Evaluation of the mechanisms by which gamma-amino-butyric acid in association with phosphatidylserine exerts an antiepileptic effect in the rat.
The i.p. injection in rats of GABA (740 mg/Kg) after sonication with an equal amount of phosphatidylserine (PS) has an antiepileptic effect. The injection of plain GABA has no such an effect. Blood, brain and synaptosomal accumulation of exogenous labeled GABA under the two circumstances are evaluated. In the case of GABA/PS injection there is a higher passage of the exogenous labeled neurotransmitter into the blood and brain nerve endings (synaptosomes). A higher synaptosomal accumulation of the exogenous labeled neurotransmitter is found even when GABA and PS are injected separately. Since these accumulation increases occur at a time when there is the antiepileptic effect, they seem relevant to it. Our interpretation of the chain of the events resulting in the antiepileptic action is that the phospholipid facilitates from the beginning the first passage of the exogenous neurotransmitter form the peritoneum to the blood. Then a higher passage to the brain tissue and eventually to the GABA-ergic nerve endings ensues. The brisker accumulation of the exogenous neurotransmitter in the nerve endings could be at the basis of a more efficient GABA-ergic inhibitory control in the brain.