CHOLINERGIC ACTIVATION OF PHOSPHOINOSITIDE METABOLISM DURING SOMAN-INDUCED SEIZURES

IN the present study we investigated the role of the cholinergic pathw ay in phosphoinositide metabolism activation observed during soman-ind uced convulsions. We thus studied the effect of atropine sulphate, a m uscarinic antagonist (20 mg kg-1, ip.), on IP3 levels in rat hippocamp us. We demonstrated that initially, the increase of IP3 is closely sei zure-related. On the other hand, after 10 min of seizures, the IP3 enh ancement and the seizure activity are no longer correlated. After 20 m in of seizures, atropine failed to inhibit soman-induced IP3 enhanceme nt, suggesting that the activation of another neurotransmitter system( s) linked to PPI turnover succeeds the cholinergic stimulation.