The Effects Of EGb761 On Nicotinic Transmission In The Isolated Superior Ganglia Of The Wistar Rats

Object: To study the effects of EGb761 on nicotinic transmission in the isolated superior ganglia of the Wistar rats. Method: Intracellular recording technique. Results: At the concentractions of 10-6~10-1g/L for 1~10minutes, EGb761 can reduced or cancelled the amplitude of the fast excitarory postsynaptic potential(f-EPSP) induced by the single stimulation of the preganglionic sympathetic trunk (n=42),with the memberane potentials of 38 cells unchanged and the memberane of 4 cells depolarized moderately; When the memberane potentials return to the base line,the inhibition effects of EGb761 on f-EPSP still existed.During the 1~10 minutes of perfusion with EGb761(10-6~10-1g/L, n=24),the memberane potentials of 21 cells weren't alerted,two cells has slight depolarization,and one depolarized after hypolarized. When perfused with EGb761(2.0~3.5×10-1g/L,n=10), 7 cells depolarized moderately,2 cells unchanged, and one hypolarized. The memberane resistance were not significantly alerted at both concentrations. EGb761 have no effects on the depolarization by exogenous acetycholine(Ach) and carbachol(Carb). EGb761(10-1g/L) antagonized the facilitation of high Ca2+(5mmol/L) Kerb's solution on the f-EPSP, and enhanced the depressant effect of low Ca2+ Kerb's solution.Conclusion:EGb761 can inhibited reversedly the nicotinic transmission at superior cervical ganglia probably by presynaptic mechanism, relating to the inhibition of the Ca2+ influx...