Halothane attenuates small arteriole vasodilation to serotonin (5-HT) in skeletal muscle.
Inhaled anesthetics may have an effect on the microcirculation through selective alteration of receptor-mediated control. Halothane was chosen because its actions in the microcirculation have been determined previously. Serotonin has received recent attention as a potential mediator of vascular changes in a number of disease states. We obtained concentration-response curves for serotonin-induced constriction of large arterioles and dilation of small arterioles (less than 60 microns diameter) in the cremaster muscle of halothane-anesthetized and decerebrate rats. Cremaster muscles were prepared for microscopic viewing, leaving the neural and vascular supply intact. Serotonin concentration-response curves were obtained before and after receptor antagonist application. Large arteriole constriction was not affected by halothane. Dilation of small arterioles was decreased in halothane-anesthetized animals but enhanced in the presence of methysergide, a nonspecific antagonist. These data indicate that halothane interferes with occupancy of 5-hydroxytryptamine receptors.
Asher
E F
EF
Department of Anesthesia, School of Medicine, University of Louisville, KY 40292.
Alsip
N L
NL
Zhang
P Y
PY
Harris
P D
PD
D000818:Animals; D001160:Arterioles / Q000187:drug effects* / Q000502:physiology; D004305:Dose-Response Relationship, Drug; D004873:Ergolines / Q000494:pharmacology; D006221:Halothane / Q000494:pharmacology*; D008297:Male; D008784:Methysergide / Q000494:pharmacology; D009132:Muscles / Q000098:blood supply*; D009569:Nitric Oxide / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains; D012701:Serotonin / Q000494:pharmacology*; D014664:Vasodilation / Q000187:drug effects*
D004873:Ergolines; D009569:Nitric Oxide; D012701:Serotonin; C032663:LY 53857; D006221:Halothane; D008784:Methysergide