Rilmenidine prevents epinephrine-induced arrhythmias in halothane-anesthetized dogs.
Stimulation of central alpha 2-adrenoceptors has been known to prevent epinephrine-induced arrhythmias in halothane-anesthetized dogs. Because recent studies suggested that several physiological processes that were traditionally attributed to activation of alpha 2-adrenoceptors, such as hypotensive action, are mediated through imidazoline receptors (IRs), it may be likely that IRs are involved in the antiarrhythmic action. We investigated the hypotensive effect of rilmenidine, a selective IR agonist (1, 3, and 10 micrograms/kg i.v.), and the antiarrhythmic effects of the drug on epinephrine-induced arrhythmias during halothane anesthesia in dogs. Although the hypotensive effect of rilmenidine was not remarkable in the dose range we tested, rilmenidine increased the arrhythmogenic threshold for epinephrine in a dose-dependent manner during halothane anesthesia, achieving statistical significance at 10 micrograms/kg, the highest dose we examined. These results suggest that rilmenidine prevents epinephrine-induced arrhythmias during halothane anesthesia and that this effect is more potent than its hypotensive action.
Mammoto
T
T
Department of Anesthesiology, Osaka University, Faculty of Medicine, Osaka, Japan.
Kamibayashi
T
T
Hayashi
Y
Y
Takada
K
K
Yamatodani
A
A
Yoshiya
I
I
D000316:Adrenergic alpha-Agonists / Q000627:therapeutic use*; D000769:Anesthesia, Inhalation; D018685:Anesthetics, Inhalation; D000818:Animals; D000959:Antihypertensive Agents / Q000627:therapeutic use*; D001145:Arrhythmias, Cardiac / Q000139:chemically induced* / Q000517:prevention & control*; D004285:Dogs; D004305:Dose-Response Relationship, Drug; D004837:Epinephrine / Q000037:antagonists & inhibitors*; D005260:Female; D006221:Halothane; D054755:Imidazoline Receptors; D008297:Male; D010080:Oxazoles / Q000627:therapeutic use*; D011955:Receptors, Drug / Q000819:agonists / Q000187:drug effects; D000077769:Rilmenidine
D000316:Adrenergic alpha-Agonists; D018685:Anesthetics, Inhalation; D000959:Antihypertensive Agents; D054755:Imidazoline Receptors; D010080:Oxazoles; D011955:Receptors, Drug; D000077769:Rilmenidine; D006221:Halothane; D004837:Epinephrine