The effect of sonicated suspensions of phosphatidylserine, phosphatidylethanolamine and phosphatidylcholine injected intravenously on acetylcholine release from the cerebral cortex was investigated in urethane anaesthetized rats. The electroeorticogram was also recorded.
Phosphatidylserine caused a dose dependent, calcium dependent increase in acetylcholine output with no electrocorticografic changes. The increase, 75% peak effect after 150 mg/kg, was abolished by septal lesions and pretreatment with pimozide. Phosphatidylserine had no effect on acetylcholine release from brain slices in vitro.
Phosphatidylethanolamine was approximately half as active as phosphatidylserine and phosphatidylcholine had no effect on acetylcholine output in vivo.
It is concluded that phosphatidylserine exerts an indirect stimulating action on a septio-cortical cholinergic pathway.