Assessing peripheral fibers, pain sensitivity, central sensitization, and descending inhibition in Native Americans: main findings from the Oklahoma Study of Native American Pain Risk

Abstract

Native Americans (NAs) have a higher prevalence of chronic pain than other U.S. racial/ethnic groups, but there have been few attempts to understand the mechanisms of this pain disparity. This study used a comprehensive battery of laboratory tasks to assess peripheral fiber function (cool/ warm detection thresholds), pain sensitivity (eg, thresholds/tolerances), central sensitization (eg, temporal summation), and pain inhibition (conditioned pain modulation) in healthy, pain-free adults (N=155 NAs, N=150 non-Hispanic Whites, NHW). Multiple pain stimulus modalities were used (eg, cold, heat, pressure, ischemic, electric), and subjective (eg, pain ratings, pain tolerance) and physiological (eg, nociceptive flexion reflex) outcomes were measured. There were no group differences on any measure, except that NAs had lower cold pressor pain thresholds and tolerances, indicating greater pain sensitivity than NHWs. These findings suggest that there are no group differences between healthy NAs and NHWs on peripheral fiber function, central sensitization, or central pain inhibition, but NAs may have greater sensitivity to cold pain. Future studies are needed to examine potential within-group factors that might contribute to NA pain risk.

Beyond Black vs White: Racial/Ethnic Disparities in Chronic Pain including Hispanic, Asian, Native American, and Multiracial U.S. Adults

“…Of note, our findings regarding population pain prevalence are somewhat at odds with the literature on experimental pain, which often finds Black, Asian, and Hispanic participants to have greater pain sensitivity than Whites [2; 14; 24; 32], while the prevalence of naturally occurring pain in the population is lower. Paradoxically, Native Americans do not seem to have higher pain sensitivity than whites [40], yet they have higher prevalence, as we just described. This pattern of results suggests that findings from experimental pain research may not provide accurate indications of pain disparities in the general population.…”

Conditioned Pain Modulation Effectiveness: An Experimental Study Comparing Test Paradigms and Analyzing Potential Predictors in a Healthy Population

“…Moreover, a study by J.L. Rudy et al [ 37 ] noted that Native Americans had less tolerance to the cold than non-Hispanic whites and that this response could be because the stimulus produces a greater affective response in this group. Although both studies relate the lower tolerance to cold pain and lower CPM response with racial differences, they agree that the affective-motivational dimension of pain can contribute and that these parameters (cold tolerance and CPM response) are dependent on culture, psychosocial influence and the pain belief system.…”

Effects of nicorandil on p120 expression in the spinal cord and dorsal root ganglion of rats with chronic postsurgical pain

“…recently, the prevalence of cPSP has been increasingly regarded as a public health problem; thus, the present study established SMir, simulating the state of cPSP in rats, to explore the potential mechanism of action of nicorandil in relieving pain. The astrocytes in the spinal cord are considered to be the key point for central sensitization (19,20), which is the main mechanism of pain induction (21)(22)(23). astrocytes in the cnS form a highly interconnected network via complexes formed by connexins, such as p120 and cx43 (5,24).…”