beta1-Adrenoceptor-mediated relaxation by norepinephrine in dog hepatic arteries.
Dog hepatic arterial strips treated with prazosin responded to norepinephrine with concentration-related, endothelium-independent relaxations, the maximal response being 81.7% of the papaverine-induced maximal relaxation that was markedly greater than that in renal arteries. The norepinephrine-induced relaxation in hepatic arteries was significantly attenuated by metoprolol but not influenced by butoxamine. Relaxant responses to norepinephrine of dog hepatic arteries appear to be mediated by the beta1-adrenoceptor subtype, like those of coronary arteries. Evidence for functioning of the beta1-subtype in hepatic arteries would contribute to the analysis of neural and hormonal regulation of blood flow in the liver.
Shiraishi
S
S
Department of Pharmacology, Shiga University of Medical Sciences, Seta, Ohtsu, Japan.
Okamura
T
T
Toda
N
N
D000317:Adrenergic alpha-Antagonists / Q000494:pharmacology; D000818:Animals; D004285:Dogs; D004730:Endothelium, Vascular / Q000502:physiology; D005260:Female; D006499:Hepatic Artery / Q000187:drug effects / Q000502:physiology*; D066298:In Vitro Techniques; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects; D009126:Muscle Relaxation / Q000187:drug effects / Q000502:physiology; D009131:Muscle, Smooth, Vascular / Q000187:drug effects / Q000502:physiology*; D009638:Norepinephrine / Q000494:pharmacology*; D018342:Receptors, Adrenergic, beta-1 / Q000502:physiology*
D000317:Adrenergic alpha-Antagonists; D018342:Receptors, Adrenergic, beta-1; D009638:Norepinephrine