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The groupHistamine was opened Nencki in 1876. It is a nutrient compound, formed in the body when decarbauxilirovania gistidina amino acids. Histamine can also producyrovtsa microorganisms inside the respiratory passages (Branchamella catarhalis, Haemophilus parainfluenzae, Pseudomonas aeruginosa). It is a component of some poisons and secrets that have irritating effects.
Under normal circumstances, histamine deposited GRANULATED fat cells and bazofilov tied, the down state. Various pathological condition (anaphylactic shock, burns, frostbite, pollinoz, urticaria and other allergic diseases), and the arrival of the body of certain chemical veschestv-liberatorov by gistamina release from the depot. Liberatorami gistamina include d-tubokurarin, morphine, iodized rentgencontrastnye preparations poligliukin and other high-molecular compounds. In allergic reactions from pre-sensitised fat cells histamine is with the application mediatorami (lakotriena and prostaglandins). Secretia gistamina arises from an interplay of C3a and C5a components complement to the specific membrannami receptor, or the antigen binding fixed on the cells IgE. Maximum gistamina concentration in the blood is recorded in five minutes after its release in the reactions гиперчувствительност и immediate type, and then it rapidly diffuses into surrounding tissue. Free of histamine causes smooth muscle (including muscle bronchi), the expansion of capillaries and hypotension. Accordingly act gistamina staz blood in the capillaries and an increase in permeability of the wall by the swelling of the surrounding tissue. In connection with the criminal reflectorian brain substance napochechnikov an adrenaline (narrowing arteriol and tachycardia). Histamine stimulates the secretion of gastric juice.
Only 2-3% gistamina excreted unchanged to the rest of it is metabolized involving diaminoxydasy to imidazoluksousna acid.
In 1950-55 respectively. Ash and Schild have a hypothesis that the fear gistamina at least two subtypes of receptors : N_1 and N_2. In recent years it has become evident that histamine is not only a mediator patofiziologicakih some states, but also functions as a neirotransmitter. In 1983 J.-M.Arrang et al. identified in the CNS new subtype receptors gistaminergicakih - N_3.
N_1-, N_2-, N_3-retseptora different konformaziei and tissue localization. Enlisting gistaminom N_1-retseptorov makes vazodilatatia, increased vascular permeability causes smooth muscle bronchi and intestines. The most characteristic of the institution N_2-retseptorov Increasing secreting glands stomach. N_2-retseptora involved in the regulation of heart muscle smooth muscle uterus, bowel receptacles. But N_1- receptors are involved in the development of allergic and immune reactions. The CNS all three types of receptors gistaminovykh : N_1- and N_2-retseptora are postsinapticakih discs, N_3- localized mainly presinapticeski. When stimulation N_3-retseptorov delayed release of the nerve endings of several mediators, including histamine, oppressed transfer to the institution of the sympathetic nervous system. Through them, mediated functions such as sleep / vigil, hormonal secretia, cardiovasculiarny control, etc. Research carried out in recent years, suggest that there will be a possibility of creating special funds operating in the N_3-retseptora, for the treatment of central nervous system diseases, including stimulants cognitive functions for the treatment of Alzheimer's disease and other age demenzi, illness, epilepsy.
There are two groups of drugs that have an effect on gistaminergicescuu transfer : gistaminomimetiki (directly stimulate receptors or increase the free endogenous gistamina) and gistaminolitiki. Recent interacting with receptors inhibit binding them gistamina or lower level gistamina free in the body. These drugs discussed below in the relevant chapters.