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

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Roderick J Tan

Full Text Available 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.

Age dependence of the rapid antidepressant and synaptic effects of acute NMDA receptor blockade

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Elena eNosyreva

2014-12-01

Full Text Available Ketamine is a NMDA receptor antagonist that produces rapid antidepressant responses in individuals with major depressive disorder. The antidepressant action of ketamine has been linked to blocking NMDA receptor activation at rest, which inhibits eukaryotic elongation factor2 kinase leading to desuppression of protein synthesis and synaptic potentiation in the CA1 region of the hippocampus. Here, we investigated ketamine mediated antidepressant response and the resulting synaptic potentiation in juvenile animals. We found that ketamine did not produce an antidepressant response in juvenile animals in the novelty suppressed feeding or the forced swim test. In addition ketamine application failed to trigger synaptic potentiation in hippocampal slices obtained from juvenile animals, unlike its action in slices from older animals (6-9 weeks old. The inability of ketamine to trigger an antidepressant response or subsequent synaptic plasticity processes suggests a developmental component to ketamine mediated antidepressant efficacy. We also show that the NMDAR antagonist AP5 triggers synaptic potentiation in mature hippocampus similar to the action of ketamine, demonstrating that global competitive blockade of NMDA receptors is sufficient to trigger this effect. These findings suggest that global blockade of NMDA receptors in developmentally mature hippocampal synapses are required for the antidepressant efficacy of ketamine.

Effects of angiotensin II receptor blockade on cerebral, cardiovascular, counter-regulatory, and symptomatic responses during hypoglycaemia in patients with type 1 diabetes

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Færch, Louise H; Thorsteinsson, Birger; Tarnow, Lise

2015-01-01

INTRODUCTION: High spontaneous activity of the renin-angiotensin system (RAS) results in more pronounced cognitive impairment and more prolonged QTc interval during hypoglycaemia in type 1 diabetes. We tested whether angiotensin II receptor blockade improves cerebral and cardiovascular function d...

The physiological role of AT1 receptors in the ventrolateral medulla

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T. Tagawa

2000-06-01

Full Text Available Neurons in the rostral and caudal parts of the ventrolateral medulla (VLM play a pivotal role in the regulation of sympathetic vasomotor activity and blood pressure. Studies in several species, including humans, have shown that these regions contain a high density of AT1 receptors specifically associated with neurons that regulate the sympathetic vasomotor outflow, or the secretion of vasopressin from the hypothalamus. It is well established that specific activation of AT1 receptors by application of exogenous angiotensin II in the rostral and caudal VLM excites sympathoexcitatory and sympathoinhibitory neurons, respectively, but the physiological role of these receptors in the normal synaptic regulation of VLM neurons is not known. In this paper we review studies which have defined the effects of specific activation or blockade of these receptors on cardiovascular function, and discuss what these findings tell us with regard to the physiological role of AT1 receptors in the VLM in the tonic and phasic regulation of sympathetic vasomotor activity and blood pressure.

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

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Hellsten, Ylva; Krustrup, Peter; Iaia, F Marcello

2009-01-01

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 k......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...... 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 hyperaemia 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 fibres. Key words: blood flow, neuromuscular blockade, exercise, skeletal muscle....

Angiotensin II type 1 receptor blockade partially attenuates hypoxia-induced pulmonary hypertension in newborn piglets: relationship with the nitrergic system

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Camelo, J.S. Jr. [Departamento de Puericultura e Pediatria, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP (Brazil); Martins, A.R. [Departamento de Farmacologia, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP (Brazil); Instituto de Ciências Biológicas, Universidade Federal do Triângulo Mineiro, Uberaba, MG (Brazil); Rosa, E. [Departamento de Farmacologia, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP (Brazil); Ramos, S.G. [Departamento de Patologia, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SPBrasil (Brazil); Hehre, D.; Bancalari, E.; Suguihara, C. [Department of Pediatrics, Division of Neonatology, Neonatal Developmental Biology Laboratory, University of Miami Miller School of Medicine, Miami, FL (United States)

2012-02-10

The objective of this study was to observe possible interactions between the renin-angiotensin and nitrergic systems in chronic hypoxia-induced pulmonary hypertension in newborn piglets. Thirteen chronically instrumented newborn piglets (6.3 ± 0.9 days; 2369 ± 491 g) were randomly assigned to receive saline (placebo, P) or the AT{sub 1} receptor (AT{sub 1}-R) blocker L-158,809 (L) during 6 days of hypoxia (FiO{sub 2} = 0.12). During hypoxia, pulmonary arterial pressure (Ppa; P < 0.0001), pulmonary vascular resistance (PVR; P < 0.02) and the pulmonary to systemic vascular resistance ratio (PVR/SVR; P < 0.05) were significantly attenuated in the L (N = 7) group compared to the P group (N = 6). Western blot analysis of lung proteins showed a significant decrease of endothelial NOS (eNOS) in both P and L animals, and of AT{sub 1}-R in P animals during hypoxia compared to normoxic animals (C group, N = 5; P < 0.01 for all groups). AT{sub 1}-R tended to decrease in L animals. Inducible NOS (iNOS) did not differ among P, L, and C animals and iNOS immunohistochemical staining in macrophages was significantly more intense in L than in P animals (P < 0.01). The vascular endothelium showed moderate or strong eNOS and AT{sub 1}-R staining. Macrophages and pneumocytes showed moderate or strong iNOS and AT{sub 1}-R staining, but C animals showed weak iNOS and AT{sub 1}-R staining. Macrophages of L and P animals showed moderate and weak AT{sub 2}-R staining, respectively, but the endothelium of all groups only showed weak staining. In conclusion, pulmonary hypertension induced by chronic hypoxia in newborn piglets is partially attenuated by AT{sub 1}-R blockade. We suggest that AT{sub 1}-R blockade might act through AT{sub 2}-R and/or Mas receptors and the nitrergic system in the lungs of hypoxemic newborn piglets.

Angiotensin II type 1 receptor blockade by telmisartan prevents stress-induced impairment of memory via HPA axis deactivation and up-regulation of brain-derived neurotrophic factor gene expression.

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Wincewicz, D; Juchniewicz, A; Waszkiewicz, N; Braszko, J J

2016-09-01

Physical and psychological aspects of chronic stress continue to be a persistent clinical problem for which new pharmacological treatment strategies are aggressively sought. By the results of our previous work it has been demonstrated that telmisartan (TLM), an angiotensin type 1 receptor (AT1) blocker (ARB) and partial agonist of peroxisome proliferator-activated receptor gamma (PPARγ), alleviates stress-induced cognitive decline. Understanding of mechanistic background of this phenomenon is hampered by both dual binding sites of TLM and limited data on the consequences of central AT1 blockade and PPARγ activation. Therefore, a critical need exists for progress in the characterization of this target for pro-cognitive drug discovery. An unusual ability of novel ARBs to exert various PPARγ binding activities is commonly being viewed as predominant over angiotensin blockade in terms of neuroprotection. Here we aimed to verify this hypothesis using an animal model of chronic psychological stress (Wistar rats restrained 2.5h daily for 21days) with simultaneous oral administration of TLM (1mg/kg), GW9662 - PPARγ receptor antagonist (0.5mg/kg), or both in combination, followed by a battery of behavioral tests (open field, elevated plus maze, inhibitory avoidance - IA, object recognition - OR), quantitative determination of serum corticosterone (CORT) and evaluation of brain-derived neurotrophic factor (BDNF) gene expression in the medial prefrontal cortex (mPFC) and hippocampus (HIP). Stressed animals displayed decreased recall of the IA behavior (pBDNF in the mPFC (paxis deactivation associated with changes in primarily cortical gene expression. This study confirms the dual activities of TLM that controls hypertension and cognition through AT1 blockade. Copyright © 2016 Elsevier Inc. All rights reserved.

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

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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.

Dietary restriction but not angiotensin II type 1 receptor blockade improves DNA damage-related vasodilator dysfunction in rapidly aging Ercc1Δ/- mice.

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Wu, Haiyan; van Thiel, Bibi S; Bautista-Niño, Paula K; Reiling, Erwin; Durik, Matej; Leijten, Frank P J; Ridwan, Yanto; Brandt, Renata M C; van Steeg, Harry; Dollé, Martijn E T; Vermeij, Wilbert P; Hoeijmakers, Jan H J; Essers, Jeroen; van der Pluijm, Ingrid; Danser, A H Jan; Roks, Anton J M

2017-08-01

DNA damage is an important contributor to endothelial dysfunction and age-related vascular disease. Recently, we demonstrated in a DNA repair-deficient, prematurely aging mouse model ( Ercc1 Δ/- mice) that dietary restriction (DR) strongly increases life- and health span, including ameliorating endothelial dysfunction, by preserving genomic integrity. In this mouse mutant displaying prominent accelerated, age-dependent endothelial dysfunction we investigated the signaling pathways involved in improved endothelium-mediated vasodilation by DR, and explore the potential role of the renin-angiotensin system (RAS). Ercc1 Δ/- mice showed increased blood pressure and decreased aortic relaxations to acetylcholine (ACh) in organ bath experiments. Nitric oxide (NO) signaling and phospho-Ser 1177 -eNOS were compromised in Ercc1 Δ / - DR improved relaxations by increasing prostaglandin-mediated responses. Increase of cyclo-oxygenase 2 and decrease of phosphodiesterase 4B were identified as potential mechanisms. DR also prevented loss of NO signaling in vascular smooth muscle cells and normalized angiotensin II (Ang II) vasoconstrictions, which were increased in Ercc1 Δ/- mice. Ercc1 Δ/ - mutants showed a loss of Ang II type 2 receptor-mediated counter-regulation of Ang II type 1 receptor-induced vasoconstrictions. Chronic losartan treatment effectively decreased blood pressure, but did not improve endothelium-dependent relaxations. This result might relate to the aging-associated loss of treatment efficacy of RAS blockade with respect to endothelial function improvement. In summary, DR effectively prevents endothelium-dependent vasodilator dysfunction by augmenting prostaglandin-mediated responses, whereas chronic Ang II type 1 receptor blockade is ineffective. © 2017 The Author(s). Published by Portland Press Limited on behalf of the Biochemical Society.

Renoprotective effects of angiotensin II receptor blockade in type 1 diabetic patients with diabetic nephropathy

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Andersen, S; Tarnow, L; Rossing, P

2000-01-01

BACKGROUND: Angiotensin I-converting enzyme (ACE) inhibitors reduce angiotensin II formation and induce bradykinin accumulation. Animal studies suggest that bradykinin may play a role for the effects of ACE inhibition on blood pressure and kidney function. Therefore, we compared the renal and hem...... inhibition is primarily caused by interference in the renin-angiotensin system. Our study suggest that losartan represents a valuable new drug in the treatment of hypertension and proteinuria in type 1 diabetic patients with diabetic nephropathy....... and hemodynamic effects of specific intervention in the renin-angiotensin system by blockade of the angiotensin II subtype-1 receptor to the effect of ACE inhibition. METHODS: A randomized, double-blind, cross-over trial was performed in 16 type 1 diabetic patients (10 men), age 42 +/- 2 years (mean +/- SEM...

Normotensive sodium loading in conscious dogs: Regulation of renin secretion during beta receptor blockade

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Bie, Peter; Mølstrøm, Simon; Wamberg, Søren

2009-01-01

Cl (20 micromol/kg/min for 180 min, NaLoad) during regular or low-sodium diet (0.03 mmol/kg/d, LowNa) with and without metoprolol (2 mg/kg plus 0.9 mg/kg/h). Vasopressin V2 receptors were blocked by Otsuka compound OPC31260 to facilitate clearance measurements. Body fluid volume was maintained by servo-controlled...... that in this setting, renin secretion and renin-dependent sodium excretion are controlled by via the renal nerves and therefore 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 Na...... irrespective 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...

Human CAR T cells with cell-intrinsic PD-1 checkpoint blockade resist tumor-mediated inhibition

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Cherkassky, Leonid; Morello, Aurore; Villena-Vargas, Jonathan; Feng, Yang; Dimitrov, Dimiter S.; Jones, David R.; Sadelain, Michel; Adusumilli, Prasad S.

2016-01-01

Following immune attack, solid tumors upregulate coinhibitory ligands that bind to inhibitory receptors on T cells. This adaptive resistance compromises the efficacy of chimeric antigen receptor (CAR) T cell therapies, which redirect T cells to solid tumors. Here, we investigated whether programmed death-1–mediated (PD-1–mediated) T cell exhaustion affects mesothelin-targeted CAR T cells and explored cell-intrinsic strategies to overcome inhibition of CAR T cells. Using an orthotopic mouse model of pleural mesothelioma, we determined that relatively high doses of both CD28- and 4-1BB–based second-generation CAR T cells achieved tumor eradication. CAR-mediated CD28 and 4-1BB costimulation resulted in similar levels of T cell persistence in animals treated with low T cell doses; however, PD-1 upregulation within the tumor microenvironment inhibited T cell function. At lower doses, 4-1BB CAR T cells retained their cytotoxic and cytokine secretion functions longer than CD28 CAR T cells. The prolonged function of 4-1BB CAR T cells correlated with improved survival. PD-1/PD-1 ligand [PD-L1] pathway interference, through PD-1 antibody checkpoint blockade, cell-intrinsic PD-1 shRNA blockade, or a PD-1 dominant negative receptor, restored the effector function of CD28 CAR T cells. These findings provide mechanistic insights into human CAR T cell exhaustion in solid tumors and suggest that PD-1/PD-L1 blockade may be an effective strategy for improving the potency of CAR T cell therapies. PMID:27454297

Toll-like receptor 3 blockade in rhinovirus-induced experimental asthma exacerbations

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Silkoff, Philip E; Flavin, Susan; Gordon, Robert

2017-01-01

BACKGROUND: Human rhinoviruses (HRVs) commonly precipitate asthma exacerbations. Toll-like receptor 3, an innate pattern recognition receptor, is triggered by HRV, driving inflammation that can worsen asthma. OBJECTIVE: We sought to evaluate an inhibitory mAb to Toll-like receptor 3, CNTO3157......, respectively, and were then inoculated with HRV-16 within 72 hours. All subjects were monitored for respiratory symptoms, lung function, and nasal viral load. The primary end point was maximal decrease in FEV1 during 10 days after inoculation. RESULTS: In asthmatic patients (n = 63) CNTO3157 provided......: In summary, CNTO3157 was ineffective in attenuating the effect of HRV-16 challenge on lung function, asthma control, and symptoms in asthmatic patients but suppressed cold symptoms in healthy subjects. Other approaches, including blockade of multiple pathways or antiviral agents, need to be sought...

Neonatal blockade of GABA-A receptors alters behavioral and physiological phenotypes in adult mice.

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Salari, Ali-Akbar; Amani, Mohammad

2017-04-01

Gamma-aminobutyric acid (GABA) plays an inhibitory role in the mature brain, and has a complex and bidirectional effect in different parts of the immature brain which affects proliferation, migration and differentiation of neurons during development. There is also increasing evidence suggesting that activation or blockade of the GABA-A receptors during early life can induce brain and behavioral abnormalities in adulthood. We investigated whether neonatal blockade of the GABA-A receptors by bicuculline can alter anxiety- and depression-like behaviors, body weight, food intake, corticosterone and testosterone levels in adult mice (postnatal days 80-95). To this end, neonatal mice were treated with either DMSO or bicuculline (70, 150 and 300μg/kg) during postnatal days 7, 9 and 11. When grown to adulthood, mice were exposed to behavioral tests to measure anxiety- (elevated plus-maze and light-dark box) and depression-like behaviors (tail suspension test and forced swim test). Stress-induced serum corticosterone and testosterone levels, body weight and food intake were also evaluated. Neonatal bicuculline exposure at dose of 300μg/kg decreased anxiety-like behavior, stress-induced corticosterone levels and increased testosterone levels, body weight and food intake, without significantly influencing depression-like behavior in adult male mice. However, no significant changes in these parameters were observed in adult females. These findings suggest that neonatal blockade of GABA-A receptors affects anxiety-like behavior, physiological and hormonal parameters in a sex-dependent manner in mice. Taken together, these data corroborate the concept that GABA-A receptors during early life have an important role in programming neurobehavioral phenotypes in adulthood. Copyright © 2017 ISDN. Published by Elsevier Ltd. All rights reserved.

Sex- and Age-dependent Effects of Orexin 1 Receptor Blockade on Open-Field Behavior and Neuronal Activity.

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Blume, Shannon R; Nam, Hannah; Luz, Sandra; Bangasser, Debra A; Bhatnagar, Seema

2018-06-15

Adolescence is a sensitive and critical period in brain development where psychiatric disorders such as anxiety, depression and post-traumatic stress disorder are more likely to emerge following a stressful life event. Females are two times more likely to suffer from psychiatric disorders than males. Patients with these disorders show alterations in orexins (also called hypocretins), important neuropeptides that regulate arousal, wakefulness and the hypothalamic-pituitary-adrenal axis activity. Little is known on the role of orexins in mediating arousal behaviors in male and female rats during adolescence or adulthood. Here, we examine the influence of orexin 1 receptor blockade by SB334867 in open-field behavior in male and female rats during early adolescence (PND 31-33) or adulthood (PND 75-77). Animals were injected with 0 (vehicle), 1, 10, or 30 mg/kg SB334867 (i.p.). Thirty minutes later, they were placed in an open field, and behavior and neuronal activity (c-Fos) were assessed. In adolescent males, SB334867 significantly increased immobility in the 10 mg/kg group compared to vehicle. However, this increase in immobility in adolescent males was not observed in adolescent females. In contrast to adolescent males, adult males in the 10 mg/kg dose group showed the opposite effect on immobility compared to vehicle. These results indicate that 10 mg/kg dose of SB334867 has opposing effects in adolescent and adult males, but few effects in adolescent and adult females. Differences in functional networks between limbic regions may underlie these effects of orexin receptor blockade that are sex- and age-dependent in rats. Copyright © 2018 IBRO. Published by Elsevier Ltd. All rights reserved.

Predominance of AT1 Blockade Over Mas–Mediated Angiotensin-(1–7) Mechanisms in the Regulation of Blood Pressure and Renin–Angiotensin System in mRen2.Lewis Rats

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2013-01-01

BACKGROUND We investigated whether the antihypertensive actions of the angiotensin II (Ang II) receptor (AT1-R) blocker, olmesartan medoxomil, may in part be mediated by increased Ang-(1–7) in the absence of significant changes in plasma Ang II. METHODS mRen2.Lewis congenic hypertensive rats were administered either a vehicle (n = 14) or olmesartan (0.5mg/kg/day; n = 14) by osmotic minipumps. Two weeks later, rats from both groups were further randomized to receive either the mas receptor antagonist A-779 (0.5mg/kg/day; n = 7 per group) or its vehicle (n = 7 per group) for the next 4 weeks. Blood pressure was monitored by telemetry, and circulating and tissue components of the renin–angiotensin system (RAS) were measured at the completion of the experiments. RESULTS Antihypertensive effects of olmesartan were associated with an increase in plasma renin concentration, plasma Ang I, Ang II, and Ang-(1–7), whereas serum aldosterone levels and kidney Ang II content were reduced. Preserved Ang-(1–7) content in kidneys was associated with increases of ACE2 protein but not activity and no changes on serum and kidney ACE activity. There was no change in cardiac peptide levels after olmesartan treatment. The antihypertensive effects of olmesartan were not altered by concomitant administration of the Ang-(1–7) receptor antagonist except for a mild further increase in plasma renin concentration. CONCLUSIONS Our study highlights the independent regulation of RAS among plasma, heart, and kidney tissue in response to AT1-R blockade. Ang-(1–7) through the mas receptor does not mediate long-term effects of olmesartan besides counterbalancing renin release in response to AT1-R blockade. PMID:23459599

Up-Regulation of Endothelin Type A Receptor in Human and Rat Radiation Proctitis: Preclinical Therapeutic Approach With Endothelin Receptor Blockade

International Nuclear Information System (INIS)

Jullien, Nicolash; Blirando, Karl; Milliat, Fabien; Sabourin, Jean-Christophe; Benderitter, Marc; Francois, Agnes

2009-01-01

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 A ), and ET type B receptor (ET 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 A and ET 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 A /ET B expression and ET A /ET 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 A and ET B in healthy human rectums was similar to that in rat rectums. However, strong ET A immunostaining was seen in the presence of human radiation proctitis, and increased ET A mRNA levels were seen in the rat following colorectal irradiation. Immunostaining for ET 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 A , radiation exposure deregulates the endothelin system through an 'ET A profile' in the human and rodent rectum. However, therapeutic interventions involving mixed or specific ET A receptor blockade do not prevent radiation damage

HTLV-1 specific CD8+ T cell function augmented by blockade of 2B4/CD48 interaction in HTLV-1 infection.

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Chibueze Chioma Ezinne

Full Text Available CD8+ T cell response is important in the response to viral infections; this response though is regulated by inhibitory receptors. Expression of inhibitory receptors has been positively correlated with CD8+ T cell exhaustion; the consequent effect of simultaneous blockade of these inhibitory receptors on CD8+ T cell response in viral infections have been studied, however, the role of individual blockade of receptor-ligand pair is unclear. 2B4/CD48 interaction is involved in CD8+T cell regulation, its signal transducer SAP (signaling lymphocyte activation molecule (SLAM-associated protein is required for stimulatory function of 2B4/CD244 on lymphocytes hence, we analyzed 2B4/CD244 (natural killer cell receptor and SAP (signaling lymphocyte activation molecule(SLAM-associated protein on total CD8+ and HTLV-1 specific CD8+T cells in HTLV-1 infection and the effect of blockade of interaction with ligand CD48 on HTLV-1 specific CD8+ T cell function. We observed a high expression of 2B4/CD244 on CD8+ T cells relative to uninfected and further upregulation on HTLV-1 specific CD8+ T cells. 2B4+ CD8+ T cells exhibited more of an effector and terminally differentiated memory phenotype. Blockade of 2B4/CD48 interaction resulted in improvement in function via perforin expression and degranulation as measured by CD107a surface mobilization on HTLV-1 specific CD8+ T cells. In the light of these findings, we thus propose an inhibitory role for 2B4/CD48 interaction on CD8+T cell function.

Immune cell-poor melanomas benefit from PD-1 blockade after targeted type I IFN activation.

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Bald, Tobias; Landsberg, Jennifer; Lopez-Ramos, Dorys; Renn, Marcel; Glodde, Nicole; Jansen, Philipp; Gaffal, Evelyn; Steitz, Julia; Tolba, Rene; Kalinke, Ulrich; Limmer, Andreas; Jönsson, Göran; Hölzel, Michael; Tüting, Thomas

2014-06-01

Infiltration of human melanomas with cytotoxic immune cells correlates with spontaneous type I IFN activation and a favorable prognosis. Therapeutic blockade of immune-inhibitory receptors in patients with preexisting lymphocytic infiltrates prolongs survival, but new complementary strategies are needed to activate cellular antitumor immunity in immune cell-poor melanomas. Here, we show that primary melanomas in Hgf-Cdk4(R24C) mice, which imitate human immune cell-poor melanomas with a poor outcome, escape IFN-induced immune surveillance and editing. Peritumoral injections of immunostimulatory RNA initiated a cytotoxic inflammatory response in the tumor microenvironment and significantly impaired tumor growth. This critically required the coordinated induction of type I IFN responses by dendritic, myeloid, natural killer, and T cells. Importantly, antibody-mediated blockade of the IFN-induced immune-inhibitory interaction between PD-L1 and PD-1 receptors further prolonged the survival. These results highlight important interconnections between type I IFNs and immune-inhibitory receptors in melanoma pathogenesis, which serve as targets for combination immunotherapies. Using a genetically engineered mouse melanoma model, we demonstrate that targeted activation of the type I IFN system with immunostimulatory RNA in combination with blockade of immune-inhibitory receptors is a rational strategy to expose immune cell-poor tumors to cellular immune surveillance. ©2014 American Association for Cancer Research.

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.

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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 D 1 -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 D 1 -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 D 1 -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 D 1 -family receptors supports the hypothesis that D 1 and/or D 5 receptors could contribute to the mania-relevant behaviors of dopamine transporter knockdown mice.

Muscle-type nicotinic receptor blockade by diethylamine, the hydrophilic moiety of lidocaine

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Armando eAlberola-Die

2016-02-01

Full Text Available Lidocaine bears in its structure both an aromatic ring and a terminal amine, which can be protonated at physiological pH, linked by an amide group. Since lidocaine causes multiple inhibitory actions on nicotinic acetylcholine receptors (nAChRs, this work was aimed to determine the inhibitory effects of diethylamine (DEA, a small molecule resembling the hydrophilic moiety of lidocaine, on Torpedo marmorata nAChRs microtransplanted to Xenopus oocytes. Similarly to lidocaine, DEA reversibly blocked acetylcholine-elicited currents (IACh in a dose-dependent manner (IC50 close to 70 μM, but unlike lidocaine, DEA did not affect IACh desensitization. IACh inhibition by DEA was more pronounced at negative potentials, suggesting an open-channel blockade of nAChRs, although roughly 30% inhibition persisted at positive potentials, indicating additional binding sites outside the pore. DEA block of nAChRs in the resting state (closed channel was confirmed by the enhanced IACh inhibition when pre-applying DEA before its co-application with ACh, as compared with solely DEA and ACh co-application. Virtual docking assays provide a plausible explanation to the experimental observations in terms of the involvement of different sets of drug binding sites. So, at the nAChR transmembrane (TM domain, DEA and lidocaine shared binding sites within the channel pore, giving support to their open-channel blockade; besides, lidocaine, but not DEA, interacted with residues at cavities among the M1, M2, M3 and M4 segments of each subunit and also at intersubunit crevices. At the extracellular (EC domain, DEA and lidocaine binding sites were broadly distributed, which aids to explain the closed channel blockade observed. Interestingly, some DEA clusters were located at the α-γ interphase of the EC domain, in a cavity near the orthosteric binding site pocket; by contrast, lidocaine contacted with all α-subunit loops conforming the ACh binding site, both in α-γ and �

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

Science.gov (United States)

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

Blockade of group II metabotropic glutamate receptors produces hyper-locomotion in cocaine pre-exposed rats by interactions with dopamine receptors.

Science.gov (United States)

Yoon, Hyung Shin; Jang, Ju Kyong; Kim, Jeong-Hoon

2008-09-01

It was previously reported that blockade of group II metabotropic glutamate receptors (mGluRs) produces hyper-locomotion in rats previously exposed to amphetamine, indicating that group II mGluRs are well positioned to modulate the expression of behavioral sensitization by amphetamine. The present study further examined the locomotor activating effects of specific blockade of these receptors after cocaine pre-exposures. First, rats were pre-exposed to seven daily injections of cocaine (15mg/kg, IP). When challenged the next day with an injection of either saline or the group II mGluR antagonist LY341495 (0.5, 1.0 or 2.5mg/kg, IP), they produced hyper-locomotor activity, measured by infrared beam interruptions, to LY341495 compared to saline in a dose-dependent manner. Second, rats were pre-exposed to either saline or seven daily injections of cocaine (15mg/kg, IP). Three weeks later, when they were challenged with an injection of either saline or LY341495 (1.0mg/kg, IP), only rats pre-exposed to cocaine produced hyper-locomotor activity to LY341495 compared to saline. These effects, however, were not present when dopamine D1 (SCH23390; 5 or 10microg/kg), but not D2 (eticlopride; 10 or 50microg/kg), receptor antagonist was pre-injected, indicating that this cocaine-induced hyper-locomotor activity to LY341495 may be mediated in dopamine D1 receptor-dependent manner. These results suggest that group II mGluRs may be adapted to interact with dopaminergic neuronal signaling in mediating the sensitized locomotor activity produced by repeated cocaine pre-exposures.

Integrated molecular analysis of tumor biopsies on sequential CTLA-4 and PD-1 blockade reveals markers of response and resistance

Science.gov (United States)

Roh, Whijae; Chen, Pei-Ling; Reuben, Alexandre; Spencer, Christine N.; Prieto, Peter A.; Miller, John P.; Gopalakrishnan, Vancheswaran; Wang, Feng; Cooper, Zachary A.; Reddy, Sangeetha M.; Gumbs, Curtis; Little, Latasha; Chang, Qing; Chen, Wei-Shen; Wani, Khalida; Petaccia De Macedo, Mariana; Chen, Eveline; Austin-Breneman, Jacob L.; Jiang, Hong; Roszik, Jason; Tetzlaff, Michael T.; Davies, Michael A.; Gershenwald, Jeffrey E.; Tawbi, Hussein; Lazar, Alexander J.; Hwu, Patrick; Hwu, Wen-Jen; Diab, Adi; Glitza, Isabella C.; Patel, Sapna P.; Woodman, Scott E.; Amaria, Rodabe N.; Prieto, Victor G.; Hu, Jianhua; Sharma, Padmanee; Allison, James P.; Chin, Lynda; Zhang, Jianhua; Wargo, Jennifer A.; Futreal, P. Andrew

2018-01-01

Immune checkpoint blockade produces clinical benefit in many patients. However better biomarkers of response are still needed, and mechanisms of resistance remain incompletely understood. To address this, we recently studied a cohort of melanoma patients treated with sequential checkpoint blockade against cytotoxic T lymphocyte antigen-4 (CTLA-4) followed by programmed death receptor-1 (PD-1), and identified immune markers of response and resistance. Building on these studies, we performed deep molecular profiling including T-cell receptor sequencing (TCR-seq) and whole exome sequencing (WES) within the same cohort, and demonstrated that a more clonal T cell repertoire was predictive of response to PD-1 but not CTLA-4 blockade. Analysis of copy number alterations identified a higher burden of copy number loss in non-responders to CTLA-4 and PD-1 blockade and found that it was associated with decreased expression of genes in immune-related pathways. The effect of mutational load and burden of copy number loss on response was non-redundant, suggesting the potential utility of a combinatorial biomarker to optimize patient care with checkpoint blockade therapy. PMID:28251903

Normotensive sodium loading in normal man: Regulation of renin secretion during beta-receptor blockade

DEFF Research Database (Denmark)

Mølstrøm, Simon; Larsen, Nils Heden; Simonsen, Jane Angel

2008-01-01

and renal excretion during slow saline loading at constant plasma sodium con-centration (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......Saline administration may change renin 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......-loading decreased plasma renin (PRC) by 1/3, AngII by 1/2, and aldosterone (pAldo) by 2/3, (all psodium excretion increased indistinguishably with and without metoprolol (16+/-2 to 71...

Review article: clinical implications of enteric and central D2 receptor blockade by antidopaminergic gastrointestinal prokinetics.

Science.gov (United States)

Tonini, M; Cipollina, L; Poluzzi, E; Crema, F; Corazza, G R; De Ponti, F

2004-02-15

Antidopaminergic gastrointestinal prokinetics (bromopride, clebopride, domperidone, levosulpiride and metoclopramide) have been exploited clinically for the management of motor disorders of the upper gastrointestinal tract, including functional dyspepsia, gastric stasis of various origins and emesis. The prokinetic effect of these drugs is mediated through the blockade of enteric (neuronal and muscular) inhibitory D2 receptors. The pharmacological profiles of the marketed compounds differ in terms of their molecular structure, affinity at D2 receptors, ability to interact with other receptor systems [5-hydroxytryptamine-3 (5-HT3) and 5-HT4 receptors for metoclopramide; 5-HT4 receptors for levosulpiride) and ability to permeate the blood-brain barrier (compared with the other compounds, domperidone does not easily cross the barrier). It has been suggested that the serotonergic (5-HT4) component of some antidopaminergic prokinetics may enhance their therapeutic efficacy in gastrointestinal disorders, such as functional dyspepsia and diabetic gastroparesis. The antagonism of central D2 receptors may lead to both therapeutic (e.g. anti-emetic effect due to D2 receptor blockade in the area postrema) and adverse (including hyperprolactinaemia and extrapyramidal dystonic reactions) effects. As the pituitary (as well as the area postrema) is outside the blood-brain barrier, hyperprolactinaemia is a side-effect occurring with all antidopaminergic prokinetics, although to different extents. Extrapyramidal reactions are most commonly observed with compounds crossing the blood-brain barrier, although with some differences amongst the various agents. Prokinetics with a high dissociation constant compared with that of dopamine at the D2 receptor (i.e. compounds that bind loosely to D2 receptors in the nigrostriatal pathway) elicit fewer extrapyramidal signs and symptoms. A knowledge of central and peripheral D2 receptor pharmacology can help the clinician to choose between the

Pharmacological Blockade of Adenosine A2A but Not A1 Receptors Enhances Goal-Directed Valuation in Satiety-Based Instrumental Behavior

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Yan Li

2018-04-01

Full Text Available The balance and smooth shift between flexible, goal-directed behaviors and repetitive, habitual actions are critical to optimal performance of behavioral tasks. The striatum plays an essential role in control of goal-directed versus habitual behaviors through a rich interplay of the numerous neurotransmitters and neuromodulators to modify the input, processing and output functions of the striatum. The adenosine receptors (namely A2AR and A1R, with their high expression pattern in the striatum and abilities to interact and integrate dopamine, glutamate and cannabinoid signals in the striatum, may represent novel therapeutic targets for modulating instrumental behavior. In this study, we examined the effects of pharmacological blockade of the A2ARs and A1Rs on goal-directed versus habitual behaviors in different information processing phases of instrumental learning using a satiety-based instrumental behavior procedure. We found that A2AR antagonist acts at the coding, consolidation and expression phases of instrumental learning to modulate animals’ sensitivity to goal-directed valuation without modifying action-outcome contingency. However, pharmacological blockade and genetic knockout of A1Rs did not affect acquisition or sensitivity to goal-valuation of instrumental behavior. These findings provide pharmacological evidence for a potential therapeutic strategy to control abnormal instrumental behaviors associated with drug addiction and obsessive-compulsive disorder by targeting the A2AR.

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

International Nuclear Information System (INIS)

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 [ 3 H]yohimbine, whereas [ 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, [ 3 H] clonidine and [ 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 [ 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

Systemic MCP1/CCR2 blockade and leukocyte specific MCP1/CCR2 inhibition affect aortic aneurysm formation differently

NARCIS (Netherlands)

de Waard, Vivian; Bot, Ilze; de Jager, Saskia C. A.; Talib, Sara; Egashira, Kensuke; de Vries, Margreet R.; Quax, Paul H. A.; Biessen, Erik A. L.; van Berkel, Theo J. C.

2010-01-01

Objective: CCR2, the receptor for monocyte chemoattractant protein 1 (MCP1), is involved in atherosclerosis and abdominal aortic aneurysms (AAAs). Here, we explored the potential beneficial blockade of the MCP1/CCR2 pathway. Methods: We applied an AAA model in aging apolipoprotein E deficient mice

Combined blockade of angiotensin II and prorenin receptors ameliorates podocytic apoptosis induced by IgA-activated mesangial cells.

Science.gov (United States)

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.

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

International Nuclear Information System (INIS)

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

2011-01-01

Highlights: → Lysophosphatidic acid (LPA) levels and its receptors LPAR1/3 transcripts were elevated during the development of radiation-induced lung fibrosis. → Lung fibrosis was obviously alleviated in mice treated with the dual LPAR1/3 antagonist, VPC12249. → VPC12249 administration effectively inhibited radiation-induced fibroblast accumulation in vivo, and suppressed LPA-induced fibroblast proliferation in vitro. → LPA-LPAR1/3 signaling regulated TGFβ1 and CTGF expressions in radiation-challenged lungs, but only influenced CTGF expression in cultured fibroblasts. → LPA-LPAR1/3 signaling induced fibroblast proliferation through a CTGF-dependent pathway, rather than through TGFβ1 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 β1 (TGFβ1) 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-LPAR1/3 signaling system is involved in the

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

Energy Technology Data Exchange (ETDEWEB)

Gan, Lu [State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu (China); Xue, Jian-Xin [Department of Thoracic Oncology, Cancer Center, West China Hospital, Sichuan University, Chengdu (China); Laboratory of Stem Cell Biology, West China Hospital, Sichuan University, Chengdu (China); Li, Xin [Department of Thoracic Oncology, Cancer Center, West China Hospital, Sichuan University, Chengdu (China); Liu, De-Song [Department of Pediatrics, Sichuan Provincial Hospital of Women and Children, Chengdu (China); Ge, Yan; Ni, Pei-Yan; Deng, Lin [State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu (China); Lu, You, E-mail: radyoulu@hotmail.com [State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu (China); Department of Thoracic Oncology, Cancer Center, West China Hospital, Sichuan University, Chengdu (China); Jiang, Wei, E-mail: wcumsjw72@hotmail.com [State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu (China); Molecular Medicine Research Center, West China Hospital, Sichuan University, Chengdu (China)

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

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

Science.gov (United States)

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 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. Copyright © 2015 the American Physiological Society.

Leptin receptor blockade reduces intrahepatic vascular resistance and portal pressure in an experimental model of rat liver cirrhosis.

Science.gov (United States)

Delgado, María Gabriela; Gracia-Sancho, Jordi; Marrone, Giusi; Rodríguez-Vilarrupla, Aina; Deulofeu, Ramon; Abraldes, Juan G; Bosch, Jaume; García-Pagán, Juan Carlos

2013-10-01

Increased hepatic vascular resistance mainly due to elevated vascular tone and to fibrosis is the primary factor in the development of portal hypertension in cirrhosis. Leptin, a hormone associated with reduction in nitric oxide bioavailability, vascular dysfunction, and liver fibrosis, is increased in patients with cirrhosis. We aimed at evaluating whether leptin influences the increased hepatic resistance in portal hypertension. CCl4-cirrhotic rats received the leptin receptor-blocker ObR antibody, or its vehicle, every other day for 1 wk. Hepatic and systemic hemodynamics were measured in both groups. Hepatic nitric oxide production and bioavailability, together with oxidative stress, nitrotyrosinated proteins, and liver fibrosis, were evaluated. In cirrhotic rats, leptin-receptor blockade significantly reduced portal pressure without modifying portal blood flow, suggesting a reduction in the intrahepatic resistance. Portal pressure reduction was associated with increased nitric oxide bioavailability and with decreased O2(-) levels and nitrotyrosinated proteins. No changes in systemic hemodynamics and liver fibrosis were observed. In conclusion, the present study shows that blockade of the leptin signaling pathway in cirrhosis significantly reduces portal pressure. This effect is probably due to a nitric oxide-mediated reduction in the hepatic vascular tone.

Blockade of AT1 receptors by losartan did not affect renin gene expression in kidney medulla

Czech Academy of Sciences Publication Activity Database

Tybitanclová, K.; Szabová, L.; Grima, M.; Ingert, C.; Železná, Blanka; Zórad, Š.

2006-01-01

Roč. 25, č. 1 (2006), s. 43-51 ISSN 0231-5882 Grant - others:VEGA(SK) 2/5090/25 Institutional research plan: CEZ:AV0Z50520514 Keywords : AT1 receptor * renin-angiotensin system * kidneys Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 0.771, year: 2006

Neurohumoral blockade in CHF management

Directory of Open Access Journals (Sweden)

Roland Willenbrock

2000-03-01

Full Text Available Is heart failure an endocrine disease? Historically, congestive heart failure (CHF has often been regarded as a mechanical and haemodynamic condition. However, there is now strong evidence that the activation of neuroendocrine systems, like the renin-angiotensin-aldosterone system (RAAS and sympathetic nervous system, as well as the activation of natriuretic peptides, endothelin and vasopressin, play key roles in the progression of CHF. In this context, agents targeting neurohormones offer a highly rational approach to CHF management, with ACE inhibitors, aldosterone antagonists and beta-adrenergic blockade improving the prognosis for many patients. Although relevant improvements in clinical status and survival can be achieved with these drug classes, mortality rates for patients with CHF are still very high. Moreover, most patients do not receive these proven life-prolonging drugs, partially due to fear of adverse events, such as hypotension (with ACE inhibitors, gynaecomastia (with spironolactone and fatigue (with beta-blockers.New agents that combine efficacy with better tolerability are therefore needed. The angiotensin II type 1 (AT1-receptor blockers have the potential to fulfil both these requirements, by blocking the deleterious cardiovascular and haemodynamic effects of angiotensin II while offering placebo-like tolerability. As shown with candesartan, AT1-receptor blockers also modulate the levels of other neurohormones, including aldosterone and atrial natriuretic peptide (ANP. Combined with its tight, long-lasting binding to AT1-receptors, this characteristic gives candesartan the potential for complete blockade of the RAAS-neurohormonal axis, along with the great potential to improve clinical outcomes.

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

Science.gov (United States)

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

THE EFFECTS OF ACUTE AND CHRONIC STRESS ON ERYTHROCYTE DYNAMIC IN COMBINATION WITH ß–ADRENERGIC RECEPTORS BLOCKADE IN RATS

Directory of Open Access Journals (Sweden)

Lucian Hritcu

2005-08-01

Full Text Available : 3 consecutive days propranolol hydrochloride administration (5 mg/kg b.w., subcutaneous injections under acute and chronic stress conditions causes changes of peripheral erythrocyte distribution in rats. The effects of acute stress and its combination with ȕ-adrenergic receptor blockade on erythrocyte dynamic were more pregnant beside the effects of chronic stress and its combination with ȕ-adrenergic receptor blockade, respectively. ȕ-adrenergic mechanisms were shown to be involved in regulation of erythrocyte dynamic in acute and chronic stress response.

Hypocretin/Orexin regulation of dopamine signaling and cocaine self-administration is mediated predominantly by hypocretin receptor 1.

Science.gov (United States)

Prince, Courtney D; Rau, Andrew R; Yorgason, Jordan T; España, Rodrigo A

2015-01-21

Extensive evidence suggests that the hypocretins/orexins influence cocaine reinforcement and dopamine signaling via actions at hypocretin receptor 1. By comparison, the involvement of hypocretin receptor 2 in reward and reinforcement processes has received relatively little attention. Thus, although there is some evidence that hypocretin receptor 2 regulates intake of some drugs of abuse, it is currently unclear to what extent hypocretin receptor 2 participates in the regulation of dopamine signaling or cocaine self-administration, particularly under high effort conditions. To address this, we examined the effects of hypocretin receptor 1, and/or hypocretin receptor 2 blockade on dopamine signaling and cocaine reinforcement. We used in vivo fast scan cyclic voltammetry to test the effects of hypocretin antagonists on dopamine signaling in the nucleus accumbens core and a progressive ratio schedule to examine the effects of these antagonists on cocaine self-administration. Results demonstrate that blockade of either hypocretin receptor 1 or both hypocretin receptor 1 and 2 significantly reduces the effects of cocaine on dopamine signaling and decreases the motivation to take cocaine. In contrast, blockade of hypocretin receptor 2 alone had no significant effects on dopamine signaling or self-administration. These findings suggest a differential involvement of the two hypocretin receptors, with hypocretin receptor 1 appearing to be more involved than hypocretin receptor 2 in the regulation of dopamine signaling and cocaine self-administration. When considered with the existing literature, these data support the hypothesis that hypocretins exert a permissive influence on dopamine signaling and motivated behavior via preferential actions on hypocretin receptor 1.

PD-1/CTLA-4 Blockade Inhibits Epstein-Barr Virus-Induced Lymphoma Growth in a Cord Blood Humanized-Mouse Model.

Directory of Open Access Journals (Sweden)

Shi-Dong Ma

2016-05-01

Full Text Available Epstein-Barr virus (EBV infection causes B cell lymphomas in humanized mouse models and contributes to a variety of different types of human lymphomas. T cells directed against viral antigens play a critical role in controlling EBV infection, and EBV-positive lymphomas are particularly common in immunocompromised hosts. We previously showed that EBV induces B cell lymphomas with high frequency in a cord blood-humanized mouse model in which EBV-infected human cord blood is injected intraperitoneally into NOD/LtSz-scid/IL2Rγnull (NSG mice. Since our former studies showed that it is possible for T cells to control the tumors in another NSG mouse model engrafted with both human fetal CD34+ cells and human thymus and liver, here we investigated whether monoclonal antibodies that block the T cell inhibitory receptors, PD-1 and CTLA-4, enhance the ability of cord blood T cells to control the outgrowth of EBV-induced lymphomas in the cord-blood humanized mouse model. We demonstrate that EBV-infected lymphoma cells in this model express both the PD-L1 and PD-L2 inhibitory ligands for the PD-1 receptor, and that T cells express the PD-1 and CTLA-4 receptors. Furthermore, we show that the combination of CTLA-4 and PD-1 blockade strikingly reduces the size of lymphomas induced by a lytic EBV strain (M81 in this model, and that this anti-tumor effect requires T cells. PD-1/CTLA-4 blockade markedly increases EBV-specific T cell responses, and is associated with enhanced tumor infiltration by CD4+ and CD8+ T cells. In addition, PD-1/CTLA-4 blockade decreases the number of both latently, and lytically, EBV-infected B cells. These results indicate that PD-1/CTLA-4 blockade enhances the ability of cord blood T cells to control outgrowth of EBV-induced lymphomas, and suggest that PD-1/CTLA-4 blockade might be useful for treating certain EBV-induced diseases in humans.

No effect of angiotensin II AT(2)-receptor antagonist PD 123319 on cerebral blood flow autoregulation

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Estrup, T M; Paulson, O B; Strandgaard, S

2001-01-01

Blockade of the renin-angiotensin system with angiotensin-converting enzyme inhibitors (ACE-I) or angiotensin AT1-receptor antagonists shift the limits of autoregulation of cerebral blood flow (CBF) towards lower blood pressure (BP). The role of AT2-receptors in the regulation of the cerebral cir...

Blockade of central nicotine acetylcholine receptor signaling attenuate ghrelin-induced food intake in rodents.

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Dickson, S L; Hrabovszky, E; Hansson, C; Jerlhag, E; Alvarez-Crespo, M; Skibicka, K P; Molnar, C S; Liposits, Z; Engel, J A; Egecioglu, E

2010-12-29

Here we sought to determine whether ghrelin's central effects on food intake can be interrupted by nicotine acetylcholine receptor (nAChR) blockade. Ghrelin regulates mesolimbic dopamine neurons projecting from the ventral tegmental area (VTA) to the nucleus accumbens, partly via cholinergic VTA afferents originating in the laterodorsal tegmental area (LDTg). Given that these cholinergic projections to the VTA have been implicated in natural as well as drug-induced reinforcement, we sought to investigate the role of cholinergic signaling in ghrelin-induced food intake as well as fasting-induced food intake, for which endogenous ghrelin has been implicated. We found that i.p. treatment with the non-selective centrally active nAChR antagonist, mecamylamine decreased fasting-induced food intake in both mice and rats. Moreover, central administration of mecamylamine decreased fasting-induced food intake in rats. I.c.v. ghrelin-induced food intake was suppressed by mecamylamine i.p. but not by hexamethonium i.p., a peripheral nAChR antagonist. Furthermore, mecamylamine i.p. blocked food intake following ghrelin injection into the VTA. Expression of the ghrelin receptor, the growth hormone secretagogue receptor 1A, was found to co-localize with choline acetyltransferase, a marker of cholinergic neurons, in the LDTg. Finally, mecamylamine treatment i.p. decreased the ability of palatable food to condition a place preference. These data suggest that ghrelin-induced food intake is partly mediated via nAChRs and that nicotinic blockade decreases the rewarding properties of food. Copyright © 2010 IBRO. Published by Elsevier Ltd. All rights reserved.

NMDA-receptor blockade by CPP impairs post-training consolidation of a rapidly acquired spatial representation in rat hippocampus.

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McDonald, Robert J; Hong, Nancy S; Craig, Laura A; Holahan, Matthew R; Louis, Meira; Muller, Robert U

2005-09-01

Recent evidence suggests that N-methyl-D-aspartate (NMDA)-receptor mediated plasticity in hippocampus has a more subtle role in memory-based behaviours than originally thought. One idea is that NMDA-based plasticity is essential for the consolidation of post-training memory but not for the initial encoding or for short-term memory. To further test this idea we used a three-phase variant of the hidden goal water maze task. In the first phase, rats were pre-trained to an initial location. Next, intense, massed training was done in a 2-h interval to teach the rats to go to a new location after either an injection of the NMDA receptor antagonist (6)-3-(2-carboxypiperazin-4-yl)propyl-1-phosphonic acid (CPP) or of vehicle. Finally, under drug-free conditions 24 h after new location training, a competition test was done between the original and new locations. We find that N-methyl-D-aspartate (NMDA)-receptor blockade has little or no effect on new location training. In contrast, when tested 24 h later, the strength of the trace for the new location learned during NMDA-receptor blockade was much weaker compared with the trace for the new location learned after saline injection. Further experiments showed similar effects when NMDA-receptors were blocked immediately after the new location training, suggesting that this is a memory consolidation effect. Our results therefore reinforce the notion that hippocampal NMDA-receptors participate in post-training memory consolidation but are not essential for the processes necessary to learn or retain navigational information in the short term.

Systemic blockade of D2-like dopamine receptors facilitates extinction of conditioned fear in mice

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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 that blockade of D2 receptors might facilitate extinction in mice, while agonists should block extinction, as they do in rats. One day after fear con...

Angiotensin receptor blockade improves cardiac mitochondrial activity in response to an acute glucose load in obese insulin resistant rats

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Max Thorwald

2018-04-01

Full Text Available Hyperglycemia increases the risk of oxidant overproduction in the heart through activation of a multitude of pathways. Oxidation of mitochondrial enzymes may impair their function resulting in accumulation of intermediates and reverse electron transfer, contributing to mitochondrial dysfunction. Furthermore, the renin-angiotensin system (RAS becomes inappropriately activated during metabolic syndrome, increasing oxidant production. To combat excess oxidant production, the transcription factor, nuclear factor erythriod-2- related factor 2 (Nrf2, induces expression of many antioxidant genes. We hypothesized that angiotensin II receptor type 1 (AT1 blockade improves mitochondrial function in response to an acute glucose load via upregulation of Nrf2. To address this hypothesis, an oral glucose challenge was performed in three groups prior to dissection (n = 5–8 animals/group/time point of adult male rats: 1 Long Evans Tokushima Otsuka (LETO; lean strain-control, 2 insulin resistant, obese Otsuka Long Evans Tokushima Fatty (OLETF, and 3 OLETF + angiotensin receptor blocker (ARB; 10 mg olmesartan/kg/d × 6 weeks. Hearts were collected at T0, T60, and T120 minutes post-glucose infusion. ARB increased Nrf2 binding 32% compared to OLETF at T60. Total superoxide dismutase (SOD and catalase (CAT activities were increased 45% and 66% respectively in ARB treated animals compared to OLETF. Mitochondrial enzyme activities of aconitase, complex I, and complex II increased by 135%, 33% and 66%, respectively in ARB compared to OLETF. These data demonstrate the protective effects of AT1 blockade on mitochondrial function during the manifestation of insulin resistance suggesting that the inappropriate activation of AT1 during insulin resistance may impair Nrf2 translocation and subsequent antioxidant activities and mitochondrial function. Keywords: Angiotensin II, Mitochondria, Cardiac, Antioxidant enzymes, TCA cycle

Dual Mechanism of Interleukin-3 Receptor Blockade by an Anti-Cancer Antibody

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Sophie E. Broughton

2014-07-01

Full Text Available Interleukin-3 (IL-3 is an activated T cell product that bridges innate and adaptive immunity and contributes to several immunopathologies. Here, we report the crystal structure of the IL-3 receptor α chain (IL3Rα in complex with the anti-leukemia antibody CSL362 that reveals the N-terminal domain (NTD, a domain also present in the granulocyte-macrophage colony-stimulating factor (GM-CSF, IL-5, and IL-13 receptors, adopting unique “open” and classical “closed” conformations. Although extensive mutational analyses of the NTD epitope of CSL362 show minor overlap with the IL-3 binding site, CSL362 only inhibits IL-3 binding to the closed conformation, indicating alternative mechanisms for blocking IL-3 signaling. Significantly, whereas “open-like” IL3Rα mutants can simultaneously bind IL-3 and CSL362, CSL362 still prevents the assembly of a higher-order IL-3 receptor-signaling complex. The discovery of open forms of cytokine receptors provides the framework for development of potent antibodies that can achieve a “double hit” cytokine receptor blockade.

Adenosine A2A receptor blockade Prevents Rotenone-Induced Motor Impairment in a Rat Model of Parkinsonism

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Ahmed M Fathalla

2016-02-01

Full Text Available 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 A2Aand 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. 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 high performance liquid chromatography. The effect of rotenone was partially preventedin the ZM241385 group, but not with 8-cyclopentyl-1,3-dipropylxanthine administration. The administration of ZM241385 has led toan improvement improved of motor function and movement coordination (a 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 A2Areceptor blockade by ZM241385, but not A1receptor 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.. This may provide a more selective treatment strategy for PD patients.

VEGF receptor blockade markedly reduces retinal microglia/macrophage infiltration into laser-induced CNV.

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Hu Huang

Full Text Available Although blocking VEGF has a positive effect in wet age-related macular degeneration (AMD, the effect of blocking its receptors remains unclear. This was an investigation of the effect of VEGF receptor (VEGFR 1 and/or 2 blockade on retinal microglia/macrophage infiltration in laser-induced choroidal neovascularization (CNV, a model of wet AMD. CNV lesions were isolated by laser capture microdissection at 3, 7, and 14 days after laser and analyzed by RT-PCR and immunofluorescence staining for mRNA and protein expression, respectively. Neutralizing antibodies for VEGFR1 or R2 and the microglia inhibitor minocycline were injected intraperitoneally (IP. Anti-CD11b, CD45 and Iba1 antibodies were used to confirm the cell identity of retinal microglia/macrophage, in the RPE/choroidal flat mounts or retinal cross sections. CD11b(+, CD45(+ or Iba1(+ cells were counted. mRNA of VEGFR1 and its three ligands, PlGF, VEGF-A (VEGF and VEGF-B, were expressed at all stages, but VEGFR2 were detected only in the late stage. PlGF and VEGF proteins were expressed at 3 and 7 days after laser. Anti-VEGFR1 (MF1 delivered IP 3 days after laser inhibited infiltration of leukocyte populations, largely retinal microglia/macrophage to CNV, while anti-VEGFR2 (DC101 had no effect. At 14 days after laser, both MF1 and DC101 antibodies markedly inhibited retinal microglia/macrophage infiltration into CNV. Therefore, VEGFR1 and R2 play differential roles in the pathogenesis of CNV: VEGFR1 plays a dominant role at 3 days after laser; but both receptors play pivotal roles at 14 days after laser. In vivo imaging demonstrated accumulation of GFP-expressing microglia into CNV in both CX3CR1(gfp/gfp and CX3CR1(gfp/+ mice. Minocycline treatment caused a significant increase in lectin(+ cells in the sub-retinal space anterior to CNV and a decrease in dextran-perfused neovessels compared to controls. Targeting the chemoattractant molecules that regulate trafficking of retinal microglia

Effects of Mineralocorticoid Receptors Blockade on FearMemory Reconsolidation in Rats

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Abbas Ali Vafaei

2011-08-01

Full Text Available Reconsolidation memory is defined as a process in which the retrieval of a previously consolidated memory returns to a labile state which is then subject to stabilization. Previous studies have shown that mineralocorticoid receptors (MRs modulate distinct phases of learning and memory, which display a high concentration and distinct distribution in the hippocampus. Moreover, we found no studies that examined the role of hippocampal MRs in fear memory reconsolidation. Here, we investigated the effect of MRs blockade on fear memory reconsolidation in rats. Additionally, to test whether blockade of protein synthesis would disrupt fear memory reconsolidation in our paradigm, we tested the effect of cycloheximide, an inhibitor of protein synthesis after memory reactivation. Results indicated that systemic as well as intra-hippocampal administrations of the MR antagonist spironolactone immediately following memory reactivation did not affect on post-retrieval long-term memory. Cycloheximide given after the reactivation treatment produced a strong impairment that persisted over test sessions. These findings indicate that MRs are not required for reconsolidation of fear-based memory.

Blockade of cannabinoid CB receptor function protects against in vivo disseminating brain damage following NMDA-induced excitotoxicity

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Hansen, H.H.; Ramos, J.A.; Fernández-Ruiz, J.

2002-01-01

-induced excitotoxic damage in the ipsilateral forebrain was not influenced by agonist-stimulated CB receptor function. In contrast, blockade of CB, but not CB, receptor activity evoked a robust neuroprotective response by reducing the infarct area and the number of cortical degenerating neurons. These results suggest...... receptor function on NMDA-induced excitotoxicity. Neonatal (6-day-old) rat pups received a systemic injection of a mixed CB/CB receptor agonist (WIN55,212-2) or their respective antagonists (SR141716A for CB and SR144528 for CB) prior to an unilateral intrastriatal microinjection of NMDA. The NMDA...... a critical involvement of CB receptor tonus on neuronal survival following NMDA receptor-induced excitotoxicity in vivo....

Blockade of Cannabinoid CB1 Receptors in the Dorsal Periaqueductal Gray Unmasks the Antinociceptive Effect of Local Injections of Anandamide in Mice

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Diego C. Mascarenhas

2017-10-01

Full Text Available Divergent results in pain management account for the growing number of studies aiming at elucidating the pharmacology of the endocannabinoid/endovanilloid anandamide (AEA within several pain-related brain structures. For instance, the stimulation of both Transient Receptor Potential Vanilloid type 1 (TRPV1 and Cannabinoid type 1 (CB1 receptors led to paradoxical effects on nociception. Here, we attempted to propose a clear and reproducible methodology to achieve the antinociceptive effect of exogenous AEA within the dorsal periaqueductal gray (dPAG of mice exposed to the tail-flick test. Accordingly, male Swiss mice received intra-dPAG injection of AEA (CB1/TRPV1 agonist, capsaicin (TRPV1 agonist, WIN (CB1 agonist, AM251 (CB1 antagonist, and 6-iodonordihydrocapsaicin (6-IODO (TRPV1 selective antagonist and their nociceptive response was assessed with the tail-flick test. In order to assess AEA effects on nociception specifically at vanilloid or cannabinoid (CB substrates into the dPAG, mice underwent an intrinsically inactive dose of AM251 or 6-IODO followed by local AEA injections and were subjected to the same test. While intra-dPAG AEA did not change acute pain, local injections of capsaicin or WIN induced a marked TRPV1- and CB1-dependent antinociceptive effect, respectively. Regarding the role of AEA specifically at CB/vanilloid substrates, while the blockade of TRPV1 did not change the lack of effects of intra-dPAG AEA on nociception, local pre-treatment of AM251, a CB1 antagonist, led to a clear AEA-induced antinociception. It seems that the exogenous AEA-induced antinociception is unmasked when it selectively binds to vanilloid substrates, which might be useful to address acute pain in basic and perhaps clinical trials.

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

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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.

Timing of CSF-1/CSF-1R signaling blockade is critical to improving responses to CTLA-4 based immunotherapy

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Holmgaard, Rikke B.; Brachfeld, Alexandra; Gasmi, Billel; Jones, David R.; Mattar, Marissa; Doman, Thompson; Murphy, Mary; Schaer, David; Wolchok, Jedd D.; Merghoub, Taha

2016-01-01

ABSTRACT Colony stimulating factor-1 (CSF-1) is produced by a variety of cancers and recruits myeloid cells that suppress antitumor immunity, including myeloid-derived suppressor cells (MDSCs.) Here, we show that both CSF-1 and its receptor (CSF-1R) are frequently expressed in tumors from cancer patients, and that this expression correlates with tumor-infiltration of MDSCs. Furthermore, we demonstrate that these tumor-infiltrating MDSCs are highly immunosuppressive but can be reprogrammed toward an antitumor phenotype in vitro upon CSF-1/CSF-1R signaling blockade. Supporting these findings, we show that inhibition of CSF-1/CSF-1R signaling using an anti-CSF-1R antibody can regulate both the number and the function of MDSCs in murine tumors in vivo. We further find that treatment with anti-CSF-1R antibody induces antitumor T-cell responses and tumor regression in multiple tumor models when combined with CTLA-4 blockade therapy. However, this occurs only when administered after or concurrent with CTLA-4 blockade, indicating that timing of each therapeutic intervention is critical for optimal antitumor responses. Importantly, MDSCs present within murine tumors after CTLA-4 blockade showed increased expression of CSF-1R and were capable of suppressing T cell proliferation, and CSF-1/CSF-1R expression in the human tumors was not reduced after treatment with CTLA-4 blockade immunotherapy. Taken together, our findings suggest that CSF-1R-expressing MDSCs can be targeted to modulate the tumor microenvironment and that timing of CSF-1/CSF-1R signaling blockade is critical to improving responses to checkpoint based immunotherapy. Significance: Infiltration by immunosuppressive myeloid cells contributes to tumor immune escape and can render patients resistant or less responsive to therapeutic intervention with checkpoint blocking antibodies. Our data demonstrate that blocking CSF-1/CSF-1R signaling using a monoclonal antibody directed to CSF-1R can regulate both the number

Blockade of serotonin 5-HT2A receptors potentiates dopamine D2 activation-induced disruption of pup retrieval on an elevated plus maze, but has no effect on D2 blockade-induced one.

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Nie, Lina; Di, Tianqi; Li, Yu; Cheng, Peng; Li, Ming; Gao, Jun

2018-06-23

Appetitive aspect of rat maternal behavior, such as pup retrieval, is motivationally driven and sensitive to dopamine disturbances. Activation or blockade of dopamine D 2 receptors causes a similar disruption of pup retrieval, which may also reflect an increase in maternal anxiety and/or a disruption of executive function. Recent work indicates that serotonin 5-HT 2A receptors also play an important role in rat maternal behavior. Given the well-known modulation of 5-HT 2A on the mesolimbic and mesocortical dopamine functions, the present study examined the extent to which blockade of 5-HT 2A receptors on dopamine D 2 -mediated maternal effects using a pup retrieval on the elevated plus maze (EPM) test. Sprague-Dawley postpartum female rats were acutely injected with quinpirole (a D 2 agonist, 0.10 and 0.25 mg/kg, sc), or haloperidol (a D 2 antagonist, 0.1 or 0.2 mg/kg, sc), in combination of MDL100907 (a 5-HT 2A receptor antagonist, 1.0 mg/kg, sc, 30 min before quinpirole or haloperidol injection) or saline and tested at 30, 90 and 240 min after quinpirole or haloperidol injection on postpartum days 3 and 7. Quinpirole and haloperidol decreased the number of pup retrieved (an index of maternal motivation) and sequential retrieval score (an index of executive function), prolonged the pup retrieval latencies, reduced the percentage of time spent on the open arms (an index of maternal anxiety), and decreased the distance travelled on the maze in a dose-dependent and time-dependent fashion. MDL100907 treatment by itself had no effect on pup retrieval, but it exacerbated the quinpirole-induced disruption of pup retrieval, but had no effect on the haloperidol-induced one. These findings suggest a complex interactive effect between 5-HT 2A and D 2 receptors on one or several maternal processes (maternal motivation, anxiety and executive function), and support the idea that one molecular mechanism by which 5-HT 2A receptors mediate maternal behavior is through

Benzazepines: Structure-activity relationships between D1 receptor blockade and selected pharmacological effects

International Nuclear Information System (INIS)

Iorio, L.C.; Billiard, W.; Gold, E.H.

1986-01-01

This chapter describes the displacement of 3 H-23390 and 3 H-spiperone binding by dopamine agonists and antagonists. The authors undertook an evaluation of the ability of selected analogs of SCH 23390 to displace 3 H-SCH 23390 and 3 H-spiperone. Structure-activity relationships of SCH 23390 analogs: 7-position substituents, is shown. It is shown that, in general, benzazepines with a variety of substituents in the 7-position retain their selectivity for D 1 sites. Substituents at the 8-position and at the N-position are also discussed. The authors determine a correlation between displacement of 3 H-SCH 23390 and blockade of dopamine-sensitive adenylate cyclase (DSAC). These effects and inhibition of conditioned avoidance responsing (CAS) in rats was also studied. A detailed evaluation is presented of the effects of SCH 23390 and haloperidol in the Inclined Screen and CAR tests

Pindolol antagonises G-protein activation at both pre- and postsynaptic serotonin 5-HT1A receptors: a.

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Newman-Tancredi, A; Chaput, C; Touzard, M; Millan, M J

2001-04-01

The arylalkylamine, pindolol, may potentiate the clinical actions of antidepressant agents. Although it is thought to act via blockade of 5-HT1A autoreceptors, its efficacy at these sites remains controversial. Herein, we evaluated the actions of pindolol at 5-HT1A autoreceptors and specific populations of postsynaptic 5-HT1A receptors employing [35S]GTPgammaS autoradiography, a measure of receptor-mediated G-protein activation. Both 8-OH-DPAT (1 microM) and 5-HT (10 microM) elicited a pronounced increase in [35S]GTPyS binding in the dorsal raphe nucleus, which contains serotonergic cell bodies bearing 5-HT1A autoreceptors. Pindolol abolished their actions. In the dentate gyrus, lateral septum and entorhinal cortex, structures enriched in postsynaptic 5-HT1A receptors, 8-OH-DPAT (1 microM) and 5-HT (10 microM) also elicited a marked increase in [35S]GTPgammaS binding which was likewise blocked by pindolol. The antagonism of 5-HT-induced [35S]GTPgammaS labelling in the dentate gyrus was shown to be concentration-dependent, yielding a pIC50 of 5.82. Pindolol did not, itself, affect [35S]GTPgammaS binding in any brain region examined. In conclusion, these data suggest that, as characterised by [35S]GTPgammaS autoradiography, and compared with 5-HT and 8-OH-DPAT, pindolol possesses low efficacy at both pre- and postsynaptic 5-HT1A receptors.

Endocannabinoid receptor 1 gene variations increase risk for obesity and modulate body mass index in European populations

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Benzinou, Michael; Chèvre, Jean-Claude; Ward, Kirsten J

2008-01-01

The therapeutic effects of cannabinoid receptor blockade on obesity-associated phenotypes underline the importance of the endocannabinoid pathway on the energy balance. Using a staged-approach, we examined the contribution of the endocannabinoid receptor 1 gene (CNR1) on obesity and body mass ind...... variations increase the risk for obesity and modulate BMI in our European population. As CB1 is a drug target for obesity, a pharmacogenetic analysis of the endocannabinoid blockade obesity treatment may be of interest to identify best responders....

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

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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.

A randomized trial on mineralocorticoid receptor blockade in men: effects on stress responses, selective attention, and memory.

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Cornelisse, Sandra; Joëls, Marian; Smeets, Tom

2011-12-01

Corticosteroids, released in high amounts after stress, exert their effects via two different receptors in the brain: glucocorticoid receptors (GRs) and mineralocorticoid receptors (MRs). GRs have a role in normalizing stress-induced effects and promoting consolidation, while MRs are thought to be important in determining the threshold for activation of the hypothalamic-pituitary-adrenal (HPA) axis. We investigated the effects of MR blockade on HPA axis responses to stress and stress-induced changes in cognitive function. In a double-blind, placebo-controlled study, 64 healthy young men received 400 mg of the MR antagonist spironolactone or placebo. After 1.5 h, they were exposed to either a Trier Social Stress Test or a non-stressful control task. Responses to stress were evaluated by hormonal, subjective, and physiological measurements. Afterwards, selective attention, working memory, and long-term memory performance were assessed. Spironolactone increased basal salivary cortisol levels as well as cortisol levels in response to stress. Furthermore, spironolactone significantly impaired selective attention, but only in the control group. The stress group receiving spironolactone showed impaired working memory performance. By contrast, long-term memory was enhanced in this group. These data support a role of MRs in the regulation of the HPA axis under basal conditions as well as in response to stress. The increased availability of cortisol after spironolactone treatment implies enhanced GR activation, which, in combination with MR blockade, presumably resulted in a decreased MR/GR activation ratio. This condition influences both selective attention and performance in various memory tasks.

Remodeling of intrinsic cardiac neurons: effects of β-adrenergic receptor blockade in guinea pig models of chronic heart disease.

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Hardwick, Jean C; Southerland, E Marie; Girasole, Allison E; Ryan, Shannon E; Negrotto, Sara; Ardell, Jeffrey L

2012-11-01

Chronic heart disease induces remodeling of cardiac tissue and associated neuronal components. Treatment of chronic heart disease often involves pharmacological blockade of adrenergic receptors. This study examined the specific changes in neuronal sensitivity of guinea pig intrinsic cardiac neurons to autonomic modulators in animals with chronic cardiac disease, in the presence or absence of adrenergic blockage. Myocardial infarction (MI) was produced by ligature of the coronary artery and associated vein on the dorsal surface of the heart. Pressure overload (PO) was induced by a banding of the descending dorsal aorta (∼20% constriction). Animals were allowed to recover for 2 wk and then implanted with an osmotic pump (Alzet) containing either timolol (2 mg·kg(-1)·day(-1)) or vehicle, for a total of 6-7 wk of drug treatment. At termination, intracellular recordings from individual neurons in whole mounts of the cardiac plexus were used to assess changes in physiological responses. Timolol treatment did not inhibit the increased sensitivity to norepinephrine seen in both MI and PO animals, but it did inhibit the stimulatory effects of angiotensin II on the norepinephrine-induced increases in neuronal excitability. Timolol treatment also inhibited the increase in synaptically evoked action potentials observed in PO animals with stimulation of fiber tract bundles. These results demonstrate that β-adrenergic blockade can inhibit specific aspects of remodeling within the intrinsic cardiac plexus. In addition, this effect was preferentially observed with active cardiac disease states, indicating that the β-receptors were more influential on remodeling during dynamic disease progression.

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

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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.

Glucagon and plasma catecholamines during beta-receptor blockade in exercising man

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Galbo, H; Holst, Janett; Christensen, N J

1976-01-01

Seven men ran at 60% of individual maximal oxygen uptake to exhaustion during beta-adrenergic blockade with propranolol (P), during lipolytic blockade with nicotinic acid (N), or without drugs (C). The total work times (83 +/- 9 (P), 122 +/- 8 (N), 166 +/- 10 (C) min, mean and SE) differed signif...... determinants for the exercise-induced glucagon secretion in man. It is suggested that decreased glucose availability enhances the secretion of glucagon and epinephrine during prolonged exercise....

The effect of α1 -adrenergic blockade on post-exercise brachial artery flow-mediated dilatation at sea level and high altitude.

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Tymko, Michael M; Tremblay, Joshua C; Hansen, Alex B; Howe, Connor A; Willie, Chris K; Stembridge, Mike; Green, Daniel J; Hoiland, Ryan L; Subedi, Prajan; Anholm, James D; Ainslie, Philip N

2017-03-01

Our objective was to quantify endothelial function (via brachial artery flow-mediated dilatation) at sea level (344 m) and high altitude (3800 m) at rest and following both maximal exercise and 30 min of moderate-intensity cycling exercise with and without administration of an α 1 -adrenergic blockade. Brachial endothelial function did not differ between sea level and high altitude at rest, nor following maximal exercise. At sea level, endothelial function decreased following 30 min of moderate-intensity exercise, and this decrease was abolished with α 1 -adrenergic blockade. At high altitude, endothelial function did not decrease immediately after 30 min of moderate-intensity exercise, and administration of α 1 -adrenergic blockade resulted in an increase in flow-mediated dilatation. Our data indicate that post-exercise endothelial function is modified at high altitude (i.e. prolonged hypoxaemia). The current study helps to elucidate the physiological mechanisms associated with high-altitude acclimatization, and provides insight into the relationship between sympathetic nervous activity and vascular endothelial function. We examined the hypotheses that (1) at rest, endothelial function would be impaired at high altitude compared to sea level, (2) endothelial function would be reduced to a greater extent at sea level compared to high altitude after maximal exercise, and (3) reductions in endothelial function following moderate-intensity exercise at both sea level and high altitude are mediated via an α 1 -adrenergic pathway. In a double-blinded, counterbalanced, randomized and placebo-controlled design, nine healthy participants performed a maximal-exercise test, and two 30 min sessions of semi-recumbent cycling exercise at 50% peak output following either placebo or α 1 -adrenergic blockade (prazosin; 0.05 mg kg  -1 ). These experiments were completed at both sea-level (344 m) and high altitude (3800 m). Blood pressure (finger photoplethysmography

Blockade of alcohol's amnestic activity in humans by an alpha5 subtype benzodiazepine receptor inverse agonist.

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Nutt, David J; Besson, Marie; Wilson, Susan J; Dawson, Gerard R; Lingford-Hughes, Anne R

2007-12-01

Alcohol produces many subjective and objective effects in man including pleasure, sedation, anxiolysis, plus impaired eye movements and memory. In human volunteers we have used a newly available GABA-A/benzodiazepine receptor inverse agonist that is selective for the alpha5 subtype (a5IA) to evaluate the role of this subtype in mediating these effects of alcohol on the brain. After pre-treatment with a5IA, we found almost complete blockade of the marked impairment caused by alcohol (mean breath concentration 150mg/100ml) of word list learning and partial but non-significant reversal of subjective sedation without effects on other measures such as intoxication, liking, and slowing of eye movements. This action was not due to alterations in alcohol kinetics and so provides the first proof of concept that selectively decreasing GABA-A receptor function at a specific receptor subtype can offset some actions of alcohol in humans. It also supports growing evidence for a key role of the alpha5 subtype in memory. Inverse agonists at other GABA-A receptor subtypes may prove able to reverse other actions of alcohol, and so offer a new approach to understanding the actions of alcohol in the human brain and in the treatment of alcohol related disorders in humans.

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

International Nuclear Information System (INIS)

Wong, D.F.; Wagner, H.N. Jr.; Coyle, J.

1985-01-01

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

IGF-1 Receptor Differentially Regulates Spontaneous and Evoked Transmission via Mitochondria at Hippocampal Synapses

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Gazit, Neta; Vertkin, Irena; Shapira, Ilana; Helm, Martin; Slomowitz, Edden; Sheiba, Maayan; Mor, Yael; Rizzoli, Silvio; Slutsky, Inna

2016-01-01

Summary The insulin-like growth factor-1 receptor (IGF-1R) signaling is a key regulator of lifespan, growth, and development. While reduced IGF-1R signaling delays aging and Alzheimer’s disease progression, whether and how it regulates information processing at central synapses remains elusive. Here, we show that presynaptic IGF-1Rs are basally active, regulating synaptic vesicle release and short-term plasticity in excitatory hippocampal neurons. Acute IGF-1R blockade or transient knockdown suppresses spike-evoked synaptic transmission and presynaptic cytosolic Ca2+ transients, while promoting spontaneous transmission and resting Ca2+ level. This dual effect on transmitter release is mediated by mitochondria that attenuate Ca2+ buffering in the absence of spikes and decrease ATP production during spiking activity. We conclude that the mitochondria, activated by IGF-1R signaling, constitute a critical regulator of information processing in hippocampal neurons by maintaining evoked-to-spontaneous transmission ratio, while constraining synaptic facilitation at high frequencies. Excessive IGF-1R tone may contribute to hippocampal hyperactivity associated with Alzheimer’s disease. Video Abstract PMID:26804996

Interleukin-1 antagonists and other cytokine blockade strategies for type 1 diabetes

DEFF Research Database (Denmark)

Mandrup-Poulsen, Thomas

2012-01-01

Proinflammatory cytokines stimulate adaptive immunity and attenuate T cell regulation and tolerance induction. They also profoundly impair β-cell function, proliferation, and viability, activities of similar importance in the context of type 1 diabetes (T1D). Detailed knowledge of the molecular...... mechanisms of β-cell toxicity has been gathered within the last 2-3 decades. However, the efficacy of individual proinflammatory cytokine blockade in animal models of T1D has been inconsistent and generally modest, except in the context of islet transplantation. This suggests that the timing of the cytokine...... blockade relative to anti-β-cell immune activation is critical, and that combination therapy may be required. In randomized, placebo-controlled, clinical trials of limited power, TNF-α (but not IL-1) blockade has yielded moderate but significant improvements in glycemia, insulin requirement, and β...

The effect of α1‐adrenergic blockade on post‐exercise brachial artery flow‐mediated dilatation at sea level and high altitude

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Tremblay, Joshua C.; Hansen, Alex B.; Howe, Connor A.; Willie, Chris K.; Stembridge, Mike; Green, Daniel J.; Hoiland, Ryan L.; Subedi, Prajan; Anholm, James D.; Ainslie, Philip N.

2016-01-01

Key points Our objective was to quantify endothelial function (via brachial artery flow‐mediated dilatation) at sea level (344 m) and high altitude (3800 m) at rest and following both maximal exercise and 30 min of moderate‐intensity cycling exercise with and without administration of an α1‐adrenergic blockade.Brachial endothelial function did not differ between sea level and high altitude at rest, nor following maximal exercise.At sea level, endothelial function decreased following 30 min of moderate‐intensity exercise, and this decrease was abolished with α1‐adrenergic blockade. At high altitude, endothelial function did not decrease immediately after 30 min of moderate‐intensity exercise, and administration of α1‐adrenergic blockade resulted in an increase in flow‐mediated dilatation.Our data indicate that post‐exercise endothelial function is modified at high altitude (i.e. prolonged hypoxaemia). The current study helps to elucidate the physiological mechanisms associated with high‐altitude acclimatization, and provides insight into the relationship between sympathetic nervous activity and vascular endothelial function. Abstract We examined the hypotheses that (1) at rest, endothelial function would be impaired at high altitude compared to sea level, (2) endothelial function would be reduced to a greater extent at sea level compared to high altitude after maximal exercise, and (3) reductions in endothelial function following moderate‐intensity exercise at both sea level and high altitude are mediated via an α1‐adrenergic pathway. In a double‐blinded, counterbalanced, randomized and placebo‐controlled design, nine healthy participants performed a maximal‐exercise test, and two 30 min sessions of semi‐recumbent cycling exercise at 50% peak output following either placebo or α1‐adrenergic blockade (prazosin; 0.05 mg kg −1). These experiments were completed at both sea‐level (344 m) and high altitude (3800�

5-HT1A receptor blockade targeting the basolateral amygdala improved stress-induced impairment of memory consolidation and retrieval in rats.

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Sardari, M; Rezayof, A; Zarrindast, M-R

2015-08-06

The aim of the present study was to investigate the possible role of basolateral amygdala (BLA) 5-HT1A receptors in memory formation under stress. We also examined whether the blockade of these receptors is involved in stress-induced state-dependent memory. Adult male Wistar rats received cannula implants that bilaterally targeted the BLA. Long-term memory was examined using the step-through type of passive avoidance task. Behavioral stress was evoked by exposure to an elevated platform (EP) for 10, 20 and 30min. Post-training exposure to acute stress (30min) impaired the memory consolidation. In addition, pre-test exposure to acute stress-(20 and 30min) induced the impairment of memory retrieval. Interestingly, the memory impairment induced by post-training exposure to stress was restored in the animals that received 20- or 30-min pre-test stress exposure, suggesting stress-induced state-dependent memory retrieval. Post-training BLA-targeted injection of a selective 5-HT1A receptor antagonist, (S)-WAY-100135 (2μg/rat), prevented the impairing effect of stress on memory consolidation. Pre-test injection of the same doses of (S)-WAY-100135 that was targeted to the BLA also reversed stress-induced memory retrieval impairment. It should be considered that post-training or pre-test BLA-targeted injection of (S)-WAY-100135 (0.5-2μg/rat) by itself had no effect on the memory formation. Moreover, pre-test injection of (S)-WAY-100135 (2μg/rat) that targeted the BLA inhibited the stress-induced state-dependent memory retrieval. Taken together, our findings suggest that post-training or pre-test exposure to acute stress induced the impairment of memory consolidation, retrieval and state-dependent learning. The BLA 5-HT1A receptors have a critical role in learning and memory under stress. Copyright © 2015 IBRO. Published by Elsevier Ltd. All rights reserved.

Effects of activation and blockade of dopamine receptors on the extinction of a passive avoidance reaction in mice with a depressive-like state.

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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.

Incorporation of Immune Checkpoint Blockade into Chimeric Antigen Receptor T Cells (CAR-Ts): Combination or Built-In CAR-T.

Science.gov (United States)

Yoon, Dok Hyun; Osborn, Mark J; Tolar, Jakub; Kim, Chong Jai

2018-01-24

Chimeric antigen receptor (CAR) T cell therapy represents the first U.S. Food and Drug Administration approved gene therapy and these engineered cells function with unprecedented efficacy in the treatment of refractory CD19 positive hematologic malignancies. CAR translation to solid tumors is also being actively investigated; however, efficacy to date has been variable due to tumor-evolved mechanisms that inhibit local immune cell activity. To bolster the potency of CAR-T cells, modulation of the immunosuppressive tumor microenvironment with immune-checkpoint blockade is a promising strategy. The impact of this approach on hematological malignancies is in its infancy, and in this review we discuss CAR-T cells and their synergy with immune-checkpoint blockade.

Incorporation of Immune Checkpoint Blockade into Chimeric Antigen Receptor T Cells (CAR-Ts: Combination or Built-In CAR-T

Directory of Open Access Journals (Sweden)

Dok Hyun Yoon

2018-01-01

Full Text Available Chimeric antigen receptor (CAR T cell therapy represents the first U.S. Food and Drug Administration approved gene therapy and these engineered cells function with unprecedented efficacy in the treatment of refractory CD19 positive hematologic malignancies. CAR translation to solid tumors is also being actively investigated; however, efficacy to date has been variable due to tumor-evolved mechanisms that inhibit local immune cell activity. To bolster the potency of CAR-T cells, modulation of the immunosuppressive tumor microenvironment with immune-checkpoint blockade is a promising strategy. The impact of this approach on hematological malignancies is in its infancy, and in this review we discuss CAR-T cells and their synergy with immune-checkpoint blockade.

The effect of opioid receptor blockade on the neural processing of thermal stimuli.

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Eszter D Schoell

Full Text Available 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.

Repeated Blockade of NMDA Receptors during Adolescence Impairs Reversal Learning and Disrupts GABAergic Interneurons in Rat Medial Prefrontal Cortex

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Jitao eLi

2016-03-01

Full Text Available Adolescence is of particular significance to schizophrenia, since psychosis onset typically occurs in this critical period. Based on the N-methyl-D-aspartate (NMDA receptor hypofunction hypothesis of schizophrenia, in this study, we investigated whether and how repeated NMDA receptor blockade during adolescence would affect GABAergic interneurons in rat medial prefrontal cortex (mPFC and mPFC-mediated cognitive functions. Specifically, adolescent rats were subjected to intraperitoneal administration of MK-801 (0.1, 0.2, 0.4 mg/kg, a non-competitive NMDA receptor antagonist, for 14 days and then tested for reference memory and reversal learning in the water maze. The density of parvabumin (PV-, calbindin (CB- and calretinin (CR-positive neurons in mPFC were analyzed at either 24 hours or 7 days after drug cessation. We found that MK-801 treatment delayed reversal learning in the water maze without affecting initial acquisition. Strikingly, MK-801 treatment also significantly reduced the density of PV+ and CB+ neurons, and this effect persisted for 7 days after drug cessation at the dose of 0.2 mg/kg. We further demonstrated that the reduction in PV+ and CB+ neuron densities was ascribed to a downregulation of the expression levels of PV and CB, but not to neuronal death. These results parallel the behavioral and neuropathological changes of schizophrenia and provide evidence that adolescent NMDA receptors antagonism offers a useful tool for unraveling the etiology of the disease.

Renin-angiotensin system blockade therapy after transcatheter aortic valve implantation.

Science.gov (United States)

Ochiai, Tomoki; Saito, Shigeru; Yamanaka, Futoshi; Shishido, Koki; Tanaka, Yutaka; Yamabe, Tsuyoshi; Shirai, Shinichi; Tada, Norio; Araki, Motoharu; Naganuma, Toru; Watanabe, Yusuke; Yamamoto, Masanori; Hayashida, Kentaro

2018-04-01

The persistence of left ventricular (LV) hypertrophy is associated with poor clinical outcomes after transcatheter aortic valve implantation (TAVI) for aortic stenosis. However, the optimal medical therapy after TAVI remains unknown. We investigated the effect of renin-angiotensin system (RAS) blockade therapy on LV hypertrophy and mortality in patients undergoing TAVI. Between October 2013 and April 2016, 1215 patients undergoing TAVI were prospectively enrolled in the Optimized CathEter vAlvular iNtervention (OCEAN)-TAVI registry. This cohort was stratified according to the postoperative usage of RAS blockade therapy with angiotensin-converting enzyme (ACE) inhibitors or angiotensin-receptor blockers (ARBs). Patients with at least two prescriptions dispensed 180 days apart after TAVI and at least a 6-month follow-up constituted the RAS blockade group (n=371), while those not prescribed any ACE inhibitors or ARBs after TAVI were included in the no RAS blockade group (n=189). At 6 months postoperatively, the RAS blockade group had significantly greater LV mass index regression than the no RAS blockade group (-9±24% vs -2±25%, p=0.024). Kaplan-Meier analysis revealed a significantly lower cumulative 2-year mortality in the RAS blockade than that in the no RAS blockade group (7.5% vs 12.5%; log-rank test, p=0.031). After adjusting for confounding factors, RAS blockade therapy was associated with significantly lower all-cause mortality (HR, 0.45; 95% CI 0.22 to 0.91; p=0.025). Postoperative RAS blockade therapy is associated with greater LV mass index regression and reduced all-cause mortality. These data need to be confirmed by a prospective randomised controlled outcome trial. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Bradykinin receptor blockade restores the baroreflex control of renal sympathetic nerve activity in cisplatin-induced renal failure rats.

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Abdulla, M H; Duff, M; Swanton, H; Johns, E J

2016-11-01

This study investigated the effect of renal bradykinin B1 and B2 receptor blockade on the high- and low-pressure baroreceptor reflex regulation of renal sympathetic nerve activity (RSNA) in rats with cisplatin-induced renal failure. Cisplatin (5 mg/kg) or saline was given intraperitoneally 4 days prior to study. Following chloralose/urethane anaesthesia, rats were prepared for measurement of mean arterial pressure (MAP), heart rate and RSNA and received intrarenal infusions of either Lys-[des-Arg 9 , Leu 8 ]-bradykinin (LBK), a bradykinin B1 receptor blocker, or bradyzide (BZ), a bradykinin B2 receptor blocker. RSNA baroreflex gain curves and renal sympatho-inhibitory responses to volume expansion (VE) were obtained. In the control and renal failure groups, basal MAP (89 ± 3 vs. 80 ± 8 mmHg) and RSNA (2.0 ± 0.3 vs. 1.7 ± 0.6 μV.s) were similar but HR was lower in the latter group (331 ± 8 vs. 396 ± 9 beats/min). The baroreflex gain for RSNA in the renal failure rats was 39% (P renal failure rats. Intrarenal LBK infusion in the renal failure rats normalized the VE induced renal sympatho-inhibition whereas BZ only partially restored the response. These findings suggest that pro-inflammatory bradykinin acting at different receptors within the kidney generates afferent neural signals which impact differentially within the central nervous system on high- and low-pressure regulation of RSNA. © 2016 Scandinavian Physiological Society. Published by John Wiley & Sons Ltd.

Blockade of NMDA receptors blocks the acquisition of cocaine conditioned approach in rats.

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Galaj, Ewa; Seepersad, Neal; Dakmak, Zena; Ranaldi, Robert

2018-01-05

Conditioned stimuli (CSs) exert motivational effects on both adaptive and pathological reward-related behaviors, including drug taking and seeking. We developed a paradigm that allows us to investigate the neuropharmacology by which previously neutral stimuli acquire the capacity to function as CSs and elicit (intravenous) cocaine conditioned approach and used this paradigm to test the role of NMDA receptor stimulation in the acquisition of cocaine conditioned approach. Rats were injected systemically with the NMDA receptor antagonist, MK-801, before the start of 4 consecutive conditioning sessions, each of which consisted of 20 randomly presented light/tone (CS) presentations paired with cocaine infusion contingent upon nose pokes. Rats later were subjected to a CS-only test. To test the role of NMDA receptor stimulation in the already established conditioned approach, rats were injected with MK-801 prior to the CS-only test that occurred after 18 CS-cocaine conditioning sessions. Blockade of NMDA receptors significantly impaired the acquisition of cocaine-conditioned approach as indicated by the emission of significantly fewer nose pokes and significantly longer latencies to nose poke during CS presentations. When MK-801 treatment was applied after the acquisition of conditioned approach responding it had no effect on these measures. These results suggest that NMDA receptor stimulation plays an important role in the acquisition of reward-related conditioned responses driven by intravenous cocaine-associated CSs. Copyright © 2017 Elsevier B.V. All rights reserved.

Polymorphisms in the endocannabinoid receptor 1 in relation to fat mass distribution

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Frost, M; Nielsen, T L; Wraae, K

2010-01-01

Both animal and human studies have associated the endocannabinoid system with obesity and markers of metabolic dysfunction. Blockade of the cannabinoid receptor 1 (CB1) caused weight loss and reduction in waist size in both obese and type II diabetics. Recent studies on common variants of the CB1...... receptor gene (CNR1) and the link to obesity have been conflicting. The aim of the present study was to evaluate whether selected common variants of the CNR1 are associated with measures of obesity and fat distribution....

Role of endocannabinoids and cannabinoid-1 receptors in cerebrocortical blood flow regulation.

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András Iring

Full Text Available Endocannabinoids are among the most intensively studied lipid mediators of cardiovascular functions. In the present study the effects of decreased and increased activity of the endocannabinoid system (achieved by cannabinoid-1 (CB1 receptor blockade and inhibition of cannabinoid reuptake, respectively on the systemic and cerebral circulation were analyzed under steady-state physiological conditions and during hypoxia and hypercapnia (H/H.In anesthetized spontaneously ventilating rats the CB1-receptor antagonist/inverse agonist AM-251 (10 mg/kg, i.v. failed to influence blood pressure (BP, cerebrocortical blood flow (CoBF, measured by laser-Doppler flowmetry or arterial blood gas levels. In contrast, the putative cannabinoid reuptake inhibitor AM-404 (10 mg/kg, i.v. induced triphasic responses, some of which could be blocked by AM-251. Hypertension during phase I was resistant to AM-251, whereas the concomitant CoBF-increase was attenuated. In contrast, hypotension during phase III was sensitive to AM-251, whereas the concomitant CoBF-decrease was not. Therefore, CoBF autoregulation appeared to shift towards higher BP levels after CB1-blockade. During phase II H/H developed due to respiratory depression, which could be inhibited by AM-251. Interestingly, however, the concomitant rise in CoBF remained unchanged after AM-251, indicating that CB1-blockade potentially enhanced the reactivity of the CoBF to H/H. In accordance with this hypothesis, AM-251 induced a significant enhancement of the CoBF responses during controlled stepwise H/H.Under resting physiological conditions CB1-receptor mediated mechanisms appear to have limited influence on systemic or cerebral circulation. Enhancement of endocannabinoid levels, however, induces transient CB1-independent hypertension and sustained CB1-mediated hypotension. Furthermore, enhanced endocannabinoid activity results in respiratory depression in a CB1-dependent manner. Finally, our data indicate for the

No effect of angiotensin II AT(2)-receptor antagonist PD 123319 on cerebral blood flow autoregulation

DEFF Research Database (Denmark)

Estrup, T M; Paulson, O B; Strandgaard, S

2001-01-01

Blockade of the renin-angiotensin system with angiotensin-converting enzyme inhibitors (ACE-I) or angiotensin AT1-receptor antagonists shift the limits of autoregulation of cerebral blood flow (CBF) towards lower blood pressure (BP). The role of AT2-receptors in the regulation of the cerebral...... group. CBF was measured by the intracarotid 133xenon injection method and BP was raised by noradrenaline infusion and lowered by controlled haemorrhage in separate groups of rats. The limits of autoregulation were determined by computed least-sum-of-squares analysis. PD 123319 did not influence baseline...

Impact of endothelin blockade on acute exercise-induced changes in blood flow and endothelial function in type 2 diabetes mellitus.

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Schreuder, Tim H A; van Lotringen, Jaap H; Hopman, Maria T E; Thijssen, Dick H J

2014-09-01

Positive vascular effects of exercise training are mediated by acute increases in blood flow. Type 2 diabetes patients show attenuated exercise-induced increases in blood flow, possibly mediated by the endothelin pathway, preventing an optimal stimulus for vascular adaptation. We examined the impact of endothelin receptor blockade (bosentan) on exercise-induced blood flow in the brachial artery and on pre- and postexercise endothelial function in type 2 diabetes patients (n = 9, 60 ± 7 years old) and control subjects (n = 10, 60 ± 5 years old). Subjects reported twice to the laboratory to perform hand-grip exercise in the presence of endothelin receptor blockade or placebo. We examined brachial artery endothelial function (via flow-mediated dilatation) before and after exercise, as well as blood flow during exercise. Endothelin receptor blockade resulted in a larger increase in blood flow during exercise in type 2 diabetes patients (P = 0.046), but not in control subjects (P = 0.309). Exercise increased shear rate across the exercise protocol, unaffected by endothelin receptor blockade. Exercise did not alter brachial artery diameter in either group, but endothelin receptor blockade resulted in a larger brachial artery diameter in type 2 diabetes patients (P = 0.033). Exercise significantly increased brachial artery flow-mediated dilatation in both groups, unaffected by endothelin receptor blockade. Endothelin receptor blockade increased exercise-induced brachial artery blood flow in type 2 diabetes patients, but not in control subjects. Despite this effect of endothelin receptor blockade on blood flow, we found no impact on baseline or post-exercise endothelial function in type 2 diabetes patients or control subjects, possibly related to normalization of the shear stimulus during exercise. The successful increase in blood flow during exercise in type 2 diabetes patients through endothelin receptor blockade may have beneficial effects in

Rapid synthesis of acetylcholine receptors at neuromuscular junctions.

Science.gov (United States)

Ramsay, D A; Drachman, D B; Pestronk, A

1988-10-11

The rate of acetylcholine receptor (AChR) degradation in mature, innervated mammalian neuromuscular junctions has recently been shown to be biphasic; up to 20% are rapidly turned over (RTOs; half life less than 1 day) whereas the remainder are lost more slowly ('stable' AChRs; half life 10-12 days). In order to maintain normal junctional receptor density, synthesis and insertion of AChRs should presumably be sufficiently rapid to replace both the RTOs and the stable receptors. We have tested this prediction by blocking pre-existing AChRs in the mouse sternomastoid muscle with alpha-bungarotoxin (alpha-BuTx), and monitoring the subsequent appearance of 'new' junctional AChRs at intervals of 3 h to 20 days by labeling them with 125I-alpha-BuTx. The results show that new receptors were initially inserted rapidly (16% at 24 h and 28% at 48 h). The rate of increase of 'new' 125I-alpha-BuTx binding sites gradually slowed down during the remainder of the time period studied. Control observations excluded possible artifacts of the experimental procedure including incomplete blockade of AChRs, dissociation of toxin-receptor complexes, or experimentally induced alteration of receptor synthesis. The present demonstration of rapid synthesis and incorporation of AChRs at innervated neuromuscular junctions provides support for the concept of a subpopulation of rapidly turned over AChRs. The RTOs may serve as precursors for the larger population of stable receptors and have an important role in the metabolism of the neuromuscular synapse.

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

Directory of Open Access Journals (Sweden)

Stefanie Krajewski

Full Text Available 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(2Y(12 and P(2Y(1 blockade and PI3K p110β inhibition on platelets and granulocytes during hypothermic ECC. Human blood was treated with the P(2Y(12 antagonist 2-MeSAMP, the P(2Y(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(2Y 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(2Y and PI3K blockade or a combination thereof inhibited P-selectin expression on platelets and platelet-derived microparticles during hypothermic ECC (p<0.05. P(2Y 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(2Y and PI3K blockade (p<0.05. Combined blockade of P

Systemic modulation of serotonergic synapses via reuptake blockade or 5HT1A receptor antagonism does not alter perithreshold taste sensitivity in rats.

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Mathes, Clare M; Spector, Alan C

2014-09-01

Systemic blockade of serotonin (5HT) reuptake with paroxetine has been shown to increase sensitivity to sucrose and quinine in humans. Here, using a 2-response operant taste detection task, we measured the effect of paroxetine and the 5HT1A receptor antagonist WAY100635 on the ability of rats to discriminate sucrose, NaCl, and citric acid from water. After establishing individual psychometric functions, 5 concentrations of each taste stimulus were chosen to represent the dynamic portion of the concentration-response curve, and the performance of the rats to these stimuli was assessed after vehicle, paroxetine (7mg/kg intraperitoneally), and WAY100635 (0.3mg/kg subcutaneously; 1mg/kg intravenously) administration. Although, at times, overall performance across concentrations dropped, at most, 5% from vehicle to drug conditions, no differences relative to vehicle were seen on the parameters of the psychometric function (asymptote, slope, or EC50) after drug administration. In contrast to findings in humans, our results suggest that modulation of 5HT activity has little impact on sucrose detectability at perithreshold concentrations in rats, at least at the doses used in this task. In the rat model, the purported paracrine/neurocrine action of serotonin in the taste bud may work in a manner that does not impact overt taste detection behavior. © The Author 2014. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

β-Nicotinamide adenine dinucleotide acts at prejunctional adenosine A1 receptors to suppress inhibitory musculomotor neurotransmission in guinea pig colon and human jejunum

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Wang, Guo-Du; Wang, Xi-Yu; Liu, Sumei; Xia, Yun; Zou, Fei; Qu, Meihua; Needleman, Bradley J.; Mikami, Dean J.

2015-01-01

Intracellular microelectrodes were used to record neurogenic inhibitory junction potentials in the intestinal circular muscle coat. Electrical field stimulation was used to stimulate intramural neurons and evoke contraction of the smooth musculature. Exposure to β-nicotinamide adenine dinucleotide (β-NAD) did not alter smooth muscle membrane potential in guinea pig colon or human jejunum. ATP, ADP, β-NAD, and adenosine, as well as the purinergic P2Y1 receptor antagonists MRS 2179 and MRS 2500 and the adenosine A1 receptor agonist 2-chloro-N6-cyclopentyladenosine, each suppressed inhibitory junction potentials in guinea pig and human preparations. β-NAD suppressed contractile force of twitch-like contractions evoked by electrical field stimulation in guinea pig and human preparations. P2Y1 receptor antagonists did not reverse this action. Stimulation of adenosine A1 receptors with 2-chloro-N6-cyclopentyladenosine suppressed the force of twitch contractions evoked by electrical field stimulation in like manner to the action of β-NAD. Blockade of adenosine A1 receptors with 8-cyclopentyl-1,3-dipropylxanthine suppressed the inhibitory action of β-NAD on the force of electrically evoked contractions. The results do not support an inhibitory neurotransmitter role for β-NAD at intestinal neuromuscular junctions. The data suggest that β-NAD is a ligand for the adenosine A1 receptor subtype expressed by neurons in the enteric nervous system. The influence of β-NAD on intestinal motility emerges from adenosine A1 receptor-mediated suppression of neurotransmitter release at inhibitory neuromuscular junctions. PMID:25813057

Inverse agonism at the P2Y12 receptor and ENT1 transporter blockade contribute to platelet inhibition by ticagrelor.

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Aungraheeta, Riyaad; Conibear, Alexandra; Butler, Mark; Kelly, Eamonn; Nylander, Sven; Mumford, Andrew; Mundell, Stuart J

2016-12-08

Ticagrelor is a potent antagonist of the P2Y 12 receptor (P2Y 12 R) and consequently an inhibitor of platelet activity effective in the treatment of atherothrombosis. Here, we sought to further characterize its molecular mechanism of action. Initial studies showed that ticagrelor promoted a greater inhibition of adenosine 5'-diphosphate (ADP)-induced Ca 2+ release in washed platelets vs other P2Y 12 R antagonists. This additional effect of ticagrelor beyond P2Y 12 R antagonism was in part as a consequence of ticagrelor inhibiting the equilibrative nucleoside transporter 1 (ENT1) on platelets, leading to accumulation of extracellular adenosine and activation of G s -coupled adenosine A 2A receptors. This contributed to an increase in basal cyclic adenosine monophosphate (cAMP) and vasodilator-stimulated phosphoprotein phosphorylation (VASP-P). In addition, ticagrelor increased platelet cAMP and VASP-P in the absence of ADP in an adenosine receptor-independent manner. We hypothesized that this increase originated from a direct effect on basal agonist-independent P2Y 12 R signaling, and this was validated in 1321N1 cells stably transfected with human P2Y 12 R. In these cells, ticagrelor blocked the constitutive agonist-independent activity of the P2Y 12 R, limiting basal G i -coupled signaling and thereby increasing cAMP levels. These data suggest that ticagrelor has the pharmacological profile of an inverse agonist. Based on our results showing insurmountable inhibition of ADP-induced Ca 2+ release and forskolin-induced cAMP, the mode of antagonism of ticagrelor also appears noncompetitive, at least functionally. In summary, our studies describe 2 novel modes of action of ticagrelor, inhibition of platelet ENT1 and inverse agonism at the P2Y 12 R that contribute to its effective inhibition of platelet activation. © 2016 by The American Society of Hematology.

CB1 receptor antagonism increases hippocampal acetylcholine release: site and mechanism of action.

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Degroot, Aldemar; Köfalvi, Attila; Wade, Mark R; Davis, Richard J; Rodrigues, Ricardo J; Rebola, Nelson; Cunha, Rodrigo A; Nomikos, George G

2006-10-01

Evidence indicates that blockade of cannabinoid receptors increases acetylcholine (ACh) release in brain cortical regions. Although it is assumed that this type of effect is mediated through CB1 receptor (CB1R) antagonism, several in vitro functional studies recently have suggested non-CB1R involvement. In addition, neither the precise neuroanatomical site nor the exact mechanisms underlying this effect are known. We thoroughly examined these issues using a combination of systemic and local administration of CB1R antagonists, different methods of in vivo microdialysis, CB1R knockout (KO) mice, tissue measurements of ACh, and immunochemistry. First, we showed that systemic injections of the CB1R antagonists N-(piperidin-1-yl)-5-(4-chlorophenyl)-1-(2,4-dichlorophenyl)-4-methyl-1H-pyrazole-3-carboximide hydrochloride (SR-141716A) and N-(piperidin-1-yl)-5-(4-iodophenyl)-1-(2, 4-dichlorophenyl)-4-methyl-1H-pyrazole-3-carboxamide (AM251) dose-dependently increased hippocampal ACh efflux. Likewise, local hippocampal, but not septal, infusions of SR141716A or AM251 increased hippocampal ACh release. It is noteworthy that the stimulatory effects of systemically administered CB1R antagonists on hippocampal ACh release were completely abolished in CB1R KO mice. CB1R KO mice had similar basal but higher stress-enhanced hippocampal ACh levels compared with wild-type controls. It is interesting that dopamine D1 receptor antagonism counteracted the stimulatory effect of CB1R blockade on hippocampal ACh levels. Finally, immunohistochemical methods revealed that a high proportion of CB1R-positive nerve terminals were found in hippocampus and confirmed the colocalization of CB1 receptors with cholinergic and dopaminergic nerve terminals. In conclusion, hippocampal ACh release may specifically be controlled through CB1Rs located on both cholinergic and dopaminergic neuronal projections, and CB1R antagonism increases hippocampal ACh release, probably through both a direct

Cerebral A1 adenosine receptors (A1AR) in liver cirrhosis

International Nuclear Information System (INIS)

Boy, Christian; Meyer, Philipp T.; Kircheis, Gerald; Haussinger, Dieter; Holschbach, Marcus H.; Coenen, Heinz H.; Herzog, Hans; Elmenhorst, David; Kaiser, Hans J.; Zilles, Karl; Bauer, Andreas

2008-01-01

The cerebral mechanisms underlying hepatic encephalopathy (HE) are poorly understood. Adenosine, a neuromodulator that pre- and postsynaptically modulates neuronal excitability and release of classical neurotransmitters via A 1 adenosine receptors (A 1 AR), is likely to be involved. The present study investigates changes of cerebral A 1 AR binding in cirrhotic patients by means of positron emission tomography (PET) and [ 18 F]CPFPX, a novel selective A 1 AR antagonist. PET was performed in cirrhotic patients (n = 10) and healthy volunteers (n = 10). Quantification of in vivo receptor density was done by Logan's non-invasive graphical analysis (pons as reference region). The outcome parameter was the apparent binding potential (aBP, proportional to B max /K D ). Cortical and subcortical regions showed lower A 1 AR binding in cirrhotic patients than in controls. The aBP changes reached statistical significance vs healthy controls (p 1 AR binding may further aggravate neurotransmitter imbalance at the synaptic cleft in cirrhosis and hepatic encephalopathy. Different pathomechanisms may account for these alterations including decrease of A 1 AR density or affinity, as well as blockade of the A 1 AR by endogenous adenosine or exogenous xanthines. (orig.)

Dual hypocretin receptor antagonism is more effective for sleep promotion than antagonism of either receptor alone.

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Stephen R Morairty

Full Text Available The hypocretin (orexin system is involved in sleep/wake regulation, and antagonists of both hypocretin receptor type 1 (HCRTR1 and/or HCRTR2 are considered to be potential hypnotic medications. It is currently unclear whether blockade of either or both receptors is more effective for promoting sleep with minimal side effects. Accordingly, we compared the properties of selective HCRTR1 (SB-408124 and SB-334867 and HCRTR2 (EMPA antagonists with that of the dual HCRTR1/R2 antagonist almorexant in the rat. All 4 antagonists bound to their respective receptors with high affinity and selectivity in vitro. Since in vivo pharmacokinetic experiments revealed poor brain penetration for SB-408124, SB-334867 was selected for subsequent in vivo studies. When injected in the mid-active phase, SB-334867 produced small increases in rapid-eye-movement (REM and non-REM (NR sleep. EMPA produced a significant increase in NR only at the highest dose studied. In contrast, almorexant decreased NR latency and increased both NR and REM proportionally throughout the subsequent 6 h without rebound wakefulness. The increased NR was due to a greater number of NR bouts; NR bout duration was unchanged. At the highest dose tested (100 mg/kg, almorexant fragmented sleep architecture by increasing the number of waking and REM bouts. No evidence of cataplexy was observed. HCRTR1 occupancy by almorexant declined 4-6 h post-administration while HCRTR2 occupancy was still elevated after 12 h, revealing a complex relationship between occupancy of HCRT receptors and sleep promotion. We conclude that dual HCRTR1/R2 blockade is more effective in promoting sleep than blockade of either HCRTR alone. In contrast to GABA receptor agonists which induce sleep by generalized inhibition, HCRTR antagonists seem to facilitate sleep by reducing waking "drive".

The non-biphenyl-tetrazole angiotensin AT1 receptor antagonist eprosartan is a unique and robust inverse agonist of the active state of the AT1 receptor.

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Takezako, Takanobu; Unal, Hamiyet; Karnik, Sadashiva S; Node, Koichi

2018-03-23

Conditions such as hypertension and renal allograft rejection are accompanied by chronic, agonist-independent, signalling by angiotensin II AT 1 receptors. The current treatment paradigm for these diseases entails the preferred use of inverse agonist AT 1 receptor blockers (ARBs). However, variability in the inverse agonist activities of common biphenyl-tetrazole ARBs for the active state of AT 1 receptors often leads to treatment failure. Therefore, characterization of robust inverse agonist ARBs for the active state of AT 1 receptors is necessary. To identify the robust inverse agonist for active state of AT 1 receptors and its molecular mechanism, we performed site-directed mutagenesis, competition binding assay, inositol phosphate production assay and molecular modelling for both ground-state wild-type AT 1 receptors and active-state N111G mutant AT 1 receptors. Although candesartan and telmisartan exhibited weaker inverse agonist activity for N111G- compared with WT-AT 1 receptors, only eprosartan exhibited robust inverse agonist activity for both N111G- and WT- AT 1 receptors. Specific ligand-receptor contacts for candesartan and telmisartan are altered in the active-state N111G- AT 1 receptors compared with the ground-state WT-AT 1 receptors, suggesting an explanation of their attenuated inverse agonist activity for the active state of AT 1 receptors. In contrast, interactions between eprosartan and N111G-AT 1 receptors were not significantly altered, and the inverse agonist activity of eprosartan was robust. Eprosartan may be a better therapeutic option than other ARBs. Comparative studies investigating eprosartan and other ARBs for the treatment of diseases caused by chronic, agonist-independent, AT 1 receptor activation are warranted. © 2018 The British Pharmacological Society.

Differential effects of m1 and m2 receptor antagonists in perirhinal cortex on visual recognition memory in monkeys.

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Wu, Wei; Saunders, Richard C; Mishkin, Mortimer; Turchi, Janita

2012-07-01

Microinfusions of the nonselective muscarinic antagonist scopolamine into perirhinal cortex impairs performance on visual recognition tasks, indicating that muscarinic receptors in this region play a pivotal role in recognition memory. To assess the mnemonic effects of selective blockade in perirhinal cortex of muscarinic receptor subtypes, we locally infused either the m1-selective antagonist pirenzepine or the m2-selective antagonist methoctramine in animals performing one-trial visual recognition, and compared these scores with those following infusions of equivalent volumes of saline. Compared to these control infusions, injections of pirenzepine, but not of methoctramine, significantly impaired recognition accuracy. Further, similar doses of scopolamine and pirenzepine yielded similar deficits, suggesting that the deficits obtained earlier with scopolamine were due mainly, if not exclusively, to blockade of m1 receptors. The present findings indicate that m1 and m2 receptors have functionally dissociable roles, and that the formation of new visual memories is critically dependent on the cholinergic activation of m1 receptors located on perirhinal cells. Published by Elsevier Inc.

Effect of adenosine1-receptor blockade on renin release from rabbit isolated perfused juxtaglomerular apparatus

DEFF Research Database (Denmark)

Weihprecht, H; Lorenz, J N; Schnermann, J

1990-01-01

Adenosine has been proposed to act within the juxtaglomerular apparatus (JGA) as a mediator of the inhibition of renin secretion produced by a high NaCl concentration at the macula densa. To test this hypothesis, we studied the effects of the adenosine1 (A1)-receptor blocker 8-cyclopentyl-1......,3-dipropylxanthine (CPX) on renin release from single isolated rabbit JGAs with macula densa perfused. The A1-receptor agonist, N6-cyclohexyladenosine (CHA), applied in the bathing solution at 10(-7) M, was found to inhibit renin secretion, an effect that was completely blocked by adding CPX (10(-5) M) to the bath....... Applied to the lumen, 10(-5) M CPX produced a modest stimulation of renin secretion rates suppressed by a high NaCl concentration at the macula densa (P less than 0.05). The effect of changing luminal NaCl concentration on renin secretion rate was examined in the presence of CPX (10(-7) and 10(-5) M...

Astrocyte reactivity to unconjugated bilirubin requires TNF-α and IL-1β receptor signaling pathways.

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Fernandes, Adelaide; Barateiro, Andreia; Falcão, Ana Sofia; Silva, Sandra Leit-Ao; Vaz, Ana Rita; Brito, Maria Alexandra; Silva, Rui Fernando Marques; Brites, Dora

2011-01-01

Jaundice and sepsis are common neonatal conditions that can lead to neurodevelopment sequelae, namely if present at the same time. We have reported that tumor necrosis factor (TNF)-α and interleukin (IL)-1β are produced by cultured neurons and mainly by glial cells exposed to unconjugated bilirubin (UCB). The effects of these cytokines are mediated by cell surface receptors through a nuclear factor (NF)-κB-dependent pathway that we have showed to be activated by UCB. The present study was designed to evaluate the role of TNF-α and IL-1β signaling on astrocyte reactivity to UCB in rat cortical astrocytes. Exposure of astrocytes to UCB increased the expression of both TNF-α receptor (TNFR)1 and IL-1β receptor (IL-1R)1, but not TNFR2, as well as their activation, observed by augmented binding of receptors' molecular adaptors, TRAF2 and TRAF6, respectively. Silencing of TNFR1, using siRNA technology, or blockade of IL-1β cascade, using its endogenous antagonist, IL-1 receptor antagonist (IL-1ra), prevented UCB-induced cytokine release and NF-κB activation. Interestingly, lack of TNF-α signal transduction reduced UCB-induced cell death for short periods of incubation, although an increase was observed after extended exposure; in contrast, inhibition of IL-1β cascade produced a sustained blockade of astrocyte injury by UCB. Together, our data show that inflammatory pathways are activated during in vitro exposure of rat cortical astrocytes to UCB and that this activation is prolonged in time. This supports the concept that inflammatory pathways play a role in brain damage by UCB, and that they may represent important pharmacological targets. Copyright © 2010 Wiley-Liss, Inc.

Sigma-1 receptor and inflammatory pain.

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Gris, Georgia; Cobos, Enrique José; Zamanillo, Daniel; Portillo-Salido, Enrique

2015-06-01

The sigma-1 receptor (Sig-1R) is a unique ligand-regulated molecular chaperone that interacts with several protein targets such as G protein-coupled receptors and ion channels to modulate their activity. Sig-1R is located in areas of the central and peripheral nervous system that are key to pain control. Previous preclinical studies have suggested a potential therapeutic use of Sig-1R antagonists for the management of neuropathic pain. Recent studies using pharmacological and genetic tools have explored the role of Sig-1R in inflammatory pain conditions. Mice lacking the Sig-1R have shown different patterns of phenotypic responses to inflammatory injury. Systemic or peripheral administration of several Sig-1R antagonists, including the selective Sig-1R antagonist S1RA, inhibited both mechanical and thermal hypersensitivity in several preclinical models of inflammatory pain. These recent studies are summarized in the present commentary. Central and peripheral pharmacological blockade of Sig-1R could be an effective option to treat inflammatory pain.

Reversal of propranolol blockade of adrenergic receptors and related toxicity with drugs that increase cyclic AMP.

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Whitehurst, V E; Vick, J A; Alleva, F R; Zhang, J; Joseph, X; Balazs, T

1999-09-01

An overdose of propranolol, a widely used nonselective beta-adrenergic receptor blocking agent, can result in hypotension and bradycardia leading to irreversible shock and death. In addition, the blockade of adrenergic receptors can lead to alterations in neurotransmitter receptors resulting in the interruption of the activity of other second messengers and the ultimate cellular responses. In the present experiment, three agents, aminophylline, amrinone, and forskolin were tested in an attempt to reverse the potential lethal effects of a propranolol overdose in dogs. Twenty-two anesthetized beagle dogs were given a 10-min infusion of propranolol at a dose of 1 mg/kg/min. Six of the dogs, treated only with intravenous saline, served as controls. Within 15-30 min all six control dogs exhibited profound hypotension and severe bradycardia that led to cardiogenic shock and death. Seven dogs were treated with intravenous aminophylline 20 mg/kg 5 min after the end of the propranolol infusion. Within 10-15 min heart rate and systemic arterial blood pressure returned to near control levels, and all seven dogs survived. Intravenous amrinone (2-3 mg/kg) given to five dogs, and forskolin (1-2 mg/kg) given to four dogs, also increased heart rate and systemic arterial blood pressure but the recovery of these parameters was appreciably slower than that seen with aminophylline. All of these animals also survived with no apparent adverse effects. Histopathologic evaluation of the hearts of the dogs treated with aminophylline showed less damage (vacuolization, inflammation, hemorrhage) than the hearts from animals given propranolol alone. Results of this study showed that these three drugs, all of which increase cyclic AMP, are capable of reversing the otherwise lethal effects of a propranolol overdose in dogs.

Embryonic GABA(B receptor blockade alters cell migration, adult hypothalamic structure, and anxiety- and depression-like behaviors sex specifically in mice.

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Matthew S Stratton

Full Text Available 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.

Hydronephrosis alters cardiac ACE2 and Mas receptor expression in mice.

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Zhang, Yanling; Ma, Lulu; Wu, Junyan; Chen, Tingting

2015-06-01

Hydronephrosis is characterized by substantial loss of tubules and affects renin secretion in the kidney. However, whether alterations of angiotensin-converting enzyme (ACE), ACE2 and Mas receptor in the heart are observed in hydronephrosis is unknown. Thus, we assessed these components in hydronephrotic mice treated with AT1 receptor blockade and ACE inhibitor. Hydronephrosis was induced by left ureteral ligation in Balb/C mice except sham-operated animals. The levels of cardiac ACE, ACE2 and Mas receptor were measured after treatment of losartan or enalapril. Hydronephrosis led to an increase of ACE level and a decrease of ACE2 and Mas receptor in the heart. Losartan decreased cardiac ACE level, but ACE2 and Mas receptor levels significantly increased in hydronephrotic mice (p Hydronephrosis increased cardiac ACE and suppressed ACE2 and Mas receptor levels. AT1 blockade caused sustained activation of cardiac ACE2 and Mas receptor, but ACE inhibitor had the limitation of such activation of Mas receptor in hydronephrotic animals. © The Author(s) 2015.

Temporal responses of cutaneous blood flow and plasma catecholamine concentrations to histamine H1- or H2-receptor stimulation in man

DEFF Research Database (Denmark)

Knigge, U; Alsbjørn, B; Thuesen, B

1988-01-01

continuously with a laser Doppler flowmeter, and noradrenaline and adrenaline concentrations were determined in blood samples drawn every 15 min. The infusion of histamine caused an immediate and sustained vasodilatation. The Concomitant infusion of mepyramine prevented the immediate vasodilatation, but had...... noradrenaline, while the increase during concomitant H1-receptor blockade was delayed but achieved the level observed during the histamine infusion. The response to histamine during H2-receptor blockade was small and transient. The rise in plasma adrenaline was not significant. These findings suggest...

α2-adrenergic blockade mimics the enhancing effect of chronic stress on breast cancer progression

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Lamkin, Donald M.; Sung, Ha Yeon; Yang, Gyu Sik; David, John M.; Ma, Jeffrey C.Y.; Cole, Steve W.; Sloan, Erica K.

2014-01-01

Experimental studies in preclinical mouse models of breast cancer have shown that chronic restraint stress can enhance disease progression by increasing catecholamine levels and subsequent signaling of β-adrenergic receptors. Catecholamines also signal α-adrenergic receptors, and greater α-adrenergic signaling has been shown to promote breast cancer in vitro and in vivo. However, antagonism of α-adrenergic receptors can result in elevated catecholamine levels, which may increase β-adrenergic signaling, because pre-synaptic α2-adrenergic receptors mediate an autoinhibition of sympathetic transmission. Given these findings, we examined the effect of α-adrenergic blockade on breast cancer progression under non-stress and stress conditions (chronic restraint) in an orthotopic mouse model with MDA-MB-231HM cells. Chronic restraint increased primary tumor growth and metastasis to distant tissues as expected, and non-selective α-adrenergic blockade by phentolamine significantly inhibited those effects. However, under non-stress conditions, phentolamine increased primary tumor size and distant metastasis. Sympatho-neural gene expression for catecholamine biosynthesis enzymes was elevated by phentolamine under non-stress conditions, and the non-selective β-blocker propranolol inhibited the effect of phentolamine on breast cancer progression. Selective α2-adrenergic blockade by efaroxan also increased primary tumor size and distant metastasis under non-stress conditions, but selective α1-adrenergic blockade by prazosin did not. These results are consistent with the hypothesis that α2-adrenergic signaling can act through an autoreceptor mechanism to inhibit sympathetic catecholamine release and, thus, modulate established effects of β-adrenergic signaling on tumor progression-relevant biology. PMID:25462899

Dissociation between cardiomyocyte function and remodeling with beta-adrenergic receptor blockade in isolated canine mitral regurgitation.

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Pat, Betty; Killingsworth, Cheryl; Denney, Thomas; Zheng, Junying; Powell, Pamela; Tillson, Michael; Dillon, A Ray; Dell'Italia, Louis J

2008-12-01

The low-pressure volume overload of isolated mitral regurgitation (MR) is associated with increased adrenergic drive, left ventricular (LV) dilatation, and loss of interstitial collagen. We tested the hypothesis that beta1-adrenergic receptor blockade (beta1-RB) would attenuate LV remodeling after 4 mo of MR in the dog. beta1-RB did not attenuate collagen loss or the increase in LV mass in MR dogs. Using MRI and three-dimensional (3-D) analysis, there was a 70% increase in the LV end-diastolic (LVED) volume-to-LV mass ratio, a 23% decrease in LVED midwall circumferential curvature, and a >50% increase in LVED 3-D radius/wall thickness in MR dogs that was not attenuated by beta1-RB. However, beta1-RB caused a significant increase in LVED length from the base to apex compared with untreated MR dogs. This was associated with an increase in isolated cardiomyocyte length (171+/-5 microm, P<0.05) compared with normal (156+/-3 microm) and MR (165+/-4 microm) dogs. Isolated cardiomyocyte fractional shortening was significantly depressed in MR dogs compared with normal dogs (3.73+/-0.31 vs. 5.02+/-0.26%, P<0.05) and normalized with beta1-RB (4.73+/-0.48%). In addition, stimulation with the beta-adrenergic receptor agonist isoproterenol (25 nM) increased cardiomyocyte fractional shortening by 215% (P<0.05) in beta1-RB dogs compared with normal (56%) and MR (50%) dogs. In summary, beta1-RB improved LV cardiomyocyte function and beta-adrenergic receptor responsiveness despite further cell elongation. The failure to attenuate LV remodeling associated with MR could be due to a failure to improve ultrastructural changes in extracellular matrix organization.

Histamine 1 Receptor Blockade Enhances Eosinophil-Mediated Clearance of Adult Filarial Worms.

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Ellen Mueller Fox

Full Text Available Filariae are tissue-invasive nematodes that cause diseases such as elephantiasis and river blindness. The goal of this study was to characterize the role of histamine during Litomosoides sigmodontis infection of BALB/c mice, a murine model of filariasis. Time course studies demonstrated that while expression of histidine decarboxylase mRNA increases throughout 12 weeks of infection, serum levels of histamine exhibit two peaks-one 30 minutes after primary infection and one 8 weeks later. Interestingly, mice treated with fexofenadine, a histamine receptor 1 inhibitor, demonstrated significantly reduced worm burden in infected mice compared to untreated infected controls. Although fexofenadine-treated mice had decreased antigen-specific IgE levels as well as lower splenocyte IL-5 and IFNγ production, they exhibited a greater than fourfold rise in eosinophil numbers at the tissue site where adult L. sigmodontis worms reside. Fexofenadine-mediated clearance of L. sigmodontis worms was dependent on host eosinophils, as fexofenadine did not decrease worm burdens in eosinophil-deficient dblGATA mice. These findings suggest that histamine release induced by tissue invasive helminths may aid parasite survival by diminishing eosinophilic responses. Further, these results raise the possibility that combining H1 receptor inhibitors with current anthelmintics may improve treatment efficacy for filariae and other tissue-invasive helminths.

Consequence of dopamine D2 receptor blockade on the hyperphagic effect induced by cannabinoid CB1 and CB2 receptors in layers.

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Khodadadi, M; Zendehdel, M; Baghbanzadeh, A; Babapour, V

2017-10-01

1. Endocannabinoids (ECBs) and their receptors play a regulatory function on several physiological processes such as feed-intake behaviour, mainly in the brain. This study was carried out in order to investigate the effects of the dopaminergic D1 and D2 receptors on CB1/CB2 ECB receptor-induced hyperphagia in 3-h feed-deprived neonatal layer chickens. 2. A total of 8 experiments were designed to explore the interplay of these two modulatory systems on feed intake in neonatal chickens. In Experiment 1, chickens were intracerebroventricular (ICV) injected with control solution, l-DOPA (levo-dihydroxyphenylalanine as precursor of dopamine; 125 nmol), 2-AG (2-arachidonoylglycerol as CB 1 receptor agonist; 2 µg) and co-administration of l-DOPA (125 nmol) plus 2-AG (2 µg). Experiments 2-4 were similar to Experiment 1 except birds were injected with either 6-OHDA (6-hydroxydopamine as dopamine synthesis inhibitor; 150 nmol), SCH23390 (D1 receptor antagonist; 5 nmol) and AMI-193 (D2 receptor antagonist; 5 nmol) instead of l-DOPA, respectively. Additionally, Experiments 5-8 followed the previous ones using the same dose of l-DOPA, 6-OHDA and dopamine antagonists except that birds were injected with CB65 (CB2 receptor agonist; 5 µg) instead of 2-AG. Coadministrations were at the same dose for each experiment. Cumulative feed intakes were measured until 120 min after each injection. 3. ICV administration of 6-OHDA and AMI-193 significantly attenuated 2-AG-induced hyperphagia. Interestingly, the hyperphagic effect of CB65 was significantly attenuated by administration of l-DOPA, whereas the administration of 6-OHDA and AMI-193 together amplified the hyperphagic effect of CB65. 4. It was concluded that cannabinoid-induced feeding behaviour is probably modulated by dopamine receptors in neonatal layer-type chickens. It seems that their interaction may be mediated by the D2-dopamine receptor.

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

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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

Dual Blockade of the Renin-angiotensin-aldosterone System in Type 2 Diabetic Kidney Disease

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Yan-Huan Feng

2016-01-01

Full Text Available Objective: To examine the efficacy and safety of dual blockade of the renin-angiotensin-aldosterone system (RAAS among patients with type 2 diabetic kidney disease. Data Sources: We searched the major literature repositories, including the Cochrane Central Register of Controlled Trials, MEDLINE and EMBASE, for randomized clinical trials published between January 1990 and October 2015 that compared the efficacy and safety of the use of dual blockade of the RAAS versus the use of monotherapy, without applying any language restrictions. Keywords for the searches included "diabetic nephropathy," "chronic kidney disease," "chronic renal insufficiency," "diabetes mellitus," "dual therapy," "combined therapy," "dual blockade," "renin-angiotensin system," "angiotensin-converting enzyme inhibitor," "angiotensin-receptor blocker," "aldosterone blockade," "selective aldosterone blockade," "renin inhibitor," "direct renin inhibitor," "mineralocorticoid receptor blocker," etc. Study Selection: The selected articles were carefully reviewed. We excluded randomized clinical trials in which the kidney damage of patients was related to diseases other than diabetes mellitus. Results: Combination treatment with an angiotensin-converting enzyme inhibitor supplemented by an angiotensin II receptor blocking agent is expected to provide a more complete blockade of the RAAS and a better control of hypertension. However, existing literature has presented mixed results, in particular, related to patient safety. In view of this, we conducted a comprehensive literature review in order to explain the rationale for dual blockade of the RAAS, and to discuss the pros and cons. Conclusions: Despite the negative results of some recent large-scale studies, it may be immature to declare that the dual blockade is a failure because of the complex nature of the RAAS surrounding its diversified functions and utility. Further trials are warranted to study the combination therapy as an

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

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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

Synergistic reversal of type 1 diabetes in NOD mice with anti-CD3 and interleukin-1 blockade

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Ablamunits, Vitaly; Henegariu, Octavian; Hansen, Jakob Bondo

2012-01-01

(ab')(2) fragments of anti-CD3 mAb with or without IL-1 receptor antagonist (IL-1RA), or anti-IL-1ß mAb. We studied the reversal of diabetes and effects of treatment on the immune system. Mice that received a combination of anti-CD3 mAb with IL-1RA showed a more rapid rate of remission of diabetes than......Inflammatory cytokines are involved in autoimmune diabetes: among the most prominent is interleukin (IL)-1ß. We postulated that blockade of IL-1ß would modulate the effects of anti-CD3 monoclonal antibody (mAb) in treating diabetes in NOD mice. To test this, we treated hyperglycemic NOD mice with F...... arginase expression in macrophages and dendritic cells, and had delayed adoptive transfer of diabetes. After 1 month, there were increased concentrations of IgG1 isotype antibodies and reduced intrapancreatic expression of IFN-¿, IL-6, and IL-17 despite normal splenocyte cytokine secretion. These studies...

Testosterone receptor blockade after trauma-hemorrhage improves cardiac and hepatic functions in males.

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Remmers, D E; Wang, P; Cioffi, W G; Bland, K I; Chaudry, I H

1997-12-01

Although studies have shown that testosterone receptor blockade with flutamide after hemorrhage restores the depressed immune function, it remains unknown whether administration of flutamide following trauma and hemorrhage and resuscitation has any salutary effects on the depressed cardiovascular and hepatocellular functions. To study this, male rats underwent a laparotomy (representing trauma) and were then bled and maintained at a mean arterial pressure (MAP) of 40 mmHg until the animals could not maintain this pressure. Ringer lactate was given to maintain a MAP of 40 mmHg until 40% of the maximal shed blood volume was returned in the form of Ringer lactate. The rats were then resuscitated with four times the shed blood volume in the form of Ringer lactate over 60 min. Flutamide (25 mg/kg) or an equal volume of the vehicle propanediol was injected subcutaneously 15 min before the end of resuscitation. Various in vivo heart performance parameters (e.g., maximal rate of the pressure increase or decrease), cardiac output, and hepatocellular function (i.e., the maximum velocity and the overall efficiency of indocyanine green clearance) were determined at 20 h after resuscitation. Additionally, hepatic microvascular blood flow (HMBF) was determined using a laser Doppler flowmeter. The results indicate that left ventricular performance, cardiac output, HMBF, and hepatocellular function decreased significantly at 20 h after the completion of trauma, hemorrhage, and resuscitation. Administration of the testosterone receptor blocker flutamide, however, significantly improved cardiac performance, HMBF, and hepatocellular function. Thus flutamide appears to be a novel and useful adjunct for improving cardiovascular and hepatocellular functions in males following trauma and hemorrhagic shock.

Does selective beta-1 blockade provide bone marrow protection after trauma/hemorrhagic shock?

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Pasupuleti, Latha V; Cook, Kristin M; Sifri, Ziad C; Kotamarti, Srinath; Calderon, Gabriel M; Alzate, Walter D; Livingston, David H; Mohr, Alicia M

2012-09-01

Previously, nonselective beta-blockade (BB) with propranolol demonstrated protection of the bone marrow (BM) after trauma and hemorrhagic shock (HS). Because selective beta-1 blockers are used commonly for their cardiac protection, the aim of this study was to more clearly define the role of specific beta adrenergic receptors in BM protection after trauma and HS. Male Sprague-Dawley rats underwent unilateral lung contusion (LC) followed by HS for 45 minutes. After resuscitation, animals were injected with a selective beta-blocker, atenolol (B1B), butoxamine (B2B), or SR59230A (B3B). Animals were killed at 3 hours or 7 days. Heart rate and blood pressure were measured throughout the study period. BM cellularity, growth of hematopoietic progenitor cells (HPCs) in BM, and hemoglobin levels (Hb) were assessed. Treatment with a B2B or B3B after LCHS restored both BM cellularity and BM HPC colony growth at 3 hours and 7 days. In contrast, treatment with a B1B had no effect on BM cellularity or HPC growth but did decrease heart effectively rate throughout the study. Treatment with a B3B after LCHS increased Hb as compared with LCHS alone. After trauma and HS, protection of BM for 7 days was seen with use of either a selective beta-2 or beta-3 blocker. Use of a selective beta-1 blocker was ineffective in protecting the BM despite a physiologic decrease in heart rate. Therefore, the protection of BM is via the beta-2 and beta-3 receptors and it is not via a direct cardiovascular effect. Published by Mosby, Inc.

The ACE-2/Ang1-7/Mas cascade enhances bone structure and metabolism following angiotensin-II type 1 receptor blockade.

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Abuohashish, Hatem M; Ahmed, Mohammed M; Sabry, Dina; Khattab, Mahmoud M; Al-Rejaie, Salim S

2017-07-15

The renin angiotensin system (RAS) regulates numerous systemic functions and is expressed locally in skeletal tissues. Angiotensin1-7 (Ang1-7) is a beneficial member of the RAS, and the therapeutic effects of a large number of angiotensin receptors blockers (ARBs) are mediated by an Ang1-7-dependent cascade. This study examines whether the reported osteo-preservative effects of losartan are mediated through the angiotensin converting enzyme2 (ACE-2)/Ang1-7/Mas pathway in ovariectomized (OVX) rats. Sham and OVX animals received losartan (10mg/kg/d p.o.) for 6 weeks. A specific Mas receptor blocker (A-779) was delivered via mini-osmotic pumps during the losartan treatment period. Serum and urine bone metabolism biomarker levels were measured. Bone trabecular and cortical morphometry were quantified in distal femurs, whereas mineral contents were estimated in ashed bones, serum and urine. Finally, the expression of RAS components, the receptor activator of NF-κB ligand (RANKL) and osteoprotegerin (OPG) was determined. Losartan significantly improved the elevated bone metabolism marker levels and altered trabecular and cortical structures in OVX animals, and restored normal urinary and skeletal mineral levels. Mas receptor inhibition significantly abolished all osteo-protective effects of losartan and enhanced the deleterious effects of OVX. Losartan enhanced OVX-induced up-regulation of ACE-1, AngII, angiotensin type 1 (AT 1 ) receptor and RANKL expression, and increased ACE-2, Ang1-7, Mas and OPG expression in OVX animals. However, A-779 significantly eradicated the effects of losartan on RAS components and RANKL/OPG expression. Thus, Ang1-7 are involved in the osteo-preservative effects of losartan via Mas receptor, which may add therapeutic value to this well-known antihypertensive agent. Copyright © 2017 Elsevier B.V. All rights reserved.

Blockade of the SNARE protein syntaxin 1 inhibits glioblastoma tumor growth.

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Fausto Ulloa

Full Text Available Glioblastoma (GBM is the most prevalent adult brain tumor, with virtually no cure, and with a median overall survival of 15 months from diagnosis despite of the treatment. SNARE proteins mediate membrane fusion events in cells and are essential for many cellular processes including exocytosis and neurotransmission, intracellular trafficking and cell migration. Here we show that the blockade of the SNARE protein Syntaxin 1 (Stx1 function impairs GBM cell proliferation. We show that Stx1 loss-of-function in GBM cells, through ShRNA lentiviral transduction, a Stx1 dominant negative and botulinum toxins, dramatically reduces the growth of GBM after grafting U373 cells into the brain of immune compromised mice. Interestingly, Stx1 role on GBM progression may not be restricted just to cell proliferation since the blockade of Stx1 also reduces in vitro GBM cell invasiveness suggesting a role in several processes relevant for tumor progression. Altogether, our findings indicate that the blockade of SNARE proteins may represent a novel therapeutic tool against GBM.

PCA3 Silencing Sensitizes Prostate Cancer Cells to Enzalutamide-mediated Androgen Receptor Blockade.

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Özgür, Emre; Celik, Ayca Iribas; Darendeliler, Emin; Gezer, Ugur

2017-07-01

Prostate cancer (PCa) is an androgen-dependent disease. Novel anti-androgens (i.e. enzalutamide) have recently been developed for the treatment of patients with metastatic castration-resistant prostate cancer (CRPC). Evidence is accumulating that prostate cancer antigen 3 (PCA3) is involved in androgen receptor (AR) signaling. Here, in combination with enzalutamide-mediated AR blockade, we investigated the effect of PCA3 targeting on the viability of PCa cells. In hormone-sensitive LNCaP cells, AR-overexpressing LNCaP-AR + cells and VCaP cells (representing CRPC), PCA3 was silenced using siRNA oligonucleotides. Gene expression and cell viability was assessed in PCA3-silenced and/or AR-blocked cells. PCA3 targeting reduced the expression of AR-related genes (i.e. prostate-specific antigen (PSA) and prostate-specific transcript 1 (non-protein coding) (PCGEM1)) and potentiated the effect of enzalutamide. Proliferation of PCa cells was suppressed upon PCA3 silencing with a greater effect in LNCaP-AR + cells. Furthermore, PCA3 silencing sensitized PCa cells to enzalutamide-induced loss of cell growth. PCA3, as a therapeutic target in PCa, might be used to potentiate AR antagonists. Copyright© 2017, International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.

Liberación de endotelina-1 por angiotensina ll en miocitos cardíacos aislados Angiotensin II-induced endothelin-1 release in cardiac myocytes

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María C. Villa-Abrille

2006-06-01

Full Text Available Muchos de los efectos de la angiotensina II (Ang II son mediados en realidad por la acción de endotelina (ET endógena liberada y/o producida en respuesta a la Ang II. En este trabajo evaluamos la interacción Ang II/ET-1, sus consecuencias en la contractilidad cardíaca y el papel de las especies reactivas del oxígeno (EROs. Se usaron cardiomiocitos aislados de gato. La Ang II, 1 nM, produjo un efecto inotrópico positivo (EIP de 31.8±3.8% que fue cancelado por inhibición de los receptores AT1, de los receptores de ET, del intercambiador Na+/H+ (NHE, del modo inverso del intercambiador Na+/Ca2+ (NCX o por el secuestro de EROs. La Ang II, 100 nM, produjo un EIP de 70.5±7.6% que fue cancelado por inhibición de los receptores AT1 y bloqueado en parte por inhibición de los receptores de ET, del NHE, del modo inverso del NCX o por el secuestro de EROs. La Ang II, 1 nM, incrementó el ARNm de la preproET-1 lo cual fue anulado por el bloqueo de los receptores AT1. Los resultados permiten concluir que el EIP de la Ang II es debido a la acción de la ET-1 endógena liberada/formada por la Ang II. La ET-1 produce: estimulación del NHE, activación del modo inverso del NCX y un consecuente EIP. Dentro de esta cascada también participarían los EROs.Many of the effects thought to be due to angiotensin II (Ang II are due to the release/formation of endothelin (ET. We tested whether Ang II elicits its positive inotropic effect (PIE by the action of endogenous ET-1 and the role played by the reactive oxygen species (ROS in this mechanism. Experiments were performed in cat isolated ventricular myocytes in which sarcomere shortening (SS was measured to asses contractility after pharmacological interventions and the effect of Ang II on inotropism were analyzed. Ang II 1 nM increased SS by 31.8±3.8% (p<0.05. This PIE was cancelled by AT1 receptor blockade, by ET-1 receptors blockade, by Na+/H+ exchanger (NHE inhibition, by reverse mode Na+/Ca2

Expression analysis and specific blockade of the receptor for human thymic stromal lymphopoietin (TSLP) by novel antibodies to the human TSLPRα receptor chain.

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Borowski, Andreas; Vetter, Tina; Kuepper, Michael; Wohlmann, Andreas; Krause, Sebastian; Lorenzen, Thomas; Virchow, Johann Christian; Luttmann, Werner; Friedrich, Karlheinz

2013-02-01

Thymic stromal lymphopoietin (TSLP) is an interleukin-7 (IL-7)-like cytokine with a pivotal role in development and maintenance of atopic diseases such as allergic asthma and atopic dermatitis. Moreover, recent studies show an involvement of TSLP in the progression of various cancers. TSLP signaling is mediated by the TSLP receptor (TSLPR), a heterodimeric type I cytokine receptor. It consists of the IL-7 receptor alpha chain (IL-7Rα), which is shared with the IL-7 receptor, and the TSLPRα chain as a specific subunit. Blocking signal release by TSLP without affecting IL-7 function is a potentially interesting option for the treatment of atopic diseases or certain tumors. By employing the extracellular domain of human TSLPRα chain (hTSLPRα(ex)) as an antigen, we generated a set of monoclonal antibodies. Several binders to native and/or denatured receptor protein were identified and characterized by cytometry and Western blot analysis. A screen based on a STAT3-driven reporter gene assay in murine pro-B cells expressing a functional hTSLPR yielded two hybridoma clones with specific antagonistic properties towards hTSLP, but not IL-7. Kinetic studies measuring blockade of hTSLP-dependent STAT phosphorylation in a TSLP-responsive cell line revealed an inhibitory constant in the nanomolar range. Copyright © 2012 Elsevier Ltd. All rights reserved.

Sodium intake, RAAS-blockade and progressive renal disease

NARCIS (Netherlands)

de Borst, Martin H; Navis, Gerjan

Pharmacological blockade of the renin-angiotensin-aldosterone system (RAAS) by angiotensin converting enzyme inhibitors or angiotensin receptor blockers is the current standard treatment to prevent progressive renal function loss in patients with chronic kidney disease. Yet in many patients the

Histamine delays gastric emptying of solid food in man through histamine, receptors

International Nuclear Information System (INIS)

Sridhar, K.; Lange, R.; McCallum, R.W.

1984-01-01

The authors have shown that histamine (H) contracts the cat pylorus and duodenum through H/sub 1/ receptor mechanisms. The authors investigated the effect of H infusion on gastric emptying (GE) and the role of H/sub 1/ and H/sub 2/ receptor blockade in healthy volunteers. Radionuclide GE studies were performed using chicken liver labeled in vivo with /sup 99m/Technetium-sulfur colloid as a marker of solid food. Study days were as follows: a baseline GE study (Day 1); H infused continuously IV at a rate of 40 μg/kg/hr during the GE study (Day 2); an IV bolus of 50 mg of diphenhydramine (Day 3), or 300 mg cimetidine (Day 4) given just prior to the continuous infusion of H; a final day when cimetidine was given alone (Day 5). GE was monitored for 2 hours on each day. The results of days 1, 2 and 3 are summarized below (+p<0.05 vs baseline or Day 1). Pretreatment with cimetidine (Day 4) augmented the delay in GE induced by H infusion, while cimetidine without H (Day 5) had no effect on GE. The authors conclude that: 1) H given at a dose which elicits maximal acid secretory response in man significantly delays GE; and 2) H/sub 1/ receptor blockade but not H/sub 2/ blockade prevented this effect. Histamine may play a modulatory role in human gastric emptying through an H/sub 1/ receptor mechanism

5HT2A receptor blockade in dorsomedial striatum reduces repetitive behaviors in BTBR mice.

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Amodeo, D A; Rivera, E; Cook, E H; Sweeney, J A; Ragozzino, M E

2017-03-01

Restricted and repetitive behaviors are a defining feature of autism, which can be expressed as a cognitive flexibility deficit or stereotyped, motor behaviors. There is limited knowledge about the underlying neuropathophysiology contributing to these behaviors. Previous findings suggest that central 5HT 2A receptor activity is altered in autism, while recent work indicates that systemic 5HT 2A receptor antagonist treatment reduces repetitive behaviors in an idiopathic model of autism. 5HT 2A receptors are expressed in the orbitofrontal cortex and striatum. These two regions have been shown to be altered in autism. The present study investigated whether 5HT 2A receptor blockade in the dorsomedial striatum or orbitofrontal cortex in the BTBR mouse strain, an idiopathic model of autism, affects the phenotype related to restricted and repetitive behaviors. Microinfusion of the 5HT 2A receptor antagonist, M100907 into the dorsomedial striatum alleviated a reversal learning impairment and attenuated grooming behavior. M100907 infusion into the orbitofrontal cortex increased perseveration during reversal learning and potentiated grooming. These findings suggest that increased 5HT 2A receptor activity in the dorsomedial striatum may contribute to behavioral inflexibility and stereotyped behaviors in the BTBR mouse. 5HT 2A receptor signaling in the orbitofrontal cortex may be critical for inhibiting a previously learned response during reversal learning and expression of stereotyped behavior. The present results suggest which brain areas exhibit abnormalities underlying repetitive behaviors in an idiopathic mouse model of autism, as well as which brain areas systemic treatment with M100907 may principally act on in BTBR mice to attenuate repetitive behaviors. © 2016 John Wiley & Sons Ltd and International Behavioural and Neural Genetics Society.

Enhancement of cortical extracellular 5-HT by 5-HT1A and 5-HT2C receptor blockade restores the antidepressant-like effect of citalopram in non-responder mice.

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Calcagno, Eleonora; Guzzetti, Sara; Canetta, Alessandro; Fracasso, Claudia; Caccia, Silvio; Cervo, Luigi; Invernizzi, Roberto W

2009-07-01

We recently found that the response of DBA/2 mice to SSRIs in the forced swim test (FST) was impaired and they also had a smaller basal and citalopram-stimulated increase in brain extracellular serotonin (5-HT) than 'responder' strains. We employed intracerebral microdialysis, FST and selective antagonists of 5-HT1A and 5-HT2C receptors to investigate whether enhancing the increase in extracellular 5-HT reinstated the anti-immobility effect of citalopram in the FST. WAY 100635 (0.3 mg/kg s.c.) or SB 242084 (1 mg/kg s.c.), respectively a selective 5-HT1A and 5-HT2C receptor antagonist, raised the effect of citalopram (5 mg/kg) on extracellular 5-HT in the medial prefrontal cortex of DBA/2N mice (citalopram alone 5.2+/-0.3 fmol/20 microl, WAY 100635+citalopram 9.9+/-2.1 fmol/20 microl, SB 242084+ citalopram 7.6+/-1.0 fmol/20 microl) to the level reached in 'responder' mice given citalopram alone. The 5-HT receptor antagonists had no effect on the citalopram-induced increase in extracellular 5-HT in the dorsal hippocampus. The combination of citalopram with WAY 100635 or SB 242084 significantly reduced immobility time in DBA/2N mice that otherwise did not respond to either drug singly. Brain levels of citalopram in mice given citalopram alone or with 5-HT antagonists did not significantly differ. The results confirm that impaired 5-HT transmission accounts for the lack of effect of citalopram in the FST and suggest that enhancing the effect of SSRIs on extracellular 5-HT, through selective blockade of 5-HT1A and 5-HT2C receptors, could be a useful strategy to restore the response in treatment-resistant depression.

Why not treat human cancer with interleukin-1 blockade?

NARCIS (Netherlands)

Dinarello, C.A.

2010-01-01

The clinical successes of targeting angiogenesis provide a basis for trials of interleukin-1 (IL-1) blockade and particularly anti-IL-1beta as an add-on therapy in human metastatic disease. In animal studies for over 20 years, IL-1 has been demonstrated to increase adherence of tumor cells to the

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

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Zhang, Yuanyuan; Yuan, Fahuan; Cao, Xuejiao [Department of Nephrology, Xinqiao Hospital, PLA, Third Military Medical University, Chongqing 400037 (China); Zhai, Zhifang [Department of Dermatology, Southwest Hospital, Third Military Medical University, Chongqing 400038 (China); Gang Huang [Department of Medical Genetics, Third Military Medical University, Chongqing 430038 (China); Du, Xiang; Wang, Yiqin; Zhang, Jingbo; Huang, Yunjian; Zhao, Jinghong [Department of Nephrology, Xinqiao Hospital, PLA, Third Military Medical University, Chongqing 400037 (China); Hou, Weiping, E-mail: hwp0518@aliyun.com [Department of Nephrology, Xinqiao Hospital, PLA, Third Military Medical University, Chongqing 400037 (China)

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

VEGF blockade inhibits angiogenesis and reepithelialization of endometrium.

Science.gov (United States)

Fan, Xiujun; Krieg, Sacha; Kuo, Calvin J; Wiegand, Stanley J; Rabinovitch, Marlene; Druzin, Maurice L; Brenner, Robert M; Giudice, Linda C; Nayak, Nihar R

2008-10-01

Despite extensive literature on vascular endothelial growth factor (VEGF) expression and regulation by steroid hormones, the lack of clear understanding of the mechanisms of angiogenesis in the endometrium is a major limitation for use of antiangiogenic therapy targeting endometrial vessels. In the current work, we used the rhesus macaque as a primate model and the decidualized mouse uterus as a murine model to examine angiogenesis during endometrial breakdown and regeneration. We found that blockade of VEGF action with VEGF Trap, a potent VEGF blocker, completely inhibited neovascularization during endometrial regeneration in both models but had no marked effect on preexisting or newly formed vessels, suggesting that VEGF is essential for neoangiogenesis but not survival of mature vessels in this vascular bed. Blockade of VEGF also blocked reepithelialization in both the postmenstrual endometrium and the mouse uterus after decidual breakdown, evidence that VEGF has pleiotropic effects in the endometrium. In vitro studies with a scratch wound assay showed that the migration of luminal epithelial cells during repair involved signaling through VEGF receptor 2-neuropilin 1 (VEGFR2-NP1) receptors on endometrial stromal cells. The leading front of tissue growth during endometrial repair was strongly hypoxic, and this hypoxia was the local stimulus for VEGF expression and angiogenesis in this tissue. In summary, we provide novel experimental data indicating that VEGF is essential for endometrial neoangiogenesis during postmenstrual/postpartum repair.

Frontal fasciculi and psychotic symptoms in antipsychotic-naive patients with schizophrenia before and after 6 weeks of selective dopamine D2/3 receptor blockade

DEFF Research Database (Denmark)

Ebdrup, Bjørn H; Raghava, Jayachandra M; Nielsen, Mette Ødegaard

2016-01-01

/3 receptor blockade would restore white matter. METHODS: Between December 2008 and July 2011, antipsychotic-naive patients with first-episode schizophrenia and matched healthy controls underwent baseline examination with 3 T MRI diffusion tensor imaging and clinical assessments. We assessed group differences...... with first-episode schizophrenia and 38 controls in our analysis, and 28 individuals in each group completed the study. At baseline, whole brain TBSS analyses revealed lower FA in patients in the right anterior thalamic radiation (ATR), right cingulum, right inferior longitudinal fasciculus and right...

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

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Tahereh Safari

2013-01-01

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.

Endocannabinoid receptor blockade increases vascular endothelial growth factor and inflammatory markers in obese women with polycystic ovary syndrome.

Science.gov (United States)

Sathyapalan, Thozhukat; Javed, Zeeshan; Kilpatrick, Eric S; Coady, Anne-Marie; Atkin, Stephen L

2017-03-01

Animal studies suggest that cannabinoid receptor-1 (CB-1) blockade reduces inflammation and neovascularization by decreasing vascular endothelial growth factor (VEGF) levels associated with a reduction in inflammatory markers, thereby potentially reducing cardiovascular risk. To determine the impact of CB1 antagonism by rimonabant on VEGF and inflammatory markers in obese PCOS women. Randomized, open-labelled parallel study. Endocrinology outpatient clinic in a referral centre. Twenty patients with PCOS (PCOS) and biochemical hyperandrogenaemia with a body mass index of ≥30 kg/m 2 were recruited. Patients were randomized to 1·5 g daily of metformin or 20 mg daily of rimonabant. Post hoc review to detect VEGF and pro-inflammatory cytokines TNF-α, IL-1β, IL-1ra, IL-2, IL6, IL-8, IL-10 and MCP-1 before and after 12 weeks of treatment. After 12 weeks of rimonabant treatment, there was a significant increase in VEGF (99·2 ± 17·6 vs 116·2 ± 15·8 pg/ml, P weight loss. © 2016 John Wiley & Sons Ltd.

Therapeutic PD-L1 and LAG-3 blockade rapidly clears established blood-stage Plasmodium infection

Science.gov (United States)

Butler, Noah S.; Moebius, Jacqueline; Pewe, Lecia L.; Traore, Boubacar; Doumbo, Ogobara K.; Tygrett, Lorraine T.; Waldschmidt, Thomas J.; Crompton, Peter D.; Harty, John T.

2011-01-01

Plasmodium infection of erythrocytes induces clinical malaria. Parasite-specific CD4+ T cells correlate with reduced parasite burdens and severity of human malaria, and are required to control blood-stage infection in mice. However, the characteristics of CD4+ T cells that determine protection or parasite persistence remain unknown. Here we show that P. falciparum infection of humans increased expression of an inhibitory receptor (PD-1) associated with T cell dysfunction. In vivo blockade of PD-L1 and LAG-3 restored CD4+ T cell function, amplified T follicular helper cell and germinal center B cell and plasmablast numbers, enhanced protective antibodies and rapidly cleared blood-stage malaria in mice. Thus, chronic malaria drives specific T cell dysfunction, which can be rescued to enhance parasite control using inhibitory therapies. PMID:22157630

Pilocarpine-Induced Status Epilepticus Increases the Sensitivity of P2X7 and P2Y1 Receptors to Nucleotides at Neural Progenitor Cells of the Juvenile Rodent Hippocampus.

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Rozmer, Katalin; Gao, Po; Araújo, Michelle G L; Khan, Muhammad Tahir; Liu, Juan; Rong, Weifang; Tang, Yong; Franke, Heike; Krügel, Ute; Fernandes, Maria José S; Illes, Peter

2017-07-01

Patch-clamp recordings indicated the presence of P2X7 receptors at neural progenitor cells (NPCs) in the subgranular zone of the dentate gyrus in hippocampal brain slices prepared from transgenic nestin reporter mice. The activation of these receptors caused inward current near the resting membrane potential of the NPCs, while P2Y1 receptor activation initiated outward current near the reversal potential of the P2X7 receptor current. Both receptors were identified by biophysical/pharmacological methods. When the brain slices were prepared from mice which underwent a pilocarpine-induced status epilepticus or when brain slices were incubated in pilocarpine-containing external medium, the sensitivity of P2X7 and P2Y1 receptors was invariably increased. Confocal microscopy confirmed the localization of P2X7 and P2Y1 receptor-immunopositivity at nestin-positive NPCs. A one-time status epilepticus in rats caused after a latency of about 5 days recurrent epileptic fits. The blockade of central P2X7 receptors increased the number of seizures and their severity. It is hypothesized that P2Y1 receptors after a status epilepticus may increase the ATP-induced proliferation/ectopic migration of NPCs; the P2X7 receptor-mediated necrosis/apoptosis might counteract these effects, which would otherwise lead to a chronic manifestation of recurrent epileptic fits. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Recovery of NMDA receptor currents from MK-801 blockade is accelerated by Mg2+ and memantine under conditions of agonist exposure

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McKay, Sean; Bengtson, C. Peter; Bading, Hilmar; Wyllie, David J.A.; Hardingham, Giles E.

2013-01-01

MK-801 is a use-dependent NMDA receptor open channel blocker with a very slow off-rate. These properties can be exploited to ‘pre-block’ a population of NMDARs, such as synaptic ones, enabling the selective activation of a different population, such as extrasynaptic NMDARs. However, the usefulness of this approach is dependent on the stability of MK-801 blockade after washout. We have revisited this issue, and confirm that recovery of NMDAR currents from MK-801 blockade is enhanced by channel opening by NMDA, and find that it is further increased when Mg2+ is also present. In the presence of Mg2+, 50% recovery from MK-801 blockade is achieved after 10′ of 100 μM NMDA, or 30′ of 15 μM NMDA exposure. In Mg2+-free medium, NMDA-induced MK-801 dissociation was found to be much slower. Memantine, another PCP-site antagonist, could substitute for Mg2+ in accelerating the unblock of MK-801 in the presence of NMDA. This suggests a model whereby, upon dissociation from its binding site in the pore, MK-801 is able to re-bind in a process antagonized by Mg2+ or another PCP-site antagonist. Finally we show that even when all NMDARs are pre-blocked by MK-801, incubation of neurons with 100 μM NMDA in the presence of Mg2+ for 2.5 h triggers sufficient unblocking to kill >80% of neurons. We conclude that while synaptic MK-801 ‘pre-block’ protocols are useful for pharmacologically assessing synaptic vs. extrasynaptic contributions to NMDAR currents, or studying short-term effects, it is problematic to use this technique to attempt to study the effects of long-term selective extrasynaptic NMDAR activation. This article is part of the Special Issue entitled ‘Glutamate Receptor-Dependent Synaptic Plasticity’. PMID:23402996

Acute cannabinoids impair working memory through astroglial CB1 receptor modulation of hippocampal LTD.

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Han, Jing; Kesner, Philip; Metna-Laurent, Mathilde; Duan, Tingting; Xu, Lin; Georges, Francois; Koehl, Muriel; Abrous, Djoher Nora; Mendizabal-Zubiaga, Juan; Grandes, Pedro; Liu, Qingsong; Bai, Guang; Wang, Wei; Xiong, Lize; Ren, Wei; Marsicano, Giovanni; Zhang, Xia

2012-03-02

Impairment of working memory is one of the most important deleterious effects of marijuana intoxication in humans, but its underlying mechanisms are presently unknown. Here, we demonstrate that the impairment of spatial working memory (SWM) and in vivo long-term depression (LTD) of synaptic strength at hippocampal CA3-CA1 synapses, induced by an acute exposure of exogenous cannabinoids, is fully abolished in conditional mutant mice lacking type-1 cannabinoid receptors (CB(1)R) in brain astroglial cells but is conserved in mice lacking CB(1)R in glutamatergic or GABAergic neurons. Blockade of neuronal glutamate N-methyl-D-aspartate receptors (NMDAR) and of synaptic trafficking of glutamate α-amino-3-hydroxy-5-methyl-isoxazole propionic acid receptors (AMPAR) also abolishes cannabinoid effects on SWM and LTD induction and expression. We conclude that the impairment of working memory by marijuana and cannabinoids is due to the activation of astroglial CB(1)R and is associated with astroglia-dependent hippocampal LTD in vivo. Copyright © 2012 Elsevier Inc. All rights reserved.

Blockade of KCa3.1 Attenuates Left Ventricular Remodeling after Experimental Myocardial Infarction

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Chen-Hui Ju

2015-07-01

Full Text Available Background/Aims: After myocardial infarction (MI, cardiac fibrosis greatly contributes to left ventricular remodeling and heart failure. The intermediate-conductance calcium-activated potassium Channel (KCa3.1 has been recently proposed as an attractive target of fibrosis. The present study aimed to detect the effects of KCa3.1 blockade on ventricular remodeling following MI and its potential mechanisms. Methods: Myocardial expression of KCa3.1 was initially measured in a mouse MI model by Western blot and real time-polymerase chain reaction. Then after treatment with TRAM-34, a highly selective KCa3.1 blocker, heart function and fibrosis were evaluated by echocardiography, histology and immunohistochemistry. Furthermore, the role of KCa3.1 in neonatal mouse cardiac fibroblasts (CFs stimulated by angiotensin II (Ang II was tested. Results: Myocardium expressed high level of KCa3.1 after MI. Pharmacological blockade of KCa3.1 channel improved heart function and reduced ventricular dilation and fibrosis. Besides, a lower prevalence of myofibroblasts was found in TRAM-34 treatment group. In vitro studies KCa3.1 was up regulated in CFs induced by Ang II and suppressed by its blocker.KCa3.1 pharmacological blockade attenuated CFs proliferation, differentiation and profibrogenic genes expression and may regulating through AKT and ERK1/2 pathways. Conclusion: Blockade of KCa3.1 is able to attenuate ventricular remodeling after MI through inhibiting the pro-fibrotic effects of CFs.

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.

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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.

Progesterone receptor blockade in human breast cancer cells decreases cell cycle progression through G2/M by repressing G2/M genes

OpenAIRE

Clare, Susan E.; Gupta, Akash; Choi, MiRan; Ranjan, Manish; Lee, Oukseub; Wang, Jun; Ivancic, David Z.; Kim, J. Julie; Khan, Seema A.

2016-01-01

Background The synthesis of specific, potent progesterone antagonists adds potential agents to the breast cancer prevention and treatment armamentarium. The identification of individuals who will benefit from these agents will be a critical factor for their clinical success. Methods We utilized telapristone acetate (TPA; CDB-4124) to understand the effects of progesterone receptor (PR) blockade on proliferation, apoptosis, promoter binding, cell cycle progression, and gene expression. We then...

Interleukin-7 receptor blockade suppresses adaptive and innate inflammatory responses in experimental colitis

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Willis Cynthia R

2012-10-01

Full Text Available Abstract Background Interleukin-7 (IL-7 acts primarily on T cells to promote their differentiation, survival, and homeostasis. Under disease conditions, IL-7 mediates inflammation through several mechanisms and cell types. In humans, IL-7 and its receptor (IL-7R are increased in diseases characterized by inflammation such as atherosclerosis, rheumatoid arthritis, psoriasis, multiple sclerosis, and inflammatory bowel disease. In mice, overexpression of IL-7 results in chronic colitis, and T-cell adoptive transfer studies suggest that memory T cells expressing high amounts of IL-7R drive colitis and are maintained and expanded with IL-7. The studies presented here were undertaken to better understand the contribution of IL-7R in inflammatory bowel disease in which colitis was induced with a bacterial trigger rather than with adoptive transfer. Methods We examined the contribution of IL-7R on inflammation and disease development in two models of experimental colitis: Helicobacter bilis (Hb-induced colitis in immune-sufficient Mdr1a−/− mice and in T- and B-cell-deficient Rag2−/− mice. We used pharmacological blockade of IL-7R to understand the mechanisms involved in IL-7R-mediated inflammatory bowel disease by analyzing immune cell profiles, circulating and colon proteins, and colon gene expression. Results Treatment of mice with an anti-IL-7R antibody was effective in reducing colitis in Hb-infected Mdr1a−/− mice by reducing T-cell numbers as well as T-cell function. Down regulation of the innate immune response was also detected in Hb-infected Mdr1a−/− mice treated with an anti-IL-7R antibody. In Rag2−/− mice where colitis was triggered by Hb-infection, treatment with an anti-IL-7R antibody controlled innate inflammatory responses by reducing macrophage and dendritic cell numbers and their activity. Conclusions Results from our studies showed that inhibition of IL-7R successfully ameliorated inflammation and disease development

The roles of complement receptors type 1 (CR1, CD35) and type 3 (CR3, CD11b/CD18) in the regulation of the immune complex-elicited respiratory burst of polymorphonuclear leukocytes in whole blood

DEFF Research Database (Denmark)

Nielsen, C H; Antonsen, S; Matthiesen, S H

1997-01-01

The binding of immune complexes (IC) to polymorphonuclear leukocytes (PMN) and the consequent respiratory burst (RB) were investigated in whole blood cell preparations suspended in 75% human serum, using flow cytometry. Blockade of the complement receptor (CR)1 receptor sites for C3b on whole blood...... cells using the monoclonal antibody (mAb) 3D9 resulted in a 1.9-fold increase in the IC-elicited PMN RB after 5 min of incubation, rising to 3.1-fold after 40 min. This enhancement was not due to increased IC deposition on PMN. Blockade of CR3 abrogated the mAb 3D9-induced rise in RB activity...

Combined blockade of vascular endothelial growth factor and programmed death 1 pathways in advanced kidney cancer.

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Einstein, David J; McDermott, David F

2017-06-01

Targeted and immune-based therapies have improved outcomes in advanced kidney cancer, yet novel strategies are needed to extend the duration of these benefits and expand them to more patients. Combined inhibition of vascular endothelial growth factor (VEGF) and the programmed death 1 (PD-1)/programmed death ligand 1 (PD-L1) pathways with therapeutic agents already in clinical use may offer such a strategy. Here, we describe the development and clinical evaluation of VEGF inhibitors and, separately, PD-1/PD-L1 inhibitors. We present preclinical evidence of interaction between these pathways and the rationale for combined blockade. Beyond well-known effects on pathologic angiogenesis, VEGF blockade also may decrease immune tolerance and enhance PD-1/PD-L1 blockade. We conclude with the results of several early trials of combined VEGF and PD-1/PD-L1 blockade, which demonstrate encouraging antitumor activity, and we pose questions for future study.

Involvement of norepinephrine activity in the regulation of α1 adrenergic receptors in the medial preoptic nucleus of estradiol-treated rats

International Nuclear Information System (INIS)

Sortino, M.A.; Weiland, N.G.; Wise, P.M.

1989-01-01

To establish whether the diurnal decrease in the density of α1 receptors observed in the medial preoptic nucleus (MPN) of estrogen (E 2 )-treated rats is related to the concomitant diurnal increase in norepinephrine (NE) turnover rates, we quantitiated the density of [ 3 H]-Prazosin binding to α1 receptors after blockade of NE turnover with alpha-methyl-paratyrosine (αMPT). A series of preliminary studies was performed to rule out an interference of this drug with [ 3 H]-Prazosin binding to α1 adrenergic receptors in vitro and in vivo. Incubation of brain slices with αMPT produced a dose-dependent inhibition of [ 3 H]-Prazosin binding to α1 adrenergic receptors with an IC 50 of approximately 6 mM. Scatchard analysis demonstrated that αMPT exhibited a simple competitive interaction with [ 3 H]-Prazosin binding sites as shown by an increase in the apparent dissociation constant (Kd) of the ligand and no change in the number of α1 receptors (B/sub max/). In contrast, preincubation of brain slices with αMPT and prior in vivo administration of αMPT did not affect [ 3 H]-Prazosin binding to α1 adrenergic receptors. The density of α1 adrenergic receptors in MPN was quantitated autoradiographically. Blockade of NE turnover with αMPT only partially prevented the reduction in α1 receptor density observed in the E 2 -treated rats, suggesting that the decrease in the level of [ 3 H]-Prazosin binding sites cannot be completely ascribed to increased NE turnover rates

Role of lateral septum glucagon-like peptide 1 receptors in food intake.

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Terrill, Sarah J; Jackson, Christine M; Greene, Hayden E; Lilly, Nicole; Maske, Calyn B; Vallejo, Samantha; Williams, Diana L

2016-07-01

Hindbrain glucagon-like peptide 1 (GLP-1) neurons project to numerous forebrain areas, including the lateral septum (LS). Using a fluorescently labeled GLP-1 receptor (GLP-1R) agonist, Exendin 4 (Ex4), we demonstrated GLP-1 receptor binding throughout the rat LS. We examined the feeding effects of Ex4 and the GLP-1R antagonist Exendin (9-39) (Ex9) at doses subthreshold for effect when delivered to the lateral ventricle. Intra-LS Ex4 suppressed overnight chow and high-fat diet (HFD) intake, and Ex9 increased chow and HFD intake relative to vehicle. During 2-h tests, intra-LS Ex9 significantly increased 0.25 M sucrose and 4% corn oil. Ex4 can cause nausea, but intra-LS administration of Ex4 did not induce pica. Furthermore, intra-LS Ex4 had no effect on anxiety-like behavior in the elevated plus maze. We investigated the role of LS GLP-1R in motivation for food by examining operant responding for sucrose on a progressive ratio (PR) schedule, with and without a nutrient preload to maximize GLP-1 neuron activation. The preload strongly suppressed PR responding, but blockade of GLP-1R in the intermediate subdivision of the LS did not affect motivation for sucrose under either load condition. The ability of the nutrient load to suppress subsequent chow intake was significantly attenuated by intermediate LS Ex9 treatment. By contrast, blockade of GLP-1R in the dorsal subdivision of the LS increased both PR responding and overnight chow intake. Together, these studies suggest that endogenous activity of GLP-1R in the LS influence feeding, and dLS GLP-1Rs, in particular, play a role in motivation. Copyright © 2016 the American Physiological Society.

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

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Vivian V. Costa

2017-04-01

Full Text Available 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.

Selective pharmacological blockade of the 5-HT7 receptor attenuates light and 8-OH-DPAT induced phase shifts of mouse circadian wheel running activity

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Jonathan eShelton

2015-01-01

Full Text Available Recent reports have illustrated a reciprocal relationship between circadian rhythm disruption and mood disorders. The 5-HT7 receptor may provide a crucial link between the two sides of this equation since the receptor plays a critical role in sleep, depression, and circadian rhythm regulation. To further define the role of the 5-HT7 receptor as a potential pharmacotherapy to correct circadian rhythm disruptions, the current study utilized the selective 5-HT7 antagonist JNJ-18038683 (10 mg/kg in three different circadian paradigms. While JNJ-18038683 was ineffective at phase shifting the onset of wheel running activity in mice when administered at different circadian time (CT points across the circadian cycle, pretreatment with JNJ-18038683 blocked non-photic phase advance (CT6 induced by the 5-HT1A/7 receptor agonist 8-OH-DPAT (3 mg/kg. Since light induced phase shifts in mammals are partially mediated via the modulation of the serotonergic system, we determined if JNJ-18038683 altered phase shifts induced by a light pulse at times known to phase delay (CT15 or advance (CT22 wheel running activity in free running mice. Light exposure resulted in a robust shift in the onset of activity in vehicle treated animals at both times tested. Administration of JNJ-18038683 significantly attenuated the light-induced phase delay and completely blocked the phase advance. The current study demonstrates that pharmacological blockade of the 5-HT7 receptor by JNJ-18038683 blunts both non-photic and photic phase shifts of circadian wheel running activity in mice. These findings highlight the importance of the 5-HT7 receptor in modulating circadian rhythms. Due to the opposite modulating effects of light resetting between diurnal and nocturnal species, pharmacotherapy targeting the 5-HT7 receptor in conjunction with bright light therapy may prove therapeutically beneficial by correcting the desynchronization of internal rhythms observed in depressed individuals.

Effect of Angiotensin II Type I Receptor Blockade with Valsartan on Carotid Artery Atherosclerosis: A Double Blind Randomized Clinical Trial Comparing Valsartan and Placebo (EFFERVESCENT).

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Ramadan, Ronnie; Dhawan, Saurabh S; Binongo, José Nilo G; Alkhoder, Ayman; Jones, Dean P; Oshinski, John N; Quyyumi, Arshed A

2016-04-01

Progression of atherosclerosis is associated with a greater risk for adverse outcomes. Angiotensin II plays a key role in the pathogenesis and progression of atherosclerosis. We aimed to investigate the effects of angiotensin II type-1 receptor blockade with Valsartan on carotid wall atherosclerosis, with the hypothesis that Valsartan will reduce progression of atherosclerosis. Subjects (n = 120) with carotid intima-media thickness >0.65 mm by ultrasound were randomized (2:1) in a double-blind manner to receive either Valsartan or placebo for 2 years. Bilateral T2-weighted black-blood carotid magnetic resonance imaging was performed at baseline, 12 and 24 months. Changes in the carotid bulb vessel wall area and wall thickness were primary endpoints. Secondary endpoints included changes in carotid plaque thickness, plasma levels of aminothiols, C-reactive protein, fibrinogen, and endothelium-dependent and -independent vascular function. Over 2 years, the carotid bulb vessel wall area decreased with Valsartan (-6.7, 95% CI [-11.6, -1.9] mm(2)) but not with placebo (3.4, 95% CI [-2.8, 9.6] mm(2)), P = .01 between groups. Similarly, mean wall thickness decreased with Valsartan (-0.18, 95% CI [-0.30, -0.06] mm), but not with placebo (0.08, 95% CI [-0.07, 0.23] mm), P = .009 between groups. Furthermore, plaque thickness decreased with Valsartan (-0.35, 95% CI [-0.63, -0.08] mm) but was unchanged with placebo (+0.28, 95% CI [-0.11, 0.69] mm), P = .01 between groups. These findings were unaffected by statin therapy or changes in blood pressure. Notably, there were significant improvements in the aminothiol cysteineglutathione disulfide, and trends to improvements in fibrinogen levels and endothelium-independent vascular function. In subjects with carotid wall thickening, angiotensin II type-1 receptor blockade was associated with regression in carotid atherosclerosis. Whether these effects translate into improved outcomes in subjects with subclinical atherosclerosis

Why CCR2 and CCR5 blockade failed and why CCR1 blockade might still be effective in the treatment of rheumatoid arthritis

OpenAIRE

Lebre, M.C.; Vergunst, C.E.; Choi, I.Y.K.; Aarrass, S.; Oliveira, A.S.F.; Wyant, T.; Horuk, R.; Reedquist, K.A.; Tak, P.P.

2011-01-01

BACKGROUND: The aim of this study was to provide more insight into the question as to why blockade of CCR1, CCR2, and CCR5 may have failed in clinical trials in rheumatoid arthritis (RA) patients, using an in vitro monocyte migration system model. METHODOLOGY/PRINCIPAL FINDINGS: Monocytes from healthy donors (HD; n = 8) or from RA patients (for CCR2 and CCR5 antibody n = 8; for CCR1 blockade n = 13) were isolated from peripheral blood and pre-incubated with different concentrations of either ...

Receptor-independent, vacuolar ATPase-mediated cellular uptake of histamine receptor-1 ligands: Possible origin of pharmacological distortions and side effects

International Nuclear Information System (INIS)

Morissette, Guillaume; Lodge, Robert; Bouthillier, Johanne; Marceau, Francois

2008-01-01

The aims of this study were to investigate whether several histamine receptor agonists and antagonists are subjected to receptor-independent ion trapping into acidic organelles, and whether this sequestration influences their pharmacological or toxicological properties. Vacuolar (V)-ATPase-dependent intracellular sequestration of agonists was recognized as morphological alterations (large fluid-filled vacuoles for betahistine and 1-methylhistamine, granular uptake for fluorescent BODIPY FL histamine) prevented by the specific V-ATPase inhibitor bafilomycin A1 in rabbit vascular smooth muscle cells. Lipophilicity was the major determinant of these cellular effects (order of potency: BODIPY FL histamine > betahistine > 1-methylhistamine > histamine) that occurred at high concentrations. This ranking was dissociable from the potency order for H 1 receptor-mediated contraction of the rabbit aorta, a response uninfluenced by bafilomycin. Antihistamines are inherently more lipophilic and caused vacuolization of a proportion of cells at 5-500 μM. Agonist or antagonist-induced vacuoles were of macroautophagic nature (labeled with GFP-conjugated LC3, Rab7 and CD63; detection of LC3 II). Further, the 2 most lipophilic antihistamines tested, astemizole and terfenadine, were potentiated by V-ATPase blockade in the aortic contractility assay (13- and 3.6-fold more potent, respectively, pA 2 scale), suggesting that V-ATPase-mediated cation trapping sequesters these antagonists from the vicinity of H 1 receptors in the therapeutic concentration range. This potentiation did not apply to less lipophilic antagonists (pyrilamine, diphenhydramine). While some agonists and all tested antagonists of the histamine H 1 receptors induce the V-ATPase-dependent vacuolar and autophagic cytopathology, sequestration affects the pharmacology of only the most lipophilic antagonists, the ones prone to off-target arrhythmogenic side effects

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

Science.gov (United States)

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

Pharmacological and biochemical characterization of the D-1 dopamine receptor mediating acetylcholine release in rabbit retina

International Nuclear Information System (INIS)

Hensler, J.G.; Cotterell, D.J.; Dubocovich, M.L.

1987-01-01

Superfusion with dopamine (0.1 microM-10 mM) evokes calcium-dependent [ 3 H]acetylcholine release from rabbit retina labeled in vitro with [ 3 H]choline. This effect is antagonized by the D-1 dopamine receptor antagonist SCH 23390. Activation or blockade of D-2 dopamine, alpha-2 or beta receptors did not stimulate or attenuate the release of [ 3 H]acetylcholine from rabbit retina. Dopamine receptor agonists evoke the release of [ 3 H]acetylcholine with the following order of potency: apomorphine ≤ SKF(R)82526 3 H]acetylcholine: SCH 23390 (IC50 = 1 nM) 3 H]acetylcholine release is characteristic of the D-1 dopamine receptor. These potencies were correlated with the potencies of dopamine receptor agonists and antagonists at the D-1 dopamine receptor in rabbit retina as labeled by [ 3 H]SCH 23390, or as determined by adenylate cyclase activity. [ 3 H]SCH 23390 binding in rabbit retinal membranes was stable, saturable and reversible. Scatchard analysis of [ 3 H]SCH 23390 saturation data revealed a single high affinity binding site (Kd = 0.175 +/- 0.002 nM) with a maximum binding of 482 +/- 12 fmol/mg of protein. The potencies of dopamine receptor agonists to stimulate [ 3 H]acetylcholine release were correlated with their potencies to stimulate adenylate cyclase (r = 0.784, P less than .05, n = 7) and with their affinities at [ 3 H]SCH 23390 binding sites (r = 0.755, P < .05, n = 8)

Protection by imidazol(ine) drugs and agmatine of glutamate-induced neurotoxicity in cultured cerebellar granule cells through blockade of NMDA receptor.

Science.gov (United States)

Olmos, G; DeGregorio-Rocasolano, N; Paz Regalado, M; Gasull, T; Assumpció Boronat, M; Trullas, R; Villarroel, A; Lerma, J; García-Sevilla, J A

1999-07-01

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 microM) caused a concentration-dependent neurotoxicity, as determined 24 h later by a decrease in the ability of the cells to metabolize 3-(4,5-dimethythiazol-2-yl)-2,5-diphenyltetrazoliumbromide (MTT) into a reduced formazan product. L-glutamate-induced neurotoxicity (EC50=5 microM) was blocked by the specific NMDA receptor antagonist MK-801 (dizocilpine). Imidazol(ine) drugs and agmatine fully prevented neurotoxicity induced by 20 microM (EC100) L-glutamate with the rank order (EC50 in microM): 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)>RX82 1002 (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 microM at 0 mV. It is concluded that imidazol(ine) drugs and agmatine are

In vitro binding and receptor-mediated activity of terlipressin at vasopressin receptors V1 and V2.

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Jamil, Khurram; Pappas, Stephen Chris; Devarakonda, Krishna R

2018-01-01

Terlipressin, a synthetic, systemic vasoconstrictor with selective activity at vasopressin-1 (V 1 ) receptors, is a pro-drug for the endogenous/natural porcine hormone [Lys 8 ]-vasopressin (LVP). We investigated binding and receptor-mediated cellular activities of terlipressin, LVP, and endogenous human hormone [Arg 8 ]-vasopressin (AVP) at V 1 and vasopressin-2 (V 2 ) receptors. Cell membrane homogenates of Chinese hamster ovary cells expressing human V 1 and V 2 receptors were used in competitive binding assays to measure receptor-binding activity. These cells were used in functional assays to measure receptor-mediated cellular activity of terlipressin, LVP, and AVP. Binding was measured by [ 3 H]AVP counts, and the activity was measured by fluorometric detection of intracellular calcium mobilization (V 1 ) and cyclic adenosine monophosphate (V 2 ). Binding potency at V 1 and V 2 was AVP>LVP>terlipressin. LVP and terlipressin had approximately sixfold higher affinity for V 1 than for V 2 . Cellular activity potency was also AVP>LVP>terlipressin. Terlipressin was a partial agonist at V 1 and a full agonist at V 2 ; LVP was a full agonist at both V 1 and V 2 . The in vivo response to terlipressin is likely due to the partial V 1 agonist activity of terlipressin and full V 1 agonist activity of its metabolite, LVP. These results provide supportive evidence for previous findings and further establish terlipressin pharmacology for vasopressin receptors.

Cellular and behavioural profile of the novel, selective neurokinin1 receptor antagonist, vestipitant: a comparison to other agents.

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Brocco, Mauricette; Dekeyne, Anne; Mannoury la Cour, Clotilde; Touzard, Manuelle; Girardon, Sylvie; Veiga, Sylvie; de Nanteuil, Guillaume; deJong, Trynke R; Olivier, Berend; Millan, Mark J

2008-10-01

This study characterized the novel neurokinin (NK)(1) antagonist, vestipitant, under clinical evaluation for treatment of anxiety and depression. Vestipitant possessed high affinity for human NK(1) receptors (pK(i), 9.4), and potently blocked Substance P-mediated phosphorylation of Extracellular-Regulated-Kinase. In vivo, it occupied central NK(1) receptors in gerbils (Inhibitory Dose(50), 0.11 mg/kg). At similar doses, it abrogated nociception elicited by formalin in gerbils, and blocked foot-tapping and locomotion elicited by the NK(1) agonist, GR73632, in gerbils and guinea pigs, respectively. Further, vestipitant attenuated fear-induced foot-tapping in gerbils, separation-induced distress-vocalizations in guinea pigs, marble-burying behaviour in mice, and displayed anxiolytic actions in Vogel conflict and fear-induced ultrasonic vocalization procedures in rats. These actions were mimicked by CP99,994, L733,060 and GR205,171 which acted stereoselectively vs its less active isomer, GR226,206. In conclusion, vestipitant is a potent NK(1) receptor antagonist: its actions support the utility of NK(1) receptor blockade in the alleviation of anxiety and, possibly, depression.

D1 receptors regulate dendritic morphology in normal and stressed prelimbic cortex.

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Lin, Grant L; Borders, Candace B; Lundewall, Leslie J; Wellman, Cara L

2015-01-01

Both stress and dysfunction of prefrontal cortex are linked to psychological disorders, and structure and function of medial prefrontal cortex (mPFC) are altered by stress. Chronic restraint stress causes dendritic retraction in the prelimbic region (PL) of mPFC in rats. Dopamine release in mPFC increases during stress, and chronic administration of dopaminergic agonists results in dendritic remodeling. Thus, stress-induced alterations in dopaminergic transmission in PL may contribute to dendritic remodeling. We examined the effects of dopamine D1 receptor (D1R) blockade in PL during daily restraint stress on dendritic morphology in PL. Rats either underwent daily restraint stress (3h/day, 10 days) or remained unstressed. In each group, rats received daily infusions of either the D1R antagonist SCH23390 or vehicle into PL prior to restraint; unstressed and stressed rats that had not undergone surgery were also examined. On the final day of restraint, rats were euthanized and brains were processed for Golgi histology. Pyramidal neurons in PL were reconstructed and dendritic morphology was quantified. Vehicle-infused stressed rats demonstrated dendritic retraction compared to unstressed rats, and D1R blockade in PL prevented this effect. Moreover, in unstressed rats, D1R blockade produced dendritic retraction. These effects were not due to attenuation of the HPA axis response to acute stress: plasma corticosterone levels in a separate group of rats that underwent acute restraint stress with or without D1R blockade were not significantly different. These findings indicate that dopaminergic transmission in mPFC during stress contributes directly to the stress-induced retraction of apical dendrites, while dopamine transmission in the absence of stress is important in maintaining normal dendritic morphology. Copyright © 2014 Elsevier Ltd. All rights reserved.

Circadian rhythm disruption by a novel running wheel: Roles of exercise and arousal in blockade of the luteinizing hormone surge

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Duncan, Marilyn J.; Franklin, Kathleen M.; Peng, Xiaoli; Yun, Christopher; Legan, Sandra J.

2014-01-01

Exposure of proestrous Syrian hamsters to a new room, cage, and novel running wheel blocks the luteinizing hormone (LH) surge until the next day in ~75% of hamsters (Legan et al, 2010) [1]. The studies described here tested the hypotheses that 1) exercise and/or 2) orexinergic neurotransmission mediate novel wheel blockade of the LH surge and circadian phase advances. Female hamsters were exposed to a 14L:10D photoperiod and activity rhythms were monitored with infra-red detectors. In Expt. 1, to test the effect of exercise, hamsters received jugular cannulae and on the next day, proestrus (Day 1), shortly before zeitgeber time 5 (ZT 5, 7 hours before lights-off) the hamsters were transported to the laboratory. After obtaining a blood sample at ZT 5, the hamsters were transferred to a new cage with a novel wheel that was either freely rotating (unlocked), or locked until ZT 9, and exposed to constant darkness (DD). Blood samples were collected hourly for 2 days from ZT 5–11 under red light for determination of plasma LH levels by radioimmunoassay. Running rhythms were monitored continuously for the next 10–14 days. The locked wheels were as effective as unlocked wheels in blocking LH surges (no Day 1 LH surge in 6/9 versus 8/8 hamsters, P>0.05) and phase advances in the activity rhythms did not differ between the groups (P= 0.28), suggesting that intense exercise is not essential for novel wheel blockade and phase advance of the proestrous LH surge. Expt. 2 tested whether orexin neurotransmission is essential for these effects. Hamsters were treated the same as in Expt. 1 except they were injected (i.p.) at ZT 4.5 and 5 with either the orexin 1 receptor antagonist SB334867 (15 mg/kg per injection) or vehicle (25% DMSO in 2-hydroxypropyl-beta-cyclodextrin (HCD). SB-334867 inhibited novel wheel blockade of the LH surge (surges blocked in 2/6 SB334867-injected animals versus 16/18 vehicle-injected animals, Pwheel running and circadian phase shifts, indicating that

Inhibition of Protease-activated Receptor 1 Ameliorates Intestinal Radiation Mucositis in a Preclinical Rat Model

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Wang, Junru; Kulkarni, Ashwini [Division of Radiation Health, University of Arkansas for Medical Sciences, Little Rock, Arkansas (United States); Chintala, Madhu [Schering-Plough Research Institute, Kenilworth, New Jersey (United States); Fink, Louis M. [Nevada Cancer Institute, Las Vegas, Nevada (United States); Hauer-Jensen, Martin, E-mail: mhjensen@life.uams.edu [Division of Radiation Health, University of Arkansas for Medical Sciences, Little Rock, Arkansas (United States); Surgery Service, Central Arkansas Veterans Healthcare System, Little Rock, Arkansas (United States)

2013-01-01

Purpose: To determine, using a specific small-molecule inhibitor of protease-activated receptor 1 (PAR1) signaling, whether the beneficial effect of thrombin inhibition on radiation enteropathy development is due to inhibition of blood clotting or to cellular (PAR1-mediated) thrombin effects. Methods and Materials: Rats underwent fractionated X-irradiation (5 Gy Multiplication-Sign 9) of a 4-cm small-bowel segment. Early radiation toxicity was evaluated in rats receiving PAR1 inhibitor (SCH602539, 0, 10, or 15 mg/kg/d) from 1 day before to 2 weeks after the end of irradiation. The effect of PAR1 inhibition on development of chronic intestinal radiation fibrosis was evaluated in animals receiving SCH602539 (0, 15, or 30 mg/kg/d) until 2 weeks after irradiation, or continuously until termination of the experiment 26 weeks after irradiation. Results: Blockade of PAR1 ameliorated early intestinal toxicity, with reduced overall intestinal radiation injury (P=.002), number of myeloperoxidase-positive (P=.03) and proliferating cell nuclear antigen-positive (P=.04) cells, and collagen III accumulation (P=.005). In contrast, there was no difference in delayed radiation enteropathy in either the 2- or 26-week administration groups. Conclusion: Pharmacological blockade of PAR1 seems to reduce early radiation mucositis but does not affect the level of delayed intestinal radiation fibrosis. Early radiation enteropathy is related to activation of cellular thrombin receptors, whereas platelet activation or fibrin formation may play a greater role in the development of delayed toxicity. Because of the favorable side-effect profile, PAR1 blockade should be further explored as a method to ameliorate acute intestinal radiation toxicity in patients undergoing radiotherapy for cancer and to protect first responders and rescue personnel in radiologic/nuclear emergencies.

Cannabinoid Receptors CB1 and CB2 Modulate the Electroretinographic Waves in Vervet Monkeys

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Joseph Bouskila

2016-01-01

Full Text Available The expression patterns of the cannabinoid receptor type 1 (CB1R and the cannabinoid receptor type 2 (CB2R are well documented in rodents and primates. In vervet monkeys, CB1R is present in the retinal neurons (photoreceptors, horizontal cells, bipolar cells, amacrine cells, and ganglion cells and CB2R is exclusively found in the retinal glia (Müller cells. However, the role of these cannabinoid receptors in normal primate retinal function remains elusive. Using full-field electroretinography in adult vervet monkeys, we recorded changes in neural activity following the blockade of CB1R and CB2R by the intravitreal administration of their antagonists (AM251 and AM630, resp. in photopic and scotopic conditions. Our results show that AM251 increases the photopic a-wave amplitude at high flash intensities, whereas AM630 increases the amplitude of both the photopic a- and b-waves. In scotopic conditions, both blockers increased the b-wave amplitude but did not change the a-wave amplitude. These findings suggest an important role of CB1R and CB2R in primate retinal function.

C5a receptor (CD88) blockade protects against MPO-ANCA GN.

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Xiao, Hong; Dairaghi, Daniel J; Powers, Jay P; Ertl, Linda S; Baumgart, Trageen; Wang, Yu; Seitz, Lisa C; Penfold, Mark E T; Gan, Lin; Hu, Peiqi; Lu, Bao; Gerard, Norma P; Gerard, Craig; Schall, Thomas J; Jaen, Juan C; Falk, Ronald J; Jennette, J Charles

2014-02-01

Necrotizing and crescentic GN (NCGN) with a paucity of glomerular immunoglobulin deposits is associated with ANCA. The most common ANCA target antigens are myeloperoxidase (MPO) and proteinase 3. In a manner that requires activation of the alternative complement pathway, passive transfer of antibodies to mouse MPO (anti-MPO) induces a mouse model of ANCA NCGN that closely mimics human disease. Here, we confirm the importance of C5aR/CD88 in the mediation of anti-MPO-induced NCGN and report that C6 is not required. We further demonstrate that deficiency of C5a-like receptor (C5L2) has the reverse effect of C5aR/CD88 deficiency and results in more severe disease, indicating that C5aR/CD88 engagement enhances inflammation and C5L2 engagement suppresses inflammation. Oral administration of CCX168, a small molecule antagonist of human C5aR/CD88, ameliorated anti-MPO-induced NCGN in mice expressing human C5aR/CD88. These observations suggest that blockade of C5aR/CD88 might have therapeutic benefit in patients with ANCA-associated vasculitis and GN.

Integrative function of adrenaline receptors for glucagon-like peptide-1 exocytosis in enteroendocrine L cell line GLUTag.

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Harada, Kazuki; Kitaguchi, Tetsuya; Tsuboi, Takashi

2015-05-15

Adrenaline reacts with three types of adrenergic receptors, α1, α2 and β-adrenergic receptors (ARs), inducing many physiological events including exocytosis. Although adrenaline has been shown to induce glucagon-like peptide-1 (GLP-1) secretion from intestinal L cells, the precise molecular mechanism by which adrenaline regulates GLP-1 secretion remains unknown. Here we show by live cell imaging that all types of adrenergic receptors are stimulated by adrenaline in enteroendocrine L cell line GLUTag cells and are involved in GLP-1 exocytosis. We performed RT-PCR analysis and found that α1B-, α2A-, α2B-, and β1-ARs were expressed in GLUTag cells. Application of adrenaline induced a significant increase of intracellular Ca(2+) and cAMP concentration ([Ca(2+)]i and [cAMP]i, respectively), and GLP-1 exocytosis in GLUTag cells. Blockade of α1-AR inhibited adrenaline-induced [Ca(2+)]i increase and exocytosis but not [cAMP]i increase, while blockade of β1-AR inhibited adrenaline-induced [cAMP]i increase and exocytosis but not [Ca(2+)]i increase. Furthermore, overexpression of α2A-AR suppressed the adrenaline-induced [cAMP]i increase and exocytosis. These results suggest that the fine-turning of GLP-1 secretion from enteroendocrine L cells is established by the balance between α1-, α2-, and β-ARs activation. Copyright © 2015 Elsevier Inc. All rights reserved.

Hypertensive response to stress: the role of histaminergic H1 and H2 receptors in the medial amygdala.

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de Almeida, Daniela Oliveira; Ferreira, Hilda Silva; Pereira, Luana Bomfim; Fregoneze, Josmara Bartolomei

2015-05-15

Different brain areas seem to be involved in the cardiovascular responses to stress. The medial amygdala (MeA) has been shown to participate in cardiovascular control, and acute stress activates the MeA to a greater extent than any of the other amygdaloid structures. It has been demonstrated that the brain histaminergic system may be involved in behavioral, autonomic and neuroendocrine responses to stressful situations. The aim of the present study was to investigate the role of the histaminergic receptors H1 and H2 in cardiovascular responses to acute restraint stress. Wistar rats (280-320g) received bilateral injections of cimetidine, mepyramine or saline into the MeA and were submitted to 45min of restraint stress. Mepyramine microinjections at doses of 200, 100 and 50nmol promoted a dose-dependent blockade of the hypertensive response induced by the restraint stress. Cimetidine (200 and 100nmol) promoted a partial blockade of the hypertensive response to stress only at the highest dose administered. Neither drugs altered the typical stress-evoked tachycardiac responses. Furthermore, mepyramine and cimetidine were unable to modify the mean arterial pressure or heart rate of freely moving rats under basal conditions (non-stressed rats). The data suggest that in the MeA the histaminergic H1 receptors appear to be more important than H2 receptors in the hypertensive response to stress. Furthermore, there appears to be no histaminergic tonus in the MeA controlling blood pressure during non-stress conditions. Copyright © 2015 Elsevier Inc. All rights reserved.

Enhancement of PSMA-Directed CAR Adoptive Immunotherapy by PD-1/PD-L1 Blockade

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Inna Serganova

2017-03-01

Full Text Available Chimeric antigen receptor (CAR T cell therapy in hematologic malignancies has shown remarkable responses, but the same level of success has not been observed in solid tumors. A new prostate cancer model (Myc-CaP:PSMA(+ and a second-generation anti-hPSMA human CAR T cells expressing a Click Beetle Red luciferase reporter were used to study hPSMA targeting and assess CAR T cell trafficking and persistence by bioluminescence imaging (BLI. We investigated the antitumor efficacy of human CAR T cells targeting human prostate-specific membrane antigen (hPSMA, in the presence and absence of the target antigen; first alone and then combined with a monoclonal antibody targeting the human programmed death receptor 1 (anti-hPD1 mAb. PDL-1 expression was detected in Myc-CaP murine prostate tumors growing in immune competent FVB/N and immune-deficient SCID mice. Endogenous CD3+ T cells were restricted from the centers of Myc-CaP tumor nodules growing in FVB/N mice. Following anti-programmed cell death protein 1 (PD-1 treatment, the restriction of CD3+ T cells was reversed, and a tumor-treatment response was observed. Adoptive hPSMA-CAR T cell immunotherapy was enhanced when combined with PD-1 blockade, but the treatment response was of comparatively short duration, suggesting other immune modulation mechanisms exist and restrict CAR T cell targeting, function, and persistence in hPSMA expressing Myc-CaP tumors. Interestingly, an “inverse pattern” of CAR T cell BLI intensity was observed in control and test tumors, which suggests CAR T cells undergo changes leading to a loss of signal and/or number following hPSMA-specific activation. The lower BLI signal intensity in the hPSMA test tumors (compared with controls is due in part to a decrease in T cell mitochondrial function following T cell activation, which may limit the intensity of the ATP-dependent Luciferin-luciferase bioluminescence signal.

Typical and Atypical Antipsychotic Drugs Increase Extracellular Histamine Levels in the Rat Medial Prefrontal Cortex: Contribution of Histamine H1 Receptor Blockade

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Kjell A Svensson

2012-05-01

Full Text Available Atypical antipsychotics such as clozapine and olanzapine have been shown to enhance histamine turnover and this effect has been hypothesized to contribute to their improved therapeutic profile compared to typical antipsychotics. In the present study, we examined the effects of antipsychotic drugs on histamine (HA efflux in the mPFC of the rat by means of in vivo microdialysis and sought to differentiate the receptor mechanisms which underlie such effects. Olanzapine and clozapine increased mPFC HA efflux in a dose related manner. Increased HA efflux was also observed after quetiapine, chlorpromazine and perphenazine treatment. We found no effect of the selective 5-HT2A antagonist MDL100907, 5-HT2c antagonist SB242084 or the 5-HT6 antagonist Ro 04-6790 on mPFC HA efflux. HA efflux was increased following treatment with selective H1 receptor antagonists pyrilamine, diphenhydramine and triprolidine, the H3 receptor antagonist ciproxifan and the mixed 5HT2A/H1 receptor antagonist ketanserin. The potential novel antipsychotic drug FMPD, which has a lower affinity at H1 receptors than olanzapine, did not affect HA efflux. Similarly, other antipsychotics with lower H1 receptor affinity (risperidone, aripiprazole and haloperidol were also without effect on HA efflux. Perfusion of clozapine and pyrilamine into the TMN, but not the mPFC, increased local HA efflux. Finally, HA efflux after antipsychotic treatment was significantly correlated with affinity at H1 receptors whereas 9 other receptors, including 5-HT2A, were not. These results demonstrate that both typical and atypical antipsychotics increase mPFC histamine efflux and this effect may be mediated via antagonism of histamine H1 receptors.

Selective blockade of TRPA1 channel attenuates pathological pain without altering noxious cold sensation or body temperature regulation.

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Chen, Jun; Joshi, Shailen K; DiDomenico, Stanley; Perner, Richard J; Mikusa, Joe P; Gauvin, Donna M; Segreti, Jason A; Han, Ping; Zhang, Xu-Feng; Niforatos, Wende; Bianchi, Bruce R; Baker, Scott J; Zhong, Chengmin; Simler, Gricelda H; McDonald, Heath A; Schmidt, Robert G; McGaraughty, Steve P; Chu, Katharine L; Faltynek, Connie R; Kort, Michael E; Reilly, Regina M; Kym, Philip R

2011-05-01

Despite the increasing interest in TRPA1 channel as a pain target, its role in cold sensation and body temperature regulation is not clear; the efficacy and particularly side effects resulting from channel blockade remain poorly understood. Here we use a potent, selective, and bioavailable antagonist to address these issues. A-967079 potently blocks human (IC(50): 51 nmol/L, electrophysiology, 67 nmol/L, Ca(2+) assay) and rat TRPA1 (IC(50): 101 nmol/L, electrophysiology, 289 nmol/L, Ca(2+) assay). It is >1000-fold selective over other TRP channels, and is >150-fold selective over 75 other ion channels, enzymes, and G-protein-coupled receptors. Oral dosing of A-967079 produces robust drug exposure in rodents, and exhibits analgesic efficacy in allyl isothiocyanate-induced nocifensive response and osteoarthritic pain in rats (ED(50): 23.2 mg/kg, p.o.). A-967079 attenuates cold allodynia produced by nerve injury but does not alter noxious cold sensation in naive animals, suggesting distinct roles of TRPA1 in physiological and pathological states. Unlike TRPV1 antagonists, A-967079 does not alter body temperature. It also does not produce locomotor or cardiovascular side effects. Collectively, these data provide novel insights into TRPA1 function and suggest that the selective TRPA1 blockade may present a viable strategy for alleviating pain without untoward side effects. Copyright © 2011 International Association for the Study of Pain. Published by Elsevier B.V. All rights reserved.

Tandospirone, a 5-HT1A partial agonist, ameliorates aberrant lactate production in the prefrontal cortex of rats exposed to blockade of N-methy-D-aspartate receptors; Towards the therapeutics of cognitive impairment of schizophrenia

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Takashi eUehara

2014-09-01

Full Text Available Rationale Augmentation therapy with serotonin-1A (5-HT1A receptor partial agonists has been suggested to improve cognitive deficits in patients with schizophrenia. Decreased activity of prefrontal cortex may provide a basis for cognitive deficits of the disease. Lactate plays a significant role in the supply of energy to the brain, and glutamatergic neurotransmission contributes to lactate production.Objectives and methods The purposes of this study were to examine the effect of repeated administration (once a daily for 4 days of tandospirone (0.05 and 5 mg/kg on brain energy metabolism, as represented by extracellular lactate concentration (eLAC in the medial prefrontal cortex (mPFC of young adult rats..Results Four-day treatment with MK-801, an NMDA-R antagonist, prolonged eLAC elevation induced by foot shock stress (FS. Co-administration with the high-dose tandospirone suppressed prolonged FS-induced eLAC elevation in rats receiving MK-801, whereas tandospirone by itself did not affected eLAC increment.Conclusions These results suggest that stimulation of 5-HT1A receptors ameliorates abnormalities of energy metabolism in the mPFC due to blockade of NMDA receptors. These findings provide a possible mechanism based on brain energy metabolism by which 5-HT1A agonism improve cognitive impairment in schizophrenia and related disorders.

The Roles of Dopamine D1 Receptor on the Social Hierarchy of Rodents and Nonhuman Primates.

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Yamaguchi, Yoshie; Lee, Young-A; Kato, Akemi; Goto, Yukiori

2017-04-01

Although dopamine has been suggested to play a role in mediating social behaviors of individual animals, it is not clear whether such dopamine signaling contributes to attributes of social groups such as social hierarchy. In this study, the effects of the pharmacological manipulation of dopamine D1 receptor function on the social hierarchy and behavior of group-housed mice and macaques were investigated using a battery of behavioral tests. D1 receptor blockade facilitated social dominance in mice at the middle, but not high or low, social rank in the groups without altering social preference among mates. In contrast, the administration of a D1 receptor antagonist in a macaque did not affect social dominance of the drug-treated animal; however, relative social dominance relationships between the drug-treated and nontreated subjects were altered indirectly through alterations of social affiliative relationships within the social group. These results suggest that dopamine D1 receptor signaling may be involved in social hierarchy and social relationships within a group, which may differ between rodents and primates. © The Author 2016. Published by Oxford University Press on behalf of CINP.

T156. IN VIVO CHARACTERIZATION OF THE FIRST AGONIST DOPAMINE D1 RECEPTORS PET IMAGING TRACER [18F]MNI-968 IN HUMAN

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Tamagnan, Gilles; Barret, Olivier; Alagille, David; Carroll, Vincent; Madonia, Jennifer; Constantinescu, Cristian; SanDiego, Christine; Papin, Caroline; Morley, Thomas; Russell, David; McCarthy, Timothy; Zhang, Lei; Gray, David; Villalobos, Anna; Lee, Chewah; Chen, Jianqing; Seibyl, John; Marek, Kenneth

2018-01-01

Abstract Background D1 receptors, which couple to inhibitory G-proteins, have been shown to regulate neuronal growth and development, mediate some behavioral responses. Its function has been shown to be altered in both neurologic and psychiatric disorders. To date, there is a lack of agonist PET tracers for the D1 receptors labeled with 18F with relevance in clinical studies. We report the evaluation in non-human primates of [18F]MNI-968 (PF-06730110), a novel PET radiotracer of the D1 receptors Methods Four brain PET studies, 2 baselines and 2 blockade studies using PF-2562, a D1 partial agonist compound, were conducted for 90 min in two rhesus monkeys with [18F]MNI-968 (169 ± 31 MBq). [18F]PF-06730110 was administered at the same dose level for both monkeys as a bolus followed by a 2-hour infusion, with [18F]MNI-968 administered 30 min into the infusion. Additionally, six brain PET studies were conducted over 180 min (317 ± 49 MBq) in 6 healthy human volunteers (3 test/retest and 3 test). PET data were modeled with 2-tissue compartmental model (2T), Logan graphical analysis (LGA), and non-invasive Logan graphical analysis (NI-LGA) with cerebellar cortex as reference region to estimate total distribution volume VT, and binding potential BPND. For the blockade studies in rhesus monkeys, occupancy was estimated from BPND at baseline and post blockade. Results In rhesus monkeys, [18F]MNI-968 (PF-06730110), penetrated the brain with a peak whole-brain uptake up to ~3% of the injected dose at ~ 6 min post injection and showed a fast washout. The highest signal was found in the caudate, putamen, with moderate extrastriatal uptake. The lowest signal was in the cerebellum. BPND values were up to ~1.4 in the putamen. All three quantification methods (2T, LGA and NI-LGA) were in excellent agreement, with a similar estimated D1 receptors occupancy of PF-06730110 of ~40% for both monkeys in the caudate and putamen. In human, [18F]MNI-968 kinetics appeared to be faster

Small Molecule Drug Discovery at the Glucagon-Like Peptide-1 Receptor

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Francis S. Willard

2012-01-01

Full Text Available The therapeutic success of peptide glucagon-like peptide-1 (GLP-1 receptor agonists for the treatment of type 2 diabetes mellitus has inspired discovery efforts aimed at developing orally available small molecule GLP-1 receptor agonists. Although the GLP-1 receptor is a member of the structurally complex class B1 family of GPCRs, in recent years, a diverse array of orthosteric and allosteric nonpeptide ligands has been reported. These compounds include antagonists, agonists, and positive allosteric modulators with intrinsic efficacy. In this paper, a comprehensive review of currently disclosed small molecule GLP-1 receptor ligands is presented. In addition, examples of “ligand bias” and “probe dependency” for the GLP-1 receptor are discussed; these emerging concepts may influence further optimization of known molecules or persuade designs of expanded screening strategies to identify novel chemical starting points for GLP-1 receptor drug discovery.

Pre-diabetes augments neuropeptide Y1- and α1-receptor control of basal hindlimb vascular tone in young ZDF rats.

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Nicole M Novielli

Full Text Available Peripheral vascular disease in pre-diabetes may involve altered sympathetically-mediated vascular control. Thus, we investigated if pre-diabetes modifies baseline sympathetic Y(1-receptor (Y(1R and α(1-receptor (α(1R control of hindlimb blood flow (Q(fem and vascular conductance (VC.Q(fem and VC were measured in pre-diabetic ZDF rats (PD and lean controls (CTRL under infusion of BIBP3226 (Y(1R antagonist, prazosin (α(1R antagonist and BIBP3226+prazosin. Neuropeptide Y (NPY concentration and Y(1R and α(1R expression were determined from hindlimb skeletal muscle samples.Baseline Q(fem and VC were similar between groups. Independent infusions of BIBP3226 and prazosin led to increases in Q(fem and VC in CTRL and PD, where responses were greater in PD (p<0.05. The percent change in VC following both drugs was also greater in PD compared to CTRL (p<0.05. As well, Q(fem and VC responses to combined blockade (BIBP3226+prazosin were greater in PD compared to CTRL (p<0.05. Interestingly, an absence of synergistic effects was observed within groups, as the sum of the VC responses to independent drug infusions was similar to responses following combined blockade. Finally, white and red vastus skeletal muscle NPY concentration, Y(1R expression and α(1R expression were greater in PD compared to CTRL.For the first time, we report heightened baseline Y(1R and α(1R sympathetic control of Q(fem and VC in pre-diabetic ZDF rats. In support, our data suggest that augmented sympathetic ligand and receptor expression in pre-diabetes may contribute to vascular dysregulation.

Differential effects of B7-1 blockade in the rat experimental autoimmune encephalomyelitis model

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Gallon, L; Chandraker, A; Issazadeh-Navikas, Shohreh

1997-01-01

that CD28-B7 blockade by systemic administration of CTLA4Ig prevents actively induced EAE. Since CTLA4Ig binds to both B7-1 and B7-2, we used a mutant form of CTLA4Ig (CTLA4IgY100F) that binds only B7-1, to study the role of B7-1 blockade in this model. Such a reagent avoids the potential of signaling...... treated with systemic CTLA4gY100F did not. More importantly, systemic administration of CTLA4IgY100F abrogated the protective effect of ex vivo treated APCs. These data suggest an important regulatory role for B7-1, perhaps through binding to CTLA4, in this model of EAE. Understanding the role......Blocking the CD28-B7 T cell costimulatory activation pathway protects animals from developing experimental autoimmune encephalomyelitis (EAE). In the mouse EAE model, selective blockade of B7-1 by specific mAbs has been shown to protect animals from EAE. In the Lewis rat model, we have shown...

Pharmacological significance of the interplay between angiotensin receptors: MAS receptors as putative final mediators of the effects elicited by angiotensin AT1 receptors antagonists.

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Pernomian, Larissa; Pernomian, Laena; Gomes, Mayara S; da Silva, Carlos H T P

2015-12-15

The interplay between angiotensin AT1 receptors and MAS receptors relies on several inward regulatory mechanisms from renin-angiotensin system (RAS) including the functional crosstalk between angiotensin II and angiotensin-(1-7), the competitive AT1 antagonism exhibited by angiotensin-(1-7), the antagonist feature assigned to AT1/MAS heterodimerization on AT1 signaling and the AT1-mediated downregulation of angiotensin-converting enzyme 2 (ACE2). Recently, such interplay has acquired an important significance to RAS Pharmacology since a few studies have supporting strong evidences that MAS receptors mediate the effects elicited by AT1 antagonists. The present Perspective provides an overview of the regulatory mechanisms involving AT1 and MAS receptors, their significance to RAS Pharmacology and the future directions on the interplay between angiotensin receptors. Copyright © 2015 Elsevier B.V. All rights reserved.

Pharmacological or genetic orexin 1 receptor inhibition attenuates MK-801 induced glutamate release in mouse cortex

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Leah eAluisio

2014-05-01

Full Text Available The orexin/hypocretin neuropeptides are produced by a cluster of neurons within the lateral posterior hypothalamus and participate in neuronal regulation by activating their receptors (OX1 and OX2 receptors. The orexin system projects widely through the brain and functions as an interface between multiple regulatory systems including wakefulness, energy balance, stress, reward and emotion. Recent studies have demonstrated that orexins and glutamate interact at the synaptic level and that orexins facilitate glutamate actions. We tested the hypothesis that orexins modulate glutamate signaling via OX1 receptors by monitoring levels of glutamate in frontal cortex of freely moving mice using enzyme coated biosensors under inhibited OX1 receptor conditions. MK-801, an NMDA receptor antagonist, was administered subcutaneously (0.178 mg/kg to indirectly disinhibit pyramidal neurons and therefore increase cortical glutamate release. In wild-type mice, pretreatment with the OX1 receptor antagonist GSK-1059865 (10 mg/kg S.C. which had no effect by itself, significantly attenuated the cortical glutamate release elicited by MK-801. OX1 receptor knockout mice had a blunted glutamate release response to MK-801 and exhibited about half of the glutamate release observed in wild-type mice in agreement with the data obtained with transient blockade of OX1 receptors. These results indicate that pharmacological (transient or genetic (permanent inhibition of the OX1 receptor similarly interfere with glutamatergic function in the cortex. Selectively targeting the OX1 receptor with an antagonist may normalize hyperglutamatergic states and thus may represent a novel therapeutic strategy for the treatment of various psychiatric disorders associated with hyperactive states.

Increase of cells expressing PD-L1 in bovine leukemia virus infection and enhancement of anti-viral immune responses in vitro via PD-L1 blockade

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Ikebuchi Ryoyo

2011-09-01

Full Text Available Abstract The inhibitory receptor programmed death-1 (PD-1 and its ligand, programmed death-ligand 1 (PD-L1 are involved in immune evasion mechanisms for several pathogens causing chronic infections. Blockade of the PD-1/PD-L1 pathway restores anti-virus immune responses, with concomitant reduction in viral load. In a previous report, we showed that, in bovine leukemia virus (BLV infection, the expression of bovine PD-1 is closely associated with disease progression. However, the functions of bovine PD-L1 are still unknown. To investigate the role of PD-L1 in BLV infection, we identified the bovine PD-L1 gene, and examined PD-L1 expression in BLV-infected cattle in comparison with uninfected cattle. The deduced amino acid sequence of bovine PD-L1 shows high homology to the human and mouse PD-L1. The proportion of PD-L1 positive cells, especially among B cells, was upregulated in cattle with the late stage of the disease compared to cattle at the aleukemic infection stage or uninfected cattle. The proportion of PD-L1 positive cells correlated positively with prediction markers for the progression of the disease such as leukocyte number, virus load and virus titer whilst on the contrary, it inversely correlated with the degree of interferon-gamma expression. Blockade of the PD-1/PD-L1 pathway in vitro by PD-L1-specific antibody upregulated the production of interleukin-2 and interferon-gamma, and correspondingly, downregulated the BLV provirus load and the proportion of BLV-gp51 expressing cells. These data suggest that PD-L1 induces immunoinhibition in disease progressed cattle during chronic BLV infection. Therefore, PD-L1 would be a potential target for developing immunotherapies against BLV infection.

Polymorphisms in the endocannabinoid receptor 1 in relation to fat mass distribution

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Nielsen, Morten Frost; Nielsen, T L; Wraae, K

2010-01-01

OBJECTIVE: Both animal and human studies have associated the endocannabinoid system with obesity and markers of metabolic dysfunction. Blockade of the cannabinoid receptor 1 (CB1) caused weight loss and reduction in waist size in both obese and type II diabetics. Recent studies on common variants...... of the CB1 receptor gene (CNR1) and the link to obesity have been conflicting. The aim of the present study was to evaluate whether selected common variants of the CNR1 are associated with measures of obesity and fat distribution. DESIGN AND METHODS: The single nucleotide polymorphisms (SNPs) rs806381, rs......10485179 and rs1049353 were genotyped, and body fat and fat distribution were assessed by the use of dual-energy X-ray absorptiometry and magnetic resonance imaging in a population-based study comprising of 783 Danish men, aged 20-29 years. RESULTS: The rs806381 polymorphism was significantly associated...

Evidence of changes in alpha-1/AT1 receptor function generated by diet-induced obesity.

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Juarez, Esther; Tufiño, Cecilia; Querejeta, Enrique; Bracho-Valdes, Ismael; Bobadilla-Lugo, Rosa A

2017-11-01

To study whether hypercaloric diet-induced obesity deteriorates vascular contractility of rat aorta through functional changes in α 1 adrenergic and/or AT1 Angiotensin II receptors. Angiotensin II- or phenylephrine-induced contraction was tested on isolated aorta rings with and without endothelium from female Wistar rats fed for 7 weeks with hypercaloric diet or standard diet. Vascular expression of Angiotensin II Receptor type 1 (AT1R), Angiotensin II Receptor type 2 (AT2R), Cyclooxygenase-1 (COX-1), Cyclooxygenase-2 (COX-2), inducible Nitric Oxide Synthase (iNOS) and endothelial Nitric Oxide Synthase (eNOS), as well as blood pressure, glucose, insulin and angiotensin II blood levels were measured. Diet-induced obesity did not significantly change agonist-induced contractions (Emax and pD 2 hypercaloric diet vs standard diet n.s.d.) of both intact (e+) or endothelium free (e-) vessels but significantly decrease both phenylephrine and angiotensin II contraction (Emax p obesity did not change angiotensin II AT1, AT2 receptor proteins expression but reduced COX-1 and NOS2 ( p obesity produces alterations in vascular adrenergic and angiotensin II receptor dynamics that suggest an endothelium-dependent adrenergic/angiotensin II crosstalk. These changes reflect early-stage vascular responses to obesity.

Photon blockade in optomechanical systems with a position-modulated Kerr-type nonlinear coupling

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Zhang, X. Y.; Zhou, Y. H.; Guo, Y. Q.; Yi, X. X.

2018-03-01

We explore the photon blockade in optomechanical systems with a position-modulated Kerr-type nonlinear coupling, i.e. H_int˜\\hat{a}\\dagger2\\hat{a}^2(\\hat{b}_1^\\dagger+\\hat{b}_1) . We find that the Kerr-type nonlinear coupling can enhance the photon blockade greatly. We evaluate the equal-time second-order correlation function of the cavity photons and find that the optimal photon blockade does not happen at the single photon resonance. By working within the few-photon subspace, we get an approximate analytical expression for the correlation function and the condition for the optimal photon blockade. We also find that the photon blockade effect is not always enhanced as the Kerr-type nonlinear coupling strength g 2 increases. At some values of g 2, the photon blockade is even weakened. For the system we considered here, the second-order correlation function can be smaller than 1 even in the unresolved sideband regime. By numerically simulating the master equation of the system, we also find that the thermal noise of the mechanical environment can enhance the photon blockade. We give out an explanation for this counter-intuitive phenomenon qualitatively.

Biologic effects of platelet-derived growth factor receptor α blockade in uterine cancer.

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Roh, Ju-Won; Huang, Jie; Hu, Wei; Yang, XiaoYun; Jennings, Nicholas B; Sehgal, Vasudha; Sohn, Bo Hwa; Han, Hee Dong; Lee, Sun Joo; Thanapprapasr, Duangmani; Bottsford-Miller, Justin; Zand, Behrouz; Dalton, Heather J; Previs, Rebecca A; Davis, Ashley N; Matsuo, Koji; Lee, Ju-Seog; Ram, Prahlad; Coleman, Robert L; Sood, Anil K

2014-05-15

Platelet-derived growth factor receptor α (PDGFRα) expression is frequently observed in many kinds of cancer and is a candidate for therapeutic targeting. This preclinical study evaluated the biologic significance of PDGFRα and PDGFRα blockade (using a fully humanized monoclonal antibody, 3G3) in uterine cancer. Expression of PDGFRα was examined in uterine cancer clinical samples and cell lines, and biologic effects of PDGFRα inhibition were evaluated using in vitro (cell viability, apoptosis, and invasion) and in vivo (orthotopic) models of uterine cancer. PDGFRα was highly expressed and activated in uterine cancer samples and cell lines. Treatment with 3G3 resulted in substantial inhibition of PDGFRα phosphorylation and of downstream signaling molecules AKT and mitogen-activated protein kinase (MAPK). Cell viability and invasive potential of uterine cancer cells were also inhibited by 3G3 treatment. In orthotopic mouse models of uterine cancer, 3G3 monotherapy had significant antitumor effects in the PDGFRα-positive models (Hec-1A, Ishikawa, Spec-2) but not in the PDGFRα-negative model (OVCA432). Greater therapeutic effects were observed for 3G3 in combination with chemotherapy than for either drug alone in the PDGFRα-positive models. The antitumor effects of therapy were related to increased apoptosis and decreased proliferation and angiogenesis. These findings identify PDGFRα as an attractive target for therapeutic development in uterine cancer. ©2014 American Association for Cancer Research.

Blockade of TGF-β 1 Signalling Inhibits Cardiac NADPH Oxidase Overactivity in Hypertensive Rats

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José Luis Miguel-Carrasco

2012-01-01

Full Text Available NADPH oxidases constitute a major source of superoxide anion (⋅O2 - in hypertension. Several studies suggest an important role of NADPH oxidases in different effects mediated by TGF-β 1. In this study we show that chronic administration of P144, a peptide synthesized from type III TGF-β 1 receptor, significantly reduced the cardiac NADPH oxidase expression and activity as well as in the nitrotyrosine levels observed in control spontaneously hypertensive rats (V-SHR to levels similar to control normotensive Wistar Kyoto rats. In addition, P144 was also able to reduce the significant increases in the expression of collagen type I protein and mRNA observed in hearts from V-SHR. In addition, positive correlations between collagen expression, NADPH oxidase activity, and nitrotyrosine levels were found in all animals. Finally, TGF-β 1-stimulated Rat-2 exhibited significant increases in NADPH oxidase activity that was inhibited in the presence of P144. It could be concluded that the blockade of TGF-β 1 with P144 inhibited cardiac NADPH oxidase in SHR, thus adding new data to elucidate the involvement of this enzyme in the profibrotic actions of TGF-β 1.

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

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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.

Effects of sugammadex on incidence of postoperative residual neuromuscular blockade

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Brueckmann, B; Sasaki, N; Grobara, P

2015-01-01

BACKGROUND: This study aimed to investigate whether reversal of rocuronium-induced neuromuscular blockade with sugammadex reduced the incidence of residual blockade and facilitated operating room discharge readiness. METHODS: Adult patients undergoing abdominal surgery received rocuronium, followed...... by randomized allocation to sugammadex (2 or 4 mg kg(-1)) or usual care (neostigmine/glycopyrrolate, dosing per usual care practice) for reversal of neuromuscular blockade. Timing of reversal agent administration was based on the providers' clinical judgement. Primary endpoint was the presence of residual...... measured at PACU entry. Zero out of 74 sugammadex patients and 33 out of 76 (43.4%) usual care patients had TOF-Watch® SX-assessed residual neuromuscular blockade at PACU admission (odds ratio 0.0, 95% CI [0-0.06], P

Peripheral and central CB1 cannabinoid receptors control stress-induced impairment of memory consolidation.

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Busquets-Garcia, Arnau; Gomis-González, Maria; Srivastava, Raj Kamal; Cutando, Laura; Ortega-Alvaro, Antonio; Ruehle, Sabine; Remmers, Floortje; Bindila, Laura; Bellocchio, Luigi; Marsicano, Giovanni; Lutz, Beat; Maldonado, Rafael; Ozaita, Andrés

2016-08-30

Stressful events can generate emotional memories linked to the traumatic incident, but they also can impair the formation of nonemotional memories. Although the impact of stress on emotional memories is well studied, much less is known about the influence of the emotional state on the formation of nonemotional memories. We used the novel object-recognition task as a model of nonemotional memory in mice to investigate the underlying mechanism of the deleterious effect of stress on memory consolidation. Systemic, hippocampal, and peripheral blockade of cannabinoid type-1 (CB1) receptors abolished the stress-induced memory impairment. Genetic deletion and rescue of CB1 receptors in specific cell types revealed that the CB1 receptor population specifically in dopamine β-hydroxylase (DBH)-expressing cells is both necessary and sufficient for stress-induced impairment of memory consolidation, but CB1 receptors present in other neuronal populations are not involved. Strikingly, pharmacological manipulations in mice expressing CB1 receptors exclusively in DBH(+) cells revealed that both hippocampal and peripheral receptors mediate the impact of stress on memory consolidation. Thus, CB1 receptors on adrenergic and noradrenergic cells provide previously unrecognized cross-talk between central and peripheral mechanisms in the stress-dependent regulation of nonemotional memory consolidation, suggesting new potential avenues for the treatment of cognitive aspects on stress-related disorders.

Functional magnetic resonance imaging reveals different neural substrates for the effects of orexin-1 and orexin-2 receptor antagonists.

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Alessandro Gozzi

Full Text Available Orexins are neuro-modulatory peptides involved in the control of diverse physiological functions through interaction with two receptors, orexin-1 (OX1R and orexin-2 (OX2R. Recent evidence in pre-clinical models points toward a putative dichotomic role of the two receptors, with OX2R predominantly involved in the regulation of the sleep/wake cycle and arousal, and the OX1R being more specifically involved in reward processing and motivated behaviour. However, the specific neural substrates underlying these distinct processes in the rat brain remain to be elucidated. Here we used functional magnetic resonance imaging (fMRI in the rat to map the modulatory effect of selective OXR blockade on the functional response produced by D-amphetamine, a psychostimulant and arousing drug that stimulates orexigenic activity. OXR blockade was produced by GSK1059865 and JNJ1037049, two novel OX1R and OX2R antagonists with unprecedented selectivity at the counter receptor type. Both drugs inhibited the functional response to D-amphetamine albeit with distinct neuroanatomical patterns: GSK1059865 focally modulated functional responses in striatal terminals, whereas JNJ1037049 induced a widespread pattern of attenuation characterised by a prominent cortical involvement. At the same doses tested in the fMRI study, JNJ1037049 exhibited robust hypnotic properties, while GSK1059865 failed to display significant sleep-promoting effects, but significantly reduced drug-seeking behaviour in cocaine-induced conditioned place preference. Collectively, these findings highlight an essential contribution of the OX2R in modulating cortical activity and arousal, an effect that is consistent with the robust hypnotic effect exhibited by JNJ1037049. The subcortical and striatal pattern observed with GSK1059865 represent a possible neurofunctional correlate for the modulatory role of OX1R in controlling reward-processing and goal-oriented behaviours in the rat.

Renal and cardiac function during alpha1-beta-blockade in congestive heart failure

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Heitmann, M; Davidsen, U; Stokholm, K H

2002-01-01

The kidney and the neurohormonal systems are essential in the pathogenesis of congestive heart failure (CHF) and the physiologic response. Routine treatment of moderate to severe CHF consists of diuretics, angiotensin-converting enzyme (ACE) inhibition and beta-blockade. The need for control...... of renal function during initiation of ACE-inhibition in patients with CHF is well known. The aim of this study was to investigate whether supplementation by a combined alpha1-beta-blockade to diuretics and ACE-inhibition might improve cardiac function without reducing renal function....

Impact of Leukocyte Function-Associated Antigen-1 Blockade on Endogenous Allospecific T Cells to Multiple Minor Histocompatibility Antigen Mismatched Cardiac Allograft.

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Kwun, Jean; Farris, Alton B; Song, Hyunjin; Mahle, William T; Burlingham, William J; Knechtle, Stuart J

2015-12-01

Blocking leukocyte function-associated antigen (LFA)-1 in organ transplant recipients prolongs allograft survival. However, the precise mechanisms underlying the therapeutic potential of LFA-1 blockade in preventing chronic rejection are not fully elucidated. Cardiac allograft vasculopathy (CAV) is the preeminent cause of late cardiac allograft failure characterized histologically by concentric intimal hyperplasia. Anti-LFA-1 monoclonal antibody was used in a multiple minor antigen-mismatched, BALB.B (H-2B) to C57BL/6 (H-2B), cardiac allograft model. Endogenous donor-specific CD8 T cells were tracked down using major histocompatibility complex multimers against the immunodominant H4, H7, H13, H28, and H60 minor Ags. The LFA-1 blockade prevented acute rejection and preserved palpable beating quality with reduced CD8 T-cell graft infiltration. Interestingly, less CD8 T cell infiltration was secondary to reduction of T-cell expansion rather than less trafficking. The LFA-1 blockade significantly suppressed the clonal expansion of minor histocompatibility antigen-specific CD8 T cells during the expansion and contraction phase. The CAV development was evaluated with morphometric analysis at postoperation day 100. The LFA-1 blockade profoundly attenuated neointimal hyperplasia (61.6 vs 23.8%; P < 0.05), CAV-affected vessel number (55.3 vs 15.9%; P < 0.05), and myocardial fibrosis (grade 3.29 vs 1.8; P < 0.05). Finally, short-term LFA-1 blockade promoted long-term donor-specific regulation, which resulted in attenuated transplant arteriosclerosis. Taken together, LFA-1 blockade inhibits initial endogenous alloreactive T-cell expansion and induces more regulation. Such a mechanism supports a pulse tolerance induction strategy with anti-LFA-1 rather than long-term treatment.

Blockade of vascular adhesion protein-1 inhibits lymphocyte infiltration in rat liver allograft rejection.

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Martelius, Timi; Salaspuro, Ville; Salmi, Marko; Krogerus, Leena; Höckerstedt, Krister; Jalkanen, Sirpa; Lautenschlager, Irmeli

2004-12-01

Vascular adhesion protein-1 (VAP-1) has been shown to mediate lymphocyte adhesion to endothelia at sites of inflammation, but its functional role in vivo has not been tested in any rodent model. Here we report the effects of VAP-1 blockade on rat liver allograft rejection. BN recipients of PVG liver allografts (known to develop acute rejection by day 7) were treated with 2 mg/kg anti-VAP-1 (a new anti-rat VAP-1 mAb 174-5) or isotype-matched irrelevant antibody (NS1) every other day (n = 6/group) and one group with anti-VAP-1 2 mg/kg daily (n = 7). On day 7, samples were collected for transplant aspiration cytology, histology, and immunohistochemistry. Lymphocyte infiltration to the graft was clearly affected by VAP-blockade. The total inflammation, mainly the number of active lymphoid cells, in transplant aspiration cytology was significantly decreased in animals treated with anti-VAP-1 (4.7 +/- 1.0 and 2.4 +/- 1.0 corrected increment units, respectively) compared to control (6.6 +/- 1.0) (P VAP-1 plays an important role in lymphocyte infiltration to sites of inflammation, and, in particular, liver allograft rejection.

Effect of Angiotensin II Type I Receptor Blockade with Valsartan on Carotid Artery Atherosclerosis: A Double Blind Randomized Clinical Trial Comparing Valsartan and Placebo (EFFERVESCENT)

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Ramadan, Ronnie; Dhawan, Saurabh S.; Binongo, José Nilo G.; Alkhoder, Ayman; Jones, Dean P.; Oshinski, John N.; Quyyumi, Arshed A.

2016-01-01

Background Progression of atherosclerosis is associated with a greater risk for adverse outcomes. Angiotensin II plays a key role in the pathogenesis and progression of atherosclerosis. We aimed to investigate the effects of Angiotensin II type-1 receptor (AT1R) blockade with Valsartan on carotid wall atherosclerosis, with the hypothesis that Valsartan will reduce progression of atherosclerosis. Methods Subjects (n= 120) with carotid intima-media thickness >0.65mm by ultrasound were randomized (2:1) in a double-blind manner to receive either Valsartan or placebo for 2 years. Bilateral T2-weighted black-blood carotid magnetic resonance imaging was performed at baseline, 12 and 24 months. Changes in the carotid bulb vessel wall area (VWA) and wall thickness (WT) were primary endpoints. Secondary endpoints included changes in carotid plaque thickness, plasma levels of aminothiols, C-reactive protein, fibrinogen, and endothelium-dependent and -independent vascular function. Results Over 2 years, the carotid bulb VWA decreased with Valsartan (−6.7, 95% CI: (−11.6,−1.9) mm2) but not with placebo (3.4, 95% CI: (−2.8,9.6) mm2)), p=0.01 between groups. Similarly, mean WT decreased with Valsartan (−0.18, 95% CI: (−0.30,−0.06) mm), but not with placebo (0.08, 95% CI: (−0.07,0.23) mm),), p=0.009 between groups. Furthermore, plaque thickness decreased with Valsartan (−0.35, 95% CI: (−0.63,−0.08) mm) but was unchanged with placebo (+0.28, 95% CI: (−0.11,0.69) mm), p=0.01 between groups. These findings were unaffected by statin therapy or changes in blood pressure. Notably, there were significant improvements in the aminothiol cysteineglutathione disulfide, and trends to improvements in fibrinogen levels and endothelium–independent vascular function. Conclusions In subjects with carotid wall thickening, AT1R blockade was associated with regression in carotid atherosclerosis. Whether these effects translate into improved outcomes in subjects with

Specific Kv1.3 blockade modulates key cholesterol-metabolism-associated molecules in human macrophages exposed to ox-LDL.

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Yang, Yong; Wang, Yan-Fu; Yang, Xiao-Fang; Wang, Zhao-Hui; Lian, Yi-Tian; Yang, Ying; Li, Xiao-Wei; Gao, Xiang; Chen, Jian; Shu, Yan-Wen; Cheng, Long-Xian; Liao, Yu-Hua; Liu, Kun

2013-01-01

Cholesterol-metabolism-associated molecules, including scavenger receptor class A (SR-A), lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1), CD36, ACAT1, ABCA1, ABCG1, and scavenger receptor class B type I, can modulate cholesterol metabolism in the transformation from macrophages to foam cells. Voltage-gated potassium channel Kv1.3 has increasingly been demonstrated to play an important role in the modulation of macrophage function. Here, we investigate the role of Kv1.3 in modulating cholesterol-metabolism-associated molecules in human acute monocytic leukemia cell-derived macrophages (THP-1 macrophages) and human monocyte-derived macrophages exposed to oxidized LDL (ox-LDL). Human Kv1.3 and Kv1.5 channels (hKv1.3 and hKv1.5) are expressed in macrophages and form a heteromultimeric channel. The hKv1.3-E314 antibody that we had generated as a specific hKv1.3 blocker inhibited outward delayed rectifier potassium currents, whereas the hKv1.5-E313 antibody that we had generated as a specific hKv1.5 blocker failed. Accordingly, the hKv1.3-E314 antibody reduced percentage of cholesterol ester and enhanced apoA-I-mediated cholesterol efflux in THP-1 macrophages and human monocyte-derived macrophages exposed to ox-LDL. The hKv1.3-E314 antibody downregulated SR-A, LOX-1, and ACAT1 expression and upregulated ABCA1 expression in THP-1 macrophages and human monocyte-derived macrophages. Our results reveal that specific Kv1.3 blockade represents a novel strategy modulating cholesterol metabolism in macrophages, which benefits the treatment of atherosclerotic lesions.

Reinforcing and neurochemical effects of cannabinoid CB1 receptor agonists, but not cocaine, are altered by an adenosine A2A receptor antagonist.

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Justinová, Zuzana; Ferré, Sergi; Redhi, Godfrey H; Mascia, Paola; Stroik, Jessica; Quarta, Davide; Yasar, Sevil; Müller, Christa E; Franco, Rafael; Goldberg, Steven R

2011-07-01

Several recent studies suggest functional and molecular interactions between striatal adenosine A(2A) and cannabinoid CB(1) receptors. Here, we demonstrate that A(2A) receptors selectively modulate reinforcing effects of cannabinoids. We studied effects of A(2A) receptor blockade on the reinforcing effects of delta-9-tetrahydrocannabinol (THC) and the endogenous CB(1) receptor ligand anandamide under a fixed-ratio schedule of intravenous drug injection in squirrel monkeys. A low dose of the selective adenosine A(2A) receptor antagonist MSX-3 (1 mg/kg) caused downward shifts of THC and anandamide dose-response curves. In contrast, a higher dose of MSX-3 (3 mg/kg) shifted THC and anandamide dose-response curves to the left. MSX-3 did not modify cocaine or food pellet self-administration. Also, MSX-3 neither promoted reinstatement of extinguished drug-seeking behavior nor altered reinstatement of drug-seeking behavior by non-contingent priming injections of THC. Finally, using in vivo microdialysis in freely-moving rats, a behaviorally active dose of MSX-3 significantly counteracted THC-induced, but not cocaine-induced, increases in extracellular dopamine levels in the nucleus accumbens shell. The significant and selective results obtained with the lower dose of MSX-3 suggest that adenosine A(2A) antagonists acting preferentially at presynaptic A(2A) receptors might selectively reduce reinforcing effects of cannabinoids that lead to their abuse. However, the appearance of potentiating rather than suppressing effects on cannabinoid reinforcement at the higher dose of MSX-3 would likely preclude the use of such a compound as a medication for cannabis abuse. Adenosine A(2A) antagonists with more selectivity for presynaptic versus postsynaptic receptors could be potential medications for treatment of cannabis abuse. Addiction Biology © 2010 Society for the Study of Addiction. No claim to original US government works.

α-blockade, apoptosis, and prostate shrinkage: how are they related?

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Chłosta, Piotr; Drewa, Tomasz; Kaplan, Steven

2013-01-01

The α1-adrenoreceptor antagonists, such as terazosin and doxazosin, induce prostate programmed cell death (apoptosis) within prostate epithelial and stromal cells in vitro. This treatment should cause prostate volume decrease, However, this has never been observed in clinical conditions. The aim of this paper is to review the disconnect between these two processes. PubMed and DOAJ were searched for papers related to prostate, apoptosis, and stem cell death. The following key words were used: prostate, benign prostate hyperplasia, programmed cell death, apoptosis, cell death, α1-adrenoreceptor antagonist, α-blockade, prostate epithelium, prostate stroma, stem cells, progenitors, and in vitro models. We have shown how discoveries related to stem cells can influence our understanding of α-blockade treatment for BPH patients. Prostate epithelial and mesenchymal compartments have stem (progenitors) and differentiating cells. These compartments are described in relation to experimental in vitro and in vivo settings. Apoptosis is observed within prostate tissue, but this effect has no clinical significance and cannot lead to prostate shrinkage. In part, this is due to stem cells that are responsible for prostate tissue regeneration and are resistant to apoptosis triggered by α1-receptor antagonists.

Immunohistochemical Localization of AT1a, AT1b, and AT2 Angiotensin II Receptor Subtypes in the Rat Adrenal, Pituitary, and Brain with a Perspective Commentary

Directory of Open Access Journals (Sweden)

Courtney Premer

2013-01-01

Full Text Available Angiotensin II increases blood pressure and stimulates thirst and sodium appetite in the brain. It also stimulates secretion of aldosterone from the adrenal zona glomerulosa and epinephrine from the adrenal medulla. The rat has 3 subtypes of angiotensin II receptors: AT1a, AT1b, and AT2. mRNAs for all three subtypes occur in the adrenal and brain. To immunohistochemically differentiate these receptor subtypes, rabbits were immunized with C-terminal fragments of these subtypes to generate receptor subtype-specific antibodies. Immunofluorescence revealed AT1a and AT2 receptors in adrenal zona glomerulosa and medulla. AT1b immunofluorescence was present in the zona glomerulosa, but not the medulla. Ultrastructural immunogold labeling for the AT1a receptor in glomerulosa and medullary cells localized it to plasma membrane, endocytic vesicles, multivesicular bodies, and the nucleus. AT1b and AT2, but not AT1a, immunofluorescence was observed in the anterior pituitary. Stellate cells were AT1b positive while ovoid cells were AT2 positive. In the brain, neurons were AT1a, AT1b, and AT2 positive, but glia was only AT1b positive. Highest levels of AT1a, AT1b, and AT2 receptor immunofluorescence were in the subfornical organ, median eminence, area postrema, paraventricular nucleus, and solitary tract nucleus. These studies complement those employing different techniques to characterize Ang II receptors.

Loss of Macrophage Low-Density Lipoprotein Receptor-Related Protein 1 Confers Resistance to the Antiatherogenic Effects of Tumor Necrosis Factor-α Inhibition.

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Zhu, Lin; Giunzioni, Ilaria; Tavori, Hagai; Covarrubias, Roman; Ding, Lei; Zhang, Youmin; Ormseth, Michelle; Major, Amy S; Stafford, John M; Linton, MacRae F; Fazio, Sergio

2016-08-01

Antiatherosclerotic effects of tumor necrosis factor-α (TNF-α) blockade in patients with systemic inflammatory states are not conclusively demonstrated, which suggests that effects depend on the cause of inflammation. Macrophage LRP1 (low-density lipoprotein receptor-related protein 1) and apoE contribute to inflammation through different pathways. We studied the antiatherosclerosis effects of TNF-α blockade in hyperlipidemic mice lacking either LRP1 (MΦLRP1(-/-)) or apoE from macrophages. Lethally irradiated low-density lipoprotein receptor (LDLR)(-/-) mice were reconstituted with bone marrow from either wild-type, MΦLRP1(-/-), apoE(-/-) or apoE(-/-)/MΦLRP1(-/-)(DKO) mice, and then treated with the TNF-α inhibitor adalimumab while fed a Western-type diet. Adalimumab reduced plasma TNF-α concentration, suppressed blood ly6C(hi) monocyte levels and their migration into the lesion, and reduced lesion cellularity and inflammation in both wild-type→LDLR(-/-) and apoE(-/-)→LDLR(-/-) mice. Overall, adalimumab reduced lesion burden by 52% to 57% in these mice. Adalimumab reduced TNF-α and blood ly6C(hi) monocyte levels in MΦLRP1(-/-)→LDLR(-/-) and DKO→LDLR(-/-) mice, but it did not suppress ly6C(hi) monocyte migration into the lesion or atherosclerosis progression. Our results show that TNF-α blockade exerts antiatherosclerotic effects that are dependent on the presence of macrophage LRP1. © 2016 American Heart Association, Inc.

Blockade of the voltage-gated potassium channel Kv1.3 inhibits immune responses in vivo.

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Koo, G C; Blake, J T; Talento, A; Nguyen, M; Lin, S; Sirotina, A; Shah, K; Mulvany, K; Hora, D; Cunningham, P; Wunderler, D L; McManus, O B; Slaughter, R; Bugianesi, R; Felix, J; Garcia, M; Williamson, J; Kaczorowski, G; Sigal, N H; Springer, M S; Feeney, W

1997-06-01

The voltage activated K+ channel (Kv1.3) has recently been identified as the molecule that sets the resting membrane potential of peripheral human T lymphoid cells. In vitro studies indicate that blockage of Kv1.3 inhibits T cell activation, suggesting that Kv1.3 may be a target for immunosuppression. However, despite the in vitro evidence, there has been no in vivo demonstration that blockade of Kv1.3 will attenuate an immune response. The difficulty is due to species differences, as the channel does not set the membrane potential in rodent peripheral T cells. In this study, we show that the channel is present on peripheral T cells of miniswine. Using the peptidyl Kv1.3 inhibitor, margatoxin, we demonstrate that Kv1.3 also regulates the resting membrane potential, and that blockade of Kv1.3 inhibits, in vivo, both a delayed-type hypersensitivity reaction and an Ab response to an allogeneic challenge. In addition, prolonged Kv1.3 blockade causes reduced thymic cellularity and inhibits the thymic development of T cell subsets. These results provide in vivo evidence that Kv1.3 is a novel target for immunomodulation.

Heterogeneous Downregulation of Angiotensin II AT1-A and AT1-B Receptors in Arterioles in STZ-Induced Diabetic Rat Kidneys

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Zsolt Razga

2014-01-01

Full Text Available Introduction. The renin granulation of kidney arterioles is enhanced in diabetes despite the fact that the level of angiotensin II in the diabetic kidney is elevated. Therefore, the number of angiotensin II AT1-A and AT1-B receptors in afferent and efferent arteriole’s renin-positive and renin-negative smooth muscle cells (SMC was estimated. Method. Immunohistochemistry at the electron microscopic level was combined with 3D stereological sampling techniques. Results. In diabetes the enhanced downregulation of AT1-B receptors in the renin-positive than in the renin-negative SMCs in both arterioles was resulted: the significant difference in the number of AT1 (AT1-A + AT1-B receptors between the two types of SMCs in the normal rats was further increased in diabetes and in contrast with the significant difference observed between the afferent and efferent arterioles in the normal animals, there was no such difference in diabetes. Conclusions. The enhanced downregulation of the AT1-B receptors in the renin-negative SMCs in the efferent arterioles demonstrates that the regulation of the glomerular filtration rate by the pre- and postglomerular arterioles is changed in diabetes. The enhanced downregulation of the AT1-B receptors in the renin-positive SMCs in the arterioles may result in an enhanced level of renin granulation in the arterioles.

PD-1 Blockade Expands Intratumoral Memory T Cells

DEFF Research Database (Denmark)

Ribas, Antoni; Shin, Daniel Sanghoon; Zaretsky, Jesse

2016-01-01

by multicolor flow cytometry using two computational approaches to resolve the leukocyte phenotypes at the single-cell level. There was a statistically significant increase in the frequency of T cells in patients who responded to therapy. The frequency of intratumoral B cells and monocytic myeloid......-derived suppressor cells significantly increased in patients' biopsies taken on treatment. The percentage of cells with a regulatory T-cell phenotype, monocytes, and natural killer cells did not change while on PD-1 blockade therapy. CD8+ memory T cells were the most prominent phenotype that expanded intratumorally...... on therapy. However, the frequency of CD4+ effector memory T cells significantly decreased on treatment, whereas CD4+ effector T cells significantly increased in nonresponding tumors on therapy. In peripheral blood, an unusual population of blood cells expressing CD56 was detected in two patients...

Heterodimerization and endocytosis of Arabidopsis brassinosteroid receptors BRI1 and AtSERK3 (BAK1)

DEFF Research Database (Denmark)

Russinova, Eugenia; Borst, Jan-Willem; Kwaaitaal, Mark Adrianus Cornelis J

2004-01-01

us to localize each receptor independently in vivo. We show that BRI1, but not AtSERK3, homodimerizes in the plasma membrane, whereas BRI1 and AtSERK3 preferentially heterodimerize in the endosomes. Coexpression of BRI1 and AtSERK3 results in a change of the steady state distribution of both...... receptors because of accelerated endocytosis. Endocytic vesicles contain either BRI1 or AtSERK3 alone or both. We propose that the AtSERK3 protein is involved in changing the equilibrium between plasma membrane-located BRI1 homodimers and endocytosed BRI1-AtSERK3 heterodimers....

Synthesis and Evaluation of Orexin-1 Receptor Antagonists with Improved Solubility and CNS Permeability.

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Perrey, David A; Decker, Ann M; Zhang, Yanan

2018-03-21

Orexins are hypothalamic neuropeptides playing important roles in many functions including the motivation of addictive behaviors. Blockade of the orexin-1 receptor has been suggested as a potential strategy for the treatment of drug addiction. We have previously reported OX 1 receptor antagonists based on the tetrahydroisoquinoline scaffold with excellent OX 1 potency and selectivity; however, these compounds had high lipophilicity (clogP > 5) and low to moderate solubility. In an effort to improve their properties, we have designed and synthesized a series of analogues where the 7-position substituents known to favor OX 1 potency and selectivity were retained, and groups of different nature were introduced at the 1-position where substitution was generally tolerated as demonstrated in previous studies. Compound 44 with lower lipophilicity (clogP = 3.07) displayed excellent OX 1 potency ( K e = 5.7 nM) and selectivity (>1,760-fold over OX 2 ) in calcium mobilization assays. In preliminary ADME studies, 44 showed excellent kinetic solubility (>200 μM), good CNS permeability ( P app = 14.7 × 10 -6 cm/sec in MDCK assay), and low drug efflux (efflux ratio = 3.3).

Molecular mechanism of PD-1/PD-L1 blockade via anti-PD-L1 antibodies atezolizumab and durvalumab.

Science.gov (United States)

Lee, Hyun Tae; Lee, Ju Yeon; Lim, Heejin; Lee, Sang Hyung; Moon, Yu Jeong; Pyo, Hyo Jeong; Ryu, Seong Eon; Shin, Woori; Heo, Yong-Seok

2017-07-17

In 2016 and 2017, monoclonal antibodies targeting PD-L1, including atezolizumab, durvalumab, and avelumab, were approved by the FDA for the treatment of multiple advanced cancers. And many other anti-PD-L1 antibodies are under clinical trials. Recently, the crystal structures of PD-L1 in complex with BMS-936559 and avelumab have been determined, revealing details of the antigen-antibody interactions. However, it is still unknown how atezolizumab and durvalumab specifically recognize PD-L1, although this is important for investigating novel binding sites on PD-L1 targeted by other therapeutic antibodies for the design and improvement of anti-PD-L1 agents. Here, we report the crystal structures of PD-L1 in complex with atezolizumab and durvalumab to elucidate the precise epitopes involved and the structural basis for PD-1/PD-L1 blockade by these antibodies. A comprehensive comparison of PD-L1 interactions with anti-PD-L1 antibodies provides a better understanding of the mechanism of PD-L1 blockade as well as new insights into the rational design of improved anti-PD-L1 therapeutics.

Specific Kv1.3 blockade modulates key cholesterol-metabolism-associated molecules in human macrophages exposed to ox-LDL[S

Science.gov (United States)

Yang, Yong; Wang, Yan-Fu; Yang, Xiao-Fang; Wang, Zhao-Hui; Lian, Yi-Tian; Yang, Ying; Li, Xiao-Wei; Gao, Xiang; Chen, Jian; Shu, Yan-Wen; Cheng, Long-Xian; Liao, Yu-Hua; Liu, Kun

2013-01-01

Cholesterol-metabolism-associated molecules, including scavenger receptor class A (SR-A), lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1), CD36, ACAT1, ABCA1, ABCG1, and scavenger receptor class B type I, can modulate cholesterol metabolism in the transformation from macrophages to foam cells. Voltage-gated potassium channel Kv1.3 has increasingly been demonstrated to play an important role in the modulation of macrophage function. Here, we investigate the role of Kv1.3 in modulating cholesterol-metabolism-associated molecules in human acute monocytic leukemia cell-derived macrophages (THP-1 macrophages) and human monocyte-derived macrophages exposed to oxidized LDL (ox-LDL). Human Kv1.3 and Kv1.5 channels (hKv1.3 and hKv1.5) are expressed in macrophages and form a heteromultimeric channel. The hKv1.3-E314 antibody that we had generated as a specific hKv1.3 blocker inhibited outward delayed rectifier potassium currents, whereas the hKv1.5-E313 antibody that we had generated as a specific hKv1.5 blocker failed. Accordingly, the hKv1.3-E314 antibody reduced percentage of cholesterol ester and enhanced apoA-I-mediated cholesterol efflux in THP-1 macrophages and human monocyte-derived macrophages exposed to ox-LDL. The hKv1.3-E314 antibody downregulated SR-A, LOX-1, and ACAT1 expression and upregulated ABCA1 expression in THP-1 macrophages and human monocyte-derived macrophages. Our results reveal that specific Kv1.3 blockade represents a novel strategy modulating cholesterol metabolism in macrophages, which benefits the treatment of atherosclerotic lesions. PMID:23099443

NMDA receptor blockade alters the intracellular distribution of neuronal nitric oxide synthase in the superficial layers of the rat superior colliculus

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R.E. de Bittencourt-Navarrete

2009-02-01

Full Text Available Nitric oxide (NO is a molecular messenger involved in several events of synaptic plasticity in the central nervous system. Ca2+ influx through the N-methyl-D-aspartate receptor (NMDAR triggers the synthesis of NO by activating the enzyme neuronal nitric oxide synthase (nNOS in postsynaptic densities. Therefore, NMDAR and nNOS are part of the intricate scenario of postsynaptic densities. In the present study, we hypothesized that the intracellular distribution of nNOS in the neurons of superior colliculus (SC superficial layers is an NMDAR activity-dependent process. We used osmotic minipumps to promote chronic blockade of the receptors with the pharmacological agent MK-801 in the SC of 7 adult rats. The effective blockade of NMDAR was assessed by changes in the protein level of the immediate early gene NGFI-A, which is a well-known NMDAR activity-dependent expressing transcription factor. Upon chronic infusion of MK-801, a decrease of 47% in the number of cells expressing NGFI-A was observed in the SC of treated animals. Additionally, the filled dendritic extent by the histochemical product of nicotinamide adenine di-nucleotide phosphate diaphorase was reduced by 45% when compared to the contralateral SC of the same animals and by 64% when compared to the SC of control animals. We conclude that the proper intracellular localization of nNOS in the retinorecipient layers of SC depends on NMDAR activation. These results are consistent with the view that the participation of NO in the physiological and plastic events of the central nervous system might be closely related to an NMDAR activity-dependent function.

Enhancing virus-specific immunity in vivo by combining therapeutic vaccination and PD-L1 blockade in chronic hepadnaviral infection.

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Jia Liu

2014-01-01

Full Text Available Hepatitis B virus (HBV persistence is facilitated by exhaustion of CD8 T cells that express the inhibitory receptor programmed cell death-1 (PD-1. Improvement of the HBV-specific T cell function has been obtained in vitro by inhibiting the PD-1/PD-ligand 1 (PD-L1 interaction. In this study, we examined whether in vivo blockade of the PD-1 pathway enhances virus-specific T cell immunity and leads to the resolution of chronic hepadnaviral infection in the woodchuck model. The woodchuck PD-1 was first cloned, characterized, and its expression patterns on T cells from woodchucks with acute or chronic woodchuck hepatitis virus (WHV infection were investigated. Woodchucks chronically infected with WHV received a combination therapy with nucleoside analogue entecavir (ETV, therapeutic DNA vaccination and woodchuck PD-L1 antibody treatment. The gain of T cell function and the suppression of WHV replication by this therapy were evaluated. We could show that PD-1 expression on CD8 T cells was correlated with WHV viral loads during WHV infection. ETV treatment significantly decreased PD-1 expression on CD8 T cells in chronic carriers. In vivo blockade of PD-1/PD-L1 pathway on CD8 T cells, in combination with ETV treatment and DNA vaccination, potently enhanced the function of virus-specific T cells. Moreover, the combination therapy potently suppressed WHV replication, leading to sustained immunological control of viral infection, anti-WHs antibody development and complete viral clearance in some woodchucks. Our results provide a new approach to improve T cell function in chronic hepatitis B infection, which may be used to design new immunotherapeutic strategies in patients.

Blockade by phenoxybenzamine of the contractor response produced by agonists in the isolated ileum of the guinea-pig.

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Cook, D A

1971-09-01

1. The effects of various concentrations of phenoxybenzamine (dibenzyline) on the contractor response of the isolated ileum of the guinea-pig were investigated. The agonists tested were histamine, 5-hydroxytryptamine (5-HT), acetycholine and potassium chloride.2. In addition, uptake of (14)C-phenoxybenzamine into the ileum was determined as a function of antagonist concentration. The uptake increases sharply at concentrations above 10(-6) g/ml, (3x10(-6)M) and was not saturable at any concentration tested.3. In the presence of low concentrations of phenoxybenzamine, the dose-response curve for histamine undergoes a parallel shift of about 0.5 log units. At higher concentrations of phenoxybenzamine the maximum response is depressed. In the case of the other agonists, the maximum response is depressed as soon as any blockade becomes apparent.4. The ease of blockade with phenoxybenzamine is 5-HT >/= histamine> acetylcholine >/= potassium chloride.5. These results do not lend support to the ;spare-receptor' hypothesis and may be better explained by the ;two-site' hypothesis of Moran & Triggle (1970).6. It may further be concluded that the successful antagonism of potassium-induced contractions in this preparation lies in the ability of phenoxybenzamine to prevent the action of released acetylcholine. In the case of the contraction induced by 5-HT, phenoxybenzamine probably interferes with the 5-HT receptor responsible for neuronal release of acetycholine.

Do serotonin(1-7) receptors modulate short and long-term memory?

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Meneses, A

2007-05-01

Evidence from invertebrates to human studies indicates that serotonin (5-hydroxytryptamine; 5-HT) system modulates short- (STM) and long-term memory (LTM). This work is primarily focused on analyzing the contribution of 5-HT, cholinergic and glutamatergic receptors as well as protein synthesis to STM and LTM of an autoshaping learning task. It was observed that the inhibition of hippocampal protein synthesis or new mRNA did not produce a significant effect on autoshaping STM performance but it did impair LTM. Both non-contingent protein inhibition and 5-HT depletion showed no effects. It was basically the non-selective 5-HT receptor antagonist cyproheptadine, which facilitated STM. However, the blockade of glutamatergic and cholinergic transmission impaired STM. In contrast, the selective 5-HT(1B) receptor antagonist SB-224289 facilitated both STM and LTM. Selective receptor antagonists for the 5-HT(1A) (WAY100635), 5-HT(1D) (GR127935), 5-HT(2A) (MDL100907), 5-HT(2C/2B) (SB-200646), 5-HT(3) (ondansetron) or 5-HT(4) (GR125487), 5-HT(6) (Ro 04-6790, SB-399885 and SB-35713) or 5-HT(7) (SB-269970) did not impact STM. Nevertheless, WAY100635, MDL100907, SB-200646, GR125487, Ro 04-6790, SB-399885 or SB-357134 facilitated LTM. Notably, some of these changes shown to be independent of food-intake. Concomitantly, these data indicate that '5-HT tone via 5-HT(1B) receptors' might function in a serial manner from STM to LTM, whereas working in parallel using 5-HT(1A), 5-HT(2A), 5-HT(2B/2C), 5-HT(4), or 5-HT(6) receptors.

The role of dopamine receptors in the neurotoxicity of methamphetamine.

Science.gov (United States)

Ares-Santos, S; Granado, N; Moratalla, R

2013-05-01

Methamphetamine is a synthetic drug consumed by millions of users despite its neurotoxic effects in the brain, leading to loss of dopaminergic fibres and cell bodies. Moreover, clinical reports suggest that methamphetamine abusers are predisposed to Parkinson's disease. Therefore, it is important to elucidate the mechanisms involved in methamphetamine-induced neurotoxicity. Dopamine receptors may be a plausible target to prevent this neurotoxicity. Genetic inactivation of dopamine D1 or D2 receptors protects against the loss of dopaminergic fibres in the striatum and loss of dopaminergic neurons in the substantia nigra. Protection by D1 receptor inactivation is due to blockade of hypothermia, reduced dopamine content and turnover and increased stored vesicular dopamine in D1R(-/-) mice. However, the neuroprotective impact of D2 receptor inactivation is partially dependent on an effect on body temperature, as well as on the blockade of dopamine reuptake by decreased dopamine transporter activity, which results in reduced intracytosolic dopamine levels in D2R(-/-) mice. © 2013 The Association for the Publication of the Journal of Internal Medicine.

Radiotherapy and immune checkpoint blockades: a snapshot in 2016

Energy Technology Data Exchange (ETDEWEB)

Koo, Tae Yool [Dept. of Radiation Oncology, Hallym University Chuncheon Sacred Heart Hospital, Chuncheon (Korea, Republic of); Kim, In Ah [Dept. of Radiation Oncology, Seoul National University College of Medicine, Seoul (Korea, Republic of)

2016-12-15

Immune checkpoint blockades including monoclonal antibodies (mAbs) of cytotoxic T-lymphocyte antigen-4 (CTLA-4), programmed death-1 (PD-1), and programmed death-ligand 1 (PD-L1) have been emerged as a promising anticancer therapy. Several immune checkpoint blockades have been approved by US Food and Drug Administration (FDA), and have shown notable success in clinical trials for patients with advanced melanoma and non-small cell lung cancer. Radiotherapy is a promising combination partner of immune checkpoint blockades due to its potent pro-immune effect. This review will cover the current issue and the future perspectives for combined with radiotherapy and immune checkpoint blockades based upon the available preclinical and clinical data.

Blockade of Vascular Adhesion Protein-1 Inhibits Lymphocyte Infiltration in Rat Liver Allograft Rejection

OpenAIRE

Martelius, Timi; Salaspuro, Ville; Salmi, Marko; Krogerus, Leena; Höckerstedt, Krister; Jalkanen, Sirpa; Lautenschlager, Irmeli

2004-01-01

Vascular adhesion protein-1 (VAP-1) has been shown to mediate lymphocyte adhesion to endothelia at sites of inflammation, but its functional role in vivo has not been tested in any rodent model. Here we report the effects of VAP-1 blockade on rat liver allograft rejection. BN recipients of PVG liver allografts (known to develop acute rejection by day 7) were treated with 2 mg/kg anti-VAP-1 (a new anti-rat VAP-1 mAb 174–5) or isotype-matched irrelevant antibody (NS1) every other day (n = 6/gro...

TAM receptor tyrosine kinases as emerging targets of innate immune checkpoint blockade for cancer therapy.

Science.gov (United States)

Akalu, Yemsratch T; Rothlin, Carla V; Ghosh, Sourav

2017-03-01

Cancer immunotherapy utilizing T-cell checkpoint inhibitors has shown tremendous clinical success. Yet, this mode of treatment is effective in only a subset of patients. Unresponsive patients tend to have non-T-cell-inflamed tumors that lack markers associated with the activation of adaptive anti-tumor immune responses. Notably, elimination of cancer cells by T cells is critically dependent on the optimal activity of innate immune cells. Therefore, identifying new targets that regulate innate immune cell function and promote the engagement of adaptive tumoricidal responses is likely to lead to the development of improved therapies against cancer. Here, we review the TAM receptor tyrosine kinases-TYRO3, AXL, and MERTK-as an emerging class of innate immune checkpoints that participate in key steps of anti-tumoral immunity. Namely, TAM-mediated efferocytosis, negative regulation of dendritic cell activity, and dysregulated production of chemokines collectively favor the escape of malignant cells. Hence, disabling TAM signaling may promote engagement of adaptive immunity and complement T-cell checkpoint blockade. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Evaluation of stereoisomers of 4-fluoroalkyl analogues of 3-quinuclidinyl benzilate in in vivo competition studies for the M1, M2, and M3 muscarinic receptor subtypes in brain

International Nuclear Information System (INIS)

Kiesewetter, Dale O.; Eckelman, William C.; Jaetae, Lee; Paik, Chang H.; Park, Seok G.

1995-01-01

To develop a subtype selective muscarinic acetylcholine receptor (mAChR) antagonist for PET, fluorine-19 labeled alkyl analogues of quinuclidinyl benzilate (QNB) were synthesized by stereoselective reactions. To investigate these analogues for tissue subtype specificity, in vivo competitive binding studies were performed in rat brain using (R)-3-quinuclidinyl (R)-4-[ 125 I]Iodobenzilate (IQNB). Five, fifty, or five-hundred nmol of the non-radioactive ligands were coinjected intravenously with 8 pmol of the radioligand. Cold (R,R)-IQNB blocked (R,R)-[ 125 I]IQNB in a dose-dependent manner, without showing regional specificity. For the (R,S)-fluoromethyl, -fluoroethyl, and -fluoropropyl derivatives, a higher percent blockade was seen at 5 and 50 nmol levels in M2 predominant tissues (medulla, pons, and cerebellum) than in M1 predominant tissues (cortex, striatum and hippocampus). The blockade pattern of the radioligand also correlated qualitatively with the percentage of M2 receptors in the region. The S-quinuclidinyl analogues showed M2 selectivity but less efficient blockade of the radioligand, indicating lower affinities. Radioligand bound to the medulla was inversely correlated to the M2 relative binding affinity of the fluoroalkyl analogues. These results indicate that the nonradioactive ligand blocks the radioligand based on the affinity of the nonradioactive ligand for a particular receptor subtype compared to the affinity of the radioligand for the same receptor subtype. Of the seven compounds evaluated, (R,S)-fluoromethyl-QNB appears to show the most selectivity for the M2 subtypes in competition studies in vivo

Characterization of Angiotensin II Molecular Determinants Involved in AT1 Receptor Functional Selectivity.

Science.gov (United States)

Domazet, Ivana; Holleran, Brian J; Richard, Alexandra; Vandenberghe, Camille; Lavigne, Pierre; Escher, Emanuel; Leduc, Richard; Guillemette, Gaétan

2015-06-01

The octapeptide angiotensin II (AngII) exerts a variety of cardiovascular effects through the activation of the AngII type 1 receptor (AT1), a G protein-coupled receptor. The AT1 receptor engages and activates several signaling pathways, including heterotrimeric G proteins Gq and G12, as well as the extracellular signal-regulated kinases (ERK) 1/2 pathway. Additionally, following stimulation, βarrestin is recruited to the AT1 receptor, leading to receptor desensitization. It is increasingly recognized that specific ligands selectively bind and favor the activation of some signaling pathways over others, a concept termed ligand bias or functional selectivity. A better understanding of the molecular basis of functional selectivity may lead to the development of better therapeutics with fewer adverse effects. In the present study, we developed assays allowing the measurement of six different signaling modalities of the AT1 receptor. Using a series of AngII peptide analogs that were modified in positions 1, 4, and 8, we sought to better characterize the molecular determinants of AngII that underlie functional selectivity of the AT1 receptor in human embryonic kidney 293 cells. The results reveal that position 1 of AngII does not confer functional selectivity, whereas position 4 confers a bias toward ERK signaling over Gq signaling, and position 8 confers a bias toward βarrestin recruitment over ERK activation and Gq signaling. Interestingly, the analogs modified in position 8 were also partial agonists of the protein kinase C (PKC)-dependent ERK pathway via atypical PKC isoforms PKCζ and PKCι. Copyright © 2015 by The American Society for Pharmacology and Experimental Therapeutics.

Differential actions of antiparkinson agents at multiple classes of monoaminergic receptor. III. Agonist and antagonist properties at serotonin, 5-HT(1) and 5-HT(2), receptor subtypes.

Science.gov (United States)

Newman-Tancredi, Adrian; Cussac, Didier; Quentric, Yann; Touzard, Manuelle; Verrièle, Laurence; Carpentier, Nathalie; Millan, Mark J

2002-11-01

Although certain antiparkinson agents interact with serotonin (5-HT) receptors, little information is available concerning functional actions. Herein, we characterized efficacies of apomorphine, bromocriptine, cabergoline, lisuride, piribedil, pergolide, roxindole, and terguride at human (h)5-HT(1A), h5-HT(1B), and h5-HT(1D) receptors [guanosine 5'-O-(3-[(35)S]thio)triphosphate ([(35)S]GTPgammaS) binding], and at h5-HT(2A), h5-HT(2B), and h5-HT(2C) receptors (depletion of membrane-bound [(3)H]phosphatydilinositol). All drugs stimulated h5-HT(1A) receptors with efficacies (compared with 5-HT, 100%) ranging from modest (apomorphine, 35%) to high (cabergoline, 93%). At h5-HT(1B) receptors, efficacies varied from mild (terguride, 37%) to marked (cabergoline, 102%) and potencies were modest (pEC(50) values of 5.8-7.6): h5-HT(1D) sites were activated with a similar range of efficacies and greater potency (7.1-8.5). Piribedil and apomorphine were inactive at h5-HT(1B) and h5-HT(1D) receptors. At h5-HT(2A) receptors, terguride, lisuride, bromocriptine, cabergoline, and pergolide displayed potent (7.6-8.8) agonist properties (49-103%), whereas apomorphine and roxindole were antagonists and piribedil was inactive. Only pergolide (113%/8.2) and cabergoline (123%/8.6) displayed pronounced agonist properties at h5-HT(2B) receptors. At 5-HT(2C) receptors, lisuride, bromocriptine, pergolide, and cabergoline were efficacious (75-96%) agonists, apomorphine and terguride were antagonists, and piribedil was inactive. MDL100,907 and SB242,084, selective antagonists at 5-HT(2A) and 5-HT(2C) receptors, respectively, abolished these actions of pergolide, cabergoline, and bromocriptine. In conclusion, antiparkinson agents display markedly different patterns of agonist and antagonist properties at multiple 5-HT receptor subtypes. Although all show modest (agonist) activity at 5-HT(1A) sites, their contrasting actions at 5-HT(2A) and 5-HT(2C) sites may be of particular significance to their

Bone Marrow Suppression by c-Kit Blockade Enhances Tumor Growth of Colorectal Metastases through the Action of Stromal Cell-Derived Factor-1

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Kathrin Rupertus

2012-01-01

Full Text Available Background. Mobilization of c-Kit+ hematopoietic cells (HCs contributes to tumor vascularization. Whereas survival and proliferation of HCs are regulated by binding of the stem cell factor to its receptor c-Kit, migration of HCs is directed by stromal cell-derived factor (SDF-1. Therefore, targeting migration of HCs provides a promising new strategy of anti-tumor therapy. Methods. BALB/c mice (=16 were pretreated with an anti-c-Kit antibody followed by implantation of CT26.WT-GFP colorectal cancer cells into dorsal skinfold chambers. Animals (=8 additionally received a neutralizing anti-SDF-1 antibody. Animals (=8 treated with a control antibody served as controls. Investigations were performed using intravital fluorescence microscopy, immunohistochemistry, flow cytometry and western blot analysis. Results. Blockade of c-Kit significantly enhanced tumor cell engraftment compared to controls due to stimulation of tumor cell proliferation and invasion without markedly affecting tumor vascularization. C-Kit blockade significantly increased VEGF and CXCR4 expression within the growing tumors. Neutralization of SDF-1 completely antagonized this anti-c-Kit-associated tumor growth by suppression of tumor neovascularization, inhibition of tumor cell proliferation and reduction of muscular infiltration. Conclusion. Our study indicates that bone marrow suppression via anti-c-Kit pretreatment enhances tumor cell engraftment of colorectal metastases due to interaction with the SDF-1/CXCR4 pathway which is involved in HC-mediated tumor angiogenesis.

Cardiac Alpha1-Adrenergic Receptors: Novel Aspects of Expression, Signaling Mechanisms, Physiologic Function, and Clinical Importance

Science.gov (United States)

O’Connell, Timothy D.; Jensen, Brian C.; Baker, Anthony J.

2014-01-01

Adrenergic receptors (AR) are G-protein-coupled receptors (GPCRs) that have a crucial role in cardiac physiology in health and disease. Alpha1-ARs signal through Gαq, and signaling through Gq, for example, by endothelin and angiotensin receptors, is thought to be detrimental to the heart. In contrast, cardiac alpha1-ARs mediate important protective and adaptive functions in the heart, although alpha1-ARs are only a minor fraction of total cardiac ARs. Cardiac alpha1-ARs activate pleiotropic downstream signaling to prevent pathologic remodeling in heart failure. Mechanisms defined in animal and cell models include activation of adaptive hypertrophy, prevention of cardiac myocyte death, augmentation of contractility, and induction of ischemic preconditioning. Surprisingly, at the molecular level, alpha1-ARs localize to and signal at the nucleus in cardiac myocytes, and, unlike most GPCRs, activate “inside-out” signaling to cause cardioprotection. Contrary to past opinion, human cardiac alpha1-AR expression is similar to that in the mouse, where alpha1-AR effects are seen most convincingly in knockout models. Human clinical studies show that alpha1-blockade worsens heart failure in hypertension and does not improve outcomes in heart failure, implying a cardioprotective role for human alpha1-ARs. In summary, these findings identify novel functional and mechanistic aspects of cardiac alpha1-AR function and suggest that activation of cardiac alpha1-AR might be a viable therapeutic strategy in heart failure. PMID:24368739

Radiolabelled GLP-1 receptor antagonist binds to GLP-1 receptor-expressing human tissues

International Nuclear Information System (INIS)

Waser, Beatrice; Reubi, Jean Claude

2014-01-01

Radiolabelled glucagon-like peptide 1 (GLP-1) receptor agonists have recently been shown to successfully image benign insulinomas in patients. For the somatostatin receptor targeting of tumours, however, it was recently reported that antagonist tracers were superior to agonist tracers. The present study therefore evaluated various forms of the 125 iodinated-Bolton-Hunter (BH)-exendin(9-39) antagonist tracer for the in vitro visualization of GLP-1 receptor-expressing tissues in rats and humans and compared it with the agonist tracer 125 I-GLP-1(7-36)amide. Receptor autoradiography studies with 125 I-GLP-1(7-36)amide agonist or 125 I-BH-exendin(9-39) antagonist radioligands were performed in human and rat tissues. The antagonist 125 I-BH-exendin(9-39) labelled at lysine 19 identifies all human and rat GLP-1 target tissues and GLP-1 receptor-expressing tumours. Binding is of high affinity and is comparable in all tested tissues in its binding properties with the agonist tracer 125 I-GLP-1(7-36)amide. For comparison, 125 I-BH-exendin(9-39) with the BH labelled at lysine 4 did identify the GLP-1 receptor in rat tissues but not in human tissues. The GLP-1 receptor antagonist exendin(9-39) labelled with 125 I-BH at lysine 19 is an excellent GLP-1 radioligand that identifies human and rat GLP-1 receptors in normal and tumoural tissues. It may therefore be the molecular basis to develop suitable GLP-1 receptor antagonist radioligands for in vivo imaging of GLP-1 receptor-expressing tissues in patients. (orig.)

Sympatho-inhibitory properties of various AT1 receptor antagonists

NARCIS (Netherlands)

Balt, Jippe C.; Mathy, Marie-Jeanne; Pfaffendorf, Martin; van Zwieten, Peter A.

2002-01-01

It is well known that angiotensin II (Ang II) can facilitate the effects of sympathetic neurotransmission. In the present study, using various experimental models, we investigated the inhibitory effects of several Ang II subtype 1 receptor (AT1) antagonists on this Ang II-induced facilitation. We

Significant blockade of multiple receptor tyrosine kinases by MGCD516 (Sitravatinib), a novel small molecule inhibitor, shows potent anti-tumor activity in preclinical models of sarcoma.

Science.gov (United States)

Patwardhan, Parag P; Ivy, Kathryn S; Musi, Elgilda; de Stanchina, Elisa; Schwartz, Gary K

2016-01-26

Sarcomas are rare but highly aggressive mesenchymal tumors with a median survival of 10-18 months for metastatic disease. Mutation and/or overexpression of many receptor tyrosine kinases (RTKs) including c-Met, PDGFR, c-Kit and IGF1-R drive defective signaling pathways in sarcomas. MGCD516 (Sitravatinib) is a novel small molecule inhibitor targeting multiple RTKs involved in driving sarcoma cell growth. In the present study, we evaluated the efficacy of MGCD516 both in vitro and in mouse xenograft models in vivo. MGCD516 treatment resulted in significant blockade of phosphorylation of potential driver RTKs and induced potent anti-proliferative effects in vitro. Furthermore, MGCD516 treatment of tumor xenografts in vivo resulted in significant suppression of tumor growth. Efficacy of MGCD516 was superior to imatinib and crizotinib, two other well-studied multi-kinase inhibitors with overlapping target specificities, both in vitro and in vivo. This is the first report describing MGCD516 as a potent multi-kinase inhibitor in different models of sarcoma, superior to imatinib and crizotinib. Results from this study showing blockade of multiple driver signaling pathways provides a rationale for further clinical development of MGCD516 for the treatment of patients with soft-tissue sarcoma.

Group III mGlu receptor agonists potentiate the anticonvulsant effect of AMPA and NMDA receptor block.

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De Sarro, Giovambattista; Chimirri, Alba; Meldrum, Brian S

2002-09-06

We report the anticonvulsant action in DBA/2 mice of two mGlu Group III receptor agonists: (R,S)-4-phosphonophenylglycine, (R,S)-PPG, a compound with moderate mGlu8 selectivity, and of (1S,3R,4S)-1-aminocyclopentane-1,2,4-tricarboxylic acid, ACPT-1, a selective agonist for mGlu4alpha receptors. Both compounds, given intracerebroventricularly at doses which did not show marked anticonvulsant activity, produced a consistent shift to the left of the dose-response curves (i.e. enhanced the anticonvulsant properties) of 1-(4'-aminophenyl)-3,5-dihydro-7,8-dimethoxy-4H-2,3-benzodiazepin-4-one hydrochloride, CFM-2, a noncompetitive AMPA receptor antagonist, and 3-((+/-)-2-carboxypiperazin-4-yl)-1-phosphonic acid, CPPene, a competitive NMDA receptor antagonist, in DBA/2 mice. In addition, (R,S)-PPG and ACPT-1 administered intracerebroventricularly prolonged the time course of the anticonvulsant properties of CFM-2 (33 micromol/kg, i.p.) and CPPene (3.3 micromol/kg, i.p.) administered intraperitoneally. We conclude that modest reduction of synaptic glutamate release by activation of Group III metabotropic receptors potentiates the anticonvulsant effect of AMPA and NMDA receptor blockade. Copyright 2002 Elsevier Science B.V.

Dopamine Receptor-Specific Contributions to the Computation of Value.

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Burke, Christopher J; Soutschek, Alexander; Weber, Susanna; Raja Beharelle, Anjali; Fehr, Ernst; Haker, Helene; Tobler, Philippe N

2018-05-01

Dopamine is thought to play a crucial role in value-based decision making. However, the specific contributions of different dopamine receptor subtypes to the computation of subjective value remain unknown. Here we demonstrate how the balance between D1 and D2 dopamine receptor subtypes shapes subjective value computation during risky decision making. We administered the D2 receptor antagonist amisulpride or placebo before participants made choices between risky options. Compared with placebo, D2 receptor blockade resulted in more frequent choice of higher risk and higher expected value options. Using a novel model fitting procedure, we concurrently estimated the three parameters that define individual risk attitude according to an influential theoretical account of risky decision making (prospect theory). This analysis revealed that the observed reduction in risk aversion under amisulpride was driven by increased sensitivity to reward magnitude and decreased distortion of outcome probability, resulting in more linear value coding. Our data suggest that different components that govern individual risk attitude are under dopaminergic control, such that D2 receptor blockade facilitates risk taking and expected value processing.

Pan-Cancer Analyses of the Nuclear Receptor Superfamily

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Mark D. Long

2015-12-01

Full Text Available Nuclear receptors (NR act as an integrated conduit for environmental and hormonal signals to govern genomic responses, which relate to cell fate decisions. We review how their integrated actions with each other, shared co-factors and other transcription factors are disrupted in cancer. Steroid hormone nuclear receptors are oncogenic drivers in breast and prostate cancer and blockade of signaling is a major therapeutic goal. By contrast to blockade of receptors, in other cancers enhanced receptor function is attractive, as illustrated initially with targeting of retinoic acid receptors in leukemia. In the post-genomic era large consortia, such as The Cancer Genome Atlas, have developed a remarkable volume of genomic data with which to examine multiple aspects of nuclear receptor status in a pan-cancer manner. Therefore to extend the review of NR function we have also undertaken bioinformatics analyses of NR expression in over 3000 tumors, spread across six different tumor types (bladder, breast, colon, head and neck, liver and prostate. Specifically, to ask how the NR expression was distorted (altered expression, mutation and CNV we have applied bootstrapping approaches to simulate data for comparison, and also compared these NR findings to 12 other transcription factor families. Nuclear receptors were uniquely and uniformly downregulated across all six tumor types, more than predicted by chance. These approaches also revealed that each tumor type had a specific NR expression profile but these were most similar between breast and prostate cancer. Some NRs were down-regulated in at least five tumor types (e.g., NR3C2/MR and NR5A2/LRH-1 whereas others were uniquely down-regulated in one tumor (e.g., NR1B3/RARG. The downregulation was not driven by copy number variation or mutation and epigenetic mechanisms maybe responsible for the altered nuclear receptor expression.

Genetic blockade of insulin-like growth factor-1 receptor via recombinant adenovirus in lung cancer can be enhanced by the histone deacetylase inhibitor, vorinostat.

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Park, Mi-Young; Kim, Dal Rae; Eo, Eun Young; Lim, Hyo Jeong; Park, Jong Sun; Cho, Young-Jae; Yoon, Ho-Il; Lee, Jae Ho; Lee, Choon-Taek

2013-01-01

Many approaches have been suggested as anti-tumor therapy for targeting insulin-like growth factor 1 receptor (IGF-1R), such as monoclonal antibodies and tyrosine kinase inhibitor. We introduced recombinant adenoviruses expressing antisense, dominant negative or short hairpin RNA to IGF-1R. Moreover, we demonstrated that histone deacetylase inhibitor (vorinostat) can increase the transduction efficiency of adenoviruses by increasing CAR-induced transduction and by enhancing the transcription of the adenoviral transgene. In the present study, we showed that the combination of ad-sh (short hairpin) IGF-1R with vorinostat leads to a synergistic enhancement of IGF-1R blockade. We measured the change in IGF-1R upon cotreatment with vorinostat and ad-shIGF-1R. Changes in transduction efficiency of ad-shIGF-1R were measured by fluorescent microscopy. Changes in apoptotic proportion and cell survival after the cotreatment were measured by the sub-G1 assay and cell counts. The effect of nuclear factor (NF)-κB activation was also measured by NF-κB p65 activation enzyme-linked immunosorbent assay. Drug interactions were analyzed upon cotreatment with ad-shIGF-1R, vorinostat and cisplatin. Combined treatment of ad-shIGF-1R and vorinostat synergistically suppressed the IGF-1R expression in lung cancer cell lines and also increased the transduction efficiency of ad-shIGF-1R. Ad-shIGF-1R and vorinostat cotreatment increased apoptotic cell death and synergistically suppressed cell growth compared to ad-shIGF-1R or vorinostat treatment alone. Vorinostat suppressed NF-κB activation, which was activated by ad-shIGF-1R. Moreover, triple combination of ad-shIGF-1R, vorinostat and cisplatin demonstrated synergistic cytotoxicity on lung cancer cells. Vorinostat enhanced the blocking capability of ad-shIGF-1R. The combined treatment of vorinostat and ad-sh-IGF-1R appears to have promising potential as a new therapeutic approach for lung cancer. Copyright © 2013 John Wiley & Sons, Ltd.

Differential control of MMP and t-PA/PAI-1 expressions by sympathetic and renin-angiotensin systems in rat left ventricle.

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Dab, Houcine; Hachani, Rafik; Hodroj, Wassim; Sakly, Mohsen; Bricca, Giampiero; Kacem, Kamel

2009-10-05

In the present study, we tested the hypothesis that angiotensin II (Ang II) has both direct (via AT1 receptors) and indirect (via sympathostimulator pathway) actions on the synthesis and activity of the enzymes involved in the extracellular matrix degradation in vivo. For this purpose, sympathectomy and blockade of the Ang II receptor AT1 were performed alone or in combination in normotensive rats. The mRNA of the plasminogen activator (t-PA) and its inhibitor (PAI-1), the mRNA, protein and activity of the matrix metalloproteinases MMP-2 and MMP-9 were examined by Q-RT-PCR, immunoblotting and zymographic methods in the left ventricle. t-PA and PAI-1 mRNA were decreased after sympathectomy and remained unchanged after AT1 receptors blockade. mRNA was increased for t-PA and decreased by similar degree for PAI-1 after double treatment. MMPs mRNA and protein levels were decreased either after sympathectomy or AT1 receptors blockade and an additive effect was acquired after double treatment. MMPs activity was decreased by similar degree in the three treated groups. Deducted interpretations from our experimental approach suggest that Ang II inhibits directly (via AT1 receptors) and indirectly (via sympathostimulator pathway) t-PA mRNA synthesis. It seems unable to influence directly PAI-1 mRNA, but stimulates indirectly PAI-1 mRNA synthesis. Ang II stimulates directly (via AT1 receptors) and indirectly (via sympathostimulator pathway) MMPs synthesis at both transcriptional and protein levels. The enzymatic activity of MMPs does not seem to be influenced directly by Ang II but it could be stimulated indirectly (via sympathostimulator pathway).

Radiolabelled GLP-1 receptor antagonist binds to GLP-1 receptor-expressing human tissues

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Waser, Beatrice; Reubi, Jean Claude [University of Berne, Division of Cell Biology and Experimental Cancer Research, Institute of Pathology, PO Box 62, Berne (Switzerland)

2014-06-15

Radiolabelled glucagon-like peptide 1 (GLP-1) receptor agonists have recently been shown to successfully image benign insulinomas in patients. For the somatostatin receptor targeting of tumours, however, it was recently reported that antagonist tracers were superior to agonist tracers. The present study therefore evaluated various forms of the {sup 125}iodinated-Bolton-Hunter (BH)-exendin(9-39) antagonist tracer for the in vitro visualization of GLP-1 receptor-expressing tissues in rats and humans and compared it with the agonist tracer {sup 125}I-GLP-1(7-36)amide. Receptor autoradiography studies with {sup 125}I-GLP-1(7-36)amide agonist or {sup 125}I-BH-exendin(9-39) antagonist radioligands were performed in human and rat tissues. The antagonist {sup 125}I-BH-exendin(9-39) labelled at lysine 19 identifies all human and rat GLP-1 target tissues and GLP-1 receptor-expressing tumours. Binding is of high affinity and is comparable in all tested tissues in its binding properties with the agonist tracer {sup 125}I-GLP-1(7-36)amide. For comparison, {sup 125}I-BH-exendin(9-39) with the BH labelled at lysine 4 did identify the GLP-1 receptor in rat tissues but not in human tissues. The GLP-1 receptor antagonist exendin(9-39) labelled with {sup 125}I-BH at lysine 19 is an excellent GLP-1 radioligand that identifies human and rat GLP-1 receptors in normal and tumoural tissues. It may therefore be the molecular basis to develop suitable GLP-1 receptor antagonist radioligands for in vivo imaging of GLP-1 receptor-expressing tissues in patients. (orig.)

Lower lid entropion secondary to treatment with alpha-1a receptor antagonist: a case report

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Simcock Peter

2010-03-01

Full Text Available Abstract Introduction The use of alpha-1a receptor antagonists (tamsulosin is widely accepted in the treatment of benign prostatic hypertrophy (BPH. It has previously been implicated as a causative agent in intra-operative floppy iris syndrome due to its effects on the smooth muscle. We report a case of lower lid entropion that may be related to a patient commencing treatment of tamsulosin. Case presentation A 74-year-old Caucasian man was started on alpha 1-a receptor antagonist (Tamsulosin treatment for benign prostatic hypertrophy. Eight days later, he presented to the ophthalmology unit with a right lower lid entropion which was successfully treated surgically with a Weiss procedure. Conclusion We report a case of lower lid entropion that may be secondary to the recent use of an alpha-1a blocker (tamsulosin. This can be explained by considering the effect of autonomic blockade on alpha-1 receptors in the Muller's muscle on a patient that may already have an anatomical predisposition to entropion formation due to a further reduction in muscle tone.

Involvement of Striatal Cholinergic Interneurons and M1 and M4 Muscarinic Receptors in Motor Symptoms of Parkinson's Disease.

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Ztaou, Samira; Maurice, Nicolas; Camon, Jeremy; Guiraudie-Capraz, Gaëlle; Kerkerian-Le Goff, Lydia; Beurrier, Corinne; Liberge, Martine; Amalric, Marianne

2016-08-31

Over the last decade, striatal cholinergic interneurons (ChIs) have reemerged as key actors in the pathophysiology of basal-ganglia-related movement disorders. However, the mechanisms involved are still unclear. In this study, we address the role of ChI activity in the expression of parkinsonian-like motor deficits in a unilateral nigrostriatal 6-hydroxydopamine (6-OHDA) lesion model using optogenetic and pharmacological approaches. Dorsal striatal photoinhibition of ChIs in lesioned ChAT(cre/cre) mice expressing halorhodopsin in ChIs reduces akinesia, bradykinesia, and sensorimotor neglect. Muscarinic acetylcholine receptor (mAChR) blockade by scopolamine produces similar anti-parkinsonian effects. To decipher which of the mAChR subtypes provides these beneficial effects, systemic and intrastriatal administration of the selective M1 and M4 mAChR antagonists telenzepine and tropicamide, respectively, were tested in the same model of Parkinson's disease. The two compounds alleviate 6-OHDA lesion-induced motor deficits. Telenzepine produces its beneficial effects by blocking postsynaptic M1 mAChRs expressed on medium spiny neurons (MSNs) at the origin of the indirect striatopallidal and direct striatonigral pathways. The anti-parkinsonian effects of tropicamide were almost completely abolished in mutant lesioned mice that lack M4 mAChRs specifically in dopamine D1-receptor-expressing neurons, suggesting that postsynaptic M4 mAChRs expressed on direct MSNs mediate the antiakinetic action of tropicamide. The present results show that altered cholinergic transmission via M1 and M4 mAChRs of the dorsal striatum plays a pivotal role in the occurrence of motor symptoms in Parkinson's disease. The striatum, where dopaminergic and cholinergic systems interact, is the pivotal structure of basal ganglia involved in pathophysiological changes underlying Parkinson's disease. Here, using optogenetic and pharmacological approaches, we investigated the involvement of striatal

Blockade of Endothelin-1 Receptor Type B Ameliorates Glucose Intolerance and Insulin Resistance in a Mouse Model of Obstructive Sleep Apnea

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Jan Polak

2018-05-01

Full Text Available Obstructive sleep apnea (OSA is associated with insulin resistance (IR and glucose intolerance. Elevated endothelin-1 (ET-1 levels have been observed in OSA patients and in mice exposed to intermittent hypoxia (IH. We examined whether pharmacological blockade of type A and type B ET-1 receptors (ETA and ETB would ameliorate glucose intolerance and IR in mice exposed to IH. Subcutaneously implanted pumps delivered BQ-123 (ETA antagonist; 200 nmol/kg/day, BQ-788 (ETB antagonist; 200 nmol/kg/day or vehicle (saline or propyleneglycol [PG] for 14 days in C57BL6/J mice (10/group. During treatment, mice were exposed to IH (decreasing the FiO2 from 20.9% to 6%, 60/h or intermittent air (IA. After IH or IA exposure, insulin (0.5 IU/kg or glucose (1 mg/kg was injected intraperitoneally and plasma glucose determined after injection and area under glucose curve (AUC was calculated. Fourteen-day IH increased fasting glucose levels (122 ± 7 vs. 157 ± 8 mg/dL, PG: 118 ± 6 vs. 139 ± 8; both p < 0.05 and impaired glucose tolerance (AUCglucose: 19,249 ± 1105 vs. 29,124 ± 1444, PG AUCglucose: 18,066 ± 947 vs. 25,135 ± 797; both p < 0.05 in vehicle-treated animals. IH-induced impairments in glucose tolerance were partially ameliorated with BQ-788 treatment (AUCglucose: 21,969 ± 662; p < 0.05. Fourteen-day IH also induced IR (AUCglucose: 7185 ± 401 vs. 8699 ± 401; p < 0.05. Treatment with BQ-788 decreased IR under IA (AUCglucose: 5281 ± 401, p < 0.05 and reduced worsening of IR with IH (AUCglucose: 7302 ± 401, p < 0.05. There was no effect of BQ-123 on IH-induced impairments in glucose tolerance or IR. Our results suggest that ET-1 plays a role in IH-induced impairments in glucose homeostasis.

Differential effects of mineralocorticoid blockade on the hypothalamo-pituitary-adrenal axis in pregnant and nonpregnant ewes

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Lingis, Melissa; Richards, Elaine M.

2011-01-01

During pregnancy, plasma ACTH and cortisol are chronically increased; this appears to occur through a reset of hypothalamo-pituitary-adrenal (HPA) activity. We have hypothesized that differences in mineralocorticoid receptor activity in pregnancy may alter feedback inhibition of the HPA axis. We tested the effect of MR antagonism in pregnant and nonpregnant ewes infused for 4 h with saline or the MR antagonist canrenoate. Pregnancy significantly increased plasma ACTH, cortisol, angiotensin II, and aldosterone. Infusion of canrenoate increased plasma ACTH, cortisol, and aldosterone in both pregnant and nonpregnant ewes; however, the temporal pattern of these responses differed between these two reproductive states. In nonpregnant ewes, plasma ACTH and cortisol transiently increased at 1 h of infusion, whereas in pregnant ewes the levels gradually increased and were significantly elevated from 2 to 4 h of infusion. MR blockade increased plasma aldosterone from 2 to 4 h in the pregnant ewes but only at 4 h in the nonpregnant ewes. In both pregnant and nonpregnant ewes, the increase in plasma aldosterone was significantly related to the timing and magnitude of the increase in plasma potassium. The results indicate a differential effect of MR activity in pregnant and nonpregnant ewes and suggest that the slow changes in ACTH, cortisol, and aldosterone are likely to be related to blockade of MR effects in the kidney rather than to effects of MR blockade in hippocampus or hypothalamus. PMID:21205934

Kinetic properties of 'dual' orexin receptor antagonists at OX1R and OX2R orexin receptors.

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Gabrielle Elizabeth Callander

2013-12-01

Full Text Available Orexin receptor antagonists represent attractive targets for the development of drugs for the treatment of insomnia. Both efficacy and safety are crucial in clinical settings and thorough investigations of pharmacokinetics and pharmacodynamics can predict contributing factors such as duration of action and undesirable effects. To this end, we studied the interactions between various ‘dual’ orexin receptor antagonists and the orexin receptors, OX1R and OX2R, over time using saturation and competition radioligand binding with [3H]-BBAC ((S-N-([1,1'-biphenyl]-2-yl-1-(2-((1-methyl-1H-benzo[d]imidazol-2-ylthioacetylpyrrolidine-2-carboxamide. In addition, the kinetics of these compounds were investigated in cells expressing human, mouse and rat OX1R and OX2R using FLIPR® assays for calcium accumulation. We demonstrate that almorexant reaches equilibrium very slowly at OX2R, whereas SB-649868, suvorexant and filorexant may take hours to reach steady state at both orexin receptors. By contrast, compounds such as BBAC or the selective OX2R antagonist IPSU ((2-((1H-Indol-3-ylmethyl-9-(4-methoxypyrimidin-2-yl-2,9-diazaspiro[5.5]undecan-1-one bind rapidly and reach equilibrium very quickly in both binding and / or functional assays. Overall, the dual antagonists tested here tend to be rather unselective under non-equilibrium conditions and reach equilibrium very slowly. Once equilibrium is reached, each ligand demonstrates a selectivity profile that is however, distinct from the non-equilibrium condition. The slow kinetics of the dual antagonists tested suggest that in vitro receptor occupancy may be longer lasting than would be predicted. This raises questions as to whether pharmacokinetic studies measuring plasma or brain levels of these antagonists are accurate reflections of receptor occupancy in vivo.

The selective orexin receptor 1 antagonist ACT-335827 in a rat model of diet-induced obesity associated with metabolic syndrome

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Steiner, Michel A.; Sciarretta, Carla; Pasquali, Anne; Jenck, Francois

2013-01-01

The orexin system regulates feeding, nutrient metabolism and energy homeostasis. Acute pharmacological blockade of orexin receptor 1 (OXR-1) in rodents induces satiety and reduces normal and palatable food intake. Genetic OXR-1 deletion in mice improves hyperglycemia under high-fat (HF) diet conditions. Here we investigated the effects of chronic treatment with the novel selective OXR-1 antagonist ACT-335827 in a rat model of diet-induced obesity (DIO) associated with metabolic syndrome (MetS...

Early MEK1/2 Inhibition after Global Cerebral Ischemia in Rats Reduces Brain Damage and Improves Outcome by Preventing Delayed Vasoconstrictor Receptor Upregulation

DEFF Research Database (Denmark)

Johansson, Sara Ellinor; Larsen, Stine Schmidt; Povlsen, Gro Klitgaard

2014-01-01

BACKGROUND: Global cerebral ischemia following cardiac arrest is associated with increased cerebral vasoconstriction and decreased cerebral blood flow, contributing to delayed neuronal cell death and neurological detriments in affected patients. We hypothesize that upregulation of contractile ETB...... and 5-HT1B receptors, previously demonstrated in cerebral arteries after experimental global ischemia, are a key mechanism behind insufficient perfusion of the post-ischemic brain, proposing blockade of this receptor upregulation as a novel target for prevention of cerebral hypoperfusion and delayed...... neuronal cell death after global cerebral ischemia. The aim was to characterize the time-course of receptor upregulation and associated neuronal damage after global ischemia and investigate whether treatment with the MEK1/2 inhibitor U0126 can prevent cerebrovascular receptor upregulation and thereby...

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

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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...

[STUDYING THE ROLE OF BRAIN MELANOCORTIN RECEPTORS IN THE SUPPRESSING OF FOOD INTAKE UNDER ETHER STRESS IN MICE].

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Bazhan, N M; Kulikova, E V; Makarova, E N; Yakovleva, T V; Kazantseva, A Yu

2015-12-01

Melanocortin (MC) system regulates food intake under the rest conditions. Stress inhibits food intake. It is not clear whether brain MC system is involved in stress-induced anorexia in mice. The aim of the work was to investigate the effect of pharmacological blockade and activation of brain MC receptors on food intake under stress. C57B1/6J male mice were subjected to ether stress (0.5 minute ether anesthesia) before the administration of saline solution or synthetic non-selective blocker (SHU9119) or agonist (Melanotan II) of MC receptors into the lateral brain ventricle. Food intake was pre-stimulated with 17 hours of fasting in all mice. Ether stress decreased food intake, increased the plasma corticosterone level and hypothalamic mRNA AgRP (natural MC receptor antagonist) level at 1 hour after the stress. Pharmacological blockade of the MC receptors weakened stress-induced anorexia and decreased mRNA AgRP level in the hypothalamus. Pharmacological stimulation of the MC receptors enhanced ether stress-induced anorexia and hypercortisolism. Thus, our data demonstrated that the central MC system was involved in the development of stress-induced anorexia in mice.

Blocking mineralocorticoid receptors impairs, blocking glucocorticoid receptors enhances memory retrieval in humans.

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Rimmele, Ulrike; Besedovsky, Luciana; Lange, Tanja; Born, Jan

2013-04-01

Memory retrieval is impaired at very low as well as very high cortisol levels, but not at intermediate levels. This inverted-U-shaped relationship between cortisol levels and memory retrieval may originate from different roles of the mineralocorticoid (MR) and glucocorticoid receptor (GR) that bind cortisol with distinctly different affinity. Here, we examined the role of MRs and GRs in human memory retrieval using specific receptor antagonists. In two double-blind within-subject, cross-over designed studies, young healthy men were asked to retrieve emotional and neutral texts and pictures (learnt 3 days earlier) between 0745 and 0915 hours in the morning, either after administration of 400 mg of the MR blocker spironolactone vs placebo (200 mg at 2300 hours and 200 mg at 0400 hours, Study I) or after administration of the GR blocker mifepristone vs placebo (200 mg at 2300 hours, Study II). Blockade of MRs impaired free recall of both texts and pictures particularly for emotional material. In contrast, blockade of GRs resulted in better memory retrieval for pictures, with the effect being more pronounced for neutral than emotional materials. These findings indicate indeed opposing roles of MRs and GRs in memory retrieval, with optimal retrieval at intermediate cortisol levels likely mediated by high MR but concurrently low GR activation.

Sulpiride and the role of dopaminergic receptor blockade in the antipsychotic activity of neuroleptics

International Nuclear Information System (INIS)

Memo, M.; Battaini, F.; Spano, P.F.; Trabucchi, M.

1981-01-01

It is now generally recognized that dopamine receptors excist in the CNS as different subtypes: D 1 receptors, associated with adenylyl cyclase activity, and D 2 receptor, uncoupled to a cyclic APM generating system. In order to understand the role of D 1 and D 2 receptors in the antipsychotic action of neuroleptics, we have performed subchronic treatment with haloperidol, a drug which acts on D 1 receptors, and sulpiride, a selective antagonist to D 2 receptors. Long-term treatment with haloperidol does not induce significant supersensitivity of the D 2 receptors. In fact under these conditions 3 H-(-)-sulpiride binding, which is a marker of D 2 receptor function, does not increase in rat striatum, while the long-term administration of sulpiride, itself produces supersensitivity of D 2 receptors. Moreover, sulpiride does not induce supersensitivity of the D 1 receptors, characterized by 3 H-spiroperidol binding. These data suggest that both types of dopamine receptors may be involved in the clinical antipsychotic effects of neuroleptics. Unilateral leison of the nigrostriatal dopaminergic pathway produces an increase of striatal dopaminergic receptors, measured either by 3 H-spiroperidol and 3 H-(-)-sulpiride binding. These findings suggest that D 1 and D 2 receptors are present in postsynaptic membranes while it is still not known whether they exist in the same cellular elements. (author)

Amenorrhea secondary to a vismodegib-induced blockade of follicle-stimulating hormone-receptor activation.

Science.gov (United States)

Strasswimmer, John; Latimer, Benjamin; Ory, Steven

2014-08-01

To report a novel mechanism suggestive of early ovarian failure secondary to the anti-tumor hedgehog-pathway inhibitor vismodegib. Case report and literature review. Academic and private dermatology and fertility practices. A 34-year-old nulliparous woman with locally advanced basal cell carcinomas who became amenorrheic while receiving oral therapy with vismodegib. Physical examination and endocrine evaluation. Elevated follicle-stimulating hormone (FSH) and low estrogen in the setting of a normal anti-Müllerian hormone. FSH was elevated; estrogen was low. Preantral follicles were detected and anti-Müllerian hormone activity was normal. Menses resumed 5 weeks after cessation of therapy. Vismodegib, a first-in-class inhibitor of the hedgehog signaling pathway is indicated for advanced basal cell carcinoma and is associated with amenorrhea. The mechanism is unknown; it has some features of ovarian failure but preserves ovarian potential through blockading of FSH-receptor-dependent signal transduction. This effect appears to be rapidly reversible upon cessation of therapy. Vismodegib and related compounds may have potential for a role in intervention for gynecologic and endocrine disorders and in therapy for other issues involving FSH-dependent function. Copyright © 2014 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.

Progesterone receptor blockade in human breast cancer cells decreases cell cycle progression through G2/M by repressing G2/M genes.

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Clare, Susan E; Gupta, Akash; Choi, MiRan; Ranjan, Manish; Lee, Oukseub; Wang, Jun; Ivancic, David Z; Kim, J Julie; Khan, Seema A

2016-05-23

The synthesis of specific, potent progesterone antagonists adds potential agents to the breast cancer prevention and treatment armamentarium. The identification of individuals who will benefit from these agents will be a critical factor for their clinical success. We utilized telapristone acetate (TPA; CDB-4124) to understand the effects of progesterone receptor (PR) blockade on proliferation, apoptosis, promoter binding, cell cycle progression, and gene expression. We then identified a set of genes that overlap with human breast luteal-phase expressed genes and signify progesterone activity in both normal breast cells and breast cancer cell lines. TPA administration to T47D cells results in a 30 % decrease in cell number at 24 h, which is maintained over 72 h only in the presence of estradiol. Blockade of progesterone signaling by TPA for 24 h results in fewer cells in G2/M, attributable to decreased expression of genes that facilitate the G2/M transition. Gene expression data suggest that TPA affects several mechanisms that progesterone utilizes to control gene expression, including specific post-translational modifications, and nucleosomal organization and higher order chromatin structure, which regulate access of PR to its DNA binding sites. By comparing genes induced by the progestin R5020 in T47D cells with those increased in the luteal-phase normal breast, we have identified a set of genes that predict functional progesterone signaling in tissue. These data will facilitate an understanding of the ways in which drugs such as TPA may be utilized for the prevention, and possibly the therapy, of human breast cancer.

Combination approaches with immune checkpoint blockade in cancer therapy

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Maarten Swart

2016-11-01

Full Text Available In healthy individuals, immune checkpoint molecules prevent autoimmune responses and limit immune cell-mediated tissue damage. Tumors frequently exploit these molecules to evade eradication by the immune system. Over the past years, immune checkpoint blockade of cytotoxic T lymphocyte antigen-4 (CTLA-4 and programmed death-1 (PD-1 emerged as promising strategies to activate anti-tumor cytotoxic T cell responses. Although complete regression and long-term survival is achieved in some patients, not all patients respond. This review describes promising, novel combination approaches involving immune checkpoint blockade, aimed at increasing response-rates to the single treatments.

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

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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.

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

OpenAIRE

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

2015-01-01

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 Angiotensin Receptor Modulation in the Management of Cardio-Metabolic Disorders

DEFF Research Database (Denmark)

Paulis, Ludovit; Foulquier, Sébastien; Namsolleck, Pawel

2016-01-01

Cardiovascular and metabolic disorders, such as hypertension, insulin resistance, dyslipidemia or obesity are linked with chronic low-grade inflammation and dysregulation of the renin-angiotensin system (RAS). Consequently, RAS inhibition by ACE inhibitors or angiotensin AT1 receptor (AT1R...... blockade abolishes the AT1R-linked RAS almost completely with subsequent risk of hypotension and hypotension-related events, i.e. syncope or renal dysfunction. Such complications might be especially prominent in patients with renal impairment or patients with isolated systolic hypertension and normal...

Sulpiride and the role of dopaminergic receptor blockade in the antipsychotic activity of neuroleptics

Energy Technology Data Exchange (ETDEWEB)

Memo, M; Battaini, F; Spano, P F; Trabucchi, M [University of Brescia, (Italy). Dept. of Pharmacology

1981-01-01

It is now generally recognized that dopamine receptors excist in the CNS as different subtypes: D/sub 1/ receptors, associated with adenylyl cyclase activity, and D/sub 2/ receptor, uncoupled to a cyclic AMP generating system. In order to understand the role of D/sub 1/ and D/sub 2/ receptors in the antipsychotic action of neuroleptics, we have performed subchronic treatment with haloperidol, a drug which acts on D/sub 1/ receptors, and sulpiride, a selective antagonist to D/sub 2/ receptors. Long-term treatment with haloperidol does not induce significant supersensitivity of the D/sub 2/ receptors. In fact under these conditions /sup 3/H-(-)-sulpiride binding, which is a marker of D/sub 2/ receptor function, does not increase in rat striatum, while the long-term administration of sulpiride, itself produces supersensitivity of D/sub 2/ receptors. Moreover, sulpiride does not induce supersensitivity of the D/sub 1/ receptors, characterized by /sup 3/H-spiroperidol binding. These data suggest that both types of dopamine receptors may be involved in the clinical antipsychotic effects of neuroleptics. Unilateral leison of the nigrostriatal dopaminergic pathway produces an increase of striatal dopaminergic receptors, measured either by /sup 3/H-spiroperidol and /sup 3/H-(-)-sulpiride binding. These findings suggest that D/sub 1/ and D/sub 2/ receptors are present in postsynaptic membranes while it is still not known whether they exist in the same cellular elements.

Selective activation of estrogen receptors, ERα and GPER-1, rapidly decreases food intake in female rats.

Science.gov (United States)

Butler, Michael J; Hildebrandt, Ryan P; Eckel, Lisa A

2018-05-25

Many of estradiol's behavioral effects are mediated, at least partially, via extra-nuclear estradiol signaling. Here, we investigated whether two estrogen receptor (ER) agonists, targeting ERα and G protein-coupled ER-1 (GPER-1), can promote rapid anorexigenic effects. Food intake was measured in ovariectomized (OVX) rats at 1, 2, 4, and 22 h following subcutaneous (s.c.) injection of an ERα agonist (PPT; 0-200 μg/kg), a GPER-1 agonist (G-1; 0-1600 μg/kg), and a GPER-1 antagonist (G-36; 0-80 μg/kg). To investigate possible cross-talk between ERα and GPER-1, we examined whether GPER-1 blockade affects the anorexigenic effect of PPT. Feeding was monitored in OVX rats that received s.c. injections of vehicle or 40 μg/kg G-36 followed 30 min later by s.c. injections of vehicle or 200 μg/kg PPT. Selective activation of ERα and GPER-1 alone decreased food intake within 1 h of drug treatment, and feeding remained suppressed for 22 h following PPT treatment and 4 h following G-1 treatment. Acute administration of G-36 alone did not suppress feeding at any time point. Blockade of GPER-1 attenuated PPT's rapid (within 1 h) anorexigenic effect, but did not modulate PPT's ability to suppress food intake at 2, 4 and 22 h. These findings demonstrate that selective activation of ERα produces a rapid (within 1 h) decrease in food intake that is best explained by a non-genomic signaling pathway and thus implicates the involvement of extra-nuclear ERα. Our findings also provide evidence that activation of GPER-1 is both sufficient to suppress feeding and necessary for PPT's rapid anorexigenic effect. Copyright © 2017. Published by Elsevier Inc.

Localized CD47 blockade enhances immunotherapy for murine melanoma.

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Ingram, Jessica R; Blomberg, Olga S; Sockolosky, Jonathan T; Ali, Lestat; Schmidt, Florian I; Pishesha, Novalia; Espinosa, Camilo; Dougan, Stephanie K; Garcia, K Christopher; Ploegh, Hidde L; Dougan, Michael

2017-09-19

CD47 is an antiphagocytic ligand broadly expressed on normal and malignant tissues that delivers an inhibitory signal through the receptor signal regulatory protein alpha (SIRPα). Inhibitors of the CD47-SIRPα interaction improve antitumor antibody responses by enhancing antibody-dependent cellular phagocytosis (ADCP) in xenograft models. Endogenous expression of CD47 on a variety of cell types, including erythrocytes, creates a formidable antigen sink that may limit the efficacy of CD47-targeting therapies. We generated a nanobody, A4, that blocks the CD47-SIRPα interaction. A4 synergizes with anti-PD-L1, but not anti-CTLA4, therapy in the syngeneic B16F10 melanoma model. Neither increased dosing nor half-life extension by fusion of A4 to IgG2a Fc (A4Fc) overcame the issue of an antigen sink or, in the case of A4Fc, systemic toxicity. Generation of a B16F10 cell line that secretes the A4 nanobody showed that an enhanced response to several immune therapies requires near-complete blockade of CD47 in the tumor microenvironment. Thus, strategies to localize CD47 blockade to tumors may be particularly valuable for immune therapy.

Cerebral A{sub 1} adenosine receptors (A{sub 1}AR) in liver cirrhosis

Energy Technology Data Exchange (ETDEWEB)

Boy, Christian [Research Centre Juelich, Brain Imaging Centre West, Institute of Medicine, Juelich (Germany); University Hospital Essen, Department of Nuclear Medicine, Essen (Germany); Meyer, Philipp T. [Research Centre Juelich, Brain Imaging Centre West, Institute of Medicine, Juelich (Germany); University Hospital Aachen, Department of Nuclear Medicine, Aachen (Germany); Kircheis, Gerald; Haussinger, Dieter [University of Duesseldorf, Clinic for Gastroenterology, Hepatology and Infectiology, Duesseldorf (Germany); Holschbach, Marcus H.; Coenen, Heinz H. [Research Centre Juelich, Institute of Nuclear Chemistry, Juelich (Germany); Herzog, Hans; Elmenhorst, David [Research Centre Juelich, Brain Imaging Centre West, Institute of Medicine, Juelich (Germany); Kaiser, Hans J. [University Hospital Aachen, Department of Nuclear Medicine, Aachen (Germany); Zilles, Karl [Research Centre Juelich, Brain Imaging Centre West, Institute of Medicine, Juelich (Germany); C. and O. Vogt Institute of Brain Research, Duesseldorf (Germany); Bauer, Andreas [Research Centre Juelich, Brain Imaging Centre West, Institute of Medicine, Juelich (Germany); University of Duesseldorf, Department of Neurology, Duesseldorf (Germany)

2008-03-15

The cerebral mechanisms underlying hepatic encephalopathy (HE) are poorly understood. Adenosine, a neuromodulator that pre- and postsynaptically modulates neuronal excitability and release of classical neurotransmitters via A{sub 1} adenosine receptors (A{sub 1}AR), is likely to be involved. The present study investigates changes of cerebral A{sub 1}AR binding in cirrhotic patients by means of positron emission tomography (PET) and [{sup 18}F]CPFPX, a novel selective A{sub 1}AR antagonist. PET was performed in cirrhotic patients (n = 10) and healthy volunteers (n = 10). Quantification of in vivo receptor density was done by Logan's non-invasive graphical analysis (pons as reference region). The outcome parameter was the apparent binding potential (aBP, proportional to B{sub max}/K{sub D}). Cortical and subcortical regions showed lower A{sub 1}AR binding in cirrhotic patients than in controls. The aBP changes reached statistical significance vs healthy controls (p < 0.05, U test with Bonferroni-Holm adjustment for multiple comparisons) in cingulate cortex (-50.0%), precentral gyrus (-40.9%), postcentral gyrus (-38.6%), insular cortex (-38.6%), thalamus (-32.9%), parietal cortex (-31.7%), frontal cortex (-28.6), lateral temporal cortex (-28.2%), orbitofrontal cortex (-27.9%), occipital cortex (-24.6), putamen (-22.7%) and mesial temporal lobe (-22.4%). Regional cerebral adenosinergic neuromodulation is heterogeneously altered in cirrhotic patients. The decrease of cerebral A{sub 1}AR binding may further aggravate neurotransmitter imbalance at the synaptic cleft in cirrhosis and hepatic encephalopathy. Different pathomechanisms may account for these alterations including decrease of A{sub 1}AR density or affinity, as well as blockade of the A{sub 1}AR by endogenous adenosine or exogenous xanthines. (orig.)

Enhanced expressions of microvascular smooth muscle receptors after focal cerebral ischemia occur via the MAPK MEK/ERK pathway

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Edvinsson Lars

2008-09-01

Full Text Available Abstract Background MEK1/2 is a serine/threonine protein that phosphorylates extracellular signal-regulated kinase (ERK1/2. Cerebral ischemia results in enhanced expression of cerebrovascular contractile receptors in the middle cerebral artery (MCA leading to the ischemic region. Here we explored the role of the MEK/ERK pathway in receptor expression following ischemic brain injury using the specific MEK1 inhibitor U0126. Methods and result Rats were subjected to a 2-h middle cerebral artery occlusion (MCAO followed by reperfusion for 48-h and the ischemic area was calculated. The expression of phosphorylated ERK1/2 and Elk-1, and of endothelin ETA and ETB, angiotensin AT1, and 5-hydroxytryptamine 5-HT1B receptors were analyzed with immunohistochemistry using confocal microscopy in cerebral arteries, microvessels and in brain tissue. The expression of endothelin ETB receptor was analyzed by quantitative Western blot. We demonstrate that there is an increase in the number of contractile smooth muscle receptors in the MCA and in micro- vessels within the ischemic region. The enhanced expression occurs in the smooth muscle cells as verified by co-localization studies. This receptor upregulation is furthermore associated with enhanced expression of pERK1/2 and of transcription factor pElk-1 in the vascular smooth muscle cells. Blockade of transcription with the MEK1 inhibitor U0126, given at the onset of reperfusion or as late as 6 hours after the insult, reduced transcription (pERK1/2 and pElk-1, the enhanced vascular receptor expression, and attenuated the cerebral infarct and improved neurology score. Conclusion Our results show that MCAO results in upregulation of cerebrovascular ETB, AT1 and 5-HT1B receptors. Blockade of this event with a MEK1 inhibitor as late as 6 h after the insult reduced the enhanced vascular receptor expression and the associated cerebral infarction.

PD-1/PD-L blockade in gastrointestinal cancers: lessons learned and the road toward precision immunotherapy

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Junyu Long

2017-08-01

Full Text Available Abstract Gastrointestinal (GI malignancies are the most prevalent tumors worldwide, with increasing incidence and mortality. Although surgical resection, chemotherapy, radiotherapy, and molecular targeted therapy have led to significant advances in the treatment of GI cancer patients, overall survival is still low. Therefore, alternative strategies must be identified to improve patient outcomes. In the tumor microenvironment, tumor cells can escape the host immune response through the interaction of PD-1 and PD-L, which inhibits the function of T cells and tumor-infiltrating lymphocytes while increasing the function of immunosuppressive T regulatory cells. The use of an anti-PD-1/PD-L blockade enables reprogramming of the immune system to efficiently identify and kill tumor cells. In recent years, the efficacy of PD-1/PD-L blockade has been demonstrated in many tumors, and this treatment is expected to be a pan-immunotherapy for tumors. Here, we review the signaling pathway underlying the dysregulation of PD-1/PD-L in tumors, summarize the current clinical data for PD-1/PD-L inhibitors in GI malignancies, and discuss road toward precision immunotherapy in relation to PD-1/PD-L blockade. The preliminary data for PD-1/PD-L inhibitors are encouraging, and the precision immunotherapy of PD-1/PD-L inhibitors will be a viable and pivotal clinical strategy for GI cancer therapy.

PD-1/PD-L blockade in gastrointestinal cancers: lessons learned and the road toward precision immunotherapy.

Science.gov (United States)

Long, Junyu; Lin, Jianzhen; Wang, Anqiang; Wu, Liangcai; Zheng, Yongchang; Yang, Xiaobo; Wan, Xueshuai; Xu, Haifeng; Chen, Shuguang; Zhao, Haitao

2017-08-03

Gastrointestinal (GI) malignancies are the most prevalent tumors worldwide, with increasing incidence and mortality. Although surgical resection, chemotherapy, radiotherapy, and molecular targeted therapy have led to significant advances in the treatment of GI cancer patients, overall survival is still low. Therefore, alternative strategies must be identified to improve patient outcomes. In the tumor microenvironment, tumor cells can escape the host immune response through the interaction of PD-1 and PD-L, which inhibits the function of T cells and tumor-infiltrating lymphocytes while increasing the function of immunosuppressive T regulatory cells. The use of an anti-PD-1/PD-L blockade enables reprogramming of the immune system to efficiently identify and kill tumor cells. In recent years, the efficacy of PD-1/PD-L blockade has been demonstrated in many tumors, and this treatment is expected to be a pan-immunotherapy for tumors. Here, we review the signaling pathway underlying the dysregulation of PD-1/PD-L in tumors, summarize the current clinical data for PD-1/PD-L inhibitors in GI malignancies, and discuss road toward precision immunotherapy in relation to PD-1/PD-L blockade. The preliminary data for PD-1/PD-L inhibitors are encouraging, and the precision immunotherapy of PD-1/PD-L inhibitors will be a viable and pivotal clinical strategy for GI cancer therapy.

Proximal Tubular Cannabinoid-1 Receptor Regulates Obesity-Induced CKD.

Science.gov (United States)

Udi, Shiran; Hinden, Liad; Earley, Brian; Drori, Adi; Reuveni, Noa; Hadar, Rivka; Cinar, Resat; Nemirovski, Alina; Tam, Joseph

2017-12-01

Obesity-related structural and functional changes in the kidney develop early in the course of obesity and occur independently of hypertension, diabetes, and dyslipidemia. Activating the renal cannabinoid-1 receptor (CB 1 R) induces nephropathy, whereas CB 1 R blockade improves kidney function. Whether these effects are mediated via a specific cell type within the kidney remains unknown. Here, we show that specific deletion of CB 1 R in the renal proximal tubule cells did not protect the mice from obesity, but markedly attenuated the obesity-induced lipid accumulation in the kidney and renal dysfunction, injury, inflammation, and fibrosis. These effects associated with increased activation of liver kinase B1 and the energy sensor AMP-activated protein kinase, as well as enhanced fatty acid β -oxidation. Collectively, these findings indicate that renal proximal tubule cell CB 1 R contributes to the pathogenesis of obesity-induced renal lipotoxicity and nephropathy by regulating the liver kinase B1/AMP-activated protein kinase signaling pathway. Copyright © 2017 by the American Society of Nephrology.

Interaction of antibiotics on pipecuronium-induced neuromuscular blockade.

Science.gov (United States)

de Gouw, N E; Crul, J F; Vandermeersch, E; Mulier, J P; van Egmond, J; Van Aken, H

1993-01-01

To measure the interaction of two antibiotics (clindamycin and colistin) on neuromuscular blockade induced by pipecuronium bromide (a new long-acting, steroidal, nondepolarizing neuromuscular blocking drug). Prospective, randomized, placebo-controlled study. Inpatient gynecologic and gastroenterologic service at a university medical center. Three groups of 20 ASA physical status I and II patients with normal kidney and liver function, taking no medication, and undergoing elective surgery under general anesthesia. Anesthesia was induced with propofol and alfentanil intravenously (IV) and maintained with a propofol infusion and 60% nitrous oxide in oxygen. Pipecuronium bromide 50 micrograms/kg was administered after reaching a stable baseline of single-twitch response. At 25% recovery of pipecuronium-induced neuromuscular blockade, patients received one of two antibiotics, clindamycin 300 mg or colistin 1 million IU, or a placebo. The recovery index (RI, defined as time from 25% to 75% recovery of neuromuscular blockade) was measured using the single-twitch response of the adductor pollicis muscle with supramaximal stimulation of the ulnar nerve at the wrist. RI after administration of an antibiotic (given at 25% recovery) was measured and compared with RI of the control group using Student's unpaired t-test. Statistical analyses of the results showed a significant prolongation of the recovery time (from 25% to 75% recovery) of 40 minutes for colistin. When this type of antibiotic is used during anesthesia with pipercuronium as a muscle relaxant, one must be aware of a significant prolongation of an already long-acting neuromuscular blockade and (although not observed in this study) possible problems in antagonism.

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

International Nuclear Information System (INIS)

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

1991-01-01

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

Myostatin deficiency but not anti-myostatin blockade induces marked proteomic changes in mouse skeletal muscle.

Science.gov (United States)

Salzler, Robert R; Shah, Darshit; Doré, Anthony; Bauerlein, Roy; Miloscio, Lawrence; Latres, Esther; Papadopoulos, Nicholas J; Olson, William C; MacDonald, Douglas; Duan, Xunbao

2016-07-01

Pharmacologic blockade of the myostatin (Mstn)/activin receptor pathway is being pursued as a potential therapy for several muscle wasting disorders. The functional benefits of blocking this pathway are under investigation, in particular given the findings that greater muscle hypertrophy results from Mstn deficiency arising from genetic ablation compared to post-developmental Mstn blockade. Using high-resolution MS coupled with SILAC mouse technology, we quantitated the relative proteomic changes in gastrocnemius muscle from Mstn knockout (Mstn(-/-) ) and mice treated for 2-weeks with REGN1033, an anti-Mstn antibody. Relative to wild-type animals, Mstn(-/-) mice had a two-fold greater muscle mass and a >1.5-fold change in expression of 12.0% of 1137 quantified muscle proteins. In contrast, mice treated with REGN1033 had minimal changes in muscle proteome (0.7% of 1510 proteins >1.5-fold change, similar to biological difference 0.5% of 1310) even though the treatment induced significant 20% muscle mass increase. Functional annotation of the altered proteins in Mstn(-/-) mice corroborates the mutiple physiological changes including slow-to-fast fiber type switch. Thus, the proteome-wide protein expression differs between Mstn(-/-) mice and mice subjected to specific Mstn blockade post-developmentally, providing molecular-level insights to inform mechanistic hypotheses to explain the observed functional differences. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Influence of beta blockade on gastric acid secretion and changes in gastric mucosal blood flow before and after parietal cell vagotomy in dogs and man

DEFF Research Database (Denmark)

Hovendal, C P; Bech, K; Bekker, C

1983-01-01

The aim of the present study was, in paired experiments in dogs, to examine the effect of beta-receptor blockade on gastric acid secretion and mucosal blood flow before and after parietal cell vagotomy (PCV). The secretory response to pentagastrin was reduced after vagotomy. beta-Adrenergic block......The aim of the present study was, in paired experiments in dogs, to examine the effect of beta-receptor blockade on gastric acid secretion and mucosal blood flow before and after parietal cell vagotomy (PCV). The secretory response to pentagastrin was reduced after vagotomy. beta...

The adenosine A2A antagonist MSX-3 reverses the effort-related effects of dopamine blockade: differential interaction with D1 and D2 family antagonists.

Science.gov (United States)

Worden, Lila T; Shahriari, Mona; Farrar, Andrew M; Sink, Kelly S; Hockemeyer, Jörg; Müller, Christa E; Salamone, John D

2009-04-01

Brain dopamine (DA) participates in the modulation of instrumental behavior, including aspects of behavioral activation and effort-related choice behavior. Rats with impaired DA transmission reallocate their behavior away from food-seeking behaviors that have high response requirements, and instead select less effortful alternatives. Although accumbens DA is considered a critical component of the brain circuitry regulating effort-related choice behavior, emerging evidence demonstrates a role for adenosine A(2A) receptors. Adenosine A(2A) receptor antagonism has been shown to reverse the effects of DA antagonism. The present experiments were conducted to determine if this effect was dependent upon the subtype of DA receptor that was antagonized to produce the changes in effort-related choice. The adenosine A(2A) receptor antagonist MSX-3 (0.5-2.0 mg/kg IP) was assessed for its ability to reverse the effects of the D1 family antagonist SCH39166 (ecopipam; 0.2 mg/kg IP) and the D2 family antagonist eticlopride (0.08 mg/kg IP), using a concurrent lever pressing/chow feeding procedure. MSX-3 produced a substantial dose-related reversal of the effects of eticlopride on lever pressing and chow intake. At the highest dose of MSX-3, there was a complete reversal of the effects of eticlopride on lever pressing. In contrast, MSX-3 produced only a minimal attenuation of the effects of SCH39166, as measured by regression and effect size analyses. The greater ability of MSX-3 to reverse the effects of D2 vs. D1 blockade may be related to the colocalization of D2 and adenosine A(2A) receptors on the same population of striatal neurons.

Blockade of Death Ligand TRAIL Inhibits Renal Ischemia Reperfusion Injury

International Nuclear Information System (INIS)

Adachi, Takaomi; Sugiyama, Noriyuki; Gondai, Tatsuro; Yagita, Hideo; Yokoyama, Takahiko

2013-01-01

Renal ischemia-reperfusion injury (IRI) is a leading cause of acute kidney injury (AKI). Many investigators have reported that cell death via apoptosis significantly contributed to the pathophysiology of renal IRI. Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is a member of the tumor necrosis factor superfamily, and induces apoptosis and inflammation. However, the role of TRAIL in renal IRI is unclear. Here, we investigated whether TRAIL contributes to renal IRI and whether TRAIL blockade could attenuate renal IRI. AKI was induced by unilateral clamping of the renal pedicle for 60 min in male FVB/N mice. We found that the expression of TRAIL and its receptors were highly upregulated in renal tubular cells in renal IRI. Neutralizing anti-TRAIL antibody or its control IgG was given 24 hr before ischemia and a half-dose booster injection was administered into the peritoneal cavity immediately after reperfusion. We found that TRAIL blockade inhibited tubular apoptosis and reduced the accumulation of neutrophils and macrophages. Furthermore, TRAIL blockade attenuated renal fibrosis and atrophy after IRI. In conclusion, our study suggests that TRAIL is a critical pathogenic factor in renal IRI, and that TRAIL could be a new therapeutic target for the prevention of renal IRI

The cannabinoid CB1 receptor and mTORC1 signalling pathways interact to modulate glucose homeostasis in mice

Directory of Open Access Journals (Sweden)

Francisco J. Bermudez-Silva

2016-01-01

Full Text Available The endocannabinoid system (ECS is an intercellular signalling mechanism that is present in the islets of Langerhans and plays a role in the modulation of insulin secretion and expansion of the β-cell mass. The downstream signalling pathways mediating these effects are poorly understood. Mammalian target of rapamycin complex 1 (mTORC1 signalling is a key intracellular pathway involved in energy homeostasis and is known to importantly affect the physiology of pancreatic islets. We investigated the possible relationship between cannabinoid type 1 (CB1 receptor signalling and the mTORC1 pathway in the endocrine pancreas of mice by using pharmacological analysis as well as mice genetically lacking the CB1 receptor or the downstream target of mTORC1, the kinase p70S6K1. In vitro static secretion experiments on islets, western blotting, and in vivo glucose and insulin tolerance tests were performed. The CB1 receptor antagonist rimonabant decreased glucose-stimulated insulin secretion (GSIS at 0.1 µM while increasing phosphorylation of p70S6K1 and ribosomal protein S6 (rpS6 within the islets. Specific pharmacological blockade of mTORC1 by 3 nM rapamycin, as well as genetic deletion of p70S6K1, impaired the CB1-antagonist-mediated decrease in GSIS. In vivo experiments showed that 3 mg/kg body weight rimonabant decreased insulin levels and induced glucose intolerance in lean mice without altering peripheral insulin sensitivity; this effect was prevented by peripheral administration of low doses of rapamycin (0.1 mg/kg body weight, which increased insulin sensitivity. These findings suggest a functional interaction between the ECS and the mTORC1 pathway within the endocrine pancreas and at the whole-organism level, which could have implications for the development of new therapeutic approaches for pancreatic β-cell diseases.

Enhanced expressions of microvascular smooth muscle receptors after focal cerebral ischemia occur via the MAPK MEK/ERK pathway

DEFF Research Database (Denmark)

Maddahi, A.; Edvinsson, L.

2008-01-01

), the enhanced vascular receptor expression, and attenuated the cerebral infarct and improved neurology score. CONCLUSION: Our results show that MCAO results in upregulation of cerebrovascular ETB, AT1 and 5-HT1B receptors. Blockade of this event with a MEK1 inhibitor as late as 6 h after the insult reduced...... the role of the MEK/ERK pathway in receptor expression following ischemic brain injury using the specific MEK1 inhibitor U0126. METHODS AND RESULT: Rats were subjected to a 2-h middle cerebral artery occlusion (MCAO) followed by reperfusion for 48-h and the ischemic area was calculated. The expression...... of phosphorylated ERK1/2 and Elk-1, and of endothelin ETA and ETB, angiotensin AT1, and 5-hydroxytryptamine 5-HT1B receptors were analyzed with immunohistochemistry using confocal microscopy in cerebral arteries, microvessels and in brain tissue. The expression of endothelin ETB receptor was analyzed...

mGluR1 receptors contribute to non-purinergic slow excitatory transmission to submucosal VIP neurons of guinea-pig ileum

Directory of Open Access Journals (Sweden)

Jaime Pei Pei Foong

2009-05-01

Full Text Available Vasoactive intestinal peptide (VIP immunoreactive secretomotor neurons in the submucous plexus are involved in mediating bacterial toxin-induced hypersecretion leading to diarrhoea. VIP neurons become hyperexcitable after the mucosa is exposed to cholera toxin, which suggests that the manipulation of the excitability of these neurons may be therapeutic. This study used standard intracellular recording methods to systematically characterize slow excitatory postsynaptic potentials (EPSPs evoked in submucosal VIP neurons by different stimulus regimes (1, 3 and 15 pulse 30 Hz stimulation, together with their associated input resistances and pharmacology. All slow EPSPs were associated with a significant increase in input resistance compared to baseline values. Slow EPSPs evoked by a single stimulus were confirmed to be purinergic, however, slow EPSPs evoked by 15 pulse trains were non-purinergic and those evoked by 3 pulse trains were mixed. NK1 or NK3 receptor antagonists did not affect slow EPSPs. The group I mGluR receptor antagonist, PHCCC reduced the amplitude of purinergic and non-purinergic slow EPSPs. Blocking mGluR1 receptors depressed the overall response to 3 and 15 pulse trains, but this effect was inconsistent, while blockade of mGluR5 receptors had no effect on the non-purinergic slow EPSPs. Thus, although other receptors are almost certainly involved, our data indicate that there are at least two pharmacologically distinct types of slow EPSPs in the VIP secretomotor neurons: one mediated by P2Y receptors and the other in part by mGluR1 receptors.

Endogenous opioid peptide-mediated neurotransmission in central and pericentral nuclei of the inferior colliculus recruits μ1-opioid receptor to modulate post-ictal antinociception.

Science.gov (United States)

Felippotti, Tatiana Tocchini; de Freitas, Renato Leonardo; Coimbra, Norberto Cysne

2012-02-01

The aim of the present work was to investigate the involvement of the μ1-endogenous opioid peptide receptor-mediated system in post-ictal antinociception. Antinociceptive responses were determined by the tail-flick test after pre-treatment with the selective μ1-opioid receptor antagonist naloxonazine, peripherally or centrally administered at different doses. Peripheral subchronic (24 h) pre-treatment with naloxonazine antagonised the antinociception elicited by tonic-clonic seizures. Acute (10 min) pre-treatment, however, did not have the same effect. In addition, microinjections of naloxonazine into the central, dorsal cortical and external cortical nuclei of the inferior colliculus antagonised tonic-clonic seizure-induced antinociception. Neither acute (10-min) peripheral pre-treatment with naloxonazine nor subchronic intramesencephalic blockade of μ1-opioid receptors resulted in consistent statistically significant differences in the severity of tonic-clonic seizures shown by Racine's index (1972), although the intracollicular specific antagonism of μ1-opioid receptor decreased the duration of seizures. μ1-Opioid receptors and the inferior colliculus have been implicated in several endogenous opioid peptide-mediated responses such as antinociception and convulsion. The present findings suggest the involvement of μ1-opiate receptors of central and pericentral nuclei of the inferior colliculus in the modulation of tonic-clonic seizures and in the organisation of post-ictal antinociception. Copyright © 2011 Elsevier Ltd. All rights reserved.

N-cadherin and integrin blockade inhibit arteriolar myogenic reactivity but not pressure-induced increases in intracellular Ca2+

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Teresa Y. Jackson

2010-12-01

Full Text Available The vascular myogenic response is characterized by arterial constriction in response to an increase in intraluminal pressure and dilatation to a decrease in pressure. This mechanism is important for the regulation of blood flow, capillary pressure and arterial pressure. The identity of the mechanosensory mechanism(s for this response is incompletely understood but has been shown to include the integrins as cell-extracellular matrix receptors. The possibility that a cell-cell adhesion receptor is involved has not been studied. Thus, we tested the hypothesis that N-cadherin, a cell-cell adhesion molecule in vascular smooth muscle cells (VSMCs, was important for myogenic responsiveness. The purpose of this study was to investigate:
1. whether cadherin inhibition blocks myogenic responses to increases in intraluminal pressure and 2. the effect of the cadherin or integrin blockade on pressure-induced changes in [Ca2+]i. Cadherin blockade was tested in isolated rat cremaster arterioles on myogenic responses to acute pressure steps from 60 – 100 mmHg and changes in VSMC Ca2+ were measured using fura-2. In the presence of a synthetic cadherin inhibitory peptide or a function blocking antibody, myogenic responses were inhibited. In contrast, during N-cadherin blockade, pressure-induced changes in [Ca2+]i were not altered. Similarly, vessels treated with function-blocking β1- or β3-integrin antibodies maintained pressure-induced [Ca2+]i responses despite inhibition of myogenic constriction. Collectively, these data suggest that both cadherins and integrins play a fundamental role in mediating myogenic constriction but argue against their direct involvement in mediating pressure-induced [Ca2+]i increases.

Combination of behaviorally sub-effective doses of glutamate NMDA and dopamine D1 receptor antagonists impairs executive function.

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Desai, Sagar J; Allman, Brian L; Rajakumar, Nagalingam

2017-04-14

Impairment of executive function is a core feature of schizophrenia. Preclinical studies indicate that injections of either N-methyl d-aspartate (NMDA) or dopamine D 1 receptor blockers impair executive function. Despite the prevailing notion based on postmortem findings in schizophrenia that cortical areas have marked suppression of glutamate and dopamine, recent in vivo imaging studies suggest that abnormalities of these neurotransmitters in living patients may be quite subtle. Thus, we hypothesized that modest impairments in both glutamate and dopamine function can act synergistically to cause executive dysfunction. In the present study, we investigated the effect of combined administration of "behaviorally sub-effective" doses of NMDA and dopamine D 1 receptor antagonists on executive function. An operant conditioning-based set-shifting task was used to assess behavioral flexibility in rats that were systemically injected with NMDA and dopamine D 1 receptor antagonists individually or in combination prior to task performance. Separate injections of the NMDA receptor antagonist, MK-801, and the dopamine D 1 receptor antagonist, SCH 23390, at low doses did not impair set-shifting; however, the combined administration of these same behaviorally sub-effective doses of the antagonists significantly impaired the performance during set-shifting without affecting learning, retrieval of the memory of the initial rule, latency of responses or the number of omissions. The combined treatment also produced an increased number of perseverative errors. Our results indicate that NMDA and D 1 receptor blockade act synergistically to cause behavioral inflexibility, and as such, subtle abnormalities in glutamatergic and dopaminergic systems may act cooperatively to cause deficits in executive function. Copyright © 2017 Elsevier B.V. All rights reserved.

Effects of dopamine D1 receptor blockade in the prelimbic prefrontal cortex or lateral dorsal striatum on frontostriatal function in Wistar and Spontaneously Hypertensive Rats.

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Gauthier, Jamie M; Tassin, David H; Dwoskin, Linda P; Kantak, Kathleen M

2014-07-15

Attention Deficit Hyperactivity Disorder (ADHD) is associated with dysfunctional prefrontal and striatal circuitry and dysregulated dopamine neurotransmission. Spontaneously Hypertensive Rats (SHR), a heuristically useful animal model of ADHD, were evaluated against normotensive Wistar (WIS) controls to determine whether dopamine D1 receptor blockade of either prelimbic prefrontal cortex (plPFC) or lateral dorsal striatum (lDST) altered learning functions of both interconnected sites. A strategy set shifting task measured plPFC function (behavioral flexibility/executive function) and a reward devaluation task measured lDST function (habitual responding). Prior to tests, rats received bilateral infusions of SCH 23390 (1.0 μg/side) or vehicle into plPFC or lDST. Following vehicle, SHR exhibited longer lever press reaction times, more trial omissions, and fewer completed trials during the set shift test compared to WIS, indicating slower decision-making and attentional/motivational impairment in SHR. After reward devaluation, vehicle-treated SHR responded less than WIS, indicating relatively less habitual responding in SHR. After SCH 23390 infusions into plPFC, WIS expressed the same behavioral phenotype as vehicle-treated SHR during set shift and reward devaluation tests. In SHR, SCH 23390 infusions into plPFC exacerbated behavioral deficits in the set shift test and maintained the lower rate of responding in the reward devaluation test. SCH 23390 infusions into lDST did not modify set shifting in either strain, but produced lower rates of responding than vehicle infusions after reward devaluation in WIS. This research provides pharmacological evidence for unidirectional interactions between prefrontal and striatal brain regions, which has implications for the neurological basis of ADHD and its treatment. Copyright © 2014 Elsevier B.V. All rights reserved.

Reversible exacerbation of obstructive sleep apnea by α1-adrenergic blockade with tamsulosin: A case report.

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Moran, Mark

2016-01-01

Obstructive sleep apnea (OSA) is characterized by repeated involuntary closure of the pharyngeal airspace during sleep. Normal activity of the genioglossus (GG) muscle is important in maintaining airway patency, and inhibition of GG activity can contribute to airway closure. Neurons in the hypoglossal motor nucleus (HMN) regulate GG activity. Adrenergic tone is an important regulator of HMN neuronal excitability. In laboratory models α 1 -adrenergic antagonists inhibit HMN neurons and GG activity, suggesting that α 1 -adrenergic antagonism might adversely affect patients with OSA. To date there has been no report of such a case. The patient was a 67-year old man with a 27-month history of obstructive sleep apnea. Diagnostic polysomnography demonstrated a baseline apnea-hypopnea index (AHI) of 21.3 and a trough oxygen saturation of 84%. Treatment with continuous positive airway pressure (CPAP) was initiated. The AHI in year 1 averaged 1.0 ± 0.1 (mean ± SD) and 0.8 ± 0.1 in year 2. Other medical conditions included hypertension controlled with losartan and benign prostatic hypertrophy not well controlled by finasteride monotherapy. The α 1 -adrenergic receptor antagonist tamsulosin 0.4 mg daily was added. Shortly after initiation of tamsulosin, subjective sleep quality deteriorated. Significant surges in obstructive events, apneic episodes, and AHI were also recorded, and nocturnal airway pressure was frequently sustained at the CPAP device maximum of 20 cm H 2 O. Tamsulosin was discontinued. CPAP parameters and sleep quality returned to the pre-tamsulosin baselines within 10 days. These findings suggest that α 1 -adrenergic blockade with tamsulosin may exacerbate sleep-disordered breathing in susceptible patients.

Renin-angiotensin system (RAS) blockade attenuates growth and metastatic potential of renal cell carcinoma in mice.

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Araújo, Wedson F; Naves, Marcelo A; Ravanini, Juliana N; Schor, Nestor; Teixeira, Vicente P C

2015-09-01

Renal cell carcinoma (RCC) is the most frequent type of cancer among renal neoplasms in adults and responds poorly to radiotherapy and chemotherapy. There is evidence that blockade of the renin-angiotensin system (RAS) might have antineoplastic effects. The aim of this study was to investigate the effects of RAS blockade on RCC in a murine model. Murine renal cancer cells (Renca) were injected (1 × 10(5)) into the subcapsular space of the left kidney of BALB/c mice (8 wk of age). The animals were divided into 4 groups: a control group (no treatment), angiotensin-receptor blockers group (losartan 100mg/kg/d), angiotensin-converting enzyme inhibitor group (captopril 10mg/kg/d), and angiotensin-receptor blockers +angiotensin-converting enzyme inhibitor group (losartan 100mg/kg/d +captopril 10mg/kg/d). The animals received the drugs by gavage for 21 days after inoculation, beginning 2 days before tumor induction, and were then euthanized. After killing the animals, the kidneys and lungs were removed, weighed, and processed for histopathological and immunohistochemical analyses. Angiogenesis and vascular microvessels were assessed with the antibodies anti-vascular endothelial growth factor and anti-CD34. Angiotensin II-inoculated animals developed renal tumors. Treated animals presented smaller tumors, regardless of the therapeutic regimen, and far fewer lung metastases in both quantity and dimension compared with the controls. The expression of vascular endothelial growth factor and CD34 were significantly decreased in renal tumors of treated animals compared with the controls. Our findings suggest that blockade of RAS decreases tumor proliferation and metastatic capacity of RCC in this experimental model. Copyright © 2015 Elsevier Inc. All rights reserved.

Role of Mas receptor in renal blood flow response to angiotensin (1-7) in male and female rats.

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Nematbakhsh, Mehdi; Safari, Tahereh

2014-01-01

Epidemiologic and clinical studies have shown that progression of renal disease in male is faster than that in female. However, the exact mechanisms are not well recognized. Angiotensin (1-7) (Ang 1-7) receptor, called "Mas", is an element in the depressor arm of renin angiotensin system (RAS), and its expression is enhanced in females. We test the hypothesis that Mas receptor (MasR) blockade (A779) attenuates renal blood flow (RBF) in response to infusion of graded doses of Ang 1-7 in female rats. Male and female Wistar rats were anesthetized and catheterized. Then, the mean arterial pressure (MAP), RBF, and controlled renal perfusion pressure (RPP) responses to infusion of graded doses of Ang 1-7 (100-1000 ng/kg/min i.v.) with and without A779 were measured in the animals. Basal MAP, RPP, RBF, and renal vascular resistance (RVR) were not significantly different between the two groups. After Ang 1-7 administration, RPP was controlled at a constant level. However, RBF increased in a dose-related manner in response to Ang 1-7 infusion in both male and female rats (Pdoserenal diseases.

Oxytocin differently regulates pressor responses to stress in WKY and SHR rats: the role of central oxytocin and V1a receptors.

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Wsol, A; Szczepanska-Sadowska, E; Kowalewski, S; Puchalska, L; Cudnoch-Jedrzejewska, A

2014-01-01

The role of central oxytocin in the regulation of cardiovascular parameters under resting conditions and during acute stress was investigated in male normotensive Wistar-Kyoto (WKY; n = 40) and spontaneously hypertensive rats (SHR; n = 28). In Experiment 1, mean arterial blood pressure (MABP) and heart rate (HR) were recorded in WKY and SHR rats at rest and after an air-jet stressor during intracerebroventricular (ICV) infusions of vehicle, oxytocin or oxytocin receptor (OTR) antagonist. In Experiment 2, the effects of vehicle, oxytocin and OTR antagonist were determined in WKY rats after prior administration of a V1a vasopressin receptor (V1aR) antagonist. Resting MABP and HR were not affected by any of the ICV infusions either in WKY or in SHR rats. In control experiments (vehicle), the pressor response to stress was significantly higher in SHR. Oxytocin enhanced the pressor response to stress in the WKY rats but reduced it in SHR. During V1aR blockade, oxytocin infusion entirely abolished the pressor response to stress in WKY rats. Combined blockade of V1aR and OTR elicited a significantly greater MABP response to stress than infusion of V1a antagonist and vehicle. This study reveals significant differences in the regulation of blood pressure in WKY and SHR rats during alarming stress. Specifically, the augmentation of the pressor response to stress by exogenous oxytocin in WKY rats is caused by its interaction with V1aR, and endogenous oxytocin regulates the magnitude of the pressor response to stress in WKY rats by simultaneous interaction with OTR and V1aR.

Expression of transient receptor potential ankyrin 1 (TRPA1 and its role in insulin release from rat pancreatic beta cells.

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De-Shou Cao

Full Text Available Several transient receptor potential (TRP channels are expressed in pancreatic beta cells and have been proposed to be involved in insulin secretion. However, the endogenous ligands for these channels are far from clear. Here, we demonstrate the expression of the transient receptor potential ankyrin 1 (TRPA1 ion channel in the pancreatic beta cells and its role in insulin release. TRPA1 is an attractive candidate for inducing insulin release because it is calcium permeable and is activated by molecules that are produced during oxidative glycolysis.Immunohistochemistry, RT-PCR, and Western blot techniques were used to determine the expression of TRPA1 channel. Ca²⁺ fluorescence imaging and electrophysiology (voltage- and current-clamp techniques were used to study the channel properties. TRPA1-mediated insulin release was determined using ELISA.TRPA1 is abundantly expressed in a rat pancreatic beta cell line and freshly isolated rat pancreatic beta cells, but not in pancreatic alpha cells. Activation of TRPA1 by allyl isothiocyanate (AITC, hydrogen peroxide (H₂O₂, 4-hydroxynonenal (4-HNE, and cyclopentenone prostaglandins (PGJ₂ and a novel agonist methylglyoxal (MG induces membrane current, depolarization, and Ca²⁺ influx leading to generation of action potentials in a pancreatic beta cell line and primary cultured pancreatic beta cells. Activation of TRPA1 by agonists stimulates insulin release in pancreatic beta cells that can be inhibited by TRPA1 antagonists such as HC030031 or AP-18 and by RNA interference. TRPA1-mediated insulin release is also observed in conditions of voltage-gated Na⁺ and Ca²⁺ channel blockade as well as ATP sensitive potassium (K(ATP channel activation.We propose that endogenous and exogenous ligands of TRPA1 cause Ca²⁺ influx and induce basal insulin release and that TRPA1-mediated depolarization acts synergistically with K(ATP channel blockade to facilitate insulin release.

5-HT4-receptors modulate induction of long-term depression but not potentiation at hippocampal output synapses in acute rat brain slices.

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Matthias Wawra

Full Text Available The subiculum is the principal target of CA1 pyramidal cells and mediates hippocampal output to various cortical and subcortical regions of the brain. The majority of subicular pyramidal cells are burst-spiking neurons. Previous studies indicated that high frequency stimulation in subicular burst-spiking cells causes presynaptic NMDA-receptor dependent long-term potentiation (LTP whereas low frequency stimulation induces postsynaptic NMDA-receptor-dependent long-term depression (LTD. In the present study, we investigate the effect of 5-hydroxytryptamine type 4 (5-HT4 receptor activation and blockade on both forms of synaptic plasticity in burst-spiking cells. We demonstrate that neither activation nor block of 5-HT4 receptors modulate the induction or expression of LTP. In contrast, activation of 5-HT4 receptors facilitates expression of LTD, and block of the 5-HT4 receptor prevents induction of short-term depression and LTD. As 5-HT4 receptors are positively coupled to adenylate cyclase 1 (AC1, 5-HT4 receptors might modulate PKA activity through AC1. Since LTD is blocked in the presence of 5-HT4 receptor antagonists, our data are consistent with 5-HT4 receptor activation by ambient serotonin or intrinsically active 5-HT4 receptors. Our findings provide new insight into aminergic modulation of hippocampal output.

Nicotine and 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone induce cyclooxygenase-2 activity in human gastric cancer cells: Involvement of nicotinic acetylcholine receptor (nAChR) and β-adrenergic receptor signaling pathways

International Nuclear Information System (INIS)

Shin, Vivian Yvonne; Jin, H.C.; Ng, Enders K.O.; Yu Jun; Leung, W.K.; Cho, C.H.; Sung, J.J.Y.

2008-01-01

Induction of cyclooxygenase-2 (COX-2) associates with cigarette smoke exposure in many malignancies. Nicotine and its derivative, 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK), are the two important components in cigarette smoke that contributes to cancer development. However, the molecular mechanism(s) by which nicotine or NNK promotes gastric carcinogenesis remains largely unknown. We found that nicotine and NNK significantly enhanced cell proliferation in AGS cells that expressed both alpha7 nicotinic acetylcholine receptor (α7 nAChR) and β-adrenergic receptors. Treatment of cells with α-bungarotoxin (α-BTX, α7nAChR antagonist) or propranolol (β-adrenergic receptor antagonist) blocked NNK-induced COX-2/PGE 2 and cell proliferation, while nicotine-mediated cell growth and COX-2/PGE 2 induction can only be suppressed by propranolol, but not α-BTX. Moreover, in contrast to the dependence of growth promoting effect of nicotine on Erk activation, inhibitor of p38 mitogen-activated protein kinase (MAPK) repressed NNK-induced COX-2 upregulation and resulted in suppression of cell growth. In addition, nicotine and NNK mediated COX-2 induction via different receptors to modulate several G1/S transition regulatory proteins and promote gastric cancer cell growth. Selective COX-2 inhibitor (SC-236) caused G1 arrest and abrogated nicotine/NNK-induced cell proliferation. Aberrant expression of cyclin D1 and other G1 regulatory proteins are reversed by blockade of COX-2. These results pointed to the importance of adrenergic and nicotinic receptors in gastric tumor growth through MAPK/COX-2 activation, which may perhaps provide a chemoprevention strategy for cigarette smoke-related gastric carcinogenesis

NGF blockade at early times during bone cancer development attenuates bone destruction and increases limb use.

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McCaffrey, Gwen; Thompson, Michelle L; Majuta, Lisa; Fealk, Michelle N; Chartier, Stephane; Longo, Geraldine; Mantyh, Patrick W

2014-12-01

Studies in animals and humans show that blockade of nerve growth factor (NGF) attenuates both malignant and nonmalignant skeletal pain. While reduction of pain is important, a largely unanswered question is what other benefits NGF blockade might confer in patients with bone cancer. Using a mouse graft model of bone sarcoma, we demonstrate that early treatment with an NGF antibody reduced tumor-induced bone destruction, delayed time to bone fracture, and increased the use of the tumor-bearing limb. Consistent with animal studies in osteoarthritis and head and neck cancer, early blockade of NGF reduced weight loss in mice with bone sarcoma. In terms of the extent and time course of pain relief, NGF blockade also reduced pain 40% to 70%, depending on the metric assessed. Importantly, this analgesic effect was maintained even in animals with late-stage disease. Our results suggest that NGF blockade immediately upon detection of tumor metastasis to bone may help preserve the integrity and use, delay the time to tumor-induced bone fracture, and maintain body weight. ©2014 American Association for Cancer Research.

Striatal dopamine D1 and D2 receptors: widespread influences on methamphetamine-induced dopamine and serotonin neurotoxicity.

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Gross, Noah B; Duncker, Patrick C; Marshall, John F

2011-11-01

Methamphetamine (mAMPH) is an addictive psychostimulant drug that releases monoamines through nonexocytotic mechanisms. In animals, binge mAMPH dosing regimens deplete markers for monoamine nerve terminals, for example, dopamine and serotonin transporters (DAT and SERT), in striatum and cerebral cortex. Although the precise mechanism of mAMPH-induced damage to monoaminergic nerve terminals is uncertain, both dopamine D1 and D2 receptors are known to be important. Systemic administration of dopamine D1 or D2 receptor antagonists to rodents prevents mAMPH-induced damage to striatal dopamine nerve terminals. Because these studies employed systemic antagonist administration, the specific brain regions involved remain to be elucidated. The present study examined the contribution of dopamine D1 and D2 receptors in striatum to mAMPH-induced DAT and SERT neurotoxicities. In this experiment, either the dopamine D1 antagonist, SCH23390, or the dopamine D2 receptor antagonist, sulpiride, was intrastriatally infused during a binge mAMPH regimen. Striatal DAT and cortical, hippocampal, and amygdalar SERT were assessed as markers of mAMPH-induced neurotoxicity 1 week following binge mAMPH administration. Blockade of striatal dopamine D1 or D2 receptors during an otherwise neurotoxic binge mAMPH regimen produced widespread protection against mAMPH-induced striatal DAT loss and cortical, hippocampal, and amygdalar SERT loss. This study demonstrates that (1) dopamine D1 and D2 receptors in striatum, like nigral D1 receptors, are needed for mAMPH-induced striatal DAT reductions, (2) these same receptors are needed for mAMPH-induced SERT loss, and (3) these widespread influences of striatal dopamine receptor antagonists are likely attributable to circuits connecting basal ganglia to thalamus and cortex. Copyright © 2011 Wiley-Liss, Inc.

Transient receptor potential channel ankyrin-1 is not a cold sensor for autonomic thermoregulation in rodents.

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de Oliveira, Cristiane; Garami, Andras; Lehto, Sonya G; Pakai, Eszter; Tekus, Valeria; Pohoczky, Krisztina; Youngblood, Beth D; Wang, Weiya; Kort, Michael E; Kym, Philip R; Pinter, Erika; Gavva, Narender R; Romanovsky, Andrej A

2014-03-26

The rodent transient receptor potential ankyrin-1 (TRPA1) channel has been hypothesized to serve as a temperature sensor for thermoregulation in the cold. We tested this hypothesis by using deletion of the Trpa1 gene in mice and pharmacological blockade of the TRPA1 channel in rats. In both Trpa1(-/-) and Trpa1(+/+) mice, severe cold exposure (8°C) resulted in decreases of skin and deep body temperatures to ∼8°C and 13°C, respectively, both temperatures being below the reported 17°C threshold temperature for TRPA1 activation. Under these conditions, Trpa1(-/-) mice had the same dynamics of body temperature as Trpa1(+/+) mice and showed no weakness in the tail skin vasoconstriction response or thermogenic response to cold. In rats, the effects of pharmacological blockade were studied by using two chemically unrelated TRPA1 antagonists: the highly potent and selective compound A967079, which had been characterized earlier, and the relatively new compound 43 ((4R)-1,2,3,4-tetrahydro-4-[3-(3-methoxypropoxy)phenyl]-2-thioxo-5H-indeno[1,2-d]pyrimidin-5-one), which we further characterized in the present study and found to be highly potent (IC50 against cold of ∼8 nm) and selective. Intragastric administration of either antagonist at 30 mg/kg before severe (3°C) cold exposure did not affect the thermoregulatory responses (deep body and tail skin temperatures) of rats, even though plasma concentrations of both antagonists well exceeded their IC50 value at the end of the experiment. In the same experimental setup, blocking the melastatin-8 (TRPM8) channel with AMG2850 (30 mg/kg) attenuated cold-defense mechanisms and led to hypothermia. We conclude that TRPA1 channels do not drive autonomic thermoregulatory responses to cold in rodents.

Chronic Blockade of Brain Endothelin Receptor Type-A (ETA Reduces Blood Pressure and Prevents Catecholaminergic Overactivity in the Right Olfactory Bulb of DOCA-Salt Hypertensive Rats

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Luis R. Cassinotti

2018-02-01

Full Text Available Overactivity of the sympathetic nervous system and central endothelins (ETs are involved in the development of hypertension. Besides the well-known brain structures involved in the regulation of blood pressure like the hypothalamus or locus coeruleus, evidence suggests that the olfactory bulb (OB also modulates cardiovascular function. In the present study, we evaluated the interaction between the endothelinergic and catecholaminergic systems in the OB of deoxycorticosterone acetate (DOCA-salt hypertensive rats. Following brain ET receptor type A (ETA blockade by BQ610 (selective antagonist, transcriptional, traductional, and post-traductional changes in tyrosine hydroxylase (TH were assessed in the OB of normotensive and DOCA-salt hypertensive rats. Time course variations in systolic blood pressure and heart rate were also registered. Results showed that ETA blockade dose dependently reduced blood pressure in hypertensive rats, but it did not change heart rate. It also prevented the increase in TH activity and expression (mRNA and protein in the right OB of hypertensive animals. However, ETA blockade did not affect hemodynamics or TH in normotensive animals. Present results support that brain ETA are not involved in blood pressure regulation in normal rats, but they significantly contribute to chronic blood pressure elevation in hypertensive animals. Changes in TH activity and expression were observed in the right but not in the left OB, supporting functional asymmetry, in line with previous studies regarding cardiovascular regulation. Present findings provide further evidence on the role of ETs in the regulation of catecholaminergic activity and the contribution of the right OB to DOCA-salt hypertension.

Chronic Blockade of Brain Endothelin Receptor Type-A (ETA) Reduces Blood Pressure and Prevents Catecholaminergic Overactivity in the Right Olfactory Bulb of DOCA-Salt Hypertensive Rats.

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Cassinotti, Luis R; Guil, María J; Schöller, Mercedes I; Navarro, Mónica P; Bianciotti, Liliana G; Vatta, Marcelo S

2018-02-27

Overactivity of the sympathetic nervous system and central endothelins (ETs) are involved in the development of hypertension. Besides the well-known brain structures involved in the regulation of blood pressure like the hypothalamus or locus coeruleus, evidence suggests that the olfactory bulb (OB) also modulates cardiovascular function. In the present study, we evaluated the interaction between the endothelinergic and catecholaminergic systems in the OB of deoxycorticosterone acetate (DOCA)-salt hypertensive rats. Following brain ET receptor type A (ET A ) blockade by BQ610 (selective antagonist), transcriptional, traductional, and post-traductional changes in tyrosine hydroxylase (TH) were assessed in the OB of normotensive and DOCA-salt hypertensive rats. Time course variations in systolic blood pressure and heart rate were also registered. Results showed that ET A blockade dose dependently reduced blood pressure in hypertensive rats, but it did not change heart rate. It also prevented the increase in TH activity and expression (mRNA and protein) in the right OB of hypertensive animals. However, ET A blockade did not affect hemodynamics or TH in normotensive animals. Present results support that brain ET A are not involved in blood pressure regulation in normal rats, but they significantly contribute to chronic blood pressure elevation in hypertensive animals. Changes in TH activity and expression were observed in the right but not in the left OB, supporting functional asymmetry, in line with previous studies regarding cardiovascular regulation. Present findings provide further evidence on the role of ETs in the regulation of catecholaminergic activity and the contribution of the right OB to DOCA-salt hypertension.

Integrated cannabinoid CB1 receptor transmission within the amygdala-prefrontal cortical pathway modulates neuronal plasticity and emotional memory encoding.

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Tan, Huibing; Lauzon, Nicole M; Bishop, Stephanie F; Bechard, Melanie A; Laviolette, Steven R

2010-06-01

The cannabinoid CB1 receptor system is functionally involved in the processing and encoding of emotionally salient sensory information, learning and memory. The CB1 receptor is found in high concentrations in brain structures that are critical for emotional processing, including the basolateral amygdala (BLA) and the medial prefrontal cortex (mPFC). In addition, synaptic plasticity in the form of long-term potentiation (LTP) within the BLA > mPFC pathway is an established correlate of exposure to emotionally salient events. We performed a series of in vivo LTP studies by applying tetanic stimulation to the BLA combined with recordings of local field potentials within prelimbic cortical (PLC) region of the rat mPFC. Systemic pretreatment with AM-251 dose dependently blocked LTP along the BLA-PLC pathway and also the behavioral acquisition of conditioned fear memories. We next performed a series of microinfusion experiments wherein CB1 receptor transmission within the BLA > PLC circuit was pharmacologically blocked. Asymmetrical, interhemispheric blockade of CB1 receptor transmission along the BLA > PLC pathway prevented the acquisition of emotionally salient associative memory. Our results indicate that coordinated CB1 receptor transmission within the BLA > PLC pathway is critically involved in the encoding of emotional fear memories and modulates neural plasticity related to the encoding of emotionally salient associative learning.

Discovery of Indazoles as Potent, Orally Active Dual Neurokinin 1 Receptor Antagonists and Serotonin Transporter Inhibitors for the Treatment of Depression.

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Degnan, Andrew P; Tora, George O; Huang, Hong; Conlon, David A; Davis, Carl D; Hanumegowda, Umesh M; Hou, Xiaoping; Hsiao, Yi; Hu, Joanna; Krause, Rudolph; Li, Yu-Wen; Newton, Amy E; Pieschl, Rick L; Raybon, Joseph; Rosner, Thorsten; Sun, Jung-Hui; Taber, Matthew T; Taylor, Sarah J; Wong, Michael K; Zhang, Huiping; Lodge, Nicholas J; Bronson, Joanne J; Macor, John E; Gillman, Kevin W

2016-12-21

Combination studies of neurokinin 1 (NK1) receptor antagonists and serotonin-selective reuptake inhibitors (SSRIs) have shown promise in preclinical models of depression. Such a combination may offer important advantages over the current standard of care. Herein we describe the discovery and optimization of an indazole-based chemotype to provide a series of potent dual NK1 receptor antagonists/serotonin transporter (SERT) inhibitors to overcome issues of ion channel blockade. This effort culminated in the identification of compound 9, an analogue that demonstrated favorable oral bioavailability, excellent brain uptake, and robust in vivo efficacy in a validated depression model. Over the course of this work, a novel heterocycle-directed asymmetric hydrogenation was developed to facilitate installation of the key stereogenic center.

Ionotropic excitatory amino acid receptor ligands. Synthesis and pharmacology of a new amino acid AMPA antagonist

DEFF Research Database (Denmark)

Madsen, U; Sløk, F A; Stensbøl, T B

2000-01-01

We have previously described the potent and selective (RS)-2-amino-3-(3-hydroxy-5-methyl-4-isoxazolyl)propionic acid (AMPA) receptor agonist, (RS)-2-amino-3-(3-carboxy-5-methyl-4-isoxazolyl)propionic acid (ACPA), and the AMPA receptor antagonist (RS)-2-amino-3-[3-(carboxymethoxy)-5-methyl-4...... excitatory amino acid (EAA) receptors using receptor binding and electrophysiological techniques, and for activity at metabotropic EAA receptors using second messenger assays. Compounds 1 and 4 were essentially inactive. (RS)-2-Amino-3-[3-(2-carboxyethyl)-5-methyl-4-isoxazolyl]propionic acid (ACMP, 2......-isoxazolyl]propionic acid (AMOA). Using these AMPA receptor ligands as leads, a series of compounds have been developed as tools for further elucidation of the structural requirements for activation and blockade of AMPA receptors. The synthesized compounds have been tested for activity at ionotropic...

Blockade of human P2X7 receptor function with a monoclonal antibody.

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Buell, G; Chessell, I P; Michel, A D; Collo, G; Salazzo, M; Herren, S; Gretener, D; Grahames, C; Kaur, R; Kosco-Vilbois, M H; Humphrey, P P

1998-11-15

A monoclonal antibody (MoAb) specific for the human P2X7 receptor was generated in mice. As assessed by flow cytometry, the MoAb labeled human blood-derived macrophage cells natively expressing P2X7 receptors and cells transfected with human P2X7 but not other P2X receptor types. The MoAb was used to immunoprecipitate the human P2X7 receptor protein, and in immunohistochemical studies on human lymphoid tissue, P2X7 receptor labeling was observed within discrete areas of the marginal zone of human tonsil sections. The antibody also acted as a selective antagonist of human P2X7 receptors in several functional studies. Thus, whole cell currents, elicited by the brief application of 2',3'-(4-benzoyl)-benzoyl-ATP in cells expressing human P2X7, were reduced in amplitude by the presence of the MoAb. Furthermore, preincubation of human monocytic THP-1 cells with the MoAb antagonized the ability of P2X7 agonists to induce the release of interleukin-1beta.

Elevated N-terminal pro-brain natriuretic peptide levels predict an enhanced anti-hypertensive and anti-proteinuric benefit of dietary sodium restriction and diuretics, but not angiotensin receptor blockade, in proteinuric renal patients.

Science.gov (United States)

Slagman, Maartje C J; Waanders, Femke; Vogt, Liffert; Damman, Kevin; Hemmelder, Marc; Navis, Gerjan; Laverman, Gozewijn D

2012-03-01

Renin-angiotensin aldosterone system (RAAS) blockade only partly reduces blood pressure, proteinuria and renal and cardiovascular risk in chronic kidney disease (CKD) but often requires sodium targeting [i.e. low sodium diet (LS) and/or diuretics] for optimal efficacy. However, both under- and overtitration of sodium targeting can easily occur. We evaluated whether N-terminal pro-brain natriuretic peptide (NT-proBNP), a biomarker of volume expansion, predicts the benefits of sodium targeting in CKD patients. In a cross-over randomized controlled trial, 33 non-diabetic CKD patients (proteinuria 3.8 ± 0.4 g/24 h, blood pressure 143/86 ± 3/2 mmHg, creatinine clearance 89 ± 5 mL/min) were treated during 6-week periods with placebo, angiotensin receptor blockade (ARB; losartan 100 mg/day) and ARB plus diuretics (losartan 100 mg/day plus hydrochlorothiazide 25 mg/day), combined with LS (93 ± 52 mmol Na(+)/24 h) and regular sodium diet (RS; 193 ± 62 mmol Na(+)/24 h, P diuretics and was normalized by ARB + diuretic + LS [39 (26-59) pg/mL, P = 0.65 versus controls]. NT-proBNP levels above the upper limit of normal (>125 pg/mL) predicted a larger reduction of blood pressure and proteinuria by LS and diuretics but not by ARB, during all steps of the titration regimen. Elevated NT-proBNP levels predict an enhanced anti-hypertensive and anti-proteinuric benefit of sodium targeting, but not RAAS blockade, in proteinuric CKD patients. Importantly, this applies to the untreated condition, as well as to the subsequent treatment steps, consisting of RAAS blockade and even RAAS blockade combined with diuretics. NT-proBNP can be a useful tool to identify CKD patients in whom sodium targeting can improve blood pressure and proteinuria.

Coulomb blockade induced by magnetic field

International Nuclear Information System (INIS)

Kusmartsev, F.V.

1992-01-01

In this paper, the authors found that a Coulomb blockade can be induced by magnetic field. The authors illustrated this effect on the example of a ring consisting of two and many Josephson junctions. For the ring with two junctions we present an exact solution. The transition into Coulomb blockade state on a ring transforms into a linear array of Josephson junctions, although in latter case the effect of magnetic field disappears. In the state of Coulomb blockade the magnetization may be both diamagnetic and paramagnetic. The Coulomb blockade may also be removed by external magnetic field

Effects of sugammadex on incidence of postoperative residual neuromuscular blockade: a randomized, controlled study.

Science.gov (United States)

Brueckmann, B; Sasaki, N; Grobara, P; Li, M K; Woo, T; de Bie, J; Maktabi, M; Lee, J; Kwo, J; Pino, R; Sabouri, A S; McGovern, F; Staehr-Rye, A K; Eikermann, M

2015-11-01

This study aimed to investigate whether reversal of rocuronium-induced neuromuscular blockade with sugammadex reduced the incidence of residual blockade and facilitated operating room discharge readiness. Adult patients undergoing abdominal surgery received rocuronium, followed by randomized allocation to sugammadex (2 or 4 mg kg(-1)) or usual care (neostigmine/glycopyrrolate, dosing per usual care practice) for reversal of neuromuscular blockade. Timing of reversal agent administration was based on the providers' clinical judgement. Primary endpoint was the presence of residual neuromuscular blockade at PACU admission, defined as a train-of-four (TOF) ratio sugammadex patients and 33 out of 76 (43.4%) usual care patients had TOF-Watch SX-assessed residual neuromuscular blockade at PACU admission (odds ratio 0.0, 95% CI [0-0.06], Psugammadex vs usual care (14.7 vs. 18.6 min respectively; P=0.02). After abdominal surgery, sugammadex reversal eliminated residual neuromuscular blockade in the PACU, and shortened the time from start of study medication administration to the time the patient was ready for discharge from the operating room. Clinicaltrials.gov:NCT01479764. © The Author 2015. Published by Oxford University Press on behalf of the British Journal of Anaesthesia. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Multivalent Fcγ-receptor engagement by a hexameric Fc-fusion protein triggers Fcγ-receptor internalisation and modulation of Fcγ-receptor functions.

Science.gov (United States)

Qureshi, O S; Rowley, T F; Junker, F; Peters, S J; Crilly, S; Compson, J; Eddleston, A; Björkelund, H; Greenslade, K; Parkinson, M; Davies, N L; Griffin, R; Pither, T L; Cain, K; Christodoulou, L; Staelens, L; Ward, E; Tibbitts, J; Kiessling, A; Smith, B; Brennan, F R; Malmqvist, M; Fallah-Arani, F; Humphreys, D P

2017-12-06

Engagement of Fcγ-receptors triggers a range of downstream signalling events resulting in a diverse array of immune functions. As a result, blockade of Fc-mediated function is an important strategy for the control of several autoimmune and inflammatory conditions. We have generated a hexameric-Fc fusion protein (hexameric-Fc) and tested the consequences of multi-valent Fcγ-receptor engagement in in vitro and in vivo systems. In vitro engagement of hexameric-Fc with FcγRs showed complex binding interactions that altered with receptor density and triggered the internalisation and degradation of Fcγ-receptors. This caused a disruption of Fc-binding and phagocytosis. In vivo, in a mouse ITP model we observed a short half-life of hexameric-Fc but were nevertheless able to observe inhibition of platelet phagocytosis several days after hexameric-Fc dosing. In cynomolgus monkeys, we again observed a short half-life, but were able to demonstrate effective FcγR blockade. These findings demonstrate the ability of multi-valent Fc-based therapeutics to interfere with FcγR function and a potential mechanism through which they could have a sustained effect; the internalisation and degradation of FcγRs.

Adenosine A1 receptors (A1Rs) play a critical role in osteoclast formation and function

Science.gov (United States)

Kara, Firas M.; Chitu, Violeta; Sloane, Jennifer; Axelrod, Matthew; Fredholm, Bertil B.; Stanley, E. Richard; Cronstein, Bruce N.

2010-01-01

Adenosine regulates a wide variety of physiological processes via interaction with one or more G-protein-coupled receptors (A1R, A2AR, A2BR, and A3R). Because A1R occupancy promotes fusion of human monocytes to form giant cells in vitro, we determined whether A1R occupancy similarly promotes osteoclast function and formation. Bone marrow cells (BMCs) were harvested from C57Bl/6 female mice or A1R-knockout mice and their wild-type (WT) littermates and differentiated into osteoclasts in the presence of colony stimulating factor-1 and receptor activator of NF-κB ligand in the presence or absence of the A1R antagonist 1,3-dipropyl-8-cyclopentyl xanthine (DPCPX). Osteoclast morphology was analyzed in tartrate-resistant acid phosphatase or F-actin-stained samples, and bone resorption was evaluated by toluidine blue staining of dentin. BMCs from A1R-knockout mice form fewer osteoclasts than BMCs from WT mice, and the A1R antagonist DPCPX inhibits osteoclast formation (IC50=1 nM), with altered morphology and reduced ability to resorb bone. A1R blockade increased ubiquitination and degradation of TRAF6 in RAW264.7 cells induced to differentiate into osteoclasts. These studies suggest a critical role for adenosine in bone homeostasis via interaction with adenosine A1R and further suggest that A1R may be a novel pharmacologic target to prevent the bone loss associated with inflammatory diseases and menopause.—Kara, F. M., Chitu, V., Sloane, J., Axelrod, M., Fredholm, B. B., Stanley, R., Cronstein, B. N. Adenosine A1 receptors (A1Rs) play a critical role in osteoclast formation and function. PMID:20181934

Contemporary views on the lawfulness of naval blockades

NARCIS (Netherlands)

Fink, M.D.

2011-01-01

The traditional law of blockade has several technical requirements that if not met renders a blockade unlawful. These traditional requirements balance the interests of the belligerent and neutrals. A more contemporary view on the law of blockade, however, emphasizes that blockades are also subject

Progesterone receptor blockade in human breast cancer cells decreases cell cycle progression through G2/M by repressing G2/M genes

International Nuclear Information System (INIS)

Clare, Susan E.; Gupta, Akash; Choi, MiRan; Ranjan, Manish; Lee, Oukseub; Wang, Jun; Ivancic, David Z.; Kim, J. Julie; Khan, Seema A.

2016-01-01

The synthesis of specific, potent progesterone antagonists adds potential agents to the breast cancer prevention and treatment armamentarium. The identification of individuals who will benefit from these agents will be a critical factor for their clinical success. We utilized telapristone acetate (TPA; CDB-4124) to understand the effects of progesterone receptor (PR) blockade on proliferation, apoptosis, promoter binding, cell cycle progression, and gene expression. We then identified a set of genes that overlap with human breast luteal-phase expressed genes and signify progesterone activity in both normal breast cells and breast cancer cell lines. TPA administration to T47D cells results in a 30 % decrease in cell number at 24 h, which is maintained over 72 h only in the presence of estradiol. Blockade of progesterone signaling by TPA for 24 h results in fewer cells in G2/M, attributable to decreased expression of genes that facilitate the G2/M transition. Gene expression data suggest that TPA affects several mechanisms that progesterone utilizes to control gene expression, including specific post-translational modifications, and nucleosomal organization and higher order chromatin structure, which regulate access of PR to its DNA binding sites. By comparing genes induced by the progestin R5020 in T47D cells with those increased in the luteal-phase normal breast, we have identified a set of genes that predict functional progesterone signaling in tissue. These data will facilitate an understanding of the ways in which drugs such as TPA may be utilized for the prevention, and possibly the therapy, of human breast cancer. The online version of this article (doi:10.1186/s12885-016-2355-5) contains supplementary material, which is available to authorized users

Influence of age, body temperature, GABAA receptor inhibition and caffeine on the Hering-Breuer inflation reflex in unanesthetized rat pups.

Science.gov (United States)

Arnal, Ashley V; Gore, Julie L; Rudkin, Alison; Bartlett, Donald; Leiter, J C

2013-03-01

We measured the duration of apnea induced by sustained end-inspiratory lung inflation (the Hering Breuer Reflex, HBR) in unanesthetized infant rat pups aged 4 days (P4) to P20 at body temperatures of 32°C and 36°C. The expiratory prolongation elicited by the HBR lasted longer in the younger pups and lasted longer at the higher body temperature. Blockade of adenosine receptors by caffeine following injection into the cisterna magna (ICM) significantly blunted the thermal prolongation of the HBR. Blockade of gama-amino-butyric acid A (GABAA) receptors by pre-treatment with ICM bicuculline had no effect on the HBR duration at either body temperature. To test the hypothesis that developmental maturation of GABAergic inhibition of breathing was modifying the response to bicuculline, we pretreated rat pups with systemically administered bumetanide to lower the intracellular chloride concentration, and repeated the bicuculline studies. Bicuculline still did not alter the HBR at either temperature after bumetanide treatment. We administered PSB-36, a selective adenosine A1 receptor antagonist, and this drug treatment did not modify the HBR. We conclude that caffeine blunts the thermal prolongation of the HBR, probably by blocking adenosine A2a receptors. The thermally sensitive adenosinergic prolongation of the HBR in these intact animals does not seem to depend on GABAA receptors. Copyright © 2013 Elsevier B.V. All rights reserved.

Positron emission tomography study of pindolol occupancy of 5-HT1A receptors in humans: preliminary analyses

International Nuclear Information System (INIS)

Martinez, Diana; Mawlawi, Osama; Hwang, Dah-Ren; Kent, Justine; Simpson, Norman; Parsey, Ramin V.; Hashimoto, Tomoki; Slifstein, Mark; Huang Yiyun; Heertum, Ronald van; Abi-Dargham, Anissa; Caltabiano, Stephen; Malizia, Andrea; Cowley, Hugh; Mann, J. John; Laruelle, Marc

2000-01-01

Preclinical studies in rodents suggest that augmentation of serotonin reuptake inhibitors (SSRIs) therapy by the 5-hydroxytryptamine 1A (5-HT 1A ) receptor agent pindolol might reduce the delay between initiation of treatment and antidepressant response. This hypothesis is based on the ability of pindolol to potentiate the increase in serotonin (5-HT) transmission induced by SSRIs, an effect achieved by blockade of the 5-HT 1A autoreceptors in the dorsal raphe nuclei (DRN). However, placebo-controlled clinical studies of pindolol augmentation of antidepressant therapy have reported inconsistent results. Here, we evaluated the occupancy of 5-HT 1A receptors following treatment with controlled release pindolol in nine healthy volunteers with positron-emission tomography (PET). Each subject was studied four times: at baseline (scan 1), following 1 week of oral administration of pindolol CR (7.5 mg/day) at peak level, 4 h after the dose (scan 2), and at 10 h following the dose (scan 3), and following one dose of pindolol CR (30 mg) (at peak level, 4 h) (scan 4). Pindolol occupancy of 5-HT 1A receptors was evaluated in the DRN and cortical regions as the decrease in binding potential (BP) of the radiolabelled selective 5-HT 1A antagonist [carbonyl- 11 C]WAY-100635 or [carbonyl- 11 C] N-(2-(4-(2-methoxyphenyl)-1-piperazinyl)ethyl)-N-(2-pyridyl) cyclohexanecarboxamide abbreviated as [ 11 C]WAY-100635. Pindolol dose-dependently decreased [ 11 C]WAY-100635 BP. Combining all the regions, occupancy was 20 ± 8% at scan 2, 14 ± 8% at scan 3, and 44 ± 8% at scan 4. The results of this study suggest that at doses used in clinical studies of augmentation of the SSRI effect by pindolol (2.5 mg t.i.d.), the occupancy of 5-HT 1A receptors is moderate and highly variable between subjects. This factor might explain the variable results obtained in clinical studies. On the other hand, at each dose tested, pindolol occupancy of 5-HT 1A receptors was higher in the DRN compared to

Predicting treatment response from dopamine D2/3 receptor bnding potential? - A study in antipsychotic-naïve patients with schizophrenia

DEFF Research Database (Denmark)

Wulff, Sanne; Pinborg, Lars Hageman; Svarer, Claus

of antipsychotic compounds on the positive symptoms. Furthermore, blockade of striatal dopamine D2 receptors have in studies shown to associate negatively with subjective well-being. Our main aim was to explore a possible predictive value of striatal dopamine D2/3 receptor binding potential (BPp) for treatment...... of 29 antipsychotic-naïve patients with schizophrenia and 26 matched healthy controls, SPECT with [123l]-IBZM was used to examine the BPP of striatal dopamine D2/3 receptors. The participants were examined at baseline and after 6 weeks of treatment with a selective D2/3 receptor antagonist, amisulpride....... Results: We found a significant inverse correlation between the striatal BPp at baseline and improvement of positive symptoms (p=0.046; R squared = 0.152) after six weeks of treatment with amisulpride. There was no association between the blockade of the D2/3 receptors and improvement of positive symptoms...

Panicolytic-like effects caused by substantia nigra pars reticulata pretreatment with low doses of endomorphin-1 and high doses of CTOP or the NOP receptors antagonist JTC-801 in male Rattus norvegicus.

Science.gov (United States)

da Silva, Juliana Almeida; Biagioni, Audrey Franceschi; Almada, Rafael Carvalho; de Freitas, Renato Leonardo; Coimbra, Norberto Cysne

2017-10-01

Gamma-aminobutyric acid (GABA)ergic neurons of the substantia nigra pars reticulata (SNpr) are connected to the deep layers of the superior colliculus (dlSC). The dlSC, in turn, connect with the SNpr through opioid projections. Nociceptin/orphanin FQ peptide (N/OFQ) is a natural ligand of a Gi protein-coupled nociceptin receptor (ORL1; NOP) that is also found in the SNpr. Our hypothesis is that tectonigral opioid pathways and intranigral orphanin-mediated mechanisms modulate GABAergic nigrotectal connections. Therefore, the aim of this work was to study the role of opioid and NOP receptors in the SNpr during the modulation of defence reactions organised by the dlSC. The SNpr was pretreated with either opioid or NOP receptor agonists and antagonists, followed by dlSC treatment with bicuculline. Blockade of GABA A receptors in the dlSC elicited fear-related defensive behaviour. Pretreatment of the SNpr with naloxone benzoylhydrazone (NalBzoH), a μ-, δ-, and κ 1 -opioid receptor antagonist as well as a NOP receptor antagonist, decreased the aversive effect of bicuculline treatment on the dlSC. Either μ-opioid receptor activation or blockade by SNpr microinjection of endomorphin-1 (EM-1) and CTOP promoted pro-aversive and anti-aversive actions, respectively, that modulated the defensive responses elicited by bicuculline injection into the dlSC. Pretreatment of the SNpr with the selective NOP receptor antagonist JTC801 decreased the aversive effect of bicuculline, and microinjections of the selective NOP receptor agonist NNC 63-0532 promoted the opposite effect. These results demonstrate that opioid pathways and orphanin-mediated mechanisms have a critical role in modulating the activity of nigrotectal GABAergic pathways during the organisation of defensive behaviours.

Analysis of the 5-HT receptor in rabbit saphenous vein exemplifies the problems of using exclusion criteria for receptor classification.

Science.gov (United States)

Martin, G R; MacLennan, S J

1990-08-01

5-Hydroxytryptamine (5-HT) contracts ring preparations of rabbit saphenous vein via direct and indirect components, the latter being compatible with a "tyramine-like" action at sympathetic nerve terminals. Here an attempt was made to establish the identity of the receptor mediating contraction directly, in terms of the currently accepted proposals (Bradley et al. 1986). Results with agonists suggested 5-HT1-like receptor activation: methylsergide behaved as a partial agonist with microcolar affinity and 5-HT effects were mimicked by 5-carboxamidotryptamine (5-CT) and GR43175. The agonist potency order was 5-CT greater than 5-HT greater than methysergide greater than or equal to GR43175, the same as that reported at the 5-HT1-like receptor in dog saphenous vein (Feniuk et al. 1985; Humphrey et al. 1988). Consistent with this, 5-HT effects were resistant to blockade by the selective 5-HT3 receptor antagonist MDL72222 (1.0 mumol/l). In contrast, methiothepin (0.01-0.3 mumol/l), ketanserin (0.3-30.0 mumol/l) and spiperone (0.3-30.0 mumol/l) each produced surmountable antagonism which, although competitive in nature only for methiothepin (pKB = 9.45 +/- 0.09, 17 d.f.), implied 5-HT2 receptor involvement. The possibility that these discrepancies resulted from mixed populations of 5-HT1-like and 5-HT2 receptors can be excluded because; 1). Ketanserin and spiperone blocked the actions of 5-HT and the selective 5-HT1-like receptor agonist GR43175 with equal facility and 2). Responses to all of the agonists studied were similarly antagonised by flesinoxan (pKB approximately 6.4), a simple competitive antagonist at the receptor in rabbit saphenous vein.(ABSTRACT TRUNCATED AT 250 WORDS)

Costimulatory signal blockade in murine relapsing experimental autoimmune encephalomyelitis

DEFF Research Database (Denmark)

Schaub, M; Issazadeh-Navikas, Shohreh; Stadlbauer, T H

1999-01-01

Blockade of the CD28-B7 or CD40L-CD40 T cell costimulatory signals prevents induction of experimental autoimmune encephalomyelitis (EAE). However, the effect of simultaneous blockade of these signals in EAE is unknown. We show that administration of either MR1 (to block CD40L) or CTLA4Ig (to block...... B7) after immunization or after the first attack protects from EAE. Treatment with a combination of CTLA4Ig and MR1 provides additive protection, and is associated with complete absence of mononuclear cell infiltrates in the central nervous system, and marked suppression of proliferation of primed T...... cells in the periphery. Selective B7-1 blockade did not protect from EAE. These observations have implications for therapy of autoimmune diseases....

Chronic blockade of angiotensin II action prevents glomerulosclerosis, but induces graft vasculopathy in experimental kidney transplantation

NARCIS (Netherlands)

Smit-van Oosten, A; Navis, G; Stegeman, CA; Joles, JA; Klok, PA; Kuipers, F; Tiebosch, ATMG; van Goor, H

Long-term renin-angiotensin system blockade is beneficial in a variety of renal diseases, This study examines the long-term (34 weeks) effects of the angiotensin-converting enzyme inhibitor lisinopril and the angiotensin II receptor type I blocker L158,809 in the Fisher to Lewis rat model of chronic

Benzodiazepine receptor equilibrium constants for flumazenil and midazolam determined in humans with the single photon emission computer tomography tracer [123I]iomazenil

DEFF Research Database (Denmark)

Videbaek, C; Friberg, L; Holm, S

1993-01-01

twice, once without receptor blockade and once with a constant degree of partial blockade of the benzodiazepine receptors by infusion of nonradioactive flumazenil (Lanexat) or midazolam (Dormicum). Single photon emission computer tomography and blood sampling were performed intermittently for 6 h after...

TRPV1 receptor-mediated expression of Toll-like receptors 2 and 4 following permanent middle cerebral artery occlusion in rats

Science.gov (United States)

Hakimizadeh, Elham; Shamsizadeh, Ali; Roohbakhsh, Ali; Arababadi, Mohammad Kazemi; Hajizadeh, Mohammad Reza; Shariati, Mehdi; Fatemi, Iman; Moghadam-ahmadi, Amir; Bazmandegan, Gholamreza; Rezazadeh, Hossein; Allahtavakoli, Mohammad

2017-01-01

Objective(s): Stroke is known as a main cause of mortality and prolonged disability in adults. Both transient receptor potential V1 (TRPV1) channels and toll-like receptors (TLRs) are involved in mediating the inflammatory responses. In the present study, the effects of TRPV1 receptor activation and blockade on stroke outcome and gene expression of TLR2 and TLR4 were assessed following permanent middle cerebral artery occlusion in rats Materials and Methods: Eighty male Wistar rats were divided into four groups as follows: sham, vehicle, AMG9810 (TRPV1 antagonist) -treated and capsaicin (TRPV1 agonist) -treated. For Stroke induction, the middle cerebral artery was permanently occluded and then behavioral functions were evaluated 1, 3 and 7 days after stroke. Results: TRPV1 antagonism significantly reduced the infarct volume compared to the stroke group. Also, neurological deficits were decreased by AMG9810 seven days after cerebral ischemia. In the ledged beam-walking test, the slip ratio was enhanced following ischemia. AMG9810 decreased this index in stroke animals. However, capsaicin improved the ratio 3 and 7 days after cerebral ischemia. Compared to the sham group, the mRNA expression of TLR2 and TLR4 was significantly increased in the stroke rats. AMG9810 Administration significantly reduced the mRNA expression of TLR2 and TLR4. However, capsaicin did not significantly affect the gene expression of TLR2 and TLR4. Conclusion: Our results demonstrated that TRPV1 antagonism by AMG9810 attenuates behavioral function and mRNA expression of TLR2 and TLR4. Thus, it might be useful to shed light on future therapeutic strategies for the treatment of ischemic stroke. PMID:29085577

Dynamic 123I-BMIPP single-photon emission computed tomography in patients with congestive heart failure: effect of angiotensin II type-1 receptor blockade.

Science.gov (United States)

Takeishi, Yasuchika; Minamihaba, Osamu; Yamauchi, Sou; Arimoto, Takanori; Hirono, Osamu; Takahashi, Hiroki; Akiyama, Hideyuki; Miyamoto, Takuya; Nitobe, Joji; Nozaki, Naoki; Tachibana, Hidetada; Okuyama, Masaki; Fukui, Akio; Kubota, Isao; Okada, Akio; Takahashi, Kazuei

2004-04-01

Heart failure is a major and growing public health problem with a high mortality rate. Although recent studies have demonstrated that a variety of metabolic and/or neurohumoral factors are involved in the progression of this syndrome, the precise mechanisms responsible for this complex condition are poorly understood. To examine 123I-beta-methyl-iodophenylpentadecanoic acid (BMIPP) kinetics in the early phase soon after tracer injection in patients with congestive heart failure (CHF), we performed dynamic single-photon emission computed tomography (SPECT). Twenty-six patients with CHF and eight control subjects were examined. The consecutive 15 images of 2-min dynamic SPECT were acquired for 30 min after injection. In the early phase after injection (0-4 min), a significant amount of radioactivity existed in the blood pool. After 6 min, the myocardial 123I-BMIPP image was clear and thus the washout rate of 123I-BMIPP from 6 to 30 min was calculated. The washout rate of 123I-BMIPP from the myocardium was faster in patients with CHF than in the controls (8 +/- 4 vs. -5 +/- 3%, p acid metabolism may represent a new mechanism for beneficial effects of angiotensin II receptor blockade on cardiac function and survival in patients with heart failure. 123I-BMIPP washout in the early phase obtained from dynamic SPECT may be a new marker for evaluating the severity of heart failure and the effects of medical treatment.

Blockade of α2-adrenergic receptors in prelimbic cortex: impact on cocaine self-administration in adult spontaneously hypertensive rats following adolescent atomoxetine treatment.

Science.gov (United States)

Baskin, Britahny M; Nic Dhonnchadha, Bríd Á; Dwoskin, Linda P; Kantak, Kathleen M

2017-10-01

Research with the spontaneously hypertensive rat (SHR) model of attention deficit/hyperactivity disorder demonstrated that chronic methylphenidate treatment during adolescence increased cocaine self-administration established during adulthood under a progressive ratio (PR) schedule. Compared to vehicle, chronic atomoxetine treatment during adolescence failed to increase cocaine self-administration under a PR schedule in adult SHR. We determined if enhanced noradrenergic transmission at α2-adrenergic receptors within prefrontal cortex contributes to this neutral effect of adolescent atomoxetine treatment in adult SHR. Following treatment from postnatal days 28-55 with atomoxetine (0.3 mg/kg) or vehicle, adult male SHR and control rats from Wistar-Kyoto (WKY) and Wistar (WIS) strains were trained to self-administer 0.3 mg/kg cocaine. Self-administration performance was evaluated under a PR schedule of cocaine delivery following infusion of the α2-adrenergic receptor antagonist idazoxan (0 and 10-56 μg/side) directly into prelimbic cortex. Adult SHR attained higher PR break points and had greater numbers of active lever responses and infusions than WKY and WIS. Idazoxan dose-dependently increased PR break points and active lever responses in SHR following adolescent atomoxetine vs. vehicle treatment. Behavioral changes were negligible after idazoxan pretreatment in SHR following adolescent vehicle or in WKY and WIS following adolescent atomoxetine or vehicle. α2-Adrenergic receptor blockade in prelimbic cortex of SHR masked the expected neutral effect of adolescent atomoxetine on adult cocaine self-administration behavior. Moreover, greater efficacy of acute idazoxan challenge in adult SHR after adolescent atomoxetine relative to vehicle is consistent with the idea that chronic atomoxetine may downregulate presynaptic α2A-adrenergic autoreceptors in SHR.

Blockade and enhancement of glutamate receptor responses in Xenopus oocytes by methylated arsenicals

Energy Technology Data Exchange (ETDEWEB)

Krueger, Katharina; Gruner, Janina; Madeja, Michael; Musshoff, Ulrich [Universitaetsklinikum Muenster, Institut fuer Physiologie I, Muenster (Germany); Hartmann, Louise M.; Hirner, Alfred V. [Universitaet Duisburg-Essen, Institut fuer Umweltanalytik, Essen (Germany); Binding, Norbert [Universitaetsklinikum Muenster, Institut fuer Arbeitsmedizin, Muenster (Germany)

2006-08-15

Pentavalent and trivalent organoarsenic compounds belong to the major metabolites of inorganic arsenicals detected in humans. Recently, the question was raised whether the organic arsenicals represent metabolites of a detoxification process or methylated species with deleterious biological effects. In this study, the effects of trivalent arsenite (AsO{sub 3} {sup 3-}; iA{sup III}), the pentavalent organoarsenic compounds monomethylarsonic acid (CH{sub 3}AsO(OH){sub 2}; MMA{sup V}) and dimethylarsinic acid ((CH{sub 3}){sub 2}AsO(OH); DMA{sup V}) and the trivalent compounds monomethylarsonous acid (CH{sub 3}As(OH){sub 2}, MMA{sup III}) and dimethylarsinous acid ((CH{sub 3}){sub 2}As(OH); DMA{sup III}) were tested on glutamate receptors and on voltage-operated potassium and sodium channels heterologously expressed in Xenopus oocytes. Membrane currents of ion channels were measured by conventional two-electrode voltage-clamp techniques. The effects of arsenite were tested in concentrations of 1-1,000 {mu}mol/l and the organic arsenical compounds were tested in concentrations of 0.1-100 {mu}mol/l. We found no significant effects on voltage-operated ion channels; however, the arsenicals exert different effects on glutamate receptors. While MMA{sup V} and MMA{sup III} significantly enhanced ion currents through N-methyl-d-aspartate (NMDA) receptor ion channels with threshold concentrations <10 {mu}mol/l, DMA{sup V} and DMA{sup III} significantly reduced NMDA-receptor mediated responses with threshold concentrations <0.1 {mu}mol/l; iA{sup III} had no effects on glutamate receptors of the NMDA type. MMA{sup III} and DMA{sup V} significantly reduced ion currents through {alpha}-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA)-receptor ion channels with threshold concentrations <10 {mu}mol/l (MMA{sup III}) and <1 {mu}mol/l (DMA{sup V}). MMA{sup V} and iA{sup III} had no significant effects on glutamate receptors of the AMPA type. The effects of MMA{sup V}, MMA

Checkpoint blockade in combination with cancer vaccines.

Science.gov (United States)

Morse, Michael A; Lyerly, H Kim

2015-12-16

Checkpoint blockade, prevention of inhibitory signaling that limits activation or function of tumor antigen-specific T cells responses, is revolutionizing the treatment of many poor prognosis malignancies. Indeed monoclonal antibodies that modulate signaling through the inhibitory molecules CTLA-4 and PD-1 are now clinically available; however, many tumors, demonstrate minimal response suggesting the need for combinations with other therapeutic strategies. Because an inadequate frequency of activated tumor antigen-specific T cells in the tumor environment, the so-called non-inflamed phenotype, is observed in some malignancies, other rationale partners are modalities that lead to enhanced T cell activation (vaccines, cytokines, toll-like receptor agonists, and other anticancer therapies such as chemo-, radio- or targeted therapies that lead to release of antigen from tumors). This review will focus on preclinical and clinical data supporting the use of cancer vaccines with anti-CTLA-4 and anti-PD-1/PD-L1 antibodies. Preliminary preclinical data demonstrate enhanced antitumor activity although the results in human studies are less clear. Broader combinations of multiple immune modulators are now under study. Copyright © 2015 Elsevier Ltd. All rights reserved.

Repeated blockade of mineralocorticoid receptors, but not of glucocorticoid receptors impairs food rewarded spatial learning

NARCIS (Netherlands)

Douma, B. R.; Korte, S. M.; Buwalda, B.; La Fleur, S. E.; Bohus, B.; Luiten, P. G.

1998-01-01

Corticosteroids from the adrenal cortex influence a variety of behaviours including cognition, learning and memory. These hormones act via two intracellular receptors, the mineralo-corticoid receptor (MR) and the glucocorticoid receptor (GR). These two receptor types display a high concentration and

Repeated blockade of mineralocorticoid receptors, but not of glucocorticoid receptors impairs food rewarded spatial learning

NARCIS (Netherlands)

Douma, BRK; Korte, SM; Buwalda, B; la Fleur, SE; Bohus, B; Luiten, PGM

Corticosteroids from the adrenal cortex influence a variety of behaviours including cognition, learning and memory. These hormones act via two intracellular receptors, the mineralo-corticoid receptor (MR) and the glucocorticoid receptor (GR). These two receptor types display a high concentration and

Peripheral substance P and neurokinin-1 receptors have a role in inflammatory and neuropathic orofacial pain models.

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Teodoro, Fernanda C; Tronco Júnior, Marcos F; Zampronio, Aleksander R; Martini, Alessandra C; Rae, Giles A; Chichorro, Juliana G

2013-06-01

There is accumulating evidence that substance P released from peripheral sensory neurons participates in inflammatory and neuropathic pain. In this study it was investigated the ability of substance P to induce orofacial nociception and thermal and mechanical hyperalgesia, as well as the role of NK1 receptors on models of orofacial inflammatory and neuropathic pain. Substance P injected into the upper lip at 1, 10 and 100 μg/50 μL failed to induce nociceptive behavior. Also, substance P (0.1-10 μg/50 μL) injected into the upper lip did not evoke orofacial cold hyperalgesia and when injected at 1 μg/50 μL did not induce mechanical hyperalgesia. However, substance P at this latter dose induced orofacial heat hyperalgesia, which was reduced by the pre-treatment of rats with a non-peptide NK1 receptor antagonist (SR140333B, 3mg/kg). Systemic treatment with SR140333B (3 mg/kg) also reduced carrageenan-induced heat hyperalgesia, but did not exert any influence on carrageenan-induced cold hyperalgesia. Blockade of NK1 receptors with SR140333B also reduced by about 50% both phases of the formalin response evaluated in the orofacial region. Moreover, heat, but not cold or mechanical, hyperalgesia induced by constriction of the infraorbital nerve, a model of trigeminal neuropathic pain, was abolished by pretreatment with SR140333B. Considering that substance P was peripherally injected (i.e. upper lip) and the NK1 antagonist used lacks the ability to cross the blood-brain-barrier, our results demonstrate that the peripheral SP/NK1 system participates in the heat hyperalgesia associated with inflammation or nerve injury and in the persistent pain evoked by formalin in the orofacial region. Copyright © 2012 Elsevier Ltd. All rights reserved.

Coulomb Blockade Plasmonic Switch.

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Xiang, Dao; Wu, Jian; Gordon, Reuven

2017-04-12

Tunnel resistance can be modulated with bias via the Coulomb blockade effect, which gives a highly nonlinear response current. Here we investigate the optical response of a metal-insulator-nanoparticle-insulator-metal structure and show switching of a plasmonic gap from insulator to conductor via Coulomb blockade. By introducing a sufficiently large charging energy in the tunnelling gap, the Coulomb blockade allows for a conductor (tunneling) to insulator (capacitor) transition. The tunnelling electrons can be delocalized over the nanocapacitor again when a high energy penalty is added with bias. We demonstrate that this has a huge impact on the plasmonic resonance of a 0.51 nm tunneling gap with ∼70% change in normalized optical loss. Because this structure has a tiny capacitance, there is potential to harness the effect for high-speed switching.

TGFβ activated kinase 1 (TAK1 at the crossroad of B cell receptor and Toll-like receptor 9 signaling pathways in human B cells.

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Dániel Szili

Full Text Available B cell development and activation are regulated by combined signals mediated by the B cell receptor (BCR, receptors for the B-cell activating factor of the tumor necrosis factor family (BAFF-R and the innate receptor, Toll-like receptor 9 (TLR9. However, the underlying mechanisms by which these signals cooperate in human B cells remain unclear. Our aim was to elucidate the key signaling molecules at the crossroads of BCR, BAFF-R and TLR9 mediated pathways and to follow the functional consequences of costimulation.Therefore we stimulated purified human B cells by combinations of anti-Ig, B-cell activating factor of the tumor necrosis factor family (BAFF and the TLR9 agonist, CpG oligodeoxynucleotide. Phosphorylation status of various signaling molecules, B cell proliferation, cytokine secretion, plasma blast generation and the frequency of IgG producing cells were investigated. We have found that BCR induced signals cooperate with BAFF-R- and TLR9-mediated signals at different levels of cell activation. BCR and BAFF- as well as TLR9 and BAFF-mediated signals cooperate at NFκB activation, while BCR and TLR9 synergistically costimulate mitogen activated protein kinases (MAPKs, ERK, JNK and p38. We show here for the first time that the MAP3K7 (TGF beta activated kinase, TAK1 is responsible for the synergistic costimulation of B cells by BCR and TLR9, resulting in an enhanced cell proliferation, plasma blast generation, cytokine and antibody production. Specific inhibitor of TAK1 as well as knocking down TAK1 by siRNA abrogates the synergistic signals. We conclude that TAK1 is a key regulator of receptor crosstalk between BCR and TLR9, thus plays a critical role in B cell development and activation.

On the role of subtype selective adenosine receptor agonists during proliferation and osteogenic differentiation of human primary bone marrow stromal cells.

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Costa, M Adelina; Barbosa, A; Neto, E; Sá-e-Sousa, A; Freitas, R; Neves, J M; Magalhães-Cardoso, T; Ferreirinha, F; Correia-de-Sá, P

2011-05-01

Purines are important modulators of bone cell biology. ATP is metabolized into adenosine by human primary osteoblast cells (HPOC); due to very low activity of adenosine deaminase, the nucleoside is the end product of the ecto-nucleotidase cascade. We, therefore, investigated the expression and function of adenosine receptor subtypes (A(1) , A(2A) , A(2B) , and A(3) ) during proliferation and osteogenic differentiation of HPOC. Adenosine A(1) (CPA), A(2A) (CGS21680C), A(2B) (NECA), and A(3) (2-Cl-IB-MECA) receptor agonists concentration-dependently increased HPOC proliferation. Agonist-induced HPOC proliferation was prevented by their selective antagonists, DPCPX, SCH442416, PSB603, and MRS1191. CPA and NECA facilitated osteogenic differentiation measured by increases in alkaline phosphatase (ALP) activity. This contrasts with the effect of CGS21680C which delayed HPOC differentiation; 2-Cl-IB-MECA was devoid of effect. Blockade of the A(2B) receptor with PSB603 prevented osteogenic differentiation by NECA. In the presence of the A(1) antagonist, DPCPX, CPA reduced ALP activity at 21 and 28 days in culture. At the same time points, blockade of A(2A) receptors with SCH442416 transformed the inhibitory effect of CGS21680C into facilitation. Inhibition of adenosine uptake with dipyridamole caused a net increase in osteogenic differentiation. The presence of all subtypes of adenosine receptors on HPOC was confirmed by immunocytochemistry. Data show that adenosine is an important regulator of osteogenic cell differentiation through the activation of subtype-specific receptors. The most abundant A(2B) receptor seems to have a consistent role in cell differentiation, which may be balanced through the relative strengths of A(1) or A(2A) receptors determining whether osteoblasts are driven into proliferation or differentiation. Copyright © 2010 Wiley-Liss, Inc.

Expression of PD-L1 on canine tumor cells and enhancement of IFN-γ production from tumor-infiltrating cells by PD-L1 blockade.

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Naoya Maekawa

Full Text Available Programmed death 1 (PD-1, an immunoinhibitory receptor, and programmed death ligand 1 (PD-L1, its ligand, together induce the "exhausted" status in antigen-specific lymphocytes and are thus involved in the immune evasion of tumor cells. In this study, canine PD-1 and PD-L1 were molecularly characterized, and their potential as therapeutic targets for canine tumors was discussed. The canine PD-1 and PD-L1 genes were conserved among canine breeds. Based on the sequence information obtained, the recombinant canine PD-1 and PD-L1 proteins were constructed; they were confirmed to bind each other. Antibovine PD-L1 monoclonal antibody effectively blocked the binding of recombinant PD-1 with PD-L1-expressing cells in a dose-dependent manner. Canine melanoma, mastocytoma, renal cell carcinoma, and other types of tumors examined expressed PD-L1, whereas some did not. Interestingly, anti-PD-L1 antibody treatment enhanced IFN-γ production from tumor-infiltrating cells. These results showed that the canine PD-1/PD-L1 pathway is also associated with T-cell exhaustion in canine tumors and that its blockade with antibody could be a new therapeutic strategy for canine tumors. Further investigations are needed to confirm the ability of anti-PD-L1 antibody to reactivate canine antitumor immunity in vivo, and its therapeutic potential has to be further discussed.

γ1-Containing GABA-A Receptors Cluster at Synapses Where they Mediate Slower Synaptic Currents than γ2-Containing GABA-A Receptors

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Christine L. Dixon

2017-06-01

Full Text Available GABA-A receptors (GABAARs are pentameric ligand-gated ion channels that are assembled mainly from α (α1–6, β (β1–3 and γ (γ1–3 subunits. Although GABAARs containing γ2L subunits mediate most of the inhibitory neurotransmission in the brain, significant expression of γ1 subunits is seen in the amygdala, pallidum and substantia nigra. However, the location and function of γ1-containing GABAARs in these regions remains unclear. In “artificial” synapses, where the subunit composition of postsynaptic receptors is specifically controlled, γ1 incorporation slows the synaptic current decay rate without affecting channel deactivation, suggesting that γ1-containing receptors are not clustered and therefore activated by diffuse neurotransmitter. However, we show that γ1-containing receptors are localized at neuronal synapses and form clusters in both synaptic and extrasynaptic regions. In addition, they exhibit rapid membrane diffusion and a higher frequency of exchange between synaptic and perisynaptic populations compared to γ2L-containing GABAARs. A point mutation in the large intracellular domain and a pharmacological analysis reveal that when a single non-conserved γ2L residue is mutated to its γ1 counterpart (T349L, the synaptic current decay is slowed from γ2L- to γ1-like without changing the clustering or diffusion properties of the receptors. In addition, previous fast perfusion and single channel kinetic experiments revealed no difference in the intrinsic closing rates of γ2L- and γ1-containing receptors when expressed in HEK293 cells. These observations together with Monte Carlo simulations of synaptic function confirm that decreased clustering does not control γ1-containing GABAAR kinetics. Rather, they suggest that γ1- and γ2L-containing receptors exhibit differential synaptic current decay rates due to differential gating dynamics when localized at the synapse.

Positron emission tomography study of pindolol occupancy of 5-HT{sub 1A} receptors in humans: preliminary analyses

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Martinez, Diana; Mawlawi, Osama; Hwang, Dah-Ren; Kent, Justine; Simpson, Norman; Parsey, Ramin V.; Hashimoto, Tomoki; Slifstein, Mark; Huang Yiyun; Heertum, Ronald van; Abi-Dargham, Anissa; Caltabiano, Stephen; Malizia, Andrea; Cowley, Hugh; Mann, J. John; Laruelle, Marc

2000-07-01

Preclinical studies in rodents suggest that augmentation of serotonin reuptake inhibitors (SSRIs) therapy by the 5-hydroxytryptamine{sub 1A} (5-HT{sub 1A}) receptor agent pindolol might reduce the delay between initiation of treatment and antidepressant response. This hypothesis is based on the ability of pindolol to potentiate the increase in serotonin (5-HT) transmission induced by SSRIs, an effect achieved by blockade of the 5-HT{sub 1A} autoreceptors in the dorsal raphe nuclei (DRN). However, placebo-controlled clinical studies of pindolol augmentation of antidepressant therapy have reported inconsistent results. Here, we evaluated the occupancy of 5-HT{sub 1A} receptors following treatment with controlled release pindolol in nine healthy volunteers with positron-emission tomography (PET). Each subject was studied four times: at baseline (scan 1), following 1 week of oral administration of pindolol CR (7.5 mg/day) at peak level, 4 h after the dose (scan 2), and at 10 h following the dose (scan 3), and following one dose of pindolol CR (30 mg) (at peak level, 4 h) (scan 4). Pindolol occupancy of 5-HT{sub 1A} receptors was evaluated in the DRN and cortical regions as the decrease in binding potential (BP) of the radiolabelled selective 5-HT{sub 1A} antagonist [carbonyl-{sup 11}C]WAY-100635 or [carbonyl-{sup 11}C] N-(2-(4-(2-methoxyphenyl)-1-piperazinyl)ethyl)-N-(2-pyridyl) cyclohexanecarboxamide abbreviated as [{sup 11}C]WAY-100635. Pindolol dose-dependently decreased [{sup 11}C]WAY-100635 BP. Combining all the regions, occupancy was 20 {+-} 8% at scan 2, 14 {+-} 8% at scan 3, and 44 {+-} 8% at scan 4. The results of this study suggest that at doses used in clinical studies of augmentation of the SSRI effect by pindolol (2.5 mg t.i.d.), the occupancy of 5-HT{sub 1A} receptors is moderate and highly variable between subjects. This factor might explain the variable results obtained in clinical studies. On the other hand, at each dose tested, pindolol occupancy of 5

Blockade of A2b Adenosine Receptor Reduces Tumor Growth and Immune Suppression Mediated by Myeloid-Derived Suppressor Cells in a Mouse Model of Melanoma

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Raffaella Iannone

2013-12-01

Full Text Available The A2b receptor (A2bR belongs to the adenosine receptor family. Emerging evidence suggest that A2bR is implicated in tumor progression in some murine tumor models, but the therapeutic potential of targeting A2bR in melanoma has not been examined. This study first shows that melanoma-bearing mice treated with Bay 60-6583, a selective A2bR agonist, had increased melanoma growth. This effect was associated with higher levels of immune regulatory mediators interleukin-10 (IL-10 and monocyte chemoattractant protein 1 (MCP-1 and accumulation of tumor-associated CD11b positive Gr1 positive cells (CD11b+Gr1+ myeloid-derived suppressor cells (MDSCs. Depletion of CD11b+Gr1+ cells completely reversed the protumor activity of Bay 60-6583. Conversely, pharmacological blockade of A2bR with PSB1115 reversed immune suppression in the tumor microenvironment, leading to a significant melanoma growth delay. PSB1115 treatment reduced both levels of IL-10 and MCP-1 and CD11b+Gr1+ cell number in melanoma lesions. These effects were associated with higher frequency of tumor-infiltrating CD8 positive (CD8+ T cells and natural killer T (NKT cells and increased levels of T helper 1 (Th1-like cytokines. Adoptive transfer of CD11b+Gr1+ cells abrogated the antitumor activity of PSB1115. These data suggest that the antitumor activity of PSB1115 relies on its ability to lower accumulation of tumor-infiltrating MDSCs and restore an efficient antitumor T cell response. The antitumor effect of PSB1115 was not observed in melanoma-bearing nude mice. Furthermore, PSB1115 enhanced the antitumor efficacy of dacarbazine. These data indicate that A2bR antagonists such as PSB1115 should be investigated as adjuvants in the treatment of melanoma.

Vasopressin V1a receptors are present in the carotid body and contribute to the control of breathing in male Sprague-Dawley rats.

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Żera, Tymoteusz; Przybylski, Jacek; Grygorowicz, Tomasz; Kasarełło, Kaja; Podobińska, Martyna; Mirowska-Guzel, Dagmara; Cudnoch-Jędrzejewska, Agnieszka

2018-04-01

Vasopressin (AVP) maintains body homeostasis by regulating water balance, cardiovascular system and stress response. AVP inhibits breathing through central vasopressin 1a receptors (V1aRs). Chemoreceptors within carotid bodies (CBs) detect chemical and hormonal signals in the bloodstream and provide sensory input to respiratory and cardiovascular centers of the brainstem. In the study we investigated if CBs contain V1aRs and how the receptors are involved in the regulation of ventilation by AVP. We first immunostained CBs for V1aRs and tyrosine hydroxylase, a marker of chemoreceptor type I (glomus) cells. In urethane-anesthetized adult Sprague-Dawley male rats, we then measured hemodynamic and respiratory responses to systemic (intravenous) or local (carotid artery) administration of AVP prior and after systemic blockade of V1aRs. Immunostaining of CBs showed colocalization of V1aRs and tyrosine hydroxylase within glomus cells. Systemic administration of AVP increased mean arterial blood pressure (MABP) and decreased respiratory rate (RR) and minute ventilation (MV). Local administration of AVP increased MV and RR without significant changes in MABP or heart rate. Pretreatment with V1aR antagonist abolished responses to local and intravenous AVP administration. Our findings show that chemosensory cells within CBs express V1aRs and that local stimulation of the CB with AVP increases ventilation, which is contrary to systemic effects of AVP manifested by decreased ventilation. The responses are mediated by V1aRs, as blockade of the receptors prevents changes in ventilation. We hypothesize that excitatory effects of AVP within the CB provide a counterbalancing mechanism for the inhibitory effects of systemically acting AVP on the respiration. Copyright © 2018 Elsevier Inc. All rights reserved.

Inverse agonist and neutral antagonist actions of synthetic compounds at an insect 5-HT1 receptor.

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Troppmann, B; Balfanz, S; Baumann, A; Blenau, W

2010-04-01

5-Hydroxytryptamine (5-HT) has been shown to control and modulate many physiological and behavioural functions in insects. In this study, we report the cloning and pharmacological properties of a 5-HT(1) receptor of an insect model for neurobiology, physiology and pharmacology. A cDNA encoding for the Periplaneta americana 5-HT(1) receptor was amplified from brain cDNA. The receptor was stably expressed in HEK 293 cells, and the functional and pharmacological properties were determined in cAMP assays. Receptor distribution was investigated by RT-PCR and by immunocytochemistry using an affinity-purified polyclonal antiserum. The P. americana 5-HT(1) receptor (Pea5-HT(1)) shares pronounced sequence and functional similarity with mammalian 5-HT(1) receptors. Activation with 5-HT reduced adenylyl cyclase activity in a dose-dependent manner. Pea5-HT(1) was expressed as a constitutively active receptor with methiothepin acting as a neutral antagonist, and WAY 100635 as an inverse agonist. Receptor mRNA was present in various tissues including brain, salivary glands and midgut. Receptor-specific antibodies showed that the native protein was expressed in a glycosylated form in membrane samples of brain and salivary glands. This study marks the first pharmacological identification of an inverse agonist and a neutral antagonist at an insect 5-HT(1) receptor. The results presented here should facilitate further analyses of 5-HT(1) receptors in mediating central and peripheral effects of 5-HT in insects.

From Napoleon To Netanyahu: Blockading Through Two Centuries

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2016-04-01

Hemisphere. With a range of only 2,500 miles per load of coal, steam powered ships could not reach Europe without refueling. Blockading actions at Vera ...BIBLIOGRAPHY Calore, Paul. Naval Campaigns of the Civil War. Jefferson, NC: McFarland and Co., 2003. Davis, Lance E . and Stanley L...Lance E . Davis and Stanley L. Engerman, Naval Blockades in Peace and War: An Economic History Since 1750

Neuropeptide Y2 receptors in anteroventral BNST control remote fear memory depending on extinction training.

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Verma, Dilip; Tasan, Ramon; Sperk, Guenther; Pape, Hans-Christian

2018-03-01

The anterior bed nucleus of stria terminalis (BNST) is involved in reinstatement of extinguished fear, and neuropeptide Y2 receptors influence local synaptic signaling. Therefore, we hypothesized that Y2 receptors in anteroventral BNST (BNSTav) interfere with remote fear memory and that previous fear extinction is an important variable. C57BL/6NCrl mice were fear-conditioned, and a Y2 receptor-specific agonist (NPY 3-36 ) or antagonist (JNJ-5207787) was applied in BNSTav before fear retrieval at the following day. Remote fear memory was tested on day 16 in two groups of mice, which had (experiment 1) or had not (experiment 2) undergone extinction training after conditioning. In the group with extinction training, tests of remote fear memory revealed partial retrieval of extinction, which was prevented after blockade of Y2 receptors in BNSTav. No such effect was observed in the group with no extinction training, but stimulation of Y2 receptors in BNSTav mimicked the influence of extinction during tests of remote fear memory. Pharmacological manipulation of Y2 receptors in BNSTav before fear acquisition (experiment 3) had no effect on fear memory retrieval, extinction or remote fear memory. Furthermore, partial retrieval of extinction during tests of remote fear memory was associated with changes in number of c-Fos expressing neurons in BNSTav, which was prevented or mimicked upon Y2 blockade or stimulation in BNSTav. These results indicate that Y2 receptor manipulation in BNSTav interferes with fear memory and extinction retrieval at remote stages, likely through controlling neuronal activity in BNSTav during extinction training. Copyright © 2018 Elsevier Inc. All rights reserved.

Pituitary adenylate cyclase 1 receptor internalization and endosomal signaling mediate the pituitary adenylate cyclase activating polypeptide-induced increase in guinea pig cardiac neuron excitability.

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Merriam, Laura A; Baran, Caitlin N; Girard, Beatrice M; Hardwick, Jean C; May, Victor; Parsons, Rodney L

2013-03-06

After G-protein-coupled receptor activation and signaling at the plasma membrane, the receptor complex is often rapidly internalized via endocytic vesicles for trafficking into various intracellular compartments and pathways. The formation of signaling endosomes is recognized as a mechanism that produces sustained intracellular signals that may be distinct from those generated at the cell surface for cellular responses including growth, differentiation, and survival. Pituitary adenylate cyclase activating polypeptide (PACAP; Adcyap1) is a potent neurotransmitter/neurotrophic peptide and mediates its diverse cellular functions in part through internalization of its cognate G-protein-coupled PAC1 receptor (PAC1R; Adcyap1r1). In the present study, we examined whether PAC1R endocytosis participates in the regulation of neuronal excitability. Although PACAP increased excitability in 90% of guinea pig cardiac neurons, pretreatment with Pitstop 2 or dynasore to inhibit clathrin and dynamin I/II, respectively, suppressed the PACAP effect. Subsequent addition of inhibitor after the PACAP-induced increase in excitability developed gradually attenuated excitability with no changes in action potential properties. Likewise, the PACAP-induced increase in excitability was markedly decreased at ambient temperature. Receptor trafficking studies with GFP-PAC1 cell lines demonstrated the efficacy of Pitstop 2, dynasore, and low temperatures at suppressing PAC1R endocytosis. In contrast, brefeldin A pretreatments to disrupt Golgi vesicle trafficking did not blunt the PACAP effect, and PACAP/PAC1R signaling still increased neuronal cAMP production even with endocytic blockade. Our results demonstrate that PACAP/PAC1R complex endocytosis is a key step for the PACAP modulation of cardiac neuron excitability.

Angiotensin II reduces cardiac AdipoR1 expression through AT1 receptor/ROS/ERK1/2/c-Myc pathway.

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Li Li

Full Text Available Adiponectin, an abundant adipose tissue-derived protein, exerts protective effect against cardiovascular disease. Adiponectin receptors (AdipoR1 and AdipoR2 mediate the beneficial effects of adiponectin on the cardiovascular system. However, the alteration of AdipoRs in cardiac remodeling is not fully elucidated. Here, we investigated the effect of angiotensin II (AngII on cardiac AdipoRs expression and explored the possible molecular mechanism. AngII infusion into rats induced cardiac hypertrophy, reduced AdipoR1 but not AdipoR2 expression, and attenuated the phosphorylations of adenosine monophosphate-activated protein kinase and acetyl coenzyme A carboxylase, and those effects were all reversed by losartan, an AngII type 1 (AT1 receptor blocker. AngII reduced expression of AdipoR1 mRNA and protein in cultured neonatal rat cardiomyocytes, which was abolished by losartan, but not by PD123319, an AT2 receptor antagonist. The antioxidants including reactive oxygen species (ROS scavenger NAC, NADPH oxidase inhibitor apocynin, Nox2 inhibitor peptide gp91 ds-tat, and mitochondrial electron transport chain complex I inhibitor rotenone attenuated AngII-induced production of ROS and phosphorylation of extracellular signal-regulated kinase (ERK 1/2. AngII-reduced AdipoR1 expression was reversed by pretreatment with NAC, apocynin, gp91 ds-tat, rotenone, and an ERK1/2 inhibitor PD98059. Chromatin immunoprecipitation assay demonstrated that AngII provoked the recruitment of c-Myc onto the promoter region of AdipoR1, which was attenuated by PD98059. Moreover, AngII-induced DNA binding activity of c-Myc was inhibited by losartan, NAC, apocynin, gp91 ds-tat, rotenone, and PD98059. c-Myc small interfering RNA abolished the inhibitory effect of AngII on AdipoR1 expression. Our results suggest that AngII inhibits cardiac AdipoR1 expression in vivo and in vitro and AT1 receptor/ROS/ERK1/2/c-Myc pathway is required for the downregulation of AdipoR1 induced by AngII.

Autocrine CSF-1 and CSF-1 Receptor Co-expression Promotes Renal Cell Carcinoma Growth