Open AccessEffects of Endothelin on Arterial Pressure and Venous Tone in Intact and Hexamethonium-Treated Conscious Rats
Author(s) -
R Waite,
Catherine C.Y. Pang
Publication year - 1990
Publication title -
journal of cardiovascular pharmacology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.762
H-Index - 100
eISSN - 1533-4023
pISSN - 0160-2446
DOI - 10.1097/00005344-199012000-00012
Subject(s) - hexamethonium , medicine , mean circulatory filling pressure , endothelin receptor , blood pressure , anesthesia , mean arterial pressure , ganglionic blocker , heart rate , endocrinology , central venous pressure , acetylcholine , receptor
The dose-response effects of the potent vasoconstrictor peptide endothelin on mean arterial pressure (MAP), heart rate (HR), and mean circulatory filling pressure (MCFP), an index of body venous tone, were investigated in conscious and unrestrained, intact rats as well as in rats continuously infused with the ganglionic blocker hexamethonium. The dose of hexamethonium selected was that which reduced the reflex tachycardia induced by i.v. injections of acetylcholine by 50%. In intact rats and rats pretreated with hexamethonium, i.v. injections of endothelin caused dose-dependent increases in MAP and decreases in HR. Low doses of endothelin did not affect MCFP while the highest dose in the intact rat, and the two highest doses in hexamethonium-treated rats, caused small but significant increases in MCFP. Our results suggest that endothelin has small effects on body venous tone in contrast to its effectiveness in raising arterial pressure.