Topical application of l-menthol induces heat analgesia, mechanical allodynia, and a biphasic effect on cold sensitivity in rats

Amanda H. Klein, Carolyn M. Sawyer, Mirela Iodi Carstens, Merab G. Tsagareli, Nana Tsiklauri, Earl Carstens

Research output: Contribution to journalArticlepeer-review

57 Scopus citations

Abstract

Menthol is used in analgesic balms and also in foods and oral hygiene products for its fresh cooling sensation. Menthol enhances cooling by interacting with the cold-sensitive thermoTRP channel TRPM8, but its effect on pain is less well understood. We presently used behavioral methods to investigate effects of topical menthol on thermal (hot and cold) pain and innocuous cold and mechanical sensitivity in rats. Menthol dose-dependently increased the latency for noxious heat-evoked withdrawal of the treated hindpaw with a weak mirror-image effect, indicating antinociception. Menthol at the highest concentration (40%) reduced mechanical withdrawal thresholds, with no effect at lower concentrations. Menthol had a biphasic effect on cold avoidance. At high concentrations (10% and 40%) menthol reduced avoidance of colder temperatures (15 °C and 20 °C) compared to 30 °C, while at lower concentrations (0.01-1%) menthol enhanced cold avoidance. In a -5 °C cold plate test, 40% menthol significantly increased the nocifensive response latency (cold hypoalgesia) while lower concentrations were not different from vehicle controls. These results are generally consistent with neurophysiological and human psychophysical data and support TRPM8 as a potential peripheral target of pain modulation.

Original languageEnglish (US)
Pages (from-to)179-186
Number of pages8
JournalBehavioural Brain Research
Volume212
Issue number2
DOIs
StatePublished - Oct 2010

Keywords

  • Cold pain
  • Hyperalgesia
  • Hypoalgesia
  • Mechanical allodynia
  • Menthol
  • Pain
  • Thermal preference

ASJC Scopus subject areas

  • Behavioral Neuroscience

Fingerprint Dive into the research topics of 'Topical application of l-menthol induces heat analgesia, mechanical allodynia, and a biphasic effect on cold sensitivity in rats'. Together they form a unique fingerprint.

Cite this