Effect of L-NMMA on postprandial transient lower esophageal sphincter relaxations in healthy volunteers

In a previous study we showed that nitric oxide (NO) synthesis inhibition b y N-G-monomethyl-L-arginine (L-NMMA) reduced the number of transient lower esophageal sphincter relaxations:(TLESRs) triggered by gastric balloon dist ention. The role of NO in postprandial TLESRs and gastroesophageal reflux, however, is unknown. Therefore, we studied the effect of L-NMMA on meal-ind uced TLESRs and reflux episodes with simultaneous recording of esophageal p eristalsis, intraesophageal and intragastric pH, and gastric emptying in he althy volunteers. Ingestion of a solid meal resulted in an increase in TLES Rs [8.5 (6.3-11.0) 60 min] which was significantly inhibited by L-NMMA [6.0 (4.0-8.8) 60 min, P < 0.05]. In addition, the total number of reflux episo des was reduced. L-NMMA had no effect on intragastric meal distribution and gastric emptying, but attenuated the postprandial increase in intragastric pH. These results confirm the involvement of NO in the neurocircuitry unde rlying the triggering of TLESRs. The reduction in reflux by L-NMMA has to b e confirmed in patients with gastroesophageal reflux disease. NO may be inv olved in the regulation of gastric acid secretion.