MOTOR EXPRESSION OF KAINIC ACID SEIZURES IS ATTENUATED BY DOPAMINE DEPLETION IN MICE

We studied the effect of striatal dopamine depletion induced by 1-meth yl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) in mice on kainic acid ( KA) evoked seizures. MPTP, 36 mg/kg i.p. for 3 days, caused an 80% dro p of striatal dopamine. Animals pretreated with MPTP, plus controls tr eated with saline, were challenged with five different convulsant dose s of KA (3, 6, 12, 18 and 35 mg/kg i.p.). The seizures were monitored by electrographic recording and behavioral observation. MPTP pretreatm ent greatly attenuated the severity of the convulsions and the mortali ty induced by KA. The effect was mostly evident at the intermediate an d at the high doses of KA. Surprisingly, no differences between the MP TP and control groups were found on the intensity and time course of t he electrical seizures. Increment doses of KA resulted in a more sever e electrographic seizure pattern in both the saline and the MPTP pretr eated groups. Our data suggest that the dopamine depletion induced by MPTP does not alter the genesis of KA induced seizures, but may alter the function of cerebral structures involved in the control of seizure motor expression.