STUDIES ON INSCT NEUROCELL CULTURE AND MODE OF ACTION OF NEUROTOXIC COMPOUNDS

将家蝇中枢神经系统神经元分别培养于M3培养基、LM3培养基、改良施耐德培养基和IPL41培养基中。观察存活期、轴突伸长是否发生及其程度、轴突伸长开始前的存活期。不同培养基在轴突伸长各方面均无明显差异，但M3/IPL41培养基和LM3培养基的轴突伸长和活期较好。细胞密度高时，培养细胞存活率下降至20-30%。成活期90天以上，最长可达130天。在培养基中掺入胰岛素对神经轴突伸长和神经细胞存活期有积极影响，而在丝氨酸、谷氨酸和胎牛血清中掺入胰岛素则无明显影响。四叶草种子乙酸乙酯提取物具有良好的杀虫活性，EC50值为43.7mugml-1。该分数在0.42 mugml_<-1>时不可逆地抑制gaba感应电流。五味子提取物降低GABA对GABA受体结合位点的亲和力，从而抑制GABA诱导的电流。从热带山药根茎中提取的9,4-十八二烯酸对小菜蛾幼虫具有拒食作用，对小菜蛾幼虫也有较强的杀虫活性。从山药中分离得到的薯蓣皂苷和薯蓣皂苷n -氧化物是乙酰胆碱受体通道的开放通道阻断剂。

Neurons cerived from the central nervous system of housefly was cultured in M3 medium, LM3 medium, modified Schneicder's medium and IPL41 medium. The viable term, whether axon elongation was occurred or not and its extent, the term till the beginning of axon elongation were examined. No distinct differences were observed among these media on the various aspects in an axon elongation, but axon elongation and viable term were comparatively better in M3/IPL41 medium and LM3 medium. The ratio of viable culture cell fell off to 20-30% at high density of cell. The viable term was over 90 days in successful case, the longest was 130 days. Positive effect in axon elongation and the viable term of nervous cell was observed when iusulin was incorporated into media but not in serine, glutamic acid and fetal bovine serum. Ethylacetate extract of Sikimi seeds was insecticidally active, with EC50 values of 43.7mugml-1. This fraction suppressed GABA-induced currents irreversibly at 0.42 mugml_<-1>. Sikimi extracts decreased the affinity of GABA for its binding site on the GABA receptor, thereby suppressing GABA-induced currents. From rhizome of a tropical yam, 9,4-octadecadienoic acid was identified as a antifeedant to the Diamondback moth larvae and it also showed potent insecticidal activity to the larvae. Dioscorine and dioscorine N-oxide, which were isolated from the yam, were shown to be an openchannel bocker of acetylcholin receptor channel by a whole cell patch clump method.