Subjects with bulimia nervosa (BN) have been shown to exhibit abnormal satiety responses. Short-term satiety is largely mediated by afferent vagal activity. Activation of afferent vagal fibers has also been found to stimulate a descending pain inhibitory pathway that leads to elevation in somatosensory pain thresholds. Therefore, the study of pain thresholds in BN subjects may lead to a better understanding of afferent vagal function in this disorder. In this preliminary study, pressure pain thresholds were assessed in nine subjects with BN on 3 consecutive days during a binge- eating and vomiting (B/V) episode, during a normal meal, and after an overnight fast. A significant time versus condition effect was found with a significant change in the pain threshold in BN subjects under the B/V condition only. These data are consistent with the hypothesis that vagal afferent activation by a B/V episode also activates the descending pain inhibitory pathway.
Bibliographical noteFunding Information:
Supported by grants from the Minnesota Medical Foundation, Grant No. MO1RROO4OOf rom the National Center for Research Resources, General Clinical Research Center Program, Grant No. 5RO1MH49385 from the National Institute of Mental Health, and Grant No. 5RO1DK52291-04 from the National Institute of Diabetes and Digestive and Kidney Diseases.