Elsevier

The Journal of Pain

Volume 12, Issue 7, July 2011, Pages 764-773
The Journal of Pain

Original Report
Topical High-Concentration (40%) Menthol—Somatosensory Profile of a Human Surrogate Pain Model

https://doi.org/10.1016/j.jpain.2010.12.013Get rights and content
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Abstract

Cold hyperalgesia is 1 of the characteristic signs in neuropathic pain. Topical application of menthol has been proposed as model to study cold hyperalgesia. The aim of this psychophysical study was to characterize the human surrogate of neuropathic pain of topical menthol application by using a standardized and validated protocol of quantitative sensory testing (QST). Additionally, we assessed the course of the signs elicited by menthol application over time. High-concentration 40% L-menthol was applied topically on hairy skin in 12 healthy subjects. Standardized psychophysical tests (QST) assessing 13 parameters including thermal and mechanical detection and pain thresholds were obtained before and every 45 minutes after menthol removal up to 4 hours after menthol application. Menthol decreased the cold pain threshold, mechanical pain threshold, and increased the mechanical pain sensitivity in all subjects displaying cold and mechanical pinprick hyperalgesia. In all subjects, an area of secondary pinprick hyperalgesia could be determined. Within the observation time, the decreased cold pain threshold increased continuously, whereas the signs of primary and secondary pinprick hyperalgesia remained stable. The data suggest that topical 40% menthol application is a useful model for studies of cold hyperalgesia and pinprick hyperalgesia in humans.

Perspective

This study establishes the topical application of high-concentration 40% menthol as a useful stable model for studies of cold hyperalgesia and pinprick hyperalgesia in humans. The provided long-term data are important for psychophysical and pharmacological research in humans and provide us with insights on experimental cold and mechanical hyperalgesia.

Key words

Cold hyperalgesia
mechanical hyperalgesia
quantitative sensory testing
model stability

Cited by (0)

This study is a part of the Europain project, funded by the Innovative Medicines Initiative Joint Undertaking (IMI JU; www.imi.europa.eu) Grant no 115007 and was financially supported by BMBF (01EM0504) and an unrestricted financial grant from Pfizer Germany.

A.B. received honoraria for lectures from Grünenthal, Allergan, Astellas, Pfizer and payment for development of educational presentations from Pfizer. M.S. received honoraria for lectures from Grünenthal and Pfizer. R.B. has consultancies with and received honoraria from Pfizer, Genzyme, Grünenthal, Mundipharma, Allergan, Sanofi Pasteur, Medtronic, Eisai, UCB, Lilly, and Astellas; received grants from Pfizer, Grünenthal, Genzyme; and received payment for development of educational presentations from Pfizer, Medtronic. G.W. received honoraria for lectures from Grünenthal, Medtronic, Pfizer, and Mundipharma.

The authors declare that the sources of financial support had no influence on data assessment, analysis and interpretation and disclose potential conflicts of interest.