Faculty Collaboration Database

Direct coronary and cerebral vascular responses to dexmedetomidine. Significance of endogenous nitric oxide synthesis. Anesthesiology 1992 Nov;77(5):998-1006

Date

11/01/1992

Pubmed ID

1359812

DOI

10.1097/00000542-199211000-00024

Scopus ID

2-s2.0-0026440614 (requires institutional sign-in at Scopus site)   60 Citations

Abstract

Dexmedetomidine activates alpha 2-adrenergic receptors in the central nervous system and in the peripheral vasculature. In vivo dexmedetomidine has been found to cause alterations in coronary and cerebral blood flows and arterial pressure by stimulation of vascular smooth muscle alpha 2 receptors. The direct vasoconstrictor effects of alpha 2-adrenergic agonists may be opposed by release of endothelium-derived relaxing factor believed to be nitric oxide. A functional endothelium was demonstrated recently in canine coronary collateral vessels. The objective of the current study was to assess the direct effect of dexmedetomidine on isolated canine proximal and distal coronary arteries, coronary collateral vessels, and middle cerebral arteries. Responses were measured in tissue baths in the presence of indomethacin 10(-5) M and in the absence and presence of NG nitro-l-arginine methyl ester (L-NAME), an inhibitor of vascular nitric oxide synthesis. Dexmedetomidine (3 x 10(-8) to 3 x 10(-3.9) M) caused constriction (3.9, 5.5, 72.8, and 2.3% for proximal and distal coronary arteries, middle cerebral arteries, and coronary collateral vessels, respectively, expressed as a percentage of KCl-induced contraction) in all vessels. This constriction was enhanced by the presence of L-NAME in all vessels except cerebral arteries. The selective alpha 2-adrenergic antagonist atipamezole (10(-4) M) abolished the response to low but not high concentrations of dexmedetomidine in middle cerebral arteries, proximal coronary arteries, and coronary collateral vessels.(ABSTRACT TRUNCATED AT 250 WORDS)

Author List

Coughlan MG, Lee JG, Bosnjak ZJ, Schmeling WT, Kampine JP, Warltier DC

MESH terms used to index this publication - Major topics in bold

Adrenergic alpha-Agonists
Adrenergic alpha-Antagonists
Animals
Arginine
Cerebral Arteries
Coronary Vessels
Dogs
Female
Imidazoles
In Vitro Techniques
Indomethacin
Male
Medetomidine
NG-Nitroarginine Methyl Ester
Nitric Oxide
Vasoconstriction