Холинергическая модуляция секреции ацетилхолина в нервно-мышечном соединении

Abstract

The effect of cholinergic compounds (activators and blockers of nicotinic cholinergic receptors) on the acetylcholine secretion from motor nerve endings is of interest in connection with the questions of the feedback mechanism in the neuromuscular synapse. It is assumed that acetylcholine autoreceptors may exist on the nerve endings. Them activity changes be able affects the release of the transmitter in response to a nerve stimulus. However, numerous of experimental data do not give an unambiguous idea of the direction and mechanisms of action of both endogenous acetylcholine and other cholinergic compounds on the evoked transmitter quantal secretion at the neuromuscular synapse. The relevance of such studies is due to the need to decipher the effects of these compounds, since many of them are used in clinical practice. The review is devoted to the analysis of the results of studies carried out on objects classical for neurophysiology - neuromuscular preparations of warm-blooded animals using a radioisotope method for assessing the amount of a transmitter secreted from nerve endings and an electrophysiological method for determining the number of quanta released in response to a nervous stimulus. Numerous data obtained using activators and blockers of ionotropic nicotinic receptors, as well as the probable mechanisms of action of cholinergic compounds modulating the secretory process, are compared. A scheme for the regulation of quantum secretion was proposed, taking into account new information about the possible participation of the Schwann cell and about presynaptic homeostatic plasticity.