Effects of adenosine-receptor agonists on renin release in anaesthetized rats

Objective: To investigate the effects of the interaction between adenosine receptors and renal nerves on renin release. Materials and methods: The effects on renin secretion of A1 (2-chloro-N6-cyclopentil- adenosine) and A2 (2-hexynil-5’-N-ethyl-carboxamido-adenosine) adenosine-receptor agonists were studied in two groups of anaesthetized rats, each with one kidney surgically denervated. Arterial blood pressure and the renal blood flow of innervated and denervated kidneys were continuously recorded. Cannulae were inserted into both renal veins through femoral veins. After 1 h of rest, A1 and A2 agonists were intravenously infused for 30 min in the two groups of rats. Plasma renin activity was measured by radioimmunoassay in blood samples drawn simultaneously from both renal veins and the femoral artery before and after the drug infusion. Results: Infusions of A1 and A2 agonists produced comparable hypotensive effects. During A1 agonist administration, the heart rate decreased significa...