling cascade leading to neuronal and tissue demise.

  6. Inhibition of drinking in water-deprived rats by combined central angiotensin II and cholinergic receptor blockade.

    PubMed

    Hoffman, W E; Ganten, U; Phillips, M I; Schmid, P G; Schelling, P; Ganten, D

    1978-01-01

    The effect of blockade of central angiotensin II (AII) receptors and cholinergic receptors on thirst induced by water deprivation was studied in Sprague-Dawley rats and rats with hereditary hypothalamic diabetes insipidus (DI). Neither central AII nor cholinergic blockade alone affected drinking. Antagonism of both receptors simultaneously, however, significantly inhibited water intake of both Sprague-Dawley and DI rats. This inhibitory effect was not observed in water-deprived, nephrectomized rats. The combined antagonism on water intake was specific, since milk intake in hungry rats was not affected by simultaneous AII and cholinergic blockade. Isorenin concentrations in brain tissue were at control levels in water-deprived, nephrectomized, and non-nephrectomized Sprague-Dawley rats but were increased in water-deprived DI rats. The results suggest that angiotensin and cholinergic receptors in the brain have a physiological role in thirst. Thirst is maintained when either receptor is intact, but reduced when both receptors are inhibited by antagonists. They are independently capable of maintaining thirst.

  7. Effect of cholecystokinin-2 receptor blockade on rat stomach ECL cells. A histochemical, electron-microscopic and chemical study.

    PubMed

    Chen, D; Zhao, C M; Norlén, P; Björkqvist, M; Ding, X Q; Kitano, M; Håkanson, R

    2000-01-01

    The ECL cells in the oxyntic mucosa of rat stomach produce histamine and chromogranin A-derived peptides such as pancreastatin. The cells respond to gastrin via cholecystokinin-2 (CCK2) receptors. A CCK2 receptor blockade was induced by treatment (for up to 8 weeks) with two receptor antagonists, YM022 and YF476. Changes in ECL-cell morphology were examined by immunocytochemistry and electron microscopy, while changes in ECL cell-related biochemical parameters were monitored by measuring serum pancreastatin and oxyntic mucosal pancreastatin, and histamine concentrations, and histidine decarboxylase (HDC) activity. The CCK2 receptor blockade reduced the ECL-cell density only marginally, if at all, but transformed the ECL cells from slender, elongated cells with prominent projections to small, spherical cells without projections. The Golgi complex and the rough endoplasmic reticulum were diminished. Secretory vesicles were greatly reduced in volume density in the trans Golgi area. Circulating pancreastatin concentration and oxyntic mucosal HDC activity were lowered within a few hours. Oxyntic mucosal histamine and pancreastatin concentrations were reduced only gradually. The CCK2 receptor blockade was found to prevent the effects of omeprazole-evoked hypergastrinaemia on the ECL-cell activity and density. In conclusion, gastrin, acting on CCK2 receptors, is needed to maintain the shape, size and activity of the ECL cells, but not for maintaining the ECL-cell population.

  8. Dual Endothelin Receptor Blockade Abrogates Right Ventricular Remodeling and Biventricular Fibrosis in Isolated Elevated Right Ventricular Afterload

    PubMed Central

    Nielsen, Eva Amalie; Sun, Mei; Honjo, Osami; Hjortdal, Vibeke E.; Redington, Andrew N.; Friedberg, Mark K.

    2016-01-01

    Background Pulmonary arterial hypertension is usually fatal due to right ventricular failure and is frequently associated with co-existing left ventricular dysfunction. Endothelin-1 is a powerful pro-fibrotic mediator and vasoconstrictor that is elevated in pulmonary arterial hypertension. Endothelin receptor blockers are commonly used as pulmonary vasodilators, however their effect on biventricular injury, remodeling and function, despite elevated isolated right ventricular afterload is unknown. Methods Elevated right ventricular afterload was induced by progressive pulmonary artery banding. Seven rabbits underwent pulmonary artery banding without macitentan; 13 received pulmonary artery banding + macitentan; and 5 did not undergo inflation of the pulmonary artery band (sham-operated controls). Results: Right and left ventricular collagen content was increased with pulmonary artery banding compared to sham-operated controls and ameliorated by macitentan. Right ventricular fibrosis signaling (connective tissue growth factor and endothelin-1 protein levels); extra-cellular matrix remodeling (matrix-metalloproteinases 2 and 9), apoptosis and apoptosis-related peptides (caspases 3 and 8) were increased with pulmonary artery banding compared with sham-operated controls and decreased with macitentan. Conclusion Isolated right ventricular afterload causes biventricular fibrosis, right ventricular apoptosis and extra cellular matrix remodeling, mediated by up-regulation of endothelin-1 and connective tissue growth factor signaling. These pathological changes are ameliorated by dual endothelin receptor blockade despite persistent elevated right ventricular afterload. PMID:26765263

  9. Blockade of nociceptin/orphanin FQ receptor signaling reverses LPS-induced depressive-like behavior in mice.

    PubMed

    Medeiros, Iris U; Ruzza, Chiara; Asth, Laila; Guerrini, Remo; Romão, Pedro R T; Gavioli, Elaine C; Calo, Girolamo

    2015-10-01

    Nociceptin/orphanin FQ is the natural ligand of a Gi-protein coupled receptor named NOP. This peptidergic system is involved in the regulation of mood states and inflammatory responses. The present study aimed to investigate the consequences of blocking NOP signaling in lipopolysaccharide (LPS)-induced sickness and depressive-like behaviors in mice. LPS 0.8mg/kg, ip, significantly induced sickness signs such as weight loss, decrease of water and food intake and depressive-like behavior in the tail suspension test. Nortriptyline (ip, 60min prior the test) reversed the LPS-induced depressive states. The NOP receptor antagonist SB-612111, 30min prior LPS, did not modify LPS-induced sickness signs and depressive-like behavior. However, when injected 24h after LPS, NOP antagonists (UFP-101, icv, and SB-612111, ip) significantly reversed the mood effects of LPS. LPS evoked similar sickness signs and significantly increased tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) plasma levels 6h post-injection in wild-type ((NOP(+/+)) and NOP knockout ((NOP(-/-)) mice. However, LPS treatment elicited depressive-like effects in NOP(+/+) but not in NOP(-/-) mice. In conclusion, the pharmacological and genetic blockade of NOP signaling does not affect LPS evoked sickness signs while reversing depressive-like behavior. Copyright © 2015 Elsevier Inc. All rights reserved.

  10. TNF-alpha blockade by a dimeric TNF type I receptor molecule selectively inhibits adaptive immune responses.

    PubMed

    Colagiovanni, D B; Suniga, M A; Frazier, J L; Edwards, C K; Fleshner, M; McCay, J A; White, K L; Shopp, G M

    2000-11-01

    Tumor necrosis factor-alpha (TNF-alpha) is a mediator of severe inflammatory processes, including rheumatoid arthritis. Suppression of TNF with a soluble type I or type II receptor molecule (TNF-RI or TNF-RII) has the potential to decrease cytokine levels and modulate inflammatory diseases in humans. However, it has recently been reported that treatment of mice with a TNF-RI:Fc immunoadhesin protein augmented Gram positive infections and subsequent mortality. To determine if TNF-alpha blockade with soluble TNF-alpha receptors might alter immune system function, assays were assessed in rodents treated with a dimeric form of the p55 TNF-RI, Tumor Necrosis Factor-binding protein (TNFbp). Administration of TNFbp resulted in suppression of primary and secondary IgG antibody responses and cell-mediated immune function. No treatment-related differences were detected in immune-enhancing assays or non-specific immune function parameters. Bacterial host resistance assays with Listeria monocytogenes, Staphylococcus aureus or Escherichia coli showed an increase in tissue colony counts only with L. monocytogenes challenged animals following TNFbp administration. These results suggest that TNFbp has the capacity to inhibit adaptive immune function in experimental animal models. Studies suggest that while reducing TNF-alpha is important in controlling cytokine-dependent disease states, maintenance of a threshold level may be critical for normal immune function.

  11. Effects of epidermal growth factor receptor blockade on ependymoma stem cells in vitro and in orthotopic mouse models.

    PubMed

    Servidei, Tiziana; Meco, Daniela; Trivieri, Nadia; Patriarca, Valentina; Vellone, Valerio Gaetano; Zannoni, Gian Franco; Lamorte, Giuseppe; Pallini, Roberto; Riccardi, Riccardo

    2012-09-01

    Some lines of evidence suggest that tumors, including ependymoma, might arise from a subpopulation of cells, termed cancer stem cells (CSCs), with self-renewal and tumor-initiation properties. Given the strict dependence of CSCs on epidermal growth factor (EGF) through EGF receptor (EGFR), we investigated the effects of EGFR inhibitors in ependymoma-stem cells (SCs) in vitro and in orthotopic mouse models. We established two ependymoma-SC lines from two recurrent pediatric ependymoma. Both lines expressed markers of radial glia--the candidate SCs of ependymoma--and showed renewal ability, multipotency, and tumorigenicity after orthotopic implantation, despite markedly different expression of CD133 (94 vs. 6%). High phosphorylated-EGFR/EGFR ratio was detected, which decreased after differentiation. EGFR inhibitors (gefitinib and AEE788) reduced clonogenicity, proliferation and survival of ependymoma-SC lines dose-dependently, and blocked EGF-induced activation of EGFR, Akt and extracellular signal-regulated kinase 1/2. Overall, AEE788 was more effective than gefitinib. EGFR blockade as well as differentiation strongly reduced CD133 expression. However, ex vivo treatment with AEE788 did not impair orthotopic tumor engraftment, whereas ex vivo differentiation did, suggesting that CD133 does not absolutely segregate for tumorigenicity in ependymoma-SCs. Orally administered AEE788 prolonged survival of mice bearing ependymoma-SC-driven orthotopic xenografts from 56 to 63 days, close to statistical significance (log-rank p=0.06). Our study describes for the first time EGFR signaling in ependymoma-SCs and the effects of EGFR blockade in complementary in vitro and in vivo systems. The experimental models we developed can be used to further investigate the activity of EGFR inhibitors or other antineoplastic agents in this tumor.

  12. Inhibition of β2-adrenergic receptor reduces triple-negative breast cancer brain metastases: The potential benefit of perioperative β-blockade.

    PubMed

    Choy, Cecilia; Raytis, John L; Smith, David D; Duenas, Matthew; Neman, Josh; Jandial, Rahul; Lew, Michael W

    2016-06-01

    In response to recent studies, we investigated an association between perioperative β-blockade and breast cancer metastases. First, a retrospective study examining perioperative β-blocker use and cancer recurrence and metastases was conducted on 1,029 patients who underwent breast cancer surgery at the City of Hope Cancer Center between 2000 and 2010. We followed the clinical study and examined proliferation, migration, and invasion in vitro of primary and brain-metastatic breast cancer cells in response to β2-activation and inhibition. We also investigated in vivo the metastatic potential of propranolol-treated metastatic cells. For stage II breast cancer patients, perioperative β-blockade was associated with decreased cancer recurrence using Cox regression analysis (hazard's ratio =0.51; 95% CI: 0.23-0.97; p=0.041). Triple-negative (TN) brain-metastatic cells were found to have increased β2-adrenergic receptor mRNA and protein expression relative to TN primary cells. In response to β2-adrenergic receptor activation, TN brain-metastatic cells also exhibited increased cell proliferation and migration relative to the control. These effects were abrogated by propranolol. Propranolol decreased β2-adrenergic receptor-activated invasion. In vivo, propranolol treatment of TN brain-metastatic cells decreased establishment of brain metastases. Our results suggest that stress and corresponding β2-activation may promote the establishment of brain metastases of TN breast cancer cells. In addition, our data suggest a benefit to perioperative β-blockade during surgery-induced stress with respect to breast cancer recurrence and metastases.

  13. The modified Geller-Seifter test in rats was insensitive to GABAB receptor positive modulation or blockade, or 5-HT1A receptor activation.

    PubMed

    Paterson, Neil E; Hanania, Taleen

    2010-03-17

    Both the GABA(B) receptor positive modulator GS39783 and the GABA(B) receptor antagonist CGP46381 exhibit anxiolytic-like properties in animal models. In the present studies, the effects of GS39783 and CGP46381 in the modified Geller-Seifter task were assessed. First, the predictive validity of the task was confirmed by assessing the effects of multiple anxiolytic and non-anxiolytic compounds on punished and unpunished responding. Rats were trained in the modified Geller-Seifter task. After successful acquisition of the task, chlordiazepoxide, diazepam, MPEP, haloperidol, GS39783, 8-OH-DPAT, alprazolam and CGP46381 were tested consecutively. For each test compound, doses were administered in a randomized, counter-balanced, within-subjects design. Drug tests were performed only when rats exhibited baseline performance (the punished and time-out response rates were less than 10% of the unpunished response rate). Chlordiazepoxide, diazepam, alprazolam and MPEP released punished responding with variable effects on unpunished responding. Haloperidol had a small but significant effect on punished responding at an intermediate dose, and decreased unpunished responding at the highest dose tested. In contrast, administration of the GABA(B) receptor positive modulator GS398783 or the GABA(B) receptor antagonist CGP46381 at doses up to 30 mg/kg had no effects on either punished or unpunished responding. The 5-HT(1A) agonist 8-OH-DPAT did not release punished responding, but significantly decreased unpunished responding at the highest dose tested. The modified Geller-Seifter task generally exhibits good predictive validity for anxiolytic-like compounds. Neither GABA(B) receptor positive allosteric modulation nor blockade exhibited anxiolytic-like properties in the modified Geller-Seifter task. The 5-HT(1A) partial agonist buspirone was similarly ineffective. Copyright 2009 Elsevier B.V. All rights reserved.

  14. Late-onset endothelin-A receptor blockade reduces podocyte injury in homozygous Ren-2 rats despite severe hypertension.

    PubMed

    Opocenský, Martin; Kramer, Herbert J; Bäcker, Angela; Vernerová, Zdenka; Eis, Václav; Cervenka, Ludek; Certíková Chábová, Vera; Tesar, Vladimír; Vanecková, Ivana

    2006-11-01

    We have recently found in male homozygous hypertensive Ren-2 transgenic rats (TGRs) fed a high-salt diet that early onset selective endothelin (ET) A (ET(A)) or nonselective ET(A)/ET B (ET(B)) receptor blockade improved survival rate and reduced proteinuria, glomerulosclerosis, and cardiac hypertrophy, whereas selective ET(A) receptor blockade also significantly attenuated the rise in blood pressure. Because antihypertensive therapy in general is known to be more efficient when started at early age, our study was performed to determine whether onset of ET receptor blockade at a later age in animals with established hypertension will have similar protective effects as does early-onset therapy. Male homozygous TGRs and age-matched normotensive Hannover Sprague-Dawley rats were fed a high-salt diet between days 51 and 90 of age. TGRs received vehicle (untreated), the selective ET(A) receptor blocker atrasentan (ABT-627), or the nonselective ET(A)/ET(B) receptor blocker bosentan. Survival rates in untreated and bosentan-treated TGRs were 50% and 64%, respectively, whereas with atrasentan, survival rate of TGR was 96%, thus, similar to 93% in Hannover Sprague-Dawley rats. From day 60 on, systolic blood pressure in atrasentan-treated TGRs was transiently lower (P<0.05) than in untreated or bosentan-treated TGRs. Glomerular podocyte injury was substantially reduced with atrasentan treatment independent of severe hypertension and strongly correlated with survival (P<0.001). Our data indicate that in homozygous TGR ET receptors play an important role also in established hypertension. Selective ET(A) receptor blockade not only reduces podocyte injury and end-organ damage but also improves growth and survival independently of hypertension.

  15. Reduction of the Morphine Maintenance by Blockade of the NMDA Receptors during Extinction Period in Conditioned Place Preference Paradigm of Rats

    PubMed Central

    Siahposht-Khachaki, Ali; Fatahi, Zahra; Haghparast, Abbas

    2016-01-01

    Introduction: Activation of N-methyl-d-aspartate (NMDA) glutamate receptors in the nucleus accumbens is a component of drug-induced reward mechanism. In addition, NMDA receptors play a major role in brain reward system and activation of these receptors can change firing pattern of dopamine neurons. Blockade of glutamatergic neurotransmission reduces the expression of conditioned place preference (CPP) induced by morphine. Therefore, in this study, by using an NMDA receptor antagonist, DL-2-Amino-5-phosphonopentanoic acid sodium salt (AP5), the role of NMDA receptors on the maintenance and reinstatement of morphine-CPP was investigated. Methods: Forty-three adult male albino Wistar rats were used in this study. After subcutaneous administration of effective dose of morphine (5 mg/kg) during CPP paradigm, the animals received intracerebroventricular doses of AP5(1, 5, and 25 mM/5μL saline) during extinction period (free morphine stage). Conditioning score was recorded during extinction period and reinstatement phase. Besides, another group of the animals received a single dose administration of AP5(5 mM) just before the administration of ineffective dose of morphine (1 mg/kg) in reinstatement phase. Results: The results revealed that two doses of this antagonist (5 and 25 mM) significantly shortened the extinction period of morphine-CPP but did not reduce reinstatement induced by priming dose of morphine. Moreover, the single dose administration of AP5(5 mM) just before prime-morphine injection decreased reinstatement of morphine-CPP. Conclusion: These findings indicate that blockade of NMDA receptors during extinction period reduces maintenance but not reinstatement of morphine. In addition, blocking these receptors in reinstatement phase decreases reinstatement to extinguished morphine. PMID:27872695

  16. Repeated administration of vanilloid receptor TRPV1 antagonists attenuates hyperthermia elicited by TRPV1 blockade.

    PubMed

    Gavva, Narender R; Bannon, Anthony W; Hovland, David N; Lehto, Sonya G; Klionsky, Lana; Surapaneni, Sekhar; Immke, David C; Henley, Charles; Arik, Leyla; Bak, Annette; Davis, James; Ernst, Nadia; Hever, Gal; Kuang, Rongzhen; Shi, Licheng; Tamir, Rami; Wang, Jue; Wang, Weiya; Zajic, Gary; Zhu, Dawn; Norman, Mark H; Louis, Jean-Claude; Magal, Ella; Treanor, James J S

    2007-10-01

    Capsaicin, the active ingredient in some pain-relieving creams, is an agonist of a nonselective cation channel known as the transient receptor potential vanilloid type 1 (TRPV1). The pain-relieving mechanism of capsaicin includes desensitization of the channel, suggesting that TRPV1 antagonism may be a viable pain therapy approach. In agreement with the above notion, several TRPV1 antagonists have been reported to act as antihyperalgesics. Here, we report the in vitro and in vivo characterization of a novel and selective TRPV1 antagonist, N-(4-[6-(4-trifluoromethyl-phenyl)-pyrimidin-4-yloxy]-benzothiazol-2-yl)-acetamide I (AMG 517), and compare its pharmacology with that of a closely related analog, tert-butyl-2-(6-([2-(acetylamino)-1,3-benzothiazol-4-yl]oxy)pyrimidin-4-yl)-5-(trifluoromethyl)phenylcarbamate (AMG8163). Both AMG 517 and AMG8163 potently and completely antagonized capsaicin, proton, and heat activation of TRPV1 in vitro and blocked capsaicin-induced flinch in rats in vivo. To support initial clinical investigations, AMG 517 was evaluated in a comprehensive panel of toxicology studies that included in vivo assessments in rodents, dogs, and monkeys. The toxicology studies indicated that AMG 517 was generally well tolerated; however, transient increases in body temperature (hyperthermia) were observed in all species after AMG 517 dosing. To further investigate this effect, we tested and showed that the antipyretic, acetaminophen, suppressed the hyperthermia caused by TRPV1 blockade. We also showed that repeated administration of TRPV1 antagonists attenuated the hyperthermia response, whereas the efficacy in capsaicin-induced flinch model was maintained. In conclusion, these studies suggest that the transient hyperthermia elicited by TRPV1 blockade may be manageable in the development of TRPV1 antagonists as therapeutic agents. However, the impact of TRPV1 antagonist-induced hyperthermia on their clinical utility is still unknown.

  17. Vasotocin receptor blockade disrupts maternal care of offspring in a viviparous snake, Sistrurus miliarius

    PubMed Central

    Birky, Nikolette K.; Porth, Anita M.; Farrell, Terence M.

    2017-01-01

    ABSTRACT Parental care is a complex social behavior that is widespread among vertebrates. The neuroendocrine regulation of parent-offspring social behavior has been well-described in mammals, and to a lesser extent, in birds and fish. However, little is known regarding the underlying mechanisms that mediate the expression of care behaviors in squamate reptiles. In mammalian model species and humans, posterior pituitary hormones of the oxytocin and vasopressin families mediate parental care behaviors. To test the hypothesis that the regulatory role of posterior pituitary neuropeptides is conserved in a viviparous squamate reptile, we pharmacologically blocked the vasotocin receptor in post-parturient pigmy rattlesnakes, Sistrurus miliarius, and monitored the spatial relationship between mothers and offspring relative to controls. Mothers in the control group demonstrated spatial aggregation with offspring, with mothers having greater post-parturient energy stores aggregating more closely with their offspring. Blockade of vasotocin receptors eliminated evidence of spatial aggregation between mothers and offspring and eliminated the relationship between maternal energetic status and spatial aggregation. Our results are the first to implicate posterior pituitary neuropeptides in the regulation of maternal behavior in a squamate reptile and are consistent with the hypothesis that the neuroendocrine mechanisms underlying social behaviors are broadly conserved among vertebrates. PMID:28069591

  18. Blockade of neuronal dopamine D2 receptor attenuates morphine tolerance in mice spinal cord

    PubMed Central

    Dai, Wen-Ling; Xiong, Feng; Yan, Bing; Cao, Zheng-Yu; Liu, Wen-Tao; Liu, Ji-Hua; Yu, Bo-Yang

    2016-01-01

    Tolerance induced by morphine remains a major unresolved problem and significantly limits its clinical use. Recent evidences have indicated that dopamine D2 receptor (D2DR) is likely to be involved in morphine-induced antinociceptive tolerance. However, its exact effect and molecular mechanism remain unknown. In this study we examined the effect of D2DR on morphine antinociceptive tolerance in mice spinal cord. Chronic morphine treatment significantly increased levels of D2DR in mice spinal dorsal horn. And the immunoreactivity of D2DR was newly expressed in neurons rather than astrocytes or microglia both in vivo and in vitro. Blockade of D2DR with its antagonist (sulpiride and L-741,626, i.t.) attenuated morphine antinociceptive tolerance without affecting basal pain perception. Sulpiride (i.t.) also down-regulated the expression of phosphorylation of NR1, PKC, MAPKs and suppressed the activation of astrocytes and microglia induced by chronic morphine administration. Particularly, D2DR was found to interact with μ opioid receptor (MOR) in neurons, and chronic morphine treatment enhanced the MOR/D2DR interactions. Sulpiride (i.t.) could disrupt the MOR/D2DR interactions and attenuate morphine tolerance, indicating that neuronal D2DR in the spinal cord may be involved in morphine tolerance possibly by interacting with MOR. These results may present new opportunities for the treatment and management of morphine-induced antinociceptive tolerance which often observed in clinic. PMID:28004735

  19. Co-receptor and co-stimulation blockade for mixed chimerism and tolerance without myelosuppressive conditioning

    PubMed Central

    Graca, Luis; Daley, Stephen; Fairchild, Paul J; Cobbold, Stephen P; Waldmann, Herman

    2006-01-01

    Background A major challenge in the application of marrow transplantation as a route to immunological tolerance of a transplanted organ is to achieve hematopoietic stem cell (HSC) engraftment with minimal myelosuppressive treatments. Results We here describe a combined antibody protocol which can achieve long-term engraftment with clinically relevant doses of MHC-mismatched bone marrow, without the need for myelosuppressive drugs. Although not universally applicable in all strains, we achieved reliable engraftment in permissive strains with a two-stage strategy: involving first, treatment with anti-CD8 and anti-CD4 in advance of transplantation; and second, treatment with antibodies targeting CD4, CD8 and CD40L (CD154) at the time of marrow transplantation. Long-term mixed chimerism through co-receptor and co-stimulation blockade facilitated tolerance to donor-type skin grafts, without any evidence of donor-antigen driven regulatory T cells. Conclusion We conclude that antibodies targeting co-receptor and co-stimulatory molecules synergise to enable mixed hematopoietic chimerism and central tolerance, showing that neither cytoreductive conditioning nor 'megadoses' of donor bone marrow are required for donor HSC to engraft in permissive strains. PMID:16638128

  20. The Effect of Opioid Receptor Blockade on the Neural Processing of Thermal Stimuli

    PubMed Central

    Schoell, Eszter D.; Bingel, Ulrike; Eippert, Falk; Yacubian, Juliana; Christiansen, Kerrin; Andresen, Hilke; May, Arne; Buechel, Christian

    2010-01-01

    The endogenous opioid system represents one of the principal systems in the modulation of pain. This has been demonstrated in studies of placebo analgesia and stress-induced analgesia, where anti-nociceptive activity triggered by pain itself or by cognitive states is blocked by opioid antagonists. The aim of this study was to characterize the effect of opioid receptor blockade on the physiological processing of painful thermal stimulation in the absence of cognitive manipulation. We therefore measured BOLD (blood oxygen level dependent) signal responses and intensity ratings to non-painful and painful thermal stimuli in a double-blind, cross-over design using the opioid receptor antagonist naloxone. On the behavioral level, we observed an increase in intensity ratings under naloxone due mainly to a difference in the non-painful stimuli. On the neural level, painful thermal stimulation was associated with a negative BOLD signal within the pregenual anterior cingulate cortex, and this deactivation was abolished by naloxone. PMID:20811582

  1. Vasotocin receptor blockade disrupts maternal care of offspring in a viviparous snake, Sistrurus miliarius.

    PubMed

    Lind, Craig M; Birky, Nikolette K; Porth, Anita M; Farrell, Terence M

    2017-02-15

    Parental care is a complex social behavior that is widespread among vertebrates. The neuroendocrine regulation of parent-offspring social behavior has been well-described in mammals, and to a lesser extent, in birds and fish. However, little is known regarding the underlying mechanisms that mediate the expression of care behaviors in squamate reptiles. In mammalian model species and humans, posterior pituitary hormones of the oxytocin and vasopressin families mediate parental care behaviors. To test the hypothesis that the regulatory role of posterior pituitary neuropeptides is conserved in a viviparous squamate reptile, we pharmacologically blocked the vasotocin receptor in post-parturient pigmy rattlesnakes, Sistrurus miliarius, and monitored the spatial relationship between mothers and offspring relative to controls. Mothers in the control group demonstrated spatial aggregation with offspring, with mothers having greater post-parturient energy stores aggregating more closely with their offspring. Blockade of vasotocin receptors eliminated evidence of spatial aggregation between mothers and offspring and eliminated the relationship between maternal energetic status and spatial aggregation. Our results are the first to implicate posterior pituitary neuropeptides in the regulation of maternal behavior in a squamate reptile and are consistent with the hypothesis that the neuroendocrine mechanisms underlying social behaviors are broadly conserved among vertebrates.

  2. Angiotensin receptor blockade attenuates cigarette smoke-induced lung injury and rescues lung architecture in mice.

    PubMed

    Podowski, Megan; Calvi, Carla; Metzger, Shana; Misono, Kaori; Poonyagariyagorn, Hataya; Lopez-Mercado, Armando; Ku, Therese; Lauer, Thomas; McGrath-Morrow, Sharon; Berger, Alan; Cheadle, Christopher; Tuder, Rubin; Dietz, Harry C; Mitzner, Wayne; Wise, Robert; Neptune, Enid

    2012-01-01

    Chronic obstructive pulmonary disease (COPD) is a prevalent smoking-related disease for which no disease-altering therapies currently exist. As dysregulated TGF-β signaling associates with lung pathology in patients with COPD and in animal models of lung injury induced by chronic exposure to cigarette smoke (CS), we postulated that inhibiting TGF-β signaling would protect against CS-induced lung injury. We first confirmed that TGF-β signaling was induced in the lungs of mice chronically exposed to CS as well as in COPD patient samples. Importantly, key pathological features of smoking-associated lung disease in patients, e.g., alveolar injury with overt emphysema and airway epithelial hyperplasia with fibrosis, accompanied CS-induced alveolar cell apoptosis caused by enhanced TGF-β signaling in CS-exposed mice. Systemic administration of a TGF-β-specific neutralizing antibody normalized TGF-β signaling and alveolar cell death, conferring improved lung architecture and lung mechanics in CS-exposed mice. Use of losartan, an angiotensin receptor type 1 blocker used widely in the clinic and known to antagonize TGF-β signaling, also improved oxidative stress, inflammation, metalloprotease activation and elastin remodeling. These data support our hypothesis that inhibition of TGF-β signaling through angiotensin receptor blockade can attenuate CS-induced lung injury in an established murine model. More importantly, our findings provide a preclinical platform for the development of other TGF-β-targeted therapies for patients with COPD.

  3. Angiotensin receptor blockade attenuates cigarette smoke–induced lung injury and rescues lung architecture in mice

    PubMed Central

    Podowski, Megan; Calvi, Carla; Metzger, Shana; Misono, Kaori; Poonyagariyagorn, Hataya; Lopez-Mercado, Armando; Ku, Therese; Lauer, Thomas; McGrath-Morrow, Sharon; Berger, Alan; Cheadle, Christopher; Tuder, Rubin; Dietz, Harry C.; Mitzner, Wayne; Wise, Robert; Neptune, Enid

    2011-01-01

    Chronic obstructive pulmonary disease (COPD) is a prevalent smoking-related disease for which no disease-altering therapies currently exist. As dysregulated TGF-β signaling associates with lung pathology in patients with COPD and in animal models of lung injury induced by chronic exposure to cigarette smoke (CS), we postulated that inhibiting TGF-β signaling would protect against CS-induced lung injury. We first confirmed that TGF-β signaling was induced in the lungs of mice chronically exposed to CS as well as in COPD patient samples. Importantly, key pathological features of smoking-associated lung disease in patients, e.g., alveolar injury with overt emphysema and airway epithelial hyperplasia with fibrosis, accompanied CS-induced alveolar cell apoptosis caused by enhanced TGF-β signaling in CS-exposed mice. Systemic administration of a TGF-β–specific neutralizing antibody normalized TGF-β signaling and alveolar cell death, conferring improved lung architecture and lung mechanics in CS-exposed mice. Use of losartan, an angiotensin receptor type 1 blocker used widely in the clinic and known to antagonize TGF-β signaling, also improved oxidative stress, inflammation, metalloprotease activation and elastin remodeling. These data support our hypothesis that inhibition of TGF-β signaling through angiotensin receptor blockade can attenuate CS-induced lung injury in an established murine model. More importantly, our findings provide a preclinical platform for the development of other TGF-β–targeted therapies for patients with COPD. PMID:22182843

  4. Blockade of cannabinoid 1 receptor improves GLP-1R mediated insulin secretion in mice.

    PubMed

    González-Mariscal, Isabel; Krzysik-Walker, Susan M; Kim, Wook; Rouse, Michael; Egan, Josephine M

    2016-03-05

    The cannabinoid 1 receptor (CB1) is an important regulator of energy metabolism. Reports of in vivo and in vitro studies give conflicting results regarding its role in insulin secretion, possibly due to circulatory factors, such as incretins. We hypothesized that this receptor may be a regulator of the entero-insular axis. We found that despite lower food consumption and lower body weight postprandial GLP-1 plasma concentrations were increased in CB1(-/-) mice compared to CB1(+/+) mice administered a standard diet or high fat/sugar diet. Upon exogenous GLP-1 treatment, CB1(-/-) mice had increased glucose-stimulated insulin secretion. In mouse insulinoma cells, cannabinoids reduced GLP-1R-mediated intracellular cAMP accumulation and subsequent insulin secretion. Importantly, such effects were also evident in human islets, and were prevented by pharmacologic blockade of CB1. Collectively, these findings suggest a novel mechanism in which endocannabinoids are negative modulators of incretin-mediated insulin secretion. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  5. Role of dopamine receptor and muscarinic acetylcholine receptor blockade in the antiapomorphine action of neuroleptics

    SciTech Connect

    Zharkovskii, A.M.; Langel, Yu.L.; Chereshka, K.S.; Zharkovskaya, T.A.

    1987-08-01

    The authors analyze the role of dopamine and muscarinic acetylcholine receptor blocking components in the antistereotypic action of neuroleptics with different chemical structure. To determine dopamine-blocking activity in vitro, binding of /sup 3/H-spiperone with membranes of the rat striatum was measured. To study the blocking action of the substances on muscarinic acetylcholine receptors, binding of /sup 3/H-quinuclidinyl benzylate with brain membranes was chosen.

  6. The blockade of GABAA receptors attenuates the inhibitory effect of orexin type 1 receptors antagonist on morphine withdrawal syndrome in rats.

    PubMed

    Davoudi, Mahnaz; Azizi, Hossein; Mirnajafi-Zadeh, Javad; Semnanian, Saeed

    2016-03-23

    The aim of present study was to investigate the involvement of orexin-A neuropeptide in naloxone-induced morphine withdrawal syndrome via modulating neurons bearing GABAA receptors. The locus coeruleus (LC) is a sensitive site for expression of the somatic aspects of morphine withdrawal. Intra-LC microinjection of GABAA receptor agonist attenuates morphine withdrawal signs in rats. Here we studied the influence of LC orexin type 1 receptors blockade by SB-334867 in presence of bicuculline, a GABAA receptor antagonist, on naloxone-induced morphine withdrawal syndrome. Adult male Wistar rats, weighing 250-300 g, were rendered dependent on morphine by subcutaneous (s.c.) injection of increasing morphine doses (6, 16, 26, 36, 46, 56 and 66 mg/kg, 2 ml/kg) at set intervals of 24 h for 7 days. On 8th day, naloxone (3 mg/kg, s.c.) was injected and the somatic signs of morphine withdrawal were evaluated. Intra-LC microinjections (0.2 μl) of either bicuculline (15 μM) or SB-334867 (3 mM) or a combination of both chemicals were done immediately before naloxone injection. Intra-LC microinjection of bicuculline (15 μM) had no significant effect on morphine withdrawal signs, whereas intra-LC microinjection of SB-334867 considerably attenuated morphine withdrawal signs. However, the effect of SB-334867 in attenuating naloxone-induced morphine withdrawal signs was blocked in presence of bicuculline. This finding, for the first time, indicated that orexin-A may participate in expression of naloxone-induced morphine withdrawal syndrome partly through decreasing the activity of neurons bearing GABAA receptors.

  7. Interleukin-1 Receptor Blockade Rescues Myocarditis-Associated End-Stage Heart Failure

    PubMed Central

    Cavalli, Giulio; Foppoli, Marco; Cabrini, Luca; Dinarello, Charles A.; Tresoldi, Moreno; Dagna, Lorenzo

    2017-01-01

    Support measures currently represent the mainstay of treatment for fulminant myocarditis, while effective and safe anti-inflammatory therapies remain an unmet clinical need. However, clinical and experimental evidence indicates that inhibition of the pro-inflammatory cytokine interleukin 1 (IL-1) is effective against both myocardial inflammation and contractile dysfunction. We thus evaluated treatment with the IL-1 receptor antagonist anakinra in a case of heart failure secondary to fulminant myocarditis. A 65-year-old man with T cell lymphoma developed fulminant myocarditis presenting with severe biventricular failure and cardiogenic shock requiring admittance to the intensive care unit and mechanical circulatory and respiratory support. Specifically, acute heart failure and cardiogenic shock were initially treated with non-invasive ventilation and mechanical circulatory support with an intra-aortic balloon pump. Nevertheless, cardiac function deteriorated further, and there were no signs of improvement. Treatment with anakinra, the recombinant form of the naturally occurring IL-1 receptor antagonist, was started at a standard subcutaneous dose of 100 mg/day. We observed a dramatic clinical improvement within 24 h of initiating anakinra. Prompt, progressive amelioration of cardiac function allowed weaning from mechanical circulatory and respiratory support within 72 h of anakinra administration. Recent studies point at inhibition of IL-1 activity as an attractive treatment option for both myocardial inflammation and contractile dysfunction. Furthermore, IL-1 receptor blockade with anakinra is characterized by an extremely rapid onset of action and remarkable safety and may thus be suitable for the treatment of patients critically ill with myocarditis. PMID:28232838

  8. Metabotropic glutamate receptor blockade in nucleus accumbens shell shifts affective valence toward fear and displeasure

    PubMed Central

    Richard, Jocelyn M.; Berridge, Kent C.

    2010-01-01

    Glutamatergic inputs to the nucleus accumbens (NAc) modulate both appetitive and fearful motivation. Pathological disturbances of glutamate signaling in NAc have been suggested to contribute to motivation disorders, ranging from excessive desire in drug addiction to paranoia in schizophrenia. Metabotropic glutamate receptors are of special interest, as metabotropic Group II receptor (mglu2/3) agonists have been proposed as potential treatments for both addiction and schizophrenia. Here we tested whether local mglu2/3 receptor blockade in medial shell of the rat NAc can generate intense distortions of motivation or affect, which might model clinical dysfunction. We found that microinjection of the mglu2/3 antagonist LY341495 suppressed appetitive motivation to eat and drink at sites throughout medial shell. Simultaneously, LY341495 microinjections generated fearful motivation in the form of defensive treading or burying. To assess whether the valence shift extended into a parallel hedonic shift from affective ‘liking’ to ‘disliking,’ we employed the taste reactivity test, which measures affective orofacial reactions to the sensory pleasure or displeasure of tastes. We found that LY341495 microinjections reduced positive ‘liking’ reactions to sucrose and enhanced ‘disliking’ reactions. Overall, mglu2/3 antagonism at most shell sites produced a similar valence shift from positive to negative. This pattern comprised a) generation of fearful behaviors, and b) induction of aversive affective reactions, together with c) loss of appetitive ingestion and d) loss of ‘liking’ for rewards. These results are discussed in terms of implications for clinical disorders and the influence of corticolimbic glutamate inputs to NAc in the generation of motivation and affect. PMID:21198990

  9. Blockade of Serotonin 5-HT2A Receptors Suppresses Behavioral Sensitization and Naloxone-Precipitated Withdrawal Symptoms in Morphine-Treated Mice

    PubMed Central

    Pang, Gang; Wu, Xian; Tao, Xinrong; Mao, Ruoying; Liu, Xueke; Zhang, Yong-Mei; Li, Guangwu; Stackman, Robert W.; Dong, Liuyi; Zhang, Gongliang

    2016-01-01

    The increasing prescription of opioids is fueling an epidemic of addiction and overdose deaths. Morphine is a highly addictive drug characterized by a high relapse rate – even after a long period of abstinence. Serotonin (5-HT) neurotransmission participates in the development of morphine dependence, as well as the expression of morphine withdrawal. In this study, we examined the effect of blockade of 5-HT2A receptors (5-HT2ARs) on morphine-induced behavioral sensitization and withdrawal in male mice. 5-HT2AR antagonist MDL 11,939 (0.5 mg/kg, i.p.) suppressed acute morphine (5.0 mg/kg, s.c.)-induced increase in locomotor activity. Mice received morphine (10 mg/kg, s.c.) twice a day for 3 days and then drug treatment was suspended for 5 days. On day 9, a challenge dose of morphine (10 mg/kg) was administered to induce the expression of behavioral sensitization. MDL 11,939 (0.5 mg/kg, i.p.) pretreatment suppressed the expression of morphine-induced behavioral sensitization. Another cohort of mice received increasing doses of morphine over a 7-day period to induce morphine-dependence. MDL 11,939 (0.5 mg/kg, i.p.) prevented naloxone-precipitated withdrawal in morphine-dependent mice on day 7. Moreover, chronic morphine treatment increased 5-HT2AR protein level and decreased the phosphorylation of extracellular signal-regulated kinases in the prefrontal cortex. Together, these results by the first time demonstrate that 5-HT2ARs modulate opioid dependence and blockade of 5-HT2AR may represent a novel strategy for the treatment of morphine use disorders. Highlights (i) Blockade of 5-HT2A receptors suppresses the expression of morphine-induced behavioral sensitization. (ii) Blockade of 5-HT2A receptors suppresses naloxone-precipitated withdrawal in morphine-treated mice. (iii) Chronic morphine exposure induces an increase in 5-HT2A receptor protein level and a decrease in ERK protein phosphorylation in prefrontal cortex. PMID:28082900

  10. Kappa opioid receptor activation decreases inhibitory transmission and antagonizes alcohol effects in rat central amygdala.

    PubMed

    Gilpin, Nicholas W; Roberto, Marisa; Koob, George F; Schweitzer, Paul

    2014-02-01

    Activation of the kappa opioid receptor (KOR) system mediates negative emotional states and considerable evidence suggests that KOR and their natural ligand, dynorphin, are involved in ethanol dependence and reward. The central amygdala (CeA) plays a major role in alcohol dependence and reinforcement. Dynorphin peptide and gene expression are activated in the amygdala during acute and chronic administration of alcohol, but the effects of activation or blockade of KOR on inhibitory transmission and ethanol effects have not been studied. We used the slice preparation to investigate the physiological role of KOR and interaction with ethanol on GABA(A) receptor-mediated synaptic transmission. Superfusion of dynorphin or U69593 onto CeA neurons decreased evoked inhibitory postsynaptic potentials (IPSPs) in a concentration-dependent manner, an effect prevented by the KOR antagonist norbinaltorphimine (norBNI). Applied alone, norBNI increased GABAergic transmission, revealing a tonic endogenous activity at KOR. Paired-pulse analysis suggested a presynaptic KOR mechanism. Superfusion of ethanol increased IPSPs and pretreatment with KOR agonists diminished the ethanol effect. Surprisingly, the ethanol-induced augmentation of IPSPs was completely obliterated by KOR blockade. Our results reveal an important role of the dynorphin/KOR system in the regulation of inhibitory transmission and mediation of ethanol effects in the CeA.

  11. Kappa Opioid Receptor Activation Decreases Inhibitory Transmission and Antagonizes Alcohol Effects in Rat Central Amygdala

    PubMed Central

    Gilpin, Nicholas W.; Roberto, Marisa; Koob, George F.; Schweitzer, Paul

    2013-01-01

    Activation of the kappa opioid receptor (KOR) system mediates negative emotional states and considerable evidence suggests that KOR and their natural ligand, dynorphin, are involved in ethanol dependence and reward. The central amygdala (CeA) plays a major role in alcohol dependence and reinforcement. Dynorphin peptide and gene expression are activated in the amygdala during acute and chronic administration of alcohol, but the effects of activation or blockade of KOR on inhibitory transmission and ethanol effects have not been studied. We used the slice preparation to investigate the physiological role of KOR and interaction with ethanol on GABAA receptor-mediated synaptic transmission. Superfusion of dynorphin or U69593 onto CeA neurons decreased evoked inhibitory postsynaptic potentials (IPSPs) in a concentration-dependent manner, an effect prevented by the KOR antagonist norbinaltorphimine (norBNI). Applied alone, norBNI increased GABAergic transmission, revealing a tonic endogenous activity at KOR. Paired-pulse analysis suggested a presynaptic KOR mechanism. Superfusion of ethanol increased IPSPs and pretreatment with KOR agonists diminished the ethanol effect. Surprisingly, the ethanol-induced augmentation of IPSPs was completely obliterated by KOR blockade. Our results reveal an important role of the dynorphin/KOR system in the regulation of inhibitory transmission and mediation of ethanol effects in the CeA. PMID:24157490

  12. Effect of angiotensin II type 1 receptor blockade on kidney ischemia/reperfusion; a gender-related difference

    PubMed Central

    Moslemi, Fatemeh; Taheri, Pegah; Azimipoor, Mahdis; Ramtin, Sina; Hashemianfar, Mostafa; Momeni- Ashjerdi, Ali; Eshraghi-Jazi, Fatemeh; Talebi, Ardeshir; Nasri, Hamid; Nematbakhsh, Mehdi

    2016-01-01

    Background: Renal ischemia/reperfusion (I/R) injury may be related to activity of reninangiotensin system (RAS), which is gender-related. In this study, it was attempted to compare the effect of angiotensin II (Ang II) receptor type 1 (AT1R) blockade; losartan in I/R injury in male and female rats. Materials and Methods: Male and female Wistar rats were assigned as sham surgery, control I/R groups treated with vehicle, and case I/R groups treated with losartan (30 mg/kg). Vehicle and losartan were given 2 hours before bilateral kidney ischemia induced by clamping renal arteries for 45 minutes followed by 24 hours of renal reperfusion. Results: The I/R injury significantly increased the serum levels of blood urea nitrogen (BUN) and creatinine (Cr), and kidney tissue damage score in both genders. However, losartan decreased these values in female rats significantly (P < 0.05). This was not observed in male rats. Conclusion: Losartan protects the kidney from I/R injury in female but not in male rats possibly because of gender-related difference of RAS. PMID:27689110

  13. Blockade of vascular endothelial growth factor receptors by tivozanib has potential anti-tumour effects on human glioblastoma cells

    PubMed Central

    Momeny, Majid; Moghaddaskho, Farima; Gortany, Narges K.; Yousefi, Hassan; Sabourinejad, Zahra; Zarrinrad, Ghazaleh; Mirshahvaladi, Shahab; Eyvani, Haniyeh; Barghi, Farinaz; Ahmadinia, Leila; Ghazi-Khansari, Mahmoud; Dehpour, Ahmad R.; Amanpour, Saeid; Tavangar, Seyyed M.; Dardaei, Leila; Emami, Amir H.; Alimoghaddam, Kamran; Ghavamzadeh, Ardeshir; Ghaffari, Seyed H.

    2017-01-01

    Glioblastoma (GBM) remains one of the most fatal human malignancies due to its high angiogenic and infiltrative capacities. Even with optimal therapy including surgery, radiotherapy and temozolomide, it is essentially incurable. GBM is among the most neovascularised neoplasms and its malignant progression associates with striking neovascularisation, evidenced by vasoproliferation and endothelial cell hyperplasia. Targeting the pro-angiogenic pathways is therefore a promising anti-glioma strategy. Here we show that tivozanib, a pan-inhibitor of vascular endothelial growth factor (VEGF) receptors, inhibited proliferation of GBM cells through a G2/M cell cycle arrest via inhibition of polo-like kinase 1 (PLK1) signalling pathway and down-modulation of Aurora kinases A and B, cyclin B1 and CDC25C. Moreover, tivozanib decreased adhesive potential of these cells through reduction of intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1). Tivozanib diminished GBM cell invasion through impairing the proteolytic cascade of cathepsin B/urokinase-type plasminogen activator (uPA)/matrix metalloproteinase-2 (MMP-2). Combination of tivozanib with EGFR small molecule inhibitor gefitinib synergistically increased sensitivity to gefitinib. Altogether, these findings suggest that VEGFR blockade by tivozanib has potential anti-glioma effects in vitro. Further in vivo studies are warranted to explore the anti-tumour activity of tivozanib in combinatorial approaches in GBM. PMID:28287096

  14. Differential effects of presynaptic versus postsynaptic adenosine A2A receptor blockade on Δ9-tetrahydrocannabinol (THC) self-administration in squirrel monkeys.

    PubMed

    Justinová, Zuzana; Redhi, Godfrey H; Goldberg, Steven R; Ferré, Sergi

    2014-05-07

    Different doses of an adenosine A2A receptor antagonist MSX-3 [3,7-dihydro-8-[(1E)-2-(3-ethoxyphenyl)ethenyl]-7 methyl-3-[3-(phosphooxy)propyl-1-(2 propynil)-1H-purine-2,6-dione] were found previously to either decrease or increase self-administration of cannabinoids delta-9-tetrahydrocannabinol (THC) or anandamide in squirrel monkeys. It was hypothesized that the decrease observed with a relatively low dose of MSX-3 was related to blockade of striatal presynaptic A2A receptors that modulate glutamatergic neurotransmission, whereas the increase observed with a higher dose was related to blockade of postsynaptic A2A receptors localized in striatopallidal neurons. This hypothesis was confirmed in the present study by testing the effects of the preferential presynaptic and postsynaptic A2A receptor antagonists SCH-442416 [2-(2-furanyl)-7-[3-(4-methoxyphenyl)propyl]-7H-pyrazolo[4,3-e][1,2,4]triazolo[1,5-c]pyrimidin-5-amine] and KW-6002 [(E)-1, 3-diethyl-8-(3,4-dimethoxystyryl)-7-methyl-3,7-dihydro-1H-purine-2,6-dione], respectively, in squirrel monkeys trained to intravenously self-administer THC. SCH-442416 produced a significant shift to the right of the THC self-administration dose-response curves, consistent with antagonism of the reinforcing effects of THC. Conversely, KW-6002 produced a significant shift to the left, consistent with potentiation of the reinforcing effects of THC. These results show that selectively blocking presynaptic A2A receptors could provide a new pharmacological approach to the treatment of marijuana dependence and underscore corticostriatal glutamatergic neurotransmission as a possible main mechanism involved in the rewarding effects of THC.

  15. Mineralocorticoid receptor blockade but not steroid withdrawal reverses renal fibrosis in deoxycorticosterone/salt rats.

    PubMed

    Lam, Emily Y M; Funder, John W; Nikolic-Paterson, David J; Fuller, Peter J; Young, Morag J

    2006-07-01

    The pathophysiologic effects of nonepithelial mineralocorticoid receptor (MR) activation include vascular inflammation followed by renal and cardiac remodeling in experimental animals. We have recently shown that MR blockade can reverse established cardiac fibrosis and vascular inflammation; the present study explores whether a similar protection is seen in renal tissue. Rats were uninephrectomized and maintained on 0.9% NaCl solution to drink and treated as follows: control, vehicle; deoxycorticosterone (DOC), 20 mg/wk sc for 4 wk and then killed; DOC for 8 wk; DOC for 4 wk and no steroid for wk 5-8; DOC for 8 wk and eplerenone 100 mg/kg.d in the food for wk 5-8. DOC increased renal collagen at 4 and 8 wk; rats given DOC for 4 wk and killed at 8 wk showed levels of fibrosis identical with those killed at 4 wk, whereas rats given DOC for 8 wk plus eplerenone for wk 5-8 were indistinguishable from control. The inflammatory markers ED-1, osteopontin, and cyclooxygenase-2 remained significantly elevated despite the withdrawal of DOC (DOC404), whereas eplerenone restored cyclooxygenase-2 expression (but not that of ED-1 or osteopontin) to control levels. In addition, markers of oxidative stress and TGFbeta were determined. We hypothesize that continuing tubular inflammation and fibrosis despite DOC withdrawal indicates that the renal tissue may reflect MR activation in the context of tissue damage.

  16. N-Methyl-d-Aspartate (NMDA) Receptor Blockade Prevents Neuronal Death Induced by Zika Virus Infection.

    PubMed

    Costa, Vivian V; Del Sarto, Juliana L; Rocha, Rebeca F; Silva, Flavia R; Doria, Juliana G; Olmo, Isabella G; Marques, Rafael E; Queiroz-Junior, Celso M; Foureaux, Giselle; Araújo, Julia Maria S; Cramer, Allysson; Real, Ana Luíza C V; Ribeiro, Lucas S; Sardi, Silvia I; Ferreira, Anderson J; Machado, Fabiana S; de Oliveira, Antônio C; Teixeira, Antônio L; Nakaya, Helder I; Souza, Danielle G; Ribeiro, Fabiola M; Teixeira, Mauro M

    2017-04-25

    Zika virus (ZIKV) infection is a global health emergency that causes significant neurodegeneration. Neurodegenerative processes may be exacerbated by N-methyl-d-aspartate receptor (NMDAR)-dependent neuronal excitoxicity. Here, we have exploited the hypothesis that ZIKV-induced neurodegeneration can be rescued by blocking NMDA overstimulation with memantine. Our results show that ZIKV actively replicates in primary neurons and that virus replication is directly associated with massive neuronal cell death. Interestingly, treatment with memantine or other NMDAR blockers, including dizocilpine (MK-801), agmatine sulfate, or ifenprodil, prevents neuronal death without interfering with the ability of ZIKV to replicate in these cells. Moreover, in vivo experiments demonstrate that therapeutic memantine treatment prevents the increase of intraocular pressure (IOP) induced by infection and massively reduces neurodegeneration and microgliosis in the brain of infected mice. Our results indicate that the blockade of NMDARs by memantine provides potent neuroprotective effects against ZIKV-induced neuronal damage, suggesting it could be a viable treatment for patients at risk for ZIKV infection-induced neurodegeneration.IMPORTANCE Zika virus (ZIKV) infection is a global health emergency associated with serious neurological complications, including microcephaly and Guillain-Barré syndrome. Infection of experimental animals with ZIKV causes significant neuronal damage and microgliosis. Treatment with drugs that block NMDARs prevented neuronal damage both in vitro and in vivo These results suggest that overactivation of NMDARs contributes significantly to the neuronal damage induced by ZIKV infection, and this is amenable to inhibition by drug treatment. Copyright © 2017 Costa et al.

  17. Blockade of hypocretin receptor-1 preferentially prevents cocaine seeking: comparison with natural reward seeking

    PubMed Central

    Martin-Fardon, Rémi; Weiss, Friedbert

    2014-01-01

    Hypothalamic orexin/hypocretin (Orx/Hcrt) peptides participate in the regulation of a wide range of physiological processes and are recruited by drugs of abuse. To advance our understanding of the potential of the Orx/Hcrt receptor-1 (Hcrt-r1) as a treatment target for cocaine addiction, the effect of SB334867, a specific Hcrt-r1 antagonist, on reinstatement elicited by cocaine-associated stimuli vs. stimuli associated with a highly palatable conventional reinforcer (sweetened condensed milk [SCM]) was tested. Two separate groups of male Wistar rats were trained to associate a discriminative stimulus (S+) with the response-contingent availability of cocaine (0.25 mg/0.1 ml/infusion) or SCM (2/1 [v/v]) and subjected to reinstatement tests following extinction, during which the reinforcers and S+ were withheld, of cocaine or SCM-reinforced behavior. Following extinction, presentation of the cocaine or SCM S+ produced comparable recovery of responding. Hcrt-r1 blockade by SB334867 (1–10 mg/kg, IP) dose-dependently and selectively reversed conditioned reinstatement induced by cocaine-related stimuli, without interfering with reward seeking produced by the same stimulus when conditioned to SCM. The findings implicate an important role for Hcrt-r1 in appetitive behavior controlled by reward-related stimuli with selectivity for cocaine seeking and identify Hcrt-r1 as a potential treatment target for cocaine relapse prevention. PMID:24407199

  18. N-Methyl-d-Aspartate (NMDA) Receptor Blockade Prevents Neuronal Death Induced by Zika Virus Infection

    PubMed Central

    Costa, Vivian V.; Del Sarto, Juliana L.; Rocha, Rebeca F.; Silva, Flavia R.; Doria, Juliana G.; Olmo, Isabella G.; Marques, Rafael E.; Queiroz-Junior, Celso M.; Foureaux, Giselle; Araújo, Julia Maria S.; Cramer, Allysson; Real, Ana Luíza C. V.; Ribeiro, Lucas S.; Sardi, Silvia I.; Ferreira, Anderson J.; Machado, Fabiana S.; de Oliveira, Antônio C.; Teixeira, Antônio L.; Nakaya, Helder I.; Souza, Danielle G.

    2017-01-01

    ABSTRACT Zika virus (ZIKV) infection is a global health emergency that causes significant neurodegeneration. Neurodegenerative processes may be exacerbated by N-methyl-d-aspartate receptor (NMDAR)-dependent neuronal excitoxicity. Here, we have exploited the hypothesis that ZIKV-induced neurodegeneration can be rescued by blocking NMDA overstimulation with memantine. Our results show that ZIKV actively replicates in primary neurons and that virus replication is directly associated with massive neuronal cell death. Interestingly, treatment with memantine or other NMDAR blockers, including dizocilpine (MK-801), agmatine sulfate, or ifenprodil, prevents neuronal death without interfering with the ability of ZIKV to replicate in these cells. Moreover, in vivo experiments demonstrate that therapeutic memantine treatment prevents the increase of intraocular pressure (IOP) induced by infection and massively reduces neurodegeneration and microgliosis in the brain of infected mice. Our results indicate that the blockade of NMDARs by memantine provides potent neuroprotective effects against ZIKV-induced neuronal damage, suggesting it could be a viable treatment for patients at risk for ZIKV infection-induced neurodegeneration. PMID:28442607

  19. [The adaptation of AV-nodal conduction time on gliding increase and decrease of atrial frequency before and after autonomic blockade (author's transl)].

    PubMed

    Runge, M; Ehlers, E; Pantlen, H; Luckmann, E

    1979-01-01

    In 19 patients with healthy AV-nodes the adaptation of the intranodal conduction time (A-H time) to gliding increase and decrease in atrial frequency and to the blockade of the autonomic nervous system was investigated using His bundle electrograms. The measurements were performed during right atrial stimulation with three frequencies, each with a duration of one minute, before and after blockade of the parasympathetic (8 pat.; 1 mg atropine i.v.) and the sympathetic (11 pat.; 0.4 mg Visken i.v.) nervous system. Gliding increase and decrease in atrial frequency results in a staircase pattern of A-H-adaptation in 18 of the patients. The height of the steps was identical in both phases of stimulation in each individual patient. One patient showed functional dissociation of intranodal conduction which was different during increase and decrease of atrial frequency. With parasympathetic blockade the staircase behavior of the A-H time basically remained unchanged with the exception of shorter A-H intervals resulting in lower steps. Atropine abolished the functional dissociation of intranodal conduction; thus the drug might prevent reentrytachycardias due to functional dissociation in the AV-node. Sympathetic blockade lengthens the intranodal conduction time; thus shifting the staircase pattern of the A-H time to higher levels. The results are discussed with respect to the electrophysiological characteristics of AV nodal cells as slow response fibers, and to the changes caused by atrial stimulation, acetylcholine and adrenaline.

  20. Effects of angiotensin II (AT1) receptor blockade on cardiac vagal control in heart failure.

    PubMed

    Vaile, J C; Chowdhary, S; Osman, F; Ross, H F; Fletcher, J; Littler, W A; Coote, J H; Townend, J N

    2001-12-01

    The objective of the present study was to determine the autonomic effects of angiotensin II (AT(1)) receptor blocker therapy in heart failure. In a randomized double-blind cross-over study, we compared the effects of candesartan and placebo on baroreflex sensitivity and on heart rate variability at rest, during stress and during 24 h monitoring. Acute effects were assessed 4 h after oral candesartan (8 mg) and chronic effects after 4 weeks of treatment (dose titrated to 16 mg daily). The study group comprised 21 patients with heart failure [mean (S.E.M.) ejection fraction 33% (1%)], in the absence of angiotensin-converting enzyme (ACE) inhibitor therapy. We found that acute candesartan was not different from placebo in its effects on blood pressure or mean RR interval. Chronic candesartan significantly reduced blood pressure [placebo, 137 (3)/82 (3) mmHg; candesartan, 121 (4)/75 (2) mmHg; P<0.001; values are mean (S.E.M.)], but had no effect on mean RR interval [placebo, 857 (25) ms; candesartan, 857 (21) ms]. Compared with placebo there were no significant effects of acute or chronic candesartan on heart rate variability in the time domain and no consistent effects in the frequency domain. Baroreflex sensitivity assessed by the phenylephrine bolus method was significantly increased after chronic candesartan [placebo, 3.5 (0.5) ms/mmHg; candesartan, 4.8 (0.7) ms/mmHg; P<0.05], although there were no changes in cross-spectral baroreflex sensitivity. Thus, in contrast with previous results with ACE inhibitors, angiotensin II receptor blockade in heart failure did not increase heart rate variability, and there was no consistent effect on baroreflex sensitivity.

  1. Angiotensin II type 1 receptor blockade suppresses light-induced neural damage in the mouse retina.

    PubMed

    Narimatsu, Toshio; Ozawa, Yoko; Miyake, Seiji; Nagai, Norihiro; Tsubota, Kazuo

    2014-06-01

    Exposure to light contributes to the development and progression of retinal degenerative diseases. However, the mechanisms underlying light-induced tissue damage are not fully understood. Here, we examined the role of angiotensin II type 1 receptor (AT1R) signaling, which is part of the renin-angiotensin system, in light-induced retinal damage. Light-exposed Balb/c mice that were treated with the AT1R blockers (angiotensin II receptor blockers; ARBs) valsartan, losartan, and candesartan before and after the light exposure exhibited attenuated visual function impairment, compared to vehicle-treated mice. This effect was dose-dependent and observed across the ARB class of inhibitors. Further evaluation of valsartan showed that it suppressed a number of light-induced retinal effects, including thinning of the photoreceptor cell layer caused by apoptosis, shortening of the photoreceptor cell outer segment, and increased levels of reactive oxygen species (ROS). The role of ROS in retinal pathogenesis was investigated further using the antioxidant N-acetyl-l-cysteine (NAC). Treatment of light-exposed mice with NAC before the light exposure suppressed the visual function impairment and photoreceptor cell histological changes due to apoptosis. Moreover, treatment with valsartan or NAC suppressed the induction of c-fos (a component of the AP-1 transcription factor) and the upregulation of fasl (a proapoptotic molecule whose transcript is regulated downstream of AP-1). Our results suggest that AT1R signaling mediates light-induced apoptosis, by increasing the levels of ROS and proapoptotic molecules in the retina. Thus, AT1R blockade may represent a new therapeutic approach for preventing light-induced retinal neural tissue damage. Copyright © 2014 The Authors. Published by Elsevier Inc. All rights reserved.

  2. Pitting type of pretibial edema in a patient with silent thyroiditis successfully treated by angiotensin ii receptor blockade

    PubMed Central

    Kazama, Itsuro; Mori, Yoko; Baba, Asuka; Nakajima, Toshiyuki

    2014-01-01

    Patient: Female, 56 Final Diagnosis: Thyroiditis – silent Symptoms: Palpitations • pretibial pitting edema • short of breath • sweating Medication: — Clinical Procedure: — Specialty: Endocrinology and Metabolic Objective: Unknown etiology Background: Hyper- or hypothyroidism sometimes causes pretibial myxedema characterized by non-pitting infiltration of a proteinaceous ground substance. However, in those patients, the “pitting” type of pretibial edema as a result of increased sodium and fluid retention or vascular hyper-permeability rarely occurs, except in cases complicated by heart failures due to severe cardiomyopathy or pulmonary hypertension. Case Report: A 56-year-old woman developed bilateral pretibial pitting edema, followed by occasional sweating, palpitations, and shortness of breath, which persisted for more than 2 months. The diagnosis of hyperthyroidism due to silent thyroiditis was supported by elevated levels of free thyroxine (T4) and triiodothyronine (T3), with a marked decrease in thyroid-stimulating hormone (TSH), and the negative results for TSH receptor antibodies with typical findings of destructive thyrotoxicosis. Despite her “pitting” type of pretibial edema, a chest radio-graph demonstrated the absence of cardiomyopathy or congestive heart failure. Oral administration of angiotensin II receptor blocker (ARB) was initiated for her systolic hypertension, with a relatively higher elevation of plasma renin activity compared to that of the aldosterone level. Although the symptoms characteristic to hyperthyroidism, such as increased sweating, palpitations and shortness of breath, slowly improved with a spontaneous resolution of the disease, ARB quickly resolved the pretibial pitting edema shortly after the administration.. Conclusions: In this case, increased activity of the renin-angiotensin-aldosterone system stimulated by thyroid hormone was likely responsible for the patient’s pitting type of edema. The pharmacological

  3. Effects of continuous opioid receptor blockade on alcohol intake and up-regulation of opioid receptor subtype signalling in a genetic model of high alcohol drinking.

    PubMed

    Hyytiä, P; Ingman, K; Soini, S L; Laitinen, J T; Korpi, E R

    1999-10-01

    Effects of a continuous naloxone infusion via osmotic pumps on alcohol drinking and opioid receptor density and function in the high-drinking AA (Alko, Alcohol) rats were examined. AA rats were trained to drink 10% (v/v) ethanol in a 1-h limited access procedure and implanted with subcutaneous osmotic pumps delivering either saline, a low dose (0.3 mg/kg per hour), or a high dose (3.0 mg/kg per hour) of naloxone for 7 days. The pumps were then removed and alcohol, food and water intakes were measured for another 4 days. Compared with saline, both naloxone doses significantly suppressed 1-h alcohol intake during the 7-day infusion. The suppression was smaller than that by a bolus injection of the same daily dose 15 min before the session, although a complete blockade of morphine-induced antinociception was achieved even with the smaller naloxone infusion. Significant decreases were also seen in daily food and water intake during the first days, but they quickly returned to their previous baselines. After pump removal, rats of both naloxone-treated groups rapidly increased their alcohol drinking and reached the pretreatment baseline, while their food and water intakes significantly surpassed their baselines. Naloxone infusion at 3.0 mg/kg per hour for 7 days significantly decreased 24-h alcohol drinking without affecting alcohol preference. Twenty-four hours after pump removal, autoradiography with [3H]DAMGO, [3H]DPDPE and [3H]U-69,543 revealed an up-regulation of mu-, delta- and kappa-opioid receptor binding sites in many brain areas of these animals. This receptor up-regulation was functional, because receptor coupling to G-protein activation was enhanced by agonist ligands, as revealed by [35S]GTPgammaS autoradiography. A good correlation existed between ligand binding densities and G-protein activation for mu- and kappa-receptors in control and naloxone-treated brain sections. Furthermore, morphine-induced analgesia in a hot-plate test showed a leftward shift in

  4. Combined, but not individual, blockade of ASIC3, P2X, and EP4 receptors attenuates the exercise pressor reflex in rats with freely perfused hindlimb muscles.

    PubMed

    Stone, Audrey J; Copp, Steven W; Kim, Joyce S; Kaufman, Marc P

    2015-12-01

    In healthy humans, tests of the hypothesis that lactic acid, PGE2, or ATP plays a role in evoking the exercise pressor reflex proved controversial. The findings in humans resembled ours in decerebrate rats that individual blockade of the receptors to lactic acid, PGE2, and ATP had only small effects on the exercise pressor reflex provided that the muscles were freely perfused. This similarity between humans and rats prompted us to test the hypothesis that in rats with freely perfused muscles combined receptor blockade is required to attenuate the exercise pressor reflex. We first compared the reflex before and after injecting either PPADS (10 mg/kg), a P2X receptor antagonist, APETx2 (100 μg/kg), an activating acid-sensing ion channel 3 (ASIC) channel antagonist, or L161982 (2 μg/kg), an EP4 receptor antagonist, into the arterial supply of the hindlimb of decerebrated rats. We then examined the effects of combined blockade of P2X receptors, ASIC3 channels, and EP4 receptors on the exercise pressor reflex using the same doses, intra-arterial route, and time course of antagonist injections as those used for individual blockade. We found that neither PPADS (n = 5), APETx2 (n = 6), nor L161982 (n = 6) attenuated the reflex. In contrast, combined blockade of these receptors (n = 7) attenuated the peak (↓27%, P < 0.019) and integrated (↓48%, P < 0.004) pressor components of the reflex. Combined blockade injected intravenously had no effect on the reflex. We conclude that combined blockade of P2X receptors, ASIC3 channels, and EP4 receptors on the endings of thin fiber muscle afferents is required to attenuate the exercise pressor reflex in rats with freely perfused hindlimbs.

  5. Intravesical TRPV4 blockade reduces repeated variate stress-induced bladder dysfunction by increasing bladder capacity and decreasing voiding frequency in male rats.

    PubMed

    Merrill, Liana; Vizzard, Margaret A

    2014-08-15

    Individuals with functional lower urinary tract disorders including interstitial cystitis (IC)/bladder pain syndrome (BPS) and overactive bladder (OAB) often report symptom (e.g., urinary frequency) worsening due to stress. One member of the transient receptor potential ion channel vanilloid family, TRPV4, has recently been implicated in urinary bladder dysfunction disorders including OAB and IC/BPS. These studies address the role of TRPV4 in stress-induced bladder dysfunction using an animal model of stress in male rats. To induce stress, rats were exposed to 7 days of repeated variate stress (RVS). Quantitative PCR data demonstrated significant (P ≤ 0.01) increases in TRPV4 transcript levels in urothelium but not detrusor smooth muscle. Western blot analyses of split urinary bladders (i.e., urothelium and detrusor) showed significant (P ≤ 0.01) increases in TRPV4 protein expression levels in urothelial tissues but not detrusor smooth muscle. We previously showed that RVS produces bladder dysfunction characterized by decreased bladder capacity and increased voiding frequency. The functional role of TRPV4 in RVS-induced bladder dysfunction was evaluated using continuous, open outlet intravesical infusion of saline in conjunction with administration of a TRPV4 agonist, GSK1016790A (3 μM), a TRPV4 antagonist, HC067047 (1 μM), or vehicle (0.1% DMSO in saline) in control and RVS-treated rats. Bladder capacity, void volume, and intercontraction interval significantly decreased following intravesical instillation of GSK1016790A in control rats and significantly (P ≤ 0.01) increased following administration of HC067047 in RVS-treated rats. These results demonstrate increased TRPV4 expression in the urothelium following RVS and that TRPV4 blockade ameliorates RVS-induced bladder dysfunction consistent with the role of TRPV4 as a promising target for bladder function disorders. Copyright © 2014 the American Physiological Society.

  6. Activation of the Cardiac Renin-Angiotensin System in High Oxygen-Exposed Newborn Rats: Angiotensin Receptor Blockade Prevents the Developmental Programming of Cardiac Dysfunction.

    PubMed

    Bertagnolli, Mariane; Dios, Anne; Béland-Bonenfant, Sarah; Gascon, Gabrielle; Sutherland, Megan; Lukaszewski, Marie-Amélie; Cloutier, Anik; Paradis, Pierre; Schiffrin, Ernesto L; Nuyt, Anne Monique

    2016-04-01

    Newborn rats exposed to high oxygen (O2), mimicking preterm birth-related neonatal stress, develop later in life cardiac hypertrophy, dysfunction, fibrosis, and activation of the renin-angiotensin system. Cardiac renin-angiotensin system activation in O2-exposed adult rats is characterized by an imbalance in angiotensin (Ang) receptors type 1/2 (AT1/2), with prevailing AT1 expression. To study the role of renin-angiotensin system in the developmental programming of cardiac dysfunction, we assessed Ang receptor expression during neonatal high O2 exposure and whether AT1 receptor blockade prevents cardiac alterations in early adulthood. Sprague-Dawley newborn rats were kept with their mother in 80% O2 or room air (control) from days 3 to 10 (P3-P10) of life. Losartan or water was administered by gavage from P8 to P10 (n=9/group). Rats were studied at P3 (before O2 exposure), P5, P10 (end of O2), and P28. Losartan treatment had no impact on growth or kidney development. AT1 and Ang type 2 receptors were upregulated in the left ventricle by high O2 exposure (P5 and P10), which was prevented by Losartan treatment at P10. Losartan prevented the cardiac AT1/2 imbalance at P28. Losartan decreased cardiac hypertrophy and fibrosis and improved left ventricle fraction of shortening in P28 O2-exposed rats, which was associated with decreased oxidation of calcium/calmodulin-dependent protein kinase II, inhibition of the transforming growth factor-β/SMAD3 pathway, and upregulation of cardiac angiotensin-converting enzyme 2. In conclusion, short-term Ang II blockade during neonatal high O2 prevents the development of cardiac alterations later in life in rats. These findings highlight the key role of neonatal renin-angiotensin system activation in the developmental programming of cardiac dysfunction induced by deleterious neonatal conditions.

  7. Blockade of the Renin-Angiotensin system improves insulin receptor signaling and insulin-stimulated skeletal muscle glucose transport in burn injury.

    PubMed

    Kasper, Sherry O; Phillips, Erin E; Castle, Scott M; Daley, Brian J; Enderson, Blaine L; Karlstad, Michael D

    2011-01-01

    Burn injury is associated with a decline in glucose utilization and insulin sensitivity due to alterations in postreceptor insulin signaling pathways. We have reported that blockade of the renin-angiotensin system with losartan, an angiotensin II type 1 (AT1) receptor blocker, improves whole body insulin sensitivity and glucose metabolism after burn injury. This study examines whether losartan improves insulin signaling pathways and insulin-stimulated glucose transport in skeletal muscle in burn-injured rats. Rats were injured by a 30% full-skin-thickness scalding burn and treated with losartan or placebo for 3 days after burn. Insulin signaling pathways were investigated in rectus abdominus muscle taken before and 90 s after intraportal insulin injection (10 U·kg). Insulin-stimulated insulin receptor substrate 1-associated phosphatidylinositol 3-kinase and plasma membrane-associated GLUT4 transporter were substantially increased with losartan treatment in burn-injured animals (59% above sham). Serine phosphorylated AKT/PKB was decreased with burn injury, and this decrease was attenuated with losartan treatment. In a separate group of rats, the effect of insulin on 2-deoxyglucose transport was significantly impaired in burned as compared with sham soleus muscles, in vitro; however, treatment of burned rats with losartan completely abolished the reduction of insulin-stimulated 2-deoxyglucose transport. These findings demonstrate a cross talk between the AT1 and insulin receptor that negatively modulates insulin receptor signaling and suggest a potential role of renin-angiotensin system blockade as a therapeutic strategy for enhancing insulin sensitivity in skeletal muscle and improving whole-body glucose homeostasis in burn injury.

  8. Improvement of skin wound healing in diabetic mice by kinin B2 receptor blockade.

    PubMed

    Desposito, Dorinne; Chollet, Catherine; Taveau, Christopher; Descamps, Vincent; Alhenc-Gelas, François; Roussel, Ronan; Bouby, Nadine; Waeckel, Ludovic

    2016-01-01

    Impaired skin wound healing is a major medical problem in diabetic subjects. Kinins exert a number of vascular and other actions limiting organ damage in ischaemia or diabetes, but their role in skin injury is unknown. We investigated, through pharmacological manipulation of bradykinin B1 and B2 receptors (B1R and B2R respectively), the role of kinins in wound healing in non-diabetic and diabetic mice. Using two mouse models of diabetes (streptozotocin-induced and db/db mice) and non-diabetic mice, we assessed the effect of kinin receptor activation or inhibition by subtype-selective pharmacological agonists (B1R and B2R) and antagonist (B2R) on healing of experimental skin wounds. We also studied effects of agonists and antagonist on keratinocytes and fibroblasts in vitro. Levels of Bdkrb1 (encoding B1R) and Bdkrb2 (encoding B2R) mRNAs increased 1-2-fold in healthy and wounded diabetic skin compared with in non-diabetic skin. Diabetes delayed wound healing. The B1R agonist had no effect on wound healing. In contrast, the B2R agonist impaired wound repair in both non-diabetic and diabetic mice, inducing skin disorganization and epidermis thickening. In vitro, B2R activation unbalanced fibroblast/keratinocyte proliferation and increased keratinocyte migration. These effects were abolished by co-administration of B2R antagonist. Interestingly, in the two mouse models of diabetes, the B2R antagonist administered alone normalized wound healing. This effect was associated with the induction of Ccl2 (encoding monocyte chemoattractant protein 1)/Tnf (encoding tumour necrosis factor α) mRNAs. Thus stimulation of kinin B2 receptor impairs skin wound healing in mice. B2R activation occurs in the diabetic skin and delays wound healing. B2R blockade improves skin wound healing in diabetic mice and is a potential therapeutic approach to diabetic ulcers. © 2016 Authors; published by Portland Press Limited.

  9. Blockade of dopamine D1-family receptors attenuates the mania-like hyperactive, risk-preferring, and high motivation behavioral profile of mice with low dopamine transporter levels.

    PubMed

    Milienne-Petiot, Morgane; Groenink, Lucianne; Minassian, Arpi; Young, Jared W

    2017-10-01

    Patients with bipolar disorder mania exhibit poor cognition, impulsivity, risk-taking, and goal-directed activity that negatively impact their quality of life. To date, existing treatments for bipolar disorder do not adequately remediate cognitive dysfunction. Reducing dopamine transporter expression recreates many bipolar disorder mania-relevant behaviors (i.e. hyperactivity and risk-taking). The current study investigated whether dopamine D1-family receptor blockade would attenuate the risk-taking, hypermotivation, and hyperactivity of dopamine transporter knockdown mice. Dopamine transporter knockdown and wild-type littermate mice were tested in mouse versions of the Iowa Gambling Task (risk-taking), Progressive Ratio Breakpoint Test (effortful motivation), and Behavioral Pattern Monitor (activity). Prior to testing, the mice were treated with the dopamine D1-family receptor antagonist SCH 23390 hydrochloride (0.03, 0.1, or 0.3 mg/kg), or vehicle. Dopamine transporter knockdown mice exhibited hyperactivity and hyperexploration, hypermotivation, and risk-taking preference compared with wild-type littermates. SCH 23390 hydrochloride treatment decreased premature responding in dopamine transporter knockdown mice and attenuated their hypermotivation. SCH 23390 hydrochloride flattened the safe/risk preference, while reducing activity and exploratory levels of both genotypes similarly. Dopamine transporter knockdown mice exhibited mania-relevant behavior compared to wild-type mice. Systemic dopamine D1-family receptor antagonism attenuated these behaviors in dopamine transporter knockdown, but not all effects were specific to only the knockdown mice. The normalization of behavior via blockade of dopamine D1-family receptors supports the hypothesis that D1 and/or D5 receptors could contribute to the mania-relevant behaviors of dopamine transporter knockdown mice.

  10. Neurokinin-1 receptors are decreased in major depressive disorder.

    PubMed

    Stockmeier, Craig A; Shi, Xiaochun; Konick, Lisa; Overholser, James C; Jurjus, George; Meltzer, Herbert Y; Friedman, Lee; Blier, Pierre; Rajkowska, Grazyna

    2002-07-02

    Treatment with an antagonist at the neurokinin-1 (NK-1) receptor may alleviate depression, however the brain region(s) in which the NK-1 receptor antagonist exerts its therapeutic effect is unknown. [125I]BH-Substance P was used to measure NK-1 receptors postmortem in cytoarchitectonically defined areas of rostral orbitofrontal cortex (Brodmann's area 47) of subjects with major depressive disorder (n = 12, six females) and psychiatrically normal subjects (n = 11, five females). Six subjects with depression died by suicide. Subjects with depression showed decreased binding to NK-1 receptors across all cortical layers (p = 0.024). The pathophysiology of depression, and the reported therapeutic benefit of NK-1 receptor antagonists, may thus involve NK-1 receptors in prefrontal cortex.

  11. Obesity and gastrointestinal hormones-dual effect of angiotensin II receptor blockade and a partial agonist of PPAR-γ.

    PubMed

    Nakagami, Hironori; Morishita, Ryuichi

    2011-03-01

    Obesity is strongly associated with type 2 diabetes, hypertension, and hyperlipidemia, which is one of the leading causes of mortality and morbidity worldwide. It is now clear that gut hormones play a role in the regulation of body weight and represent therapeutic targets for the future treatment of obesity. Recent evidence demonstrated that dysregulation of adipocytokine functions seen in abdominal obesity may be involved in the pathogenesis of the metabolic syndrome. Angiotensinogen, the precursor of angiotensin (Ang) II, is produced primarily in the liver, but also in adipose tissue, where it is up-regulated during the development of obesity and involved in blood pressure regulation and adipose tissue growth. Importantly, blockade of the RAS attenuates weight gain and adiposity by enhanced energy expenditure. The favorable metabolic effects of telmisartan have been related to its Ang II receptor blockade and action as a partial agonist of peroxisome proliferators activated receptor (PPAR)-γ. PPARγ plays an important role in regulating carbohydrate and lipid metabolism, and ligands for PPARγ can improve insulin sensitivity and reduce triglyceride levels. We designed a comparative study of telmisartan and losartan in ApoE-deficient mice. Treatment with telmisartan or losartan significantly reduced the development of lipid-rich plaque. However, treatment with telmisartan significantly improved endothelial dysfunction and inhibited lipid accumulation in the liver. These favorable characteristics of telmisartan might be due to its action as a partial agonist of PPAR-γ, beyond its blood pressure-lowering effect, through Ang II blockade, which may be called "metabosartan".

  12. Blockade of muscarinic acetylcholine receptors in the ventral tegmental area disrupts food-related learning in rats.

    PubMed

    Sharf, Ruth; Ranaldi, Robert

    2006-01-01

    Stimulation of ventral tegmental area (VTA) muscarinic acetylcholine receptors (mAChRs) is implicated in feeding. To investigate the effects of mAChR blockade in the VTA on food-related learning. In experiment 1, rats (N=12) were placed in chambers containing food and received microinjections of 0 or 5 microg/0.5 microl scopolamine prior to the first four feeding sessions and the alternate dose prior to the tenth feeding session. In experiment 2 (N=9), the effects of daily microinjections of scopolamine on lever pressing under a progressive ratio schedule of food reinforcement were tested. In experiment 3 (N=34), the effects of daily microinjections of scopolamine on lever pressing maintained by conditioned reward were investigated. In experiment 1, all rats demonstrated low consumption during session 1. However, pellet consumption for rats initially pretreated with the 0-microg dose rose to and stayed at maximal levels for the remaining sessions, even when pretreated with the 5-microg dose during the tenth session. Pellet consumption for rats initially pretreated with the 5-microg dose remained low, even for the first two sessions following the cessation of scopolamine pretreatment, and gradually rose to maximal levels by the eighth session. In experiment 2, scopolamine significantly decreased break points. In experiment 3, scopolamine failed to significantly decrease responding specifically on the lever producing the conditioned reward. Altogether, these data suggest that VTA mAChR stimulation is involved in feeding and food-related learning but may not be involved in responding maintained by conditioned reward.

  13. Determinants and Changes Associated with Aldosterone Breakthrough after Angiotensin II Receptor Blockade in Patients with Type 2 Diabetes with Overt Nephropathy

    PubMed Central

    Moranne, Olivier; Bakris, George; Fafin, Coraline; Favre, Guillaume; Pradier, Christian

    2013-01-01

    Summary Background and objectives Inhibition of the renin-angiotensin-aldosterone system decreases proteinuria and slows estimated GFR decline in patients with type 2 diabetes mellitus with overt nephropathy. Serum aldosterone levels may increase during renin-angiotensin-aldosterone system blockade. The determinants and consequences of this aldosterone breakthrough remain unknown. Design, setting, participants, & measurements This study examined the incidence, determinants, and changes associated with aldosterone breakthrough in a posthoc analysis of a randomized study that compared the effect of two angiotensin II receptor blockers in patients with type 2 diabetes mellitus with overt nephropathy. Results Of 567 of 860 participants included in this posthoc analysis, 28% of participants developed aldosterone breakthrough, which was defined by an increase greater than 10% over baseline values of serum aldosterone levels after 1 year of angiotensin II receptor blocker treatment. Factors independently associated with aldosterone breakthrough at 1 year were lower serum aldosterone and potassium levels at baseline, higher decreases in sodium intake, systolic BP, and estimated GFR from baseline to 1 year, and use of losartan versus telmisartan. Aldosterone breakthrough at 6 months was not sustained at 1 year in 69% of cases, and it did not predict estimated GFR decrease and proteinuria increase between 6 months and 1 year. Conclusions Aldosterone breakthrough is a frequent event 1 year after initiating renin-angiotensin-aldosterone system blockade, particularly in participants exposed to intensive lowering of BP with sodium depletion and short-acting angiotensin II receptor blockers. Short-term serum aldosterone level increases at 6 months are not associated with negative kidney outcomes between 6 months and 1 year. PMID:23929924

  14. Amelioration strategies fail to prevent tobacco smoke effects on neurodifferentiation: Nicotinic receptor blockade, antioxidants, methyl donors.

    PubMed

    Slotkin, Theodore A; Skavicus, Samantha; Card, Jennifer; Levin, Edward D; Seidler, Frederic J

    2015-07-03

    Tobacco smoke exposure is associated with neurodevelopmental disorders. We used neuronotypic PC12 cells to evaluate the mechanisms by which tobacco smoke extract (TSE) affects neurodifferentiation. In undifferentiated cells, TSE impaired DNA synthesis and cell numbers to a much greater extent than nicotine alone; TSE also impaired cell viability to a small extent. In differentiating cells, TSE enhanced cell growth at the expense of cell numbers and promoted emergence of the dopaminergic phenotype. Nicotinic receptor blockade with mecamylamine was ineffective in preventing the adverse effects of TSE and actually enhanced the effect of TSE on the dopamine phenotype. A mixture of antioxidants (vitamin C, vitamin E, N-acetyl-l-cysteine) provided partial protection against cell loss but also promoted loss of the cholinergic phenotype in response to TSE. Notably, the antioxidants themselves altered neurodifferentiation, reducing cell numbers and promoting the cholinergic phenotype at the expense of the dopaminergic phenotype, an effect that was most prominent for N-acetyl-l-cysteine. Treatment with methyl donors (vitamin B12, folic acid, choline) had no protectant effect and actually enhanced the cell loss evoked by TSE; they did have a minor, synergistic interaction with antioxidants protecting against TSE effects on growth. Thus, components of tobacco smoke perturb neurodifferentiation through mechanisms that cannot be attributed to the individual effects of nicotine, oxidative stress or interference with one-carbon metabolism. Consequently, attempted amelioration strategies may be partially effective at best, or, as seen here, can actually aggravate injury by interfering with normal developmental signals and/or by sensitizing cells to TSE effects on neurodifferentiation.

  15. Interleukin-6 receptor alpha blockade improves skin lesions in a murine model of systemic lupus erythematosus.

    PubMed

    Birner, Peter; Heider, Susanne; Petzelbauer, Peter; Wolf, Peter; Kornauth, Christoph; Kuroll, Madeleine; Merkel, Olaf; Steiner, Günter; Kishimoto, Tadamitsu; Rose-John, Stefan; Soleiman, Afschin; Moriggl, Richard; Kenner, Lukas

    2016-04-01

    Systemic lupus erythematosus (SLE) is an autoimmune disease, characterized by antinuclear autoantibodies (ANA) and immunocomplexes, commonly affecting kidneys, skin, heart, lung or even the brain. We have shown that JunB(Δep) mice develop a SLE phenotype linked to increased epidermal Interleukin (IL)-6 secretion. Blocking of IL-6 receptor alpha (IL-6Rα) is considered as therapeutic strategy for the treatment of SLE. JunB(Δep) and wild-type mice were treated for short (5 weeks) or long term (21 weeks) with the IL-6Rα-blocking antibody MR16-1. Skin and kidney of mice were investigated by histology and immunofluorescence, and in addition, kidneys were analysed by electron microscopy. Furthermore, soluble IL-6R (sIL-6R), antihistone and antinucleosome antibodies levels were measured and associated with disease parameters. Treatment with MR16-1 resulted in significant improvement of SLE-like skin lesions in JunB(Δep) mice, compared to untreated mice. The sIL-6R amount upon long-term treatment with MR16-1 was significantly higher in JunB(Δep) versus untreated JunB(Δep) (P = 0.034) or wild-type mice (P = 0.034). MR16-1 treatment over these time spans did not significantly improve kidney pathology of immunoglobulin deposits causing impaired function. Significantly higher antihistone (P = 0.028) and antinucleosome antibody levels (P = 0.028) were measured in MR16-1-treated JunB(Δep) mice after treatment compared to levels before therapy. In conclusion, blockade of IL-6Rα improves skin lesions in a murine SLE model, but does not have a beneficial effect on autoimmune-mediated kidney pathology. Inhibition of IL-6R signalling might be helpful in lupus cases with predominant skin involvement, but combinatorial treatment might be required to restrain autoantibodies.

  16. Amelioration Strategies Fail To Prevent Tobacco Smoke Effects On Neurodifferentiation: Nicotinic Receptor Blockade, Antioxidants, Methyl Donors

    PubMed Central

    Slotkin, Theodore A.; Skavicus, Samantha; Card, Jennifer; Levin, Edward D.; Seidler, Frederic J.

    2015-01-01

    Tobacco smoke exposure is associated with neurodevelopmental disorders. We used neuronotypic PC12 cells to evaluate the mechanisms by which tobacco smoke extract (TSE) affects neurodifferentiation. In undifferentiated cells, TSE impaired DNA synthesis and cell numbers to a much greater extent than nicotine alone; TSE also impaired cell viability to a small extent. In differentiating cells, TSE enhanced cell growth at the expense of cell numbers and promoted emergence of the dopaminergic phenotype. Nicotinic receptor blockade with mecamylamine was ineffective in preventing the adverse effects of TSE and actually enhanced the effect of TSE on the dopamine phenotype. A mixture of antioxidants (Vitamin C, Vitamin E, N-acetyl-L-cysteine) provided partial protection against cell loss but also promoted loss of the cholinergic phenotype in response to TSE. Notably, the antioxidants themselves altered neurodifferentiation, reducing cell numbers and promoting the cholinergic phenotype at the expense of the dopaminergic phenotype, an effect that was most prominent for N-acetyl-L-cysteine. Treatment with methyl donors (Vitamin B12, folic acid, choline) had no protectant effect and actually enhanced the cell loss evoked by TSE; they did have a minor, synergistic interaction with antioxidants protecting against TSE effects on growth. Thus, components of tobacco smoke perturb neurodifferentiation through mechanisms that cannot be attributed to the individual effects of nicotine, oxidative stress or interference with one-carbon metabolism. Consequently, attempted amelioration strategies may be partially effective at best, or, as seen here, can actually aggravate injury interfering with normal developmental signals and/or by sensitizing cells to TSE effects on neurodifferentiation. PMID:25891525

  17. Blockade of dopamine d4 receptors attenuates reinstatement of extinguished nicotine-seeking behavior in rats.

    PubMed

    Yan, Yijin; Pushparaj, Abhiram; Le Strat, Yann; Gamaleddin, Islam; Barnes, Chanel; Justinova, Zuzana; Goldberg, Steven R; Le Foll, Bernard

    2012-02-01

    Since cloning of the dopamine receptor D4 (DRD4), its role in the brain has remained unclear. It has been reported that polymorphism of the DRD4 gene in humans is associated with reactivity to cues related to tobacco smoking. However, the role of DRD4 in animal models of nicotine addiction has seldom been explored. In our study, male Long-Evans rats learned to intravenously self-administer nicotine under a fixed-ratio (FR) schedule of reinforcement. Effects of the selective DRD4 antagonist L-745,870 were evaluated on nicotine self-administration behavior and on reinstatement of extinguished nicotine-seeking behavior induced by nicotine-associated cues or by priming injections of nicotine. L-745,870 was also tested on reinstatement of extinguished food-seeking behavior as a control. In addition, the selective DRD4 agonist PD 168,077 was tested for its ability to reinstate extinguished nicotine-seeking behavior. Finally, L-745,870 was tested in Sprague Dawley rats trained to discriminate administration of 0.4 mg/kg nicotine from vehicle under an FR schedule of food delivery. L-745,870 significantly attenuated reinstatement of nicotine-seeking induced by both nicotine-associated cues and nicotine priming. In contrast, L-745,870 did not affect established nicotine self-administration behavior or reinstatement of food-seeking behavior induced by food cues or food priming. L-745,870 did not produce nicotine-like discriminative-stimulus effects and did not alter discriminative-stimulus effects of nicotine. PD 168,077 did not reinstate extinguished nicotine-seeking behavior. As DRD4 blockade by L-745,870 selectively attenuated both cue- and nicotine-induced reinstatement of nicotine-seeking behavior, without affecting cue- or food-induced reinstatement of food-seeking behavior, DRD4 antagonists are potential therapeutic agents against tobacco smoking relapse.

  18. Blockade of Dopamine D4 Receptors Attenuates Reinstatement of Extinguished Nicotine-Seeking Behavior in Rats

    PubMed Central

    Yan, Yijin; Pushparaj, Abhiram; Le Strat, Yann; Gamaleddin, Islam; Barnes, Chanel; Justinova, Zuzana; Goldberg, Steven R; Le Foll, Bernard

    2012-01-01

    Since cloning of the dopamine receptor D4 (DRD4), its role in the brain has remained unclear. It has been reported that polymorphism of the DRD4 gene in humans is associated with reactivity to cues related to tobacco smoking. However, the role of DRD4 in animal models of nicotine addiction has seldom been explored. In our study, male Long-Evans rats learned to intravenously self-administer nicotine under a fixed-ratio (FR) schedule of reinforcement. Effects of the selective DRD4 antagonist L-745,870 were evaluated on nicotine self-administration behavior and on reinstatement of extinguished nicotine-seeking behavior induced by nicotine-associated cues or by priming injections of nicotine. L-745,870 was also tested on reinstatement of extinguished food-seeking behavior as a control. In addition, the selective DRD4 agonist PD 168,077 was tested for its ability to reinstate extinguished nicotine-seeking behavior. Finally, L-745,870 was tested in Sprague Dawley rats trained to discriminate administration of 0.4 mg/kg nicotine from vehicle under an FR schedule of food delivery. L-745,870 significantly attenuated reinstatement of nicotine-seeking induced by both nicotine-associated cues and nicotine priming. In contrast, L-745,870 did not affect established nicotine self-administration behavior or reinstatement of food-seeking behavior induced by food cues or food priming. L-745,870 did not produce nicotine-like discriminative-stimulus effects and did not alter discriminative-stimulus effects of nicotine. PD 168,077 did not reinstate extinguished nicotine-seeking behavior. As DRD4 blockade by L-745,870 selectively attenuated both cue- and nicotine-induced reinstatement of nicotine-seeking behavior, without affecting cue- or food-induced reinstatement of food-seeking behavior, DRD4 antagonists are potential therapeutic agents against tobacco smoking relapse. PMID:22030716

  19. Impaired off-line consolidation of motor memories after combined blockade of cholinergic receptors during REM sleep-rich sleep.

    PubMed

    Rasch, Björn; Gais, Steffen; Born, Jan

    2009-06-01

    Rapid eye movement (REM) sleep has been considered important for the consolidation of memories, particularly of procedural skills. REM sleep, in contrast to slow-wave sleep (SWS), is hallmarked by the high, wake-like activity of the neurotransmitter acetylcholine (ACh), which promotes certain synaptic plastic processes underlying the formation of memories. Here, we show in healthy young men that off-line consolidation of a motor skill during a period of late sleep with high amounts of REM sleep depends essentially on high cholinergic activity. After a 3-h sleep period during the early night to satisfy the need for SWS, subjects learned a procedural finger sequence tapping task and a declarative word-pair learning task. After learning, they received either placebo or a combination of the muscarinic receptor antagonist scopolamine (4 microg/kg bodyweight, intravenously) and the nicotinic receptor antagonist mecamylamine (5 mg, orally), and then slept for another 3 h, ie, the late nocturnal sleep period, which is dominated by REM sleep. Retrieval was tested the following evening. Combined cholinergic receptor blockade significantly impaired motor skill consolidation, whereas word-pair memory remained unaffected. Additional data show that the impairing effect of cholinergic receptor blockade is specific to sleep-dependent consolidation of motor skill and does not occur during a wake-retention interval. Taken together, these results identify high cholinergic activity during late, REM sleep-rich sleep as an essential factor promoting sleep-dependent consolidation of motor skills.

  20. Local GABA receptor blockade reveals hindlimb responses in the SI forelimb-stump representation of neonatally amputated rats.

    PubMed

    Pluto, Charles P; Lane, Richard D; Rhoades, Robert W

    2004-07-01

    In adult rats that sustained forelimb amputation on the day of birth, there are numerous multi-unit recording sites in the forelimb-stump representation of primary somatosensory cortex (SI) that also respond to cutaneous stimulation of the hindlimb when cortical receptors for GABA are blocked. These normally suppressed hindlimb inputs originate in the SI hindlimb representation and synapse in the dysgranular cortex before exciting SI forelimb-stump neurons. In our previous studies, GABA (A + B) receptor blockade was achieved by topically applying a bicuculline methiodide/saclofen solution (BMI/SAC) to the cortical surface. This treatment blocks receptors throughout SI and does not allow determination of where along the above circuit the GABA-mediated suppression of hindlimb information occurs. In this study, focal injections of BMI/SAC were delivered to three distinct cortical regions that are involved in the hindlimb-to-forelimb-stump pathway. Blocking GABA receptors in the SI hindlimb representation and in the dysgranular cortex was largely ineffective in revealing hindlimb inputs ( approximately 10% of hindlimb inputs were revealed in both cases). In contrast, when the blockade was targeted at forelimb-stump recording sites, >80% of hindlimb inputs were revealed. Thus GABAergic interneurons within the forelimb-stump representation suppress the expression of reorganized hindlimb inputs to the region. A circuit model incorporating these and previous observations is presented and discussed.

  1. Angiotensin 1-7 Receptor and Angiotensin II Receptor 2 Blockades Prevent the Increased Serum and Kidney Nitric Oxide Levels in Response to Angiotensin II Administration: Gender-Related Difference

    PubMed Central

    Safari, Tahereh; Nematbakhsh, Mehdi

    2013-01-01

    Background: The angiotensin II (Ang II) receptor 2 (AT2R) and angiotensin 1-7 receptor (masR) expression in the kidney are gender-related. We attempted to compare the response of nitric oxide (NO) production to Ang II administration, with and without AT2R and masR blockades, using A-779 and PD123319 in male and female rats. Methods: Anesthetized and catheterized male and female Wistar rats were subjected to one-hour continuous infusion of Ang II (~20 μg/kg/hour), with and without masR and AT2R blockades. The level of the NO metabolite (nitrite) was measured before and after the experiment in rat serum and in the homogenized kidney tissue. Results: The basal data indicated that no sex difference in the serum level of nitrite could be detected before Ang II infusion. However, administration of Ang II in male and female rats caused a gender difference in the nitrite level, which resulted in the serum level of the nitrite significantly increasing in males (P < 0.05) when compared with the females. In addition, masR blockade or co-blockade of masR and AT2R in male rats abolished the gender difference related to the effect of Ang II on nitrite production. In the presence of masR and AT2R, or when masR alone was blocked, the level of nitrite in the kidney, in response to the Ang II infusion was not significantly different between the two sexes. On the contrary, masR and AT2R co-blockades significantly decreased the kidney nitrite concentration response to Ang II administration in both male and female rats (P < 0.05), but no sex difference was detected. Conclusions: The renal vasculature of male rats may provide more response to Ang II administration-induced NO, which is dependent on masR and AT2R. During dual masR + AT2R blockades, the kidney NO formation wasreduced in a non-gender related manner. PMID:23626887

  2. Combined blockade of ADP receptors and PI3-kinase p110β fully prevents platelet and leukocyte activation during hypothermic extracorporeal circulation.

    PubMed

    Krajewski, Stefanie; Kurz, Julia; Geisler, Tobias; Peter, Karlheinz; Wendel, Hans Peter; Straub, Andreas

    2012-01-01

    Extracorporeal circulation (ECC) and hypothermia are used to maintain stable circulatory parameters and improve the ischemia tolerance of patients in cardiac surgery. However, ECC and hypothermia induce activation mechanisms in platelets and leukocytes, which are mediated by the platelet agonist ADP and the phosphoinositide-3-kinase (PI3K) p110β. Under clinical conditions these processes are associated with life-threatening complications including thromboembolism and inflammation. This study analyzes effects of ADP receptor P(2)Y(12) and P(2)Y(1) blockade and PI3K p110β inhibition on platelets and granulocytes during hypothermic ECC. Human blood was treated with the P(2)Y(12) antagonist 2-MeSAMP, the P(2)Y(1) antagonist MRS2179, the PI3K p110β inhibitor TGX-221, combinations thereof, or PBS and propylene glycol (controls). Under static in vitro conditions a concentration-dependent effect regarding the inhibition of ADP-induced platelet activation was found using 2-MeSAMP or TGX-221. Further inhibition of ADP-mediated effects was achieved with MRS2179. Next, blood was circulated in an ex vivo ECC model at 28°C for 30 minutes and various platelet and granulocyte markers were investigated using flow cytometry, ELISA and platelet count analysis. GPIIb/IIIa activation induced by hypothermic ECC was inhibited using TGX-221 alone or in combination with P(2)Y blockers (p<0.05), while no effect of hypothermic ECC or antiplatelet agents on GPIIb/IIIa and GPIbα expression and von Willebrand factor binding was observed. Sole P(2)Y and PI3K blockade or a combination thereof inhibited P-selectin expression on platelets and platelet-derived microparticles during hypothermic ECC (p<0.05). P(2)Y blockade alone or combined with TGX-221 prevented ECC-induced platelet-granulocyte aggregate formation (p<0.05). Platelet adhesion to the ECC surface, platelet loss and Mac-1 expression on granulocytes were inhibited by combined P(2)Y and PI3K blockade (p<0.05). Combined blockade of P

  3. Combined Blockade of ADP Receptors and PI3-Kinase p110β Fully Prevents Platelet and Leukocyte Activation during Hypothermic Extracorporeal Circulation

    PubMed Central

    Krajewski, Stefanie; Kurz, Julia; Geisler, Tobias; Peter, Karlheinz; Wendel, Hans Peter; Straub, Andreas

    2012-01-01

    Extracorporeal circulation (ECC) and hypothermia are used to maintain stable circulatory parameters and improve the ischemia tolerance of patients in cardiac surgery. However, ECC and hypothermia induce activation mechanisms in platelets and leukocytes, which are mediated by the platelet agonist ADP and the phosphoinositide-3-kinase (PI3K) p110β. Under clinical conditions these processes are associated with life-threatening complications including thromboembolism and inflammation. This study analyzes effects of ADP receptor P2Y12 and P2Y1 blockade and PI3K p110β inhibition on platelets and granulocytes during hypothermic ECC. Human blood was treated with the P2Y12 antagonist 2-MeSAMP, the P2Y1 antagonist MRS2179, the PI3K p110β inhibitor TGX-221, combinations thereof, or PBS and propylene glycol (controls). Under static in vitro conditions a concentration-dependent effect regarding the inhibition of ADP-induced platelet activation was found using 2-MeSAMP or TGX-221. Further inhibition of ADP-mediated effects was achieved with MRS2179. Next, blood was circulated in an ex vivo ECC model at 28°C for 30 minutes and various platelet and granulocyte markers were investigated using flow cytometry, ELISA and platelet count analysis. GPIIb/IIIa activation induced by hypothermic ECC was inhibited using TGX-221 alone or in combination with P2Y blockers (p<0.05), while no effect of hypothermic ECC or antiplatelet agents on GPIIb/IIIa and GPIbα expression and von Willebrand factor binding was observed. Sole P2Y and PI3K blockade or a combination thereof inhibited P-selectin expression on platelets and platelet-derived microparticles during hypothermic ECC (p<0.05). P2Y blockade alone or combined with TGX-221 prevented ECC-induced platelet-granulocyte aggregate formation (p<0.05). Platelet adhesion to the ECC surface, platelet loss and Mac-1 expression on granulocytes were inhibited by combined P2Y and PI3K blockade (p<0.05). Combined blockade of P2Y12, P2Y1 and PI3K p110

  4. Add-on blockade of (pro)renin receptor in imidapril-treated diabetic SHRsp.

    PubMed

    Seki, Yasufumi; Ichihara, Atsuhiro; Mizuguchi, Yuki; Sakoda, Mariyo; Kurauchi-Mito, Asako; Narita, Tatsuya; Kinouchi, Kenichiro; Bokuda, Kanako; Itoh, Hiroshi

    2010-06-01

    To examine the involvement of (pro)renin receptor in the accelerated organ damage in streptozotocin-induced diabetic male SHRsp, the rats fed a high-salt diet were divided into 5 groups: a group treated with the vehicle, a group treated with 15 mg/kg/day of imidapril (ACEi), a group treated with 60 mg/kg/day of imidapril (High ACEi), a group treated with handle region peptide (HRP), and a group treated with both ACEi and HRP (ACEi+HRP). After 8 weeks, the arterial pressure was similar in the vehicle and HRP groups and decreased in the ACEi-treated groups. The renal angiotensin II content decreased similarly in the groups treated with ACEi and/or HRP. Urinary protein excretion also decreased in the ACEi, High ACEi, and HRP groups and significantly further decreased in the ACEi+HRP group. The heart weight of the ACEi+HRP group was significantly lower than that of any other groups, although the cardiac angiotensin II levels decreased similarly in the groups treated with ACEi and/or HRP. Thus, (pro)renin receptor contributes to the accelerated pathogenesis in the heart and kidneys of diabetic SHRsp.

  5. Interleukin-6, A Cytokine Critical to Mediation of Inflammation, Autoimmunity and Allograft Rejection: Therapeutic Implications of IL-6 Receptor Blockade.

    PubMed

    Jordan, Stanley C; Choi, Jua; Kim, Irene; Wu, Gordon; Toyoda, Mieko; Shin, Bonga; Vo, Ashley

    2017-01-01

    The success of kidney transplants is limited by the lack of robust improvements in long-term survival. It is now recognized that alloimmune responses are responsible for the majority of allograft failures. Development of novel therapies to decrease allosensitization is critical. The lack of new drug development in kidney transplantation necessitated repurposing drugs initially developed in oncology and autoimmunity. Among these is tocilizumab (anti-IL-6 receptor [IL-6R]) which holds promise for modulating multiple immune pathways responsible for allograft injury and loss. Interleukin-6 is a cytokine critical to proinflammatory and immune regulatory cascades. Emerging data have identified important roles for IL-6 in innate immune responses and adaptive immunity. Excessive IL-6 production is associated with activation of T-helper 17 cell and inhibition of regulatory T cell with attendant inflammation. Plasmablast production of IL-6 is critical for initiation of T follicular helper cells and production of high-affinity IgG. Tocilizumab is the first-in-class drug developed to treat diseases mediated by IL-6. Data are emerging from animal and human studies indicating a critical role for IL-6 in mediation of cell-mediated rejection, antibody-mediated rejection, and chronic allograft vasculopathy. This suggests that anti-IL-6/IL-6R blockade could be effective in modifying T- and B-cell responses to allografts. Initial data from our group suggest anti-IL-6R therapy is of value in desensitization and prevention and treatment of antibody-mediated rejection. In addition, human trials have shown benefits in treatment of graft versus host disease in matched or mismatched stem cell transplants. Here, we explore the biology of IL-6/IL-6R interactions and the evidence for an important role of IL-6 in mediating allograft rejection.

  6. NR2B receptor blockade inhibits pain-related sensitization of amygdala neurons.

    PubMed

    Ji, Guangchen; Horváth, Csilla; Neugebauer, Volker

    2009-04-28

    Pain-related sensitization and synaptic plasticity in the central nucleus of the amygdala (CeA) depend on the endogenous activation of NMDA receptors and phosphorylation of the NR1 subunit through a PKA-dependent mechanism. Functional NMDA receptors are heteromeric assemblies of NR1 with NR2A-D or NR3A, B subunits. NMDA receptors composed of NR1 and NR2B subunits have been implicated in neuroplasticity and are present in the CeA. Here we used a selective NR2B antagonist (Ro-256981) to determine the contribution of NR2B-containing NMDA receptors to pain-related sensitization of CeA neurons. Extracellular single-unit recordings were made from CeA neurons in anesthetized adult male rats before and during the development of an acute arthritis. Arthritis was induced in one knee joint by intraarticular injections of kaolin and carrageenan. Brief (15 s) mechanical stimuli of innocuous (100-500 g/30 mm2) and noxious (1000-2000 g/30 mm2) intensity were applied to the knee and other parts of the body. In agreement with our previous studies, all CeA neurons developed increased background and evoked activity after arthritis induction. Ro-256981 (1, 10 and 100 muM; 15 min each) was administered into the CeA by microdialysis 5-6 h postinduction of arthritis. Ro-256981 concentration-dependently decreased evoked responses, but not background activity. This pattern of effect is different from that of an NMDA receptor antagonist (AP5) in our previous studies. AP5 (100 microM - 5 mM) inhibited background activity and evoked responses. The differential effects of AP5 and Ro-256981 may suggest that NMDA receptors containing the NR2B subunit are important but not sole contributors to pain-related changes of CeA neurons.

  7. Effect of endothelin-1 and endothelin receptor blockade on the release of microparticles.

    PubMed

    Jung, Christian; Lichtenauer, Michael; Wernly, Bernhard; Franz, Marcus; Goebel, Bjoern; Rafnsson, Arnar; Figulla, Hans-Reiner; Pernow, John

    2016-08-01

    Increased levels of endothelial cell microparticles (EMP) are known to reflect endothelial dysfunction (ED). In diabetes mellitus type 2 (T2DM), the expression of endothelin (ET)-1 is increased. As treatment with an ET-1 antagonist significantly inhibited atherosclerosis in animal models, we sought to investigate whether treatment with ET-1 antagonists affects EMP levels in vitro and in vivo in patients with T2DM. In vitro study: Human umbilical vein endothelial cells (HUVEC) were stimulated with ET-1 alone and ET-1 in combination with a dual ET-A and ET-B endothelin receptor blocker. In vivo study: Patients with T2DM were randomized to treatment with the ET receptor antagonist bosentan or placebo. After 4 weeks, the patients were re-examined and blood samples were obtained. EMP counts in supernatants and plasma samples were determined using flow cytometry. In vitro study: In supernatants of ET-1-stimulated HUVECs, the increased release of EMP was reduced significantly by co-incubation with an ET-1 receptor antagonist (e.g. CD31+/CD42b-EMP decreased from 37·1% ± 2·8 to 31·5% ± 2·8 SEM, P = 0·0078). In vivo study: No changes in EMP levels in blood samples of patients with T2DM were found after 4 weeks of bosentan treatment (n = 36, P = ns). Our in vitro results suggest that ET-1 stimulates the release of EMP from HUVECs via a receptor-dependent mechanism. Co-incubation with an endothelin receptor blocker abolished ET-1-dependent EMP release. However, treatment with bosentan for 4 weeks failed to alter EMP levels in patients with T2DM. Other factors seem to have influenced EMP release in patients with T2DM independent of ET-1 receptor-mediated mechanisms. © 2016 Stichting European Society for Clinical Investigation Journal Foundation.

  8. [A case of prolonged neuromuscular blockade possibly related to a high anti-acetylcholine receptor antibody level].

    PubMed

    Kido, Koji; Uchida, Tokujiro; Makita, Koshi

    2013-04-01

    Prolonged neuromuscular blockade is a relatively common complication of general anesthesia. Some previous reports have shown that positive serum anti-acetylcholine receptor antibody (AChR Ab) might contribute to this complication. We experienced a case of a 69-year-old woman with prolonged neuromuscular blockade after laparoscopic sigmoid colectomy under general anesthesia using rocuronium. A high level of anti-AChR Ab (45 nmol x l-1) was found in postoperative examination and the patient had progressive muscle weakness for six months after the operation. Although this patient had mediastinal tumor diagnosed as thymic carcinoma two years before the operation, preoperative clinical evaluation was negative for myasthenia gravis (MG) and the tumor was in remission at the operation. These observations suggest that preoperative measurement of anti-AChR Ab level might be recommended for patients with mediastinal tumor regardless of symptoms of MG and that neuromuscular blocking agents should be administrated carefully in anti-AChR Ab positive patients under monitoring of the neuromuscular blockade.

  9. Angiotensin Receptor Blockade With Candesartan Attenuates Atherosclerosis, Plaque Disruption, and Macrophage Accumulation Within the Plaque in a Rabbit Model

    PubMed Central

    Perez, Alexandra S.; Nasser, Imad; Stewart, Robert; Vaidya, Anand; Al Ammary, Fawaz; Schmidt, Ben; Horowitz, Gary; Dolgoff, Jennifer; Hamilton, James; Quist, William C.

    2010-01-01

    Background Little is known about whether direct angiotensin receptor blockade can reduce atherosclerosis and plaque disruption. This study evaluated the effect of angiotensin receptor blockade on both the development of atherosclerosis and the disruption of plaque in a modified Constantinides animal model. Methods and Results Twenty-eight New Zealand White rabbits underwent aortic balloon injury followed by a 1% cholesterol diet for 8 weeks. Thirteen rabbits received candesartan at 0.5 mg · kg−1 · d−1 beginning 2 days before aortic balloon injury and continued for the total 8 weeks of the cholesterol diet. The rabbits were then pharmacologically triggered and humanely killed, and their aortas were analyzed. The degree of atherosclerosis was determined by intima-media ratio of the infrarenal portion of the aorta. The frequency of intra-aortic thrombosis, a measure of plaque disruption, and the percentages of macrophage area and collagen-staining area of the plaque were determined. Candesartan-treated rabbits had less atherosclerosis (intima-media infrarenal aorta ratio of 1.18±0.08 versus 1.57±0.08 [mean±SEM] for the placebo group, P<0.001); fewer thrombi (3 of 13 versus 11 of 15; P<0.05); lower percentage area of macrophages to total plaque (18.8±2.7% versus 27±2.5%, P<0.05); and higher collagen to total plaque area (45±3% versus 35±2%, P<0.01). Conclusions These results demonstrate that angiotensin receptor blockade attenuates the degree of atherosclerosis and reduces both plaque disruption and macrophage accumulation while increasing collagen deposition in the aortas of this animal model. PMID:15451796

  10. Receptor-selective retinoids inhibit the growth of normal and malignant breast cells by inducing G1 cell cycle blockade.

    PubMed

    Wu, Kendall; DuPré, Elizabeth; Kim, Heetae; Tin-U, Caesar K; Bissonnette, Reid P; Lamph, William W; Brown, Powel H

    2006-03-01

    Despite advances in treatment, breast cancer continues to be the second leading cause of cancer mortality in women. Statistics suggest that while focus on treatment should continue, chemopreventive approaches should also be pursued. Previous studies have demonstrated that naturally occurring retinoids such as 9-cis retinoic acid (9cRA) can prevent breast cancer in animal models. However, these studies have also shown that these compounds are too toxic for general use. Work from our laboratory showed that an RXR-selective retinoid LGD1069 prevented tumor development in animal models of cancer with reduced toxicity as compared to an RAR-selective retinoid TTNPB. In the present study, we investigated the mechanisms by which receptor-selective retinoids inhibit the growth of normal and malignant breast cells. Our results demonstrate that the synthetic retinoids tested are as effective as 9cRA in suppressing the growth of normal human mammary epithelial cells (HMECs) and estrogen receptor-positive (ER-positive) breast cancer cells. Although the receptor-selective retinoids induce minimal amounts of apoptosis in T47D breast cancer cells, the predominant factor that leads to growth arrest is G1 cell cycle blockade. Our data indicate that this blockade results from the downregulation of Cyclin D1 and Cyclin D3, which in turn causes Rb hypophosphorylation. Non-toxic retinoids that are potent inducers of cell cycle arrest may be particularly useful for the prevention of breast cancer.

  11. Habituation deficits induced by metabotropic glutamate receptors 2/3 receptor blockade in mice: reversal by antipsychotic drugs.

    PubMed

    Bespalov, Anton; Jongen-Rêlo, Ana-Lucia; van Gaalen, Marcel; Harich, Silke; Schoemaker, Hans; Gross, Gerhard

    2007-02-01

    Cortical metabotropic glutamate receptors (mGluRs) seem to be involved in habituation of simple stimulus-bound behaviors (e.g., habituation to acoustic startle or odor-elicited orienting response). Habituation deficits may contribute to the cognitive symptoms of schizophrenia. In the present study, male NMRI mice were injected with mGluR2/3 antagonist 2S-2-amino-2-(1S,2S-2-carboxycyclopropyl-1-yl)-3-(xanth-9-yl)propanoic acid (LY-341495) 30 min before being placed into novel arenas for automatic motor activity recording (2-h sessions). Administration of LY-341495 (1-10 mg/kg s.c.) dose-dependently prevented the habituation of the locomotor activity. Effects of LY-341495 (10 mg/kg) were fully and dose-dependently reversed by i.p. administration of haloperidol (0.03-0.3 mg/kg), clozapine (1-10 mg/kg), risperidone (0.01-0.1 mg/kg), olanzapine (0.3-3 mg/kg), aripiprazole (1-10 mg/kg), and sulpiride (3-30 mg/kg), each of which was given 15 min before the test. Effects of antipsychotic drugs were observed at the dose levels that did not affect spontaneous motor activity. LY-341495-induced delayed hyperactivity was also partially attenuated by lithium (50-200 mg/kg), amisulpride (1-10 mg/kg), and the selective dopamine D3 antagonist trans-N-[4-[2-(6-cyano-1,2,3,4-tetrahydroisoquinolin-2-yl)ethyl]cyclohexyl]-4-quinolinecarboxamide (SB-277011A; 3-30 mg/kg). Application of diazepam, imipramine, or several agonists and/or antagonists acting at various receptors that are thought to be relevant for antipsychotic treatment [e.g., 5-hydroxytryptamine (5-HT)(2A), 5-HT(3), and 5-HT(6) antagonists; 5-HT(1A) agonist; D4 antagonist; CB1 antagonist; ampakines; and glycine transporter inhibitor) had no appreciable effects. Thus, behavioral deficits induced by mGluR2/3 blockade (such as delayed motor hyperactivity) are selectively reversed by clinically used antipsychotic drugs.

  12. Chronic blockade of cannabinoid CB2 receptors induces anxiolytic-like actions associated with alterations in GABAA receptors

    PubMed Central

    García-Gutiérrez, María S; García-Bueno, Borja; Zoppi, Silvia; Leza, Juan C; Manzanares, Jorge

    2012-01-01

    BACKGROUND AND PURPOSE The aim of this study was to explore the effects of CB2 receptor agonist and antagonist in the regulation of anxiety-like behaviours. EXPERIMENTAL APPROACHES Effects of acute and chronic treatment with the CB2 receptor agonist JWH133 and CB2 receptor antagonist AM630 were evaluated in the light-dark box (LDB) and elevated plus maze (EPM) tests in Swiss ICR mice. CB2 receptor, GABAAα2 and GABAAγ2 gene and protein expression in the cortex and amygdala of mice chronically treated with JWH133 or AM630 were examined by RT-PCR and Western blot. Effects of chronic AM630 treatment were evaluated in spontaneously anxious DBA/2 mice in LDB. KEY RESULTS Acute JWH133 treatment failed to produce any effect. Acute AM630 treatment increased anxiety and was blocked by pre-treatment with JWH133. Chronic JWH133 treatment increased anxiety-like behaviour whereas chronic AM630 treatment was anxiolytic in LDB and EPM tests. Chronic AM630 treatment increased gene and reduced protein expression of CB2 receptors, GABAAα2 and GABAAγ2 in cortex and amygdala. Chronic JWH133 treatment resulted in opposite gene and protein alterations. In addition, chronic AM630 administration decreased the anxiety of DBA/2 mice in the LDB test. CONCLUSIONS AND IMPLICATIONS The opposing behavioural and molecular changes observed after chronic treatment with AM630 or JWH133 support the key role of CB2 receptors in the regulation of anxiety. Indeed, the efficacy of AM630 in reducing the anxiety of the spontaneously anxious DBA/2 strain of mice strengthens the potential of the CB2 receptor as a new target in the treatment of anxiety-related disorders. PMID:21838753

  13. Enduring abolishment of remote but not recent expression of conditioned fear by the blockade of calcium-permeable AMPA receptors before extinction training.

    PubMed

    Zelena, Dóra; Mikics, Éva; Balázsfi, Diána; Varga, János; Klausz, Barbara; Urbán, Eszter; Sipos, Eszter; Biró, László; Miskolczi, Christina; Kovács, Krisztina; Ferenczi, Szilamér; Haller, József

    2016-06-01

    Calcium-permeable (GluA2 subunit-free) AMPA receptors (CP-AMPAR) play prominent roles in fear extinction; however, no blockers of these receptors were studied in tests relevant to extinction learning so far. The CP-AMPAR antagonist IEM-1460 was administered once before extinction trainings, which were started either 1 or 28 days after fear conditioning (FC). We used a mild extinction protocol that durably decreased but did not abolish conditioned fear. The messenger RNA (mRNA) expression of GluA1 and GluA2 subunits were investigated at both time points in the ventromedial prefrontal cortex (vmPFC) and amygdala. IEM-1460 transiently facilitated extinction 1 day after conditioning, but learned fear spontaneously recovered 4 weeks later. When the extinction protocol was applied 28 days after training, IEM-1460 enhanced extinction memory, moreover abolished conditioned fear for at least a month. The expression of GluA1 and GluA2 mRNAs was increased at both time points in the vmPFC. In the basolateral and central amygdala, the GluA1/GluA2 mRNA ratio increased, suggesting a shift towards the preponderance of GluA1 over GluA2 expression. AMPAR blockade lastingly enhanced the extinction of remote but not recent fear memories. Time-dependent changes in AMPA receptor subunit mRNA expression may explain the differential effects of CP-AMPAR blockade on recent and remote conditioned fear, further supporting the notion that the mechanisms maintaining learned fear change over time. Our findings suggest clinical implications for CP-AMPAR blockers, particularly for acquired anxieties (e.g., post-traumatic stress disorder) which have a slow onset and are durable.

  14. Interleukin 1 (IL-1) gene expression, synthesis, and effect of specific IL-1 receptor blockade in rabbit immune complex colitis.

    PubMed Central

    Cominelli, F; Nast, C C; Clark, B D; Schindler, R; Lierena, R; Eysselein, V E; Thompson, R C; Dinarello, C A

    1990-01-01

    Interleukin 1 (IL-1) may be a key mediator of inflammation and tissue damage in inflammatory bowel disease (IBD). In rabbits with immune complex-induced colitis, IL-1 alpha and beta mRNA levels were detectable at 4 h, peaked at 12 but were absent at 96 h after the induction of colitis. Colonic IL-1 tissue levels were measured by specific radioimmunoassays. IL-1 alpha was significantly elevated at 4 h (9.4 +/- 1.5 ng/g colon), progressively increased at 48 h (31 +/- 5.8 ng/g) and then decreased by 96 h (11.5 +/- 3.4 ng/g). IL-1 beta levels were 2.0 +/- 0.5 ng/g colon at 4 h, 5.0 +/- 1.6 ng/g at 48 h and undetectable by 96 h. By comparison, colonic levels of PGE2 and LTB4 were unchanged during the first 12 h and did not become elevated until 24 h. IL-1 alpha levels were highly correlated with inflammation (r = 0.885, P less than 0.0001), edema (r = 0.789, P less than 0.0001) and necrosis (r = 0.752, P less than 0.0005). Treatment with a specific IL-1 receptor antagonist (IL-1 ra) before and during the first 33 h after the administration of immune complexes markedly reduced inflammatory cell infiltration index (from 3.2 +/- 0.4 to 1.4 +/- 0.3, P less than 0.02), edema (from 2.2 +/- 0.4 to 0.6 +/- 0.3, P less than 0.01) and necrosis (from 43 +/- 10% to 6.6 +/- 3.2%, P less than 0.03) compared to vehicle-matched colitis animals. These studies demonstrate that (a) IL-1 gene expression and synthesis occur early in the course of immune complex-induced colitis; (b) are significantly elevated for 12 h before the appearance of PGE2 and LTB4; (c) tissue levels of IL-1 correlate with the degree of tissue inflammation and; (d) specific blockade of IL-1 receptors reduces the inflammatory responses associated with experimental colitis. Images PMID:2168444

  15. Prostacyclin and thromboxane A2 production in nitric oxide-deficient hypertension in vivo. Effects of high calcium diet and angiotensin receptor blockade.

    PubMed

    Alanko, Juha; Jolma, Pasi; Kööbi, Peeter; Riutta, Asko; Kalliovalkama, Jarkko; Tolvanen, Jari Petteri; Pörsti, Ilkka

    2003-11-01

    The effects of chronic nitric oxide deficiency on prostacyclin and thromboxane A(2) production in vivo are unknown. Therefore, we treated rats with N(G)-nitro-L-arginine methyl ester (L-NAME), and used losartan and high calcium diet as antihypertensive treatments. Forty eight Wistar rats were divided into six groups: control; losartan (20mgkg(-1)day(-1)); high calcium diet (dietary calcium elevated from 1.1% to 3%); L-NAME (20mgkg(-1)day(-1)); losartan+L-NAME and high calcium diet+L-NAME. Prostacyclin and thromboxane A(2) production were measured after eight weeks as urinary 2,3-dinor-6-keto-PGF(1alpha) and 11-dehydro-TXB(2), respectively. Both the high calcium diet and losartan reduced blood pressure in L-NAME hypertension. Chronic nitric oxide deficiency did not modulate prostacyclin production but it nearly doubled thromboxane A(2) production in vivo. This effect was not influenced by lowering of blood pressure by blockade of angiotensin II type 1 receptors. Independent of the level of blood pressure and blockade of nitric oxide synthesis the high calcium diet decreased prostacyclin production by one third and increased thromboxane A(2) production almost two-fold in vivo.

  16. NEUROTROPHIN RECEPTOR BLOCKADE ATTENUATES DIESEL EXHAUST PARTICULATE MATTER (DEP) ENHANCEMENT OF ALLERGIC RESPONSES

    EPA Science Inventory

    ABSTRACT BODY:
    Recent investigations have linked neurotrophins including NGF, NT-3, and BDNF to allergic airways diseases. Antibody blockade of NGF attenuates airway resistance associated with allergic airway responses in mice. Mice administered an antibody against the low aff...

  17. NEUROTROPHIN RECEPTOR BLOCKADE ATTENUATES DIESEL EXHAUST PARTICULATE MATTER (DEP) ENHANCEMENT OF ALLERGIC RESPONSES

    EPA Science Inventory

    ABSTRACT BODY:
    Recent investigations have linked neurotrophins including NGF, NT-3, and BDNF to allergic airways diseases. Antibody blockade of NGF attenuates airway resistance associated with allergic airway responses in mice. Mice administered an antibody against the low aff...

  18. Angiotensin II receptor blockade promotes repair of skeletal muscle through down-regulation of aging-promoting C1q expression

    PubMed Central

    Yabumoto, Chizuru; Akazawa, Hiroshi; Yamamoto, Rie; Yano, Masamichi; Kudo-Sakamoto, Yoko; Sumida, Tomokazu; Kamo, Takehiro; Yagi, Hiroki; Shimizu, Yu; Saga-Kamo, Akiko; Naito, Atsuhiko T.; Oka, Toru; Lee, Jong-Kook; Suzuki, Jun-ichi; Sakata, Yasushi; Uejima, Etsuko; Komuro, Issei

    2015-01-01

    Disruption of angiotensin II type 1 (AT1) receptor prolonged life span in mice. Since aging-related decline in skeletal muscle function was retarded in Atgr1a−/− mice, we examined the role of AT1 receptor in muscle regeneration after injury. Administration of AT1 receptor blocker irbesartan increased the size of regenerating myofibers, decreased fibrosis, and enhanced functional muscle recovery after cryoinjury. We recently reported that complement C1q, secreted by macrophages, activated Wnt/β-catenin signaling and promoted aging-related decline in regenerative capacity of skeletal muscle. Notably, irbesartan induced M2 polarization of macrophages, but reduced C1q expression in cryoinjured muscles and in cultured macrophage cells. Irbesartan inhibited up-regulation of Axin2, a downstream gene of Wnt/β-catenin pathway, in cryoinjured muscles. In addition, topical administration of C1q reversed beneficial effects of irbesartan on skeletal muscle regeneration after injury. These results suggest that AT1 receptor blockade improves muscle repair and regeneration through down-regulation of the aging-promoting C1q-Wnt/β-catenin signaling pathway. PMID:26571361

  19. Effect of chronic blockade of angiotensin II-receptor subtypes on aortic compliance in rats with myocardial infarction.

    PubMed

    Ceiler, D L; Nelissen-Vrancken, H J; De Mey, J G; Smits, J F

    1998-04-01

    This study was undertaken to investigate changes in aortic geometry and compliance after long-term blockade of angiotensin receptors type 1 (AT1) and AT2 receptors under basal conditions and after myocardial infarction (MI). Sham-operated (sham) or MI rats received either no treatment, AT1 antagonist GR138950C (GR; 2 mg/kg/day i.v.), or AT2 antagonist PD123319 (PD; 3 mg/kg/day s.c.). After 3 weeks, mean arterial blood pressure (MAP) was measured. Thoracic aorta diastolic diameter (D[dia]), compliance coefficient (CC), and distensibility coefficient (DC) were determined noninvasively in anesthetized rats by using ultrasound and wall tracking. After the rats were killed, histologic measurements were made on aortic cross sections. In sham rats, MAP was reduced by GR treatment (76 +/- 6 vs. 106 +/- 5 mm Hg), but not by PD. D(dia) was reduced in both GR-treated (1.74 +/- 0.08 vs. 2.09 +/- 0.05 mm) and PD-treated (1.83 +/- 0.05 vs. 2.09 +/- 0.05 mm) sham rats. CC and DC were not modified by either treatment. Although media cross-sectional area was not affected by either GR or PD treatment in sham rats, media thickness and media/lumen ratio were increased in both cases. Induction of MI had no effect on aortic structure, geometry, or mechanics; however, treatment with either GR or PD improved DC versus untreated MI rats. We conclude that AT1 and AT2 receptors are involved in angiotensin II-mediated effects on aortic geometry and mechanics under both basal conditions and after MI. Whereas blockade of AT1 receptors most likely influences vascular properties through a depressor mechanism, AT2 receptors induce pressure-independent remodeling.

  20. Selective blockade of 5-HT7 receptors facilitates attentional set-shifting in stressed and control rats.

    PubMed

    Nikiforuk, Agnieszka

    2012-01-01

    Preclinical data demonstrate that the selective blockade of 5-HT7 receptors produces antidepressant-like behavioural effects. Although the involvement of 5-HT7 receptors in cognitive processes has been previously suggested, little is known about their role in the prefrontal cortex (PFC)-dependent processes that may be impaired in stress-related states. According to our previous study, repeated restraint stress induces the long-lasting cognitive impairment in a rat model of PFC-dependent attentional set-shifting task (ASST). Therefore, the first aim of the present experiments was to examine the impact of the selective 5-HT7 receptor antagonist, SB-269970, on ASST performance of stressed and control rats. Since the selective blockade of 5-HT7 receptors has been previously demonstrated to enhance the behavioural effects of antidepressants, the second goal was to examine the impact of the joint administration of inactive doses of SB-269970 and escitalopram in the ASST. SB-269970 (0.3 and 1mg/kg) given to stressed rats 30min before testing reversed the restraint-induced impairment of the extra-dimensional (ED) set-shifting ability. Additionally, SB-269970 (1mg/kg) also improved ED performance of the unstressed control group. Moreover, SB-269970, given at an inactive dose, enhanced the pro-cognitive efficacy of escitalopram. In conclusion, these results highlight the possibility that 5-HT7 receptor antagonism may represent a useful pharmacological approach in the treatment of frontal-like cognitive disturbances in stress-related psychiatric disorders.

  1. A peripherally administered, centrally acting angiotensin II AT2 antagonist selectively increases brain AT1 receptors and decreases brain tyrosine hydroxylase transcription, pituitary vasopressin and ACTH

    PubMed Central

    Macova, Miroslava; Pavel, Jaroslav; Saavedra, Juan M.

    2009-01-01

    The physiological actions of brain Angiotensin II AT2 receptors and their relationship to Angiotensin II AT1 receptors remain controversial. To further clarify their role, we determined to what extent systemic administration of an AT2 receptor antagonist affected AT2 receptor binding within the brain and the expression of AT1 receptors. For this purpose, we subcutaneously administered the AT2 receptor antagonist PD123319 (1 mg/kg/day) to adult male rats for two weeks via osmotic minipumps. We also studied the content of pituitary adrenocorticotropic hormone and vasopressin, representative of hypothalamic–pituitary–adrenal axis activation, and the tyrosine hydroxylase gene expression in the locus coeruleus as a measure of central norepinephrine function. We found significant decreases in AT2 receptor binding in brain areas inside the blood brain barrier, the inferior olive and the locus coeruleus. AT2 receptor blockade increased AT1 receptor binding and mRNA expression not only in the subfornical organ and the median eminence, situated outside the blood brain barrier, but also in the hypothalamic paraventricular nucleus, located inside the blood brain barrier. These changes paralleled decreased expression of tyrosine hydroxylase mRNA in the locus coeruleus and decreased pituitary adrenocorticotropic and vasopressin content. Our results demonstrate that sustained peripheral administration of an AT2 antagonist decreases binding to brain AT2 receptors, indicating that this drug is a useful tool for the study of their central role. AT2 receptor activity inhibition up-regulates AT1 receptor expression in specific brain areas. Blockade of brain AT2 receptors is compatible with enhanced hypothalamic–pituitary–adrenal axis and decreased central sympathetic system activity. PMID:19038235

  2. Receptor-mediated control of regulatory volume decrease (RVD) and apoptotic volume decrease (AVD)

    PubMed Central

    Okada, Yasunobu; Maeno, Emi; Shimizu, Takahiro; Dezaki, Katsuya; Wang, Jun; Morishima, Shigeru

    2001-01-01

    A fundamental property of animal cells is the ability to regulate their own cell volume. Even under hypotonic stress imposed by either decreased extracellular or increased intracellular osmolarity, the cells can re-adjust their volume after transient osmotic swelling by a mechanism known as regulatory volume decrease (RVD). In most cell types, RVD is accomplished mainly by KCl efflux induced by parallel activation of K+ and Cl− channels. We have studied the molecular mechanism of RVD in a human epithelial cell line (Intestine 407). Osmotic swelling results in a significant increase in the cytosolic Ca2+ concentration and thereby activates intermediate-conductance Ca2+-dependent K+ (IK) channels. Osmotic swelling also induces ATP release from the cells to the extracellular compartment. Released ATP stimulates purinergic ATP (P2Y2) receptors, thereby inducing phospholipase C-mediated Ca2+ mobilization. Thus, RVD is facilitated by stimulation of P2Y2 receptors due to augmentation of IK channels. In contrast, stimulation of another G protein-coupled Ca2+-sensing receptor (CaR) enhances the activity of volume-sensitive outwardly rectifying Cl− channels, thereby facilitating RVD. Therefore, it is possible that Ca2+ efflux stimulated by swelling-induced and P2Y2 receptor-mediated intracellular Ca2+ mobilization activates the CaR, thereby secondarily upregulating the volume-regulatory Cl− conductance. On the other hand, the initial process towards apoptotic cell death is coupled to normotonic cell shrinkage, called apoptotic volume decrease (AVD). Stimulation of death receptors, such as TNFα receptor and Fas, induces AVD and thereafter biochemical apoptotic events in human lymphoid (U937), human epithelial (HeLa), mouse neuroblastoma × rat glioma hybrid (NG108-15) and rat phaeochromocytoma (PC12) cells. In those cells exhibiting AVD, facilitation of RVD is always observed. Both AVD induction and RVD facilitation as well as succeeding apoptotic events can be

  3. Receptor-mediated control of regulatory volume decrease (RVD) and apoptotic volume decrease (AVD).

    PubMed

    Okada, Y; Maeno, E; Shimizu, T; Dezaki, K; Wang, J; Morishima, S

    2001-04-01

    A fundamental property of animal cells is the ability to regulate their own cell volume. Even under hypotonic stress imposed by either decreased extracellular or increased intracellular osmolarity, the cells can re-adjust their volume after transient osmotic swelling by a mechanism known as regulatory volume decrease (RVD). In most cell types, RVD is accomplished mainly by KCl efflux induced by parallel activation of K+ and Cl- channels. We have studied the molecular mechanism of RVD in a human epithelial cell line (Intestine 407). Osmotic swelling results in a significant increase in the cytosolic Ca2+ concentration and thereby activates intermediate-conductance Ca2+-dependent K+ (IK) channels. Osmotic swelling also induces ATP release from the cells to the extracellular compartment. Released ATP stimulates purinergic ATP (P2Y2) receptors, thereby inducing phospholipase C-mediated Ca2+ mobilization. Thus, RVD is facilitated by stimulation of P2Y2 receptors due to augmentation of IK channels. In contrast, stimulation of another G protein-coupled Ca2+-sensing receptor (CaR) enhances the activity of volume-sensitive outwardly rectifying Cl- channels, thereby facilitating RVD. Therefore, it is possible that Ca2+ efflux stimulated by swelling-induced and P2Y2 receptor-mediated intracellular Ca2+ mobilization activates the CaR, thereby secondarily upregulating the volume-regulatory Cl- conductance. On the other hand, the initial process towards apoptotic cell death is coupled to normotonic cell shrinkage, called apoptotic volume decrease (AVD). Stimulation of death receptors, such as TNF receptor and Fas, induces AVD and thereafter biochemical apoptotic events in human lymphoid (U937), human epithelial (HeLa), mouse neuroblastoma x rat glioma hybrid (NG108-15) and rat phaeochromocytoma (PC12) cells. In those cells exhibiting AVD, facilitation of RVD is always observed. Both AVD induction and RVD facilitation as well as succeeding apoptotic events can be abolished by

  4. Endothelin Receptor Blockade Ameliorates Vascular Fragility in Endothelial Cell–Specific Fli-1–Knockout Mice by Increasing Fli-1 DNA Binding Ability

    PubMed Central

    Akamata, Kaname; Asano, Yoshihide; Yamashita, Takashi; Noda, Shinji; Taniguchi, Takashi; Takahashi, Takehiro; Ichimura, Yohei; Toyama, Tetsuo; Trojanowska, Maria; Sato, Shinichi

    2016-01-01

    Objective It is generally accepted that blockade of endothelin receptors has potentially beneficial effects on vasculopathy associated with systemic sclerosis (SSc). The aim of this study was to clarify the molecular mechanism underlying these effects using endothelial cell–specific Fli-1–knockout (Fli-1 ECKO) mice, an animal model of SSc vasculopathy. Methods Levels of messenger RNA for target genes and the expression and phosphorylation levels of target proteins were determined in human and murine dermal microvascular endothelial cells by real-time quantitative reverse transcription–polymerase chain reaction and immunoblotting, respectively. The binding of Fli-1 to the target gene promoters was evaluated using chromatin immunoprecipitation. Expression levels of Fli-1 and α-smooth muscle actin in murine skin were evaluated using immunohistochemistry. Vascular structure and permeability were evaluated in mice injected with fluorescein isothiocyanate–dextran and Evans blue dye, respectively. Results In human dermal microvascular endothelial cells, endothelin 1 induced phosphorylation of Fli-1 at Thr312 through the sequential activation of c-Abl and protein kinase Cδ, leading to a decrease in Fli-1 protein levels as well as a decrease in binding of Fli-1 to the target gene promoters, whereas bosentan treatment reversed those effects. In Fli-1 ECKO mice, 4 weeks of treatment with bosentan increased endothelial Fli-1 expression, resulting in vascular stabilization and the restoration of impaired leaky vessels. Conclusion The vascular fragility of Fli-1 ECKO mice was improved by bosentan through the normalization of Fli-1 protein levels and activity in endothelial cells, which may explain, in part, the mechanism underlying the beneficial effects of endothelin receptor blockade on SSc vasculopathy. PMID:25707716

  5. Endothelin receptor blockade ameliorates renal injury by inhibition of RhoA/Rho-kinase signalling in deoxycorticosterone acetate-salt hypertensive rats.

    PubMed

    Lee, Tsung-Ming; Chung, Tun-Hui; Lin, Shinn-Zong; Chang, Nen-Chung

    2014-04-01

    Excessive production of fibrosis is a feature of hypertension-induced renal injury. Activation of RhoA/Rho-kinase (ROCK) axis has been shown in deoxycorticosterone acetate (DOCA)-salt hypertensive rats. We assessed whether selective endothelin receptor blockers can attenuate renal fibrosis by inhibiting RhoA/ROCK axis in DOCA-salt rats. At 4 weeks after the start of DOCA-salt treatment and uninephrectomization, male Wistar rats were randomized into three groups for 4 weeks: vehicle, ABT-627 (endothelin-A receptor inhibitor) and A192621 (endothelin-B receptor inhibitor). DOCA-salt was characterized by increased blood pressure, decreased renal function, increased proteinuria, increased glomerulosclerosis and tubulointerstitial fibrosis with myofibroblast accumulation, increased renal endothelin-1 levels and RhoA activity along with increased expression of connective tissue growth factor at both mRNA and protein levels as compared with uninephrectomized control male Wistar rats. Treatment with a selective mineralocorticoid receptor antagonist, eplerenone, ameliorated proteinuria. Impaired renal function and histological changes were overcome by treatment with ABT-627, but not with A192621. The beneficial effects of bosentan, a nonspecific endothelin receptor blocker, on proteinuria, RhoA activity, and connective tissue growth factor levels were similar to ABT-627. Furthermore, in an isolated perfuse kidney, a RhoA inhibitor, C3 exoenzyme, and two ROCK inhibitors, fasudil and Y-27632, significantly attenuated connective tissue growth factor levels. These results indicate that DOCA-salt elevates renal endothelin-1 levels and RhoA activity via activation of mineralocorticoid receptor, resulting in renal fibrosis and proteinuria. Endothelin-A receptor blockade can attenuate DOCA-salt-induced renal fibrosis probably through the inhibition of RhoA/ROCK activity and connective tissue growth factor expression.

  6. Blockade of metabotropic glutamate receptor 5 activation inhibits mechanical hypersensitivity following abdominal surgery.

    PubMed

    Dolan, Sharron; Nolan, Andrea Mary

    2007-08-01

    This study used the metabotropic glutamate 5 (mGlu5) receptor subtype-selective antagonist 2-methyl-6-(phenylethynyl)pyridine (MPEP) to characterise the contribution of mGlu5 receptor activity to pain and hypersensitivity in an animal model of post-surgical pain. Adult female Wistar rats (200-250g) were anaesthetised with isoflurane (2%) and underwent a midline laparotomy with gentle manipulation of the viscera, and the effects of pre- (30min) or post- (5h) operative treatment with MPEP (1, 3 or 10mgkg(-1); i.p.) or drug-vehicle on hindpaw withdrawal latency (in seconds) to thermal stimulation (Hargreave's Test) and response threshold (in grams) to mechanical stimulation (using a dynamic plantar aesthesiometer) were measured. Animals that underwent surgery displayed significant hypersensitivity to mechanical stimulation of the hindpaws. Hypersensitivity was maximum at 6h post-surgery (44.5+/-2.4% decrease; p<0.01 vs. anaesthesia only controls) and persisted for 48h. Surgery had no effect on thermal withdrawal latency. Both pre-operative and post-operative administration of 10mgkg(-1)MPEP blocked mechanical hypersensitivity induced by surgery (p<0.01 vs. vehicle treatment). MPEP had no effect on acute nociceptive thresholds in naïve animals. These data suggest that activity at mGlu5 receptors contributes to development of pain and hypersensitivity following surgery.

  7. Platelet peripheral benzodiazepine receptors are decreased in Parkinson's disease

    SciTech Connect

    Bonuccelli, U.; Nuti, A.; Del Dotto, P.; Piccini, P.; Martini, C.; Giannacccini, G.; Lucacchini, A.; Muratorio, A. )

    1991-01-01

    Peripheral benzodiazepine (BDZ) receptors are located in a variety of tissues, including platelets, in the nuclear and/or mitochondrial membranes. The authors studied the density of peripheral BDZ receptors in platelets of 10 de novo Parkinson's disease (PD) patients, 18 PD patients treated with a levodopa/carbidopa combination, and in 15 healthy subjects matched for sex and age. The binding assay was conducted using ({sup 3}H)PK 11195, a specific ligand for peripheral BDZ receptors. A significant decrease in the density of ({sup 3}H)PK 11195 binding sites has been observed in PD patients with respect to controls but not between de novo and treated PD patients. No correlation has been found between the decrease in density of ({sup 3}H)PK 11195 binding sites in platelets and either the duration or severity of PD. Peripheral BDZ receptors are implicated in the regulation of mitochondrial respiratory function. Thus, their decrease in PD might parallel the abnormalities in mitochondrial function recently found in this neurologic disease.

  8. Effect of Selective Mineralocorticoid Receptor Blockade on Flow-Mediated Dilation and Insulin Resistance in Older Adults with Metabolic Syndrome.

    PubMed

    Hwang, Moon-Hyon; Yoo, Jeung-Ki; Luttrell, Meredith; Meade, Thomas H; English, Mark; Christou, Demetra D

    2015-10-01

    The prevalence of metabolic syndrome is especially high in older adults. Metabolic syndrome is associated with impaired vascular endothelial function, insulin resistance, and increased risk for cardiovascular disease but the underlying mechanisms are not fully elucidated. Plasma aldosterone is independently associated with metabolic syndrome and is linked to endothelial dysfunction and insulin resistance. Thus, we hypothesized that mineralocorticoid receptor (MR) blockade would improve flow-mediated dilation and insulin resistance in older adults with metabolic syndrome. To test this hypothesis, we conducted a balanced, randomized, double-blind, placebo-controlled, crossover study using selective MR blockade (eplerenone; 100 mg/day) for 1 month with 1 month washout in older adults with metabolic syndrome (62.6 ± 3.2 yrs; mean ± standard error). We evaluated brachial artery flow-mediated dilation (ultrasonography), oxidative stress (oxidized low-density lipoproteins and F2-isoprostanes) and insulin resistance (homeostatic model assessment). In response to MR blockade, flow-mediated dilation (5.37 ± 0.85 vs. 5.98 ± 1.29%; placebo vs. eplerenone; P = 0.4), oxidized low-density lipoproteins (51.6 ± 11.5 vs. 56.1 ± 10.9 U/L; P = 0.6), and F2-isoprostanes (0.07 ± 0.02 vs. 0.06 ± 0.01 pg/mL; P = 0.3) did not improve. Insulin resistance also did not change following MR blockade (1.04 ± 0.26 vs. 1.38 ± 0.50; P = 0.6). However, MR blockade resulted in a large reduction (10 mmHg) in systolic blood pressure (140 ± 6 vs. 130 ± 6 mmHg; P = 0.02), with no significant change in diastolic blood pressure (81 ± 3 vs. 75 ± 2 mmHg; P = 0.2). Our data do not support a contributing role for MRs in endothelial dysfunction and insulin resistance in older adults with metabolic syndrome. However, our findings suggest MR activation is an important contributor to systolic hypertension in

  9. Effects of dopamine D1 receptor activation and blockade on dopamine and noradrenaline levels in the rat brain.

    PubMed

    Avila-Luna, Alberto; Verduzco-Mendoza, Antonio; Bueno-Nava, Antonio

    2016-01-26

    The noradrenergic and dopaminergic systems are associated with the motor system and have anatomical and functional connections that have not yet been studied. The present study aimed to examine the specific role of D1 receptors (D1Rs) on noradrenergic and dopaminergic responses in the rat brain. Male Wistar rats were assigned to eight groups to receive systemic injection of a D1R agonist (SKF-38393) at 0, 1, 5 or 10mg/kg or injection of a D1R antagonist (SCH-23390) at 0, 0.25, 0.5 or 1mg/kg. Dopamine (DA) and noradrenaline (NA) levels were measured using high-performance liquid chromatography. Injection of SKF-38393 alone at 1, 5 and 10mg/kg did not alter DA levels in the midbrain, cerebral cortex or pons, while it significantly increased these levels in the striatum (at 1 and 10mg/kg), hippocampus (at 1mg/kg) and cerebellum (at 1 and 5mg/kg). Administration of SKF-38393 at 1, 5, and 10mg/kg decreased the NA levels in the midbrain, pons, hippocampus (except at 1mg/kg) and cortex (except at 5mg/kg), whereas the opposite effect was observed in the striatum. SCH-23390 decreased the DA levels in the cortex (at 0.25 and 0.5mg/kg) and pons (at 0.5mg/kg). In contrast, 0.25, 0.5 and 1mg/kg SCH-23390 increased the DA levels in the cerebellum, whereas no differences from the control levels were observed for the DA levels in the striatum, midbrain and hippocampus. SCH-23390 at 0.5 and 1mg/kg increased the NA levels in the striatum. In contrast, the midbrain, hippocampus, cortex, pons and cerebellum did not exhibit altered NA levels. Our results demonstrate that the activation of D1Rs modulates the response of the noradrenergic system in nearly all of the investigated brain structures; thus, the blockade of D1Rs attenuates the effects induced by D1R activation.

  10. GluN2B-containing NMDA receptors blockade rescues bidirectional synaptic plasticity in the bed nucleus of the stria terminalis of cocaine self-administering rats.

    PubMed

    deBacker, Julian; Hawken, Emily R; Normandeau, Catherine P; Jones, Andrea A; Di Prospero, Cynthia; Mechefske, Elysia; Gardner Gregory, James; Hayton, Scott J; Dumont, Éric C

    2015-01-01

    Drugs of abuse have detrimental effects on homeostatic synaptic plasticity in the motivational brain network. Bidirectional plasticity at excitatory synapses helps keep neural circuits within a functional range to allow for behavioral flexibility. Therefore, impaired bidirectional plasticity of excitatory synapses may contribute to the behavioral hallmarks of addiction, yet this relationship remains unclear. Here we tracked excitatory synaptic strength in the oval bed nucleus of the stria terminalis (ovBNST) using whole-cell voltage-clamp recordings in brain slices from rats self-administering sucrose or cocaine. In the cocaine group, we measured both a persistent increase in AMPA to NMDA ratio (A:N) and slow decay time of NMDA currents throughout the self-administration period and after withdrawal from cocaine. In contrast, the sucrose group exhibited an early increase in A:N ratios (acquisition) that returned toward baseline values with continued self-administration (maintenance) and after withdrawal. The sucrose rats also displayed a decrease in NMDA current decay time with continued self-administration (maintenance), which normalized after withdrawal. Cocaine self-administering rats exhibited impairment in NMDA-dependent long-term depression (LTD) that could be rescued by GluN2B-containing NMDA receptor blockade. Sucrose self-administering rats demonstrated no impairment in NMDA-dependent LTD. During the maintenance period of self-administration, in vivo (daily intraperitoneally for 5 days) pharmacologic blockade of GluN2B-containing NMDA receptors did not reduce lever pressing for cocaine. However, in vivo GluN2B blockade did normalize A:N ratios in cocaine self-administrating rats, and dissociated the magnitude of ovBNST A:N ratios from drug-seeking behavior after protracted withdrawal. Altogether, our data demonstrate when and how bidirectional plasticity at ovBNST excitatory synapses becomes dysfunctional with cocaine self-administration and that NMDA

  11. Chronic and acute adenosine A2A receptor blockade prevents long-term episodic memory disruption caused by acute cannabinoid CB1 receptor activation.

    PubMed

    Mouro, Francisco M; Batalha, Vânia L; Ferreira, Diana G; Coelho, Joana E; Baqi, Younis; Müller, Christa E; Lopes, Luísa V; Ribeiro, Joaquim A; Sebastião, Ana M

    2017-05-01

    Cannabinoid-mediated memory impairment is a concern in cannabinoid-based therapies. Caffeine exacerbates cannabinoid CB1 receptor (CB1R)-induced memory deficits through an adenosine A1 receptor-mediated mechanism. We now evaluated how chronic or acute blockade of adenosine A2A receptors (A2ARs) affects long-term episodic memory deficits induced by a single injection of a selective CB1R agonist. Long-term episodic memory was assessed by the novel object recognition (NOR) test. Mice received an intraperitoneal (i.p.) injection of the CB1/CB2 receptor agonist WIN 55,212-2 (1 mg/kg) immediately after the NOR training, being tested for novelty recognition 24 h later. Anxiety levels were assessed by the Elevated Plus Maze test, immediately after the NOR. Mice were also tested for exploratory behaviour at the Open Field. For chronic A2AR blockade, KW-6002 (istradefylline) (3 mg/kg/day) was administered orally for 30 days; acute blockade of A2ARs was assessed by i.p. injection of SCH 58261 (1 mg/kg) administered either together with WIN 55,212-2 or only 30 min before the NOR test phase. The involvement of CB1Rs was assessed by using the CB1R antagonist, AM251 (3 mg/kg, i.p.). WIN 55,212-2 caused a disruption in NOR, an action absent in mice also receiving AM251, KW-6002 or SCH 58261 during the encoding/consolidation phase; SCH 58251 was ineffective if present during retrieval only. No effects were detected in the Elevated Plus maze or Open Field Test. The finding that CB1R-mediated memory disruption is prevented by antagonism of adenosine A2ARs, highlights a possibility to prevent cognitive side effects when therapeutic application of CB1R drugs is desired.

  12. Blockade of 5-Ht3 receptors in the septal area increases Fos expression in selected brain areas.

    PubMed

    Urzedo-Rodrigues, Lilia S; Ferreira, Hilda S; Santana, Rejane Conceição; Luz, Carla Patrícia; Perrone, Camila F; Fregoneze, Josmara B

    2014-04-01

    Serotonin is widely distributed throughout the brain and is involved in a multiplicity of visceral, cognitive and behavioral responses. It has been previously shown that injections of different doses of ondansetron, a 5-HT3 receptor antagonist, into the medial septum/vertical limb of the diagonal band complex (MS/vDB) induce a hypertensive response in rats. On the other hand, administration of m-CPBG, a 5-HT3 agonist, into the MS/vDB inhibits the increase of blood pressure during restraint stress. However, it is unclear which neuronal circuitry is involved in these responses. The present study investigated Fos immunoreactive nuclei (Fos-IR) in different brain areas following the blockade of 5-HT3 receptors located in the MS/vDB in sham and in sinoaortic denervated (SAD) rats. Ondansetron injection into the MS/vDB increases Fos-IR in different brain areas including the limbic system (central amygdala and ventral part of the bed nucleus of the stria terminalis), hypothalamus (medial parvocellular parts of the paraventricular nucleus, anterodorsal preoptic area, dorsomedial hypothalamic nucleus), mesencephalon (ventrolateral periaqueductal gray region) and rhombencephalon (lateral parabrachial nucleus) in sham rats. Barodenervation results in higher Fos expression at the parvocellular and magnocellular part of the paraventricular nucleus, the lateral parabrachial nucleus, the central nucleus of amygdala, the locus coeruleus, the medial part of the nucleus of the solitary tract, the rostral ventrolateral medulla and the caudal ventrolateral medulla following 5-HT3receptor blockade in the MS/vDB. Based on the present results and previous data showing a hypertensive response to ondansetron injected into the MS/vDB, it is reasonable to suggest that 5-HT3receptors in the MS/vDB exert an inhibitory drive that may oscillate as a functional regulatory part of the complex central neuronal network participating in the control of blood pressure.

  13. CB1 cannabinoid receptor-mediated anandamide signalling reduces the defensive behaviour evoked through GABAA receptor blockade in the dorsomedial division of the ventromedial hypothalamus.

    PubMed

    Dos Anjos-Garcia, Tayllon; Ullah, Farhad; Falconi-Sobrinho, Luiz Luciano; Coimbra, Norberto Cysne

    2017-02-01

    The effects of cannabinoids in brain areas expressing cannabinoid receptors, such as hypothalamic nuclei, are not yet well known. Several studies have demonstrated the role of hypothalamic nuclei in the organisation of behavioural responses induced through innate fear and panic attacks. Panic-prone states are experimentally induced in laboratory animals through a reduction in the GABAergic activity. The aim of the present study was to examine panic-like elaborated defensive behaviour evoked by GABAA receptor blockade with bicuculline (BIC) in the dorsomedial division of the ventromedial hypothalamus (VMHdm). We also aimed to characterise the involvement of endocannabinoids and the CB1 cannabinoid receptor in the modulation of elaborated defence behavioural responses organised with the VMHdm. The guide-cannula was stereotaxicaly implanted in VMHdm and the animals were treated with anandamide (AEA) at different doses, and the effective dose was used after the pre-treatment with the CB1 receptor antagonist AM251, followed by GABAA receptor blockade in VMHdm. The results showed that the intra-hypothalamic administration of AEA at an intermediate dose (5 pmol) attenuated defence responses induced through the intra-VMHdm microinjection of bicuculline (40 ng). This effect, however, was inhibited when applied central microinjection of the CB1 receptor antagonist AM251 in the VMHdm. Moreover, AM251 potentiates de non-oriented escape induced by bicuculline, effect blocked by pre-treatment with the TRPV1 channel antagonist 6-I-CPS. These results indicate that AEA modulates the pro-aversive effects of intra-VMHdm-bicuculline treatment, recruiting CB1 cannabinoid receptors and the TRPV1 channel is involved in the AM251-related potentiation of bicuculline effects on non-oriented escape behaviour.

  14. Hyperglycemia of Diabetic Rats Decreased by a Glucagon Receptor Antagonist

    NASA Astrophysics Data System (ADS)

    Johnson, David G.; Ulichny Goebel, Camy; Hruby, Victor J.; Bregman, Marvin D.; Trivedi, Dev

    1982-02-01

    The glucagon analog [l-Nα-trinitrophenylhistidine, 12-homoarginine]-glucagon (THG) was examined for its ability to lower blood glucose concentrations in rats made diabetic with streptozotocin. In vitro, THG is a potent antagonist of glucagon activation of the hepatic adenylate cyclase assay system. Intravenous bolus injections of THG caused rapid decreases (20 to 35 percent) of short duration in blood glucose. Continuous infusion of low concentrations of the inhibitor led to larger sustained decreases in blood glucose (30 to 65 percent). These studies demonstrate that a glucagon receptor antagonist can substantially reduce blood glucose levels in diabetic animals without addition of exogenous insulin.

  15. Role of adiponectin in the metabolic effects of cannabinoid type 1 receptor blockade in mice with diet-induced obesity

    PubMed Central

    Godlewski, Grzegorz; Earley, Brian J.; Zhou, Liang; Jourdan, Tony; Szanda, Gergö; Cinar, Resat; Kunos, George

    2013-01-01

    The adipocyte-derived hormone adiponectin promotes fatty acid oxidation and improves insulin sensitivity and thus plays a key role in the regulation of lipid and glucose metabolism and energy homeostasis. Chronic cannabinoid type 1 (CB1) receptor blockade also increases lipid oxidation and improves insulin sensitivity in obese individuals or animals, resulting in reduced cardiometabolic risk. Chronic CB1 blockade reverses the obesity-related decline in serum adiponectin levels, which has been proposed to account for the metabolic effects of CB1 antagonists. Here, we investigated the metabolic actions of the CB1 inverse agonist rimonabant in high-fat diet (HFD)-induced obese adiponectin knockout (Adipo−/−) mice and their wild-type littermate controls (Adipo+/+). HFD-induced obesity and its hormonal/metabolic consequences were indistinguishable in the two strains. Daily treatment of obese mice with rimonabant for 7 days resulted in significant and comparable reductions in body weight, serum leptin, free fatty acid, cholesterol, and triglyceride levels in the two strains. Rimonabant treatment improved glucose homeostasis and insulin sensitivity to the same extent in Adipo+/+ and Adipo−/− mice, whereas it reversed the HFD-induced hepatic steatosis, fibrosis, and hepatocellular damage only in the former. The adiponectin-dependent, antisteatotic effect of rimonabant was mediated by reduced uptake and increased β-oxidation of fatty acids in the liver. We conclude that reversal of the HFD-induced hepatic steatosis and fibrosis by chronic CB1 blockade, but not the parallel reduction in adiposity and improved glycemic control, is mediated by adiponectin. PMID:24381003

  16. Full central neurokinin-1 receptor blockade is required for efficacy in depression: evidence from orvepitant clinical studies.

    PubMed

    Ratti, Emiliangelo; Bettica, Paolo; Alexander, Robert; Archer, Graeme; Carpenter, David; Evoniuk, Gary; Gomeni, Roberto; Lawson, Erica; Lopez, Monica; Millns, Helen; Rabiner, Eugenii A; Trist, David; Trower, Michael; Zamuner, Stefano; Krishnan, Ranga; Fava, Maurizio

    2013-05-01

    Full, persistent blockade of central neurokinin-1 (NK1) receptors may be a potential antidepressant mechanism. The selective NK1 antagonist orvepitant (GW823296) was used to test this hypothesis. A preliminary positron emission tomography study in eight male volunteers drove dose selection for two randomized six week studies in patients with major depressive disorder (MDD). Displacement of central [(11)C]GR205171 binding indicated that oral orvepitant doses of 30-60 mg/day provided >99% receptor occupancy for ≥24 h. Studies 733 and 833 randomized patients with MDD and 17-item Hamilton Depression Rating Scale (HAM-D)≥22 to double-blind treatment with orvepitant 30 mg/day, orvepitant 60 mg/day or placebo (1:1:1). Primary outcome measure was change from baseline in 17-item HAM-D total score at Week 6 analyzed using mixed models repeated measures. Study 733 (n=328) demonstrated efficacy on the primary endpoint (estimated drug-placebo differences of 30 mg: -2.41, 95% confidence interval (CI) (-4.50 to -0.31) p=0.0245; 60 mg: -2.86, 95% CI (-4.97 to -0.75) p=0.0082). Study 833 (n=345) did not show significance (estimated drug-placebo differences of 30 mg: -1.67, 95% CI (-3.73 to 0.39) p=0.1122; 60 mg: -0.76, 95% CI (-2.85 to 1.32) p=0.4713). The results support the hypothesis that full, long lasting blockade of central NK1 receptors may be an efficacious mechanism for the treatment of MDD.

  17. Effects of Adrenergic Receptor Activation and Blockade on the Systolic Preejection Period, Heart Rate, and Arterial Pressure in Man

    PubMed Central

    Harris, Willard S.; Schoenfeld, Clyde D.; Weissler, Arnold M.

    1967-01-01

    We have investigated the possibility that alterations in the duration of the systolic preejection period can be used to estimate adrenergic influences on the human left ventricle. The preejection period was determined from high speed, simultaneous recordings of the phonocardiogram, carotid pulse tracing, and electrocardiogram. The preejection period was shortened by isoproterenol, epinephrine, and moderate doses of norepinephrine—all of which activate beta adrenergic receptors—and by cedilanid-D. It was unaltered by changes in heart rate induced by atropine and right atrial electrical pacing. Beta adrenergic receptor blockade by propranolol abolished the shortening effects of the three catecholamines but did not inhibit that due to cedilanid-D. Vasoconstriction, both alpha adrenergic (epinephrine and norepinephrine after propranolol) and nonadrenergic (angiotensin), prolonged the preejection period. Most of the shortening of the preejection period by beta adrenergic receptor activating agents and cedilanid-D and all of the prolongation accompanying pharmacologic vasoconstriction occurred after the onset of the first heart sound, thereby excluding changes in electrical-mechanical delay as a major factor in the observed preejection period responses. Shortening of the preejection period by beta adrenergic activity induced with isoproterenol was dose-related. Increasing doses of propranolol produced parallel shifts to the right in the isoproterenol dose-response curve. In 37 normal resting subjects intravenous propranolol (10 mg) prolonged the preejection period an average of 10 (SE ± 1) msec. In six patients with psychogenic sinus tachycardia and a patient with a pheochromocytoma the presence of excessive beta adrenergic influences on the left ventricle was demonstrated by the finding of an initially short preejection period which responded with an abnormally great prolongation to beta adrenergic receptor blockade. Images PMID:4294053

  18. Fibroblast growth factor receptor levels decrease during chick embryogenesis

    PubMed Central

    1990-01-01

    Two putative receptors for fibroblast growth factor (FGF) of approximately 150 and 200 kD were identified in membrane preparations from chick embryos. Specific binding (femtomoles/milligram) of 125I- aFGF to whole chick embryonic membranes was relatively constant from day 2 to 7, then decreased fivefold between days 7 and 13. Day-19 chick embryos retained 125I-aFGF binding at low levels to brain, eye, and liver tissues but not to skeletal muscle or cardiac tissues. The 200-kD FGF receptor began to decline between day 4.5 and 7 and was barely detectable by day 9, whereas the 150-kD FGF receptor began to decline by day 7 but was still detectable in day-9 embryonic membranes. It is not known whether the two FGF-binding proteins represent altered forms of one polypeptide, but it is clear that their levels undergo differential changes during development. Because endogenous chick FGF may remain bound to FGF receptor in membrane preparations, membranes were treated with acidic (pH 4.0) buffers to release bound FGF; such treatment did not affect 125I-aFGF binding and moderately increased the number of binding sites in day-7 and -19 embryos. Consequently, the observed loss of high affinity 125I-aFGF binding sites and FGF-binding polypeptides most likely represents a loss of FGF receptor protein. These experiments provide in vivo evidence to support the hypothesis that regulation of FGF receptor levels may function as a mechanism for controlling FGF-dependent processes during embryonic development. PMID:2153684

  19. A potent and selective NPY Y5 antagonist reduces food intake but not through blockade of the NPY Y5 receptor.

    PubMed

    Della-Zuana, O; Revereault, L; Beck-Sickinger, A; Monge, A; Caignard, D-H; Fauchère, J-L; Henlin, J-M; Audinot, V; Boutin, J A; Chamorro, S; Félétou, M; Levens, N

    2004-04-01

    These studies were performed to test the hypothesis that endogenous neuropeptide Y (NPY) acting on the NPY Y(5) receptor subtype contributes to the control of food intake. The hypothesis was tested using S 25585-a newly synthesized NPY Y(5) receptor antagonist. S 25585 was shown to be a high-affinity antagonist of the NPY Y(5) receptor subtype (IC(50) 5 nM) with no significant affinity toward other NPY receptor subtypes and over 40 other receptors, channels or uptake systems. S 25585 (7.5 mg/kg, i.p.) did not induce a conditioned taste aversion, significantly alter need-induced sodium appetite or induce pica, suggesting that at this dose the compound did not induce illness or malaise. In satiated rats, S 25585 (5.0 and 7.5 mg/kg, i.p.) significantly decreased the overfeeding induced by i.c.v. injection of NPY (1 microg) and the highly selective NPY Y(5) receptor agonist [hPP(1-17), Ala(31), Aib(32)]NPY (0.7 microg). In rats fasted for 4 h immediately before the dark phase, analysis of the microstructure of feeding behavior revealed that S 25585 significantly increased latency to eat and significantly decreased the duration and size of the meals without altering the meal number or eating rate. Analysis of the behavioral satiety sequence at this time revealed that the animals passed through the normal pattern of feeding, grooming and resting. Although S 25585 appeared to be influencing a physiological system controlling appetite, this does not involve the NPY Y(5) receptor since the antagonist also markedly reduced food intake in the NPY Y(5) knockout mouse. The results presented do not support a role for the NPY Y(5) receptor in the control of food intake. The results further illustrate that it is imperative that the activity of any new NPY Y(5) antagonist be assessed in the NPY Y(5) knockout mouse before assuming that its effect on food intake is due to blockade of this receptor.

  20. Nebivolol decreases endothelial cell stiffness via the estrogen receptor beta: a nano-imaging study.

    PubMed

    Hillebrand, Uta; Lang, Detlef; Telgmann, Ralph G; Hagedorn, Claudia; Reuter, Stefan; Kliche, Katrin; Stock, Christian M; Oberleithner, Hans; Pavenstädt, Hermann; Büssemaker, Eckhart; Hausberg, Martin

    2009-03-01

    Nebivolol (NEB) is a [beta]1-receptor blocker with nitric oxide-dependent vasodilating properties. NEB-induced nitric oxide release is mediated through the estrogen receptor. Here, we tested the hypothesis that NEB decreases endothelial cell stiffness and that these effects can be abolished by both endothelial nitric oxide synthase and estrogen receptor blockade. Human endothelial cells (EAHy-926) were incubated with vehicle, NEB 0.7 nmol/l, metoprolol 200 nmol/l, 17[beta]-estradiol (E2) 15 nmol/l, the estrogen receptor antagonists tamoxifen 100 nmol/l and ICI 182780 (ICI) 100 nmol/l, the nitric oxide synthase inhibitor N[omega]-nitro-L-arginine methyl ester 1 mmol/l and combinations of NEB and E2 with either tamoxifen, ICI or N[omega]-nitro-L-arginine methyl ester as well as metoprolol and ICI. Atomic force microscopy was performed to measure cellular stiffness, cell volume and apical surface. Presence of estrogen receptor protein in EAHy-926 was confirmed by western blot analysis; quantification of ER[alpha] and ER[beta] total RNA was performed by semiquantitative PCR. Both NEB as well as E2 decreased cellular stiffness to a similar extent (NEB: 0.83 +/- 0.03 pN/nm, E2: 0.87 +/- 0.03 pN/nm, vehicle: 2.19 +/- 0.07 pN/nm), whereas metoprolol had no effect on endothelial stiffness (2.07 +/- 0.04 pN/nm, all n = 60, P < 0.01). The decrease in stiffness occurred as soon as 5 min after starting NEB incubation. The effects are mediated through nongenomic ER[beta] pathways, as ER[alpha] is not translated into measurable protein levels in EAHy-926. Furthermore, NEB increased cell volume by 48 +/- 4% and apical surface by 34 +/- 3%. E2 had comparable effects. Tamoxifen, ICI and N[omega]-nitro-L-arginine methyl ester substantially diminished the effects of NEB and E2. NEB decreases cellular stiffness and causes endothelial cell growth. These effects are nitric oxide-dependent and mediated through nongenomic ER[beta] pathways. The morphological and functional alterations

  1. NMDA and AMPA/kainate glutamatergic receptors in the prelimbic medial prefrontal cortex modulate the elaborated defensive behavior and innate fear-induced antinociception elicited by GABAA receptor blockade in the medial hypothalamus.

    PubMed

    de Freitas, Renato Leonardo; Salgado-Rohner, Carlos José; Biagioni, Audrey Francisco; Medeiros, Priscila; Hallak, Jaime Eduardo Cecílio; Crippa, José Alexandre S; Coimbra, Norberto Cysne

    2014-06-01

    The aim of the present study was to investigate the involvement of N-methyl-d-aspartate (NMDA) and amino-3-hydroxy-5-methyl-isoxazole-4-proprionate (AMPA)/kainate receptors of the prelimbic (PL) division of the medial prefrontal cortex (MPFC) on the panic attack-like reactions evoked by γ-aminobutyric acid-A receptor blockade in the medial hypothalamus (MH). Rats were pretreated with NaCl 0.9%, LY235959 (NMDA receptor antagonist), and NBQX (AMPA/kainate receptor antagonist) in the PL at 3 different concentrations. Ten minutes later, the MH was treated with bicuculline, and the defensive responses were recorded for 10 min. The antagonism of NMDA receptors in the PL decreased the frequency and duration of all defensive behaviors evoked by the stimulation of the MH and reduced the innate fear-induced antinociception. However, the pretreatment of the PL cortex with NBQX was able to decrease only part of defensive responses and innate fear-induced antinociception. The present findings suggest that the NMDA-glutamatergic system of the PL is critically involved in panic-like responses and innate fear-induced antinociception and those AMPA/kainate receptors are also recruited during the elaboration of fear-induced antinociception and in panic attack-related response. The activation of the glutamatergic neurotransmission of PL division of the MPFC during the elaboration of oriented behavioral reactions elicited by the chemical stimulation of the MH recruits mainly NMDA receptors in comparison with AMPA/kainate receptors.

  2. Disruption of type 5 adenylyl cyclase prevents β-adrenergic receptor cardiomyopathy: a novel approach to β-adrenergic receptor blockade.

    PubMed

    Yan, Lin; Vatner, Stephen F; Vatner, Dorothy E

    2014-11-15

    β-Adrenergic receptor (β-AR) blockade is widely used to treat heart failure, since the adverse effects of chronic β-AR stimulation are central to the pathogenesis of this disease state. Transgenic (Tg) mice, where β-AR signaling is chronically enhanced by overexpression of cardiac β₂-ARs, is a surrogate for this mechanism, since these mice develop cardiomyopathy as reflected by reduced left ventricular (LV) function, increased fibrosis, apoptosis, and myocyte hypertrophy. We hypothesized that disruption of type 5 adenylyl cyclase (AC5), which is in the β-AR signaling pathway in the heart, but exerts only a minor β-AR blocking effect, could prevent the cardiomyopathy in β₂-AR Tg mice without the negative effects of full β-AR blockade. Accordingly, we mated β₂-AR Tg mice with AC5 knockout (KO) mice. The β₂-AR Tg × AC5 KO bigenic mice prevented the cardiomyopathy as reflected by improved LV ejection fraction, reduced apoptosis, fibrosis, and myocyte size and preserved exercise capacity. The rescue was not simply due to a β-blocking effect of AC5 KO, since neither baseline LV function nor the response to isoproterenol was diminished substantially compared with the negative inotropic effects of β-blockade. However, AC5 disruption in β₂-AR Tg activates the antioxidant, manganese superoxide dismutase, an important mechanism protecting the heart from cardiomyopathy. These results indicate that disruption of AC5 prevents the cardiomyopathy induced by chronically enhanced β-AR signaling in mice with overexpressed β₂-AR, potentially by enhancing resistance to oxidative stress and apoptosis, suggesting a novel, alternative approach to β-AR blockade. Copyright © 2014 the American Physiological Society.

  3. P2Y12 receptor blockade synergizes strongly with nitric oxide and prostacyclin to inhibit platelet activation

    PubMed Central

    Chan, Melissa V.; Knowles, Rebecca B. M.; Lundberg, Martina H.; Tucker, Arthur T.; Mohamed, Nura A.; Kirkby, Nicholas S.; Armstrong, Paul C. J.; Mitchell, Jane A.

    2016-01-01

    Aims In vivo platelet function is a product of intrinsic platelet reactivity, modifiable by dual antiplatelet therapy (DAPT), and the extrinsic inhibitory endothelial mediators, nitric oxide (NO) and prostacyclin (PGI2), that are powerfully potentiated by P2Y12 receptor blockade. This implies that for individual patients endothelial mediator production is an important determinant of DAPT effectiveness. Here, we have investigated this idea using platelets taken from healthy volunteers treated with anti‐platelet drugs. Methods Three groups of male volunteers (n = 8) received either prasugrel (10 mg), aspirin (75 mg) or DAPT (prasugrel + aspirin) once daily for 7 days. Platelet reactivity in the presence of diethylammonium (Z)‐1‐(N,N‐diethylamino)diazen‐1‐ium‐1,2‐diolate (DEA/NONOate) and PGI2 was studied before and following treatment. Results Ex vivo, PGI2 and/or DEA/NONOate had little inhibitory effect on TRAP‐6‐induced platelet reactivity in control conditions. However, in the presence of DAPT, combination of DEA/NONOate + PGI2 reduced platelet aggregation (74 ± 3% to 19 ± 6%, P < 0.05). In vitro studies showed even partial (25%) P2Y12 receptor blockade produced a significant (67 ± 2% to 39 ± 10%, P < 0.05) inhibition when DEA/NONOate + PGI2 was present. Conclusions We have demonstrated that PGI2 and NO synergize with P2Y12 receptor antagonists to produce powerful platelet inhibition. Furthermore, even with submaximal P2Y12 blockade the presence of PGI2 and NO greatly enhances platelet inhibition. Our findings highlight the importance of endothelial mediator in vivo modulation of P2Y12 inhibition and introduces the concept of refining ex vivo platelet function testing by incorporating an assessment of endothelial function to predict thrombotic outcomes better and adjust therapy to prevent adverse outcomes in individual patients. PMID:26561399

  4. Activation but not blockade of GABAB receptors during early-life alters anxiety in adulthood in BALB/c mice.

    PubMed

    Sweeney, Fabian F; O'Leary, Olivia F; Cryan, John F

    2014-06-01

    Although the underlying pathophysiology of anxiety disorders is unknown it is clear that a combination of genetic and environmental factors in early life predispose to disease risk. Preclinical research increasingly suggests an important role for the GABAB receptor in modulating anxiety behaviour, with GABAB receptor deficient mice having increased anxiety behaviour. Previous studies have highlighted critical windows during development where adult anxiety behaviour is primed. However, little is known regarding the role played by the GABAB receptors in the developmental processes that underlie adult anxiety behaviour. To this end, we treated male BALB/c mouse pups with the either the selective GABAB receptor agonist, R-baclofen (2 mg/kg, s.c), the GABAB receptor antagonist CGP 52432 (10 mg/kg and 30 mg/kg) or vehicle from postnatal days (P) 14-28. The anxiety behaviour of these mice was then assessed in adulthood (P62 onwards) in a battery of behavioural tests comprising; the stress induced hyperthermia (SIH) test, defensive marble burying (DMB), elevated-plus maze (EPM) and the forced swim test (FST). Postnatal R-baclofen treatment resulted in increased anxiety-like behaviour in the EPM as shown by approach-avoidance and ethological measures. Other behavioural measures were not significantly altered. Interestingly, blockade of GABAB receptors with CGP52432 in early life caused no alterations in emotional behaviour. These data suggest that during early life GABAB receptor signalling can play a functional role in programing anxiety behaviour in adulthood. The underlying neurodevelopmental processes underlying these effects remain to be discovered.

  5. Doxepin and diphenhydramine increased non-rapid eye movement sleep through blockade of histamine H1 receptors.

    PubMed

    Wang, Yi-Qun; Takata, Yohko; Li, Rui; Zhang, Ze; Zhang, Meng-Qi; Urade, Yoshihiro; Qu, Wei-Min; Huang, Zhi-Li

    2015-02-01

    Histaminergic neurons have been reported to play an important role in the regulation of sleep-wake behavior through the histamine H1 receptor (R, H1R). First generation H1R antagonists, such as doxepin and diphenhydramine, produce drowsiness in humans, and are occasionally used to treat insomnia. However, if H1R antagonists function via physically blocking the H1R remains unclear. In the current study, we used H1R knockout (KO) mice to investigate if the sleep-promoting effects of doxepin and diphenhydramine are dependent on blockade of the H1R. When doxepin was administered, non-rapid eye movement (NREM) sleep in wild type (WT) mice increased for 4h, with an increase in the numbers of NREM sleep bouts of 256-512 s and 512-1024 s. These effects were not observed in the H1R KO mice. Furthermore, diphenhydramine increased NREM sleep for 6h in WT, and not in the H1R KO mice after the injection. These results indicate that both doxepin at 15 mg/kg and diphenhydramine at 10 mg/kg induce NREM sleep through blockade of H1R.

  6. Angiotensin type I receptor blockade in conjunction with enhanced Akt activation restores coronary collateral growth in the metabolic syndrome

    PubMed Central

    Jadhav, Rashmi; Dodd, Tracy; Smith, Erika; Bailey, Erin; DeLucia, Angelo L.; Russell, James C.; Madison, Rowan; Potter, Barry; Walsh, Kenneth; Jo, Hanjoong

    2011-01-01

    We have previously demonstrated that Akt was required for repetitive ischemia (RI)-induced coronary collateral growth (CCG) in healthy rats but was not activated by RI in the metabolic syndrome (JCR:LA-cp rats) where CCG was impaired. Here we hypothesized that failure of angiotensin type I receptor (AT1R) blockers to restore Akt activation is a key determinant of their inability to completely restore CCG in the metabolic syndrome. Therefore, we investigated whether adenovirus-mediated delivery of constitutively active Akt (MyrAkt-Adv) in conjunction with AT1R blockade (candesartan) was able to restore RI-induced CCG in JCR:LA-cp rats. Successful myocardial MyrAkt-Adv delivery was confirmed by a >80% transduction efficiency and an approximately fourfold increase in Akt expression and activation. CCG was assessed by myocardial blood flow measurements in the normal and collateral-dependent zones. MyrAkt-Adv alone significantly increased RI-induced CCG in JCR:LA-cp rats (∼30%), but it completely restored CCG in conjunction with administration of candesartan. In contrast, dominant negative Akt (DN-Akt-Adv) reversed the beneficial effect of candesartan on CCG in JCR:LA-cp rats. We conclude that optimal restoration of coronary collateral growth in JCR:LA-cp rats requires a combination of AT1R blockade with constitutive Akt activation. These findings may carry implications for metabolic syndrome patients in need of coronary revascularization. PMID:21335466

  7. Prorenin/Renin Receptor Blockade Promotes a Healthy Fat Distribution in Obese Mice

    PubMed Central

    Tan, Paul; Blais, Carolane; Nguyen, Thi M.-D.; Schiller, Peter W.; Gutkowska, Jolanta; Lavoie, Julie L.

    2016-01-01

    Objective Administration of the handle region peptide (HRP), a (pro)renin receptor blocker, decreases body weight gain and visceral adipose tissue (VAT) in high-fat/high-carbohydrate (HF/HC) diet-fed mice. The objective of this study was to elucidate potential mechanisms implicated in these observations. Methods Mice were given a normal or a HF/HC diet along with saline or HRP for 10 weeks. Results In HF/HC-fed mice, HRP increased the expression of several enzymes implicated in lipogenesis and lipolysis in subcutaneous fat (SCF) while the expression of the enzyme implicated in the last step of lipogenesis decreased in VAT. A reduction was also observed in circulating free fatty acids in these animals which was accompanied by normalized adipocyte size in VAT and increased adipocyte size in SCF. “Beiging“ is the evolution of a white adipose tissue toward a brown-like phenotype characterized by an increased mitochondrial density and small lipid droplets. HRP increased the expression of’ “beiging” markers in SCF of HF/HC diet-fed mice. Conclusions HRP treatment may favor healthy fat storage in SCF by activating a triglyceride/free fatty acid cycling and “beiging,” which could explain the body weight and fat mass reduction. PMID:27458124

  8. Blockade of Tim-1 and Tim-4 Enhances Atherosclerosis in LDL Receptor-Deficient Mice

    PubMed Central

    Foks, Amanda C.; Engelbertsen, Daniel; Kuperwaser, Felicia; Alberts-Grill, Noah; Gonen, Ayelet; Witztum, Joseph L.; Lederer, James; Jarolim, Petr; DeKruyff, Rosemarie H.; Freeman, Gordon J.; Lichtman, Andrew H.

    2016-01-01

    Objective T cell immunoglobulin and mucin domain (Tim) proteins are expressed by numerous immune cells, recognize phosphatidylserine (PS) on apoptotic cells and function as costimulators or coinhibitors. Tim-1 is expressed by activated T cells but is also found on dendritic cells and B cells. Tim-4, present on macrophages and dendritic cells, plays a critical role in apoptotic cell clearance, regulates the number of PS-expressing activated T cells and is genetically associated with low LDL and triglyceride levels. Since these functions of Tim-1 and Tim-4 could affect atherosclerosis, their modulation has potential therapeutic value in cardiovascular disease. Approach and Results ldlr−/− mice were fed a high-fat diet for 4 weeks while being treated with control (rat IgG1) or anti-Tim-1 (3D10) or -Tim-4 (21H12) mAbs that block PS recognition and phagocytosis. Both anti-Tim-1 and anti-Tim-4 treatments enhance atherosclerosis by 45% compared with controls by impairment of efferocytosis and increasing aortic CD4+T cells. Consistently, anti-Tim-4-treated mice show increased percentages of activated T cells and 'late' apoptotic cells in the circulation. Moreover, in vitro blockade of Tim-4 inhibited efferocytosis of oxLDL-induced apoptotic macrophages. Whereas anti-Tim-4 treatment increased Th1 and Th2 responses, anti-Tim-1 induced Th2 responses but dramatically reduced the percentage of Tregs. Finally, combined blockade of Tim-1 and Tim-4 increased atherosclerotic lesion size by 59%. Conclusion Blockade of Tim-4 aggravates atherosclerosis likely by prevention of phagocytosis of PS-expressing apoptotic cells and activated T cells by Tim-4-expressing cells, whereas Tim-1-associated effects on atherosclerosis are related to changes in Th1/Th2 balance and reduced circulating Tregs. PMID:26821944

  9. The simultaneous blockade of chemokine receptors CCR2, CCR5 and CXCR3 by a non-peptide chemokine receptor antagonist protects mice from dextran sodium sulfate-mediated colitis.

    PubMed

    Tokuyama, Hirotake; Ueha, Satoshi; Kurachi, Makoto; Matsushima, Kouji; Moriyasu, Fuminori; Blumberg, Richard S; Kakimi, Kazuhiro

    2005-08-01

    Chemokine receptors CCR2, CCR5 and CXCR3 are involved in the regulation of macrophage- and T cell-mediated immune responses and in the migration and activation of these cells. In order to determine whether blockade of these chemokine receptors modulates intestinal inflammation, we investigated here the effect of a non-peptide chemokine receptor antagonist, TAK-779 (N,N-dimethyl-N-[4-[[[2-(4-methylphenyl)-6,7-dihydro-5H-benzocyclohepten-8-yl]carbonyl]amino]benzyl]-tetrahydro-2H-pyran-4-aminium chloride), in mice with dextran sodium sulfate (DSS)-induced experimental colitis. C57BL/6 mice were fed 5% DSS in their drinking water for up to 7 days with or without the administration of TAK-779. The severity of inflammation in the colon was assessed by clinical signs and histological examination. Infiltration of inflammatory cells into the mucosa was analyzed by immunohistochemistry, and the expression of cytokine and chemokine mRNAs in tissues was quantitated by reverse transcription-PCR. During DSS-induced colitis, the recruitment of monocytes/macrophages into the colonic mucosa and the induction of proinflammatory cytokines correlated with the severity of intestinal inflammation. The onset of clinical signs and histopathologic features were delayed in animals treated with TAK-779. The expression of CCR2, CCR5 and CXCR3 mRNAs was inhibited in the TAK-779-treated mice. Consistent with these results, infiltration of monocytes/macrophages into the lamina propria was almost completely inhibited and the expression of colonic IL-1beta and IL-6 was significantly decreased in the TAK-779-treated mice. The blockade of CCR2, CCR5 and CXCR3 prevents murine experimental colitis by inhibiting the recruitment of inflammatory cells into the mucosa. Therefore, chemokines and their receptors may be therapeutic targets for the treatment of inflammatory bowel disease.

  10. Selective blockade of 5-HT2A receptors attenuates the increased temperature response in brown adipose tissue to restraint stress in rats.

    PubMed

    Ootsuka, Youichirou; Blessing, William W; Nalivaiko, Eugene

    2008-03-01

    Previous studies have demonstrated that 5-HT2A receptors may be involved in the central control of thermoregulation and of the cardiovascular system. Our aim was to test whether these receptors mediate thermogenic and tachycardiac responses induced by acute psychological stress. Three groups of adult male Hooded Wistar rats were instrumented with: (i) a thermistor in the interscapular area (for recording brown adipose tissue temperature) and an ultrasound Doppler probe (to record tail blood flow); (ii) temperature dataloggers to record core body temperature; (iii) ECG electrodes. On the day of the experiment, rats were subjected to a 30-min restraint stress preceded by s.c. injection of either vehicle or SR-46349B (a serotonin 2A receptor antagonist) at doses of 0.01, 0.1 and 1.0 mg/kg. The restraint stress caused a rise in brown adipose tissue temperature (from, mean +/- s.e.m., 36.6 +/- 0.2 to 38.0 +/- 0.2 degrees C), transient cutaneous vasoconstriction (tail blood flow decreased from 12 +/- 2 to 5 +/- 1 cm/s), increase in heart rate (from 303 +/- 15 to 453 +/- 15 bpm at the peak, then reduced to 393 +/- 12 bpm at the steady state), and defaecation (6 +/- 1 pellets per restraint session). The core body temperature was not affected by the restraint. Blockade of 5-HT2A receptors attenuated the increase in brown adipose tissue temperature and transient cutaneous vasoconstriction, but not tachycardia and defaecation elicited by restraint stress. These results indicate that psychological stress causes activation of 5-HT2A receptors in neural pathways that control thermogenesis in the brown adipose tissue and facilitate cutaneous vasoconstriction.

  11. Cortisol receptor blockade and seawater adaptation in the euryhaline teleost Fundulus heteroclitus

    USGS Publications Warehouse

    Marshall, W.S.; Cozzi, R.R.F.; Pelis, R.M.; McCormick, S.D.

    2005-01-01

    To examine the role of cortisol in seawater osmoregulation in a euryhaline teleost, adult killifish were acclimated to brackish water (10???) and RU486 or vehicle was administered orally in peanut oil daily for five days at low (40 mg.kg-1) or high dose (200 mg.kg-1). Fish were transferred to 1.5 x seawater (45???) or to brackish water (control) and sampled at 24 h and 48 h after transfer, when Cl- secretion is upregulated. At 24 h, opercular membrane Cl- secretion rate, as Isc, was increased only in the high dose RU486 group. Stimulation of membranes by 3-isobutyl-1-methylxanthine and cAMP increased Isc in vehicle treated controls but those from RU486-treated animals were unchanged and membranes from brackish water animals showed a decrease in Isc. At 48 h, Isc increased and transepithelial resistance decreased in vehicle and RU486 groups, compared to brackish water controls. Plasma cortisol increased in all groups transferred to high salinity, compared to brackish water controls. RU486 treated animals had higher cortisol levels compared to vehicle controls. Vehicle treated controls had lower cortisol levels than untreated or RU486 treated animals, higher stimulation of Isc, and lower hematocrit at 24 h, beneficial effects attributed to increased caloric intake from the peanut oil vehicle. Chloride cell density was significantly increased in the high dose RU486 group at 48 hours, yet Isc was unchanged, suggesting a decrease in Cl- secretion per cell. Thus cortisol enhances NaCl secretion capacity in chloride cells, likely via glucocorticoid type receptors. ?? 2005 Wiley-Liss, Inc.

  12. D1, but not D2, receptor blockade within the infralimbic and medial orbitofrontal cortex impairs cocaine seeking in a region-specific manner.

    PubMed

    Cosme, Caitlin V; Gutman, Andrea L; Worth, Wensday R; LaLumiere, Ryan T

    2016-08-31

    Evidence suggests that the infralimbic cortex (IL), a subregion of the ventromedial prefrontal cortex (vmPFC), suppresses cocaine-seeking behavior in a self-administration paradigm, whereas the more anterior vmPFC subregion, the medial orbitofrontal cortex (mOFC), has received very little attention in this regard. Despite the established dopaminergic innervation of the vmPFC, whether dopamine receptor blockade in each subregion alters the reinstatement of cocaine seeking is unclear. To address this issue, male Sprague-Dawley rats underwent 2 weeks of cocaine self-administration, followed by extinction training and reinstatement testing. Immediately prior to each reinstatement test, rats received microinjections of the D1 receptor antagonist SCH 23390, the D2 receptor antagonist sulpiride or their respective vehicles. D1 receptor blockade in the IL reduced cued reinstatement but had no effect on cocaine prime and cue + cocaine-prime reinstatement, whereas D2 receptor blockade in the IL had no effect on reinstatement. For the mOFC, however, D1 receptor blockade reduced cocaine seeking in all reinstatement types, whereas blocking D2 receptors in the mOFC had no effect on any form of cocaine seeking. These findings suggest different roles for D1 receptors in the IL versus the mOFC in regulating cocaine-seeking behavior. Moreover, even as previous work indicates that IL inactivation does not affect reinstatement but, rather, induces cocaine seeking during extinction, the present findings suggest that dopamine receptor activation in the IL is necessary for cocaine seeking under some circumstances.

  13. Pharmacological blockade of either cannabinoid CB1 or CB2 receptors prevents both cocaine-induced conditioned locomotion and cocaine-induced reduction of cell proliferation in the hippocampus of adult male rat.

    PubMed

    Blanco-Calvo, Eduardo; Rivera, Patricia; Arrabal, Sergio; Vargas, Antonio; Pavón, Francisco Javier; Serrano, Antonia; Castilla-Ortega, Estela; Galeano, Pablo; Rubio, Leticia; Suárez, Juan; Rodriguez de Fonseca, Fernando

    2014-01-01

    Addiction to major drugs of abuse, such as cocaine, has recently been linked to alterations in adult neurogenesis in the hippocampus. The endogenous cannabinoid system modulates this proliferative response as demonstrated by the finding that pharmacological activation/blockade of cannabinoid CB1 and CB2 receptors not only modulates neurogenesis but also modulates cell death in the brain. In the present study, we evaluated whether the endogenous cannabinoid system affects cocaine-induced alterations in cell proliferation. To this end, we examined whether pharmacological blockade of either CB1 (Rimonabant, 3 mg/kg) or CB2 receptors (AM630, 3 mg/kg) would affect cell proliferation [the cells were labeled with 5-bromo-2'-deoxyuridine (BrdU)] in the subventricular zone (SVZ) of the lateral ventricle and the dentate subgranular zone (SGZ). Additionally, we measured cell apoptosis (as monitored by the expression of cleaved caspase-3) and glial activation [by analyzing the expression of glial fibrillary acidic protein (GFAP) and Iba-1] in the striatum and hippocampus during acute and repeated (4 days) cocaine administration (20 mg/kg). The results showed that acute cocaine exposure decreased the number of BrdU-immunoreactive (ir) cells in the SVZ and SGZ. In contrast, repeated cocaine exposure reduced the number of BrdU-ir cells only in the SVZ. Both acute and repeated cocaine exposure increased the number of cleaved caspase-3-, GFAP- and Iba1-ir cells in the hippocampus, and this effect was counteracted by AM630 or Rimonabant, which increased the number of BrdU-, GFAP-, and Iba1-ir cells in the hippocampus. These results indicate that the changes in neurogenic, apoptotic and gliotic processes that were produced by repeated cocaine administration were normalized by pharmacological blockade of CB1 and CB2. The restorative effects of cannabinoid receptor blockade on hippocampal cell proliferation were associated with the prevention of the induction of conditioned locomotion

  14. Blockade of dorsal hippocampal orexin-1 receptors impaired morphine-induced state-dependent learning.

    PubMed

    Farahmandfar, Maryam; Kadivar, Mehdi; Rastipisheh, Sareh

    2016-12-01

    Behavioral abnormalities associated with opiate addiction include memory and learning deficits, which are the result of some alterations in the neuromodulatory systems. Recently, orexin has shown to influence drug addiction neural circuitry, specifically in mediating reward-related perception and memory. To explore the possible interaction of orexinergic and opioidergic system on modulation of learning and memory, we have investigated the effects of intra-dorsal hippocampal (intra-CA1) administration of orexin-1 receptor agonist and the competitive orexin-1 antagonist, SB-334867, on morphine-induced memory impairment by using step-down passive avoidance task in mice. Pre-training injection of morphine (5mg/kg, i.p.) impaired memory, which was restored when 24h later the same dose of the drug was administered. Pre-test administration of orexin-1 (0.5, 5 and 50pmol, intra-CA1) had not a significant effect on the retention latency compared to the saline-treated animals, but it restored the memory impairment induced by pre-training morphine (5mg/kg, i.p.). Pre-test administration of SB-334867 (10, 20 and 40nmol, intra-CA1) by itself decreased the retention latencies of passive avoidance task. Co-administration of orexin-1 (0.5, 5 and 50pmol, intra-CA1) and morphine (1mg/kg, i.p.) on the test day induced morphine state-dependent memory. Conversely, pre-test injection of SB-334867 (10, 20 and 40nmol, intra-CA1) inhibited the orexin-1-induced potentiation of morphine state-dependent learning on the test day. It is concluded that dorsal hippocampal orexin-1 receptors may be involved, at least in part, in morphine state-dependent learning in mice. Copyright © 2016 Elsevier Ltd. All rights reserved.

  15. Adenosine A2A receptor blockade differentially influences excitotoxic mechanisms at pre- and postsynaptic sites in the rat striatum.

    PubMed

    Tebano, Maria Teresa; Pintor, Annita; Frank, Claudio; Domenici, Maria Rosaria; Martire, Alberto; Pepponi, Rita; Potenza, Rosa Luisa; Grieco, Rosa; Popoli, Patrizia

    2004-07-01

    Adenosine A(2A) receptor antagonists are being regarded as potential neuroprotective drugs, although the mechanisms underlying their effects need to be better studied. The aim of this work was to investigate further the mechanism of the neuroprotective action of A(2A) receptor antagonists in models of pre- and postsynaptic excitotoxicity. In microdialysis studies, the intrastriatal perfusion of the A(2A) receptor antagonist ZM 241385 (5 and 50 nM) significantly reduced, in an inversely dose-dependent way, the raise in glutamate outflow induced by 5 mM quinolinic acid (QA). In rat corticostriatal slices, ZM 241385 (30-100 nM) significantly reduced 4-aminopyridine (4-AP)-induced paired-pulse inhibition (PPI; an index of neurotransmitter release), whereas it worsened the depression of field potential amplitude elicited by N-methyl-D-aspartate (NMDA; 12.5 and 50 microM). The A(2A) antagonist SCH 58261 (30 nM) mimicked the effects of ZM 241385, whereas the A(2A) agonist CGS 21680 (100 nM) showed a protective influence toward 50 microM NMDA. In rat striatal neurons, 50 nM ZM 241385 did not affect the increase in [Ca(2+)](i) or the release of lactate dehydrogenase (LDH) induced by 100 and 300 microM NMDA, respectively. The ability of ZM 241385 to prevent QA-induced glutamate outflow and 4-AP-induced effects confirms that A(2A) receptor antagonists have inhibitory effects on neurotransmitter release, whereas the results obtained toward NMDA-induced effects suggest that A(2A) receptor blockade does not reduce, or even amplifies, excitotoxic mechanisms due to direct NMDA receptor stimulation. This indicates that the neuroprotective potential of A(2A) antagonists may be evident mainly in models of neurodegeneration in which presynaptic mechanisms play a major role.

  16. Selective blockade of 5-hydroxytryptamine (5-HT)7 receptors enhances 5-HT transmission, antidepressant-like behavior, and rapid eye movement sleep suppression induced by citalopram in rodents.

    PubMed

    Bonaventure, Pascal; Kelly, Lisa; Aluisio, Leah; Shelton, Jonathan; Lord, Brian; Galici, Ruggero; Miller, Kirsten; Atack, John; Lovenberg, Timothy W; Dugovic, Christine

    2007-05-01

    Evidence has accumulated supporting a role for 5-hydroxytryptamine (5-HT)7 receptors in circadian rhythms, sleep, and mood disorders, presumably as a consequence of the modulation of 5-HT-mediated neuronal activity. We hypothesized that a selective 5-HT7 receptor antagonist, (2R)-1-[(3-hydroxyphenyl)sulfonyl]-2-[2-(4-methyl-1-piperidinyl)ethyl]-pyrrolidine (SB-269970), should increase activity of 5-HT neurons and potentiate the effect of selective serotonin reuptake inhibitors (citalopram). In rats, administration of 3 mg/kg s.c. citalopram alone increased the extracellular concentration of 5-HT. This effect of citalopram on extracellular 5-HT concentration was significantly enhanced by an ineffective dose of SB-269970. Combining this dose of SB-269970 with a low dose of citalopram also resulted in a significant increase in extracellular concentration of 5-HT, suggesting a potentiation of neurochemical effects. In mice, citalopram and SB-269970 dose-dependently decreased immobility time in the tail suspension test. The dose-effect curve of citalopram was shifted leftward by coadministration of an effective dose of SB-269970. Furthermore, combining ineffective doses of citalopram and SB-269970 also resulted in a significant decrease of immobility time in the tail suspension test, suggesting potentiation of antidepressant-like effects. In rats, SB-269970 potentiated the increase of rapid eye movement (REM) latency and the REM sleep decrease induced by citalopram. SB-269970 also reversed the increase in sleep fragmentation induced by citalopram. Rat plasma and brain concentrations of citalopram were not affected by coadministration of SB-269970, arguing for a pharmacodynamic rather than a pharmacokinetic mechanism. Overall, these results indicate that selective blockade of 5-HT7 receptors may enhance the antidepressant efficacy of citalopram and may provide a novel therapy to alleviate sleep disturbances associated with depression.

  17. Long-term effects of amygdala GABA receptor blockade on specific subpopulations of hippocampal interneurons.

    PubMed

    Berretta, Sabina; Lange, Nicholas; Bhattacharyya, Sujoy; Sebro, Ronnie; Garces, Jessica; Benes, Francine M

    2004-01-01

    Growing evidence indicates that the amygdala modulates hippocampal functions. To test the hypothesis that this modulation may involve long-lasting effects on interneuronal networks in the hippocampus, changes in the expression of neurochemical markers specific for different interneuronal subpopulations were assessed in adult rats 96 h following acute infusion of low doses of the GABAA receptor antagonist picrotoxin into the amygdala. The numerical density (Nd) of somata showing immunoreactivity (IR) for parvalbumin (PVB) was decreased in dentate gyrus (DG) and the CA4-2 region, while that of calretinin (CR)-IR was decreased in DG and CA2. The Nd of calbindin D28k (CB)-IR somata was decreased in CA3-2. The densities of axon terminals arising from PVB-IR and cholecystokinin (CCK)-IR basket neurons were also altered, with those of CCK-IR terminals increased across all sectors, while PVB-IR terminals were decreased only in the CA region. Increases in CCK-IR terminals were paralleled by increases of terminals with IR for the 65-kD isoform of glutamate decarboxylase (GAD65). Mixed-effects statistical models, adapted specifically for these analyses, indicated that perturbations of amygdalar inputs to the hippocampus significantly alter the drive that hippocampal PVB-, CR-, and CB-IR neurons within the dentate gyrus/CA4 region exercise on CCK-IR terminals within the same region as well as in CA3-1. These results suggest that amygdalar modulation of specific neuronal subpopulations may induce lasting and far-reaching changes in the hippocampus during normal functioning, as well as in diseases involving a disruption of amygdalar activity. In particular, changes in specific interneuronal markers within selective hippocampal sectors detected in the present results are strikingly similar to those reported in this region in schizophrenia. These similarities suggest that, in this disease, a disruption of GABAergic transmission within the amygdala may play a significant role in

  18. Peripheral benzodiazepine receptors are decreased during cocaine withdrawal in humans.

    PubMed

    Javaid, J I; Notorangelo, M P; Pandey, S C; Reddy, P L; Pandey, G N; Davis, J M

    1994-07-01

    In the present study, homovanillic acid in plasma (pHVA) and benzodiazepine receptors (3H-PK11195 binding) in neutrophil membranes were determined in blood obtained from cocaine-dependent (DSM-III-R) adult male inpatients at baseline-(within 72 hr of last cocaine use) and after 3 weeks of cocaine abstinence, and normal controls. The mean (+/- SEM) pHVA at baseline (10.3 ng/ml +/- 1.1) was similar to normals and did not change after 3 weeks of cocaine abstinence. Similarly, the binding indices of benzodiazepine receptors in cocaine-dependent subjects as a group were not significantly different than in normal controls. In 10 cocaine-dependent subjects, however, where both blood samples were available, the number of 3H-PK11195 binding sites was significantly (p < 0.05) decreased after 3 weeks of cocaine abstinence (mean +/- sem: Bmax = 6371 +/- 657 fmol/mg protein) compared with baseline (Bmax = 7553 +/- 925 fmol/mg protein), although there were no differences in the binding affinity (mean +/- sem: KD = 8.6 +/- 1.2 nmol/L after 3 weeks of abstinence compared with 8.1 +/- 1.0 nmol/L at baseline). These preliminary results suggest that peripheral benzodiazepine receptors may play an important role in the pathophysiology of cocaine withdrawal in cocaine-dependent human subjects.

  19. Mineralocorticoid receptor blockade prevents Western diet-induced diastolic dysfunction in female mice.

    PubMed

    Bostick, Brian; Habibi, Javad; DeMarco, Vincent G; Jia, Guanghong; Domeier, Timothy L; Lambert, Michelle D; Aroor, Annayya R; Nistala, Ravi; Bender, Shawn B; Garro, Mona; Hayden, Melvin R; Ma, Lixin; Manrique, Camila; Sowers, James R

    2015-05-01

    Overnutrition/obesity predisposes individuals, particularly women, to diastolic dysfunction (DD), an independent predictor of future cardiovascular disease. We examined whether low-dose spironolactone (Sp) prevents DD associated with consumption of a Western Diet (WD) high in fat, fructose, and sucrose. Female C57BL6J mice were fed a WD with or without Sp (1 mg·kg(-1)·day(-1)). After 4 mo on the WD, mice exhibited increased body weight and visceral fat, but similar blood pressures, compared with control diet-fed mice. Sp prevented the development of WD-induced DD, as indicated by decreased isovolumic relaxation time and an improvement in myocardial performance (decreased diastolic relaxation time/increased diastolic initial filling rate, as assessed by MRI. The relationship between passive sarcomere length of cardiac myocytes and ventricular pressure was monitored using di-8-ANEPPS staining of the t-tubule network in hearts ex vivo. Sp administration led to longer sarcomere lengths at each pressure indicative of improved ventricular compliance in WD-fed mice. Sp also prevented left ventricular hypertrophy, interstitial fibrosis, and oxidative stress. Sp prevented the WD-induced increased expression of myocardial proinflammatory M1 macrophage markers monocyte chemoattractant protein-1 and CD11c and increased the expression of the anti-inflammatory M2 macrophage marker CD206. These findings demonstrate that WD-induced DD is associated with increased oxidant stress, fibrosis, and immune dysregulation. Mineralocorticoid receptor antagonism enhanced M2 macrophage polarization and ameliorated oxidant stress and fibrosis. This work supports a novel blood pressure-independent effect of MR antagonism as a strategy to prevent diet-induced DD in women. Mineralocorticoid antagonism; low-dose spironolactone; aldosterone;high-fat diet; high-fructose diet; oxidative stress

  20. Lithium attenuated the behavioral despair induced by acute neurogenic stress through blockade of opioid receptors in mice.

    PubMed

    Khaloo, Pegah; Sadeghi, Banafshe; Ostadhadi, Sattar; Norouzi-Javidan, Abbas; Haj-Mirzaian, Arya; Zolfagharie, Samira; Dehpour, Ahmad-Reza

    2016-10-01

    Major depressive disorder is disease with high rate of morbidity and mortality. Stressful events lead to depression and they can be used as a model of depression in rodents. In this study we aimed to investigate whether lithium modifies the stressed-induced depression through blockade of opioid receptors in mice. We used foot shock stress as stressor and forced swimming test (FST), tail suspension test (TST) and open field test (OFT) to evaluation the behavioral responses in mice. We also used naltrexone hydrochloride (as opioid receptor antagonist), and morphine (as opioid receptor agonist). Our results displayed that foot-shock stress significantly increased the immobility time in TST and FST but it could not change the locomotor behavior in OFT. When we combined the low concentrations of lithium and naltrexone a significant reduction in immobility time was seen in the FST and TST in comparison with control foot-shock stressed group administered saline only. Despite the fact that our data showed low concentrations of lithium, when administered independently did not significantly affect the immobility time. Also our data indicated that concurrent administration of lithium and naltrexone had no effect on open field test. Further we demonstrated that simultaneous administration of morphine and lithium reverses the antidepressant like effect of active doses of lithium. Our data acclaimed that we lithium can augment stressed-induced depression and opioid pathways are involved in this action. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  1. EFFECT OF AT1 RECEPTOR BLOCKADE ON INTERMITTENT HYPOXIA-INDUCED ENDOTHELIAL DYSFUNCTION

    PubMed Central

    Marcus, Noah J.; Philippi, Nathan R.; Bird, Cynthia E.; Li, Yu-Long; Schultz, Harold D.; Morgan, Barbara J.

    2012-01-01

    Chronic intermittent hypoxia (CIH) raises arterial pressure, impairs vasodilator responsiveness, and increases circulating angiotensin II (Ang II); however, the role of Ang II in CIH-induced vascular dysfunction is unknown. Rats were exposed to CIH or room air (NORM), and a subset of these animals was treated with losartan (Los) during the exposure period. After 28 days, vasodilatory responses to acetylcholine or nitroprusside were measured in isolated gracilis arteries. Superoxide levels and Ang II receptor protein expression were measured in saphenous arteries. After 28 days, arterial pressure was increased and acetylcholine-induced vasodilation was blunted in CIH vs. NORM, and this was prevented by Los. Responses to nitroprusside and superoxide levels did not differ between CIH and NORM. Expression of AT2R was decreased and the AT1R:AT2R ratio was increased in CIH vs. NORM, but this was unaffected by Los. These results indicate that the blood pressure elevation and endothelial dysfunction associated with CIH is dependent, at least in part, on RAS signaling. PMID:22728949

  2. SB-334867, an orexin receptor 1 antagonist, decreased seizure and anxiety in pentylenetetrazol-kindled rats.

    PubMed

    Kordi Jaz, Elham; Moghimi, Ali; Fereidoni, Masoud; Asadi, Saeedeh; Shamsizadeh, Ali; Roohbakhsh, Ali

    2017-04-01

    Convulsive seizures are due to abnormal synchronous and repetitive neuronal discharges in the central nervous system (CNS). Finding new therapeutics to overcome the side effects of the current drug therapies and to increase their effectiveness is ongoing. Orexin-A and orexin-B are brain neuropeptides originating from postero-lateral hypothalamic neurons. Studies show that orexins, through activation of OX1 and OX2 receptors, have excitatory effects in the CNS. Accordingly, this study was designed to evaluate the effect of OX1 receptor antagonist (SB-334867) on seizure- and anxiety-related behaviors of pentylenetetrazol (PTZ)-kindled rats. Kindling was induced by repeated intraperitoneal (IP) injections of PTZ (32 mg/kg) with two-day intervals for 24 days in male Wistar rats. Three groups received intracerebroventricular (ICV) injections of SB-334867 (2.5, 5, and 10 μg/rat) before PTZ injections. Two control groups received vehicle (2 μL/rat, ICV) and valproate (26 μg/rat, ICV) before PTZ injections. An extra group of control animals received saline both ICV and IP. Seizure-related behaviors were monitored for 30 min following PTZ administration. The anxiety-like behaviors were also assessed using elevated plus-maze in the first and last days of the study. The results revealed that ICV injection of SB-334867, mainly at the dose of 10 μg/rat, decreased the median of seizure stages, prolonged the latency and reduced the duration of different seizure stages, and reversed the PTZ-induced anxiety-like behaviors. Based on the presented results, it is suggested that pharmacological blockade of the OX1 receptor is a potential target in the treatment of seizure and concomitant anxiety disorders. © 2016 Société Française de Pharmacologie et de Thérapeutique.

  3. Blockade of the tumor necrosis factor-related apoptosis inducing ligand death receptor DR5 prevents beta-amyloid neurotoxicity.

    PubMed

    Uberti, Daniela; Ferrari-Toninelli, Giulia; Bonini, Sara Anna; Sarnico, Ilenia; Benarese, Marina; Pizzi, Marina; Benussi, Luisa; Ghidoni, Roberta; Binetti, Giuliano; Spano, PierFranco; Facchetti, Fabio; Memo, Maurizio

    2007-04-01

    We originally suggested that inhibition of tumor necrosis factor-related apoptosis inducing ligand (TRAIL) death pathway could be taken into consideration as a potential therapeutic strategy for Alzheimer's disease (AD). However, because the critical role of TRAIL in immune surveillance, the neutralization of TRAIL protein by an antibody to prevent its binding to death receptors is definitely a risky approach. Here, we demonstrated that the blockade of the TRAIL death receptor DR5 with a specific antibody completely prevented amyloid beta peptide (A beta) neurotoxicity in both neuronal cell line and primary cortical neurons. DR5 was demonstrated to be a key factor in TRAIL death pathway. In fact, whereas TRAIL expression was enhanced dose-dependently by concentrations of beta amyloid ranging from 10 nM to 1 microM, only the highest toxic dose of A beta (25 microM) induced the increased expression of DR5 and neuronal cell death. In addition, the increased expression of DR5 receptor after beta amyloid treatment was sustained by p53 transcriptional activity, as demonstrated by the data showing that the p53 inhibitor Pifithrin alpha prevented both beta amyloid-induced DR5 induction and cell death. These data suggest a sequential activation of p53 and DR5 upon beta amyloid exposure. Further insight into the key role of DR5 in AD was suggested by data showing a significant increase of DR5 receptor in cortical slices of AD brain. Thus, these findings may give intracellular TRAIL pathway a role in AD pathophysiology, making DR5 receptor a possible candidate as a pharmacological target.

  4. Chronic blockade of CB(1) receptors reverses startle gating deficits and associated neurochemical alterations in rats reared in isolation.

    PubMed

    Zamberletti, E; Piscitelli, F; Cadeddu, F; Rubino, T; Fratta, W; Fadda, P; Di Marzo, V; Parolaro, D

    2012-12-01

    Pharmacological interventions aimed at restoring the endocannabinoid system functionality have been proposed as potential tools in the treatment of schizophrenia. Based on our previous results suggesting a potential antipsychotic-like profile of the CB(1) receptor inverse agonist/antagonist, AM251, here we further investigated the effect of chronic AM251 administration on the alteration of the sensorimotor gating functions and endocannabinoid levels induced by isolation rearing in rats. Using the post-weaning social isolation rearing model, we studied its influence on sensorimotor gating functions through the PPI paradigm. The presence of alterations in the endocannabinoid levels as well as in dopamine and glutamate receptor densities was explored in specific brain regions following isolation rearing. The effect of chronic AM251 administration on PPI response and the associated biochemical alterations was assessed. The disrupted PPI response in isolation-reared rats was paralleled by significant alterations in 2-AG content and dopamine and glutamate receptor densities in specific brain regions. Chronic AM251 completely restored normal PPI response in isolated rats. This behavioural recovery was paralleled by the normalization of 2-AG levels in all the brain areas analysed. Furthermore, AM251 partially antagonized isolation-induced changes in dopamine and glutamate receptors. These results demonstrate the efficacy of chronic AM251 treatment in the recovery of isolation-induced disruption of PPI. Moreover, AM251 counteracted the imbalances in the endocannabinoid content, specifically 2-AG levels, and partially reversed the alterations in dopamine and glutamate systems associated with the disrupted behaviour. Together, these findings support the potential antipsychotic-like activity of CB(1) receptor blockade. This article is part of a themed section on Cannabinoids. To view the other articles in this section visit http://dx.doi.org/10.1111/bph.2012.167.issue-8.

  5. Measuring specific receptor binding of a PET radioligand in human brain without pharmacological blockade: The genomic plot

    PubMed Central

    Veronese, Mattia; Zanotti-Fregonara, Paolo; Rizzo, Gaia; Bertoldo, Alessandra; Innis, Robert B.; Turkheimer, Federico E.

    2016-01-01

    PET studies allow in vivo imaging of the density of brain receptor species. The PET signal, however, is the sum of the fraction of radioligand that is specifically bound to the target receptor and the non-displaceable fraction (i.e. the non-specifically bound radioligand plus the free ligand in tissue). Therefore, measuring the non-displaceable fraction, which is generally assumed to be constant across the brain, is a necessary step to obtain regional estimates of the specific fractions. The nondisplaceable binding can be directly measured if a reference region, i.e. a region devoid of any specific binding, is available. Many receptors are however widely expressed across the brain, and a true reference region is rarely available. In these cases, the nonspecific binding can be obtained after competitive pharmacological blockade, which is often contraindicated in humans. In this work we introduce the genomic plot for estimating the nondisplaceable fraction using baseline scans only. The genomic plot is a transformation of the Lassen graphical method in which the brain maps of mRNA transcripts of the target receptor obtained from the Allen brain atlas are used as a surrogate measure of the specific binding. Thus, the genomic plot allows the calculation of the specific and nondisplaceable components of radioligand uptake without the need of pharmacological blockade. We first assessed the statistical properties of the method with computer simulations. Then we sought ground-truth validation using human PET datasets of seven different neuroreceptor radioligands, where nonspecific fractions were either obtained separately using drug displacement or available from a true reference region. The population nondisplaceable fractions estimated by the genomic plot were very close to those measured by actual human blocking studies (mean relative difference between 2% and 7%). However, these estimates were valid only when mRNA expressions were predictive of protein levels (i

  6. Measuring specific receptor binding of a PET radioligand in human brain without pharmacological blockade: The genomic plot.

    PubMed

    Veronese, Mattia; Zanotti-Fregonara, Paolo; Rizzo, Gaia; Bertoldo, Alessandra; Innis, Robert B; Turkheimer, Federico E

    2016-04-15

    PET studies allow in vivo imaging of the density of brain receptor species. The PET signal, however, is the sum of the fraction of radioligand that is specifically bound to the target receptor and the non-displaceable fraction (i.e. the non-specifically bound radioligand plus the free ligand in tissue). Therefore, measuring the non-displaceable fraction, which is generally assumed to be constant across the brain, is a necessary step to obtain regional estimates of the specific fractions. The nondisplaceable binding can be directly measured if a reference region, i.e. a region devoid of any specific binding, is available. Many receptors are however widely expressed across the brain, and a true reference region is rarely available. In these cases, the nonspecific binding can be obtained after competitive pharmacological blockade, which is often contraindicated in humans. In this work we introduce the genomic plot for estimating the nondisplaceable fraction using baseline scans only. The genomic plot is a transformation of the Lassen graphical method in which the brain maps of mRNA transcripts of the target receptor obtained from the Allen brain atlas are used as a surrogate measure of the specific binding. Thus, the genomic plot allows the calculation of the specific and nondisplaceable components of radioligand uptake without the need of pharmacological blockade. We first assessed the statistical properties of the method with computer simulations. Then we sought ground-truth validation using human PET datasets of seven different neuroreceptor radioligands, where nonspecific fractions were either obtained separately using drug displacement or available from a true reference region. The population nondisplaceable fractions estimated by the genomic plot were very close to those measured by actual human blocking studies (mean relative difference between 2% and 7%). However, these estimates were valid only when mRNA expressions were predictive of protein levels (i

  7. Blockade of 5-HT7 receptors reduces tactile allodynia in the rat.

    PubMed

    Amaya-Castellanos, Evelyn; Pineda-Farias, Jorge B; Castañeda-Corral, Gabriela; Vidal-Cantú, Guadalupe C; Murbartián, Janet; Rocha-González, Héctor I; Granados-Soto, Vinicio

    2011-10-01

    This study assessed the role of systemic and spinal 5-HT(7) receptors on rats submitted to spinal nerve injury. In addition, the 5-HT(7) receptors level in dorsal root ganglion and spinal cord was also determined. Tactile allodynia was induced by L5/L6 spinal nerve ligation. Systemic (0.01-10mg/kg) or spinal (0.3-30 μg) administration of the selective 5-HT(7) receptor antagonist SB-269970 but not vehicle reduced in a dose-dependent manner established tactile allodynia. This effect was maintained for about 6h. SB-269970 was more potent and effective by the spinal administration route than through systemic injection. Spinal nerve ligation reduced expression of 5-HT(7) receptors in the ipsilateral but not contralateral dorsal root ganglia. Moreover, 5-HT(7) receptor levels were lower in the ipsilateral dorsal spinal cord of neuropathic rats compared to naïve and sham rats. No changes in the receptor levels were observed in the contralateral dorsal spinal cord and in both regions of the ventral spinal cord. Data suggest that spinal 5-HT(7) receptors play a pronociceptive role in neuropathic rats. Results also indicate that spinal nerve injury leads to a reduced 5-HT(7) receptors level in pain processing-related areas which may result from its nociceptive role in this model. Data suggest that selective 5-HT(7) receptor antagonists may function as analgesics in nerve injury pain states.

  8. P2Y12 Receptor Localizes in the Renal Collecting Duct and Its Blockade Augments Arginine Vasopressin Action and Alleviates Nephrogenic Diabetes Insipidus

    PubMed Central

    Zhang, Yue; Peti-Peterdi, Janos; Müller, Christa E.; Carlson, Noel G.; Baqi, Younis; Strasburg, David L.; Heiney, Kristina M.; Villanueva, Karie; Kohan, Donald E.

    2015-01-01

    P2Y12 receptor (P2Y12-R) signaling is mediated through Gi, ultimately reducing cellular cAMP levels. Because cAMP is a central modulator of arginine vasopressin (AVP)-induced water transport in the renal collecting duct (CD), we hypothesized that if expressed in the CD, P2Y12-R may play a role in renal handling of water in health and in nephrogenic diabetes insipidus. We found P2Y12-R mRNA expression in rat kidney, and immunolocalized its protein and aquaporin-2 (AQP2) in CD principal cells. Administration of clopidogrel bisulfate, an irreversible inhibitor of P2Y12-R, significantly increased urine concentration and AQP2 protein in the kidneys of Sprague–Dawley rats. Notably, clopidogrel did not alter urine concentration in Brattleboro rats that lack AVP. Clopidogrel administration also significantly ameliorated lithium-induced polyuria, improved urine concentrating ability and AQP2 protein abundance, and reversed the lithium-induced increase in free-water excretion, without decreasing blood or kidney tissue lithium levels. Clopidogrel administration also augmented the lithium-induced increase in urinary AVP excretion and suppressed the lithium-induced increase in urinary nitrates/nitrites (nitric oxide production) and 8-isoprostane (oxidative stress). Furthermore, selective blockade of P2Y12-R by the reversible antagonist PSB-0739 in primary cultures of rat inner medullary CD cells potentiated the expression of AQP2 and AQP3 mRNA, and cAMP production induced by dDAVP (desmopressin). In conclusion, pharmacologic blockade of renal P2Y12-R increases urinary concentrating ability by augmenting the effect of AVP on the kidney and ameliorates lithium-induced NDI by potentiating the action of AVP on the CD. This strategy may offer a novel and effective therapy for lithium-induced NDI. PMID:25855780

  9. P2Y12 Receptor Localizes in the Renal Collecting Duct and Its Blockade Augments Arginine Vasopressin Action and Alleviates Nephrogenic Diabetes Insipidus.

    PubMed

    Zhang, Yue; Peti-Peterdi, Janos; Müller, Christa E; Carlson, Noel G; Baqi, Younis; Strasburg, David L; Heiney, Kristina M; Villanueva, Karie; Kohan, Donald E; Kishore, Bellamkonda K

    2015-12-01

    P2Y12 receptor (P2Y12-R) signaling is mediated through Gi, ultimately reducing cellular cAMP levels. Because cAMP is a central modulator of arginine vasopressin (AVP)-induced water transport in the renal collecting duct (CD), we hypothesized that if expressed in the CD, P2Y12-R may play a role in renal handling of water in health and in nephrogenic diabetes insipidus. We found P2Y12-R mRNA expression in rat kidney, and immunolocalized its protein and aquaporin-2 (AQP2) in CD principal cells. Administration of clopidogrel bisulfate, an irreversible inhibitor of P2Y12-R, significantly increased urine concentration and AQP2 protein in the kidneys of Sprague-Dawley rats. Notably, clopidogrel did not alter urine concentration in Brattleboro rats that lack AVP. Clopidogrel administration also significantly ameliorated lithium-induced polyuria, improved urine concentrating ability and AQP2 protein abundance, and reversed the lithium-induced increase in free-water excretion, without decreasing blood or kidney tissue lithium levels. Clopidogrel administration also augmented the lithium-induced increase in urinary AVP excretion and suppressed the lithium-induced increase in urinary nitrates/nitrites (nitric oxide production) and 8-isoprostane (oxidative stress). Furthermore, selective blockade of P2Y12-R by the reversible antagonist PSB-0739 in primary cultures of rat inner medullary CD cells potentiated the expression of AQP2 and AQP3 mRNA, and cAMP production induced by dDAVP (desmopressin). In conclusion, pharmacologic blockade of renal P2Y12-R increases urinary concentrating ability by augmenting the effect of AVP on the kidney and ameliorates lithium-induced NDI by potentiating the action of AVP on the CD. This strategy may offer a novel and effective therapy for lithium-induced NDI.

  10. Blockade of kinin B(1) receptor reverses plasma fatty acids composition changes and body and tissue fat gain in a rat model of insulin resistance.

    PubMed

    Dias, J P; Couture, R

    2012-03-01

    Kinin B(1) receptor (B(1) R) contributes to insulin resistance through a mechanism involving oxidative stress. This study examined the effect of B(1) R blockade on the changes in plasma fatty acids composition, body and tissue fat mass and adipose tissue inflammation that influence insulin resistance. Sprague-Dawley rats were fed with 10% D-glucose or tap water (Control) for 13 weeks and during the last week, rats were administered the B(1) R antagonist SSR240612 (10 mg/kg/day, gavage) or vehicle. The following parameters were assessed: plasma fatty acids (by gas chromatography), body composition (by EchoMRI), metabolic hormone levels (by radioimmunoassay), expression of B(1) R and inflammatory markers in adipose tissue (by Western blot and qRT-PCR). Glucose feeding significantly increased plasma levels of glucose, insulin, leptin, palmitoleic acid (16:1n-7), oleic acid (18:1n-9), Δ6 and Δ9 desaturases while linoleic acid (18:2n-6), arachidonic acid (20:4n-6) and Δ5 desaturase were decreased. SSR240612 reduced plasma levels of insulin, glucose, the homeostasis model assessment index of insulin resistance, palmitoleic acid and n-7 family. Alterations of Δ5, Δ6 and Δ9 desaturases were normalized by SSR240612. The B(1) R antagonist also reversed the enhancing effect of glucose feeding on whole body and epididymal fat mass and on the expression of macrophage CD68, interleukin-1β, tumour necrosis factor-α and inducible nitric oxide synthase in retroperitoneal adipose tissue. B(1) R protein and mRNA were not detected in retroperitoneal adipose tissue. Insulin resistance in glucose-fed rats is associated with low state inflammation in adipose tissue and plasma fatty acids changes which are reversed by B(1) R blockade. These beneficial effects may contribute to insulin sensitivity improvement and the prevention of obesity. © 2011 Blackwell Publishing Ltd.

  11. Dual A1/A2B Receptor Blockade Improves Cardiac and Renal Outcomes in a Rat Model of Heart Failure with Preserved Ejection Fraction

    PubMed Central

    Tofovic, Stevan P.; Salah, Eman M.; Smits, Glenn J.; Whalley, Eric T.; Ticho, Barry; Deykin, Aaron

    2016-01-01

    Heart failure with preserved ejection fraction (HFpEF) is prevalent and often accompanied by metabolic syndrome. Current treatment options are limited. Here, we test the hypothesis that combined A1/A2B adenosine receptor blockade is beneficial in obese ZSF1 rats, an animal model of HFpEF with metabolic syndrome. The combined A1/A2B receptor antagonist 3-[4-(2,6-dioxo-1,3-dipropyl-7H-purin-8-yl)-1-bicyclo[2.2.2]octanyl]propanoic acid (BG9928) was administered orally (10 mg/kg/day) to obese ZSF1 rats (n = 10) for 24 weeks (from 20 to 44 weeks of age). Untreated ZSF1 rats (n = 9) served as controls. After 24 weeks of administration, BG9928 significantly lowered plasma triglycerides (in mg/dl: control group, 4351 ± 550; BG9928 group, 2900 ± 551) without adversely affecting plasma cholesterol or activating renin release. BG9928 significantly decreased 24-hour urinary glucose excretion (in mg/kg/day: control group, 823 ± 179; BG9928 group, 196 ± 80) and improved oral glucose tolerance, polydipsia, and polyuria. BG9928 significantly augmented left ventricular diastolic function in association with a reduction in cardiac vasculitis and cardiac necrosis. BG9928 significantly reduced 24-hour urinary protein excretion (in mg/kg/day: control group, 1702 ± 263; BG9928 group, 1076 ± 238), and this was associated with a reduction in focal segmental glomerulosclerosis, tubular atrophy, tubular dilation, and deposition of proteinaceous material in the tubules. These findings show that, in a model of HFpEF with metabolic syndrome, A1/A2B receptor inhibition improves hyperlipidemia, exerts antidiabetic actions, reduces HFpEF, improves cardiac histopathology, and affords renal protection. We conclude that chronic administration of combined A1/A2B receptor antagonists could be beneficial in patients with HFpEF, in particular those with comorbidities such as obesity, diabetes, and dyslipidemias. PMID:26585572

  12. NK cell killing of AML and ALL blasts by Killer-Immunoglobulin Receptor (KIR) negative NK cells after NKG2A and LIR-1 blockade

    PubMed Central

    Godal, Robert; Bachanova, Veronika; Gleason, Michelle; McCullar, Valarie; Yun, Gong H.; Cooley, Sarah; Verneris, Michael R.; McGlave, Philip B.; Miller, Jeffrey S.

    2010-01-01

    Although NK cell alloreactivity has been dominated by studies of KIR, we hypothesized that NKG2A and LIR-1, present on 53±13% and 36±18% of normal NK cells, plays a role in NK cell killing of primary leukemia targets. KIR− cells, which comprise nearly half of the circulating NK cell population, exhibited tolerance to primary leukemia targets, suggesting signaling through other inhibitory receptors. Both AML and ALL targets could be rendered susceptible to lysis by fresh resting KIR− NK cells when inhibitory receptor-MHC class I interactions were blocked by pan-HLA antibodies demonstrating that these cells were functionally competent. Blockade of a single inhibitory receptor resulted in slight increases in killing, while combined LIR-1 and NKG2A blockade consistently resulted in increased NK cell cytotoxicity. Dual blockade of NKG2A and LIR-1 led to significant killing of targets by resting KIR− NK cells showing that this population is not hyporesponsive. Together these results suggest that alloreactivity of a significant fraction of KIR− NK cells is determined by NKG2A and LIR-1. Thus strategies to interrupt NKG2A and LIR-1 in combination with anti-KIR blockade hold promise for exploiting NK cell therapy in acute leukemia. PMID:20139023

  13. Effect of blockade of postsynaptic H1 or H2 receptors or activation of presynaptic H3 receptors on catecholamine-induced stimulation of ACTH and prolactin secretion.

    PubMed

    Willems, E; Knigge, U; Jorgensen, H; Kjaer, A; Warberg, J

    2000-06-01

    The effect of inhibition of the neuronal histaminergic system by blockade of postsynaptic H1 or H2 receptors or activation of presynaptic H3 autoreceptors on the ACTH and prolactin responses to the catecholamines epinephrine and norepinephrine was investigated in conscious male rats. Intracerebroventricular infusion of epinephrine and norepinephrine stimulated ACTH and prolactin secretion. Prior intracerebroventricular infusion of the H1 receptor antagonist, mepyramine, or the H2 receptor antagonist, cimetidine, had no effect on the ACTH response to epinephrine or norepinephrine, while these responses were inhibited by pretreatment with the H3 receptor agonist, imetit. The prolactin response to norepinephrine was significantly inhibited by pretreatment with mepyramine, cimetidine or imetit whereas the three histaminergic compounds had no effect on the prolactin response to epinephrine. The findings suggest that the histaminergic system exerts a mediating or permissive action on the norepinephrine-induced stimulation of prolactin secretion, whereas an intact histaminergic system may not be required for catecholamines to stimulate ACTH secretion. The inhibitory effect of imetit on catecholamine-induced release of ACTH may be due to an activation of H3 receptors located presynaptically on non-histaminergic neurons, e.g. aminergic neurons. The study further indicates an important role of histamine in the neuroendocrine regulation of prolactin secretion.

  14. Structure-activity relationship of reversible cholinesterase inhibitors: activation, channel blockade and stereospecificity of the nicotinic acetylcholine receptor-ion channel complex.

    PubMed

    Albuquerque, E X; Aracava, Y; Cintra, W M; Brossi, A; Schönenberger, B; Deshpande, S S

    1988-01-01

    1. We have shown that all cholinesterase (ChE) inhibitors, in addition to their well-known anti-ChE activity, have multiple effects on the nicotinic acetylcholine receptor-ion channel (AChR) macromolecule resulting from interactions with the agonist recognition site and with sites located at the ion channel component. Activation, competitive antagonism and different types of noncompetitive blockade occurring at similar concentration ranges and contributing in different proportions result in complex and somewhat unpredictable alterations in AChR function. The question is now raised as to how each effect of these compounds contributes to their antidotal property against organophosphorus (OP) poisoning, and what set of actions makes one reversible ChE inhibitor a better antidote. Many lines of evidence support the importance of direct interactions with various sites on the AChR: 1) morphological and toxicological studies with (+) physostigmine showed that anti-ChE activity is not essential to protect animals against toxicity by irreversible ChE inhibitors; 2) (-)physostigmine is far more effective against OP poisoning; 3) open channel blockers such as mecamylamine with no significant anti-ChE activity enhance the protective action of (-)physostigmine; 4) neostigmine, pyridostigmine, (-)physostigmine and (+)physostigmine showed qualitatively and quantitatively distinct toxicity and damage to endplate morphology and function. 2. In prophylaxis and during the very early phase of OP poisoning, carbamates, especially (-)physostigmine combined with mecamylamine and atropine, could protect almost 100% of the animals exposed to multiple lethal doses of OPs. Electrophysiological data showed that (-)physostigmine, among several reversible ChE inhibitors, showed greater potency in depressing both endplate current (EPC) peak amplitude and tau EPC. Therefore, concerning neuromuscular transmission, it seems that the higher the potency of a drug in reducing endplate permeability

  15. Partial blockade of nicotinic acetylcholine receptors improves the counterregulatory response to hypoglycemia in recurrently hypoglycemic rats

    PubMed Central

    LaGamma, Edmund F.; Kirtok, Necla; Chan, Owen

    2014-01-01

    Recurrent exposure to hypoglycemia can impair the normal counterregulatory hormonal responses that guard against hypoglycemia, leading to hypoglycemia unawareness. This pathological condition known as hypoglycemia-associated autonomic failure (HAAF) is the main adverse consequence that prevents individuals with type 1 diabetes mellitus from attaining the long-term health benefits of tight glycemic control. The underlying molecular mechanisms responsible for the progressive loss of the epinephrine response to subsequent bouts of hypoglycemia, a hallmark sign of HAAF, are largely unknown. Normally, hypoglycemia triggers both the release and biosynthesis of epinephrine through activation of nicotinic acetylcholine receptors (nAChR) on the adrenal glands. We hypothesize that excessive cholinergic stimulation may contribute to impaired counterregulation. Here, we tested whether administration of the nAChR partial agonist cytisine to reduce postganglionic synaptic activity can preserve the counterregulatory hormone responses in an animal model of HAAF. Compared with nicotine, cytisine has limited efficacy to activate nAChRs and stimulate epinephrine release and synthesis. We evaluated adrenal catecholamine production and secretion in nondiabetic rats subjected to two daily episodes of hypoglycemia for 3 days, followed by a hyperinsulinemic hypoglycemic clamp on day 4. Recurrent hypoglycemia decreased epinephrine responses, and this was associated with suppressed TH mRNA induction (a measure of adrenal catecholamine synthetic capacity). Treatment with cytisine improved glucagon responses as well as epinephrine release and production in recurrently hypoglycemic animals. These data suggest that pharmacological manipulation of ganglionic nAChRs may be promising as a translational adjunctive therapy to avoid HAAF in type 1 diabetes mellitus. PMID:25117409

  16. Glucose inhibition of epinephrine stimulation of hepatic gluconeogenesis by blockade of the alpha-receptor function.

    PubMed

    Kneer, N M; Bosch, A L; Clark, M G; Lardy, H A

    1974-11-01

    For isolated rat hepatocytes, glucagon, 3':5'-cyclic AMP, 3':5'-cyclic GMP, and epinephrine stimulate the rate of gluconeogenesis from substrates not involving pathways of mitochondrial metabolism. From estimation of the rates of glucose formation, fructose 6-phosphate phosphorylation, and lactate and pyruvate formation it is concluded that epinephrine and 3':5'-cyclic GMP stimulate gluconeogenesis from either galactose or fructose by influencing the rate of reactions involving fructose 6-phosphate in a manner similar to that already reported for glucagon and 3':5'-cyclic AMP. Each agent acts to inhibit flux through phosphofructokinase (EC 2.7.1.11) and enhance flux through fructose diphosphatase (EC 3.1.3.11), resulting in the re-direction of carbon from lactate and pyruvate formation to glucose synthesis. In addition to 3':5'-cyclic GMP, dibutyryl 3':5'-cyclic GMP, 8-bromo 3':5'-cyclic GMP, 8-benzyl-thio 3':5'-cyclic GMP and 8-(4-chlorophenyl)thio 3':5'-cyclic GMP stimulate glucose formation and inhibit lactate and pyruvate formation from galactose. Guanosine monophosphate and 2':3'-cyclic GMP are inactive. As the stimulatory effect of epinephrine is inhibited by phenoxybenzamine and not by propranolol, and is not simulated by isoproterenol, it is concluded that catecholamine activity is expressed through the alpha-receptor. Increased extracellular glucose concentration (>10 mM) decreases the stimulatory effect of epinephrine, 3':5'-cyclic GMP, and partially that of 3':5'-cyclic AMP but does not alter the efficacy of glucagon.

  17. Effects of glucagon-like peptide-1 receptor stimulation and blockade on food consumption and body weight in rats treated with a cannabinoid CB1 receptor agonist WIN 55,212-2.

    PubMed

    Radziszewska, Elżbieta; Bojanowska, Ewa

    2013-01-01

    Glucagon-like peptide-1 (GLP-1) and endocannabinoids are involved in appetite control. Recently we have demonstrated that cannabinoid (CB)1 receptor antagonist and GLP-1 receptor agonist synergistically suppress food intake in the rat. The aim of the present study was to determine the effects of GLP-1 receptor stimulation or blockade on feeding behavior in rats treated with WIN 55,212-2, a CB1 receptor agonist. Experiments were performed on adult male Wistar rats. In the first experiment the effects of increasing doses (0.5-4.0 mg/kg) of WIN 55,212-2 injected intraperitoneally on 24-hour food consumption were tested. In further experiments a GLP-1 receptor antagonist, exendin (9-39), and WIN 55,212-2 or a GLP-1 receptor agonist, exendin-4, and WIN 55,212-2 were injected intraperitoneally at subthreshold doses (that alone did not change food intake and body weight) to investigate whether these agents may interact to affect food intake in rats. WIN 55,212-2 administered at low doses (0.5-2 mg/kg) did not markedly change 24-hour food consumption; however, at the highest dose, daily food intake was inhibited. Combined administration of WIN 55,212-2 and exendin (9-39) did not change the amount of food consumed compared to either the control group or to each agent injected alone. Combined injection of WIN 55,212-2 and exendin-4 at subthreshold doses resulted in a significant decrease in food intake and body weight in rats. Stimulation of the peripheral CB1 receptor by its agonist WIN 55,212-2 can induce anorexigenic effects or potentiate, even at a subthreshold dose, the effects of exendin-4, a known anorectic agent. Hence, this dual action of the cannabinoid system should be considered in the medical use of CB1 agonists.

  18. Decreased Brain Neurokinin-1 Receptor Availability in Chronic Tennis Elbow

    PubMed Central

    Linnman, Clas; Catana, Ciprian; Svärdsudd, Kurt; Appel, Lieuwe; Engler, Henry; Långström, Bengt; Sörensen, Jens; Furmark, Tomas; Fredrikson, Mats; Borsook, David; Peterson, Magnus

    2016-01-01

    Substance P is released in painful and inflammatory conditions, affecting both peripheral processes and the central nervous system neurokinin 1 (NK1) receptor. There is a paucity of data on human brain alterations in NK1 expression, how this system may be affected by treatment, and interactions between central and peripheral tissue alterations. Ten subjects with chronic tennis elbow (lateral epicondylosis) were selected out of a larger (n = 120) randomized controlled trial evaluating graded exercise as a treatment for chronic tennis elbow (lateral epicondylosis). These ten subjects were examined by positron emission tomography (PET) with the NK1-specific radioligand 11C-GR205171 before, and eight patients were followed up after treatment with graded exercise. Brain binding in the ten patients before treatment, reflecting NK1-receptor availability (NK1-RA), was compared to that of 18 healthy subjects and, longitudinally, to the eight of the original ten patients that agreed to a second PET examination after treatment. Before treatment, patients had significantly lower NK1-RA in the insula, vmPFC, postcentral gyrus, anterior cingulate, caudate, putamen, amygdala and the midbrain but not the thalamus and cerebellum, with the largest difference in the insula contralateral to the injured elbow. No significant correlations between brain NK1-RA and pain, functional severity, or peripheral NK1-RA in the affected limb were observed. In the eight patients examined after treatment, pain ratings decreased in everyone, but there were no significant changes in NK1-RA. These findings indicate a role for the substance P (SP) / NK1 receptor system in musculoskeletal pain and tissue healing. As neither clinical parameters nor successful treatment response was reflected in brain NK1-RA after treatment, this may reflect the diverse function of the SP/NK1 system in CNS and peripheral tissue, or a change too small or slow to capture over the three-month treatment. PMID:27658244

  19. Mechanism of A2 adenosine receptor activation. I. Blockade of A2 adenosine receptors by photoaffinity labeling

    SciTech Connect

    Lohse, M.J.; Klotz, K.N.; Schwabe, U.

    1991-04-01

    It has previously been shown that covalent incorporation of the photoreactive adenosine derivative (R)-2-azido-N6-p-hydroxy-phenylisopropyladenosine ((R)-AHPIA) into the A1 adenosine receptor of intact fat cells leads to a persistent activation of this receptor, resulting in a reduction of cellular cAMP levels. In contrast, covalent incorporation of (R)-AHPIA into human platelet membranes, which contain only stimulatory A2 adenosine receptors, reduces adenylate cyclase stimulation via these receptors. This effect of (R)-AHPIA is specific for the A2 receptor and can be prevented by the adenosine receptor antagonist theophylline. Binding studies indicate that up to 90% of A2 receptors can be blocked by photoincorporation of (R)-AHPIA. However, the remaining 10-20% of A2 receptors are sufficient to mediate an adenylate cyclase stimulation of up to 50% of the control value. Similarly, the activation via these 10-20% of receptors occurs with a half-life that is only 2 times longer than that in control membranes. This indicates the presence of a receptor reserve, with respect to both the extent and the rate of adenylate cyclase stimulation. These observations require a modification of the models of receptor-adenylate cyclase coupling.

  20. The blockade of transient receptor potential ankirin 1 (TRPA1) signalling mediates antidepressant- and anxiolytic-like actions in mice

    PubMed Central

    de Moura, Juliana Cavalcante; Noroes, Maíra Macedo; Rachetti, Vanessa de Paula Soares; Soares, Bruno Lobão; Preti, Delia; Nassini, Romina; Materazzi, Serena; Marone, Ilaria Maddalena; Minocci, Daiana; Geppetti, Pierangelo; Gavioli, Elaine Cristina; André, Eunice

    2014-01-01

    Background and Purpose Transient receptor potential vanilloid 1 (TRPV1) and TRP ankyrin 1 (TRPA1) are involved in many biological processes, including nociception and hyperalgesia. Whereas the involvement of TRPV1 in psychiatric disorders such as anxiety and depression has been reported, little is known regarding the role of TRPA1 in these conditions. Experimental Approach We investigated the role of TRPA1 in mice models of depression [forced swimming test (FST)] and anxiety [elevated plus maze (EPM) test]. Key Results Administration of the TRPA1 antagonist (HC030031, 30 nmol in 2 μL, i.c.v.) reduced immobility time in the FST. Similar results were obtained after oral administration of HC030031 (30–300 mg·kg−1). The reduction in immobility time in FST induced by HC030031 (100 mg·kg−1) was completely prevented by pretreatment with TRPA1 agonist, cinnamaldehyde (50 mg·kg−1, p.o.), which per se was inactive. In the EPM test, pretreatment with cinnamaldehyde (50 mg·kg−1, p.o.), which per se did not affect behaviour response, prevented the anxiolytic-like effect (increased open arm exploration) evoked by TRPA1 blockade (HC030031, 100 mg·kg−1, p.o.). Treatment with either cinnamaldehyde or HC030031 did not affect spontaneous ambulation. Furthermore, TRPA1-deficient mice showed anxiolytic- and antidepressant-like phenotypes in the FST and EPM test respectively. Conclusion and Implications The present findings indicate that genetic deletion or pharmacological blockade of TRPA1 produces inhibitory activity in mouse models of anxiety and depression. These results imply that TRPA1 exerts tonic control, promoting anxiety and depression, and that TRPA1 antagonism has potential as an innovative strategy for the treatment of anxiety and mood disorders. PMID:24846744

  1. Nogo receptor blockade overcomes remyelination failure after white matter stroke and stimulates functional recovery in aged mice

    PubMed Central

    Sozmen, Elif G.; Rosenzweig, Shira; Llorente, Irene L.; DiTullio, David J.; Machnicki, Michal; Vinters, Harry V.; Havton, Lief A.; Giger, Roman J.; Hinman, Jason D.

    2016-01-01

    White matter stroke is a distinct stroke subtype, accounting for up to 25% of stroke and constituting the second leading cause of dementia. The biology of possible tissue repair after white matter stroke has not been determined. In a mouse stroke model, white matter ischemia causes focal damage and adjacent areas of axonal myelin disruption and gliosis. In these areas of only partial damage, local white matter progenitors respond to injury, as oligodendrocyte progenitors (OPCs) proliferate. However, OPCs fail to mature into oligodendrocytes (OLs) even in regions of demyelination with intact axons and instead divert into an astrocytic fate. Local axonal sprouting occurs, producing an increase in unmyelinated fibers in the corpus callosum. The OPC maturation block after white matter stroke is in part mediated via Nogo receptor 1 (NgR1) signaling. In both aged and young adult mice, stroke induces NgR1 ligands and down-regulates NgR1 inhibitors during the peak OPC maturation block. Nogo ligands are also induced adjacent to human white matter stroke in humans. A Nogo signaling blockade with an NgR1 antagonist administered after stroke reduces the OPC astrocytic transformation and improves poststroke oligodendrogenesis in mice. Notably, increased white matter repair in aged mice is translated into significant poststroke motor recovery, even when NgR1 blockade is provided during the chronic time points of injury. These data provide a perspective on the role of NgR1 ligand function in OPC fate in the context of a specific and common type of stroke and show that it is amenable to systemic intervention to promote recovery. PMID:27956620

  2. Angiotensin type 1 receptor resistance to blockade in the opossum proximal tubule cell due to variations in the binding pocket.

    PubMed

    Nistala, Ravi; Andresen, Bradley T; Pulakat, Lakshmi; Meuth, Alex; Sinak, Catherine; Mandavia, Chirag; Thekkumkara, Thomas; Speth, Robert C; Whaley-Connell, Adam; Sowers, James R

    2013-04-15

    Blockade of the angiotensin (ANG) II receptor type 1 (AT(1)R) with angiotensin receptor blockers (ARBs) is widely used in the treatment of hypertension. However, ARBs are variably effective in reducing blood pressure, likely due, in part, to polymorphisms in the ARB binding pocket of the AT(1)R. Therefore, we need a better understanding of variations/polymorphisms that alter binding of ARBs in heterogeneous patient populations. The opossum proximal tubule cell (OKP) line is commonly used in research to evaluate renal sodium handling and therefore blood pressure. Investigating this issue, we found natural sequence variations in the opossum AT(1)R paralleling those observed in the human AT(1)R. Therefore, we posited that these sequence variations may explain ARB resistance. We demonstrate that OKP cells express AT(1)R mRNA, bind (125)I-labeled ANG II, and exhibit ANG II-induced phosphorylation of Jak2. However, Jak2 phosphorylation is not inhibited by five different ARBs commonly used to treat hypertension. Additionally, nonradioactive ANG II competes (125)I-ANG II efficiently, whereas a 10-fold molar excess of olmesartan and the ANG II receptor type 2 blocker PD-123319 is unable to block (125)I-ANG II binding. In contrast, ANG II binding to OKP cells stably expressing rat AT(1A)Rs, which have a conserved AT(1)R-binding pocket with human AT(1)R, is efficiently inhibited by olmesartan. A novel observation was that resistance to ARB binding to opossum AT(1)Rs correlates with variations from the human receptor at positions 108, 163, 192, and 198 within the ARB-binding pocket. These observations highlight the potential utility of evaluating AT(1)R polymorphisms within the ARB-binding pocket in various hypertensive populations.

  3. Effect of acute aerobic exercise and histamine receptor blockade on arterial stiffness in African Americans and Caucasians.

    PubMed

    Yan, Huimin; Ranadive, Sushant M; Lane-Cordova, Abbi D; Kappus, Rebecca M; Behun, Michael A; Cook, Marc D; Woods, Jeffrey A; Wilund, Kenneth R; Baynard, Tracy; Halliwill, John R; Fernhall, Bo

    2017-02-01

    African Americans (AA) exhibit exaggerated central blood pressure (BP) and arterial stiffness measured by pulse wave velocity (PWV) in response to an acute bout of maximal exercise compared with Caucasians (CA). However, whether potential racial differences exist in central BP, elastic, or muscular arterial distensibility after submaximal aerobic exercise remains unknown. Histamine receptor activation mediates sustained postexercise hyperemia in CA but the effect on arterial stiffness is unknown. This study sought to determine the effects of an acute bout of aerobic exercise on central BP and arterial stiffness and the role of histamine receptors, in AA and CA. Forty-nine (22 AA, 27 CA) young and healthy subjects completed the study. Subjects were randomly assigned to take either histamine receptor antagonist or control placebo. Central blood BP and arterial stiffness measurements were obtained at baseline, and at 30, 60, and 90 min after 45 min of moderate treadmill exercise. AA exhibited greater central diastolic BP, elevated brachial PWV, and local carotid arterial stiffness after an acute bout of submaximal exercise compared with CA, which may contribute to their higher risk of cardiovascular disease. Unexpectedly, histamine receptor blockade did not affect central BP or PWV in AA or CA after exercise, but it may play a role in mediating local carotid arterial stiffness. Furthermore, histamine may mediate postexercise carotid arterial dilation in CA but not in AA. These observations provide evidence that young and healthy AA exhibit an exaggerated hemodynamic response to exercise and attenuated vasodilator response compared with CA.NEW & NOTEWORTHY African Americans are at greater risk for developing cardiovascular disease than Caucasians. We are the first to show that young and healthy African Americans exhibit greater central blood pressure, elevated brachial stiffness, and local carotid arterial stiffness following an acute bout of submaximal exercise

  4. Muscarinic, but not nicotinic, acetylcholine receptor blockade in the ventral tegmental area attenuates cue-induced sucrose-seeking

    PubMed Central

    Addy, Nii A.; Nunes, Eric J.; Wickham, Robert J.

    2015-01-01

    The mesolimbic dopamine (DA) system is known to play a role in cue-mediated reward-seeking for natural rewards and drugs of abuse. Specifically, cholinergic and glutamatergic receptors in the ventral tegmental area (VTA) have been shown to regulate cue-induced drug-seeking. However, the potential role of these VTA receptors in regulating cue-induced reward seeking for natural rewards is unknown. Here, we examined whether blockade of VTA acetylcholine receptors (AChRs) and N-methyl-D-aspartate receptors (NMDARs) would alter cue-induced sucrose seeking in male Sprague-Dawley rats. Subjects underwent 10 days of sucrose self-administration training (fixed ratio 1 schedule) followed by 7 days of forced abstinence. On withdrawal day 7, rats received bilateral VTA infusion of vehicle, the muscarinic AChR antagonist scopolamine (2.4 or 24 μg/side), the nicotinic AChR antagonist mecamylamine (3 or 30 μg/side), or the NMDAR antagonist AP-5 (0.1 or 1 μg/side) immediately prior to examination of cue-induced sucrose-seeking. Scopolamine infusion led to robust attenuation, but did not completely block, sucrose-seeking behavior. In contrast, VTA administration of mecamylamine or AP-5 did not alter cue-induced sucrose-seeking. Together, the data suggest that VTA muscarinic AChRs, but not nicotinic AChRs nor NMDARs, facilitate the ability of food-associated cues to drive seeking behavior for a food reward. PMID:26026787

  5. Angiotensin type 1 receptor resistance to blockade in the opossum proximal tubule cell due to variations in the binding pocket

    PubMed Central

    Nistala, Ravi; Andresen, Bradley T.; Pulakat, Lakshmi; Meuth, Alex; Sinak, Catherine; Mandavia, Chirag; Thekkumkara, Thomas; Speth, Robert C.; Whaley-Connell, Adam

    2013-01-01

    Blockade of the angiotensin (ANG) II receptor type 1 (AT1R) with angiotensin receptor blockers (ARBs) is widely used in the treatment of hypertension. However, ARBs are variably effective in reducing blood pressure, likely due, in part, to polymorphisms in the ARB binding pocket of the AT1R. Therefore, we need a better understanding of variations/polymorphisms that alter binding of ARBs in heterogeneous patient populations. The opossum proximal tubule cell (OKP) line is commonly used in research to evaluate renal sodium handling and therefore blood pressure. Investigating this issue, we found natural sequence variations in the opossum AT1R paralleling those observed in the human AT1R. Therefore, we posited that these sequence variations may explain ARB resistance. We demonstrate that OKP cells express AT1R mRNA, bind 125I-labeled ANG II, and exhibit ANG II-induced phosphorylation of Jak2. However, Jak2 phosphorylation is not inhibited by five different ARBs commonly used to treat hypertension. Additionally, nonradioactive ANG II competes 125I-ANG II efficiently, whereas a 10-fold molar excess of olmesartan and the ANG II receptor type 2 blocker PD-123319 is unable to block 125I-ANG II binding. In contrast, ANG II binding to OKP cells stably expressing rat AT1ARs, which have a conserved AT1R-binding pocket with human AT1R, is efficiently inhibited by olmesartan. A novel observation was that resistance to ARB binding to opossum AT1Rs correlates with variations from the human receptor at positions 108, 163, 192, and 198 within the ARB-binding pocket. These observations highlight the potential utility of evaluating AT1R polymorphisms within the ARB-binding pocket in various hypertensive populations. PMID:23389452

  6. 5-HT6 receptor blockade regulates primary cilia morphology in striatal neurons.

    PubMed

    Brodsky, Matthew; Lesiak, Adam J; Croicu, Alex; Cohenca, Nathalie; Sullivan, Jane M; Neumaier, John F

    2017-04-01

    The 5-HT6 receptor has been implicated in a variety of cognitive processes including habitual behaviors, learning, and memory. It is found almost exclusively in the brain, is expressed abundantly in striatum, and localizes to neuronal primary cilia. Primary cilia are antenna-like, sensory organelles found on most neurons that receive both chemical and mechanical signals from other cells and the surrounding environment; however, the effect of 5-HT6 receptor function on cellular morphology has not been examined. We confirmed that 5-HT6 receptors were localized to primary cilia in wild-type (WT) but not 5-HT6 knockout (5-HT6KO) in both native mouse brain tissue and primary cultured striatal neurons then used primary neurons cultured from WT or 5-HT6KO mice to study the function of these receptors. Selective 5-HT6 antagonists reduced cilia length in neurons cultured from wild-type mice in a concentration and time-dependent manner without altering dendrites, but had no effect on cilia length in 5-HT6KO cultured neurons. Varying the expression levels of heterologously expressed 5-HT6 receptors affected the fidelity of ciliary localization in both WT and 5-HT6KO neurons; overexpression lead to increasing amounts of 5-HT6 localization outside of the cilia but did not alter cilia morphology. Introducing discrete mutations into the third cytoplasmic loop of the 5-HT6 receptor greatly reduced, but did not entirely eliminate, trafficking of the 5-HT6 receptor to primary cilia. These data suggest that blocking 5-HT6 receptor activity reduces the length of primary cilia and that mechanisms that regulate trafficking of 5-HT6 receptors to cilia are more complex than previously thought. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. [Beta-1 adrenoceptor blockade decreases the firing rate to painful stimuli in spinal wide-dynamic range neurons in rats].

    PubMed

    Lamothe-Molina, Paul J; Lamothe-Molina, Pedro A; López-Ávila, Alberto

    2014-01-01

    Introducción: la epinefrina/norepinefrina inhibe la transmisión del dolor agudo; empero, no es claro el papel de los receptores beta-adrenérgicos. Por tanto, analizamos si los fármacos de estos receptores modulan la transmisión del dolor agudo mediante registro electrofisiológico unitario extracelular in vivo durante estimulación periférica dolorosa y no dolorosa en ratas. Métodos: estudio longitudinal en el que se cotejaron siete grupos de ratas: control (n = 11): solución salina (0,9 %); EPI (n = 8): 100 mcg epinefrina; agonista beta-1 (n = 8): 125 mcg dobutamina; antagonista beta-1 (n = 9): 100 mcg metoprolol; agonista beta-2 (n = 7): 100 mcg clembuterol; antagonista beta-2 (n = 8): butoxamina 100 mcg; antagonista beta-1 + EPI (n = 10): 100 mcg metoprolol + 100 mcg epinefrina. Se hizo análisis estadístico por medio de ANOVA. Resultados: La epinefrina redujo significativamente la tasa de disparo basal (RDB) en 34.1 % (p < 0.05) y la respuesta evocada por la estimulación dolorosa en 56 % (p < 0.05). No hubo cambios en la respuesta provocada por la falta de estimulación dolorosa. El antagonista beta-1 fue el único fármaco con acción beta-adrenérgica que redujo significativamente la respuesta evocada por la estimulación dolorosa en 41 % (p < 0.05). Conclusión: por primera vez un antagonista de los receptores beta-1-adrenérgicos (metoprolol) prueba ser eficaz en la reducción de la respuesta a la estimulación dolorosa en las neuronas ARD.

  8. Monoclonal antibody that inhibits infection of HeLa and rhabdomyosarcoma cells by selected enteroviruses through receptor blockade

    SciTech Connect

    Crowell, R.L.; Field, A.K.; Schleif, W.A.; Long, W.L.; Colonno, R.J.; Mapoles, J.E.; Emini, E. A.

    1986-02-01

    BALB/c mice were immunized with HeLa cells, and their spleen cells were fused with myeloma cells to produce hybridomas. Initial screening of culture fluids from 800 fusion products in a cell protection assay against coxsackievirus B3 (CB3) and the CB3-RD virus variant yielded five presumptive monoclonal antibodies with three specificities: (i) protection against CB3 on HeLa, (ii) protection against CB3-RD on rhabdomyosarcoma (RD) cells, and (iii) protection against both viruses on the respective cells. Only one of the monoclonal antibodies (with dual specificity) survived two subclonings and was studied in detail. The antibody was determined to have an immunoglobulin G2a isotype and protected cells by blockade of cellular receptors, since attachment of (/sup 35/S)methionine-labeled CB3 was inhibited by greater than 90%. The monoclonal antibody protected HeLa cells against infection by CB1, CB3, CB5, echovirus 6, and coxsackievirus A21 and RD cells against CB1-RD, CB3-RD, and CB5-Rd virus variants. The monoclonal antibody did not protect either cell type against 16 other immunotypes of picornaviruses. The monoclonal antibody produced only positive fluorescence on those cells which were protected against infection, and /sup 125/I-labeled antibody confirmed the specific binding to HeLa and RD cells. The results suggest that this monoclonal antibody possesses some of the receptor specificity of the group B coxsackieviruses.

  9. Dual motor responses elicited by ethanol in the posterior VTA: Consequences of the blockade of μ-opioid receptors.

    PubMed

    Martí-Prats, Lucía; Orrico, Alejandro; Polache, Ana; Granero, Luis

    2015-09-01

    A recent hypothesis, based on electrophysiological and behavioural findings, suggests that ethanol simultaneously exerts opposed effects on the activity of dopamine (DA) neurons in the ventral tegmental area (VTA) through two parallel mechanisms, one promoting and the other reducing the GABA release onto VTA DA neurons. In this sense, the activating effects are mediated by salsolinol, a metabolite of ethanol, acting on the μ-opioid receptors (MORs) located in VTA GABA neurons. The inhibitory effects are, however, triggered by the non-metabolized fraction of ethanol which would cause the GABAA receptors-mediated inhibition of VTA DA neurons. Since both trends tend to offset each other, only the use of appropriate pharmacological tools allows analysis of this phenomenon in depth. Herein, we present new behavioural findings supporting this hypothesis. Motor activity was evaluated in rats after intra-VTA administration of ethanol 35 nmol, an apparently ineffective dose, 24 h after the irreversible blockade of MORs in the VTA with β-FNA. Our results showed that this pre-treatment turned the initially ineffective ethanol dose into a depressant one, confirming that the activating effect of ethanol can be selectively suppressed without affecting the depressant effects mediated by the non-biotransformed fraction of ethanol. © The Author(s) 2015.

  10. Widespread Decrease of Nicotinic Acetylcholine Receptors in Parkinson's Disease

    PubMed Central

    Ichise, Masanori; Zoghbi, Sami S; Liow, Jeih-San; Ghose, Subroto; Vines, Douglass C; Sangare, Janet; Lu, Jian-Qiang; Cropley, Vanessa L; Iida, Hidehiro; Kim, Kyeong Min; Cohen, Robert M; Bara-Jimenez, William; Ravina, Bernard; Innis, Robert B

    2005-01-01

    Nicotinic acetylcholine receptors (nAChRs) have close interactions with the dopaminergic system and play critical roles in cognitive function. nAChRs were imaged in 10 non-demented Parkinson's disease (PD) patients and 15 age-matched healthy subjects using a single photon emission computed tomography ligand [123I]5-iodo-3-[2(S)-2-azetidinylmethoxy]pyridine. Using an arterial input function, we measured the total distribution volume (V; specific plus non-displaceable) as well as the delivery (K1). PD showed a widespread significant decrease (∼10%) of V in both cortical and subcortical regions without a significant change in K1. These results indicate the importance of extending the study to demented patients. PMID:16374823

  11. Chronic treatment with LY341495 decreases 5-HT(2A) receptor binding and hallucinogenic effects of LSD in mice.

    PubMed

    Moreno, José L; Holloway, Terrell; Rayannavar, Vinayak; Sealfon, Stuart C; González-Maeso, Javier

    2013-03-01

    Hallucinogenic drugs, such as lysergic acid diethylamide (LSD), mescaline and psilocybin, alter perception and cognitive processes. All hallucinogenic drugs have in common a high affinity for the serotonin 5-HT(2A) receptor. Metabotropic glutamate 2/3 (mGlu2/3) receptor ligands show efficacy in modulating the cellular and behavioral responses induced by hallucinogenic drugs. Here, we explored the effect of chronic treatment with the mGlu2/3 receptor antagonist 2S-2-amino-2-(1S,2S-2-carboxycyclopropan-1-yl)-3-(xanth-9-yl)-propionic acid (LY341495) on the hallucinogenic-like effects induced by LSD (0.24mg/kg). Mice were chronically (21 days) treated with LY341495 (1.5mg/kg), or vehicle, and experiments were carried out one day after the last injection. Chronic treatment with LY341495 down-regulated [(3)H]ketanserin binding in somatosensory cortex of wild-type, but not mGlu2 knockout (KO), mice. Head-twitch behavior, and expression of c-fos, egr-1 and egr-2, which are responses induced by hallucinogenic 5-HT(2A) agonists, were found to be significantly decreased by chronic treatment with LY341495. These findings suggest that repeated blockade of the mGlu2 receptor by LY341495 results in reduced 5-HT(2A) receptor-dependent hallucinogenic effects of LSD. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  12. In vivo blockade of thalamic GABA(B) receptors increases excitatory amino-acid levels.

    PubMed

    Nyitrai, G; Emri, Z; Crunelli, V; Kékesi, K A; Dobolyi, A; Juhász, G

    1996-12-30

    The effect of intrathalamic application of GABA(B) receptor antagonists on the basal excitatory amino-acid levels was studied using microdialysis probes implanted in the dorsal lateral geniculate nucleus and in the ventrobasal complex. In both nuclei, continuous perfusion of the GABA(B) receptor antagonist 3-aminopropyl-(diethoxymethyl)-phosphinic acid (CGP 35348) produced an increase in the extracellular concentration of aspartate and (to a lesser extent) glutamate, but no change was observed in the level of taurine, the main amino acid involved in the regulation of brain osmolarity processes. In contrast, 3-amino-2-hydroxy-2-(4-chlorophenyl)-propanesulphonic acid (2-hydroxy-saclofen), another GABA(B) receptor antagonist, failed to affect the extracellular concentration of aspartate, glutamate and taurine. Thus, the basal level of excitatory amino acids in the thalamus in vivo is under the control of CGP 35348-sensitive GABA(B) receptors.

  13. Opioid receptor blockade and warmth-liking: effects on interpersonal trust and frontal asymmetry.

    PubMed

    Schweiger, Desirée; Stemmler, Gerhard; Burgdorf, Christin; Wacker, Jan

    2014-10-01

    The emotion 'warmth-liking' (WL) associated with feelings of affection and acceptance is regularly activated in social contexts. WL has been suggested to be more closely related to the consummatory phase of post-goal attainment positive affect than to pre-goal attainment positive affect/approach motivation and to be partly mediated by brain opioids. To validate these assumptions we employed film/imagery to induce either a neutral emotional state or WL in female participants after intake of either placebo or the opioid antagonist naltrexone. Dependent variables were emotion self-report, interpersonal trust (TRUST, i.e. a behavioral indicator of WL) and frontal asymmetry (i.e. an electroencephalogram (EEG) indicator of approach motivation/behavioral activation). We found that participants reported more WL in the placebo/WL group than in the placebo/neutral group and both naltrexone groups. In addition, TRUST increased in the WL group after placebo, but not after naltrexone, and this pattern was reversed in the neutral control groups. Consequently, opioid blockade suppressed or even reversed the effects of the WL induction on the levels of self-report and behavior, respectively. In addition, we observed reduced relative left-frontal asymmetry in the WL (vs neutral) group, consistent with reduced approach motivation. Overall, these results suggest opioidergic influences on WL and TRUST and reduced approach motivation/behavioral activation for the positive emotion WL.

  14. Opioid receptor blockade and warmth-liking: effects on interpersonal trust and frontal asymmetry

    PubMed Central

    Schweiger, Desirée; Stemmler, Gerhard; Burgdorf, Christin

    2014-01-01

    The emotion ‘warmth-liking’ (WL) associated with feelings of affection and acceptance is regularly activated in social contexts. WL has been suggested to be more closely related to the consummatory phase of post-goal attainment positive affect than to pre-goal attainment positive affect/approach motivation and to be partly mediated by brain opioids. To validate these assumptions we employed film/imagery to induce either a neutral emotional state or WL in female participants after intake of either placebo or the opioid antagonist naltrexone. Dependent variables were emotion self-report, interpersonal trust (TRUST, i.e. a behavioral indicator of WL) and frontal asymmetry (i.e. an electroencephalogram (EEG) indicator of approach motivation/behavioral activation). We found that participants reported more WL in the placebo/WL group than in the placebo/neutral group and both naltrexone groups. In addition, TRUST increased in the WL group after placebo, but not after naltrexone, and this pattern was reversed in the neutral control groups. Consequently, opioid blockade suppressed or even reversed the effects of the WL induction on the levels of self-report and behavior, respectively. In addition, we observed reduced relative left-frontal asymmetry in the WL (vs neutral) group, consistent with reduced approach motivation. Overall, these results suggest opioidergic influences on WL and TRUST and reduced approach motivation/behavioral activation for the positive emotion WL. PMID:24078107

  15. The effect of blockade of dopamine receptors on the inhibition of episodic luteinizing hormone release during electrical stimulation of the arcuate nucleus in ovariectomized rats.

    PubMed

    Gallo, R V

    1978-04-01

    This study examined the possible involvement of dopamine (DA) in mediating the inhibition of episodic LH release that occurs during electrical stimulation of the arcuate nucleus (ARH) in ovariectomized rats. Animals were treated before stimulation with pimozide (1.26--2.0 mg/kg) or d-butaclamol (1 mg/kg), blockers of DA receptors, or l-butaclamol. Apomorphine, which inhibits episodic LH release by activating DA receptors, was given near the end of the experiment to determine if these receptors were blocked. ARH stimulation suppressed pulsatile LH release in six rats when DA receptors were not blocked by pimozide (as well as two in which blockade was not tested). A transient increase occurred in one other animal. When DA receptors were blocked by pimozide, stimulation of the ARH inhibited episodic LH release in nine rats, suggesting that DA may have no role in mediating this inhibition. However, because increased LH release occurred in five additional animals, as well as in one with partial receptor blockade, the possibility remains that DA may perhaps have a minor role in this inhibitory response. Although ARH stimulation increased LH release after DA receptor blockade by d-butaclamol, this effect could not be ascribed to the DA antagonist property of this agent, because elevated blood LH levels also occurred during stimulation in rats treated with l-butaclamol, in which DA receptors were not blocked. d- and l-butaclamol may possess a non-stereospecific action on a non-dopaminergic event, thus reversing the response to ARH stimulation. Finally, whether DA receptors were blocked or not by pimozide, d-, or l-butaclamol, activation of the ventromedial hypothalamic and periventricular nucleus regions suppressed episodic LH release, but did not increase LH secretion. This suggests that the region through which stimulation can inhibit, but not increase, LH release may extend in the hypothalamus to these two areas.

  16. Blockade of intra-articular adrenergic receptors increases analgesic demands for pain relief after knee surgery.

    PubMed

    Kager, Ingo; Mousa, Shaaban A; Sieper, Joachim; Stein, Christoph; Pipam, W; Likar, Rudolf

    2011-10-01

    Activation of opioid receptors on peripheral sensory nerve terminals by opioid peptides that are produced and released from immune cells can result in inhibition of inflammatory pain. This study tests the hypothesis that postoperative pain is attenuated endogenously through a local sympathetic neurotransmitter-activated release of opioids in patients undergoing knee surgery. We examined the expression of opioid peptides and adrenergic receptors in cells infiltrating inflamed synovial tissue and we hypothesized that intra-articular (i.a.) administration of the adrenergic receptor antagonist labetalol will increase postoperative analgesic consumption and/or pain intensity in these patients. In a double-blind, randomized manner, 75 patients undergoing therapeutic knee arthroscopy received i.a. placebo (20 ml saline) or labetalol (2.5 or 5 mg in 20 ml saline) at the end of surgery. Postoperative pain intensity was assessed by visual analog and verbal rating scales at rest and on exertion, and by the consumption of morphine via patient-controlled analgesia. Synovial biopsies were taken during the operation for double-immunofluorescence confocal microscopy studies. Alpha(1)- and beta(2)-adrenergic receptors were co-expressed in opioid peptide-containing cells. No significant difference was seen in pain scores, but patients receiving 2.5 mg labetalol requested significantly higher amounts of morphine. These findings are consistent with the notion that surgical stress induces sympathetically activated release of endogenous opioids from inflammatory cells and subsequent analgesia via activation of peripheral opioid receptors.

  17. Both genetic deletion and pharmacological blockade of lysophosphatidic acid LPA1 receptor results in increased alcohol consumption.

    PubMed

    Castilla-Ortega, Estela; Pavón, Francisco Javier; Sánchez-Marín, Laura; Estivill-Torrús, Guillermo; Pedraza, Carmen; Blanco, Eduardo; Suárez, Juan; Santín, Luis; Rodríguez de Fonseca, Fernando; Serrano, Antonia

    2016-04-01

    Lysophosphatidic acid species (LPA) are lipid bioactive signaling molecules that have been recently implicated in the modulation of emotional and motivational behaviors. The present study investigates the consequences of either genetic deletion or pharmacological blockade of lysophosphatidic acid receptor-1 (LPA1) in alcohol consumption. The experiments were performed in alcohol-drinking animals by using LPA1-null mice and administering the LPA1 receptor antagonist Ki16425 in both mice and rats. In the two-bottle free choice paradigm, the LPA1-null mice preferred the alcohol more than their wild-type counterparts. Whereas the male LPA1-null mice displayed this higher preference at all doses tested, the female LPA1-null mice only consumed more alcohol at 6% concentration. The male LPA1-null mice were then further characterized, showing a notably increased ethanol drinking after a deprivation period and a reduced sleep time after acute ethanol administration. In addition, LPA1-null mice were more anxious than the wild-type mice in the elevated plus maze test. For the pharmacological experiments, the acute administration of the antagonist Ki16425 consistently increased ethanol consumption in both wild-type mice and rats; while it did not modulate alcohol drinking in the LPA1-null mice and lacked intrinsic rewarding properties and locomotor effects in a conditioned place preference paradigm. In addition, LPA1-null mice exhibited a marked reduction on the expression of glutamate-transmission-related genes in the prefrontal cortex similar to those described in alcohol-exposed rodents. Results suggest a relevant role for the LPA/LPA1 signaling system in alcoholism. In addition, the LPA1-null mice emerge as a new model for genetic vulnerability to excessive alcohol drinking. The pharmacological manipulation of LPA1 receptor arises as a new target for the study and treatment of alcoholism. Copyright © 2015 Elsevier Ltd. All rights reserved.

  18. Combined blockade of angiotensin II and prorenin receptors ameliorates podocytic apoptosis induced by IgA-activated mesangial cells.

    PubMed

    Leung, Joseph C K; Chan, Loretta Y Y; Saleem, M A; Mathieson, P W; Tang, Sydney C W; Lai, Kar Neng

    2015-07-01

    Glomerulo-podocytic communication plays an important role in the podocytic injury in IgA nephropathy (IgAN). In this study, we examine the role of podocytic angiotensin II receptor subtype 1 (AT1R) and prorenin receptor (PRR) in podocytic apoptosis in IgAN. Polymeric IgA (pIgA) was isolated from patients with IgAN and healthy controls. Conditioned media were prepared from growth arrested human mesangial cells (HMC) incubated with pIgA from patients with IgAN (IgA-HMC media) or healthy controls (Ctl-HMC media). A human podocyte cell line was used as a model to examine the regulation of the expression of AT1R, PRR, TNF-α and CTGF by IgA-HMC media. Podocytic nephrin expression, annexin V binding and caspase 3 activity were used as the functional readout of podocytic apoptosis. IgA-HMC media had no effect on AngII release by podocytes. IgA-HMC media significantly up-regulated the expression of AT1R and PRR, down-regulated nephrin expression and induced apoptosis in podocytes. Mono-blockade of AT1R, PRR, TNF-α or CTGF partially reduced podocytic apoptosis. IgA-HMC media activated NFκB, notch1 and HEY1 expression by podocytes and dual blockade of AT1R with PRR, or anti-TNF-α with anti-CTGF, effectively rescued the podocytic apoptosis induced by IgA-HMC media. Our data suggests that pIgA-activated HMC up-regulates the expression of AT1R and PRR expression by podocytes and the associated activation of NFκB and notch signalling pathways play an essential role in the podocytic apoptosis induced by glomerulo-podocytic communication in IgAN. Simultaneously targeting the AT1R and PRR could be a potential therapeutic option to reduce the podocytic injury in IgAN.

  19. Up-Regulation of Endothelin Type A Receptor in Human and Rat Radiation Proctitis: Preclinical Therapeutic Approach With Endothelin Receptor Blockade

    SciTech Connect

    Jullien, Nicolash; Blirando, Karl; Milliat, Fabien; Benderitter, Marc; Francois, Agnes

    2009-06-01

    Purpose: Rectum radiation damage and fibrosis are often associated with radiation therapy of pelvic tumors. The endothelin (ET) system has been implicated in several fibrotic diseases but never studied in the context of gastrointestinal radiation damage. This study assessed modifications in ET type 1 (ET-1), ET type A receptor (ET{sub A}), and ET type B receptor (ET{sub B}) localization and/or expression in irradiated human rectal tissue and in a rat model of delayed colorectal injury. We also evaluated the therapeutic potential of long-term ET receptor blockade. Methods and Materials: Routine histological studies of sections of healthy and radiation-injured human rectum tissue were done; the sections were also immunostained for ET{sub A} and ET{sub B} receptors. The rat model involved the delivery of 27 Gy in a single dose to the colons and rectums of the animals. The ET-1/ET{sub A}/ET{sub B} expression and ET{sub A}/ET{sub B} localization were studied at 10 weeks postexposure. The abilities of bosentan and atrasentan to protect against delayed rectal injury were also investigated. Results: The immunolocalization of ET{sub A} and ET{sub B} in healthy human rectums was similar to that in rat rectums. However, strong ET{sub A} immunostaining was seen in the presence of human radiation proctitis, and increased ET{sub A} mRNA levels were seen in the rat following colorectal irradiation. Immunostaining for ET{sub A} was also strongly positive in rats in areas of radiation-induced mucosal ulceration, atypia, and fibroproliferation. However, neither bosentan nor atrasentan prevented radiation damage to the rectum when given long term. The only effect seen for atrasentan was an increased number of sclerotic vessel sections in injured tissues. Conclusions: As the result of the overexpression of ET{sub A}, radiation exposure deregulates the endothelin system through an 'ET{sub A} profile' in the human and rodent rectum. However, therapeutic interventions involving mixed or

  20. Double blockade of angiotensin II (AT1)-receptors and ACE does not improve weight gain and glucose homeostasis better than single-drug treatments in obese rats

    PubMed Central

    Miesel, Anja; Müller-Fielitz, Helge; Jöhren, Olaf; Vogt, Florian M; Raasch, Walter

    2012-01-01

    BACKGROUND AND PURPOSE Combination therapies are becoming increasingly important for the treatment of high blood pressure. Little is known about whether double blockade of angiotensin II (AT1) receptors and angiotensin-converting enzyme (ACE) exert synergistic metabolic effects. EXPERIMENTAL APPROACH Spontaneously hypertensive rats were allowed to choose between palatable chocolate bars and standard chow and were simultaneously treated with the AT1 blocker telmisartan (8 mg·kgbw−1·day−1), the ACE inhibitor ramipril (4 mg·kgbw−1·day−1) or a combination of the two (8 + 4 mg·kgbw−1·day−1) for 12 weeks. KEY RESULTS Although food-dependent energy intake was increased by telmisartan and telmisartan + ramipril compared with ramipril or controls, body weight gain, abundance of fat and plasma leptin levels were decreased. Increased insulin levels in response to an oral glucose tolerance test were comparably attenuated by telmisartan and telmisartan + ramipril, but not by ramipril. During an insulin tolerance test, glucose utilization was equally as effectively improved by telmisartan and telmisartan + ramipril. In response to a stress test, ACTH, corticosterone and glucose increased in controls. These stress reactions were attenuated by telmisartan and telmisartan + ramipril. CONCLUSIONS AND IMPLICATIONS The combination of telmisartan + ramipril was no more efficacious in regulating body weight and glucose homeostasis than telmisartan alone. However, telmisartan was more effective than ramipril in improving metabolic parameters and in reducing body weight. The association between the decrease in stress responses and the diminished glucose levels after stress supports our hypothesis that the ability of telmisartan, as an AT1 receptor blocker, to alleviate stress reactions may contribute to its hypoglycaemic actions. PMID:22014027

  1. Double blockade of angiotensin II (AT(1) )-receptors and ACE does not improve weight gain and glucose homeostasis better than single-drug treatments in obese rats.

    PubMed

    Miesel, Anja; Müller-Fielitz, Helge; Jöhren, Olaf; Vogt, Florian M; Raasch, Walter

    2012-04-01

    Combination therapies are becoming increasingly important for the treatment of high blood pressure. Little is known about whether double blockade of angiotensin II (AT(1) ) receptors and angiotensin-converting enzyme (ACE) exert synergistic metabolic effects. Spontaneously hypertensive rats were allowed to choose between palatable chocolate bars and standard chow and were simultaneously treated with the AT(1) blocker telmisartan (8 mg·kg(bw) (-1) ·day(-1) ), the ACE inhibitor ramipril (4 mg·kg(bw) (-1) ·day(-1) ) or a combination of the two (8 + 4 mg·kg(bw) (-1) ·day(-1) ) for 12 weeks. Although food-dependent energy intake was increased by telmisartan and telmisartan + ramipril compared with ramipril or controls, body weight gain, abundance of fat and plasma leptin levels were decreased. Increased insulin levels in response to an oral glucose tolerance test were comparably attenuated by telmisartan and telmisartan + ramipril, but not by ramipril. During an insulin tolerance test, glucose utilization was equally as effectively improved by telmisartan and telmisartan + ramipril. In response to a stress test, ACTH, corticosterone and glucose increased in controls. These stress reactions were attenuated by telmisartan and telmisartan + ramipril. The combination of telmisartan + ramipril was no more efficacious in regulating body weight and glucose homeostasis than telmisartan alone. However, telmisartan was more effective than ramipril in improving metabolic parameters and in reducing body weight. The association between the decrease in stress responses and the diminished glucose levels after stress supports our hypothesis that the ability of telmisartan, as an AT(1) receptor blocker, to alleviate stress reactions may contribute to its hypoglycaemic actions. © 2011 The Authors. British Journal of Pharmacology © 2011 The British Pharmacological Society.

  2. Systemic Blockade of D2-Like Dopamine Receptors Facilitates Extinction of Conditioned Fear in Mice

    ERIC Educational Resources Information Center

    Ponnusamy, Ravikumar; Nissim, Helen A.; Barad, Mark

    2005-01-01

    Extinction of conditioned fear in animals is the explicit model of behavior therapy for human anxiety disorders, including panic disorder, obsessive-compulsive disorder, and post-traumatic stress disorder. Based on previous data indicating that fear extinction in rats is blocked by quinpirole, an agonist of dopamine D2 receptors, we hypothesized…

  3. Targeting β3-Adrenergic Receptors in the Heart: Selective Agonism and β-Blockade

    PubMed Central

    Cannavo, Alessandro

    2017-01-01

    Abstract: Cardiac diseases, such as heart failure, remain leading causes of morbidity and mortality worldwide, with myocardial infarction as the most common etiology. HF is characterized by β-adrenergic receptor (βAR) dysregulation that is primarily due to the upregulation of G protein–coupled receptor kinases that leads to overdesensitization of β1 and β2ARs, and this clinically manifests as a loss of inotropic reserve. Interestingly, the “minor” βAR isoform, the β3AR, found in the heart, lacks G protein–coupled receptor kinases recognition sites, and is not subject to desensitization, and as a consequence of this, in human failing myocardium, the levels of this receptor remain unchanged or are even increased. In different preclinical studies, it has been shown that β3ARs can activate different signaling pathways that can protect the heart. The clinical relevance of this is also supported by the effects of β-blockers which are well known for their proangiogenic and cardioprotective effects, and data are emerging showing that these are mediated, at least in part, by enhancement of β3AR activity. In this regard, targeting of β3ARs could represent a novel potential strategy to improve cardiac metabolism, function, and remodeling. PMID:28170359

  4. Blockade of calcium-permeable AMPA receptors protects hippocampal neurons against global ischemia-induced death

    PubMed Central

    Noh, Kyung-Min; Yokota, Hidenori; Mashiko, Toshihiro; Castillo, Pablo E.; Zukin, R. Suzanne; Bennett, Michael V. L.

    2005-01-01

    Transient global or forebrain ischemia induced experimentally in animals can cause selective, delayed neuronal death of hippocampal CA1 pyramidal neurons. A striking feature is a delayed rise in intracellular free Zn2+ in CA1 neurons just before the onset of histologically detectable cell death. Here we show that α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA)-type glutamate receptors (AMPARs) at Schaffer collateral to CA1 synapses in postischemic hippocampus exhibit properties of Ca2+/Zn2+-permeable, Glu receptor 2 (GluR2)-lacking AMPARs before the rise in Zn2+ and cell death. At 42 h after ischemia, AMPA excitatory postsynaptic currents exhibited pronounced inward rectification and marked sensitivity to 1-naphthyl acetyl spermine (Naspm), a selective channel blocker of GluR2-lacking AMPARs. In control hippocampus, AMPA excitatory postsynaptic currents were electrically linear and relatively insensitive to Naspm. Naspm injected intrahippocampally at 9-40 h after insult greatly reduced the late rise in intracellular free Zn2+ in postischemic CA1 neurons and afforded partial protection against ischemia-induced cell death. These results implicate GluR2-lacking AMPA receptors in the ischemia-induced rise in free Zn2+ and death of CA1 neurons, although a direct action at the time of the rise in Zn2+ is unproven. This receptor subtype appears to be an important therapeutic target for intervention in ischemia-induced neuronal death in humans. PMID:16093311

  5. Systemic Blockade of D2-Like Dopamine Receptors Facilitates Extinction of Conditioned Fear in Mice

    ERIC Educational Resources Information Center

    Ponnusamy, Ravikumar; Nissim, Helen A.; Barad, Mark

    2005-01-01

    Extinction of conditioned fear in animals is the explicit model of behavior therapy for human anxiety disorders, including panic disorder, obsessive-compulsive disorder, and post-traumatic stress disorder. Based on previous data indicating that fear extinction in rats is blocked by quinpirole, an agonist of dopamine D2 receptors, we hypothesized…

  6. Blockade of 5-HT2 Receptor Selectively Prevents MDMA-Induced Verbal Memory Impairment

    PubMed Central

    van Wel, J H P; Kuypers, K P C; Theunissen, E L; Bosker, W M; Bakker, K; Ramaekers, J G

    2011-01-01

    3,4-Methylenedioxymethamphetamine (MDMA) or ‘ecstasy' has been associated with memory deficits during abstinence and intoxication. The human neuropharmacology of MDMA-induced memory impairment is unknown. This study investigated the role of 5-HT2A and 5-HT1A receptors in MDMA-induced memory impairment. Ketanserin is a 5-HT2A receptor blocker and pindolol a 5-HT1A receptor blocker. It was hypothesized that pretreatment with ketanserin and pindolol would protect against MDMA-induced memory impairment. Subjects (N=17) participated in a double-blind, placebo-controlled, within-subject design involving six experimental conditions consisting of pretreatment (T1) and treatment (T2). T1 preceded T2 by 30 min. T1–T2 combinations were: placebo–placebo, pindolol 20 mg–placebo, ketanserin 50 mg–placebo, placebo–MDMA 75 mg, pindolol 20 mg–MDMA 75 mg, and ketanserin 50 mg–MDMA 75 mg. Memory function was assessed at Tmax of MDMA by means of a word-learning task (WLT), a spatial memory task and a prospective memory task. MDMA significantly impaired performance in all memory tasks. Pretreatment with a 5-HT2A receptor blocker selectively interacted with subsequent MDMA treatment and prevented MDMA-induced impairment in the WLT, but not in the spatial and prospective memory task. Pretreatment with a 5-HT1A blocker did not affect MDMA-induced memory impairment in any of the tasks. Together, the results demonstrate that MDMA-induced impairment of verbal memory as measured in the WLT is mediated by 5-HT2A receptor stimulation. PMID:21562484

  7. Changes in contractile activity of rabbit colon under stress conditions and during post-stress period before and after blockade of muscarinic and nicotinic cholinergic receptors.

    PubMed

    Ovsiannikov, V I; Berezina, T P

    2013-06-01

    Psychogenic stress in rabbits induced by fixation of the animal to a frame was accompanied by an increase in contractile activity of the initial portion of the distal colon, which was abolished by blockade of muscarinic and nicotinic cholinergic receptors. Increased contractile activity of the colon was due to centrogenic stimulation of preganglionic neurons of the parasympathetic nervous system followed by the involvement of the effector cholinergic neurons of the enteric nervous system into excitation.

  8. Intra-Articular Blockade of P2X7 Receptor Reduces the Articular Hyperalgesia and Inflammation in the Knee Joint Synovitis Especially in Female Rats.

    PubMed

    Teixeira, Juliana Maia; Dias, Elayne Vieira; Parada, Carlos Amílcar; Tambeli, Cláudia Herrera

    2017-02-01

    Synovitis is a key factor in joint disease pathophysiology, which affects a greater proportion of women than men. P2X7 receptor activation contributes to arthritis, but whether it plays a role in articular inflammatory pain in a sex-dependent manner is unknown. We investigated whether the P2X7 receptor blockade in the knee joint of male and female rats reduces the articular hyperalgesia and inflammation induced by a carrageenan knee joint synovitis model. Articular hyperalgesia was quantified using the rat knee joint incapacitation test and the knee joint inflammation, characterized by the concentration of cytokines tumor necrosis factor-α, interleukin-1β, interleukin-6, and cytokine-induced neutrophil chemoattractant-1, and by neutrophil migration, was quantified using enzyme-linked immunosorbent assay and by myeloperoxidase enzyme activity measurement, respectively. P2X7 receptor blockade by the articular coadministration of selective P2X7 receptor antagonist A740003 with carrageenan significantly reduced articular hyperalgesia, pro-inflammatory cytokine concentrations, and myeloperoxidase activity induced by carrageenan injection into the knee joint of male and estrus female rats. However, a lower dose of P2X7 receptor antagonist was sufficient to significantly induce the antihyperalgesic and anti-inflammatory effects in estrus female but not in male rats. These results suggest that P2X7 receptor activation by endogenous adenosine 5'-triphosphate is essential to articular hyperalgesia and inflammation development in the knee joint of male and female rats. However, female rats are more responsive than male rats to the antihyperalgesic and anti-inflammatory effects induced by P2X7 receptor blockade.

  9. Blockade of patch-based μ opioid receptors in the striatum attenuates methamphetamine-induced conditioned place preference and reduces activation of the patch compartment.

    PubMed

    Horner, Kristen A; Logan, Mary Caroline; Fisher, Trevor J; Logue, Jordan B

    2017-02-05

    The behavioral effects of methamphetamine (METH) are mediated by the striatum, which is divided into the patch compartment, which mediates limbic and reward functions, and the matrix compartment, which mediates sensorimotor tasks. METH treatment results in repetitive behavior that is related to enhanced relative activation of the patch versus the matrix compartment. The patch, but not the matrix compartment contains a high density of μ opioid receptors, and localized blockade of patch-based μ opioid receptors attenuates METH-induced patch-enhanced activity and repetitive behaviors. Numerous studies have examined patch-enhanced activity and the contribution of patch-associated μ opioid receptors to METH-induced repetitive behavior, but it is not known whether patch-enhanced activity occurs during METH-mediated reward, nor is it known if patch-based μ opioid receptors contribute to METH reward. The goals of this study were to determine if blockade of patch-based μ opioid receptors alters METH-induced conditioned place preference (CPP), as well activation of the patch and matrix compartments following METH-mediated CPP. A biased conditioning paradigm was used to assess CPP, and conditioning occurred over an 8-d period. Animals were bilaterally infused in the striatum with the μ-specific antagonist CTAP or vehicle prior to conditioning. Animals were tested for preference 24h after the last day of conditioning, sacrificed and the brains processed for immunohistochemistry. Blockade of patch-based μ opioid receptors reduced METH-induced CPP, and reduced patch-enhanced c-Fos expression in the striatum following METH-mediated CPP. These data indicate that patch-enhanced activity is associated with METH-mediated reward and patch-based μ opioid receptors contribute to this phenomenon.

  10. Blockade of transient receptor potential cation channel subfamily V member 1 promotes regeneration after sciatic nerve injury

    PubMed Central

    Ren, Fei; Zhang, Hong; Qi, Chao; Gao, Mei-ling; Wang, Hong; Li, Xia-qing

    2015-01-01

    The transient receptor potential cation channel subfamily V member 1 (TRPV1) provides the sensation of pain (nociception). However, it remains unknown whether TRPV1 is activated after peripheral nerve injury, or whether activation of TRPV1 affects neural regeneration. In the present study, we established rat models of unilateral sciatic nerve crush injury, with or without pretreatment with AMG517 (300 mg/kg), a TRPV1 antagonist, injected subcutaneously into the ipsilateral paw 60 minutes before injury. At 1 and 2 weeks after injury, we performed immunofluorescence staining of the sciatic nerve at the center of injury, at 0.3 cm proximal and distal to the injury site, and in the dorsal root ganglia. Our results showed that Wallerian degeneration occurred distal to the injury site, and neurite outgrowth and Schwann cell regeneration occurred proximal to the injury. The number of regenerating myelinated and unmyelinated nerve clusters was greater in the AMG517-pretreated rats than in the vehicle-treated group, most notably 2 weeks after injury. TRPV1 expression in the injured sciatic nerve and ipsilateral dorsal root ganglia was markedly greater than on the contralateral side. Pretreatment with AMG517 blocked this effect. These data indicate that TRPV1 is activated or overexpressed after sciatic nerve crush injury, and that blockade of TRPV1 may accelerate regeneration of the injured sciatic nerve. PMID:26487864

  11. Blockade of NMDA receptors in the amygdala prevents latent inhibition of fear-conditioning.

    PubMed

    Schauz, C; Koch, M

    2000-01-01

    The association between a conditioned stimulus (CS) and an unconditioned stimulus (US) in fear-conditioning depends on N-methyl-D-aspartate (NMDA) receptors in the basolateral amygdala complex (BLA). Latent inhibition (LI) is the retardation in learning due to nonreinforced presentation of the prospective CS before conditioning. Disruption of LI in rats is an animal model of schizophrenia, reflecting the deficits of schizophrenic patients in neglecting irrelevant information. We investigated whether the BLA is involved in LI of fear-potentiated startle. Infusions of the NMDA receptor antagonist D,L-2-amino-5-phosphonopentanoic acid (AP-5; 12.5 nmoles) into the BLA before preexposure of rats to the neutral stimulus prevent LI of fear-conditioning. We also demonstrated by the same method that a complex of thalamic nuclei, comprising the medial part of the medial geniculate nucleus, the posterior intralaminar nucleus, and the suprageniculate nucleus, is involved in fear-conditioning, but not in LI. This suggests that the presentation of an innocuous stimulus during preexposure leads to an NMDA receptor-dependent change of neurotransmission in the BLA, but not in the thalamus. Our data show that the BLA but not the thalamus regulates in LI of fear-potentiated startle. Furthermore, it supports the hypothesis that the inability of schizophrenic patients to ignore irrelevant stimuli may be caused by hypofunction of the glutamatergic transmission in the brain and suggests an involvement of the amygdala in the neuropathology of schizophrenia.

  12. Blockade of NMDA Receptors in the Amygdala Prevents Latent Inhibition of Fear-Conditioning

    PubMed Central

    Schauz, Cornelia; Koch, Michael

    2000-01-01

    The association between a conditioned stimulus (CS) and an unconditioned stimulus (US) in fear-conditioning depends on N-methyl-d-aspartate (NMDA) receptors in the basolateral amygdala complex (BLA). Latent inhibition (LI) is the retardation in learning due to nonreinforced presentation of the prospective CS before conditioning. Disruption of LI in rats is an animal model of schizophrenia, reflecting the deficits of schizophrenic patients in neglecting irrelevant information. We investigated whether the BLA is involved in LI of fear-potentiated startle. Infusions of the NMDA receptor antagonist d,l-2-amino-5-phosphonopentanoic acid (AP-5; 12.5 nmoles) into the BLA before preexposure of rats to the neutral stimulus prevent LI of fear-conditioning. We also demonstrated by the same method that a complex of thalamic nuclei, comprising the medial part of the medial geniculate nucleus, the posterior intralaminar nucleus, and the suprageniculate nucleus, is involved in fear-conditioning, but not in LI. This suggests that the presentation of an innocuous stimulus during preexposure leads to an NMDA receptor-dependent change of neurotransmission in the BLA, but not in the thalamus. Our data show that the BLA but not the thalamus regulates in LI of fear-potentiated startle. Furthermore, it supports the hypothesis that the inability of schizophrenic patients to ignore irrelevant stimuli may be caused by hypofunction of the glutamatergic transmission in the brain and suggests an involvement of the amygdala in the neuropathology of schizophrenia. PMID:11112798

  13. Blockade of CCR7 leads to decreased dendritic cell migration to draining lymph nodes and promotes graft survival in low-risk corneal transplantation.

    PubMed

    Hos, D; Dörrie, J; Schaft, N; Bock, F; Notara, M; Kruse, F E; Krautwald, S; Cursiefen, C; Bachmann, B O

    2016-05-01

    The chemokine receptor CCR7 is essential for migration of mature dendritic cells (DCs) to the regional lymph nodes, and it has been shown that blocking of CCR7 improves graft survival after high-risk corneal transplantation in vascularized recipient corneas. However, it is so far unknown whether blocking of CCR7 reduces migration of DCs from the avascular cornea to the draining lymph nodes and whether this leads to improved graft survival also in the low-risk setting of corneal transplantation, which accounts for the majority of perforating transplantations performed. Therefore, in this study, pellets containing Freund's adjuvant and bovine serum albumin (BSA) conjugated to Alexa488 fluorescent dye were implanted into the corneal stroma of BALB/c mice to analyze antigen uptake by corneal DCs and their migration to the regional lymph nodes. After pellet implantation, mice were either treated by local administration of a CCR7 blocking fusion protein that consisted of CCL19 fused to the Fc part of human IgG1 or a control-IgG. In vivo fluorescence microscopy showed uptake of Alexa488-conjugated BSA by corneal DCs within 8 h. Furthermore, analysis of single cell suspensions of draining lymph nodes prepared after 48 h revealed that 2.1 ± 0.3% of CD11c(+) cells were also Alexa488(+). Importantly, DC migration was significantly reduced after topical administration of CCL19-IgG (1.2 ± 0.2%; p < 0.05). To test the effect of CCR7 blockade on graft rejection after allogeneic low-risk keratoplasty, corneal transplantations were performed using C57BL/6-mice as donors and BALB/c-mice as recipients. Treatment mice received two intraperitoneal loading doses of CCL19-IgG prior to transplantation, followed by local treatment with CCL19-IgG containing eye drops for the first two weeks after transplantation. Control mice received same amounts of control-IgG. Kaplan-Meier survival analysis showed that in the CCL19-IgG treated group, 76% of the grafts survived through the end

  14. Blockade of mGluR1 receptor results in analgesia and disruption of motor and cognitive performances: effects of A-841720, a novel non-competitive mGluR1 receptor antagonist

    PubMed Central

    El-Kouhen, O; Lehto, S G; Pan, J B; Chang, R; Baker, S J; Zhong, C; Hollingsworth, P R; Mikusa, J P; Cronin, E A; Chu, K L; McGaraughty, S P; Uchic, M E; Miller, L N; Rodell, N M; Patel, M; Bhatia, P; Mezler, M; Kolasa, T; Zheng, G Z; Fox, G B; Stewart, A O; Decker, M W; Moreland, R B; Brioni, J D; Honore, P

    2006-01-01

    Background and purpose: To further assess the clinical potential of the blockade of metabotropic glutamate receptors (mGluR1) for the treatment of pain. Experimental approach: We characterized the effects of A-841720, a novel, potent and non-competitive mGluR1 antagonist in models of pain and of motor and cognitive function. Key results: At recombinant human and native rat mGluR1 receptors, A-841720 inhibited agonist-induced calcium mobilization, with IC50 values of 10.7±3.9 and 1.0±0.2 nM, respectively, while showing selectivity over other mGluR receptors, in addition to other neurotransmitter receptors, ion channels, and transporters. Intraperitoneal injection of A-841720 potently reduced complete Freund's adjuvant-induced inflammatory pain (ED50=23 μmol kg−1) and monoiodoacetate-induced joint pain (ED50=43 μmol kg−1). A-841720 also decreased mechanical allodynia observed in both the sciatic nerve chronic constriction injury and L5-L6 spinal nerve ligation (SNL) models of neuropathic pain (ED50=28 and 27 μmol kg−1, respectively). Electrophysiological studies demonstrated that systemic administration of A-841720 in SNL animals significantly reduced evoked firing in spinal wide dynamic range neurons. Significant motor side effects were observed at analgesic doses and A-841720 also impaired cognitive function in the Y-maze and the Water Maze tests. Conclusions and implications. The analgesic effects of a selective mGluR1 receptor antagonist are associated with motor and cognitive side effects. The lack of separation between efficacy and side effects in pre-clinical models indicates that mGluR1 antagonism may not provide an adequate therapeutic window for the development of such antagonists as novel analgesic agents in humans. PMID:17016515

  15. Decreasing nicotinic receptor activity and the spatial learning impairment caused by the NMDA glutamate antagonist dizocilpine in rats

    PubMed Central

    Burke, Dennis A.; Heshmati, Pooneh; Kholdebarin, Ehsan; Levin, Edward D.

    2014-01-01

    Nicotinic systems have been shown by a variety of studies to be involved in cognitive function. Nicotinic receptors have an inherent property to become desensitized after activation. The relative role of nicotinic receptor activation vs. net receptor inactivation by desensitization in the cognitive effects of nicotinic drugs remains to be fully understood. In these studies, we tested the effects of the α7 nicotinic receptor antagonist methyllycaconitine (MLA), the α4β2 nicotinic receptor antagonist dihydro-β-erythroidine (DHβE), the nonspecific nicotinic channel blocker mecamylamine and the α4β2 nicotinic receptor desensitizing agent sazetidine-A on learning in a repeated acquisition test. Adult female Sprague-Dawley rats were trained on a repeated acquisition learning procedure in an 8-arm radial maze. MLA (1–4 mg/kg), DHβE (1–4 mg/kg), mecamylamine (0.125–0.5 mg/kg) or sazetidine-A (1 and 3 mg/kg) were administered in four different studies either alone or together with the NMDA glutamate antagonist dizocilpine (0.05 and 0.10 mg/kg). MLA significantly counteracted the learning impairment caused by dizocilpine. The overall choice accuracy impairment caused by dizocilpine was significantly attenuated by co-administration of DHβE. Low doses of the non-specific nicotinic antagonist mecamylamine also reduced dizocilpine-induced repeated acquisition impairment. Sazetidine-A reversed the accuracy impairment caused by dizocilpine. These studies provide evidence that a net decrease in nicotinic receptor activity can improve learning by attenuating learning impairment induced by NMDA glutamate blockade. This adds to evidence in cognitive tests that nicotinic antagonists can improve cognitive function. Further research characterizing the efficacy and mechanisms underlying nicotinic antagonist and desensitization induced cognitive improvement is warranted. PMID:25064338

  16. Selective blockade of drug-induced place preference conditioning by ACPC, a functional NDMA-receptor antagonist.

    PubMed

    Papp, Marius; Gruca, Piotr; Willner, Paul

    2002-11-01

    ACPC (1-aminocyclopropanecarboxylic acid) is a partial agonist at the strychnine-insensitive glycine receptor site on the NMDA receptor complex, and a functional NMDA antagonist. A series of experiments was conducted to assess the effects of ACPC in a biased place conditioning paradigm. As previously reported, ACPC itself did not support either appetitive or aversive place conditioning. However, co-administration of ACPC (200 mg/kg) blocked the acquisition of place preferences conditioned using a variety of psychoactive drugs (amphetamine, cocaine, nomifensine, diazepam, morphine, nicotine). No tolerance was seen to this effect following two weeks of chronic ACPC administration. Overall, ACPC did not affect the expression of place conditioning when administered immediately before the post-conditioning test. However, these effects appeared somewhat variable between drugs, and further analysis showed that ACPC did block the expression of preferences conditioned with some drugs (diazepam, morphine, nicotine), but not others (amphetamine, cocaine, nomifensine). The effects of ACPC could not be accounted for by state dependence, as ACPC blocked morphine and cocaine place preferences when administered during both the acquisition and the expression phase of conditioning. In contrast to the blockade by ACPC of drug-induced place preferences, ACPC had no effect on the acquisition of place preferences conditioned using a variety of natural non-drug reinforcers (food, sucrose, social interaction, novelty). ACPC also had no effect on the acquisition of drug-induced place aversions (naloxone, picrotoxin). Thus, ACPC selectively blocked appetitive conditioning by drug reinforcers, without affecting either appetitive conditioning by natural reinforcers or drug-induced aversions. As place preference conditioning has been demonstrated to have high predictive validity for detecting compounds with an abuse potential in humans, this selective action suggests that ACPC might have some

  17. Renal denervation mitigates cardiac remodeling and renal damage in Dahl rats: a comparison with β-receptor blockade.

    PubMed

    Watanabe, Heitaro; Iwanaga, Yoshitaka; Miyaji, Yuki; Yamamoto, Hiromi; Miyazaki, Shunichi

    2016-04-01

    Chronic activation of the sympathetic nervous system (SNS) contributes to cardiac remodeling and the transition to heart failure (HF). Renal sympathetic denervation (RDN) may ameliorate this damage by improving renal function and sympathetic cardioregulation in hypertensive HF patients with renal injury. The efficacy may be comparable to that of chronic β-blocker treatment. Dahl salt-sensitive hypertensive rats were subjected to RDN in the hypertrophic stage. Another group of Dahl rats were subjected to sham operations and treated chronically with vehicle (CONT) or β-blocker bisoprolol (BISO). Neither RDN nor BISO altered the blood pressure; however, BISO significantly reduced the heart rate (HR). Both RDN and BISO significantly prolonged survival (22.2 and 22.4 weeks, respectively) compared with CONT (18.3 weeks). Echocardiography revealed reduced left ventricular (LV) hypertrophy and improved LV function, and histological analysis demonstrated the amelioration of LV myocyte hypertrophy and fibrosis in the RDN and BISO rats at the HF stage. Tyrosine hydroxylase and β1-adrenergic receptor (ADR) expression levels in the LV myocardium significantly increased only in the RDN rats, whereas the α1b-, α1d- and α2c-ADR expression levels increased only in the BISO rats. In both groups, renal damage and dysfunction were also reduced, and this reduction was accompanied by the suppression of endothelin-1, renin and angiotensin-converting enzyme mRNAs. RDN ameliorated the progression of both myocardial and renal damage in the hypertensive rats independent of blood pressure changes. The overall effects were similar to those of β-receptor blockade with favorable effects on HR and α-ADR expression. These findings may be associated with the restoration of the myocardial SNS and renal protection.

  18. Cardiovascular reactivity after blockade of angiotensin AT1 receptors in the experimental model of tilting test in conscious rats

    PubMed Central

    Bedette, D; Santos, R A S; Fontes, M A P

    2008-01-01

    Background and purpose: Studies have shown that the angiotensin II AT1 receptor antagonist, losartan, accentuates the hypotensive response in the orthostatic stress test (tilt) performed in anaesthetized rats. The same effect was not reported with other AT1 antagonists. The aim of this study was to re-evaluate the effects of AT1 receptor blockade on the cardiovascular response to tilt in a model developed for conscious rats. Experimental approach: Rats (n=5–7 per group) were instrumented for infusion of drugs and recording of cardiovascular parameters and, after recovery, placed in a plastic tube positioned over the tilt board. The tilt test was conducted by raising the head side of the tilt board from horizontal position to 75° head up position for 15 min. Key results: Compared with control group (NaCl 0.9%, 1 ml kg−1), oral treatment with 1 mg kg−1 per day of losartan or telmisartan did not alter the blood pressure response during tilt. With the 10 mg kg−1 dose, both antagonists altered the blood pressure response during tilt (mean maximum changes −11±3 mm Hg; P<0.01). A post-tilt hypotension was observed with both doses in losartan and telmisartan groups (−13±1 and −9±2 mm Hg, respectively; P<0.01). Conclusions and implications: The present results indicate that the effect of losartan on the cardiovascular reactivity to tilt shares a similar profile to that of other AT1 antagonists. Evidence discussed addresses the importance of using a conscious model for testing the influence of antihypertensive drugs on the cardiovascular reactivity to orthostatic challenges. PMID:18193073

  19. Protection by imidazol(ine) drugs and agmatine of glutamate-induced neurotoxicity in cultured cerebellar granule cells through blockade of NMDA receptor

    PubMed Central

    Olmos, Gabriel; DeGregorio-Rocasolano, Nuria; Regalado, M Paz; Gasull, Teresa; Boronat, M Assumpció; Trullas, Ramón; Villarroel, Alvaro; Lerma, Juan; García-Sevilla, Jesús A

    1999-01-01

    This study was designed to assess the potential neuroprotective effect of several imidazol(ine) drugs and agmatine on glutamate-induced necrosis and on apoptosis induced by low extracellular K+ in cultured cerebellar granule cells.Exposure (30 min) of energy deprived cells to L-glutamate (1–100 μM) caused a concentration-dependent neurotoxicity, as determined 24 h later by a decrease in the ability of the cells to metabolize 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazoliumbromide (MTT) into a reduced formazan product. L-glutamate-induced neurotoxicity (EC50=5 μM) was blocked by the specific NMDA receptor antagonist MK-801 (dizocilpine).Imidazol(ine) drugs and agmatine fully prevented neurotoxicity induced by 20 μM (EC100) L-glutamate with the rank order (EC50 in μM): antazoline (13)>cirazoline (44)>LSL 61122 [2-styryl-2-imidazoline] (54)>LSL 60101 [2-(2-benzofuranyl) imidazole] (75)>idazoxan (90)>LSL 60129 [2-(1,4-benzodioxan-6-yl)-4,5-dihydroimidazole] (101)>RX821002 (2-methoxy idazoxan) (106)>agmatine (196). No neuroprotective effect of these drugs was observed in a model of apoptotic neuronal cell death (reduction of extracellular K+) which does not involve stimulation of NMDA receptors.Imidazol(ine) drugs and agmatine fully inhibited [3H]-(+)-MK-801 binding to the phencyclidine site of NMDA receptors in rat brain. The profile of drug potency protecting against L-glutamate neurotoxicity correlated well (r=0.90) with the potency of the same compounds competing against [3H]-(+)-MK-801 binding.In HEK-293 cells transfected to express the NR1-1a and NR2C subunits of the NMDA receptor, antazoline and agmatine produced a voltage- and concentration-dependent block of glutamate-induced currents. Analysis of the voltage dependence of the block was consistent with the presence of a binding site for antazoline located within the NMDA channel pore with an IC50 of 10–12 μM at 0 mV.It is concluded that imidazol(ine) drugs and agmatine are

  20. CD28 family of receptors on T cells in chronic HBV infection: Expression characteristics, clinical significance and correlations with PD-1 blockade

    PubMed Central

    Tang, Zong-Sheng; Hao, You-Hua; Zhang, E-Juan; Xu, Chun-Li; Zhou, Yun; Zheng, Xin; Yang, Dong-Liang

    2016-01-01

    The aim of the present study was to investigate the overall clinical expression characteristics of the cluster of differentiation (CD)28 family receptors [CD28, inducible T-cell co-stimulator, programmed cell death protein 1 (PD-1), cytotoxic T-lymphocyte-associated protein 4 and B- and T-lymphocyte attenuator] on T cells in patients with chronic hepatitis B (CHB), analyze the correlations among these receptors and the clinical parameters, and to investigate the effects of PD-1 blockade on the receptor expression profiles, T-cell function and other biological effects. The expression characteristics of the CD28 family of receptors, the effects of PD-1 blockade on the receptor expression profiles and the levels of interferon (IFN)-γ were investigated in the T cells of patients with CHB. In addition, the transcription factor, T-box 21 (T-bet) and GATA binding protein 3 (GATA-3) mRNA expression levels were investigated in the peripheral blood mononuclear cells (PBMCs) of patients with CHB. The expression levels of the CD28 family receptors in the T cells of patients with CHB demonstrated distinct characteristics, for example levels of PD-1 and CTLA-4 on CD4 T cells and ICOS, PD-1, and BTLA on CD8 T cells were increased in cells from patients with CHB compared with those from the healthy individuals. A significant positive correlation was demonstrated among the serum HBV DNA titers and the levels of PD-1 on CD8+ T cells with the highest expression of PD-1 corresponding to viral levels >106 IU/ml. A significant positive correlation was observed between the serum HBV DNA titers and the expression levels of BTLA on CD8+ T cells with the highest expression of BTLA corresponding to viral levels >106 IU/ml. PD-1 blockade altered the expression profiles of CD28 family receptors in the T cells of patients with CHB, partly enhanced T cell function and increased the ratio of T-bet/GATA-3 mRNA in PBMCs. Thus, CD28 family receptors are potential clinical indicators for the rapid

  1. Acute AT1-receptor blockade reverses the hemodynamic and baroreflex impairment in adult sheep exposed to antenatal betamethasone

    PubMed Central

    Rose, James C.; Figueroa, Jorge P.; Chappell, Mark C.; Diz, Debra I.; Averill, David B.

    2010-01-01

    To accelerate lung development and protect neonates from other early developmental problems, synthetic steroids are administered maternally in the third trimester, exposing fetuses that are candidates for premature delivery to them. However, steroid exposure at this point of gestation may lead to elevated blood pressure [mean arterial pressure (MAP)] during adolescence. We hypothesize that fetal exposure to steroids activates the renin-angiotensin system, inducing an elevation in blood pressure and attenuation of baroreflex sensitivity (BRS) that is angiotensin II dependent in early adulthood. To test this hypothesis, fetal sheep were exposed to betamethasone (Beta) or vehicle (control) administered to ewes at day 80 of gestation and delivered at full term. At 1.8 yr of age, male offspring were instrumented for conscious recording of MAP, heart rate, and measurement of BRS [as low-frequency-α, high-frequency-α, sequence (seq) UP, seq DOWN, and seq TOTAL]. Beta-exposed sheep (n = 6) had higher MAP than control sheep (n = 5) (93 ± 2 vs. 84 ± 2 mmHg, P < 0.01). Acute blockade of angiotensin type 1 receptors with candesartan (0.3 mg/kg iv) normalized MAP in Beta-exposed sheep (85 ± 4 mmHg), with no effect in control sheep (82 ± 3 mmHg). Before angiotensin type 1 blockade, BRS maximum gain was significantly lower in Beta-exposed vs. control sheep (11 ± 3 vs. 26 ± 3 ms/mmHg, P < 0.0.01). However, 45 min after candesartan injection, BRS was increased in Beta-exposed (21 ± 5 ms/mmHg) and control (35 ± 4 ms/mmHg) sheep. Heart rate variability (HRV) and blood pressure variability (BPV) revealed lower HRV (SD of beat-to-beat interval and root mean square of successive beat-to-beat differences in R-R interval duration) and higher BPV (SD of MAP, systolic arterial pressure in low-frequency range) in Beta-exposed sheep. Candesartan partially restored HRV in Beta-exposed sheep and fully corrected BPV. Thus, in utero exposure to synthetic glucocorticoids causes long

  2. Treatment of established left ventricular hypertrophy with fibroblast growth factor receptor blockade in an animal model of CKD.

    PubMed

    Di Marco, Giovana Seno; Reuter, Stefan; Kentrup, Dominik; Grabner, Alexander; Amaral, Ansel Philip; Fobker, Manfred; Stypmann, Jörg; Pavenstädt, Hermann; Wolf, Myles; Faul, Christian; Brand, Marcus

    2014-11-01

    Activation of fibroblast growth factor receptor (FGFR)-dependent signalling by FGF23 may contribute to the complex pathogenesis of left ventricular hypertrophy (LVH) in chronic kidney disease (CKD). Pan FGFR blockade by PD173074 prevented development of LVH in the 5/6 nephrectomy rat model of CKD, but its ability to treat and reverse established LVH is unknown. CKD was induced in rats by 5/6 nephrectomy. Two weeks later, rats began treatment with vehicle (0.9% NaCl) or PD173074, 1 mg/kg once-daily for 3 weeks. Renal function was determined by urine and blood analyses. Left ventricular (LV) structure and function were determined by echocardiography, histopathology, staining for myocardial fibrosis (Sirius-Red) and investigating cardiac gene expression profiles by real-time PCR. Two weeks after inducing CKD by 5/6 nephrectomy, rats manifested higher (mean ± SEM) systolic blood pressure (208 ± 4 versus 139 ± 3 mmHg; P < 0.01), serum FGF23 levels (1023 ± 225 versus 199 ± 9 pg/mL; P < 0.01) and LV mass (292 ± 9 versus 220 ± 3 mg; P < 0.01) when compared with sham-operated animals. Thereafter, 3 weeks of treatment with PD173074 compared with vehicle did not significantly change blood pressure, kidney function or metabolic parameters, but significantly reduced LV mass (230 ± 14 versus 341 ± 33 mg; P < 0.01), myocardial fibrosis (2.5 ± 0.7 versus 5.4 ± 0.95% staining/field; P < 0.01) and cardiac expression of genes associated with pathological LVH, while significantly increasing ejection fraction (18 versus 2.5% post-treatment increase; P < 0.05). FGFR blockade improved cardiac structure and function in 5/6 nephrectomy rats with previously established LVH. These data support FGFR activation as a potentially modifiable, blood pressure-independent molecular mechanism of LVH in CKD. © The Author 2014. Published by Oxford University Press on behalf of ERA-EDTA. All rights reserved.

  3. Treatment of established left ventricular hypertrophy with fibroblast growth factor receptor blockade in an animal model of CKD

    PubMed Central

    Di Marco, Giovana Seno; Reuter, Stefan; Kentrup, Dominik; Grabner, Alexander; Amaral, Ansel Philip; Fobker, Manfred; Stypmann, Jörg; Pavenstädt, Hermann; Wolf, Myles; Faul, Christian; Brand, Marcus

    2014-01-01

    Background Activation of fibroblast growth factor receptor (FGFR)-dependent signalling by FGF23 may contribute to the complex pathogenesis of left ventricular hypertrophy (LVH) in chronic kidney disease (CKD). Pan FGFR blockade by PD173074 prevented development of LVH in the 5/6 nephrectomy rat model of CKD, but its ability to treat and reverse established LVH is unknown. Methods CKD was induced in rats by 5/6 nephrectomy. Two weeks later, rats began treatment with vehicle (0.9% NaCl) or PD173074, 1 mg/kg once-daily for 3 weeks. Renal function was determined by urine and blood analyses. Left ventricular (LV) structure and function were determined by echocardiography, histopathology, staining for myocardial fibrosis (Sirius-Red) and investigating cardiac gene expression profiles by real-time PCR. Results Two weeks after inducing CKD by 5/6 nephrectomy, rats manifested higher (mean ± SEM) systolic blood pressure (208 ± 4 versus 139 ± 3 mmHg; P < 0.01), serum FGF23 levels (1023 ± 225 versus 199 ± 9 pg/mL; P < 0.01) and LV mass (292 ± 9 versus 220 ± 3 mg; P < 0.01) when compared with sham-operated animals. Thereafter, 3 weeks of treatment with PD173074 compared with vehicle did not significantly change blood pressure, kidney function or metabolic parameters, but significantly reduced LV mass (230 ± 14 versus 341 ± 33 mg; P < 0.01), myocardial fibrosis (2.5 ± 0.7 versus 5.4 ± 0.95% staining/field; P < 0.01) and cardiac expression of genes associated with pathological LVH, while significantly increasing ejection fraction (18 versus 2.5% post-treatment increase; P < 0.05). Conclusions FGFR blockade improved cardiac structure and function in 5/6 nephrectomy rats with previously established LVH. These data support FGFR activation as a potentially modifiable, blood pressure-independent molecular mechanism of LVH in CKD. PMID:24875663

  4. Aortic Remodeling Following Transverse Aortic Constriction in Mice is Attenuated with AT1 Receptor Blockade

    PubMed Central

    Kuang, Shao-Qing; Geng, Liang; Prakash, Siddharth K.; Cao, Jiu-Mei; Guo, Steven; Villamizar, Carlos; Kwartler, Callie S.; Ju, Xiaoxi; Brasier, Allan R.; Milewicz, Dianna M.

    2016-01-01

    Objective Although hypertension is the most common risk factor for thoracic aortic diseases, it is not understood how increased pressures on the ascending aorta lead to aortic aneurysms. We investigated the role of Ang II type 1 (AT1) receptor activation in ascending aortic remodeling in response to increased biomechanical forces using a transverse aortic constriction (TAC) mouse model. Approach and Results Two weeks after TAC, the increased biomechanical pressures led to ascending aortic dilatation, aortic wall thickening and medial hypertrophy. Significant adventitial hyperplasia and inflammatory responses in TAC ascending aortas were accompanied by increased adventitial collagen, elevated inflammatory and proliferative markers, and increased cell density due to accumulation of myofibroblasts and macrophages. Treatment with losartan significantly blocked TAC induced vascular inflammation and macrophage accumulation. However, losartan only partially prevented TAC induced adventitial hyperplasia, collagen accumulation and ascending aortic dilatation. Increased Tgfb2 expression and phosphorylated-Smad2 staining in the medial layer of TAC ascending aortas was effectively blocked with losartan. In contrast, the increased Tgfb1 expression and adventitial phospho-Smad2 staining were only partially attenuated by losartan. In addition, losartan significantly blocked Erk activation and ROS production in the TAC ascending aorta. Conclusions Inhibition of the AT1 receptor using losartan significantly attenuated the vascular remodeling associated with TAC but did not completely block the increased TGF- β1 expression, adventitial Smad2 signaling and collagen accumulation. These results help to delineate the aortic TGF-β signaling that is dependent and independent of the AT1 receptor after TAC. PMID:23868934

  5. Intra-accumbal CB1 receptor blockade reduced extinction and reinstatement of morphine.

    PubMed

    Khaleghzadeh-Ahangar, Hossein; Haghparast, Abbas

    2015-10-01

    The limbic dopaminergic reward system is the main target of morphine-like drugs which begins from the ventral tegmental area (VTA) and sends its dopaminergic projections to the nucleus accumbens (NAc), amygdala, hippocampus and prefrontal cortex. Cannabinoid receptors exist in afferent neurons from these areas to the NAc and can modulate glutamate synaptic transmission in the NAc. Cannabinoids can interact with the opiate system in reward-related behaviors; nevertheless these systems' interaction in extinction duration and reinstatement has not been shown. In the present study, the effects of bilateral intra-accumbal administration of AM251, a CB1 receptor antagonist, on the duration of the extinction phase and reinstatement to morphine were investigated by conditioned place preference (CPP) paradigm. Forty eight adult male albino Wistar rats were used. Bilateral intra-accumbal administration of AM251 (15, 45 and 90μM/0.5μl DMSO per side) was performed. Subcutaneous administration of morphine (5mg/kg) in three consecutive days was used to induce CPP. The results showed that administration of the maximal dose of AM251 during the extinction period significantly reduces duration of extinction and reinstatement to morphine. Administration of the middle dose during the extinction period significantly attenuated reinstatement to morphine. A single microinjection of the middle dose just before the reinstatement phase significantly attenuated reinstatement to morphine only, while bilateral intra-accumbal administration of neither the lowest dose nor the vehicle (DMSO) had any effects. These results for the first time indicated that CB1 receptors within the NAc are involved in the maintenance of morphine rewarding properties, and morphine seeking behaviors in extinguished morphine-induced CPP rats.

  6. Hormonal responses to opioid receptor blockade: during rest and exercise in cold and hot environments.

    PubMed

    Armstrong, David W; Hatfield, Bradley D

    2006-05-01

    Opioid receptors appear to modulate a variety of physiological and metabolic homeostatic responses to stressors such as exercise and thermally extreme environments. To more accurately determine the role of the naloxone (NAL) sensitive opioid receptor system during rest and exercise, subjects were subjected to concomitant environmental thermal stress. Fifteen untrained men rested or performed low intensity (60% VO2peak) or high intensity (80% VO2peak) exercise on a cycle ergometer for 60 min in an environmental chamber during cold (0 degrees C) hot (35 degrees C) air exposure while receiving an infusion of normal saline (SAL) or NAL (0.1 mg kg(-1)). Plasma adrenocorticotropin hormone (ACTH), immunoreactive beta-endorphin (IBE), cortisol and growth hormone were measured at baseline and every 15 min while in the chamber. Time to exhaustion was significantly reduced during high intensity exercise in the heat (P<0.0001). NAL significantly (P=0.0004) reduced the time to exhaustion (38.3+/-2.1 min) during high intensity exercise in the heat compared to SAL (49.4+/-2.1 min). ACTH and IBE increased during hot conditions and cold attenuated this response. Plasma concentrations of IBE, ACTH, and growth hormone increased significantly with NAL during high intensity exercise in the heat compared to SAL. Cold attenuated the response of ACTH, IBE and cortisol to NAL. NAL administration exaggerates plasma hormone concentration during high intensity exercise in the heat, but not cold. These results support a regulatory effect of the opioid receptor system on physiological responses during exercise in thermally stressful environments. Future research should be directed to more clearly defining the effect of environmental temperature on the mechanism of hypothalamic-pituitary-adrenal hormonal release during exercise and hot environmental temperatures.

  7. Angiotensin –Converting Enzyme Inhibition or Mineralocorticoid Receptor Blockade Do Not Affect Incidence of Atrial Fibrillation in Patients Undergoing Cardiac Surgery

    PubMed Central

    Pretorius, Mias; Murray, Katherine T.; Yu, Chang; Byrne, John G.; Billings, Frederic T.; Petracek, Michael R.; Greelish, James P.; Hoff, Steven J.; Ball, Stephen K.; Mishra, Vineet; Body, Simon C.; Brown, Nancy J.

    2013-01-01

    Objective This study tested the hypothesis that interruption of the renin-angiotensin system with either an angiotensin-converting enzyme inhibitor or a mineralocorticoid receptor antagonist will decrease the incidence of atrial fibrillation after cardiac surgery. Design Randomized double-blind placebo-controlled study. Setting University affiliated hospitals. Patients Four-hundred and forty-five adult patients in normal sinus rhythm undergoing elective cardiac surgery. Interventions One week to four days prior to surgery, patients were randomized to treatment with placebo, ramipril (2.5 mg the first three days followed by 5mg/day, with the dose reduced to 2.5mg/d on the first postoperative day only), or spironolactone (25 mg/day). Measurements The primary endpoint was the occurrence of electrocardiographically confirmed postoperative atrial fibrillation. Secondary endpoints included acute renal failure, hyperkalemia, the incidence of hypotension, length of hospital stay, stroke, and death. Main Results The incidence of atrial fibrillation was 27.2% in the placebo group, 27.8% in the ramipril group, and 25.9% in the spironolactone group (P=0.95). Patients in the ramipril (0.7%) or spironolactone (0.7%) group were less likely to develop acute renal failure than those randomized to placebo (5.4%, P=0.006). Patients in the placebo group tended to be hospitalized longer than those in the ramipril or spironolactone group (6.8±8.2 days versus 5.7±3.2 and 5.8±3.4 days, respectively, P=0.08 for the comparison of placebo versus the active treatment groups using log-rank test). Compared to patients in the placebo group, patients in the spironolactone group were extubated sooner after surgery (576.4±761.5 minutes versus 1091.3±3067.3 minutes, P=0.04). Conclusions Neither angiotensin-converting enzyme inhibition nor mineralocorticoid receptor blockade decreased the primary outcome of postoperative atrial fibrillation. Treatment with an angiotensin-converting enzyme

  8. Effects of activation and blockade of dopamine receptors on the extinction of a passive avoidance reaction in mice with a depressive-like state.

    PubMed

    Dubrovina, N I; Zinov'eva, D V

    2010-01-01

    Learning and extinction of a conditioned passive avoidance reaction resulting from neuropharmacological actions on dopamine D(1) and D(2) receptors were demonstrated to be specific in intact mice and in mice with a depressive-like state. Learning was degraded only after administration of the D(2) receptor antagonist sulpiride and was independent of the initial functional state of the mice. In intact mice, activation of D(2) receptors with quinpirole led to a deficit of extinction, consisting of a reduction in the ability to acquire new inhibitory learning in conditions associated with the disappearance of the expected punishment. In mice with the "behavioral despair" reaction, characterized by delayed extinction, activation of D(1) receptors with SKF38393 normalized this process, while the D(2) agonist was ineffective. A positive effect consisting of accelerated extinction of the memory of fear of the dark ("dangerous") sector of the experimental chamber was also seen on blockade of both types of dopamine receptor.

  9. [Effects of activation and blockade of dopamine receptors on extinction of passive avoidance response in mice with depressive-like state].

    PubMed

    Dubrovina, N I; Zinov'eva, D V

    2008-01-01

    Selectivity of training and extinction of passive avoidance response caused by pharmacological influences on D1 and D2 dopamine receptors in intact mice and mice in depressive-like state was shown. Training was impaired only by administration of D2 receptor antagonist sulpiride and did not depend on the initial functional condition of mice. In intact mice, activation of D2 receptors by quinpirole evoked deficiency of extinction, i.e., impairment of the capability of new inhibitory training under conditions of disappearance of the expected punishment. In mice with reaction of "behavioral despair" characterized by a delay of extinction, activation of D1 receptors by SKF38393 normalized this process (as distinct from the inefficiency of D2 agonist). The positive effect of acceleration of fear memory extinction was revealed also under conditions of blockade of D1 and D2 dopamine receptors.

  10. [Sympathetic responsiveness and antihypertensive effect of beta-receptor blockade in essential hypertension: the effect of atenolol (author's transl)].

    PubMed

    Philipp, T; Cordes, U; Distler, A

    1977-04-15

    Plasmin noradrenaline concentration after bicycle exercise (200 W for 2 min), compared with base line concentration, was used as an index of sympathetic responsiveness in patients with essential hypertension. Atenolol (JCI 66082, a "cardioselective" beta-blocker) was given in a daily dose of 200 mg to 16 patients for five weeks. This caused a decrease in supine blood pressure of 37/23 and, on standing, of 36/25 mm Hg compared with the placebo period. There was a significant correlation between the ratio of the increase in plasma noradrenaline concentration on exercise over its base line concentration and the subsequent fall in mean arterial pressure (r=0.840; P less than 0.001). There was a less significant correlation between plasma renin concentration and subsequent decrease in mean arterial pressure (r=0.542; P less than 0.05). Administrations of atenolol caused a rise in plasma noradrenaline both on lying and after exercise (P less than 0.0125), and a fall in plasma renin concentration (P less than 0.01). The results suggest that the antihypertensive effect of atenolol is related to the responsiveness of the sympathetic nervous sytem. Adrenergic activity is apparently an important determinant of blood pressure response to beta-blockade.

  11. Blockade of glucocorticoid receptors with ORG 34116 does not normalize stress-induced symptoms in male tree shrews.

    PubMed

    Van Kampen, Marja; De Kloet, E Ronald; Flügge, Gabriele; Fuchs, Eberhard

    2002-12-20

    Glucocorticoid receptors play an important role in the regulation of the activity of the hypothalamo-pituitary-adrenal axis, and are thought to be involved in the pathophysiology of depressive disorders. The present study investigated the effect of the specific glucocorticoid receptor antagonist ORG 34116 (a substituted 11,21 bisarylsteroid compound) in the tree shrew (Tupaia belangeri) chronic psychosocial stress model, an established animal model for depressive disorders. Animals were stressed for 10 days before treatment with ORG 34116 started (25 mg/kg p.o. for 28 days). Stress induced a decrease in body weight, which just failed significance, whereas ORG 34116 did not affect body weight in stress and control animals. ORG 34116 enhanced the stress-induced increase in the concentration of urinary-free cortisol, although no differences between the different experimental groups existed during the last week of treatment. In stressed animals, ORG 34116 did not affect marking behavior, but decreased locomotor activity. Post mortem analysis of 5-HT(1A) receptors revealed a decreased affinity of 3[H]-8-OH-DPAT (3[H]-8-hydroxy-2-[di-n-propylamino]tetralin) binding sites in the hippocampus of animals treated with the glucocorticoid receptor antagonist. In conclusion, under our experimental conditions, the glucocorticoid receptor antagonist ORG 34116 did not normalize the depressive-like symptoms in the psychosocial stress model of male tree shrews. This finding, however, does not exclude that specific central, neuroendocrine and behavioral features are affected by the compound.

  12. Inhibition of angiogenesis by selective estrogen receptor modulators through blockade of cholesterol trafficking rather than estrogen receptor antagonism.

    PubMed

    Shim, Joong Sup; Li, Ruo-Jing; Lv, Junfang; Head, Sarah A; Yang, Eun Ju; Liu, Jun O

    2015-06-28

    Selective estrogen receptor modulators (SERM) including tamoxifen are known to inhibit angiogenesis. However, the underlying mechanism, which is independent of their action on the estrogen receptor (ER), has remained largely unknown. In the present study, we found that tamoxifen and other SERM inhibited cholesterol trafficking in endothelial cells, causing a hyper-accumulation of cholesterol in late endosomes/lysosomes. Inhibition of cholesterol trafficking by tamoxifen was accompanied by abnormal subcellular distribution of vascular endothelial growth factor receptor-2 (VEGFR2) and inhibition of the terminal glycosylation of the receptor. Tamoxifen also caused perinuclear positioning of lysosomes, which in turn trapped the mammalian target of rapamycin (mTOR) in the perinuclear region of endothelial cells. Abnormal distribution of VEGFR2 and mTOR and inhibition of VEGFR2 and mTOR activities by tamoxifen were significantly reversed by addition of cholesterol-cyclodextrin complex to the culture media of endothelial cells. Moreover, high concentrations of tamoxifen inhibited endothelial and breast cancer cell proliferation in a cholesterol-dependent, but ER-independent, manner. Together, these results unraveled a previously unrecognized mechanism of angiogenesis inhibition by tamoxifen and other SERM, implicating cholesterol trafficking as an attractive therapeutic target for cancer treatment.

  13. D2 receptor blockade by flunarizine and cinnarizine explains extrapyramidal side effects. A SPECT study.

    PubMed

    Brücke, T; Wöber, C; Podreka, I; Wöber-Bingöl, C; Asenbaum, S; Aull, S; Wenger, S; Ilieva, D; Harasko-van der Meer, C; Wessely, P

    1995-05-01

    Twenty-six patients under treatment with the calcium channel blockers flunarizine (Fz) or cinnarizine (Cz) were examined-with single-photon emission computed tomography using [123I]iodobenzamide as a ligand. The striatal dopamine D2 receptor-binding potential was determined and found to be reduced by 14 to 63% (39.5 +/- 15.0%; p < 0.0001) in patients compared with age-matched control values. This reduction was larger in 12 patients with extrapyramidal symptoms and was only slowly reversible after discontinuation of treatment. Patients treated for > 6 months had significantly larger reductions than patients treated for a shorter period. Parkinsonian symptoms were only seen in patients older than 50 years. Our findings prove a neuroleptic-like action of Fz and Cz, which seems to be the major reason for their extrapyramidal side effects. Older age and long-term treatment are predisposing factors for these effects.

  14. Selective endothelin receptor blockade in resistant hypertension: results of the DORADO trial.

    PubMed

    Grassi, Guido

    2011-01-01

    Effective treatment of resistant hypertension still remains an unmet goal of antihypertensive drug treatment. The DORADO trial recently evaluated the efficacy and safety profile of the selective endothelin receptor blocker darusentan in almost 400 hypertensive patients treated with more than four antihypertensive drugs (including a diuretic) but without effective blood pressure control. The trial results show that > 50% of patients treated with the drug exhibit clinical blood pressure < 140/90 mmHg and well-controlled ambulatory blood pressure values. Darusentan, however, was associated with a high incidence of peripheral edema and fluid retention, a side effect that may reduce the safety profile of the drug and its tolerability. Although these data are promising, the drug requires further evaluation, with particularly regard to the long term.

  15. Glucocorticoid receptor blockade inhibits brain cell addition and aggressive signaling in electric fish, Apteronotus leptorhynchus.

    PubMed

    Dunlap, Kent D; Jashari, Denisa; Pappas, Kristina M

    2011-08-01

    When animals are under stress, glucocorticoids commonly inhibit adult neurogenesis by acting through glucocorticoid receptors (GRs). However, in some cases, conditions that elevate glucocorticoids promote adult neurogenesis, and the role of glucocorticoid receptors in these circumstances is not well understood. We examined the involvement of GRs in social enhancement of brain cell addition and aggressive signaling in electric fish, Apteronotus leptorhynchus. In this species, long-term social interaction simultaneously elevates plasma cortisol, enhances brain cell addition and increases production of aggressive electrocommunication signals ("chirps"). We implanted isolated and paired fish with capsules containing nothing (controls) or the GR antagonist, RU486, recorded chirp production and locomotion for 7d, and measured the density of newborn cells in the periventricular zone. Compared to isolated controls, paired controls showed elevated chirping in two phases: much higher chirp rates in the first 5h and moderately higher nocturnal rates thereafter. Treating paired fish with RU486 reduced chirp rates in both phases to those of isolated fish, demonstrating that GR activation is crucial for socially induced chirping. Neither RU486 nor social interaction affected locomotion. RU486 treatment to paired fish had a partial effect on cell addition: paired RU486 fish had less cell addition than paired control fish but more than isolated fish. This suggests that cortisol activation of GRs contributes to social enhancement of cell addition but works in parallel with another GR-independent mechanism. RU486 also reduced cell addition in isolated fish, indicating that GRs participate in the regulation of cell addition even when cortisol levels are low.

  16. Due to interleukin-6 type cytokine redundancy only glycoprotein 130 receptor blockade efficiently inhibits myeloma growth

    PubMed Central

    Burger, Renate; Günther, Andreas; Klausz, Katja; Staudinger, Matthias; Peipp, Matthias; Penas, Eva Maria Murga; Rose-John, Stefan; Wijdenes, John; Gramatzki, Martin

    2017-01-01

    Interleukin-6 has an important role in the pathophysiology of multiple myeloma where it supports the growth and survival of the malignant plasma cells in the bone marrow. It belongs to a family of cytokines which use the glycoprotein 130 chain for signal transduction, such as oncostatin M or leukemia inhibitory factor. Targeting interleukin-6 in plasma cell diseases is currently evaluated in clinical trials with monoclonal antibodies. Here, efforts were made to elucidate the contribution of interleukin-6 and glycoprotein 130 signaling in malignant plasma cell growth in vivo. In the xenograft severe combined immune deficiency model employing our interleukin-6-dependent plasma cell line INA-6, the lack of human interleukin-6 induced autocrine interleukin-6 production and a proliferative response to other cytokines of the glycoprotein 130 family. Herein, mice were treated with monoclonal antibodies against human interleukin-6 (elsilimomab/B-E8), the interleukin-6 receptor (B-R6), and with an antibody blocking glycoprotein 130 (B-R3). While treatment of mice with interleukin-6 and interleukin-6 receptor antibodies resulted in a modest delay in tumor growth, the development of plasmacytomas was completely prevented with the anti-glycoprotein 130 antibody. Importantly, complete inhibition was also achieved using F(ab’)2-fragments of monoclonal antibody B-R3. Tumors harbor activated signal transducer and activator of transcription 3, and in vitro, the antibody inhibited leukemia inhibitory factor stimulated signal transducer and activator of transcription 3 phosphorylation and cell growth, while being less effective against interleukin-6. In conclusion, the growth of INA-6 plasmacytomas in vivo under interleukin-6 withdrawal remains strictly dependent on glycoprotein 130, and other glycoprotein 130 cytokines may substitute for interleukin-6. Antibodies against glycoprotein 130 are able to overcome this redundancy and should be explored for a possible therapeutic window

  17. Original nootropic drug noopept prevents memory deficit in rats with muscarinic and nicotinic receptor blockade.

    PubMed

    Radionova, K S; Belnik, A P; Ostrovskaya, R U

    2008-07-01

    Antiamnesic activity of Noopept was studied on the original three-way model of conditioned passive avoidance response, which allows studying spatial component of memory. Cholinoceptor antagonists of both types (scopolamine and mecamylamine) decreased entry latency and reduced the probability for selection of the safe compartment. Noopept abolished the antiamnesic effect of cholinoceptor antagonists and improved spatial preference.

  18. Blockade of mesolimbic dopamine D3 receptors inhibits stress-induced reinstatement of cocaine-seeking in rats

    PubMed Central

    Gilbert, Jeremy; Campos, Arlene C.; Kline, Nicole; Ashby, Charles R.; Hagan, Jim J.; Heidbreder, Christian A.; Gardner, Eliot L.

    2013-01-01

    Rationale The dopamine (DA) D3 receptor is preferentially expressed in the mesolimbic system. We have previously shown that selective D3 receptor blockade by the novel D3 antagonist SB-277011A inhibits cocaine’s reinforcing action and cocaine-induced reinstatement of cocaine-seeking behavior. Objective In the present study, we investigated whether SB-277011A similarly inhibits stress-induced reinstatement of cocaine-seeking behavior. Methods Rats were allowed to self-administer cocaine (0.5 mg/kg per infusion, 3 h per session) for 10–14 days, followed by a once-daily extinction session for 7–14 days during which saline was substituted for cocaine. Extinction criteria were fewer than ten lever-presses per 3-h session for at least 3 consecutive days. After cocaine-seeking behavior was extinguished, each animal was tested twice for footshock-stress-induced reinstatement, once with vehicle (25% hydroxypropyl-β-cyclodextrin) and once with one of three doses of SB-277011A in counterbalanced fashion. Results During the last 3 days of cocaine self-administration (SA), active lever-presses were approximately 100 per session under fixed-ratio 2 reinforcement (~25 mg/kg cocaine per session). After extinction, intermittent footshock (10 min, 0.5 mA, 0.5 s on with a mean inter-shock interval of 40 s) robustly reinstated the cocaine-seeking behavior (8.4±3.6 active lever-presses in last extinction session to 35.3±5.2 in animals after footshock stress). Intraperitoneal (IP) injections of SB-277011A (3, 6, and 12 mg/kg) dose-dependently blocked stress-induced reinstatement of cocaine-seeking. Reinstatement was also blocked by microinjections of SB-277011A (1.5 μg/0.5 μl per side) bilaterally into the nucleus accumbens, but not into the dorsal striatum. Conclusions The mesolimic DA D3 receptor plays an important role in mediating stress-induced reinstatement. PMID:15083257

  19. In vivo blockade of α1-adrenergic receptors mitigates stress-disturbed cAMP and cGMP signaling in Leydig cells.

    PubMed

    Stojkov, Natasa J; Baburski, Aleksandar Z; Bjelic, Maja M; Sokanovic, Srdjan J; Mihajlovic, Aleksandar I; Drljaca, Dragana M; Janjic, Marija M; Kostic, Tatjana S; Andric, Silvana A

    2014-01-01

    The molecular mechanism of stress-associated reproductive dysfunction is complex and largely unknown. This study was designed to systematically analyze molecular effects of systemic in vivo blockade of α1-adrenergic receptors (α1-ADRs) on stress-induced disturbance of cAMP/cGMP signaling in testosterone-producing Leydig cells using the following parameters (i) level of circulating stress hormones, LH and testosterone; (ii) level of main molecular markers of Leydig cell functionality (testosterone, Insl3, cAMP); (iii) expression of cAMP signaling (cAMP 'producers'/'effectors'/'removers') and (iv) expression of NO-cGMP signaling (NO-cGMP 'producers'/'effectors'/'removers'). The results showed that oral administration of α1-ADR blocker before stress increased cGMP and diminished stress-reduced cAMP production in Leydig cells. In the same cells, stress-induced effects on cAMP/cGMP signaling pathways elements were changed. Sustained in vivo α1-ADR blockade completely abolished stress-increased transcription of most abundantly expressed phosphodiesterase that remove cAMP (Pde4b) and potentiated stress-increased expression of PRKA, the main stimulator of Leydig cell steroidogenesis. In the same Leydig cells, stress-decreased NOS3 expression was abolished, while stress-increased GUCY1 (cGMP 'producer') and PRKG1 (cGMP 'effector') were potentiated. It is possible that all molecules mentioned could contribute, at least in part, in recovery of Leydig cell testosterone production. Presented data provide new role of α1-ADRs in stress-triggered disturbance of cAMP/cGMP signaling, and new molecular insights into the relationship between stress and mammalian reproduction. Regardless of whether the effects of α1-blocker + stress are direct or indirect, the results are important in terms of human reproductive health and the wide use of α1-ADR antagonists, alone or in combination, to treat post-traumatic stress disorders, hypertension, benign prostatic hyperplasia symptoms and

  20. Decreased prefrontal cortex dopamine activity following adolescent social defeat in male rats: role of dopamine D2 receptors

    PubMed Central

    Watt, Michael J.; Roberts, Christina L.; Scholl, Jamie L.; Meyer, Danielle L.; Miiller, Leah C.; Barr, Jeffrey L.; Novick, Andrew M.; Renner, Kenneth J.; Forster, Gina L.

    2014-01-01

    Rationale Adverse social experience in adolescence causes reduced medial prefrontal cortex (mPFC) dopamine (DA) and associated behavioral deficits in early adulthood. Objective To determine whether mPFC DA hypofunction following social stress is specific to adolescent experience, and if this results from stress-induced DA D2 receptor activation. Materials and Methods Male rats exposed to repeated social defeat during adolescence or adulthood had mPFC DA activity sampled 17 days later. Separate experiments used freely-moving microdialysis to measure mPFC DA release in response to adolescent defeat exposure. At P40, 49 and 56 mPFC DA turnover was assessed to identify when DA activity decreased in relation to the adolescent defeat experience. Finally, non-defeated adolescent rats received repeated intra-mPFC infusions of the D2 receptor agonist quinpirole, while another adolescent group received intra-mPFC infusions of the D2 antagonist amisulpride before defeat exposure. Results Long-term decreases or increases in mPFC DA turnover were observed following adolescent or adult defeat, respectively. Adolescent defeat exposure elicits sustained increases in mPFC DA release, and DA turnover remains elevated beyond the stress experience before declining to levels below normal at P56. Activation of mPFC D2 receptors in non-defeated adolescents decreases DA activity in a similar manner to that caused by adolescent defeat, while defeat-induced reductions in mPFC DA activity are prevented by D2 receptor blockade. Conclusions Both the developing and mature PFC DA systems are vulnerable to social stress, but only adolescent defeat causes DA hypofunction. This appears to result in part from stress-induced activation of mPFC D2 autoreceptors. PMID:24271009

  1. Error correction in latent inhibition and its disruption by opioid receptor blockade with naloxone.

    PubMed

    Leung, Hiu T; Killcross, A S; Westbrook, R Frederick

    2013-11-01

    Latent inhibition refers to the retardation in the development of conditioned responding when a pre-exposed stimulus is used to signal an unconditioned stimulus. This effect is described by error-correction models as an attentional deficit and is commonly used as an animal model of schizophrenia. A series of experiments studied the role of error-correction mechanism in latent inhibition and its interaction with the endogenous opioid system. Systemic administration of the competitive opioid receptor antagonist naloxone before rats were pre-exposed to a target stimulus prevented latent inhibition of its subsequent fear conditioning; it was without effect on a non-pre-exposed stimulus and did not produce state-dependent learning (Experiments 1a and 1b). Naloxone did not reverse the latent inhibitory effect already accrued to a pre-exposed target. However, it did prevent the enhancement of latent inhibition by a long retention interval interpolated between its initial exposure and re-exposure (Experiment 2) or by a novel stimulus compounded with the pre-exposed target during re-exposure (Experiment 3). These results provide evidence that attentional loss in latent inhibition is instructed by an opioid-mediated error signal which diminishes with repeated stimulus exposures but recovers with the passage of time or reintroduction of novelty.

  2. Error Correction in Latent Inhibition and its Disruption by Opioid Receptor Blockade with Naloxone

    PubMed Central

    Leung, Hiu T; Killcross, A S; Westbrook, R Frederick

    2013-01-01

    Latent inhibition refers to the retardation in the development of conditioned responding when a pre-exposed stimulus is used to signal an unconditioned stimulus. This effect is described by error-correction models as an attentional deficit and is commonly used as an animal model of schizophrenia. A series of experiments studied the role of error-correction mechanism in latent inhibition and its interaction with the endogenous opioid system. Systemic administration of the competitive opioid receptor antagonist naloxone before rats were pre-exposed to a target stimulus prevented latent inhibition of its subsequent fear conditioning; it was without effect on a non-pre-exposed stimulus and did not produce state-dependent learning (Experiments 1a and 1b). Naloxone did not reverse the latent inhibitory effect already accrued to a pre-exposed target. However, it did prevent the enhancement of latent inhibition by a long retention interval interpolated between its initial exposure and re-exposure (Experiment 2) or by a novel stimulus compounded with the pre-exposed target during re-exposure (Experiment 3). These results provide evidence that attentional loss in latent inhibition is instructed by an opioid-mediated error signal which diminishes with repeated stimulus exposures but recovers with the passage of time or reintroduction of novelty. PMID:23748224

  3. Chronic CRF1 receptor blockade reduces heroin intake escalation and dependence-induced hyperalgesia.

    PubMed

    Park, Paula E; Schlosburg, Joel E; Vendruscolo, Leandro F; Schulteis, Gery; Edwards, Scott; Koob, George F

    2015-03-01

    Opioids represent effective drugs for the relief of pain, yet chronic opioid use often leads to a state of increased sensitivity to pain that is exacerbated during withdrawal. A sensitization of pain-related negative affect has been hypothesized to closely interact with addiction mechanisms. Neuro-adaptive changes occur as a consequence of excessive opioid exposure, including a recruitment of corticotropin-releasing factor (CRF) and norepinephrine (NE) brain stress systems. To better understand the mechanisms underlying the transition to dependence, we determined the effects of functional antagonism within these two systems on hyperalgesia-like behavior during heroin withdrawal utilizing models of both acute and chronic dependence. We found that passive or self-administered heroin produced a significant mechanical hypersensitivity. During acute opioid dependence, systemic administration of the CRF1 receptor antagonist MPZP (20 mg/kg) alleviated withdrawal-induced mechanical hypersensitivity. In contrast, several functional adrenergic system antagonists (clonidine, prazosin, propranolol) failed to alter mechanical hypersensitivity in this state. We then determined the effects of chronic MPZP or clonidine treatment on extended access heroin self-administration and found that MPZP, but not clonidine, attenuated escalation of heroin intake, whereas both drugs alleviated chronic dependence-associated hyperalgesia. These findings suggest that an early potentiation of CRF signaling occurs following opioid exposure that begins to drive both opioid-induced hyperalgesia and eventually intake escalation.

  4. Chronic CRF1 Receptor Blockade Reduces Heroin Intake Escalation and Dependence-Induced Hyperalgesia

    PubMed Central

    Park, Paula E.; Schlosburg, Joel E.; Vendruscolo, Leandro F.; Schulteis, Gery; Edwards, Scott; Koob, George F.

    2014-01-01

    Opioids represent effective drugs for the relief of pain, yet chronic opioid use often leads to a state of increased sensitivity to pain that is exacerbated during withdrawal. A sensitization of pain-related negative affect has been hypothesized to closely interact with addiction mechanisms. Neuroadaptive changes occur as a consequence of excessive opioid exposure, including a recruitment of corticotropin-releasing factor (CRF) and norepinephrine (NE) brain stress systems. To better understand the mechanisms underlying the transition to dependence, we determined the effects of functional antagonism within these two systems on hyperalgesia-like behavior during heroin withdrawal utilizing models of both acute and chronic dependence. We found that passive or self-administered heroin produced a significant mechanical hypersensitivity. During acute opioid dependence, systemic administration of the CRF1 receptor antagonist MPZP (20 mg/kg) alleviated withdrawal-induced mechanical hypersensitivity. In contrast, several functional adrenergic system antagonists (clonidine, prazosin, propranolol) failed to alter mechanical hypersensitivity in this state. We then determined the effects of chronic MPZP or clonidine treatment on extended access heroin self-administration and found that MPZP, but not clonidine, attenuated escalation of heroin intake, whereas both drugs alleviated chronic dependence-associated hyperalgesia. These findings suggest that an early potentiation of CRF signaling occurs following opioid exposure that begins to drive both opioid-induced hyperalgesia and eventually intake escalation. PMID:24330252

  5. The Impact of NMDA Receptor Blockade on Human Working Memory-Related Prefrontal Function and Connectivity

    PubMed Central

    Driesen, Naomi R; McCarthy, Gregory; Bhagwagar, Zubin; Bloch, Michael H; Calhoun, Vincent D; D'Souza, Deepak C; Gueorguieva, Ralitza; He, George; Leung, Hoi-Chung; Ramani, Ramachandran; Anticevic, Alan; Suckow, Raymond F; Morgan, Peter T; Krystal, John H

    2013-01-01

    Preclinical research suggests that N-methyl-D-aspartate glutamate receptors (NMDA-Rs) have a crucial role in working memory (WM). In this study, we investigated the role of NMDA-Rs in the brain activation and connectivity that subserve WM. Because of its importance in WM, the lateral prefrontal cortex, particularly the dorsolateral prefrontal cortex and its connections, were the focus of analyses. Healthy participants (n=22) participated in a single functional magnetic resonance imaging session. They received saline and then the NMDA-R antagonist ketamine while performing a spatial WM task. Time-course analysis was used to compare lateral prefrontal activation during saline and ketamine administration. Seed-based functional connectivity analysis was used to compare dorsolateral prefrontal connectivity during the two conditions and global-based connectivity was used to test for laterality in these effects. Ketamine reduced accuracy on the spatial WM task and brain activation during the encoding and early maintenance (EEM) period of task trials. Decrements in task-related activation during EEM were related to performance deficits. Ketamine reduced connectivity in the DPFC network bilaterally, and region-specific reductions in connectivity were related to performance. These results support the hypothesis that NMDA-Rs are critical for WM. The knowledge gained may be helpful in understanding disorders that might involve glutamatergic deficits such as schizophrenia and developing better treatments. PMID:23856634

  6. The impact of NMDA receptor blockade on human working memory-related prefrontal function and connectivity.

    PubMed

    Driesen, Naomi R; McCarthy, Gregory; Bhagwagar, Zubin; Bloch, Michael H; Calhoun, Vincent D; D'Souza, Deepak C; Gueorguieva, Ralitza; He, George; Leung, Hoi-Chung; Ramani, Ramachandran; Anticevic, Alan; Suckow, Raymond F; Morgan, Peter T; Krystal, John H

    2013-12-01

    Preclinical research suggests that N-methyl-D-aspartate glutamate receptors (NMDA-Rs) have a crucial role in working memory (WM). In this study, we investigated the role of NMDA-Rs in the brain activation and connectivity that subserve WM. Because of its importance in WM, the lateral prefrontal cortex, particularly the dorsolateral prefrontal cortex and its connections, were the focus of analyses. Healthy participants (n=22) participated in a single functional magnetic resonance imaging session. They received saline and then the NMDA-R antagonist ketamine while performing a spatial WM task. Time-course analysis was used to compare lateral prefrontal activation during saline and ketamine administration. Seed-based functional connectivity analysis was used to compare dorsolateral prefrontal connectivity during the two conditions and global-based connectivity was used to test for laterality in these effects. Ketamine reduced accuracy on the spatial WM task and brain activation during the encoding and early maintenance (EEM) period of task trials. Decrements in task-related activation during EEM were related to performance deficits. Ketamine reduced connectivity in the DPFC network bilaterally, and region-specific reductions in connectivity were related to performance. These results support the hypothesis that NMDA-Rs are critical for WM. The knowledge gained may be helpful in understanding disorders that might involve glutamatergic deficits such as schizophrenia and developing better treatments.

  7. Effect of IL-17 receptor A blockade with brodalumab in inflammatory diseases.

    PubMed

    Nirula, Ajay; Nilsen, Jon; Klekotka, Paul; Kricorian, Greg; Erondu, Ngozi; Towne, Jennifer E; Russell, Chris B; Martin, David A; Budelsky, Alison L

    2016-12-01

    IL-17 cytokines are expressed by a variety of cells and mediate host defence against extracellular pathogens. IL-17 is upregulated at sites of inflammation and can synergize with other cytokines, such as TNF-α, to amplify the inflammatory response. Activation of these signalling pathways has been hypothesized to contribute to the underlying pathogenesis of several inflammatory diseases, including psoriasis, RA, PsA and asthma. Thus the IL-17 signalling pathway is an attractive target for the development of therapeutic agents to modulate aberrant inflammatory responses. This review of the clinical development of therapeutic agents that target IL-17 signalling pathways in inflammatory diseases focuses on brodalumab, a human anti-IL-17 receptor A mAb. The cumulative findings of early clinical studies with anti-IL-17 agents, including brodalumab, secukinumab and ixekizumab, provide strong evidence for the role of IL-17 signalling in the pathophysiology of certain inflammatory diseases and support the potential use of these agents in treating these diseases. © The Author 2016. Published by Oxford University Press on behalf of the British Society for Rheumatology. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  8. Central serotonin(2B) receptor blockade inhibits cocaine-induced hyperlocomotion independently of changes of subcortical dopamine outflow.

    PubMed

    Devroye, Céline; Cathala, Adeline; Di Marco, Barbara; Caraci, Filippo; Drago, Filippo; Piazza, Pier Vincenzo; Spampinato, Umberto

    2015-10-01

    The central serotonin2B receptor (5-HT2BR) is currently considered as an interesting pharmacological target for improved treatment of drug addiction. In the present study, we assessed the effect of two selective 5-HT2BR antagonists, RS 127445 and LY 266097, on cocaine-induced hyperlocomotion and dopamine (DA) outflow in the nucleus accumbens (NAc) and the dorsal striatum of freely moving rats. The peripheral administration of RS 127445 (0.16 mg/kg, i.p.) or LY 266097 (0.63 mg/kg, i.p.) significantly reduced basal DA outflow in the NAc shell, but had no effect on cocaine (10 mg/kg, i.p.)-induced DA outflow in this brain region. Also, RS 127445 failed to modify both basal and cocaine-induced DA outflow in the NAc core and the dorsal striatum. Conversely, both 5-HT2BR antagonists reduced cocaine-induced hyperlocomotion. Furthermore, RS 127445 as well as the DA-R antagonist haloperidol (0.1 mg/kg, i.p.) reduced significantly the late-onset hyperlocomotion induced by the DA-R agonist quinpirole (0.5 mg/kg, s.c.). Altogether, these results demonstrate that 5-HT2BR blockade inhibits cocaine-induced hyperlocomotion independently of changes of subcortical DA outflow. This interaction takes place downstream to DA neurons and could involve an action at the level of dorsostriatal and/or NAc DA transmission, in keeping with the importance of these brain regions in the behavioural responses of cocaine. Overall, this study affords additional knowledge into the regulatory control exerted by the 5-HT2BR on ascending DA pathways, and provides additional support to the proposed role of 5-HT2BRs as a new pharmacological target in drug addiction. Copyright © 2015 Elsevier Ltd. All rights reserved.

  9. Attenuation of Myocardial Injury by HMGB1 Blockade during Ischemia/Reperfusion Is Toll-Like Receptor 2-Dependent

    PubMed Central

    Iskandar, Franziska; Habeck, Katharina; Zimmermann, René; Schumann, Ralf R.; Koch, Alexander

    2013-01-01

    Genetic or pharmacological ablation of toll-like receptor 2 (TLR2) protects against myocardial ischemia/reperfusion injury (MI/R). However, the endogenous ligand responsible for TLR2 activation has not yet been detected. The objective of this study was to identify HMGB1 as an activator of TLR2 signalling during MI/R. C57BL/6 wild-type (WT) or TLR2−/−-mice were injected with vehicle, HMGB1, or HMGB1 BoxA one hour before myocardial ischemia (30 min) and reperfusion (24 hrs). Infarct size, cardiac troponin T, leukocyte infiltration, HMGB1 release, TLR4-, TLR9-, and RAGE-expression were quantified. HMGB1 plasma levels were measured in patients undergoing coronary artery bypass graft (CABG) surgery. HMGB1 antagonist BoxA reduced cardiomyocyte necrosis during MI/R in WT mice, accompanied by reduced leukocyte infiltration. Injection of HMGB1 did, however, not increase infarct size in WT animals. In TLR2−/−-hearts, neither BoxA nor HMGB1 affected infarct size. No differences in RAGE and TLR9 expression could be detected, while TLR2−/−-mice display increased TLR4 and HMGB1 expression. Plasma levels of HMGB1 were increased MI/R in TLR2−/−-mice after CABG surgery in patients carrying a TLR2 polymorphism (Arg753Gln). We here provide evidence that absence of TLR2 signalling abrogates infarct-sparing effects of HMGB1 blockade. PMID:24371373

  10. Beyond aggression: Androgen-receptor blockade modulates social interaction in wild meerkats.

    PubMed

    delBarco-Trillo, Javier; Greene, Lydia K; Goncalves, Ines Braga; Fenkes, Miriam; Wisse, Jillian H; Drewe, Julian A; Manser, Marta B; Clutton-Brock, Tim; Drea, Christine M

    2016-02-01

    In male vertebrates, androgens are inextricably linked to reproduction, social dominance, and aggression, often at the cost of paternal investment or prosociality. Testosterone is invoked to explain rank-related reproductive differences, but its role within a status class, particularly among subordinates, is underappreciated. Recent evidence, especially for monogamous and cooperatively breeding species, suggests broader androgenic mediation of adult social interaction. We explored the actions of androgens in subordinate, male members of a cooperatively breeding species, the meerkat (Suricata suricatta). Although male meerkats show no rank-related testosterone differences, subordinate helpers rarely reproduce. We blocked androgen receptors, in the field, by treating subordinate males with the antiandrogen, flutamide. We monitored androgen concentrations (via baseline serum and time-sequential fecal sampling) and recorded behavior within their groups (via focal observation). Relative to controls, flutamide-treated animals initiated less and received more high-intensity aggression (biting, threatening, feeding competition), engaged in more prosocial behavior (social sniffing, grooming, huddling), and less frequently initiated play or assumed a 'dominant' role during play, revealing significant androgenic effects across a broad range of social behavior. By contrast, guarding or vigilance and measures of olfactory and vocal communication in subordinate males appeared unaffected by flutamide treatment. Thus, androgens in male meerkat helpers are aligned with the traditional trade-off between promoting reproductive and aggressive behavior at a cost to affiliation. Our findings, based on rare endocrine manipulation in wild mammals, show a more pervasive role for androgens in adult social behavior than is often recognized, with possible relevance for understanding tradeoffs in cooperative systems.

  11. The impact of angiotensin II receptor blockade and the DASH diet on markers of endogenous fibrinolysis.

    PubMed

    Erlinger, T P; Conlin, P R; Macko, R F; Bohannon, A D; Miller, E R; Moore, T J; Svetkey, L P; Appel, L J

    2002-06-01

    Hypertension is associated with impaired fibrinolysis. Both angiotensin receptor blockers (ARB) and the DASH (Dietary Approaches to Stop Hypertension) diet effectively lower blood pressure in hypertensive patients. Some evidence suggests that treatment with ARBs could increase fibrinolysis, however, data is conflicting. The impact of the DASH diet on fibrinolytic parameters is not known. Fifty-five hypertensive participants (35 African-American, 20 white) were randomly assigned to receive 8 weeks of either a control diet or the DASH diet. The diets did not differ in sodium content (approximately 3 g/day). Within each diet, individuals were randomly assigned to receive losartan or placebo for 4 weeks in double-blind, cross-over fashion. Tissue plasminogen activator (t-PA) antigen, t-PA activity, plasminogen activator inhibitor-1 (PAI-1) activity and plasma renin activity (PRA) were measured at the end of a 2-week run-in period on the control diet and after each treatment period. The DASH diet did not affect markers of fibrinolysis. Losartan significantly lowered t-PA antigen levels (-1.8 ng/mL, P = 0.045), but had no effect on t-PA or PAI-1 activities. This effect was more pronounced in whites (-4.1 ng/mL (P = 0.003)) compared with African-Americans (-0.3 ng/mL (P = 0.7), P-interaction = 0.03). Results were not materially affected by adjustment for basline values or changes in blood pressure. This study demonstrates that losartan reduces t-PA antigen levels in white, but not African-American hypertensive individuals. In contrast, the DASH diet had no significant effect on markers of fibrinolysis in whites or African-Americans.

  12. Preferential blockade of dioxin-induced activation of the aryl hydrocarbon receptor by Antrodia camphorata.

    PubMed

    Mukai, Mai; Hayakawa, Kunihiro; Okamura, Maro; Tagawa, Yasuhiro; Nakajima, Shotaro; Saito, Yukinori; Takahashi, Shuhei; Yao, Jian; Nishimura, Daisuke; Sugi, Masahito; Matsunaga, Masaji; Kitamura, Masanori

    2009-09-01

    Halogenated and polycyclic aromatic hydrocarbons are widely distributed pollutants in environments. These toxic substances activate the aryl hydrocarbon receptor (AhR) and thereby cause a broad spectrum of pathological changes. Development of AhR inhibitors will be useful for prevention of diseases caused by AhR activation. Using the dioxin responsive element (DRE)-based sensing via secreted alkaline phosphatase (DRESSA), we examined effects of Antrodia camphorata, a mycerial extract, on the activation of AhR by halogenated and polycyclic aromatic hydrocarbons. We found that Antrodia camphorata markedly suppressed activation of AhR triggered by 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). In contrast, activation of AhR by polycyclic aromatic hydrocarbons (benzo[a]pyrene and 3-methylcholanthrene) was inhibited only modestly by this mycelium. Similarly, Antrodia camphorata only mildly attenuated activation of AhR by cigarette smoke that contains polycyclic aromatic hydrocarbons. Consistent with these results, Northern blot analysis revealed that DRE-driven exogenous and endogenous gene expression triggered by TCDD was abolished by Antrodia camphorata, whereas it did not substantially affect DRE-induced transcription triggered by benzo[a]pyrene, 3-methylcholanthrene or cigarette smoke. We also found that the inhibitory effect of Antrodia camphorata on TCDD-induced AhR activation was ascribed to neither down-regulation of AhR, down-regulation of the AhR nuclear translocator, nor up-regulation of the AhR repressor. These results suggest that Antrodia camphorata preferentially inhibits AhR activation and DRE-dependent gene expression triggered by dioxin.

  13. Relative Response Cost Determines the Sensitivity of Instrumental Reward Seeking to Dopamine Receptor Blockade

    PubMed Central

    Ostlund, Sean B; Kosheleff, Alisa R; Maidment, Nigel T

    2012-01-01

    Dopamine is a critical mediator of instrumental reward seeking behavior and appears to have a particularly important role in motivating actions that require considerable effort. As with rewards, response costs can be evaluated in both absolute and relative terms. The current study investigated whether the extent to which instrumental performance is dependent on dopamine transmission is influenced by relative or absolute response cost. Three groups of rats were rewarded for lever pressing on different fixed ratio (FR) schedules that required 1 (FR-1), 10 (FR-10), or 20 (FR-20) presses for each food reward. Rats were then injected systemically with flupentixol, a dopamine receptor antagonist, or vehicle before testing all groups on an intermediate-cost (FR-10) schedule, such that only the relative cost of responding differed across groups. Rats experiencing an upshift in cost (group FR-1/FR-10) showed greater response suppression following flupentixol administration than rats experiencing no shift in cost (group FR-10/FR-10), whereas flupentixol treatment had no effect on rats experiencing a downshift in cost (group FR-20/FR-10). A second round of flupentixol tests was conducted using the rats' maintenance schedules, such that only absolute response costs differed across groups. Here, the pattern was reversed among the groups, in line with previous reports. Specifically, flupentixol had a stronger suppressive effect in group FR-20/FR-20 than in group FR-10/FR-10, and had no detectable effect in group FR-1/FR-1. These findings suggest that response costs are evaluated in both absolute and relative terms and that dopamine has a role in overcoming both kinds of cost. PMID:22805602

  14. Blockade of NMDA receptors in the dorsomedial striatum prevents action-outcome learning in instrumental conditioning.

    PubMed

    Yin, Henry H; Knowlton, Barbara J; Balleine, Bernard W

    2005-07-01

    Although there is consensus that instrumental conditioning depends on the encoding of action-outcome associations, it is not known where this learning process is localized in the brain. Recent research suggests that the posterior dorsomedial striatum (pDMS) may be the critical locus of these associations. We tested this hypothesis by examining the contribution of N-methyl-D-aspartate receptors (NMDARs) in the pDMS to action-outcome learning. Rats with bilateral cannulae in the pDMS were first trained to perform two actions (left and right lever presses), for sucrose solution. After the pre-training phase, they were given an infusion of the NMDA antagonist 2-amino-5-phosphonopentanoic acid (APV, 1 mg/mL) or artificial cerebral spinal fluid (ACSF) before a 30-min session in which pressing one lever delivered food pellets and pressing the other delivered fruit punch. Learning during this session was tested the next day by sating the animals on either the pellets or fruit punch before assessing their performance on the two levers in extinction. The ACSF group selectively reduced responding on the lever that, in training, had earned the now devalued outcome, whereas the APV group did not. Experiment 2 replicated the effect of APV during the critical training session but found no effect of APV given after acquisition and before test. Furthermore, Experiment 3 showed that the effect of APV on instrumental learning was restricted to the pDMS; infusion into the dorsolateral striatum did not prevent learning. These experiments provide the first direct evidence that, in instrumental conditioning, NMDARs in the dorsomedial striatum are involved in encoding action-outcome associations.

  15. The effect of β receptor blockade through propranolol on corneal neovascularization.

    PubMed

    Simavli, Hüseyin; Erdurmus, Mesut; Terzi, Elçin Hakan; Bucak, Yasin Yücel; Önder, Halil İbrahim; Kükner, Ahmet Şahap

    2014-10-01

    To evaluate the inhibitory effects of propranolol, a nonselective and lipophilic β-adrenergic receptor blocker, on alkali-induced corneal neovascularization (NV). Corneal NV was induced in 24 eyes of 24 Wistar rats using NaOH. Following alkali burn, animals were randomized into 4 groups according to topical treatment. Group I received 0.9% NaCl, Group II received preservative-free dexamethasone sodium phosphate 1 mg/mL, Group III received propranolol hydrochloride 1 mg/mL, and Group IV received 0.5 mg/mL propranolol hydrochloride drops twice a day for 7 days. The inhibitory effects of the drugs were compared as the percent areas of cornea covered by NV. Anti-vascular endothelial growth factor (VEGF) and anti-active caspase-3 immunostainings were also performed in corneal sections. The median percent area of corneal NV was 59% (40.3-65.6) in Group I, 25.5% (20.9-43.4) in Group II, 68.9% (36.7-78.0) in Group III, and 50.4% (42.2-63.3) in Group IV. Group III and IV did not show any difference in comparison to Group I. Group II showed a statistically significant smaller area of corneal NV compared with Group I, III, and IV (P=0.004 for each comparison). Anti-VEGF immunostaining was significantly less in Group II compared with the other groups. Anti-active caspase-3 immunostaining was not different among the treatment groups. Topical propranolol 1 or 0.5 mg/mL does not have a significant inhibitory effect on alkali-induced corneal NV in rats.

  16. Blockade of interleukin-6 receptor suppresses the proliferation of H460 lung cancer stem cells.

    PubMed

    Yi, Hee; Cho, Hee-Jung; Cho, Soo-Min; Jo, Kyul; Park, Jin-A; Kim, Na-Hyun; Amidon, Gordon L; Kim, Jin-Suk; Shin, Ho-Chul

    2012-07-01

    IL-6/6R signaling is closely associated with tumor growth and poor prognosis. Although there is evidence that interleukin-6 receptor (IL-6R)-mediated signaling promotes the growth and malignancy of cancer, the role of IL-6R in cancer stem cells (CSCs) is poorly defined. This study investigated the role of IL-6R in the proliferation of CSCs. Sphere-forming cells were isolated from the H460 non-small cell lung cancer (NSCLC) cell line and identified as CSCs using confocal microscopy, RT-PCR and WST-1 assay. The H460 spheres demonstrated the typical characteristics of CSCs, including CD133 expression, upregulation of Nanog, self-renewal, and drug resistance to methotrexate (MTX) and fluorouracil (5-FU). The release of IL-6R and its ligand, IL-6, were quantitatively determined and compared between CSCs and non-CSCs. The concentration of soluble IL-6R (sIL-6R) was remarkably high in CSCs compared to that in non-CSCs. Furthermore, significant upregulation of the IL-6R gene was also observed in the CSCs. The growth of CSCs was significantly inhibited by transfection with IL-6R small-interfering RNA (siRNA), as well as with the IL-6R monoclonal antibody (mAb). In addition, blocking both IL-6R and IL-6 using siRNA or mAbs intensified the inhibition of CSC proliferation. These findings indicate that IL-6R is present in CSCs and has an important role in the proliferation of CSCs in the H460 lung cancer cell line. Therefore, we suggest that IL-6R is both a viable target for the development of CSC-directed lung cancer therapeutics and a potential CSC marker in NSCLC.

  17. Androgen receptor splice variants circumvent AR blockade by microtubule-targeting agents

    PubMed Central

    Zhang, Guanyi; Liu, Xichun; Li, Jianzhuo; Ledet, Elisa; Alvarez, Xavier; Qi, Yanfeng; Fu, Xueqi; Sartor, Oliver; Dong, Yan; Zhang, Haitao

    2015-01-01

    Docetaxel-based chemotherapy is established as a first-line treatment and standard of care for patients with metastatic castration-resistant prostate cancer. However, half of the patients do not respond to treatment and those do respond eventually become refractory. A better understanding of the resistance mechanisms to taxane chemotherapy is both urgent and clinical significant, as taxanes (docetaxel and cabazitaxel) are being used in various clinical settings. Sustained signaling through the androgen receptor (AR) has been established as a hallmark of CRPC. Recently, splicing variants of AR (AR-Vs) that lack the ligand-binding domain (LBD) have been identified. These variants are constitutively active and drive prostate cancer growth in a castration-resistant manner. In taxane-resistant cell lines, we found the expression of a major variant, AR-V7, was upregulated. Furthermore, ectopic expression of two clinically relevant AR-Vs (AR-V7 and ARV567es), but not the full-length AR (AR-FL), reduced the sensitivities to taxanes in LNCaP cells. Treatment with taxanes inhibited the transcriptional activity of AR-FL, but not those of AR-Vs. This could be explained, at least in part, due to the inability of taxanes to block the nuclear translocation of AR-Vs. Through a series of deletion constructs, the microtubule-binding activity was mapped to the LBD of AR. Finally, taxane-induced cytoplasm sequestration of AR-FL was alleviated when AR-Vs were present. These findings provide evidence that constitutively active AR-Vs maintain the AR signaling axis by evading the inhibitory effects of microtubule-targeting agents, suggesting that these AR-Vs play a role in resistance to taxane chemotherapy. PMID:26160840

  18. Maslinic acid ameliorates NMDA receptor blockade-induced schizophrenia-like behaviors in mice.

    PubMed

    Jeon, Se Jin; Kim, Eunji; Lee, Jin Su; Oh, Hee Kyong; Zhang, Jiabao; Kwon, Yubeen; Jang, Dae Sik; Ryu, Jong Hoon

    2017-09-09

    Schizophrenia is a chronic psychotic disorder characterized by positive, negative, and cognitive symptoms. Primary treatments for schizophrenia relieve the positive symptoms but are less effective against the negative and cognitive symptoms. In the present study, we investigated whether maslinic acid, isolated from Syzygium aromaticum (clove), can ameliorate schizophrenia-like behaviors in mice induced by MK-801, an N-methyl-d-aspartate (NMDA) receptor antagonist. After maslinic acid treatment in the MK-801 model, we examined the behavioral alteration and signaling pathways in the prefrontal cortex. Mice were treated with maslinic acid (30 mg/kg), and their behaviors were evaluated through an array of behavioral tests. The effects of maslinic acid were also examined in the signaling pathways in the prefrontal cortex. A single administration of maslinic acid blocked the MK-801-induced hyperlocomotion and reversed the MK-801-induced sensorimotor gating deficit in the acoustic startle response test. In the social novelty preference test, maslinic acid ameliorated the social behavior deficits induced by MK-801. The MK-801-induced attention and recognition memory impairments were also alleviated by a single administration of maslinic acid. Furthermore, maslinic acid normalized the phosphorylation levels of Akt-GSK-3β and ERK-CREB in the prefrontal cortex. Overall, maslinic acid ameliorated the schizophrenia-like symptoms induced by MK-801, and these effects may be partly mediated through Akt-GSK-3β and ERK-CREB activation. These findings suggest that maslinic acid could be a candidate for the treatment of several symptoms of schizophrenia, including positive symptoms, sensorimotor gating disruption, social interaction deficits, and cognitive impairments. Copyright © 2017. Published by Elsevier Ltd.

  19. Targeted leptin receptor blockade: role of ventral tegmental area and nucleus of the solitary tract leptin receptors in body weight homeostasis.

    PubMed

    Matheny, M; Strehler, K Y E; King, M; Tümer, N; Scarpace, P J

    2014-07-01

    The present investigation examined whether leptin stimulation of ventral tegmental area (VTA) or nucleus of the solitary tract (NTS) has a role in body weight homeostasis independent of the medial basal hypothalamus (MBH). To this end, recombinant adeno-associated viral techniques were employed to target leptin overexpression or overexpression of a dominant negative leptin mutant (leptin antagonist). Leptin antagonist overexpression in MBH or VTA increased food intake and body weight to similar extents over 14 days in rats. Simultaneous overexpression of leptin in VTA with antagonist in MBH resulted in food intake and body weight gain that were less than with control treatment but greater than with leptin alone in VTA. Notably, leptin overexpression in VTA increased P-STAT3 in MBH along with VTA, and leptin antagonist overexpression in the VTA partially attenuated P-STAT3 levels in MBH. Interestingly, leptin antagonist overexpression elevated body weight gain, but leptin overexpression in the NTS failed to modulate either food intake or body weight despite increased P-STAT3. These data suggest that leptin function in the VTA participates in the chronic regulation of food consumption and body weight in response to stimulation or blockade of VTA leptin receptors. Moreover, one component of VTA-leptin action appears to be independent of the MBH, and another component appears to be related to leptin receptor-mediated P-STAT3 activation in the MBH. Finally, leptin receptors in the NTS are necessary for normal energy homeostasis, but mostly they appear to have a permissive role. Direct leptin activation of NTS slightly increases UCP1 levels, but has little effect on food consumption or body weight.

  20. Selective blockade of central m1 muscarinic cholinergic receptors with pirenzepine impairs cardiovascular and respiratory function in rats with acute hemorrhage.

    PubMed

    Kovalenko, N Ya; Matsievskii, D D

    2006-09-01

    Ultrasound studies showed that selective antagonist of central M1 muscarinic cholinergic receptors pirenzepine (50 mg/kg intravenously) causes transitory hypotension and respiratory depression in anesthetized intact rats. The M1 receptor antagonist had no effect on cardiac output and portal blood flow. Pretreatment with pirenzepine increased the sensitivity of rats with acute massive hemorrhage to circulatory hypoxia. After blockade of central M1 muscarinic cholinergic receptors, the posthemorrhagic period was characterized by primary decompensation of blood pressure, portal blood flow, and respiration and development of low cardiac output syndrome. The animals died over the first minutes after bleeding arrest. Our results indicate that central M1 muscarinic cholinergic receptors act as shock-limiting cholinergic structures under conditions of posthemorrhagic changes in systemic and portal blood flow, as well as during respiratory dysfunction.

  1. Pharmacological blockade of either cannabinoid CB1 or CB2 receptors prevents both cocaine-induced conditioned locomotion and cocaine-induced reduction of cell proliferation in the hippocampus of adult male rat

    PubMed Central

    Blanco-Calvo, Eduardo; Rivera, Patricia; Arrabal, Sergio; Vargas, Antonio; Pavón, Francisco Javier; Serrano, Antonia; Castilla-Ortega, Estela; Galeano, Pablo; Rubio, Leticia; Suárez, Juan; Rodriguez de Fonseca, Fernando

    2014-01-01

    Addiction to major drugs of abuse, such as cocaine, has recently been linked to alterations in adult neurogenesis in the hippocampus. The endogenous cannabinoid system modulates this proliferative response as demonstrated by the finding that pharmacological activation/blockade of cannabinoid CB1 and CB2 receptors not only modulates neurogenesis but also modulates cell death in the brain. In the present study, we evaluated whether the endogenous cannabinoid system affects cocaine-induced alterations in cell proliferation. To this end, we examined whether pharmacological blockade of either CB1 (Rimonabant, 3 mg/kg) or CB2 receptors (AM630, 3 mg/kg) would affect cell proliferation [the cells were labeled with 5-bromo-2′-deoxyuridine (BrdU)] in the subventricular zone (SVZ) of the lateral ventricle and the dentate subgranular zone (SGZ). Additionally, we measured cell apoptosis (as monitored by the expression of cleaved caspase-3) and glial activation [by analyzing the expression of glial fibrillary acidic protein (GFAP) and Iba-1] in the striatum and hippocampus during acute and repeated (4 days) cocaine administration (20 mg/kg). The results showed that acute cocaine exposure decreased the number of BrdU-immunoreactive (ir) cells in the SVZ and SGZ. In contrast, repeated cocaine exposure reduced the number of BrdU-ir cells only in the SVZ. Both acute and repeated cocaine exposure increased the number of cleaved caspase-3-, GFAP- and Iba1-ir cells in the hippocampus, and this effect was counteracted by AM630 or Rimonabant, which increased the number of BrdU-, GFAP-, and Iba1-ir cells in the hippocampus. These results indicate that the changes in neurogenic, apoptotic and gliotic processes that were produced by repeated cocaine administration were normalized by pharmacological blockade of CB1 and CB2. The restorative effects of cannabinoid receptor blockade on hippocampal cell proliferation were associated with the prevention of the induction of conditioned

  2. Vascular endothelial growth factor blockade alters magnetic resonance imaging biomarkers of vascular function and decreases barrier permeability in a rat model of lung cancer brain metastasis.

    PubMed

    Pishko, Gregory L; Muldoon, Leslie L; Pagel, Michael A; Schwartz, Daniel L; Neuwelt, Edward A

    2015-02-17

    Blockade of vascular endothelial growth factor (VEGF) to promote vascular normalization and inhibit angiogenesis has been proposed for the treatment of brain metastases; however, vascular normalization has not been well-characterized in this disease. We investigated the effect of treatment with bevacizumab anti-VEGF antibody on magnetic resonance imaging (MRI) biomarkers of brain tumor vascular characteristics in comparison to small molecule delivery in a rat model of human lung cancer brain metastasis. Athymic rats with A549 human lung adenocarcinoma intracerebral xenografts underwent MRI at 11.75 T before and one day after treatment with bevacizumab (n = 8) or saline control (n = 8) to evaluate tumor volume, free water content (edema), blood volume and vascular permeability (Ktrans). One day later, permeability to 14C-aminoisobutyric acid (AIB) was measured in tumor and brain to assess the penetration of a small drug-like molecule. In saline control animals, tumor volume, edema and permeability increased over the two day assessment period. Compared to controls, bevacizumab treatment slowed the rate of tumor growth (P = 0.003) and blocked the increase in edema (P = 0.033), but did not alter tumor blood volume. Bevacizumab also significantly reduced Ktrans (P = 0.033) and AIB passive permeability in tumor (P = 0.04), but not to peritumoral tissue or normal brain. Post-treatment Ktrans correlated with AIB levels in the bevacizumab-treated rats but not in the saline controls. The correlation of an MRI biomarker for decreased vascular permeability with decreased AIB concentration in tumor after antiangiogenic treatment suggests that bevacizumab partially restored the normal low permeability characteristics of the blood-brain barrier in a model of human lung cancer brain metastasis.

  3. Dietary peptides from the non-digestible fraction of Phaseolus vulgaris L. decrease angiotensin II-dependent proliferation in HCT116 human colorectal cancer cells through the blockade of the renin-angiotensin system.

    PubMed

    Luna-Vital, Diego A; Liang, Katie; González de Mejía, Elvira; Loarca-Piña, Guadalupe

    2016-05-18

    This study aimed to determine the ability of peptides present in the non-digestible fraction (NDF) of common beans to decrease angiotensin II (AngII) through the blockade of RAS and its effect on the proliferation of HCT116 human colorectal cancer cells. Pure synthesized peptides GLTSK and GEGSGA and the peptide fractions (PF) of cultivars Azufrado Higuera and Bayo Madero were used. The cells were pretreated with pure peptides, PF or AGT at their IC50 or IC25 values, in comparison with the simultaneous treatment of peptides and AGT. For western blot and microscopy analysis, 100 μM and 0.5 mg mL(-1) were used for pure peptides and PF treatments, respectively. According to the ELISA tests, GLTSK and GEGSGA decreased (p < 0.05) the conversion rate of AGT to angiotensin I (AngI) by 38 and 28%, respectively. All the peptides tested reduced (p < 0.05) the conversion rate of AngI to AngII from 38 to 50%. When the cells were pretreated with both pure peptides and PF before exposure to AGT, the effectiveness inhibiting cell proliferation was higher than the simultaneous treatment suggesting their preventive effects. GLTSK and GEGSGA interacted with the catalytic site of renin, the angiotensin-I converting enzyme, and the AngII receptor, mainly through hydrogen bonds, polar, hydrophobic and cation-π interactions according to molecular docking. Through confocal microscopy, it was determined that GLTSK and GEGSGA caused the decrease (p < 0.05) of AngII-dependent STAT3 nuclear activation in HCT116 cells by 66 and 23%, respectively. The results suggest that peptides present in the common bean NDF could potentially ameliorate the effects of RAS overexpression in colorectal cancer.

  4. Decreased autophosphorylation of EGF receptor in insulin-deficient diabetic rats

    SciTech Connect

    Okamoto, M.; Kahn, C.R.; Maron, R.; White, M.F. )

    1988-04-01

    The authors have previously reported that despite an increase in receptor concentration, there is a decrease in autophosphorylation and tyrosine kinase activity of the insulin receptor in insulin-deficient diabetic rats. To determine if other tyrosine kinases might be altered, they have studied the epidermal growth factor (EGF) receptor kinase in wheat germ agglutinin-purified, Triton X-100-solubilized liver membranes from streptozotocin (STZ)-induced diabetic rats and the insulin-deficient BB rat. They find that autophosphorylation of EGF receptor is decreased in proportion to the severity of the diabetic state in STZ rats with a maximal decrease of 67%. A similar decrease in autophosphorylation was observed in diabetic BB rats that was partially normalized by insulin treatment. Separation of tryptic phosphopeptides by reverse-phase high-performance liquid chromatography revealed a decrease in labeling at all sites of autophosphorylation. A parallel decrease in EGF receptor phosphorylation was also found by immunoblotting with an antiphosphotyrosine antibody. EGF receptor concentration, determined by Scatchard analysis of {sup 125}I-labeled EGF binding, was decreased by 39% in the STZ rat and 27% in the diabetic BB rat. Thus autophosphorylation of EGF receptor, like that of the insulin receptor, is decreased in insulin-deficient rat liver. In the case of EGF receptor, this is due in part to a decrease in receptor number and in part to a decrease in the specific activity of the kinase.

  5. Blockade of Glucagon-like Peptide 1 Receptor Corrects Post-prandial Hypoglycemia After Gastric Bypass

    PubMed Central

    Salehi, Marzieh; Gastaldelli, Amalia; D'Alessio, David A.

    2014-01-01

    Background & Aims Post-prandial glycemia excursions increase after gastric bypass surgery; this effect is even greater among individuals with recurrent hypoglycemia (blood glucose levels <50 mg/dL). These patients also have increased post-prandial levels of insulin and glucagon-like peptide 1 (GLP1). We performed a clinical trial to determine the role of GLP1 in post-prandial glycemia in patients with hyperinsulinemic hypoglycemia syndrome after gastric bypass. Methods Nine patients with recurrent hypoglycemia after gastric bypass (H-GB), 7 asymptomatic individuals with previous gastric bypass (A-GB), and 8 non-diabetic subjects who did not receive surgery (controls) were studied with a mixed-meal tolerance test (350 kcal) using a dual glucose tracer method on 2 days. On 1 day they received continuous infusion of GLP-1 receptor (GLP1R) antagonist, exendin-(9–39) (Ex-9), and on the other day, a saline control. Glucose kinetics and islet and gut hormone responses were measured before and after the meal. Results Infusion of Ex9 corrected hypoglycemia in all H-GB individuals. The reduction of post-prandial insulin secretion by Ex9 was greater in the H-GB group than other groups (H-GB, 50%±8%; A-GB, 13%±10%; and controls, 14%±10%) (P<.05). Meal-derived glucose (RaOral) was significantly greater among subjects who had undergone gastric bypass than controls, and in H-GB patients compared with A-GB subjects. Ex9 shortened the time to peak RaOral in all groups without any significant effect on the overall glucose flux. Post-prandial glucagon levels were higher among patients who had undergone gastric bypass than controls, and increased with Ex9 administration. Conclusions Hypoglycemia following gastric bypass can be corrected by administration of a GLP1R antagonist, which might be used to treat this disorder. These findings are consistent with reports that increased GLP1 activity contributes to hypoglycemia following gastric bypass. ClinicalTrials.gov number, NCT

  6. NMDA receptor blockade by ketamine abrogates lipopolysaccharide-induced depressive-like behavior in C57BL/6J mice.

    PubMed

    Walker, Adam K; Budac, David P; Bisulco, Stephanie; Lee, Anna W; Smith, Robin A; Beenders, Brent; Kelley, Keith W; Dantzer, Robert

    2013-08-01

    We have previously demonstrated that lipopolysaccharide (LPS) induces depressive-like behavior by activating indoleamine 2,3 dioxygenase (IDO; O'Connor et al, 2009c). IDO degrades tryptophan along the kynurenine pathway. Using mass-spectrometry (LC-MS) analysis of kynurenine metabolites in the brain of mice injected at the periphery with 1 mg/kg LPS, we show that LPS activates the kynurenine 3-monooxygenase pathway that ultimately degrades kynurenine into quinolinic acid. As quinolinic acid acts as an N-methyl-D-aspartate (NMDA) receptor agonist, we used the NMDA receptor antagonist ketamine to assess the role of NMDA receptor activation in LPS-induced depressive-like behavior. Here, we report that a low dose of ketamine (6 mg/kg, intraperitoneally) immediately before administration of LPS (0.83 mg/kg, intraperitoneally) in C57Bl/6 J mice abrogated the development of LPS-induced depressive-like behavior, without altering LPS-induced sickness measured by body weight loss, decreased motor activity, and reduced food intake. Depressive-like behavior was measured 24 h after LPS by decreased sucrose preference and increased immobility in the forced swim test (FST). Ketamine had no effect on LPS-induced cytokine expression in the liver and brain, IDO activation, and brain-derived neurotrophic factor (BDNF) transcripts. The ability of ketamine to abrogate LPS-induced depressive-like behavior independently of a possible interference with LPS-induced inflammatory signaling was confirmed when ketamine was administered 10 h after LPS instead of immediately before LPS. In contrast, ketamine had no effect when administered 24 h before LPS. To confirm that NMDA receptor antagonism by ketamine mediates the antidepressant-like activity of this compound in LPS-treated mice, mice were pretreated with the α-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA) receptor antagonist 2,3-dihydroxy-6-nitro-7-sulfamoyl-benzo(f)quinoxaline-2,3-dione (NBQX) to block enhanced AMPA

  7. Effect of androgen suppression compared with androgen receptor blockade on arterial stiffness in men with prostate cancer.

    PubMed

    Dockery, Frances; Bulpitt, Christopher J; Agarwal, Sanjiv; Vernon, Clare; Rajkumar, Chakravarthi

    2009-01-01

    Endogenous testosterone and estradiol are thought to be cardio-protective in men. We wanted to determine the effects of 2 different anti-androgen therapies on arterial stiffness as one suppresses (goserelin--a gonadotrophin-releasing hormone analog) while the other increases (bicalutamide--an androgen receptor blocker) both testosterone and estradiol. We conducted a randomized trial on 43 men (mean age, 71.2 +/- 6.2 years) with localized prostate cancer. They received either goserelin or bicalutamide for 24 weeks. Carotid-femoral (C-F) and carotid-radial (C-R) pulse wave velocities (PWVs) were measured. Twenty age- and disease-matched men with prostate cancer on no active treatment were studied in a similar manner. After 12 weeks of goserelin, radial artery PWV increased significantly from baseline and a nonsignificant increase was observed in femoral PWV (change from baseline radial: +1.4 m/s, P = .002, femoral: +0.9 m/s, P = .127) Both PWV measures increased significantly with bicalutamide (change from baseline radial: +0.8, femoral: +0.9 m/s, P or= .967 at 12 weeks and P >or= .07 at 24 weeks). The untreated men studied in parallel showed no changes at 12 or 24 weeks in either PWV measure. Anti-androgen treatment in men might increase large artery stiffness, an adverse cardiovascular risk factor; however, the effect was not maintained with testosterone receptor blockade, in the longer term, but tended to be sustained with suppression therapy. This could relate to the different sex hormone effects of the 2 therapies.

  8. Blockade of beta 1- but not of beta 2-adrenergic receptors replicates propranolol's suppression of the cerebral spread of an engram in mice.

    PubMed Central

    Flexner, J B; Flexner, L B; Church, A C; Rainbow, T C; Brunswick, D J

    1985-01-01

    Bitemporal injections of puromycin that primarily affect the hippocampal-entorhinal area induce amnesia of aversive maze-learning in mice for 3 days after training but are ineffective 6 or more days after training. At these later times, additional puromycin sites covering widespread forebrain areas are necessary to induce amnesia, a result that we attribute to the cerebral spread of the engram during the 6-day period. We have reported that blockade of about 60% of cerebral beta-adrenergic receptors by a single, subcutaneous injection of (-)-propranolol, a nonselective beta-receptor antagonist, inhibited engram spread for 60-90 days, at which time engram spread spontaneously occurred. In the present experiments using single doses of antagonists that appeared to block 60% of beta 2- or beta 1-adrenergic receptors, it was found that the selective beta 2 antagonist ICI 118,551 was without effect on engram spread, whereas the selective beta 1 antagonist betaxolol inhibited the spread for at least 3 months. Propranolol's effect consequently appears to be accounted for by its blockade of beta 1 receptors. PMID:2865730

  9. The effect of dopamine receptor blockade in the rodent nucleus accumbens on local field potential oscillations and motor activity in response to ketamine.

    PubMed

    Matulewicz, Pawel; Kasicki, Stefan; Hunt, Mark Jeremy

    2010-12-17

    Altered functioning of the nucleus accumbens (NAc) has been implicated in the psychotomimetic actions of NMDA receptor (NMDAR) antagonists and the pathophysiology of schizophrenia. We have shown previously that NMDAR antagonists enhance the power of high-frequency oscillations (HFO) in the NAc in a dose-dependent manner, as well as increase locomotor activity. Systemic administration of NMDAR antagonists is known to increase the release of dopamine in the NAc and dopamine antagonists can reduce ketamine-induced hyperactivity. In this study, we examined the effect of 0.5 μl intra-NAc infusion of 3.2 μg SCH23390 (D1 antagonist), 10 μg raclopride (D2 antagonist) and saline on ketamine-induced changes in motor and oscillatory activity. We found that local blockade of D1 receptors attenuated ketamine-induced increases in motor activity and blockade of D2 receptors produced a much weaker effect, with respect to saline-infused control groups. In contrast, none of the antagonists, infused separately or together, significantly modified the power or dominant frequency of ketamine-induced increases in HFO, but changes in delta and theta frequency bands were observed. Together, these findings suggest, that, in contrast to delta and theta frequency bands, the generation of ketamine enhanced-HFO in the NAc is not causally related to locomotor activation and occurs largely independently of local changes in dopamine receptor activation. Copyright © 2010 Elsevier B.V. All rights reserved.

  10. Synergistic interaction between opioid receptor blockade and alpha-adrenergic stimulation on luteinizing hormone-releasing hormone (LHRH) secretion in vitro.

    PubMed

    Clough, R W; Hoffman, G E; Sladek, C D

    1990-02-01

    The effects of opioid receptor blockade, alpha-adrenergic receptor stimulation and concomitant opioid blockade and adrenergic stimulation on LHRH neurosecretion was examined in tissue culture using perifused preoptic area-mediobasal hypothalamic (POA-MBH) explants. Blockade of opioid receptors using naloxone (NAL) resulted in increased (p less than 0.05) LHRH secretion from POA-MBH explants obtained from intact postpubertal female rats. After washout of the NAL-medium, basal release rate was reset to a lower baseline. Subsequent exposure of POA-MBH explants to phenylephrine (PHEN), an alpha-adrenergic agonist, resulted in a slight but statistically insignificant increase in LHRH release from adult explants. The attenuated response to PHEN may have been due to a sustained inhibition of LHRH release following the NAL exposure since PHEN not preceded by NAL resulted in a marked stimulation of LHRH release. In three separate experiments, the LHRH response in postpubertal rat explants to simultaneous PHEN and NAL was greater and more prolonged than the responses to either of the substances alone. This study demonstrates that the stimulatory effects of PHEN are much more profound in the presence of opioid receptor blockage. The observations of the stimulatory effects of PHEN and NAL potentiating each other also suggest that separate mechanisms of LHRH control by each class of neurotransmitter are present. Similar to the postpubertal rat explants, explants obtained from prepubertal rats increased LHRH release in response to NAL and showed a sustained inhibition of LHRH release following washout of NAL. Explants obtained from prepubertal rats also significantly increased LHRH release in response to PHEN.(ABSTRACT TRUNCATED AT 250 WORDS)

  11. Correction of abnormal B-cell subset distribution by interleukin-6 receptor blockade in polymyalgia rheumatica.

    PubMed

    Carvajal Alegria, Guillermo; Devauchelle-Pensec, Valérie; Renaudineau, Yves; Saraux, Alain; Pers, Jacques-Olivier; Cornec, Divi

    2017-08-01

    The aim was to study lymphocyte subsets and circulating cytokines at diagnosis of PMR and after tocilizumab monotherapy. Eighteen untreated patients with PMR were included in a prospective study and received 3-monthly tocilizumab infusions without glucocorticoids. Lymphocyte subset distribution was assessed by flow cytometry and serum cytokines were assayed by a 34-cytokine array and ELISA, at baseline and during follow-up. Baseline data were also compared with age- and sex-matched controls. At baseline, total lymphocytes, T-cell subsets and NK cell counts were similar in patients and controls, but patients had significantly lower B-cell counts attributable to lower transitional, naïve and post-switch memory B-cell subsets. Circulating B-cell counts were positively correlated with the PMR activity score (PMR-AS) in untreated active patients at baseline, but subsequently increased to normal values while disease activity was controlled after tocilizumab therapy. Among serum cytokines, IL-6 showed the largest concentration difference between patients and controls, and the serum IL-6 concentration was correlated with baseline PMR-AS. The effects of tocilizumab on serum IL-6 concentration were heterogeneous, and the patients whose serum IL-6 decreased after tocilizumab therapy exhibited a significant increase in circulating B-cell counts. In patients with PMR, B-cell lymphopenia and abnormal B-cell subset distribution are associated with disease activity and IL-6 concentration, and both are corrected by the IL-6 antagonist tocilizumab.

  12. Decrease of Obesity by Allantoin via Imidazoline I1-Receptor Activation in High Fat Diet-Fed Mice

    PubMed Central

    Chung, Hsien-Hui; Lee, Kung Shing

    2013-01-01

    The activation of the imidazoline I1-receptor (I1R) is known to regulate appetite. Allantoin, an active ingredient in the yam, has been reported to improve lipid metabolism in high fat diet- (HFD-)fed mice. However, the effect of allantoin on obesity remains unclear. In the present study, we investigated the effects of allantoin on HFD-induced obesity. The chronic administration of allantoin to HFD-fed mice for 8 weeks significantly decreased their body weight, and this effect was reversed by efaroxan at a dose sufficient to block I1R. The epididymal white adipose tissue (eWAT) cell size and weight in HFD-fed mice were also decreased by allantoin via the activation of I1R. In addition, allantoin significantly decreased the energy intake of HFD-fed mice, and this reduction was associated with a decrease in the NPY levels in the brain. However, no inhibitory effect of allantoin on energy intake was observed in db/db mice. Moreover, allantoin lowered HFD-induced hyperleptinemia, and this activity was abolished by I1R blockade with efaroxan. Taken together, these data suggest that allantoin can ameliorate energy intake and eWAT accumulation by activating I1R to improve HFD-induced obesity. PMID:23606885

  13. Mitochondrial activation chemicals synergize with surface receptor PD-1 blockade for T cell-dependent antitumor activity.

    PubMed

    Chamoto, Kenji; Chowdhury, Partha S; Kumar, Alok; Sonomura, Kazuhiro; Matsuda, Fumihiko; Fagarasan, Sidonia; Honjo, Tasuku

    2017-01-31

    Although immunotherapy by PD-1 blockade has dramatically improved the survival rate of cancer patients, further improvement in efficacy is required to reduce the fraction of less sensitive patients. In mouse models of PD-1 blockade therapy, we found that tumor-reactive cytotoxic T lymphocytes (CTLs) in draining lymph nodes (DLNs) carry increased mitochondrial mass and more reactive oxygen species (ROS). We show that ROS generation by ROS precursors or indirectly by mitochondrial uncouplers synergized the tumoricidal activity of PD-1 blockade by expansion of effector/memory CTLs in DLNs and within the tumor. These CTLs carry not only the activation of mechanistic target of rapamycin (mTOR) and AMP-activated protein kinase (AMPK) but also an increment of their downstream transcription factors such as PPAR-gamma coactivator 1α (PGC-1α) and T-bet. Furthermore, direct activators of mTOR, AMPK, or PGC-1α also synergized the PD-1 blockade therapy whereas none of above-mentioned chemicals alone had any effects on tumor growth. These findings will pave a way to developing novel combinatorial therapies with PD-1 blockade.

  14. Mitochondrial activation chemicals synergize with surface receptor PD-1 blockade for T cell-dependent antitumor activity

    PubMed Central

    Chamoto, Kenji; Chowdhury, Partha S.; Kumar, Alok; Sonomura, Kazuhiro; Matsuda, Fumihiko; Fagarasan, Sidonia; Honjo, Tasuku

    2017-01-01

    Although immunotherapy by PD-1 blockade has dramatically improved the survival rate of cancer patients, further improvement in efficacy is required to reduce the fraction of less sensitive patients. In mouse models of PD-1 blockade therapy, we found that tumor-reactive cytotoxic T lymphocytes (CTLs) in draining lymph nodes (DLNs) carry increased mitochondrial mass and more reactive oxygen species (ROS). We show that ROS generation by ROS precursors or indirectly by mitochondrial uncouplers synergized the tumoricidal activity of PD-1 blockade by expansion of effector/memory CTLs in DLNs and within the tumor. These CTLs carry not only the activation of mechanistic target of rapamycin (mTOR) and AMP-activated protein kinase (AMPK) but also an increment of their downstream transcription factors such as PPAR-gamma coactivator 1α (PGC-1α) and T-bet. Furthermore, direct activators of mTOR, AMPK, or PGC-1α also synergized the PD-1 blockade therapy whereas none of above-mentioned chemicals alone had any effects on tumor growth. These findings will pave a way to developing novel combinatorial therapies with PD-1 blockade. PMID:28096382

  15. Beneficial Effects of Combined AT1 Receptor/Neprilysin Inhibition (ARNI) Versus AT1 Receptor Blockade Alone in the Diabetic Eye

    PubMed Central

    Prasad, Tuhina; Roksnoer, Lodi C. W.; Zhu, Ping; Verma, Amrisha; Li, Yiming; Batenburg, Wendy W.; de Vries, René; Danser, A. H. Jan; Li, Qiuhong

    2016-01-01

    Purpose Dysfunction of the renin-angiotensin system (RAS) contributes to pathogenesis of diabetic retinopathy (DR). Yet RAS blockers have only limited beneficial effects on progression of DR in clinical trials. The natriuretic peptide system offsets RAS, so that enhancing the activity of this system on top of RAS blockade might be beneficial. Neprilysin has an important role in the degradation of natriuretic peptides. Therefore, we hypothesize that dual angiotensin receptor-neprilysin inhibition (ARNI) may outperform angiotensin receptor blocker (ARB) in protection against DR. We tested this hypothesis in streptozotocin-induced diabetic transgenic (mRen2)27 rats. Methods Adult male diabetic (mRen2)27 rats were followed for 5 or 12 weeks. Treatment with vehicle, irbesartan (ARB), or ARB combined with the neprilysin inhibitor thiorphan (irbesartan+thiorphan [ARNI]) occurred during the final 3 weeks. Retinal cell death, gliosis, and capillary loss were evaluated. Real-time polymerase chain reaction (RT-PCR) analyses were performed to quantify the retinal level of inflammatory cell markers. Results Both ARB- and ARNI-treated groups showed similarly reduced retinal apoptotic cell death, gliosis, and capillary loss compared to the vehicle-treated group in the 5-week study. Treatment with ARNI reduced the expression of inflammatory markers more than ARB treatment in the 5-week study. In the 12-week study, ARNI treatment showed significantly more reduction in apoptotic cell death (51% vs. 25% reduction), and capillary loss (68% vs. 43% reduction) than ARB treatment. Conclusions Treatment with ARNI provides better protection against DR in diabetic (mRen2)27 transgenic rats, compared to ARB alone. This approach may be a promising treatment option for patients with DR. PMID:27951594

  16. Recovery from ketamine-induced amnesia by blockade of GABA-A receptor in the medial prefrontal cortex of mice.

    PubMed

    Farahmandfar, Maryam; Akbarabadi, Ardeshir; Bakhtazad, Atefeh; Zarrindast, Mohammad-Reza

    2017-03-06

    Ketamine and other noncompetitive N-methyl-d-aspartate (NMDA) receptor antagonists are known to induce deficits in learning and cognitive performance sensitive to prefrontal cortex (PFC) functions. The interaction of a glutamatergic and GABAergic systems is essential for many cognitive behaviors. In order to understand the effect of γ-aminobutyric acid (GABA)/glutamate interactions on learning and memory, we investigated the effects of intra medial prefrontal cortex (mPFC) injections of GABAergic agents on ketamine-induced amnesia using a one-trial passive avoidance task in mice. Pre-training systemic administration of ketamine (5, 10 and 15mg/kg, i.p.) dose-dependently decreased the memory acquisition of a one-trial passive avoidance task. Pre-training intra-mPFC injection of muscimol, GABAA receptor agonist (0.05, 0.1 and 0.2μg/mouse) and baclofen GABAB receptor agonist (0.05, 0.1, 0.5 and 1μg/mouse), impaired memory acquisition. However, co-pretreatment of different doses of muscimol and baclofen with a lower dose of ketamine (5mg/kg), which did not induce amnesia by itself, caused inhibition of memory formation. Our data showed that sole pre-training administration of bicuculline, GABA-A receptor antagonist and phaclofen GABA-B receptor antagonist into the mPFC, did not affect memory acquisition. In addition, the amnesia induced by pre-training ketamine (15mg/kg) was significantly decreased by the pretreatment of bicuculline (0.005, 0.1 and 0.5μg/mouse). It can be concluded that GABAergic system of the mPFC is involved in the ketamine-induced impairment of memory acquisition.

  17. Lymphotoxin-beta receptor blockade reduces CXCL13 in lacrimal glands and improves corneal integrity in the NOD model of Sjögren's syndrome

    PubMed Central

    2011-01-01

    Introduction In Sjögren's syndrome, keratoconjunctivitis sicca (dry eye) is associated with infiltration of lacrimal glands by leukocytes and consequent losses of tear-fluid production and the integrity of the ocular surface. We investigated the effect of blockade of the lymphotoxin-beta receptor (LTBR) pathway on lacrimal-gland pathology in the NOD mouse model of Sjögren's syndrome. Methods Male NOD mice were treated for up to ten weeks with an antagonist, LTBR-Ig, or control mouse antibody MOPC-21. Extra-orbital lacrimal glands were analyzed by immunohistochemistry for high endothelial venules (HEV), by Affymetrix gene-array analysis and real-time PCR for differential gene expression, and by ELISA for CXCL13 protein. Leukocytes from lacrimal glands were analyzed by flow-cytometry. Tear-fluid secretion-rates were measured and the integrity of the ocular surface was scored using slit-lamp microscopy and fluorescein isothiocyanate (FITC) staining. The chemokine CXCL13 was measured by ELISA in sera from Sjögren's syndrome patients (n = 27) and healthy controls (n = 30). Statistical analysis was by the two-tailed, unpaired T-test, or the Mann-Whitney-test for ocular integrity scores. Results LTBR blockade for eight weeks reduced B-cell accumulation (approximately 5-fold), eliminated HEV in lacrimal glands, and reduced the entry rate of lymphocytes into lacrimal glands. Affymetrix-chip analysis revealed numerous changes in mRNA expression due to LTBR blockade, including reduction of homeostatic chemokine expression. The reduction of CXCL13, CCL21, CCL19 mRNA and the HEV-associated gene GLYCAM-1 was confirmed by PCR analysis. CXCL13 protein increased with disease progression in lacrimal-gland homogenates, but after LTBR blockade for 8 weeks, CXCL13 was reduced approximately 6-fold to 8.4 pg/mg (+/- 2.7) from 51 pg/mg (+/-5.3) in lacrimal glands of 16 week old control mice. Mice given LTBR blockade exhibited an approximately two-fold greater tear-fluid secretion than

  18. Cholinergic receptor blockade by scopolamine and mecamylamine exacerbates global cerebral ischemia induced memory dysfunction in C57BL/6J mice.

    PubMed

    Ray, R S; Rai, S; Katyal, A

    2014-12-01

    Global cerebral ischemia/reperfusion (GCI/R) injury encompasses complex pathophysiological sequalae, inducing loss of hippocampal neurons and behavioural deficits. Progressive neuronal death and memory dysfunctions culminate from several different mechanisms like oxidative stress, excitotoxicity, neuroinflammation and cholinergic hypofunction. Experimental evidences point to the beneficial effects of cholinomimetic agents such as rivastigmine and galantamine in improving memory outcomes following GCI/R injury. However, the direct implications of muscarinic and nicotinic receptor blockade during global cerebral ischemia/reperfusion injury have not been investigated. Therefore, we evaluated the relative involvement of muscarinic and nicotinic receptors in spatial/associative memory functions and neuronal damage during global cerebral ischemia reperfusion injury. The outcomes of present study support the idea that preservation of both muscarinic and nicotinic receptor functions is essential to alleviate hippocampal neuronal death in CA1 region following global cerebral ischemia/reperfusion injury.

  19. Chronic NMDA receptor blockade in early postnatal period, but not in adulthood, impairs methamphetamine-induced conditioned place preference in rats.

    PubMed

    Furuie, Hiroki; Yamada, Kazuo; Ichitani, Yukio

    2016-03-15

    Early postnatal glutamatergic N-methyl-d-aspartate (NMDA) receptor blockade in animals is known to produce various behavioral deficits in adulthood. In the present study rats postnatally (day 7-20) treated chronically with MK-801, an NMDA receptor antagonist, were tested later in adulthood in methamphetamine (MAP)-induced conditioned place preference (CPP) using a unbiased procedure in a three-compartment apparatus. Rats with the same chronic treatment in adulthood were also tested. CPP test consisted of a baseline test before conditioning, place conditioning, and a preference test after conditioning. Rats postnatally treated with MK-801 did not show any evidence of preference for MAP-paired compartment compared with that for unpaired one in the preference test that was shown in rats postnatally treated with saline. On the other hand, rats treated with MK-801 in adulthood were not affected by the treatment and showed significant CPP as was shown in saline-treated control animals. Results suggest the possibility that chronic early postnatal, but not adulthood, NMDA receptor blockade induces persistent deficit of subsequent appetitive classical conditioning. Copyright © 2015 Elsevier B.V. All rights reserved.

  20. Selective blockade and recovery of cell surface alpha 2-adrenergic receptors in human erythroleukemia (HEL) cells. Studies with the irreversible antagonist benextramine

    SciTech Connect

    McKernan, R.M.; Strickland, W.R.; Insel, P.A.

    1988-01-01

    alpha 2-Adrenergic receptors are present on human erythroleukemia (HEL) cells, both on the cell surface and in a sequestered compartment. In the current study we show that benextramine, a hydrophilic irreversible antagonist, can be used to investigate alpha 2-adrenergic receptor compartmentation in these cells. In membranes prepared from HEL cells, benextramine competed for all alpha 2-adrenergic receptors ( (/sup 3/H)yohimbine sites). In intact cells, at 4 degrees, benextramine exhibited a biphasic competition curve for alpha 2-adrenergic receptors, with EC50 values of approximately 10 microM and greater than 1 mM for the high and low affinity components, respectively. We propose that the alpha 2-adrenergic receptors preferentially blocked by benextramine are those on the surface of the cell, whereas those with low affinity are sequestered receptors because: 1) only epinephrine-accessible sites are removed by prior treatment of cells with benextramine, 2) a preparation enriched with surface membranes is also enriched in receptors with a high affinity for benextramine; and 3) after blockade of cell surface receptors (54 +/- 6% of total sites, n = 7) by benextramine, the ability of the alpha 2-adrenergic agonists epinephrine and UK-14,304 to inhibit forskolin-stimulated cAMP accumulation is lost. The latter result implies that only cell surface and not sequestered receptors are functionally coupled to adenylate cyclase. The return of receptors from the sequestered compartment to the cell surface and the recovery of alpha 2-adrenergic receptor function were measured after HEL cells were treated with benextramine (50 microM for 1 hr at 4 degrees). The recovery of receptor binding (t1/2 = 25 min) was somewhat slower than the recovery of function (t1/2 approximately 8 min).

  1. Effects of local alpha2-adrenergic receptor blockade on adipose tissue lipolysis during prolonged systemic adrenaline infusion in normal man.

    PubMed

    Simonsen, Lene; Enevoldsen, Lotte H; Stallknecht, Bente; Bülow, Jens

    2008-03-01

    During prolonged adrenaline infusion, lipolysis peaks within 30 min and thereafter tends to decline, and we hypothesized that the stimulation of local adipose tissue alpha2-adrenergic receptors accounts for this decline. The lipolytic effect of a prolonged intravenous adrenaline infusion combined with local infusion of the alpha2-blocker phentolamine in superficial and deep abdominal subcutaneous adipose tissue and in preperitoneal adipose tissue was studied in seven healthy subjects. The interstitial glycerol concentration in the three adipose tissue depots was measured by the microdialysis method. Regional adipose tissue blood flow was measured by the (133)Xe clearance technique. Regional glycerol output (lipolytic rate) was calculated from these measurements and simultaneous measurements of arterial glycerol concentrations. Adrenaline infusion increased lipolysis in all three depots (data previously published). Phentolamine infusion did not augment lipolysis in the subcutaneous depots while it increased the lipolytic rate in the preperitoneal depot. It is concluded that alpha2-adrenergic receptors do not have a significant effect on subcutaneous adipose tissue lipolysis during high circulating adrenaline concentrations, and the decrease in lipolysis in subcutaneous adipose tissue under prolonged adrenaline stimulation is thus not attributed to alpha2-adrenergic receptor inhibition of lipolysis. However, in the preperitoneal adipose tissue depot, alpha2-adrenergic receptor tone plays a role for the lipolytic rate obtained during prolonged adrenaline stimulation.

  2. Decreased glucocorticoid receptor activity following glucocorticoid receptor antisense RNA gene fragment transfection.

    PubMed Central

    Pepin, M C; Barden, N

    1991-01-01

    Depression is often characterized by increased cortisol secretion caused by hyperactivity of the hypothalamic-pituitary-adrenal axis and by nonsuppression of cortisol secretion following dexamethasone administration. This hyperactivity of the hypothalamic-pituitary-adrenal axis could result from a reduced glucocorticoid receptor (GR) activity in neurons involved in its control. To investigate the effect of reduced neuronal GR levels, we have blocked cellular GR mRNA processing and/or translation by introduction of a complementary GR antisense RNA strand. Two cell lines were transfected with a reporter plasmid carrying the chloramphenicol acetyltransferase (CAT) gene under control of the mouse mammary tumor virus long terminal repeat (a glucocorticoid-inducible promoter). This gene construction permitted assay of the sensitivity of the cells to glucocorticoid hormones. Cells were also cotransfected with a plasmid containing 1,815 bp of GR cDNA inserted in the reverse orientation downstream from either a neurofilament gene promoter element or the Rous sarcoma virus promoter element. Northern (RNA) blot analysis demonstrated formation of GR antisense RNA strands. Measurement of the sensitivity of CAT activity to exogeneous dexamethasone showed that although dexamethasone increased CAT activity by as much as 13-fold in control incubations, expression of GR antisense RNA caused a 2- to 4-fold decrease in the CAT response to dexamethasone. Stable transfectants bearing the GR antisense gene fragment construction demonstrated a 50 to 70% decrease of functional GR levels compared with normal cells, as evidenced by a ligand-binding assay with the type II glucocorticoid receptor-specific ligand [3H]RU 28362. These results validate the use of antisense RNA to GR to decrease cellular response to glucocorticoids. Images PMID:1996114

  3. EGFR-TKI, erlotinib, causes hypomagnesemia, oxidative stress, and cardiac dysfunction: attenuation by NK-1 receptor blockade.

    PubMed

    Mak, I Tong; Kramer, Jay H; Chmielinska, Joanna J; Spurney, Christopher F; Weglicki, William B

    2015-01-01

    To determine whether the epidermal growth factor receptor tyrosine kinase inhibitor, erlotinib may cause hypomagnesemia, inflammation, and cardiac stress, erlotinib was administered to rats (10 mg · kg(-1)· d(-1)) for 9 weeks. Plasma magnesium decreased progressively between 3 and 9 weeks (-9% to -26%). Modest increases in plasma substance P (SP) occurred at 3 (27%) and 9 (25%) weeks. Neutrophil superoxide-generating activity increased 3-fold, and plasma 8-isoprostane rose 210%, along with noticeable appearance of cardiac perivascular nitrotyrosine. The neurokinin-1 (NK-1) receptor antagonist, aprepitant (2 mg · kg(-1) · d(-1)), attenuated erlotinib-induced hypomagnesemia up to 42%, reduced circulating SP, suppressed neutrophil superoxide activity and 8-isoprostane elevations; cardiac nitrotyrosine was diminished. Echocardiography revealed mild to moderately decreased left ventricular ejection fraction (-11%) and % fractional shortening (-17%) by 7 weeks of erlotinib treatment and significant reduction (-17.5%) in mitral valve E/A ratio at week 9 indicative of systolic and early diastolic dysfunction. Mild thinning of the left ventricular posterior wall suggested early dilated cardiomyopathy. Aprepitant completely prevented the erlotinib-induced systolic and diastolic dysfunction and partially attenuated the anatomical changes. Thus, chronic erlotinib treatment does induce moderate hypomagnesemia, triggering SP-mediated oxidative/inflammation stress and mild-to-moderate cardiac dysfunction, which can largely be corrected by the administration of the SP receptor blocker.

  4. BLOCKADE OF NERVE GROWTH FACTOR (NGF) RECEPTOR TRKA ATTENUATES DIESEL EXHAUST PARTICULATE MATTER (DEP) ENHANCEMENT OF ALLERGIC INFLAMMATION

    EPA Science Inventory


    Recent studies have shown that asthmatics have increased levels of the neurotrophin, NGF, in their lungs. In addition, antibody blockade of NGF in mice attenuates airway resistance associated with allergic airway responses. DEP has been linked to asthma exacerbation in many c...

  5. BLOCKADE OF NERVE GROWTH FACTOR (NGF) RECEPTOR TRKA ATTENUATES DIESEL EXHAUST PARTICULATE MATTER (DEP) ENHANCEMENT OF ALLERGIC INFLAMMATION

    EPA Science Inventory


    Recent studies have shown that asthmatics have increased levels of the neurotrophin, NGF, in their lungs. In addition, antibody blockade of NGF in mice attenuates airway resistance associated with allergic airway responses. DEP has been linked to asthma exacerbation in many c...

  6. Enhanced apomorphine sensitivity and increased binding of dopamine D2 receptors in nucleus accumbens in prepubertal rats after neonatal blockade of the dopamine D3 receptors by (+)-S14297.

    PubMed

    Flores-Tochihuitl, Julia; Vargas, Guillermo; Morales-Medina, Julio Cesar; Rivera, Gustavo; De La Cruz, Fidel; Zamudio, Sergio; Flores, Gonzalo

    2008-01-01

    The role of dopamine (DA) D3 receptors is controversial in early developmental stages of specially locomotor activity. Past studies have only tested behavioral changes induced by neonatal administration of nonselective dopamine antagonist such as haloperidol or sulpiride in adult rats. We investigated the role of neonatal blockade of DA D3 receptors at (postnatal day, P1 to P12) using the DA D3 receptor antagonist (+)-S14297 on paradigms related to DA behaviors including locomotor activity in novel environment and after administration of the DA nonspecific agonists d-amphetamine, and apomorphine. Additionally, autoradiographic studies were performed to correlate behavioral alterations with DA D1-like, D2-like, and D3 receptors. All studies were performed at two critical ages, prepubertal (P35) and postpubertal (P60). The quantitative autoradiogaphic study revealed increases in the expression of DA D2-like receptor expression in the nucleus accumbens (NAcc) in prepubertal animals that received the DA D3 antagonist (+)-S14297 at neonatal age. In addition, novel environment and apomorphine administration (0.5 mg/kg, s.c.), induced increases of locomotor activity in prepubertal animals that received the DA D3 antagonist (+)-S14297. Autoradiographic and behavioral results suggest that blockade of DA D3 receptors after birth may mediate different neurodevelopmental aspects of the dopaminergic pathway before and after puberty. (c) 2007 Wiley-Liss, Inc.

  7. The effect of neonatal N-methyl-D-aspartate receptor blockade on exploratory and anxiety-like behaviors in adult BALB/c and C57BL/6 mice.

    PubMed

    Akillioglu, Kubra; Binokay, Secil; Kocahan, Sayad

    2012-07-15

    N-methyl-D-aspartate (NMDA) receptors play an important role in brain maturation and developmental processes. In our study, we evaluated the effects of neonatal NMDA receptor blockade on exploratory locomotion and anxiety-like behaviors of adult BALB/c and C57BL/6 mice. In this study, NMDA receptor hypofunction was induced 7-10 days after birth using MK-801 in BALB/c and C57BL/6 mice (0.25mg/kg twice a day for 4 days via intraperitoneal injection). The open-field (OF) and elevated plus maze (EPM) tests were used to evaluate exploratory locomotion and anxiety-like behaviors. In the OF, BALB/c mice spent less time in the center of the field (p<0.05) and had less vertical locomotor activity (p<0.01) compared to C57BL/6 mice. In BALB/c mice, MK-801 caused a decrease in vertical and horizontal locomotor activity in the OF test, compared to the control group (p<0.05). In C57BL/6 mice, MK-801 treatment increased horizontal locomotor activity and decreased time spent in the center in the OF test (p<0.05). In the EPM, the number of open-arm entries, the percentage of open-arm time (p<0.01) and total arm entries (p<0.05) were lower in BALB/c mice compared to C57BL/6 mice. In BALB/c mice, MK-801 caused an increase in the percentage of open-arm time compared to the control group (p<0.05). In C57BL/6 mice, MK-801 caused a decrease in the percentage of open-arm time compared to the control group (p<0.05). MK-801 decreased exploratory and anxiety-like behaviors in BALB/c mice. In contrast, MK-801 increased exploratory and anxiety-like behaviors in C57BL/6 mice. In conclusion, hereditary factors may play an important role in neonatal NMDA receptor blockade-induced responses. Copyright © 2012 Elsevier B.V. All rights reserved.

  8. Effects of Long-term Blockade of Vasopressin Receptor Types 1a and 2 on Cardiac and Renal Damage in a Rat Model of Hypertensive Heart Failure.

    PubMed

    Ikeda, Tomoyuki; Iwanaga, Yoshitaka; Watanabe, Heitaro; Morooka, Hanako; Akahoshi, Yasumitsu; Fujiki, Hiroyuki; Miyazaki, Shunichi

    2015-11-01

    The effects of chronic blockade of vasopressin type 1a receptors (V1aR) and the additive effects of a type 2 receptor (V2R) antagonist on the treatment of hypertension-induced heart failure and renal injury remain to be unknown. In this study, Dahl salt-sensitive hypertensive rats were chronically treated with a vehicle (CONT), a V1aR antagonist (OPC21268; OPC), a V2R antagonist (tolvaptan; TOLV), or a combination of OPC21268 and tolvaptan (OPC/TOLV) from the pre-hypertrophic stage (6 weeks). No treatment altered blood pressure during the study. Significant improvements were seen in median survival for the OPC and TOLV, and the OPC/TOLV showed a further improvement in Kaplan-Meier analysis. Echocardiography showed suppressed left ventricular hypertrophy in the OPC and OPC/TOLV at 11 weeks with improved function in all treatment groups by 17 weeks. In all treatment groups, improvements were seen in the following: myocardial histological changes, creatinine clearance, urinary albumin excretion, and renal histopathologic damage. Also, key mRNA levels were suppressed (eg, endothelin-1 and collagen). In conclusion, chronic V1aR blockade ameliorated disease progression in this rat model, with additive benefits from the combination of V1aR and V2R antagonists. It was associated with protection of both myocardial and renal damage, independent of blood pressure.

  9. Angiotensin II AT1 receptor blockade by telmisartan reduces impairment of spatial maze performance induced by both acute and chronic stress.

    PubMed

    Wincewicz, Dominik; Braszko, Jan J

    2015-09-01

    Despite recognition of stress as a causation of severe neuropsychological dysfunctions, no casual and clinically effective anti-stress therapeutic strategy has yet been found. We have previously shown that blockade of initial stress response by angiotensin receptor blockers alleviates the negative effect of prolonged stress on cognitive non-spatial functions of rats. Here we aimed to find whether telmisartan reduces stress-related memory decline in spatial hippocampal-dependent learning tasks conditioned upon differences in level of stress induced by aversive nature of memory tests. Male Wistar rats were exposed to chronic restraint stress for three weeks and daily treated with either vehicle or telmisartan (1 mg/kg). Afterwards rats were tested in three spatial learning and memory paradigms: Morris water maze (MWM), radial arm maze (RAM), and Barnes maze (BM). Stressed animals demonstrated significantly impaired performance in all the tests, which was normalized in the animals stressed and treated with telmisartan. Interestingly, despite the fact that MWM and RAM are more stressful, which affects animal behavior, therefore considered less sensitive than BM, more significant effect of telmisartan was found in MWM and RAM than BM. AT1 angiotensin receptor blockade attenuates negative effect of both acute and chronic stress on spatial memory. © The Author(s) 2014.

  10. Environmental-Induced Differences in Corticosterone and Glucocorticoid Receptor Blockade of Amphetamine Self-Administration in Rats

    PubMed Central

    Stairs, Dustin J.; Prendergast, Mark A.; Bardo, Michael T.

    2011-01-01

    Rationale Rats raised in isolation self-administer more amphetamine than rats raised in enrichment. Objective This study examined whether differential rearing alters basal and amphetamine-stimulated corticosterone and whether blocking glucocorticoid receptors alters amphetamine self-administration in differentially reared rats. Methods Rats were raised from 21–51 days of age in either an enriched condition (EC), social condition (SC) or isolated condition (IC). Following repeated collection of basal blood samples, rats were administered amphetamine (0.5 or 2.0 mg/kg, i.p.) or saline, and blood samples were collected again. In another experiment, EC and IC rats were trained to self-administer i.v. amphetamine (0.003 or 0.03 mg/kg/infusion) and then were pretreated with the glucocorticoid receptor antagonist RU-486 (5, 10 or 20 mg/kg; i.p.) or vehicle prior to the session. Results Basal free corticosterone levels were ~4 times higher in IC rats than in either EC or SC rats with the first blood collection, but not with repeated collections. IC rats showed a more rapid amphetamine-induced increase in corticosterone levels than EC and SC rats. RU-486 pretreatment decreased amphetamine self-administration dose-dependently in both EC and IC rats; however, using an amphetamine unit dose of 0.03 mg/kg/infusion, the effect of RU-486 was blunted in IC rats (maximal decrease of ~40% in IC and ~90% in EC), suggesting an environment-induced difference in the role of glucocorticoid receptors in stimulant reinforcement. Conclusion The increase in stimulant self-administration produced by social isolation may involve enhanced reactivity of the hypothalamo-pituitary-adrenal stress axis. PMID:21887496

  11. Oxytocin receptor blockade reduces acquisition but not retrieval of taste aversion and blunts responsiveness of amygdala neurons to an aversive stimulus.

    PubMed

    Olszewski, Pawel K; Waas, Joseph R; Brooks, Lydia L; Herisson, Florence; Levine, Allen S

    2013-12-01

    When gastrointestinal sickness induced by toxin injection is associated with exposure to novel food, the animal acquires a conditioned taste aversion (CTA). Malaise is accompanied by a surge in oxytocin release and in oxytocin neuronal activity; however, it is unclear whether oxytocin is a key facilitator of aversion or merely its marker. Herein we investigated whether blockade of the oxytocin receptor with the blood-brain barrier penetrant oxytocin receptor antagonist L-368,899 is detrimental for the acquisition and/or retrieval of lithium chloride (LiCl)-dependent CTA to a saccharin solution in mice. We also examined whether L-368,899 given prior to LiCl affects neuronal activity defined through c-Fos immunohistochemistry in select brain sites facilitating CTA acquisition. L-368,899 given prior to LiCl caused a 30% increase in saccharin solution intake in a two-bottle test, but when the antagonist was administered before the two-bottle test, it failed to diminish the retrieval of an existing CTA. LiCl administration increased c-Fos expression in the hypothalamic paraventricular and supraoptic nuclei, area postrema, nucleus of the solitary tract and basolateral and central (CNA) nuclei of the amygdala. L-368,899 injected before LiCl reduced the number of c-Fos positive CNA neurons and brought it down to levels similar to those observed in mice treated only with L-368,899. We conclude that oxytocin is one of the key components in acquisition of LiCl-induced CTA and the aversive response can be alleviated by the oxytocin receptor blockade. Oxytocin receptor antagonism blunts responsiveness of CNA to peripherally injected LiCl. Copyright © 2013 Elsevier Inc. All rights reserved.

  12. Widespread decreases in cortical muscarinic receptors in a subset of people with schizophrenia.

    PubMed

    Gibbons, Andrew Stuart; Scarr, Elizabeth; Boer, Simone; Money, Tammie; Jeon, Won-Je; Felder, Chris; Dean, Brian

    2013-02-01

    These studies were undertaken to investigate the selectivity of cortical muscarinic receptor radioligand binding in muscarinic M(1) and M(4) receptor knockout mice and to determine whether a marked decrease in [(3)H]pirenzepine binding in Brodmann's area (BA) 9 from a subset of people with schizophrenia was predictive of decreased muscarinic receptors in other central nervous system (CNS) regions. Our data show that, under the conditions used, [(3)H]pirenzepine binding was highly selective for the muscarinic M(1) receptor whereas both [(3)H]AF-DX 386 and [(3)H]4DAMP had less discriminatory power. In addition, the data suggest that a marked decrease in [(3)H]pirenzepine binding in BA 9 from a subset of people with schizophrenia is predictive of decreases in muscarinic receptors in other CNS regions. However, there were some region-specific decreases in muscarinic receptors in tissue from people with schizophrenia who were outside this subset. These data add to a growing body of evidence suggesting there are widespread decreases in muscarinic receptors in the CNS of some subjects with schizophrenia, as demonstrated by neuroimaging. Our data have implications for understanding the potential clinical utility of drugs directed at the orthosteric and allosteric sites of muscarinic receptors to treat schizophrenia.

  13. CXCL12/CXCR4 blockade by oncolytic virotherapy inhibits ovarian cancer growth by decreasing immunosuppression and targeting cancer-initiating cells.

    PubMed

    Gil, Margaret; Komorowski, Marcin P; Seshadri, Mukund; Rokita, Hanna; McGray, A J Robert; Opyrchal, Mateusz; Odunsi, Kunle O; Kozbor, Danuta

    2014-11-15

    Signals mediated by the chemokine CXCL12 and its receptor CXCR4 are involved in the progression of ovarian cancer through enhancement of tumor angiogenesis and immunosuppressive networks that regulate dissemination of peritoneal metastasis and development of cancer-initiating cells (CICs). In this study, we investigated the antitumor efficacy of a CXCR4 antagonist expressed by oncolytic vaccinia virus (OVV) against an invasive variant of the murine epithelial ovarian cancer cell line ID8-T. This variant harbors a high frequency of CICs that form multilayered spheroid cells and express the hyaluronan receptor CD44, as well as stem cell factor receptor CD117 (c-kit). Using an orthotopic ID8-T tumor model, we observed that i.p. delivery of a CXCR4 antagonist-expressing OVV led to reduced metastatic spread of tumors and improved overall survival compared with oncolysis alone. Inhibition of tumor growth with the armed virus was associated with efficient killing of CICs, reduced expression of ascitic CXCL12 and vascular endothelial growth factor, and decreases in i.p. numbers of endothelial and myeloid cells, as well as plasmacytoid dendritic cells. These changes, together with reduced recruitment of T regulatory cells, were associated with higher ratios of IFN-γ(+)/IL-10(+) tumor-infiltrating T lymphocytes, as well as induction of spontaneous humoral and cellular antitumor responses. Similarly, the CXCR4 antagonist released from virally infected human CAOV2 ovarian carcinoma cells inhibited peritoneal dissemination of tumors in SCID mice, leading to improved tumor-free survival in a xenograft model. Our findings demonstrate that OVV armed with a CXCR4 antagonist represents a potent therapy for ovarian CICs with a broad antitumor repertoire.

  14. CXCL12/CXCR4 Blockade by Oncolytic Virotherapy Inhibits Ovarian Cancer Growth by Decreasing Immunosuppression and Targeting Cancer Initiating Cells1

    PubMed Central

    Gil, Margaret; Komorowski, Marcin P.; Seshadri, Mukund; Rokita, Hanna; McGray, A. J Robert; Opyrchal, Mateusz; Odunsi, Kunle O.; Kozbor, Danuta

    2014-01-01

    Signals mediated by the chemokine CXCL12 and its receptor CXCR4 are involved in progression of ovarian cancer by enhancing tumor angiogenesis and immunosuppressive networks that regulate dissemination of peritoneal metastasis and development of cancer initiating cells (CICs). Here, we investigated the antitumor efficacy of a CXCR4 antagonist expressed by oncolytic vaccinia virus (OVV) against an invasive variant of the murine epithelial ovarian cancer cell line ID8-T. This variant harbors a high frequency of CICs that form multilayered spheroid cells and express the hyaluronan receptor CD44 as well as stem cell factor receptor CD117 (c-kit). Using an orthotopic ID8-T tumor model, we observed that intraperitoneal delivery of a CXCR4 antagonist-expressing OVV led to reduced metastatic spread of tumors and improved overall survival over that mediated by oncolysis alone. Inhibition of tumor growth with the armed virus was associated with efficient killing of CICs, reductions in expression of ascitic CXCL12 and VEGF, and decreases in intraperitoneal numbers of endothelial and myeloid cells as well as plasmacytoid dendritic cells (pDCs). These changes, together with reduced recruitment of T regulatory cells, were associated with higher ratios of IFN-γ+/IL-10+ tumor-infiltrating T lymphocytes as well as induction of spontaneous humoral and cellular antitumor responses. Similarly, the CXCR4 antagonist released from virally-infected human CAOV2 ovarian carcinoma cells inhibited peritoneal dissemination of tumors in SCID mice leading to improved tumor-free survival in a xenograft model. Our findings demonstrate that OVV armed with a CXCR4 antagonist represents a potent therapy for ovarian CICs with a broad antitumor repertoire. PMID:25320277

  15. Embryonic GABA(B) receptor blockade alters cell migration, adult hypothalamic structure, and anxiety- and depression-like behaviors sex specifically in mice.

    PubMed

    Stratton, Matthew S; Staros, Michelle; Budefeld, Tomaz; Searcy, Brian T; Nash, Connor; Eitel, Chad; Carbone, David; Handa, Robert J; Majdic, Gregor; Tobet, Stuart A

    2014-01-01

    Neurons of the paraventricular nucleus of the hypothalamus (PVN) regulate the hypothalamic- pituitary-adrenal (HPA) axis and the autonomic nervous system. Females lacking functional GABA(B) receptors because of a genetic disruption of the R1 subunit have altered cellular characteristics in and around the PVN at birth. The genetic disruption precluded appropriate assessments of physiology or behavior in adulthood. The current study was conducted to test the long term impact of a temporally restricting pharmacological blockade of the GABA(B) receptor to a 7-day critical period (E11-E17) during embryonic development. Experiments tested the role of GABA(B) receptor signaling in fetal development of the PVN and later adult capacities for adult stress related behaviors and physiology. In organotypic slices containing fetal PVN, there was a female specific, 52% increase in cell movement speeds with GABA(B) receptor antagonist treatment that was consistent with a sex-dependent lateral displacement of cells in vivo following 7 days of fetal exposure to GABA(B) receptor antagonist. Anxiety-like and depression-like behaviors, open-field activity, and HPA mediated responses to restraint stress were measured in adult offspring of mothers treated with GABA(B) receptor antagonist. Embryonic exposure to GABA(B) receptor antagonist resulted in reduced HPA axis activation following restraint stress and reduced depression-like behaviors. There was also increased anxiety-like behavior selectively in females and hyperactivity in males. A sex dependent response to disruptions of GABA(B) receptor signaling was identified for PVN formation and key aspects of physiology and behavior. These changes correspond to sex specific prevalence in similar human disorders, namely anxiety disorders and hyperactivity.

  16. Embryonic GABAB Receptor Blockade Alters Cell Migration, Adult Hypothalamic Structure, and Anxiety- and Depression-Like Behaviors Sex Specifically in Mice

    PubMed Central

    Stratton, Matthew S.; Staros, Michelle; Budefeld, Tomaz; Searcy, Brian T.; Nash, Connor; Eitel, Chad; Carbone, David; Handa, Robert J.; Majdic, Gregor; Tobet, Stuart A.

    2014-01-01

    Neurons of the paraventricular nucleus of the hypothalamus (PVN) regulate the hypothalamic- pituitary-adrenal (HPA) axis and the autonomic nervous system. Females lacking functional GABAB receptors because of a genetic disruption of the R1 subunit have altered cellular characteristics in and around the PVN at birth. The genetic disruption precluded appropriate assessments of physiology or behavior in adulthood. The current study was conducted to test the long term impact of a temporally restricting pharmacological blockade of the GABAB receptor to a 7-day critical period (E11–E17) during embryonic development. Experiments tested the role of GABAB receptor signaling in fetal development of the PVN and later adult capacities for adult stress related behaviors and physiology. In organotypic slices containing fetal PVN, there was a female specific, 52% increase in cell movement speeds with GABAB receptor antagonist treatment that was consistent with a sex-dependent lateral displacement of cells in vivo following 7 days of fetal exposure to GABAB receptor antagonist. Anxiety-like and depression-like behaviors, open-field activity, and HPA mediated responses to restraint stress were measured in adult offspring of mothers treated with GABAB receptor antagonist. Embryonic exposure to GABAB receptor antagonist resulted in reduced HPA axis activation following restraint stress and reduced depression-like behaviors. There was also increased anxiety-like behavior selectively in females and hyperactivity in males. A sex dependent response to disruptions of GABAB receptor signaling was identified for PVN formation and key aspects of physiology and behavior. These changes correspond to sex specific prevalence in similar human disorders, namely anxiety disorders and hyperactivity. PMID:25162235

  17. Dual Endothelin-A/Endothelin-B Receptor Blockade and Cardiac Remodeling in Heart Failure With Preserved Ejection Fraction.

    PubMed

    Valero-Munoz, Maria; Li, Shanpeng; Wilson, Richard M; Boldbaatar, Batbold; Iglarz, Marc; Sam, Flora

    2016-11-01

    Despite the increasing prevalence of heart failure with preserved ejection fraction (HFpEF) in humans, there remains no evidence-based therapies for HFpEF. Endothelin-1 (ET-1) antagonists are a possibility because elevated ET-1 levels are associated with adverse cardiovascular effects, such as arterial and pulmonary vasoconstriction, impaired left ventricular (LV) relaxation, and stimulation of LV hypertrophy. LV hypertrophy is a common phenotype in HFpEF, particularly when associated with hypertension. In the present study, we found that ET-1 levels were significantly elevated in patients with chronic stable HFpEF. We then sought to investigate the effects of chronic macitentan, a dual ET-A/ET-B receptor antagonist, on cardiac structure and function in a murine model of HFpEF induced by chronic aldosterone infusion. Macitentan caused LV hypertrophy regression independent of blood pressure changes in HFpEF. Although macitentan did not modulate diastolic dysfunction in HFpEF, it significantly reduced wall thickness and relative wall thickness after 2 weeks of therapy. In vitro studies showed that macitentan decreased the aldosterone-induced cardiomyocyte hypertrophy. These changes were mediated by a reduction in the expression of cardiac myocyte enhancer factor 2a. Moreover, macitentan improved adverse cardiac remodeling, by reducing the stiffer cardiac collagen I and titin n2b expression in the left ventricle of mice with HFpEF. These findings indicate that dual ET-A/ET-B receptor inhibition improves HFpEF by abrogating adverse cardiac remodeling via antihypertrophic mechanisms and by reducing stiffness. Additional studies are needed to explore the role of dual ET-1 receptor antagonists in patients with HFpEF. © 2016 American Heart Association, Inc.

  18. Dual Endothelin-A/Endothelin-B Receptor Blockade and Cardiac Remodeling in Heart Failure With Preserved Ejection Fraction

    PubMed Central

    Valero-Munoz, Maria; Li, Shanpeng; Wilson, Richard M.; Boldbaatar, Batbold; Iglarz, Marc; Sam, Flora

    2017-01-01

    Background Despite the increasing prevalence of heart failure with preserved ejection fraction (HFpEF) in humans, there remains no evidence-based therapies for HFpEF. Endothelin-1 (ET-1) antagonists are a possibility because elevated ET-1 levels are associated with adverse cardiovascular effects, such as arterial and pulmonary vasoconstriction, impaired left ventricular (LV) relaxation, and sti