Effects Of Egb On The Bioelectric Activiyty And Synaptic Transmission Of The Neurons In Celiac Ganglia Of Guinea-Pig In Vitro

Using the intracellular recording technique and the administration of super-fusion, this work was going to investigate the effects of EGb and Flavonoids on bioelectric and synaptic transmitted of the neurons in celiac ganglia of guinea-pig in vitro. Eventually we hope to discover how EGb and its active composes will do on the sympathetic ganglia. The main experimental results are as follows: 1. The bioelectric effects of EGb on the neurons of CG1.1 The mean of resting potential of CG cell in guinea-pig is -50.5\2.5mV(n=200) and the membrane resistance 55.2 ± 3.8M .1.2 Superfusion of celiac ganglia with EGb(50~500mg/L) evoked a concentration-dependent membrane depolarization in the majority(75.0%) of the neurons(n=44), with the mean amplitude and the average duration are 5.6\0.8mV and 240.7\50Sec respectively. Among the cells tested, 12.5% of the cells was induced hyperpolarization and 6.3% biphasic response which consisted of an initial hyperpolarization phase and a followed depolarization. There are also 6.3% of the cells observed which show both depolarization and hyperpolarization at the different time under the same conditions. The neurons Rm could be changed during the depolarization accured with 33.8% of the cells decreased, 26.2% increased and unchanged in the rest 40.0%. These results imply that the EGb has complicated effects on the neurons of CG.1.3 Depolarizations of EGb could not be affected by cholinocepor and adrenoceptor inhibitors (n=8). Depolarizations of EGb could be blocked partially by low Ca2±/high Mg2"1" solution (n=7).2. The bioelectric and synaptic transmission effect of Flavonoids and the possiblemechanism2.1 Superfiision of celiac ganglia with Flavonoids (10~100mg/L) evoked the same effects as EGb did (n=120) on CG neurons. Among these cells 55(45.8%) presented depolarization , 12(10.0%) biphasic response and 41(34.2%) no responses. The average amplitude and duration of depolarization caused by Flavonoids are 7.9\0.7mv and 245.6 \29.2Sec, respectively. The depolarization effects caused by Flavonoids also has the character of concentration-dependent. The results above suggest that the effects of EGb on CG neurons is mainly caused by Flavonoids.2.2 Superfusion of celiac ganglia with 10-4 mol/L cholinoceptor (Atropine and Hexamethonium )and adrenoceptor inhibitor (Phentolamin and Propranolo) had no effects on the depolarization evoked by Flavonoids; Superfusion of celiac ganglia with Low Ca2±/High Mg2"1" solution, the depolarization caused by Flavonoids would be attenuated.2.3 Among 42 of the depolarization cells, the Rm could be decreased by 18.2\ 2.5% in 46.7%(n=27), unchanged in 30.0%, increased by 26.7\6.7 in the rest 23.3%. These results reveal that more than one kind of ion involves in the depolarization. Substituting Na* with NMG and then Superfusion of celiac ganglia with this Na± free solution would attenuate the depolarization caused by Flavonoids; Substituting Ca± with BaCl2 then superfusion of celiac ganglia with this Ca2± free solution would attenuate the depolarization caused by Flavonoids; Superfusion of celiac ganglia with K± inhibitor TEA, would augment the amplitude of depolarization caused by Flavonoids; These result suggest that Na± Ca2± K* are all the possible ions which involves in the depolarization induced by Flavonoids. The amplitude of depolarization evoked by Flavonoids changed as the membrane potential were controlled at different level (n=10). The depolarizations were attenuated in the majority cells (80%) when membrane potential decreased. The reversal potential for the event was about -30mV. These data futher elucidate that several kinds of ions , including Na\ Ca2±> K±, contribute to the formation of depolarization of Flavonoids.2.4 f-EPSP was initiated by stimulating left lesser splanchnic nerve with currentpulses. Then superfusion of celiac ganglia with Flavonoids (10~100ug/ml) would converted subthreshold PSP to action potentials, The effects...