GABAA receptor antagonism increases NMDA receptor inhibition by isoflurane at a minimum alveolar concentration

A smaller MK801 MAC-sparing effect in the picrotoxin group is consistent with greater NMDA antagonism by isoflurane in these animals, since it suggests that fewer NMDA receptors are available upon which MK801 could act to decrease isoflurane MAC. Decreasing isoflurane GABAA potentiation increases isoflurane NMDA antagonism at MAC. Hence, the magnitude of an anesthetic effect on a given channel or receptor at MAC may depend upon effects at other receptors.