Abstract
Sodium bisulfite is clinically used as preservative agent for local anesthetics for epidural anesthesia. Some investigators indicate that sodium bisulfite deteriorates local neurotoxicity, while others indicate that it could decrease local neurotoxicity. Previously we reported that the axon of posterior root is most sensitive to local neurotoxicity. Therefore, we examined whether sodium bisulfite increases or decreases local neurotoxicity by estimating axonal flow in cultured mouse dorsal ganglion neurons.I. To determine the uneffective dose of sodium bisulfite on axonal flow, we added either of 0.1 mM, 1 mM, 10 mM, or 20 mM of sodium bisulfite to the axon. Consequently, more than 10 mM sodium bisulfite suppressed the axonal flow and allow the axon to swell, while 0.1 mM of it did not significantly suppress the flow.II. To investigate whether 0.1 mM sodium bisulfite has synergistic effect with local anesthetics, we compared axonal flow after treatment with 1mM procaine alone, 0.1 mM sodium bisulfite alone, and 1 mM procaine plus 0.1mM sodium bisulfite. Consequently, 1mM procaine alone, and 0.1m M sodium bisulfite alone showed 70-80% suppression of axonal flow, while the mixed solution showed 50-60% suppression.The results indicate that sodium bisulfite dose-dependently suppresses axonal flow and may increases local neurotoxicity. [J Physiol Sci. 2008;58 Suppl:S152]
