Contribution of NO, ATP-sensitive K+ channels and prostaglandins to adenosine receptor agonists-induced relaxation of the rat tail artery.
The mechanism of relaxation in the rat tail artery induced by the adenosine A(1) receptor-selective agonist N(6)-cyclohexyladenosine (CHA, 10 nM-300 microM) and the adenosine A1/A(2a) receptor agonist 5'-N-ethylcarboxamidoadenosine (NECA, 10 nM-300 microM) has been characterized. To do this, we used alpha(1)-receptor agonist phenylephrine to evoke contraction (10 microM), and inhibitors of nitric oxide synthase (L-NAME, 10 microM), ATP-sensitive K(+) channels (glibenclamide, 10 microM) and prostaglandin synthesis (indomethacin, 10 microM). CHA and NECA induced relaxation of rat-tail artery by 80% and 70% in a concentration-dependent manner, respectively. The relaxation effect of NECA was completely abolished in the presence of L-NAME, while glibenclamide and indomethacin prevented CHA-induced relaxation of the rat tail artery by approximately 25% and 40%, respectively. Our results indicate that nonspecific effects such nitric oxide and prostaglandins release or the activation of potassium channels significantly contributed to the effects of CHA and NECA.
Kedzior
Katarzyna
K
Department of Pharmacology, Medical University of Gdańsk, Debowa 23, PL 80-204 Gdańsk, Poland.
Szczepańska
Renata
R
Kocić
Ivan
I
D000241:Adenosine / Q000031:analogs & derivatives / Q000494:pharmacology; D019830:Adenosine-5'-(N-ethylcarboxamide) / Q000494:pharmacology; D000818:Animals; D001158:Arteries / Q000187:drug effects / Q000502:physiology; D054086:KATP Channels / Q000502:physiology*; D008297:Male; D009569:Nitric Oxide / Q000502:physiology*; D011453:Prostaglandins / Q000502:physiology*; D058906:Purinergic P1 Receptor Agonists; D051381:Rats; D017208:Rats, Wistar; D018047:Receptors, Purinergic P1 / Q000502:physiology; D013623:Tail / Q000098:blood supply; D014664:Vasodilation / Q000187:drug effects*
D054086:KATP Channels; D011453:Prostaglandins; D058906:Purinergic P1 Receptor Agonists; D018047:Receptors, Purinergic P1; D009569:Nitric Oxide; D019830:Adenosine-5'-(N-ethylcarboxamide); C027513:N(6)-cyclohexyladenosine; D000241:Adenosine