CALCIUM-ACTIVATED ADENOSINE TRIPHOSPHATASE AND GAP JUNCTIONS IN RAT EPIDERMIS
1988 年 21 巻 6 号 p. 521-533
詳細
1988 年 21 巻 6 号 p. 521-533
Ca++-activated adenosine triphosphatase (Ca++-ATPase) in the epidermal cells of rat skin was demonstrated with the method of Ando et al. (1981), and the presence of enzyme activity on the epidermal gap junctions was obtained. Furthermore, the gap junctions showing enzyme activity were examined morphometrically under a digigramer model-G (Muto Kogyo Co. Ltd., Japan).
The electron microscopic observation of epidermis showed reaction products of Ca++-ATPase on the entire cell surface continuously except desmosomes and basal cell membranes facing the basal laminae in the stratum Malpighii and a few reaction products in the stratum granulosum. With keratinocytes differentiating, activities seemed to be diminishing. The reaction products were also found on the cytoplasmic side of the gap junctional membranes. Gap junctions showing the reactions were more often detected in the upper portion of the stratum Malpighii and/or in the lower portion of stratum granulosum of the rat pad epidermis.
1. The findings of Ca++-ATPase in the rat epidermis might reflect changes in the intracellular level of calcium which occur during the proliferation and the differentiation of epidermal cells.
2. The unequal distribution of the epidermal gap junctions appears to be involved in the synchronous differentiation process and in the maintenance of the epidermal thickness.
