Summary of isoflurane MAC measurements (%, mean ± SD) in rats receiving intrathecal aCSF (control) versus rats receiving intrathecal picrotoxin in aCSF. There was no difference between the first and second MAC measurements for any treatment in either group. Post-MK801 MAC was significantly decreased from baseline in both groups. Isoflurane MAC was significantly higher in the picrotoxin animals than the control animals. The ΔMAC was significantly lower in the picrotoxin animals than the control animals