[Ultrastructure of tissue basophils and capillaries during different periods of pre- and postnatal development of the dermis in the rat].

Dynamics of ultrastructure of mast cells (MC) and that of the capillaries of the derma have been studied by means of electron morphometry methods in rats during pre- and postnatal ontogenesis. The dynamics of the Golgi complex volume, that of the mitochondria and specific granules have been calculated in the total volume of the MC membrane organelles. Certain new data have been obtained on the process of the MC specific granules formation in the derma from progranules up to the stage of a mature granule. The process mentioned is most intensive during the first weeks of the postnatal ontogenesis. At the age of two weeks, signs of an active exocytosis of the granules are noted. Judging by certain morphological signs, development of transendothelial transport of substances in capillaries takes place in parallel with formation of the specific granules and corresponds to the beginning of exocytosis of substances in the MC granules. The correlative analysis proves that formation of the MC specific granules is connected with the number of microvesicles in cytoplasm of endotheliocytes.