Role of striatal acetylcholine and free ammonia in the central stimulatory effects of pp'DDT in rats

pp'DDT (600 mg/kg, orally) produced an increase in the level of free ammonia and a decrease of acetylcholine in the corpus striatum of rats. These effects were maximal 5 h after the administration of pp'DDT. The animals showed tremors after 2 h, mild or moderate convulsions after 3.5 h and severe convulsions 5 h after treatment with pp'DDT. The neurochemical changes and convulsions induced by pp'DDT were modified to different degrees by barbiturates. Phenobarbitone sodium abolished the convulsions while prominal reduced the severity of convulsions in pp'DDT treated animals. The level of striatal acetylcholine in pp'DDT-phenobarbitone treated animals was not significantly different from the control values. In prominal-pp'DDT treated animals, it was slightly but significantly reduced. Primidone neither changed the severity of convulsions nor the level of striatal acetylcholine in pp'DDT treated animals. Further barbiturates had no significant effect on the level of free ammonia in pp'DDT treated rats. The results suggest that changes in the level of acetylcholine are not the cause but an effect of pp'DDT induced stimulatory effects or convulsions, mediated through an increase in the level of free ammonia or some other mechanism.