Physiology of synaptic transmission in a chemical synapse

Pot n tial action came on the presynaptic fiber to the synapse, Ring s Vaeth membrane depolarization, which comprises a calcium pump, and calcium ions are transferred into the synapse. Once in the cytoplasm of synaptic the Finishing and Nia, calcium binds to proteins of synaptic membrane vesicles (n y bubbles which are stored in which mediators), which leads to the release of copper and tori into the synaptic cleft, which membrane separates one neuron from another membrane. So stimulation (electrical action potential) of the neuron in the synapse is converted from an electrical pulse into a pulse x and ically, that is, each excitation of a neuron is accompanied by a release at the end of its axon of a portion of a biologically active substance — the mediate of pa. Next, the mediator molecules are associated with special protein molecules that are located on the membrane of another neuron. These Molek in ly called receptors . Receptors are uniquely designed and bind only one type of molecule (which is suitable as a “key to the lock”). Recipe of ra – protein structures that are integral proteins pla of mathic membrane. They are synthesized in the endoplasmic reticulum ribosomes of the first cell reticulum, then embedded in the membrane. Functional synapse activity depends on the number of receptors and their srods t va to the mediator (ligand). Artificially created ligands with high specific (m.   e.   acting only on a specific type or subtype of the receptor), affinity for receptors, can cause the same functional cell response as native mediators. The receptor with about costs from two parts. One can be called the “recognition center”, the other – the “ion channel”. If the mediator molecules occupied certain places (recognition center) on the receptor molecule, then the ion channel opens and the ions begin to enter the cell (sodium ions) or exit (potassium ions) from the cell. In other words, through the membrane ionic current flows, the cat about ing causes a change in potential across the membrane. This potential is called the postsynaptic potential . Depending on the nature of the t Indoor ion channels arise excitatory (channels for sodium and potassium ions open) postsynaptsynaptichesky potential (VPSP) or brake (channels for chlorine ions open) postsynaptic potential (TPSP). On the membrane of a neuron can simultaneously tries to ditsya two types of synapses: excitatory and inhibitory. Everything is determined by the device of the ion channel of the membrane. The excitatory membrane sina p ows both sodium and potassium ions. In this case, the membrane of the neuron is depolarized. The membrane of the inhibitory synapses only passes chlorine ions and is hyperpolarized. Obviously, if the neuron is inhibited, the membrane potential increases (hyperpolarization). Thus, due to the effect neuron through respective synapses can in h wake up or stop arousal, slow down. All these events, etc. to come in the soma and dendrites of many processes of the neuron (on after e them are up to several thousands of excitatory and inhibitory synapses).

After each pulse of special mediators destroyed and diffract ion or enzymes is their reuptake in PRESYNC n matic end. In synapses, there is a feedback phenomenon that is widespread in physiology: a mediator from the synaptic cleft can interact with receptors on the presynaptic membrane and not (and in the case of receptors ), which leads to the cessation of the release of the mediator. Akti in synapse strength may be modulated by modulating the action of neuro e diatorov receptors which are located on the axon or dendrite and minute and body synapse. If the synapse is passed through a lot of momentum, then p e receptors may reduce its sensitivity to neurotransmitter (this property provides adaptation receptors on neuronal processes s prefecture level). It is important to remember that there is no unambiguous relationship between the chemical nature of a synapse and the sign of its synaptic action (excitatory or inhibitory): one and the same mediator can have both a inhibitory and excitatory effect. Star synaptic action determined by the properties of the postsynaptic membrane, ie. E. Compound p e receptors that can respond in various ways to control the conductivity mediator and various ion channels.

local_offerevent_note April 11, 2019

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