Selective A1 adenosine receptor antagonism augments beta-adrenergic-induced renin release in vivo

This study determines, in vivo, whether endogenous adenosine/A1 receptor interactions at juxtaglomerular cells restrain the release of renin induced by receptor-mediated activation of the adenosine 3',5'–cyclic monophosphate pathway and whether endogenous adenosine/A2 receptor interactions diminish this restraining response. The following four pharmacological probes were employed: 1) 1,3-dipropyl-8-cyclopentylxanthine (DPCPX) and 2) FK-453, both selective A1 receptor antagonists; 3) FR-113452, a nearly inactive enantiomer of FK-453; and 4) KF-17837, a selective A2 receptor blocker. Adult Sprague-Dawley rats were prepared (adrenalectomized, renal denervated, uninephrectomized, and treated with indomethacin, aldosterone, and hydrocortisone) to minimize endogenous stimulation of renin release and received either vehicle (control group) or one of the four drugs. Intrarenal infusions of isoproterenol (3, 30, and 100 ng.kg-1.min-1) caused dose-related increases in plasma renin activity (PRA). This PRA response ...