Nerve-myoepithelium and nerve-glandular epithelium contacts in the lacrimal gland of the sheep.

Abstract

Electron microscope studies of several types of secretory glands (6, 17, 18) have shown that myoepithelial cells envelop the acini and resemble smooth muscle cells in their fine structure (15). No close nerve-myoepithelium contacts with a separation of less than 0.1 /i have been described, and it has been suggested, for example in the rat submaxillary gland, that activation of the myoepithelium may occur by diffusion of transmitter substance over relatively long distances (18). In examining the fine structure of the lacrimal gland of sheep, we have observed that nerves are in close association with both the myoepithelium and the acinar epithelium. The material was taken from an animal under fluothane anesthesia, fixed with 1% Os0 in a phosphate buffer, pH 7.6 (10), and embedded in Araldite (8). Unsupported sections, about 1,000 A thick, cut with glass knives in a Cambridge-Huxley-pattern microtome, and double-stained with uranyl nitrate (Merrillees, unpublished observations) and with lead citrate (11), were examined in a Hitachi 1iB electron