title: Increase in the vasorelaxant potency of K(ATP) channel opening drugs by adenosine A(1) and A(2) receptors in the pig coronary artery.
abstract: Myograph recording from ring segments of pig small coronary arteries was used to investigate the effects of adenosine receptor activation on the vasorelaxant potency of ATP-sensitive K(+) channel opening drugs. Receptor activation with 2-chloroadenosine (2-CA, 300 nM) increased the potency of both nicorandil and levcromakalim, shifting the pEC(50)s from 4.68+/-0.03 to 5.05+/-0.04 and from 6.34+/-0.06 to 6.72+/-0.06, respectively (P<0.05 in each case). Experiments with selective adenosine receptor agonists (2-chloro-N(6)-cyclopentyladenosine (CCPA), 2-p-(2-carboxyethyl)phenethylamino-5'-N-ethylcarboxamidoadenosine hydrochloride (CGS 21680)) and antagonists (8-cyclopentyl-1, 3-dipropylxanthine (DPCPX), 4-(2-[7-amino-2-(2-furyl)[1,2, 4]triazolo[2,3-a] [1,3,5]triazin-5-ylamino]ethyl)phenol (ZM 241385)) suggest that both A(1) and A(2a) receptors can increase the potency of nicorandil, while that of levcromakalim is increased only by A(2) receptors. Adenosine receptor activation did not affect the potency of pinacidil. Thus, adenosine receptor activation can increase the potency of some K(+) channel opening drugs to relax coronary arteries, but the details of the interaction with adenosine receptors depend on the particular drug.
authors.affiliation: Ion Channel Group, Department of Cell Physiology and Pharmacology, University of Leicester, PO Box 138, Leicester, UK.
authors.forename: C S
authors.initials: CS
authors.lastname: Davie
authors.forename: D E
authors.initials: DE
authors.lastname: Everitt
authors.forename: N B
authors.initials: NB
authors.lastname: Standen
mesh_terms: D018528:ATP-Binding Cassette Transporters; D000241:Adenosine / Q000031:analogs & derivatives / Q000494:pharmacology; D000818:Animals; D003331:Coronary Vessels / Q000187:drug effects*; D019806:Cromakalim / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004347:Drug Interactions; D066298:In Vitro Techniques; D054086:KATP Channels; D020108:Nicorandil / Q000494:pharmacology; D010627:Phenethylamines / Q000494:pharmacology; D020110:Pinacidil / Q000494:pharmacology; D015221:Potassium Channels / Q000819:agonists*; D024661:Potassium Channels, Inwardly Rectifying; D058906:Purinergic P1 Receptor Agonists; D058915:Purinergic P1 Receptor Antagonists; D013552:Swine; D014227:Triazines / Q000494:pharmacology; D014230:Triazoles / Q000494:pharmacology; D014665:Vasodilator Agents / Q000494:pharmacology*; D014970:Xanthines / Q000494:pharmacology
chemical_list: D018528:ATP-Binding Cassette Transporters; D054086:KATP Channels; D010627:Phenethylamines; D015221:Potassium Channels; D024661:Potassium Channels, Inwardly Rectifying; D058906:Purinergic P1 Receptor Agonists; D058915:Purinergic P1 Receptor Antagonists; D014227:Triazines; D014230:Triazoles; D014665:Vasodilator Agents; D014970:Xanthines; C097270:ZM 241385; C092520:uK-ATP-1 potassium channel; D019806:Cromakalim; C061282:2-(4-(2-carboxyethyl)phenethylamino)-5'-N-ethylcarboxamidoadenosine; D020108:Nicorandil; C058394:2-chloro-N(6)cyclopentyladenosine; D020110:Pinacidil; C051360:1,3-dipropyl-8-cyclopentylxanthine; D000241:Adenosine