ISOFLURANE ISOMERS DIFFER IN PRESERVATION OF ATP IN ANOXIC RAT HEPATOCYTES

The volatile anesthetic isoflurane inhibits the precipitous drop of AT P concentration that results from induced anoxia in isolated rat hepat ocytes. This change is dose dependent and reaches its maximum at clini cally relevant anesthetic concentrations. The use of highly purified i soflurane enantiomers has allowed a demonstration of the difference in the efficacy of the (+) and (-) isomers on the isoflurane-dependent p reservation of ATP. The difference in relative potency between isomers was approximately 2.5-fold, with the (-) form being more potent. In a direct test of the anesthetic potency of these isomers, it was shown previously that the (+) isomer was more potent than the (-) isomer. Di fferences in the order of potency of isoflurane stereoisomers for the ''anesthetic'' and ''metabolic'' effects of isoflurane suggest that th ese effects are independent and may result from interactions with diff erent specific molecular sites.