Description drugs: Acetylcholine (Acetylcholinum)
Acetylcholine refers to biogenic amines - substances produced in the body. For use as a drug for the pharmacological isslelovany compound is synthetically prepared in the form of chloride or other salt.
Acetylcholine is a quaternary monoammonium compound. It is chemically unstable substance that is in the body, with the participation of a specific enzyme cholinesterase (acetylcholinesterase) easily destroyed with the formation of choline and acetic acid.
Obrazuschiysya in the body (endogenous) acetylcholine plays a major role in the processes of life: he takes part in the transmission of nerve excitation in the central nervous system, autonomic nodes, the endings of the parasympathetic and motor nerves.
Acetylcholine is a chemical transmitter (mediator) nervous excitement; end of nerve fibers, for which it serves as a mediator, called cholinergic, and receptors that interact with them, called cholinergic receptors. Cholinergic receptors (as of Contemporary FOREIGN tepminologii - "holinotseptop") is a complex protein macromolecule (nucleoprotein), localized on the outer side of the postsynaptic membrane. Thus acetylcholine receptor postganglionic cholinergic nerves (heart, smooth muscle, glands) is designated as M-cholinergic receptors (muskarinochuvstvitelnye) and located in ganglionic synapses and neuromuscular synapses in somatic - (V. Anichkov C.) As n-cholinergic (nikotinochuvstvitelnnye). This division is due to the peculiarities of the reactions caused by interaction of acetylcholine with these biochemical systems: muskarinopodobnyh in the first case and nikotinopodobnyh - in the second (see Anticholinergic agents.); m- and n-cholinergic receptors are also found in various regions of the CNS.
According to current data, muskarinochuvstvitelnye receptors are divided into M1, M2 and M3 receptors, which are differently distributed in organs and heterogeneous in physiological value (see. Atropine, Pirentsepin).
Acetylcholine does not have a strict selective action on the nicotinic acetylcholine receptor species. In one degree or another, he acts on the M- and N-cholinergic receptors, and in the subgroup of m-cholinergic receptors.
Peripheral muskarinopodobnoe action of acetylcholine appears to slow the heart rate, the expansion of peripheral blood vessels and lowering blood pressure, strengthening the peristalsis of the stomach and intestine, reducing the muscles of the bronchi, uterus, pancreas and bladder, increased secretion of digestive, bronchial, sweat and lacrimal glands, contraction of the pupil ( miosis). Miotic effect is associated with increased contraction of the circular muscles of the iris, which is innervated by postganglionic cholinergic fibers of the oculomotor nerve (n. Oculomotorius).