呲虫啉、杀虫双对美洲蜚蠊中枢神经的电生理影响

本文运用美洲蜚蠊(Periplaneta americana)第V1腹神经节突触后电位细胞外记录方法研究了吡虫啉、杀虫双对中枢神经活动的影响。结果显示：1.73x10^-7mol/L吡虫啉和 1.38XlO^-5Stool/L杀虫双处理后初期均能引起自发性突触后电位发放增强，随后导致突触传递阻断。而吡虫啉较杀虫双阻断传递快，且用Ringer生理溶液冲洗不易恢复，表明吡虫啉较杀虫双激动剂活性更强。以3.37×10^-5mol/L甲胺磷预处理中枢神经样品后，再进行杀虫双处理，则突触后电位的发放频率和幅值有明显增强，产生连续超幅排放(overshooting)现象，相反，甲胺磷预处理对随后进行吡虫啉处理无明显影响。这些结果说明，吡虫啉、杀虫双和乙酰胆碱受体发生相互作用过程存在差异。

NEUROPHYSIOLOGICAL EFFECTS OF IMIDACLOPRID AND DIMEHYPO ON THE CENTRAL NERVOUS SYSTEM IN THE AMERICAN COCKROACH, PERIPLANETA ARMERICANA

Effects of the insecticides lmidacloprid and Dimehypo on the postsynaptic potential at the cercal-giant fiber synapses located with in the sixth adbominal ganglion of the American cockroach Periplaneta americana were studied by using extracellular electrophysiological recording method. An initial increase in thefrequency of spontaneous postsynaptic potentials and final complete block to the impulse propagation were observed after the application of Imidacloprid (1.73 ×10_-7mol/l) or Dimehypo (1.38×10^-5 mol/L). Blocking action caused by Imidaclopridwas quicker than by Dimehypo, and recovery is more difficult in the normal Ringer solution. It is supposed that the agonistic activity of Imidacloprid is stronger than that of Dimehypo. When a pre-application of Methamidophos (3.37×10^-5mol/L) was conducted, treatment with Dimehypo produced greatly increased spontaneouspostsynaptic firings and high frequency bursts of overshooting. By contrast, no visible changes were brought to the Imidacloprid treatment by Methamidophos pre-application. This study shows that there is some pharmacological difference between Imidacloprid and Dimehypo during their interactions with the postsynaptic acetylcholine receptors.