Endothelium-dependent higenamine-induced aortic relaxation in isolated rat aorta.
The pharmacological action of higenamine in isolated rat aorta was investigated. Although the beta-adrenoceptor antagonist propranolol (1 x 10(-5) M) completely blocked the beta-adrenoceptor agonist higenamine in inducing a positive chronotropic activity in isolated mouse atria, the higenamine-induced aortic relaxation was not completely antagonized by this concentration of propranolol. The present data also demonstrate that the higenamine-induced aortic relaxation was attenuated in the absence of endothelium. These findings suggest that the beta-adrenoceptor specificity to higenamine in aorta is different from that of beta-1 in atria; moreover, the beta-adrenoceptors sensitive to higenamine are mainly located in the endothelial layer.
Wong
K K
KK
Department of Pharmacology, National Yang Ming University, Taipei, Taiwan, Republic of China.
Lo
C F
CF
Chen
C M
CM
D000318:Adrenergic beta-Agonists / Q000494:pharmacology*; D000319:Adrenergic beta-Antagonists / Q000494:pharmacology; D000470:Alkaloids / Q000494:pharmacology*; D000818:Animals; D001011:Aorta / Q000187:drug effects* / Q000502:physiology; D004730:Endothelium, Vascular / Q000187:drug effects* / Q000502:physiology; D066298:In Vitro Techniques; D008297:Male; D051379:Mice; D008813:Mice, Inbred ICR; D009126:Muscle Relaxation / Q000187:drug effects / Q000502:physiology; D011433:Propranolol / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D044005:Tetrahydroisoquinolines
D000318:Adrenergic beta-Agonists; D000319:Adrenergic beta-Antagonists; D000470:Alkaloids; D044005:Tetrahydroisoquinolines; D011433:Propranolol; C012348:higenamine