Effects of stress and etifoxine on pentobarbital-induced loss of righting reflex in Balb/cByJ and C57BL/6J mice.

We hypothesized that functional changes in the GABAergic system induced by stress would differ between two inbred mouse strains BALB/cByJ and C57BL/6J. We compared the effects of restraint stress and of the anxiolytic drug etifoxine (EFX) on the duration of pentobarbital-induced loss of righting reflex (hypnotic effect) in the two strains. Naive BALB/cByJ mice were less sensitive than naive C57BL/6J mice to the hypnotic effect of pentobarbital. C57BL/6J mice exhibited a shortening in the duration of pentobarbital-induced hypnosis following stress whereas stress had no effect in BALB/cByJ mice. EFX reversed the shortening of pentobarbital-induced hypnosis elicited by stress in C57BL/6J and shortened the duration of pentobarbital-induced hypnosis after stress in BALB/cByJ mice. Alterations in the GABAergic function in BALB/cByJ mice could be corrected by EFX, an enhancer of GABAergic transmission.