Effect of somatovisceral reflexes and selective dermatomal stimulation on postcibal antral pressure activity

Our objective was to elicit and characterize somatogastric reflexes in healthy humans. Sustained somatic stimulation by transcutaneous electrical nerve stimulation (TENS) was applied to the skin of human volunteers while simultaneously monitoring their upper gastrointestinal phasic pressure activity, extraintestinal vasomotor indices, and plasma levels of putative humoral mediators of autonomic reflexes. Stimuli were applied either to the hand (C8-T1) or to the upper abdomen (T5-T10) to determine whether impulses at these two dermatomes produce different effects on fed antral phasic pressure activity. TENS resulted in significant reduction (P = 0.007) in antral motility index when applied to the hand and abdomen as compared with sham stimulation. This was associated with an increase in skin conductance and plasma beta-endorphin levels but no change in pulse, blood pressure, or circulating catecholamine levels. No qualitative changes in proximal intestinal pressure activity were detected. Sustained somatic stimuli resulted in reduced postprandial antral phasic pressure activity. The similarity of the responses to TENS applied to the hand and abdominal dermatomes suggests that the induced somatovisceral responses relay predominantly at the cerebral level.