Pflügers Archiv

, Volume 442, Supplement 1, pp r193–r194

Sensitivity of sensory axons to lidocaine nerve block in rats

Authors

  • Igor Potočnik
    • Center of Dental Diseases, Dental Department, University Medical Center, Hrtvatski trg 6, 1000 Ljubljana,
  • Martin Tomšič
    • Jozef Stefan Institute, Ljubljana, Slovenia
  • Fajko Bajrović
    • Institute of Pathophysioology, Medical Faculty, Ljubljana, Slovenia
Regular article

DOI: 10.1007/s004240100021

Cite this article as:
Potočnik, I., Tomšič, M. & Bajrović, F. Pflügers Arch (2001) 442: r193. doi:10.1007/s004240100021

Abstract

The aim of the present study was to test the sensitivity of different classes of sensory axons to lidocaine 2 and 4% nerve block. The basic approach was to examine changes in compound action potential (CAP) of A and C axons of the rat sural nerve induced by 2 or 4% lidocaine nerve block in vitro.

CAP in control sural nerves (n = 6 for each experimental group) before nerve block was induced, consisted of the early component (A axons: 0.3 ± 0.02 ms) and the late component (C axons: 12.2 ± 1.14 ms) with peak voltage amplitudes 4.4 ± 1.4 mV and 0.04 ± 0.02 mV, respectively. Lidocaine 2% nerve block completely abolished the amplitude of CAP of C axons and depressed the amplitude of CAP of A axons to about 20 % of control level. Doubled concentration of lidocaine significantly decreased time taken to develop maximal depression of CAP and significantly increased excitation threshold of sensory A axons, but not of sensory C axons. However, 4% lidocaine did not affect the maximal depression of CAP of sensory A axons. These results support the view, that C axons are more sensitive to lidocaine nerve block than A axons. In addition, our results suggest a population of sensory A axons which is non-sensitive to 2% and 4 % lidocaine.

Key words compound action potentiallidocaineperipheral nerveratsensory axons
Download to read the full article text

Copyright information

© Springer-Verlag 2001