IN-VITRO EFFECT OF GINKGO-BILOBA EXTRACT (EGB-761) ON THE ACTIVITY OFPRESYNAPTIC CHOLINERGIC NERVE-TERMINALS IN RAT HIPPOCAMPUS

The effects of Ginkgo biloba extract (EGb) applied in vitro to hippoca mpal synaptosomes from young Wistar rats on the specific binding of [H -3]hemicholinium-3 ([H-3]HCh-3), high-affinity choline uptake (HACU) a nd activity of Na+,K+-ATPase were examined. EGb at a concentration of 100 mu g/ml markedly elevated the specific binding of [H-3]HCh-3 (to 3 06%) and moderately elevated HACU values (to 115%). Scatchard analysis revealed an increase in the B-max for [H-3]HCh-3 binding, Lineweaver- Burk analysis an increase in the V-max for choline uptake. No marked c hanges in the activity of the sodium pump were discovered. EGb was not able to influence the specific 'second messenger' effect of arachidon ic acid.