Hypotensive effect of clonidine is not mediated by enhanced baroreflex gain in rats.
Journal Article (Journal Article)
We wished to examine whether enhanced depressor baroreflexes contribute to the hypotensive effect of clonidine in rats. Clonidine's hypotensive effect and clonidine's effect on baroreflex gain mean heart rate/mean blood pressure, (delta HR/delta BP) were compared under two conditions: in conscious rats with intact baroreflex control of HR, and in pentobarbital-anesthetized (PA) rats in which baroreflex control of HR is obtunded. Clonidine produced greater hypotension and bradycardia in PA rats than in conscious rats, but this greater hypotension was not associated with enhancement of baroreflex gain. Instead, clonidine-induced hypotension in PA rats was associated with a further decrease in baroreflex gain, whereas hypotension in conscious rats was not associated with any change in baroreflex gain. Selective pharmacologic blockade of sympathetic (i.e., with atenolol treatment) or parasympathetic (i.e., with methyl-atropine treatment) control of HR showed that clonidine decreased baroreflex gain in PA rats through inhibition of sympathetic control of HR. This study suggests that clonidine's hypotensive effect is not associated with enhancement of reflex bradycardic responses in rats.
Full Text
Duke Authors
Cited Authors
- Watkins, L; Maixner, W
Published Date
- February 1993
Published In
Volume / Issue
- 21 / 2
Start / End Page
- 264 - 271
PubMed ID
- 7679161
International Standard Serial Number (ISSN)
- 0160-2446
Digital Object Identifier (DOI)
- 10.1097/00005344-199302000-00012
Language
- eng
Conference Location
- United States