Calcium antagonist verapamil inhibits adenosine-induced renal vasoconstriction in the dog.
Calcium-dependence of the adenosine-induced renal vasoconstriction was studied in dogs anaesthetized with pentobarbital. Close intraarterial (i.a.) infusion of adenosine (40 and 100 micrograms X min-1) elicited a significant blood flow decrease followed by partial recovery during the 2 min infusion periods as measured with an electromagnetic flow probe. I.a. infusion of verapamil (100 micrograms X min-1) blocked the constrictor response. Verapamil also reduced the vasoconstriction produced by i.a. angiotensin II (0.1 micrograms X min-1) or adrenaline (0.6 micrograms X min-1). Blood pressure remained unchanged throughout all the interventions. The results indicate that the adenosine-induced renal vascular response depends on the availability of extracellular Ca2+ to the contractile mechanism of smooth muscle, a property shared by other well known renal constrictor agents.
D000241:Adenosine / Q000037:antagonists & inhibitors* / Q000494:pharmacology; D000804:Angiotensin II / Q000037:antagonists & inhibitors; D000818:Animals; D002118:Calcium / Q000378:metabolism / Q000494:pharmacology*; D004285:Dogs; D004305:Dose-Response Relationship, Drug; D004837:Epinephrine / Q000037:antagonists & inhibitors; D005260:Female; D006439:Hemodynamics / Q000187:drug effects; D007473:Ion Channels / Q000378:metabolism; D007668:Kidney / Q000098:blood supply*; D008297:Male; D011817:Rabbits; D012079:Renal Circulation / Q000187:drug effects*; D014661:Vasoconstriction / Q000187:drug effects*; D014700:Verapamil / Q000494:pharmacology*
D007473:Ion Channels; D000804:Angiotensin II; D014700:Verapamil; D000241:Adenosine; D002118:Calcium; D004837:Epinephrine