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In the nervous system, a synapse [1] is a structure that allows a neuron (or nerve cell) to pass an electrical or chemical signal to another neuron or a target effector cell. Synapses can be classified as either chemical or electrical, depending on the mechanism of signal transmission between neurons.
The synapse is formed at a narrow gap between the pre- and postsynaptic neurons known as a gap junction. At gap junctions, such cells approach within about 3.8 nm of each other, [1] a much shorter distance than the 20- to 40-nanometer distance that separates cells at a chemical synapse. [2]
A diagram of the proteins found in the active zone. The active zone is present in all chemical synapses examined so far and is present in all animal species. The active zones examined so far have at least two features in common, they all have protein dense material that project from the membrane and tethers synaptic vesicles close to the membrane and they have long filamentous projections ...
The neuromuscular junction (NMJ) is the most well-characterized synapse in that it provides a simple and accessible structure that allows for easy manipulation and observation. The synapse itself is composed of three cells: the motor neuron , the myofiber , and the Schwann cell .
Mutants in rab-3 and munc-18 alter vesicle docking or vesicle organization at release sites, but they do not completely disrupt docking. [14] SNARE proteins, now also appear to be involved in the docking step of the cycle. [15] 4. Priming. After the synaptic vesicles initially dock, they must be primed before they can begin fusion.
Two molecular mechanisms for synaptic plasticity involve the NMDA and AMPA glutamate receptors. Opening of NMDA channels (which relates to the level of cellular depolarization) leads to a rise in post-synaptic Ca 2+ concentration and this has been linked to long-term potentiation, LTP (as well as to protein kinase activation); strong depolarization of the post-synaptic cell completely ...
(iii) If synapse arrives anywhere on the dendrite, but the dendrite is completely linear. In the last case, the cable acts as a linear filter; these linear filter properties can be included in the formulation of generalized integrate-and-fire models such as the spike response model. The filter properties can be calculated from a cable equation.
Tripartite synapse refers to the functional integration and physical proximity of: The presynaptic membrane, Postsynaptic membrane, and their intimate association with surrounding glia. It also refers as well as the combined contributions of these three synaptic components to the production of activity at the chemical synapse. [1]