It has been demonstrated that @entity842 (NO) is a major inhibitory nonadrenergic, noncholinergic (NANC) neurotransmitter in the gastrointestinal (GI) tract. NO released in response to nerve stimulation of the myenteric plexus causes relaxation of the smooth muscle. NO is synthesized by the activation of neuronal NO synthase ( @entity2821 ) in the myenteric plexus. Released NO plays an important physiological role in various parts of the GI tract. NO regulates the muscle tone of the sphincter in the lower esophagus, pylorus, sphincter of Oddi, and anus. NO also regulates the accommodation reflex of the fundus and the peristaltic reflex of the intestine. Previous studies have shown that NOS inhibitors delay gastric emptying and colonic transit. The reduction of @entity2821 expression, associated with impaired local production of NO, may be responsible for @entity1319 in the GI tract. There is accumulated evidence that dysfunction of NO neurons in the myenteric plexus may cause various @entity344 . These reports are reviewed and possible mechanisms of altered @entity2821 expression are discussed in this article. In particular, impaired @entity2821 synthesis of the myenteric plexus seems to be an important contributing factor to the pathogenesis of @entity1318 , @entity6 , infantile @entity2202 , @entity1963 , and @entity1526 . Reduced NO release and/or @entity2821 expression are suspicious in a subset of @entity1 with functional @entity2210 . Although the etiology of @entity8442 remains unknown, it is conceivable that extrinsic denervation may upregulate @entity2821 expression, resulting in enhanced muscular relaxation and disturbed peristalsis. An animal model of @entity1960 showed impaired @entity2821 expression in the colonic myenteric plexus. @entity281 may be associated with the impaired NO pathways observed in functional @entity2210 , @entity1960 , and @entity1526 .

Pathophysiological significance of neuronal XXXX synthase in the gastrointestinal tract.

@entity1318 :: ('MESH:D004931', 'Disease') :: ['achalasia'] @entity2202 :: ('MESH:D046248', 'Disease') :: ['hypertrophic pyloric stenosis'] @entity1 :: ('9606', 'Species') :: ['patients'] @entity6 :: ('MESH:D003920', 'Disease') :: ['diabetic gastroparesis'] @entity8442 :: ('MESH:D007418', 'Disease') :: ['intestinal pseudo-obstruction'] @entity1963 :: ('MESH:D006627', 'Disease') :: ["Hirschsprung's disease"] @entity344 :: ('MESH:D005767', 'Disease') :: ['GI diseases'] @entity2821 :: ('4842', 'Gene') :: ['nNOS'] @entity1526 :: ('MESH:D014355', 'Disease') :: ["Chagas' disease"] @entity1960 :: ('MESH:D003092', 'Disease') :: ['colitis'] @entity281 :: ('MESH:D007239', 'Disease') :: ['Antecedent infection'] @entity842 :: ('MESH:D009569', 'Chemical') :: ['nitric oxide'] @entity2210 :: ('MESH:D004415', 'Disease') :: ['dyspepsia'] @entity1319 :: ('MESH:D015835', 'Disease') :: ['motility disorders']
@entity842 :: (MESH:D009569,Chemical) :: ['nitric oxide']
