Adenosine A1 receptor-mediated inhibition of in vitro prolactin secretion from the rat anterior pituitary

In previous studies, we demonstrated biphasic purinergic effects on prolactin (PRL) secretion stimulated by an adenosine A₂ agonist. In the present study, we investigated the role of the activation of adenosine A₁ receptors by (R)-N6-(2-phenylisopropyl)adenosine (R-PIA) at the pituitary level in in vitro PRL secretion. Hemipituitaries (one per cuvette in five replicates) from adult male rats were incubated. Administration of R-PIA (0.001, 0.01, 0.1, 1, and 10 µM) induced a reduction of PRL secretion into the medium in a U-shaped dose-response curve. The maximal reduction was obtained with 0.1 µM R-PIA (mean ± SEM, 36.01 ± 5.53 ng/mg tissue weight (t.w.)) treatment compared to control (264.56 ± 15.46 ng/mg t.w.). R-PIA inhibition (0.01 µM = 141.97 ± 15.79 vs control = 244.77 ± 13.79 ng/mg t.w.) of PRL release was blocked by 1 µM cyclopentyltheophylline, a specific A₁ receptor antagonist (1 µM = 212.360 ± 26.560 ng/mg t.w.), whereas cyclopentyltheophylline alone (0.01, 0.1, 1 µM) had no effect. R-PIA (0.001, 0.01, 0.1, 1 µM) produced inhibition of PRL secretion stimulated by both phospholipase C (0.5 IU/mL; 977.44 ± 76.17 ng/mg t.w.) and dibutyryl cAMP (1 mM; 415.93 ± 37.66 ng/mg t.w.) with nadir established at the dose of 0.1 µM (225.55 ± 71.42 and 201.9 ± 19.08 ng/mg t.w., respectively). Similarly, R-PIA (0.01 µM) decreased (242.00 ± 24.00 ng/mg t.w.) the PRL secretion stimulated by cholera toxin (0.5 mg/mL; 1050.00 ± 70.00 ng/mg t.w.). In contrast, R-PIA had no effect (468.00 ± 34.00 ng/mg t.w.) on PRL secretion stimulation by pertussis toxin (0.5 mg/mL; 430.00 ± 26.00 ng/mg t.w.). These results suggest that inhibition of PRL secretion after A₁ receptor activation by R-PIA is mediated by a Gi protein-dependent mechanism.

Estudo comparativo morfofuncional e expressão de receptor de melanocortina do tipo 1 em lesões de melasma

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Human neutrophils produce IL-12, IL-10, PGE2 and LTB4 in response to Paracoccidioides brasiliensis. Involvement of TLR2, mannose receptor and dectin-1

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Expression of Protease Activated Receptor-1 in Chronic Periodontitis

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Ação da IL-18 sobre a expressão do receptor dectina-1 e produção de citocinas por monócitos humanos desafiados com diferentes cepas de Paracoccidioides brasiliensis

Estudos têm demonstrado que o reconhecimento inicial de microrganismos é mediado por receptores celulares expressos em células da imunidade inata denominados receptores de reconhecimento de padrões (PRRs). Assim, a interação entre moléculas de superfície dos patógenos e receptores homólogos presentes na membrana celular de monócitos, modula a fagocitose, a ativação da célula e conseqüentemente a produção de citocinas. Trabalhos têm demonstrado a importância da estimulação de receptores toll-like 2 e 4 (TLR2 e TLR4), receptores de manose (MR) e dectina-1 de monócitos, tanto em infecções bacterianas como fúngicas, culminando com indução de produção de várias citocinas. A IL-18 é uma citocina indutora de IFN-g e possui uma ação extremamente importante, por ser capaz de promover tanto uma resposta do tipo Th1 ou Th2, dependendo do contexto de estimulação e do microambiente de citocinas. Em trabalho recente demonstramos que a IL-18 possui uma ação importante sobre o aumento da expressão de MR em monócitos humanos, e o reconhecimento do Paracoccidioides brasiliensis via esse receptor causaria aumento do crescimento fúngico no interior da célula. Dessa forma, os objetivos do presente projeto foram: 1) Avaliar a ação da IL- 18 sobre a expressão do receptor dectina-1 por monócitos humanos desafiados in vitro com diferentes cepas do P. brasiliensis; b) Avaliar a participação da dectina-1 na indução da produção de IL-18, TNF-a e IL-10 por monócitos desafiados in vitro com diferentes cepas do P. brasiliensis. Assim, monócitos de indivíduos normais tratados in vitro com IL-18 foram desafiados com diferentes de cepas do P. brasiliensis, e a expressão do receptor dectina-1 foi avaliada pela técnica de citometria de fluxo. A dosagem de IL-18, TNF-a e IL-10 no sobrenadante de cultura de monócitos desafiados com P. brasiliensis foi realizada utilizando a técnica de ELISA . Os resultados mostraram que a ...

Avaliação do envolvimento do receptor dectina-1 na atividade fungicida e na produção de metabólitos do oxigênio por neutrófilos e monócitos humanos desafiados com Paracoccidioides brasiliensis

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Apoptose relacionada à infecção in vitro por herpesvírus bovinos tipo 1 e 5

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

The orexin receptor 1 in the locus coeruleus modulates the hypercapnic ventilatory response in unanesthetized rats

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Association of apolipoprotein B and adiponectin receptor 1 genes with carcass, bone integrity and performance traits in a paternal broiler line

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Thrombin-Receptor Antagonist Vorapaxar in Acute Coronary Syndromes

BACKGROUND Vorapaxar is a new oral protease-activated receptor 1 (PAR-1) antagonist that inhibits thrombin-induced platelet activation. METHODS In this multinational, double-blind, randomized trial, we compared vorapaxar with placebo in 12,944 patients who had acute coronary syndromes without ST-segment elevation. The primary end point was a composite of death from cardiovascular causes, myocardial infarction, stroke, recurrent ischemia with rehospitalization, or urgent coronary revascularization. RESULTS Follow-up in the trial was terminated early after a safety review. After a median follow-up of 502 days (interquartile range, 349 to 667), the primary end point occurred in 1031 of 6473 patients receiving vorapaxar versus 1102 of 6471 patients receiving placebo (Kaplan-Meier 2-year rate, 18.5010 vs. 19.9%; hazard ratio, 0.92; 95% confidence interval [CI], 0.85 to 1.01; P=0.07). A composite of death from cardiovascular causes, myocardial infarction, or stroke occurred in 822 patients in the vorapaxar group versus 910 in the placebo group (14.7% and 16.4%, respectively; hazard ratio, 0.89; 95% CI, 0.81 to 0.98; P=0.02). Rates of moderate and severe bleeding were 7.2% in the vorapaxar group and 5.2% in the placebo group (hazard ratio, 1.35; 95% CI, 1.16 to 1.58; P<0.001). Intracranial hemorrhage rates were 1.1% and 0.2%, respectively (hazard ratio, 3.39; 95% CI, 1.78 to 6.45; P<0.001). Rates of nonhemorrhagic adverse events were similar in the two groups. CONCLUSIONS In patients with acute coronary syndromes, the addition of vorapaxar to standard therapy did not significantly reduce the primary composite end point but significantly increased the risk of major bleeding, including intracranial hemorrhage. (Funded by Merck; TRACER ClinicalTrials.gov number, NCT00527943.)

Endogenous opioid peptide-mediated neurotransmission in central and pericentral nuclei of the inferior colliculus recruits mu(1)-opioid receptor to modulate post-ictal antinociception

Background: The aim of the present work was to investigate the involvement of the mu(1)-endogenous opioid peptide receptor-mediated system in post-ictal antinociception. Methods: Antinociceptive responses were determined by the tail-flick test after pre-treatment with the selective mu(1)-opioid receptor antagonist naloxonazine, peripherally or centrally administered at different doses. Results: 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 mu(1)-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 mu(1)-opioid receptor decreased the duration of seizures. Conclusion: mu(1)-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 mu(1)-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. (C) 2011 Elsevier Ltd. All rights reserved.

beta(1) Adrenergic receptor is key to cold- and diet-induced thermogenesis in mice

Brown adipose tissue (BAT) is predominantly regulated by the sympathetic nervous system (SNS) and the adrenergic receptor signaling pathway. Knowing that a mouse with triple beta-receptor knockout (KO) is cold intolerant and obese, we evaluated the independent role played by the beta(1) isoform in energy homeostasis. First, the 30 min i.v. infusion of norepinephrine (NE) or the beta(1) selective agonist dobutamine (DB) resulted in similar interscapular BAT (iBAT) thermal response in WT mice. Secondly, mice with targeted disruption of the beta(1) gene (KO of beta(1) adrenergic receptor (beta 1KO)) developed hypothermia during cold exposure and exhibited decreased iBAT thermal response to NE or DB infusion. Thirdly, when placed on a high-fat diet (HFD; 40% fat) for 5 weeks, beta 1KO mice were more susceptible to obesity than WT controls and failed to develop diet-induced thermogenesis as assessed by BAT Ucp1 mRNA levels and oxygen consumption. Furthermore, beta 1KO mice exhibited fasting hyperglycemia and more intense glucose intolerance, hypercholesterolemia, and hypertriglyceridemia when placed on the HFD, developing marked non-alcoholic steatohepatitis. In conclusion, the beta(1) signaling pathway mediates most of the SNS stimulation of adaptive thermogenesis. Journal of Endocrinology (2012) 214, 359-365

A gymnosperm homolog of SOMATIC EMBRYOGENESIS RECEPTOR-LIKE KINASE-1 (SERK1) is expressed during somatic embryogenesis

The physiological and molecular processes controlling zygotic and somatic embryo development in angiosperms are mediated by a hierarchically organized program of gene expression. Despite the overwhelming information available about the molecular control of the embryogenic processes in angiosperms, little is known about these processes in gymnosperms. Here we describe the cloning and characterization of the expression pattern of the Araucaria angustifolia putative homolog of a SOMATIC EMBRYOGENESIS RECEPTOR-LIKE KINASE (SERK) gene family member, designated as AaSERK1. The Araucaria AaSERK1 gene encodes a leucine-rich repeat receptor-like kinase showing significant similarity to angiosperm homologs of SERK1, known to be involved in early somatic and zygotic embryogenesis. Accordingly, RT-PCR results showed that AaSERK1 is preferentially expressed in Araucaria embryogenic cell cultures. Additionally, in situ hybridization results showed that AaSERK1 transcripts initially accumulate in groups of cells at the periphery of the embryogenic calli and then are restricted to the developing embryo proper. Our results indicate that AaSERK1 might have a role during somatic embryogenesis in Araucaria, suggesting a potentially conserved mechanism, involving SERK-related leucine-rich repeat receptor-like kinases, in the embryogenic processes among all seed plants.

Inhibition of cannabinoid CB1 receptor upregulates Slc2a4 expression via nuclear factor-kappa B and sterol regulatory element-binding protein-1 in adipocytes

Evidences have suggested that the endocannabinoid system is overactive in obesity, resulting in enhanced endocannabinoid levels in both circulation and visceral adipose tissue. The blockade of cannabinoid receptor type 1 (CB1) has been proposed for the treatment of obesity. Besides loss of body weight, CB1 antagonism improves insulin sensitivity, in which the glucose transporter type 4 (GLUT4) plays a key role. The aim of this study was to investigate the modulation of GLUT4-encoded gene (Slc2a4 gene) expression by CB1 receptor. For this, 3T3-L1 adipocytes were incubated in the presence of a highly selective CB1 receptor agonist (1 mu M arachidonyl-2'-chloroethylamide) and/or a CB1 receptor antagonist/inverse agonist (0.1, 0.5, or 1 mu M AM251, 1-(2,4-dichlorophenyl)-5-(4-iodophenyl)-4-methyl-N-1-piperidinyl-1H-pyrazole-3-carboxamide). After acute (2 and 4 h) and chronic (24 h) treatments, cells were harvested to evaluate: i) Slc2a4, Cnr1 (CB1 receptor-encoded gene), and Srebf1 type a (SREBP-1a type-encoded gene) mRNAs (real-time PCR); ii) GLUT4 protein (western blotting); and iii) binding activity of nuclear factor (NF)-kappa B and sterol regulatory element-binding protein (SREBP)-1 specifically in the promoter of Slc2a4 gene (electrophoretic mobility shift assay). Results revealed that both acute and chronic CB1 receptor antagonism greatly increased (similar to 2.5-fold) Slc2a4 mRNA and protein content. Additionally, CB1-induced upregulation of Slc2a4 was accompanied by decreased binding activity of NF-kappa B at 2 and 24 h, and by increased binding activity of the SREBP-1 at 24 h. In conclusion, these findings reveal that the blockade of CB1 receptor markedly increases Slc2a4/GLUT4 expression in adipocytes, a feature that involves NF-kappa B and SREBP-1 transcriptional regulation. Journal of Molecular Endocrinology (2012) 49, 97-106

Preservation of Alpha-3 Neuronal Nicotinic Acetylcholine Receptor Expression in Sympathetic Ganglia After Brain Death

The goal of this study was to evaluate if the immunohistochemical expression of alpha-3 neuronal nicotinic acetylcholine receptor subunit in sympathetic ganglia remains stable after brain death, determining the possible use of sympathetic thoracic ganglia from subjects after brain death as study group. The third left sympathetic ganglion was resected from patients divided in two groups: BD-organ donors after brain death and CON-patients submitted to sympathectomy for hyperhidrosis (control group). Immunohistochemical staining for alpha-3 neuronal nicotinic acetylcholine receptor subunit was performed; strong and weak expression areas were quantified in both groups. The BD group showed strong alpha-3 neuronal nicotinic acetylcholine receptor expression in 6.55% of the total area, whereas the CON group showed strong expression in 5.91% (p = 0.78). Weak expression was found in 6.47% of brain-dead subjects and in 7.23% of control subjects (p = 0.31). Brain death did not affect the results of the immunohistochemical analysis of sympathetic ganglia, and its use as study group is feasible.