HYPERGLYCEMIA-INDUCED ATTENUATION OF RECTAL PERCEPTION DEPENDS UPON PATTERN OF RECTAL BALLOON INFLATION

This study investigated the effects of acute hyperglycemia on consciou s rectal perception in response to two different rectal distension par adigms. Eleven healthy males were studied in random order on two separ ate days during euglycemia and hyperglycemia with blood glucose concen trations clamped to 3.8 +/- 0.6 and 14.8 +/- 0.86 mmol/liter, respecti vely. In order to evoke sensory responses, rapid phasic and ramplike d istensions were applied to an intrarectal balloon. Rectal sensation th resholds for initial sensation, sensation of stool and discomfort, and sensory intensities were recorded. Additionally, anorectal motor resp onses were investigated during phasic distension. Acute hyperglycemia did not modify rectal sensory pressure thresholds and perception score s in response to phasic distension. Neither did hyperglycemia alter th e resting anal sphincter pressure, the pressure threshold for elicitin g the rectoanal inhibitory reflex, or the maximal anal squeeze pressur e. In contrast, hyperglycemia attenuated rectal perception in response to ramplike distension. The pressure thresholds, 10.0 +/- 1.8 and 17. 0 +/- 3.6 mm Hg for initial sensation and discomfort, respectively, du ring hyperglycemia were significantly higher than the corresponding th resholds of 4.4 +/- 1.4 and 11.4 +/- 1.9 mm Hg observed during euglyce mia (P < 0.01). Higher rectal pressures were observed at all intensiti es of sensation of stool and discomfort during hyperglycemia than thos e obtained during euglycemia (P < 0.01). Hyperglycemia did not alter t he compliance of the rectum. The results of this study demonstrate tha t acute hyperglycemia attenuates rectal perception, and this attenuati on depends upon the type of distension employed. Our findings also dem onstrate that anal sphincter motor function is not appreciably modifie d by hyperglycemia.