SPATIAL RELATIONSHIPS OF ENTERIC NERVE-FIBERS TO VAGAL MOTOR TERMINALS AND THE SARCOLEMMA IN MOTOR END-PLATES OF THE RAT ESOPHAGUS - A CONFOCAL LASER-SCANNING AND ELECTRON-MICROSCOPIC STUDY

Enteric co-innervation of motor endplates in the rat esophagus was stu died with confocal laser scanning and electron microscopy, Enteric fib ers were demonstrated with immunocytochemistry for nitric oxide syntha se, vasoactive intestinal peptide or NADPH-diaphorase histochemistry. Vagal motor terminals were identified with calcitonin gene-related pep tide (CGRP) immunocytochemistry. Teloglia was stained with immunocytoc hemistry for S100, and TRITC-tagged alpha-bungarotoxin was used to del ineate endplate areas in immunofluorescence preparations, Both confoca l imaging and electron microscopy revealed intimate relationships betw een enteric and vagal terminals on the one hand, and enteric terminals and the sarcolemma on the other. In addition, electron microscopy cou ld point out direct apposition of a significant proportion of enteric varicosities to vagal motor terminals without intervening teloglial pr ocesses. These morphological data are compatible with pre- and postsyn aptic modulatory effects of enteric neurons on vagal neuromuscular tra nsmission in striated esophageal muscle.