Ultrastructure of Merkel cells in the epidermis of Hyla arborea

Abstract

In this ultrastructural study of the epidermis in Hyla arborea, cells quite similar to the Merkel cells already described in several vertebrate species are reported, and their relationships to the nerve terminals in intimate contact examined. Merkel cells occur rather frequently in the dorsal and ventral epidermis having features like these in other amphibian species: they contain specific, dense granules of various sizes throughout the cytoplasm, with focal accumulation near the plasma membrane areas apposed to nerve terminals. Occasionally seen are nerve endings with a peculiar fine structure suggestive of efferent nerve endings, for which a possible modulating function is proposed.