EFFECTS OF GLYCERYL TRINITRATE ON THE PYLORIC MOTOR RESPONSE TO INTRADUODENAL TRIGLYCERIDE INFUSION IN HUMANS

The retardation of gastric emptying induced by infusion of triglycerid e into the small intestine is associated with suppression of antral pr essure waves and stimulation of basal pyloric tone in combination with phasic pressure waves localized to the pylorus. The role of nitric ox ide (NO) mechanisms in the control of pyloric motility was evaluated i n 12 healthy male subjects (21-43 years), using the NO donor glyceryl trinitrate (GTN). Antropyloric pressures were measured with a manometr ic assembly incorporating nine sideholes, spanning the antrum and prox imal duodenum, and a pyloric sleeve sensor. On separate days, an intra duodenal triglyceride infusion (10% intralipid at 1 mL min(-1)) was st arted during antral phase I activity and continued for 60 min. On one of the days GTN (600 mu g) was given sublingually 20 min after start o f the triglyceride infusion. The tonic pyloric motor response to trigl yceride [5 . 6 (SEM 0 . 8,) vs. 2 . 7 (1 . 3) mmHg, P < 0 . 001] and b oth the number [3 . 2 (0 . 2) vs. 2 . 2 (0 . 2) min(-1), P < 0 . 05] a nd amplitude [40 (4) vs. 27 (5) mmHg, P < 0 . 05] of phasic isolated p yloric pressure waves were reduced by GTN. These observations suggest that NO mechanisms are involved in the regulation of pyloric motor act ivity in humans.