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BioMed Research International
Volume 2014, Article ID 540238, 9 pages
http://dx.doi.org/10.1155/2014/540238
Research Article

Effects of Various Antiepileptics Used to Alleviate Neuropathic Pain on Compound Action Potential in Frog Sciatic Nerves: Comparison with Those of Local Anesthetics

1Department of Physiology, Saga Medical School, Saga 849-8501, Japan
2Department of Anesthesiology & Critical Care Medicine, Saga Medical School, Saga 849-8501, Japan

Received 3 October 2013; Revised 24 December 2013; Accepted 7 January 2014; Published 24 February 2014

Academic Editor: James Stockand

Copyright © 2014 Yuhei Uemura et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Antiepileptics used for treating neuropathic pain have various actions including voltage-gated Na+ and Ca2+ channels, glutamate-receptor inhibition, and -receptor activation, while local anesthetics are also used to alleviate the pain. It has not been fully examined yet how nerve conduction inhibitions by local anesthetics differ in extent from those by antiepileptics. Fast-conducting compound action potentials (CAPs) were recorded from frog sciatic nerve fibers by using the air-gap method. Antiepileptics (lamotrigine and carbamazepine) concentration dependently reduced the peak amplitude of the CAP ( and 0.50 mM, resp.). Carbamazepine analog oxcarbazepine exhibited an inhibition smaller than that of carbamazepine. Antiepileptic phenytoin (0.1 mM) reduced CAP amplitude by 15%. On the other hand, other antiepileptics (gabapentin, sodium valproate, and topiramate) at 10 mM had no effect on CAPs. The CAPs were inhibited by local anesthetic levobupivacaine (  mM). These results indicate that there is a difference in the extent of nerve conduction inhibition among antiepileptics and that some antiepileptics inhibit nerve conduction with an efficacy similar to that of levobupivacaine or to those of other local anesthetics (lidocaine, ropivacaine, and cocaine) as reported previously. This may serve to know a contribution of nerve conduction inhibition in the antinociception by antiepileptics.