[Suppressive effect of methylparaben on the evoked compound action potentials in excised rabbit cervical vagus nerve]

We evaluated the effects of methylparaben on rabbit vagus nerve by measuring the amplitudes and latencies of the evoked compound action potentials during incubation in 0.1% methylparaben containing Ringer's bicarbonate solution. We also evaluated the histological changes of the nerves after incubation in methylparaben-RB solution by means of the electron microscopy. We found that 0.1% methylparaben caused complete suppression of the compound action potentials, which recovered completely after washing in methylparaben-free RB solution. The electron microscopic studies revealed no histological changes of nerves incubated in 0.1% methylparaben containing RB solution. We conclude that methylparaben suppresses nerve excitability dose-dependently, but does not destroy nervous tissues in concentrations up to 0.1%.