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

从家蝇中枢神经系统分离神经元，分别在M3培养基、LM 3培养基、改良Schneicder培养基和IPL 41培养基中培养。观察存活时间、轴突是否伸长及伸长程度、轴突开始伸长的时间。在轴突伸长的各个方面，这些培养基之间没有观察到明显的差异，但轴突的伸长和存活时间在M3/IPL 41培养基和LM 3培养基中相对较好。在高细胞密度下，培养细胞活率下降至20-30%。成功病例存活期均在90天以上，最长达130天。iusulin加入培养液中对神经细胞的存活期和轴突伸长有明显的促进作用，而丝氨酸、谷氨酸和胎牛血清则无此作用。结果表明，西印度米种子乙酸乙酯提取物具有明显的杀虫活性，其EC_（50）值为43.7 μ g/ml。该部分在0.42 μ g/mL时不可逆地抑制GABA诱导的电流<-1>。Sikimi提取物降低了GABA对GABA受体结合位点的亲和力，从而抑制GABA诱导的电流。从一种热带薯蓣根茎中提取的9，4-十八碳二烯酸对小菜蛾幼虫具有拒食作用，同时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碱和薯蓣碱N-氧化物，用全细胞膜片钳法证明是乙酰胆碱受体通道的开放性阻断剂。

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.