Cytoskeletons, the complex set of protein fibers found in the cytoplasm, have important roles in the movement of cells and subcellular structures and the generation of shapes. Melanocytes have numerous dendritic processes which are in direct contact with many keratinocytes and transfer the melanosomes into the neighboring keratinocytes. Little information is available on the structure and function of cytoskeletons, and the effects of ultraviolet light on the cytoskeletons of the melanocytes.

The purpose of this study was to investigate the general cytoskeletal system of cultured melanocytes and to find out the effects of the cytoskeletal antagonists and UVB on the cytoskeletal system of the cultured melanocytes.

Melanocytes were cultured from adult foreskin and then exposed to various cytoskeletal antagonists and UVB radiation. The changes of the cultured melanocytes were evaluated by using phase contrast microscopy, immunofluorescence staining methods and electron microscopic examinations.

Colchicine produced shortening of dendrites, stellate cellular contour and granular fluorescence of the tubulin. Cytochalasin D produced round cellular contour and granular fluorescence of the actin. Acrylamide produced disorganization of cytoplasmic constituents, but no specific fluorescent change was observed. Colchicine also had inhibitory effects on the vimentin. Cellular responses induced by these agents were reversible. UVB caused morphological changes of the melanocytes, but their effects on the organization of the cytoskeletal system could not be detected in this method.

Microtubules are related to the dendritic movement of the melanocytes. Vimentin may be involved in the transfer of cellular organelles, probably including the melanosomes. Cytoskeletal antagonists produce their characteristic morphological changes to cultured melanocytes.