Lack of direct effects of acyl ghrelin, des-acyl ghrelin, and obestatin on rat lower esophageal sphincter motility in vitro.

BACKGROUND Three ghrelin gene-derived peptides, acyl ghrelin, des-acyl ghrelin and obestatin, are implicated in the regulation of feeding, adipogenesis and glucose metabolism, as well as gut motility. The effects of ghrelin gene-derived peptides on lower esophageal sphincter motility, however, were unknown. METHODS We investigated the influence of acyl ghrelin, des-acyl ghrelin and obestatin on lower esophageal sphincter motility using the in vitro isolated muscle strip method. Both resting and carbachol-stimulated rat lower esophageal sphincters were tested. RESULTS Acyl ghrelin, des-acyl ghrelin and obestatin did not alter the resting tone of the lower esophageal sphincter, whereas carbachol increased the force of the muscle strips. Similarly, acyl ghrelin, des-acyl ghrelin and obestatin did not modify carbachol-induced stimulation of the lower esophageal sphincter, whereas papaverine significantly decreased the force of the muscle strips. CONCLUSION Since the contractile effects of carbachol and relaxant responses of papaverine on the lower esophageal sphincter were confirmed, our results demonstrate that acyl ghrelin, des-acyl ghrelin and obestatin have no direct effects on rat lower esophageal sphincter motility in vitro.