Elsevier

The Journal of Pain

Volume 9, Issue 8, August 2008, Pages 759-766
The Journal of Pain

Original report
Ethnic Differences in Diffuse Noxious Inhibitory Controls

https://doi.org/10.1016/j.jpain.2008.03.010Get rights and content
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Abstract

Substantial evidence indicates that the experience of both clinical and experimental pain differs among ethnic groups. Specifically, African Americans generally report higher levels of clinical pain and greater sensitivity to experimentally induced pain; however, little research has examined the origins of these differences. Differences in central pain-inhibitory mechanisms may contribute to this disparity. Diffuse noxious inhibitory controls (DNIC), or counterirritation, is a phenomenon thought to reflect descending inhibition of pain signals. The current study assessed DNIC in 57 healthy young adults from 2 different ethnic groups: African Americans and non-Hispanic whites. Repeated assessments of the nociceptive flexion reflex (NFR) as well as ratings of electrical pain were obtained before, during, and after an ischemic arm pain procedure (as well as a sham procedure). The DNIC condition (ie, ischemic arm pain) produced substantial reductions in pain ratings as well as electrophysiologic measures of the NFR for all participants when compared with the sham condition (P < .001). The DNIC condition produced significantly greater reductions in verbal pain ratings among non-Hispanic whites when compared with African Americans (P = .02), whereas ethnic groups showed comparable reductions in NFR. The findings of this study suggest differences in endogenous pain inhibition between African Americans and non-Hispanic whites and that additional research to determine the mechanisms underlying these effects is warranted.

Perspective

This study adds to the growing literature examining ethnic differences in experimental pain perception. Our data suggest that these variations may be influenced by differences in descending inhibition.

Key words

Experimental pain
diffuse noxious inhibitory controls
nociceptive flexion reflex
ethnic differences

Cited by (0)

Supported by NIH/NINDS grant NS42754, General Clinical Research Center Grant RR00082, and T32 MH75884.