Pflügers Archiv

, Volume 442, Supplement 1, pp r193–r194 | Cite as

Sensitivity of sensory axons to lidocaine nerve block in rats

  • Igor Potočnik
  • Martin Tomšič
  • Fajko Bajrović
Regular article


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 potential lidocaine peripheral nerve rat sensory axons 

Copyright information

© Springer-Verlag 2001

Authors and Affiliations

  • Igor Potočnik
    • 1
  • Martin Tomšič
    • 2
  • Fajko Bajrović
    • 3
  1. 1.Center of Dental Diseases, Dental Department, University Medical Center, Hrtvatski trg 6, 1000 Ljubljana,
  2. 2.Jozef Stefan Institute, Ljubljana, SloveniaSI
  3. 3.Institute of Pathophysioology, Medical Faculty, Ljubljana, SloveniaSI

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