Presynaptic ending

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Transmission of excitation from nerve cell  A with the presynapse to cell  B with the postsynapse  -
1 mitochondrion , 2  synaptic vesicles , 3  autoreceptors , 4  synaptic clefts with released unbound neurotransmitters , 5  postsynaptic receptors , 6  calcium channels , 7  exocytosis of the vesicle, 8  active transport through the cell membrane

Presynaptic terminal , and (synapse)  Endknöpfchen ( French bouton terminal ) or axon terminal , i.e. the end of a neurite and axon of a nerve cell (neuron), provided that the presynaptic part of a chemical synapse forms.

The most important function of a presynaptic region or presynapse is the signal-related release of neurotransmitters . These are stored here in synaptic vesicles and are released into the synaptic gap by exocytosis when action potentials arrive from the presynaptic nerve cell . The transmitters can then be bound to specific receptors on the membrane of the postsynaptic nerve cell and lead to cellular signals ( postsynapse ).

In the so-called en-passant synapses, the presynaptic part (as bouton en passant ) is not the end of the axon, but a thickening in its course, with all the components and functions of a presynapse.


  • Stefan Silbernagl, Agamemnon Despopoulos: Atlas of Physiology . 5., completely revised. and redesigned edition. Thieme (dtv), Munich 2001, ISBN 978-3-13-567705-7 .