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| Picanço-Diniz,D.L.W.; Valença,M.M.; Antunes-Rodrigues,J.. |
| 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... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Cyclopentyltheophylline; Dibutyryl cAMP; R-PIA; Pertussis toxin; Cholera toxin. |
| Ano: 2006 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2006001100013 |
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| Ventura,R.R.; Gomes,D.A.; Reis,W.L.; Elias,L.L.K.; Castro,M.; Valença,M.M.; Carnio,E.C.; Rettori,V.; McCann,S.M.; Antunes-Rodrigues,J.. |
| The central nervous system plays an important role in the control of renal sodium excretion. We present here a brief review of physiologic regulation of hydromineral balance and discuss recent results from our laboratory that focus on the participation of nitrergic, vasopressinergic, and oxytocinergic systems in the regulation of water and sodium excretion under different salt intake and hypertonic blood volume expansion (BVE) conditions. High sodium intake induced a significant increase in nitric oxide synthase (NOS) activity in the medial basal hypothalamus and neural lobe, while a low sodium diet decreased NOS activity in the neural lobe, suggesting that central NOS is involved in the control of sodium balance. An increase in plasma concentrations in... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Vasopressin; Oxytocin; ANP; Nitric oxide; Blood volume expansion; Sodium diet. |
| Ano: 2002 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2002000900011 |
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| Picanço-Diniz,D.L.W.; Valença,M.M.; Favaretto,A.L.V.; McCann,S.M.; Antunes-Rodrigues,J.. |
| We investigated the participation of A1 or A2 receptors in the gonadotrope and their role in the regulation of LH and FSH secretion in adult rat hemipituitary preparations, using adenosine analogues. A dose-dependent inhibition of LH and FSH secretion was observed after the administration of graded doses of the R-isomer of phenylisopropyladenosine (R-PIA; 1 nM, 10 nM, 100 nM, 1 µM and 10 µM). The effect of R-PIA (10 nM) was blocked by the addition of 8-cyclopentyltheophylline (CPT), a selective A1 adenosine receptor antagonist, at the dose of 1 µM. The addition of an A2 receptor-specific agonist, 5-N-methylcarboxamidoadenosine (MECA), at the doses of 1 nM to 1 µM had no significant effect on LH or FSH secretion, suggesting the absence of this receptor... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Adenosine; LH; FSH; A1 receptor; Anterior pituitary. |
| Ano: 1999 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X1999000900017 |
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| Picanço-Diniz,D.L.W.; Valença,M.M.; Favaretto,A.L.V.; Antunes-Rodrigues,J.. |
| We investigated the effects of adenosine on prolactin (PRL) secretion from rat anterior pituitaries incubated in vitro. The administration of 5-N-methylcarboxamidoadenosine (MECA), an analog agonist that preferentially activates A2 receptors, induced a dose-dependent (1 nM to 1 µM) increase in the levels of PRL released, an effect abolished by 1,3-dipropyl-7-methylxanthine, an antagonist of A2 adenosine receptors. In addition, the basal levels of PRL secretion were decreased by the blockade of cyclooxygenase or lipoxygenase pathways, with indomethacin and nordihydroguaiaretic acid (NDGA), respectively. The stimulatory effects of MECA on PRL secretion persisted even after the addition of indomethacin, but not of NDGA, to the medium. MECA was unable to... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Adenosine; Prolactin; A2 receptor; Pituitary gland. |
| Ano: 2002 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2002000700015 |
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