[The effect of quaternization on local anesthetic effects of trimecaine]

Effects of the local anaesthetic trimecaine and its quaternary derivative on the isolated rat sciatic nerves were examined. Trimecaine inhibited action potential propagation in the isolated nerve in vitro at four-times lower concentrations than its quaternary derivative. Despite extracellular application, the quaternary derivative inhibited action potential propagation in the sciatic nerve but with a longer half-life in comparison with trimecaine. With increasing external pH, the blocking effect of trimecaine was profound. The blocking potency of the quaternary compound was not consistently changed with the changes in external medium pH.