Developmental differences in neurohumoral modulation of the cat lower esophageal sphincter.

It is possible that age-related differences in gastroesophageal function during infancy may predispose the infant to abnormalities. We have therefore evaluated developmental differences in neurohumoral modulation of lower esophageal sphincter function in the cat. These studies were performed in an in vitro setting. In the adult cat, lower esophageal sphincter smooth muscle and postganglionic inhibitory neurons are more sensitive to muscarinic agonists than in the kitten. The circular smooth muscle of the adult lower esophageal sphincter is also more responsive to neurally mediated relaxation, brought about by electrical stimulation. However, there is no difference in response to exogenous vasoactive intestinal peptide between the two age groups. These data suggest that developmental differences in neurohumoral modulation of the lower esophageal sphincter occur in the cat.