Force of limb withdrawals elicited by graded noxious heat compared with other behavioral measures of carrageenan-induced hyperalgesia and allodynia

Etsuo Tabo, John H. Eisele, Earl Carstens

Research output: Contribution to journalArticle

22 Scopus citations

Abstract

We investigated if carrageenan-induced thermal hyperalgesia and mechanical allodynia are associated with a reduction in threshold and-or enhancement of suprathreshold nocifensive responses, using a method to measure the force of a hind limb withdrawal reflex elicited by graded noxious heat stimuli (36-52°C, 5 s) delivered by Peltier thermode tethered to the ventral hind paw of conscious rats. Withdrawal reflexes were recorded 2.5 h after intraplantar injection of carrageenan (1 or 0.1%) or saline vehicle in sessions > 2 weeks apart: baseline reflexes were assessed the day before. Withdrawal reflex force increased linearly from 42-52°C. Carrageenan 1% significantly enhanced withdrawal reflexes at 40-46°C, reducing the slope and threshold of the stimulus-response function. This was associated with significant reductions in thermal paw withdrawal latency (Hargreaves test: by 50%), mechanical withdrawal threshold (by 82%) and weight bearing on the injected side (by 81%) measured with independent force plates. Smaller reductions in thermal paw withdrawal latency and mechanical withdrawal threshold, and smaller enhancement of withdrawal reflex force, were observed following 0.1% carrageenan. Intraplantar saline was ineffective. This method allows assessment of hyperalgesic changes in stimulus-response coding over a broad range of noxious stimulus intensities.

Original languageEnglish (US)
Pages (from-to)139-149
Number of pages11
JournalJournal of Neuroscience Methods
Volume81
Issue number1-2
DOIs
StatePublished - Jun 1 1998

Keywords

  • Allodynia
  • Carrageenan
  • Hyperalgesia
  • Nociception
  • Rat
  • Stimulus-response function
  • Withdrawal reflex

ASJC Scopus subject areas

  • Neuroscience(all)

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