EXACT CELLS (synonym: heparinocytes, labrocytes, mastocytes, fabric basophiles) — one of the main cellular forms of connecting fabric; are characterized by existence in cytoplasm of plentiful metachrome-tichesky granularity and ability to develop, store and emit biologically active agents (heparin, a histamine, etc.).
Since also their granules are for the first time described in 1877 by P. Ehrlich; in 1902 — 1906 A. A. Maximov in detail investigated Since at various animals. In a crust, time Since are revealed at many vertebrate animals, including at all mammals. Since are described in most bodies, however most often they are localized in friable fibrous connecting fabric about small vessels, under an epithelium and near glands of skin, mucous and serous membranes, in the capsule and trabeculas of parenchymatous bodies, in lymphoid bodies, peritoneal liquid.
The quantity, distribution and structure Since have specific, specific and age features. The sizes Since at the person vary from 3,5 to 14 microns, they are spindle-shaped or rounded shape (fig. 1). The cytoplasmic membrane (plasmolemma) forms folds and microvillis. Kernel usually roundish or oval. In cytoplasm (see) membrane and not membrane organellas are located. To membrane body of l of lamas belong a cytoplasmic reticulum (see. Endoplasmic reticulum), Golgi's complex (see Golgi a complex), mitochondrions and lysosomes; to not membrane — ribosomes, centrioles, macrotubules and microfilaments. The most part of cytoplasm is busy with granules, the quantity, the sizes, structure, chemical structure and tinktorialny properties to-rykh have specific features and depend on degree of their maturity and a functional condition of a cell. Diameter of granules varies from 0,3 to 2 microns. The basis them is made by a complex of heparin (see) and the main proteins, the histamine (see), and at a number of animals serotonin (see) and dopamine is attached to Krom (see Catecholamines). In Since with the participation of enzymes and r and l with at l of a f that z y, with at l of a f that d e in N silt silt - transferazg is synthesized heparin — sulphated glycose-minoglikan. Poorly sulphated heparin is localized in young cells and causes orthochomatic coloring of granules; strongly sulphated heparin is found in mature cells, it causes their meta chromatic coloring (see the Metachromasia). Granules can contain also other glikozaminoglikana — hondroi-tinsulfata (see. Chondroitinsulphuric acids), hyaluronic acids (see), and also glycoproteins (see). Except the main proteins, in Since proteolytic enzymes (chymase and tryptase), and also oxide elements (see), decarboxylases (see), phosphatases are presented (see) and others. Since can synthesize a histamine with the participation of enzyme of a gistidindekarbok-silaza, and also absorb it izv-
Fig. 1. Schematic изображение^ mast cells in friable not properly executed connecting fabric: 1 — a fibroblast; 2 — eosinophilic granulocytes; 3 — macrophages: 4 — mast cells.
not. Granules can have fibrillar, laminated, mesh and granular and crystalloid structure. In formation of granules Since, in particular protein synthesis, the cytoplasmic reticulum, and also Golgi's complex (see Golgi a complex) participates where glikozaminoglikana and their complexes with proteins are formed. In the beginning in the field of Golgi's complex appear small (about 70 nanometers), the dense pro-granules surrounded with a membrane, to-rye combine in a vacuole with the general membrane. Then the pro-granules located in a membrane merge, forming a loose structure. In the course of maturing of a granule there is a consolidation of its contents that defines polymorphism of structure of granules depending on degree of their maturity. Mature granules differ from unripe in the bigger electron density and homogeneity (fig. 2).
One of ways of secretion (allocation) of biologically active agents Since is degranulation (fig. 3), edges happens by the exocytosis which is a transitional form to apocrenic type of secretion (see Glands). Secretion can be also merokrinovy, i.e. substances can be emitted without degranulation, and less often golokrinovy, followed by destruction Since. The strengthened degranulation is an indicator raised
by Fig. 2. Diffraction pattern of a mast cell.
! — kernel; 2 — cytoplasm; 3 — unripe granules with grain structure; 4 — mature granules; 5 — shoots of a cytoplasmic membrane; x 2 5 Ltd companies.
Fig. 3. The diffraction pattern of a mast cell in the center of an aseptic inflammation: 1 —
a granule of n intercellular space; 2 — shoots of cytoplasm of a mast cell; 3 — granules in cytoplasm; X 50 Ltd companies.
functional activity Since it is observed at action of many physical, volumetric and biological factors. Usually degranulation is followed by process of recovery of granules.
The origin Since is not finalized. Assume that they develop from the limfotsitopodobny marrowy predecessor. Population Since is updated slowly. Since have low proliferative activity. In completely granulated Since mitoses (see the Mitosis) meet seldom, more often — in less granulated cells. Ability Since to proliferation is connected with their secretory activity. There is inverse relation between quantity Since also basophiles in blood: so, at rats, mice at high content Since basophiles in blood are absent, at Guinea pigs, rabbits, birds at small contents Since in blood a large number of basophiles is noted. Since differ from basophiles of blood in an origin, a structure and function. The quantity, structure and functional activity Since depend on age and the neurohormonal status of an organizkhm. Influence on Since hormones of a hypophysis (somatotropic, thyritropic and adrenocorticotropic), a thyroid gland (thyroxine), a pancreas (insulin), sex hormones (estrogen, progesterone, testosterone) is noted.
Functions Since are diverse. They participate in development of an inflammation, regulation of a blood coagulation, a lipometabolism, provide constancy of composition of connecting fabric, influencing a microcirculator-noye a bed (see Mikrotsirkulyation), education and permeability of the main substance, reproduction, migration and function of fibroblasts (see. Connecting fabric), macrophages (see), endotheliocytes (see the Endothelium), leukocytes (see), and also on immune responses.
A role of mast cells in an allergy. Since as well as basophiles, are the main target cells of allergic reaction. They are involved in allergic reaction by means of connection of the allergic antibodies (reagins) which are preferential belonging to IgE fixed on a cellular membrane (see Immunoglobulins), with allergen. It brings, according to I. S. Gushchin, B. Uvnes, A. R. JOhnson and Moeran (N. Pages of Moran), to activation Since also to release from them various biologically active agents, to-rye, affecting other cells and fabrics, cause external manifestations of reaction of immediate hypersensitivity, or himergichesky allergic reaction (see Mediators of allergic reactions). Thus, reaction Since is an obligatory and major link of the allergic reactions which are the cornerstone of an anaphylaxis (see), neinfek - tsionno - and l of l e rgichesky bronchial asthma (see), allergic rhinitises (see Rhinitis), conjunctivitis (see), a Quincke's edema (see Quincke swelled), a small tortoiseshell (see) and other manifestations of an atopy (see).
There are data that Since can take part also in reactions of hypersensitivity of the slowed-down type, thanks to ability antigenspetsifichesky T-limfotsi-tov at interaction with antigen to emit the lymphokines (see Mediators of cellular immunity) causing in turn activation Since also release from them of mediators and other biologically active agents.
Selective fixing of IgE-antibodies on Since is explained by presence at their cytoplasmic membrane of receptors, specific to IgE (apprx. 300 Ltd companies of receptors on one Since). Sites in the field of C84 domain of the molecule IgE are responsible for linkng of IgE with receptors. A receptor for IgE is the glycoprotein about a pier. it is powerful (weighing) about 50 000. Activation Since requires connection among themselves next, located on a membrane Since, molecules of IgE-antibodies a molecule of antigen, edges shall have for this purpose not less than two valencies. Monovalent antigens do not activate Since, but slow down the activation caused a multi-shaft by entny antigens. Binding by antigen bridges of IgE-antibodies leads to rapprochement of the last on a cellular membrane and, respectively, to rapprochement of membrane receptors of IgE-antibodies that is a push to activation Since. It is not excluded that activation Since is carried out by interaction of the sites of C83 domain opening in structurally changed molecule IgE-antibodies with the sites of a cellular membrane other than receptors for IgE.
According to the data obtained with the help fa call about - contrast Mick R osko and AI,
reaction sensibilized Since on antigen is morphologically shown in increase in their size, «boiling up» of a cell, a cut is followed by loss of cytoplasmatic granules as a result of degranulation of an iligranulolizis, loss of clearness of outlines of a cell that can be accepted for its destruction. Since at allergic reaction the fact that at degranulation from them ATP, a lactate dehydrogenase and the radioactive potassium (42K) which is previously entered into cells or chrome (51 Sg) as it occurs at obviously cyto ks iches to and x influences are not released demonstrates to lack of destruction x.
II and h and l N y y this and and the l of l of e r gi che with to about ii of reaction Since consists in activation of phosphodiesterase with the participation of the ions of Sa2+ coming to a cell from the extracellular environment or being in a cell and which are released from the connected state further there is an autocatalytic activation of esterase, apparently, due to destruction by this enzyme of the inhibiting protein. After activation there comes the volatile stage of reaction. Ions of Ca2f activate sokratitelny proteins that leads to rapprochement and merge of iyerigranulyarny and tsitoit zmati-chesky membranes, to movement of granules and their exit out of limits of a cell (exocytosis). At first spaces between granules and perngranulyarny membranes increase, then perigranulyarny membranes merge with each other and with the general cytoplasmic membrane. forming vacuoles. Zones of merge of membranes in these sites become thinner therefore sites of a hyperpermeability of a membrane are formed, or melt, creating visible means of communication (time), through to-rye a granule leave in extracellular space. Under the influence of low temperature. inhibitors of cellular respiration (see biological oxidation) and glycolysis (see), and also in the absence of ions of Sa2+, release of mediators is blocked. Recently the attempt of therapeutic use of c innar the izin (see) having selective effect on transmembrane transfer of ions of Sa2 + in mast cells is made.
Due to formation of visible messages and zones of a hyperpermeability of a cytoplasmic membrane the ions of Na which are contained in the extracellular environment + strenuously come to vacuoles and force out the biogenic amines (see Mediators of allergic reactions) connected by an ionic bond to proteins of a granular matrix.
Along with release from Since histamine, serotonin, eosinophilic chemotactic factor — ECF-A (English eosinophilic chemota-ctic factor of anaphylaxis), neytro-filyyugo a chemotactic factor — NCF (English neutrophil che-motactic factor) which are contained in granules Since in the preexisting (preeducated) form occurs activation of enzymes and such mediators as slowly reacting substance of an anaphylaxis SRS-A (English slow-reacting substance of anaphylaxis), the factor activating thrombocytes — PAP (English platelet activating' factor), and lipidic chemotactic factors are formed.
From the phospholipids of a cellular membrane activated Since release I are ah and<) about and about in and I to isl about pg and
(see). As a result of oxidizing and a roar of a rashcheniye and ra idonic to - you, to and t and l 11 z and r at e m () about i \and to l about about to with and e and and z about and (a cyclooxygenase way), are formed prostaglandins and thromboxanes (see Prostaglandiiy). Oxidizing transformation arachidonic to - you, catalyzed lipokspgenazy (whether-poksigenaznyi a way), bring to about ra zo in and a niya the guide ro ks ie ykozatet-rayenovy to - the t having humoral and cellular activity: they have hemotaksichesky effect on eoziiofila, strengthen with r about d with t in about to summer chn y x me m r and N and y x
receptors to SZ to a component of a complement (see), stimulate activity adenylate - and guanylate cyclases. Besides, as a result of oxidizing transformation arachidonic to - you on a lipoksigenazny way leukotrienes are formed. Believe that C4 (LTS4) leukotrienes, Dd (LTDL) and E4 (JITEj) represent SRS-A therefore inhibitors of a liioksigeiaza slow down release of SRS-A from mast cells and have thereby antiallergic effect.
Degranulation Since also release of mediators from them are under partial control of system of cyclic nucleotides: cyclic 3', 5 '-AMF (tsAMF) and cyclic 3', the 5th '-guanozinmono-phosphate (tsGMF). Increase in intracellular maintenance of tsAMF weakens, and increase in maintenance of tsGMF strengthens secretion of mediators. However in regulation of allergic reaction Since system adenylatecyclase — tsAMF has relative value. Adenylatecyclase Since can be stimulated E (PGE) prostaglandins, a histamine and in much smaller degree, than in other cells, stimulators of R-adrenergic receptors. Antiallergic effect of inhibitors of phosphodiesterase can be explained partially with braking of emission of mediators from Since due to increase in contents in cells of tsAMF.
D about for those l s TV about not c total ks iches which nature of degranulation Since proved the new principle of approach to control of allergic reactions consisting in stabilization of these cells and braking of their function. Antiallergic drug intal possesses stabilizing action on Since slows down release of mediators from them in response to allergen.
See also Allergy, the Inflammation.
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Sh e x t of e r A. B. Connecting fabric, page 62, M., 1981; X r at shch about and N. G. Functional cytochemistry of friable connecting fabric, M., 1969; Yur and -
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a-Methyl-5-Benzoxazole acetic acidj-a lipoxygenase inhibitor, Int. Arch. Allergy, v. 67, p. 340, 1982;
Fe r-n e x M. The mast-cell system, its relationship to atherosclerosis, fibrosis and eosinophils, Baltimore, 1968; G o e t z 1 E. J. Mediators of immediate hypersensitivity derived from arachidonic acid, New Engl. J. Med., v. 303, p.
822, 1980; Ishizaka T. Membrane events in triggering mast cells for IgE-mediated histamine release, in book: Advanc. allerg. clin. immunol., ed. by A. Oehling a. lake, p. 157, Oxford a. o., 1979;
The L ag li no f f D. a. Chi E. Y. Cell biology of mast cells and basophils, in book: Cell biology of inflammation, ed. by G.
Weiss-manii, p. 217, Amsterdam — N. Y., 1980; M a x i m about w A. A. Bindegewebe und blutbildende Gewebe, Handb. d. mikr. Anat. d. Menschen, hrsg. v. W. Mollen-dorff, Bd 2, T. 1, S. 232, B., 1927; R i-1 e at J. F. The mast cells, Edinburgh — L., 1959; Schauer A. Die Mastzelle, Stuttgart, 1964; S e d w i with k J. D., Holt P. G. a. Turner K. J. Production of a histamine-releasing lymphokine by antigen-or mitogen-stirnulated human peripheral T cells, Clin. exp. Immunol., v. 45, p. 409, 1981; Selye H.
The mast cells, Washington, 1965; V e 1 i-c a n C. a-Velican D. Histogenesis of mast cells, Folia histochem. cytochem., v. 1, p. 433, 1963; WassermanS. I. The lung mast cell, its physiology and potential relevance to defense of the lung, Environ. Hltii Perspect., v. 35, p. 153, 1980.
H. A. Yurina; I. S. Gushchin (ave.).