抄録
Intrathecal administration of local anesthetics causes neural complications that primarily include sensory defect. In the present study, we observed the micromolphological changes in cultured mouse dorsal root ganglion neurons induced by local anesthetics using video-microscopy. Furthermore, the neurotoxic effects of local anesthetics, lidocaine, tetracaine, procaine, and ropivacaine, were compared. Concentrations used were 5, 12.5, 25, and 50 mM. Molphological changes were observed before and 1, 15, 30, and 60 min after the treatment with local anesthetics. Lidocaine at a concentration of 5 mM had no effect on cell morphology during the observation period. 12.5 and 25 mM lidocaine caused cell swelling 30-60 min after treatment. Treatment with lidocaine at a concentration of 50 mM resulted in membrane rupture within 5 min. Tetracaine and procaine at a concentration of 50 mM caused cell swelling, but did not cause the membrane rupture. Less concentrations of these anesthetics had no effect on cell morphology. Ropivacaine at any concentration had no effect. These results indicate that the order of neurotoxic potency is lidocaine>tetracaine, procaine>ropivacaine, which is similar to the results obtained by clinical studies and in vivo experiments. The Optical investigation may be a simple and useful screening of cytotoxicity of drugs. [Jpn J Physiol 55 Suppl:S82 (2005)]
