Differential sensitivity to the anxiolytic effects of ethanol and flunitrazepam in PKCgamma null mutant mice

Tests of ethanol effects in PKCgamma null mutant mice have indicated that PKCgamma plays a role in initial sensitivity to ethanol-induced sedation, hypothermia, and GABA(A) receptor function and impacts neurochemical pathways mediating anxiety. The present study was undertaken to evaluate whether the decreased sensitivity to ethanol previously observed in these mice generalized to the anxiolytic effects of ethanol. PKCgamma null mutant mice and wild-type controls were tested in the elevated-plus maze, the black/white box, and the mirrored chamber after ethanol (0, 1.0, 1.25, 1.5 g/kg) or flunitrazepam (FNZ) (0, 0.015, 0.03, 0.06 mg/kg). Results indicated that although both genotypes exhibited anxiolytic responses to ethanol in the elevated plus-maze, null mutant mice were less sensitive than wild-type control mice; however, in the black/white box, PKCgamma null mutants were more sensitive than controls to the anxiolytic effects of FNZ. Neither ethanol nor FNZ produced anxiolytic responses in the mirrored chamber for either genotype. These results suggest that PKCgamma differentially mediates anxiolytic responses to ethanol and FNZ and that this relationship interacts with each drug's efficacy in reducing anxiety-related behaviors specific to each of the three mazes.