Inter-Individual Variability In Pain Among Healthy African Volunteers: Experimental Evidence

BACKGROUND: Pain, either clinical or experimental, is characterised by a high degree of inter- individual variability, associated with environmental, physiological and genetic factors. This study was designed to investigate sex and ethnic differences in pain perception and the roles of serum glutamate and serotonin concentrations on experimental pain responses among healthy Nigerian adult population. METHODS/SUBJECTS: One hundred and sixty-one (161) apparently healthy volunteers between the ages of 20 to 65 years were recruited for the study. Experimental pain was induced using ischaemic pain tests and pressure pain. Glutamate and serotonin were analysed in serum by ELISA. RESULTS The result showed that experimental pressure and ischaemic pain thresholds were significantly higher in males than in females. Male subjects were found to have lower serum glutamate concentration than females. Serum glutamate concentration was found to correlate positively with pressure pain threshold, while serum serotonin concentration was found to correlate negatively with ischaemic pain tolerance. CONCLUSION: Perception of experimentally induced pressure and ischaemic pain among healthy adult Nigerian subjects showed variation by sex. There is a positive correlation between serum glutamate and experimental pressure pain threshold, and a negative correlation between serum serotonin and experimental ischaemic pain tolerance.