From Big Medical Encyclopedia

PINOCYTIC (pinocytosis; Greek pino to drink + kytos a receptacle, here — a cell + osis) — process of active absorption a cell of liquids or colloidal solutions of various substances.

P.'s phenomenon is for the first time described by Lewis (W. Lewis, 1931) during the studying of macrophages and fibroblasts in culture of fabric. The item is close to process of capture by cells of firm corpuscular particles — to phagocytosis (see). By means of P. penetration into a cell of substances with high a pier is carried out. it is powerful (weight).

Fig. 1. Diagrammatic representation of the main stages of process of a pinocytic: 1 — 2 — sedimentation (adsorption) of molecules of substance (dark circles) on surfaces of a cellular membrane, «hairs» — the hypothetical structures intended for deduction of the adsorbed molecules of substance, 3 — emboly of a cellular membrane with the adsorbed substance in a cell, 4 — 5 — education and an otshnurovyvaniye of a pinotsitozny bubble, in — disappearance of a wall of a pinotsitozny bubble and the subsequent intracellular digestion of the absorbed substance.

The initial stage of P. is reversible adsorption (sedimentation) of molecules of the absorbed substance on a surface of a cellular membrane. Then the irreversible phase of adsorption during which the cellular membrane vpyachivatsya in a cell follows and takes the adsorbed substance. Formed after this bubbles and tubules can otshnurovyvatsya from a cellular membrane and be located under it freely (fig. 1). A part of bubbles merges with lysosomes (see), and their contents are exposed to intracellular digestion. The item is not spontaneous and continuous process, it depends on presence in the environment of substances inductors which can be solutions of various salts, amino acids and proteins and especially gamma-globulin and gelatin. Processes of formation of pinotsitozny vacuoles, their otshnurovyvaniye and movement in a cell demand energy consumptions; they are stimulated with ATP and inhibited by the factors suppressing a metabolism.

Fig. 2. Process of transfer of substance through a membrane of an epithelium of intestines of a mouse by a pinocytic (diffraction pattern): at the basis of a brush border of an epithelium pinotsitozny bubbles (1) which are involved in a cell are formed, otshnurovyvatsya from a surface of a cellular membrane together with the contents and freely are located under it (2); X 6500.

The item is eurysynusic at the elementary organisms (e.g., amoebas). The item svoystven also to cells of various fabrics of metazoans and the person, especially to the cells bearing function of absorption, napr, to phages, cells of an epithelium of intestines (fig. 2), renal tubules, an endothelium of blood vessels. Pinotsitozny bubbles are found also in schwannian cells, reticular macrophages etc. See also Cell .

Bibliography: Post of X. Physiology of a cell, the lane with English, page 750, M., 1975; P about e r t and with E., Novinsky V. and With and e with F. Cytobiology, the lane with English, page 98, etc., M., 1973; The P e of N of c about in Yu. S. General cytology, M., 1978; Andre-sen of Page G. Nilsson J. R. Electron micrographs of pinocytosis channels in Amoeba proteus, Exp. Cell Res., v. 19, p. 631, 1960; Lewis W. H. Pinozytosis, Bull. Johus Hopk. Hosp., v. 49, p. 17, 1931.

T. A. Zaletayeva.