Release of atrial natriuretic factor induced by the A1 adenosine receptor agonist 2-chloro-N6-cyclopentyl-adenosine in the rat.

The effect of the adenosine receptor agonists, 2-chloro-N6-cyclopentyladenosine (CCPA) and 2-hexynyl-adenosine-5'-N-ethylcarboxamide (HENECA) on atrial natriuretic factor (ANF) release was investigated. The A1 adenosine receptor agonist CCPA markedly increased plasma ANF levels, following subcutaneous (s.c.), but not intracerebroventricular injection. ANF release evoked by the s.c. injection of CCPA was completely abolished by s.c. pretreatment with the selective A1 adenosine receptor antagonist, 1,3-dipropyl-8-cyclopentylxanthine. The A2 adenosine receptor agonist HENECA did not produce ANF release. The results of the present study suggest that peripheral adenosine mechanisms might be involved in the control of ANF secretion, through the activation of A1 adenosine receptors. Preliminary results show that CCPA produces ANF release also from isolated atria, thus suggesting that its action on ANF release is, at least in part, direct, and not only a consequence of cardiovascular modifications.