Demonstration of specific receptors for adenosine in guinea-pig myocardium.
Adenosine analogues N6-phenylisopropyladenosine and 5'-N-ethylcarboxamidoadenosine inhibit cardiac adenylate cyclase in a concentration dependent manner. Inhibition of adenylate cyclase required the presence of guanosine-triphosphate and Mg2+ ion. The concentration of Na+ ion was critically important: maximal inhibition was observed at 50 mmol/l Na+. 8-Phenyltheophylline and isobutylmethylxanthine antagonized the inhibition of adenylate cyclase mediated by adenosine analogues. Adenosine receptors of the inhibitory type (R1 or A1) are present in guinea-pig myocardium and may mediate some actions of adenosine.
D000241:Adenosine / Q000378:metabolism*; D000067956:Adenylyl Cyclase Inhibitors; D000818:Animals; D006168:Guinea Pigs; D008274:Magnesium / Q000494:pharmacology; D008297:Male; D009206:Myocardium / Q000378:metabolism*; D011956:Receptors, Cell Surface / Q000378:metabolism*; D011983:Receptors, Purinergic; D012964:Sodium / Q000494:pharmacology
D000067956:Adenylyl Cyclase Inhibitors; D011956:Receptors, Cell Surface; D011983:Receptors, Purinergic; D012964:Sodium; D008274:Magnesium; D000241:Adenosine