Ethnic disparities in pain processing among healthy adults: μ-opioid receptor binding potential as a putative mechanism. Issue 4 (April 2020)

• Record Type: Journal Article
• Authors: Letzen, Janelle E.; Mun, Chung Jung; Kuwabara, Hiroto; Burton, Emily F.; Boring, Brandon L.; Walls, Taylor; Speed, Traci J.; Wong, Dean F.; Campbell, Claudia M.
• Is Part Of: Pain. Volume 161:Issue 4(2020)
• Publication Date: 2020-04
• Subjects: Ethnic differences -- Endogenous pain modulation -- Mu-opioid receptors -- [11C]-Carfentanil -- PET -- Neuroreceptor imaging; Pain -- Periodicals; Douleur -- Périodiques; Anesthésie -- Périodiques; Pain; Electronic journals; Periodicals; Electronic journals; 616.0472
• DOI: 10.1097/j.pain.0000000000001759
• Languages: English
• ISSNs: 0304-3959

Abstract

Abstract : Abstract: Although ethnic differences in pain perception are well documented, the underlying mechanism for these outcomes has not been established. µ-opioid receptor (MOR) function might contribute to this disparity, given that MORs play a key role in pain sensitivity and modulation. However, no study has characterized ethnic differences in MOR physiology. This study sought to address this knowledge gap by examining differences in µ-selective agonist binding potential (BPND ; [ 11 C]-Carfentanil) between 27 non-Hispanic black (NHB) and 27 demographically similar, non-Hispanic white participants. Participants completed questionnaires and two 90-minute high-resolution research tomograph positron emission tomography (PET) imaging sessions. During PET imaging, a capsaicin or control cream was applied to individuals' arms, and pain ratings were collected. Bonferroni-corrected PET volumes of interest analyses revealed significantly greater [ 11 C]-Carfentanil BPND among NHB participants in bilateral ventral striatum ([left]: F1, 52 = 16.38, P < 0.001; [right]: F1, 52 = 21.76, P < 0.001), bilateral dorsolateral prefrontal cortex ([left] F1, 52 = 17.3, P < 0.001; [right]: F1, 52 = 14.17, P < 0.001), bilateral subgenual anterior cingulate cortex ([left]: F1, 52 = 10.4, P = 0.002; [right]: F1, 52 = 12.91, P = 0.001), and right insula (F1, 52 = 11.0, P = 0.002). However, there were no significant main effects of condition or ethnicity × condition interaction effects across models, likely attributable to individual variability in the direction of change within groups. BPND values were significantly correlated with pain ratings collected during the capsaicin condition ( r range = 0.34-0.46, P range = 0.01-0.001). Results suggest that NHB individuals might have generally greater unoccupied MOR density than non-Hispanic white peers. Findings have implications for physiological differences underlying ethnicity-related pain disparities. If replicated, these results further emphasize the need for tailored treatments in historically underserved populations. Abstract : Supplemental Digital Content is Available in the Text.Ethnic pain disparities are robustly observed. Our findings highlighted differences between non-Hispanic black and white adults in mu-opioid binding, a potential mechanism of such disparities.