Halothane, Isoflurane, and Enflurane MAC in Pregnant and Nonpregnant Female and Male Mice and Rats

Abstract
The MAC [minimum alveolar concentration] of halothane, isoflurane and enflurane was determined using the tail-clamp technique in pregnant female, nonpregnant female and male Swiss Webster mice (n = 216) and Sprague-Dawley rats (n = 112). Mean MAC values (.+-. SD) for halothane, isoflurane and enflurane in mice were 0.95 .+-. 0.07%, 1.34 .+-. 0.10% and 1.95 .+-. 0.16%, respectively; values in rats were 1.03 .+-. 0.04%, 1.46 .+-. 0.06% and 2.21 .+-. 0.08%, respectively, all significantly higher than in mice. Neither the sex of the animals nor whether female animals were pregnant influenced the results.