Influences of beta-blocking agents on cardiovascular actions induced by endothelin-3 administered intracerebroventricularly in anesthetized rats.
Possible involvement that the pressor and positive chronotropic effects of endothelin-3 (ET-3) administered intracerebroventricularly (i.c.v.) participate in the central beta-adrenoceptor has been studied in urethane anesthetized rats. ET-3 administered i.c.v. at dose of 50 pmol elicited the increase in blood pressure and heart rate over a long duration, but a dose of 30 pmol had a minimal effect. These cardiovascular responses to ET-3 were significantly reduced by intravenous pretreatment with pentolinium, ganglionic blocking agent, and phentolamine, alpha-blocker. Also pressor responses to ET-3 were abolished dose-dependently by i.c.v. pretreatment with propranolol at a dose of 1 mumol, nonselective beta-blocker and ICI 118551, beta 2-selective adrenoceptor blocker, but not by i.c.v. pretreatment with metoprolol, atenolol, beta 1-selective blocker, procaine and phentolamine. These results suggest that ET-3 may play a role in cardiovascular regulation through the activation of the sympathetic nervous system involved in the central beta 2-adrenoceptor system.
Ono
N
N
Department of Pharmacology, Faculty of Pharmaceutical Sciences, Fukuoka University, Japan.
Kaneko
M
M
D000319:Adrenergic beta-Antagonists / Q000494:pharmacology*; D000758:Anesthesia; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects*; D001921:Brain / Q000187:drug effects*; D016232:Endothelins / Q000494:pharmacology*; D006339:Heart Rate / Q000187:drug effects*; D007276:Injections, Intraventricular; D008297:Male; D010646:Phentolamine / Q000494:pharmacology; D011343:Procaine / Q000494:pharmacology; D011412:Propanolamines / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar
D000319:Adrenergic beta-Antagonists; D016232:Endothelins; D011412:Propanolamines; C026777:ICI 118551; D011343:Procaine; D010646:Phentolamine