In vitro effect of Ginkgo biloba extract (EGb 761) on the activity of presynaptic cholinergic nerve terminals in rat hippocampus.

The effects of Ginkgo biloba extract (EGb) applied in vitro to hippocampal synaptosomes from young Wistar rats on the specific binding of [3H]hemicholinium-3 ([3H]HCh-3), high-affinity choline uptake (HACU) and activity of Na+,K(+)-ATPase were examined. EGb at a concentration of 100 micrograms/ml markedly elevated the specific binding of [3H]HCh-3 (to 306%) and moderately elevated HACU values (to 115%). Scatchard analysis revealed an increase in the Bmax for [3H]HCh-3 binding. Lineweaver-Burk analysis an increase in the Vmax for choline uptake. No marked changes in the activity of the sodium pump were discovered. EGb was not able to influence the specific 'second messenger' effect of arachidonic acid.