Renal effects of selective adenosine receptor agonists in anesthetized rats.
Exogenous adenosine affects renal hemodynamics, renal tubular transport processes, and the secretion of renin. However, adenosine is not a selective agonist; it activates both A1 and A2 cell-surface receptors and it binds to an intracellular P-site that inhibits adenylate cyclase activity. Recent in vitro studies have suggested that activation of A1- and A2- adenosine receptors results in opposite effects on renin secretion. The purpose of these experiments was to examine the renal effects of A1- and A2-adenosine receptor agonists in vivo. 5'-N-ethylcarboxamide adenosine (NECA), 2-chloroadenosine (2-CLA), and N6-cyclohexyladenosine (CHA) were infused intravenously at rates that produced comparable decreases in systemic arterial blood pressure. All three of these adenosine analogues produced comparable decreases in para-aminohippurate (PAH) and inulin clearances and in Na and K excretion rates. CHA, an A1-selective agonist, markedly decreased plasma renin concentration (PRC), whereas NECA, an A2-selective agonist, markedly increased PRC; 2-CLA, a nonselective agonist, produced a smaller increase in PRC. Taken together, these results suggest that occupation of A1- and A2-receptors inhibits and stimulates renin secretion in vivo, independently of the effects of these adenosine receptor agonists on arterial blood pressure, renal hemodynamics, and tubular Na and K transport.
D000241:Adenosine / Q000378:metabolism*; D000758:Anesthesia; D000818:Animals; D001011:Aorta; D005919:Glomerular Filtration Rate; D007668:Kidney / Q000502:physiology*; D008026:Ligation; D008297:Male; D009994:Osmolar Concentration; D011188:Potassium / Q000652:urine; D051381:Rats; D011919:Rats, Inbred Strains; D011956:Receptors, Cell Surface / Q000502:physiology*; D012083:Renin / Q000097:blood; D012964:Sodium / Q000652:urine; D010130:p-Aminohippuric Acid / Q000378:metabolism
D011956:Receptors, Cell Surface; D012964:Sodium; D012083:Renin; D000241:Adenosine; D011188:Potassium; D010130:p-Aminohippuric Acid