Facilitation of noradrenaline release by adenosine A_2A receptors in the epididymal portion and adenosine A_2B receptors in the prostatic portion of the rat vas deferens

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• 作者：Queiroz ; Gló ; ria ; Diniz ; Carmen ; Gonç ; alves ; Jorge
• 关键词：Adenosine A₁ receptor ; Adenosine A_2A receptor ; Adenosine A_2B receptor ; Noradrenaline ; Vas deferens ; rat ; Distribution ; Differential
• 刊名：European Journal of Pharmacology
• 出版年：2002
• 出版时间：July 12, 2002
• 年：2002
• 卷：448
• 期：1
• 页码：45-50
• 全文大小：178 K

文摘

The adenosine-receptor modulation of noradrenaline release was compared in prostatic and epididymal portions of rat vas deferens. In both portions, tritium overflow elicited by electrical stimulation (100 pulses/8 Hz) was reduced by the adenosine A₁ receptor agonist, N⁶-cyclopentyladenosine, and enhanced by the nonselective receptor agonist, 5′-N-ethylcarboxamidoadenosine, in the presence of the adenosine A₁ receptor antagonist, 1,3-dipropyl-8-cyclopentyl-1,3-dipropylxanthine (DPCPX; 20 and 100 nM). The adenosine A_2A receptor agonist, 2-p-(2-carboxyethyl)phenethyl-amino-5′-N-ethylcarboxamidoadenosine, increased tritium overflow, but only in the epididymal portion. The enhancement caused by NECA was prevented by the adenosine A_2A receptor antagonist, 4-(2-[7-amino-2-(2-furyl)[1,2,4]triazolo-[2,3-a][1,3,5]triazin-5-ylamino]ethyl)phenol (ZM 241385; 20 nM), in the epididymal and by the adenosine A_2B receptor antagonist, alloxazine (1 56;M), in the prostatic portion. Inhibition of adenosine uptake enhanced tritium overflow in both portions, an effect blocked by ZM 241385 in the epididymal and by alloxazine in the prostatic portion. The results indicate that adenosine exerts an adenosine A₁ receptor-mediated inhibition, in both portions, and facilitation mediated by adenosine A_2A receptors in the epididymal and by A_2B receptors in the prostatic portion.