Effect of kainic acid and pentetrazole administration on the activity of nitric oxide synthase in the mouse brain

The present study examined ex vivo effect of kainic acid and pentetrazole administration on the activity of nitric oxide synthase (NOS) in the mouse brain. NOS activity was assayed by measuring the formation of [3H] citrulline from [3H]arginine in the homogenates of mouse hippocampus, neocortex and cerebellum. The highest basal activity of the enzyme was found in this latter brain region. Administration of kainic acid (30 mg/kg) increased the NOS activity in all brain regions examined. On the other hand, pentetrazole (60 mg/kg) did not evoke any significant changes in the NOS activity at 5 min after the administration. Only in cerebellum, at 10 min after administration of pentetrazole, the increase in the activity of the enzyme was observed. The obtained results indicate that the two particular convulsants used in this study differ not only in respect of behavioral signs of seizures which they evoke, but also in respect of the effect on mouse brain NOS activity.