Spontaneous recurrent seizure induced by KA damages spatial learning and memory as well as dopaminergic neurons in rats

Objective To explore the effects of Spontaneous recurrent seizure(SRS) on Spatial learning memory and dopaminergic neurons of the midbrain in KA treated rats.Methods The rats were injected with a convulsive dose(10 mg/kg,s.c.) of KA to establish an acute seizure model and were selected as the SRS rats according to the scale of Racine in the following 3 weeks.Morris water maze was used to evaluate cognitive function in the animals.We used tyrosine hydroxylase(TH)-immunohistochemistry to measure the immunoreactivity(IR) of the dopaminergic neurons in the midbrain of the rats.Results All KA treated rats were in the stages from 4 to 5 according to the scale of Racine.After 3 weeks,19 KA treated rats showed SRS,but not Morris water maze results showed that during five days of learning memory training and testing,the search latency of KA(treated rats) with SRS was much longer than that of KA treated rats without SRS and saline treated rats significantly(P0.01).In theprobe test,KA treated SRS rats crossed the location of platform only 5 times,which was much less than that of the KA treated rats without SRS and saline treated rats,respectively(P0.01,(P0.01)).TH immunohistochemistry showed that compared with KA treated rats without SRS and saline treated rats,the KA treated SRS rats lost more of TH-IR positive dopaminergic neurons in VTA(P0.01).Conclusion Spatial learning memory deficits could be induced by SRS;the loss of dopaminergic neurons in VTA was associated with the learning memory deficits induced by SRS in KA treated rats.