Quantitative assessment of tactile allodynia in the rat paw

S. R. Chaplan, F. W. Bach, J. W. Pogrel, J. M. Chung, T. L. Yaksh

Research output: Contribution to journalArticle

4499 Scopus citations

Abstract

We applied and validated a quantitative allodynia assessment technique, using a recently developed rat surgical neuropathy model wherein nocifensive behaviors are evoked by light touch to the paw. Employing von Frey hairs from 0.41 to 15.1 g, we first characterized the percent response at each stimulus intensity. A smooth log-linear relationship was observed, with a median 50% threshold at 1.97 g (95% confidence limits, 1.12-3.57 g). Subsequently, we applied a paradigm using stimulus oscillation around the response threshold, which allowed more rapid, efficient measurements. Median 50% threshold by this up-down method was 2.4 g (1.81-2.76). Correlation coefficient between the two methods was 0.91. In neuropathic rats, good intra- and inter-observer reproducibility was found for the up-down paradigm; some variability was seen in normal rats, attributable to extensive testing. Thresholds in a sizable group of neuropathic rats showed insignificant variability over 20 days. After 50 days, 61% still met strict neuropathy criteria, using survival analysis. Threshold measurement using the up-down paradigm, in combination with the neuropathic pain model, represents a powerful tool for analyzing the effects of manipulations of the neuropathic pain state.

Original languageEnglish (US)
Pages (from-to)55-63
Number of pages9
JournalJournal of Neuroscience Methods
Volume53
Issue number1
DOIs
StatePublished - Jul 1994

Keywords

  • Allodynia
  • Hyperalgesia
  • Hyperesthesia
  • Neuropathy
  • Pain
  • Up-down method
  • Von Frey hairs

ASJC Scopus subject areas

  • Neuroscience(all)

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