cells of Cajal (ICC) have been proposed as stretch receptors for vagal afferent nerves in the stomach based on immunohistochemical studies. The aim of the present study was to use electron microscopy and the anterograde degeneration technique to investigate ultrastructural features and survival dependency of ICC associated with vagal afferent innervation of the cat esophagus. This is the first report on the ultrastructural characteristics of ICC in the cat esophagus. Intramuscular ICC (ICC-IM) were identified throughout the musculature, whereas ICC in the myenteric plexus were rare. ICC-IM were particularly numerous in septa aligned with smooth muscle bundles. They were in synapse-like contact with nerve varicosities and in gap junction contact with smooth muscle cells. Smooth muscle cells also made contact with ICC through peg and socket junctions. Precision damage through small-volume injection of saline in the center of the nodose ganglion from the lateral side, known to selectively affect sensory nerves, was followed within 24 h by degeneration of a subset of nerve varicosities associated with ICC-IM, as well as degeneration of the associated ICC-IM. Smooth muscle cells were not affected. Nerves of Auerbachs plexus and associated ICC were not affected. In summary, ICC-IM aligning the esophageal muscle bundles form specialized synapse-like contacts with vagal afferent nerves as well as gap junction and peg-and-socket contacts with smooth muscle cells. This is consistent with a role of ICC-IM as stretch receptors associated with vagal afferent nerves; the ICC-vagal nerve interaction appears essential for the survival of the ICC. interstitial cells of Cajal; esophagus; stretch receptor; vagus; afferent innervation; intramuscular interstitial cells of Cajal FOR NORMAL ESOPHAGEAL function, the vagus nerves provide the major sensory and motor innervation to both striated and smooth muscle portions of the esophagus. Sensory pathways from the esophagus have been studied both electrophysiologically (40, 41) and by nerve tracing techniques (4,11,28). However, the precise location and structure of the sensory receptor(s) involved in control of esophageal motor function remain controversial. It is likely that more than one structurally and functionally distinct type of mechanoreceptor exists within the esophagus (4, 5, 8). As early as 1929, intraganglionic laminar nerve endings (IGLE) were considered candidates for esophageal stretch receptors (34). In an elegant study by Berthoud and Powley (4), intramuscular vagal afferents were shown to be positioned and structured as likely candidates for the gastric stretch receptor. Intramuscular arrays (IMA) enter circular or longitudinal muscle layers, run parallel to respective muscle fibers, and bifurcate to create an array of parallel terminal elements in stomach and sphincters (28). In the stomach, these terminal elements consist of interconnected parallel axonal telodendria that are arrayed in close proximity to one another and that form appositions with interstitial cells ...