Faculty Collaboration Database

Further characterization of the receptor mechanism involved in the antidysrhythmic effect of dexmedetomidine on halothane/epinephrine dysrhythmias in dogs. Anesthesiology 1995 Nov;83(5):1082-9

Date

11/01/1995

Pubmed ID

7486159

DOI

10.1097/00000542-199511000-00022

Scopus ID

2-s2.0-0028789538 (requires institutional sign-in at Scopus site)   30 Citations

Abstract

BACKGROUND: alpha 2 Adrenoceptors in the central nervous system mediate various physiologic processes, including cardiovascular control. Recently, some of these actions have been reported to be mediated by a nonadrenergic receptor, namely an imidazoline receptor. The authors previously reported that dexmedetomidine, a selective alpha 2 agonist, prevents the genesis of halothane-epinephrine dysrhythmias through a central mechanism. Because dexmedetomidine also binds to imidazoline receptors, we performed the current study to examine the precise receptor mechanism involved in the antidysrhythmic property of dexmedetomidine.

METHODS: Adult mongrel dogs were anesthetized with halothane (1.3%) and monitored continuously for systemic arterial pressure and premature ventricular contractions. The dysrhythmogenic dose of epinephrine was defined as the smallest dose producing four or more premature ventricular contractions within 15-s period. We examined the antidysrhythmic action of dexmedetomidine in the presence of two kinds of alpha 2 antagonists, that is, agents that label imidazoline receptors and exert a pharmacologic action through imidazoline receptors (idazoxan and atipamezole) and agents that are nonimidazoline compounds and are lacking in pharmacologic action through imidazoline receptors (rauwolscine and L-659,066). They were given cerebroventricularly.

RESULTS: Idazoxan and atipamezole significantly inhibited the antidysrhythmic action of dexmedetomidine, whereas rauwolscine and L-659,066 did not.

CONCLUSIONS: Because alpha 2 antagonists having imidazoline or imidazole structures inhibited the antidysrhythmic action of dexmedetomidine, and the inhibition produced by the non-imidazoline alpha 2 antagonists was not significant, imidazoline receptors in the central nervous system are more responsible for the antidysrhythmic action of dexmedetomidine than are alpha 2 adrenoceptors.

Author List

Kamibayashi T, Mammoto T, Hayashi Y, Yamatodani A, Takada K, Sasaki S, Yoshiya I

Author

Tadanori Mammoto MD, PhD Associate Professor in the Pediatrics department at Medical College of Wisconsin

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

Adrenergic alpha-Agonists
Adrenergic alpha-Antagonists
Animals
Dioxanes
Dogs
Drug Interactions
Epinephrine
Female
Halothane
Hemodynamics
Idazoxan
Imidazoles
Imidazoline Receptors
Male
Medetomidine
Receptors, Drug
Ventricular Premature Complexes