敌百虫对豚鼠离体颈上神经节突触烟碱传递的影响

应用细胞内生物电记录技术,观察敌百虫对豚鼠离体颈上神经节突触传递过程的影响。敌百虫在0.05μmol/L或更低浓度,可使兴奋性突触后电位及乙酰胆碱除极可逆地增大,但对氨甲酰胆碱除极反应无影响。敌百虫在0.1mmol/L或更高浓度,可使兴奋性突触后电位、乙酰胆碱及氨甲酰胆碱除极可逆地减小;抑制作用在低钙高镁溶液中仍存在。而敌百虫对细胞膜电位、膜电阻无明显影响。实验结果表明,敌百虫对突触传递过程的易化作用是与其抗胆碱酯酶作用有关,而抑制作用则是其对突触后膜直接作用的结果。

THE EFFECTS OF TRICHLORPHON ON NICOTINIC TRANSMISSION IN THE ISOLATED SUPERIOR CERVICAL GANGLIA OF THE GUINEA PIG

The effects of trichlorphon on ganglionic transmission of the isolated superior cervical, ganglia of the guinea pig were investigated by means of intracellular recording techniques. At the concentration of 0.05 μmol/L or less, trichlorphon increased the amplitude and duration of the fast excitatory postsynaptic potential ( f-KPSP ) and the membrane apolarization induced by application of acetylcholine ( ACh), but not carbachol ( CaCh ) . At the concentration of 0.1 mmol/L or more, trichlorphon reversibly depressed the f-EPSP and depolarization evoked by superfusion of either ACh or CaCh. Furthermore, the depressant effect of trichlorphon persisted in a low Ca/ high Mg solution. The membrane potential and membrane resistance of the sympathetic neurons were not significantly altered by trichlorphon. The results indicate that the facilitatory action of trichlorphon appears to be related to its anticholinesterase activity,whereas trich-lorphon-induced blockade of transmission may be explained by a direct action of trichlorphon on the postsynaptic membrane.