Interaction of glutathione depletion and psychotropic drug treatment in prepulse inhibition in rats and mice

Oxidative stress has been implicated in several psychiatric illnesses, including schizophrenia. Glutathione is the brain's primary antioxidant and decreased levels of brain glutathione are reported in schizophrenia. Prepulse inhibition (PPI) is a measure of sensory gating, and PPI is reduced in schizophrenia. This study aimed to investigate the effects of brain glutathione depletion on PPI regulation. Rats and mice were treated with the glutathione-depleting agent, 2-cyclohexene-1-one (CHX), and tested for baseline PPI and its disruption by treatment with amphetamine and MK-801. Treatment with CHX caused significant depletion of GSH in frontal cortex and striatum of rats and mice. Baseline PPI and startle were not altered. However, the disruption of PPI after treatment with amphetamine was absent in CHX-treated rats. In contrast, the effect of MK-801 was not altered by CHX-treatment, nor was there any effect of CHX treatment in mice. These data show an interaction of glutathione depletion with the effects of amphetamine treatment on PPI in rats. This effect could reflect loss of plasticity in PPI regulation caused by the additive effects of CHX-induced glutathione depletion and additional oxidative stress caused by amphetamine-induced dopamine release. The significance of these results for schizophrenia is discussed. ► Brain glutathione depletion (BGD) did not disrupt baseline prepulse inhibition (PPI) in rats or mice. ► After BGD, amphetamine treatment failed to reduce PPI in rats. ► BGD did not alter the effect of MK-801 treatment on PPI in rats. ► BGD did not alter the effect of either amphetamine or MK-801 in mice. ► BGD may impair dopaminergic modulation of PPI in rats.