Role of endothelin in stress-induced hypertension.
In this study we investigated the role of endogenous endothelin in the cardiovascular response to acute stress, ie mild footshocks in conscious rats. Footshock-stress significantly increased mean arterial pressure and heart rate (P < 0.05). Peripheral or intracerebroventricular (IVT) administration of BQ 788, a selective antagonist of ET(B) receptor, did not alter pressor response to footshocks. Intraperitoneal injections of BQ 123 (1 mg/kg), a selective antagonist of the ET(A)-receptor, had a tendency to decrease, while BQ 123 (203 ng/5 microl) IVT administration significantly reduced the pressor response to footshocks (-12 mm Hg, P < 0.001). Neither ET(A) nor ET(B) antagonists, when injected centrally or peripherally, altered basal blood pressure or heart rate. Our results may indicate a role of brain endothelin in the sympathetic mediated cardiovascular response to stress, via stimulation of ET(A) receptor.
Garrido
M R
MR
Laboratory of Neuropeptides. School of Pharmacy. Universidad Central de Venezuela. Caracas, Venezuela.
Israel
A
A
D000704:Analysis of Variance; D000818:Animals; D000959:Antihypertensive Agents / Q000494:pharmacology*; D004597:Electroshock; D065128:Endothelin Receptor Antagonists; D016232:Endothelins / Q000502:physiology*; D006973:Hypertension / Q000378:metabolism*; D008297:Male; D009842:Oligopeptides / Q000494:pharmacology*; D010456:Peptides, Cyclic / Q000494:pharmacology*; D010880:Piperidines / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley
D000959:Antihypertensive Agents; D065128:Endothelin Receptor Antagonists; D016232:Endothelins; D009842:Oligopeptides; D010456:Peptides, Cyclic; D010880:Piperidines; C086539:BQ 788; C072247:cyclo(Trp-Asp-Pro-Val-Leu)