ATP-sensitive K+ channel opener pinacidil augments beta 1-adrenoceptor-induced coronary vasodilation in dogs.
The opening of ATP-sensitive K+ (K+ATP) channels contributes to the mechanism of metabolic coronary vasodilation. The aim of the present study was to determine whether K+ATP channel opener pinacidil augments coronary vasodilation induced by beta-adrenoceptor stimulation. In anesthetized dogs, coronary vasodilation in response to intracoronary infusion of a beta 1-adrenoceptor agonist denopamine, selective beta 2-adrenoceptor stimulation with isoproterenol after bisoprolol or nitroglycerin was studied before and during simultaneous intracoronary infusion of pinacidil at a dose of 1 microgram/min, which had no effect on basal hemodynamics. Pinacidil augmented the denopamine-induced increase in coronary blood flow (CBF) from 38 +/- 9 to 66 +/- 16% (P < 0.05) but did not affect the denopamine-induced by isoproterenol or nitroglycerin. Thus pinacidil selectively augmented beta 1-adrenoceptor-mediated coronary vasodilation. These observations suggest that the K+ATP channel opener pinacidil may increase myocardial perfusion during metabolic stress associated with beta 1-adrenoceptor stimulation.
Katsuda
Y
Y
Research Institute of Angiocardiology, Kyushu University School of Medicine, Fukuoka, Japan.
Egashira
K
K
Ueno
H
H
Arai
Y
Y
Akatsuka
Y
Y
Kuga
T
T
Shimokawa
H
H
Takeshita
A
A
D000255:Adenosine Triphosphate / Q000494:pharmacology*; D000318:Adrenergic beta-Agonists / Q000494:pharmacology; D000818:Animals; D017298:Bisoprolol / Q000494:pharmacology; D003326:Coronary Circulation / Q000187:drug effects / Q000502:physiology*; D004285:Dogs; D004983:Ethanolamines / Q000494:pharmacology; D006146:Guanidines / Q000494:pharmacology*; D005996:Nitroglycerin / Q000494:pharmacology; D020110:Pinacidil; D015221:Potassium Channels / Q000187:drug effects*; D011943:Receptors, Adrenergic, beta / Q000502:physiology*; D013997:Time Factors; D014664:Vasodilation / Q000502:physiology*; D014665:Vasodilator Agents / Q000494:pharmacology*
D000318:Adrenergic beta-Agonists; D004983:Ethanolamines; D006146:Guanidines; D015221:Potassium Channels; D011943:Receptors, Adrenergic, beta; D014665:Vasodilator Agents; D020110:Pinacidil; D000255:Adenosine Triphosphate; D005996:Nitroglycerin; C037293:denopamine; D017298:Bisoprolol