Ultrastructural study of the mental body of Hydromantes genei (Amphibia: Plethodontidae).

Abstract

The mental glands of Hydromantes genei are considered a specialized form of the urodele serous cutaneous glands. Use of a variety of techniques of maceration and digestion as well as transmission electron microscopy (TEM) and scanning electron microscopy (SEM) has shown the three-dimensional morphology of secretory and myoepithelial cells. Secretory cells are pyramidal and rest on an almost continuous layer of myoepithelial cells. The latter have a long ribbon-like body from which branch off transversal and longitudinal processes with swallow-tailed ends. Cytoplasmic processes of secretory cells, containing irregular dense vesicles, squeeze through clefts between myoepithelial cells and may reach, at some points, the basal lamina. The interstices between myoepithelium and secretory cells are extraordinarily rich in nerve endings with clear vesicles. The glandular outlets appear as elliptical stomata in the superficial layer of the epidermis and are lined by horny cells, which invaginate to circumscribe the excretory duct. The morphological results indicate that the myoepithelium of Plethodontidae mental glands differ in some respects from that of amphibian serous cutaneous glands. A double polarity for the secretory cells is also suggested. © 1993 Wiley-Liss, Inc.