Study on Neurotoxicity of Lidocaine

点击翻译按钮获取中文摘要

The purpose of this study is to clarify the mechanism underlying the two types of lidocaine induced irreversible block observed previously in crayfish giant axon. As to the irreversible but not cell death type block was not due to threshold change which was confirmed by measurement of chronaxy in crayfish giant axon before and after lidocaine application. We supposed abrupt and serious damage took place in voltage gated Na channels by lidocaine, but further acknowledgement was not acquired. On the other hand, we considered that the cell death type irreversible block was due to membrane destruction, provably membrane lysis. To examine the provability of membrane lysis induced by lidocaine and other local anesthetics, the ability of hemolysis and the formation of micelle were determined with some local anesthetics and compared to those of detergents. Potency of micelle formation was expressed as critical micelle concentration (CMC) measured by dye solubilization method. Degree of hemolysis was determined as 90% hemolytic concentration (ECィイD290ィエD2) in vitro. CMC was measured with all test anesthetics except for bupivacaine. ECィイD290ィエD2 values were 1/2-1/5 of CMC with local anesthetics and this relation was same with detergents (hexadecyl trimethyl ammonium C1, Triton-X100), which means that the local anesthetics and detergents affects erythrocyte membrane in same manner, that is membrane lysis.