Objective:To study the effect of EGb761 on
nicotinic transmission in the synapses of the isolated superior
cervical ganglia
of the Wistar rats.Methods:Using intracellular recording technique,the differences of the amplitude of f-EPSP, membrane potential and resistance, depolarization evoked by Ach and Carb,and f-EPSP facilitated in high Ca~2+ Kerb's solution were observed before and after the
isolated ganglia were perfused with EGb761.Results:At the concentrations of 10~-6～10~-3 g/L, EGb761 could inbibit or cancell reversibly the amplitude of the fast excitarory postsynaptic potential(f-EPSP) induced by preganglionic nerve stimulation; the memberane potential and resistance weren't significantly aletred. When perfused with EGb761,EGb761 had no effects on the memberane depolarization evoked by exogenous acetycholine(Ach) and carbachol(Carb),but antagonized the facilitation of high Ca~2+(10 mmol/L) Kerb's solution on the f-EPSP.Conclusion:EGb761 can inhibit reversibly the
nicotinic transmission in the synapses of superior cervical ganglia probably by presynaptic mechanism, relating to the inhibition of the Ca~2+ influx.