GASTRIC NEUROLOGY - EVOLVING CONCEPTS AND TECHNIQUES

Gastric function is finely modulated by a series of neurological mecha nisms, so that gastric digestion is normally not perceived. Alteration of these control mechanisms may lead to different situations, which a re frequently associated with symptoms. An impaired tonic contraction of the proximal stomach, that is, an impaired gastric tone, results in gastroparesis. Patients with functional dyspepsia, and also patients with achalasia, have impaired meal accommodation of the stomach. Inter estingly, patients with functional dyspepsia may also have a sensory d ysfunction, and both dysfunctions could play a synergistic role. Howev er, the sensory dysfunction in dyspepsia, particularly the types of af ferent fibres affected, and the mechanisms of impaired accommodation, still remain to be characterized. Evaluation of gastric function has b een approached using the barostat. However, the barostat has limitatio ns and potential technical pitfalls that require proper attention. Mea l ingestion induces a variety of reflexes and the net result is a rela xation of the stomach. However, gastric reflexes can be best evaluated with the stomach empty, when the stimuli are applied at a different s ite. Nevertheless, altered reflex responses may be difficult to interp ret. For instance, absent or decreased relaxatory responses may equall y correspond to a gastroparetic stomach without tone or to a dyspeptic stomach unable to relax. In this context, it may be important to meas ure basal tone. Distension of the stomach by means of the barostat has been also used to test gastric sensitivity. However, recent studies h ave shown that perception of gastric distension relays on stimulation of tension receptors; since wall tension depends on both pressure and volume, distension with the barostat may be difficult to standardize. Hopefully, a battery of tests may become available in the near future for a complete neuromuscular evaluation of the gut. Eur J Gastroentero l Hepatol 10:733-735 (C) 1998 Lippincott Williams & Wilkins.