ANESTHETIC-DEPENDENT PIAL ARTERIOLAR RESPONSE TO ETHANOL

Anesthetic agents are often administered in the presence of ethyl alco hol. both in research and in the clinical setting. The authors tested the hypothesis that anesthetic agents may affect cerebrovascular respo nses to ethanol. A closed cranial window preparation in the rat was us ed to compare the response of pial arterioles to topically applied eth anol (0.01% to 1% vol/vol) in the presence of alpha-chloralose/urethan e (50 and 600 mg/kg, respectively) or halothane (0.5% to 1%) anesthesi a. Heart rate, mean arterial blood pressure, and blood gas levels were maintained stable and within the physiological range throughout each experiment. Ethanol induced significant vasoconstriction in alpha-chlo ralose/urethane-anesthetized animals (multivariate analysis of varianc e (MANOVA), p = 0.039); conversely, ethanol induced significant vasodi lation of the pial arterioles in halothane anesthetized animals (MANOV A, p = 0.017). These responses were significantly different from one a nother (MANOVA, p = 0.001). Thus, the choice of anesthetic agent alter s the cerebrovascular response to ethanol, and care should be taken to ascertain the influence of anesthesia in both research and clinical s ettings.