Nitrergic innervation of the rat esophagus: focus on motor endplates

Nitric oxide synthase immunocytochemistry and correlated NADPH-diaphorase histochemistry were utilized to investigate nitrergic innervation of the rat esophagus. Almost all neuronal cell bodies and fibers around blood vessels, and in submucosa and mucosa which were immunoreactive for NOS, also co-stained for NADPH-diaphorase. A combined demonstration of motor endplates with tetramethylrhodamine alpha-bungarotoxin or calcitonin gene-related peptide immunocytochemistry demonstrated a nitrergic co-innervation of striated muscle fibers in all portions of the esophagus. The proportion of endplates co-stained increased from 35% to 78% from the cervical to the abdominal portion of the esophagus. These data indicate a role for NO in neuromuscular transmission in striated muscle of the esophagus.