Gastroesophageal reflux in the adolescent.

Gastroesophageal reflux (GER) is relatively common in adolescence. The severity of gastrointestinal symptoms associated with gastroesophageal reflux varies from an occasional burp to persistent emesis. Evaluation of most of these patients reveals no definable anatomic, metabolic, infectious, or neurologic etiology.

Protein kinase C mediates spontaneous tone in the cat lower esophageal sphincter.

The intracellular pathways responsible for maintenance of tone in the lower esophageal sphincter (LES) are not well understood. We show that the protein kinase C (PKC) antagonists (1-(5-isoquinolinesulphonyl)-2-methylpiperazine dihydrochloride) and calphostin C reduce spontaneous resting tone in LES muscle strips, whereas the calmodulin antagonist N-(6-aminohexyl-5-chloro-1-naphthalenesulfonamide hydrochloride) has no effect, which suggests that LES tone is maintained by a PKC-mediated mechanism. In addition, U73122, an inhibitor of phosphatidylinositol-4,5-bisphosphate (PIP2)-specific phospholipase C, and D609, an inhibitor of phosphatidylcholine-specific phospholipase C, reduced diacylglycerol formation and LES tone in a concentration-dependent manner.