Effects of Hyperglycemia on Cortical Response to Esophageal Distension in Normal Subjects

Acute changes in the blood glucose concentrationaffect the intensity of gastrointestinal sensations. Theaim of this study was to examine the effects ofhyperglycemia on cortical potentials evoked byesophageal distension. In 16 healthy volunteers, a balloonwas positioned in the lower esophagus. A series of 50distensions was performed at both a lower volume(producing definite sensation) and a higher volume (producing unpleasant sensation), at bloodglucose concentrations of 5 and 13 mmol/liter. Triphasiccortical potentials were recorded from a midline scalpelectrode (Cz). During euglycemia, interpeak amplitudes were greater at the higher than the lowerballoon volume (P < 0.005). At the lower balloonvolume, the interpeak amplitudes were greater duringhyperglycemia than euglycemia (P < 0.05). There was no effect of the blood glucose concentration onamplitude at the higher balloon volume. We conclude thatin healthy subjects, the amplitude of the corticalresponse to moderate, but not unpleasant, esophageal distension is greater during hyperglycemia whencompared to euglycemia. These observations areconsistent with the concept of increased intensity ofgut sensation during hyperglycemia.