Presinaptice

Presinaptice is not a standard term in contemporary neuroscience. It may refer to presynaptic elements of chemical synapses—the neuronal component responsible for releasing neurotransmitters. In some cases, it is likely a misspelling of presynaptic. If encountered, the intended meaning typically aligns with the presynaptic side of the synapse.

Presynaptic terminals house synaptic vesicles containing neurotransmitters, the active zone for vesicle docking, and the release machinery. Action potentials open voltage-gated calcium channels, allowing Ca2+ influx that triggers fusion of vesicles with the plasma membrane via the SNARE complex (syntaxin, SNAP-25, synaptobrevin) and auxiliary proteins like synaptotagmin.

Vesicles are organized into pools: readily releasable, recycling, and reserve. After release, membranes are retrieved by endocytosis, refilled with transmitter, and recycled. Presynaptic modulation occurs through autoreceptors and neuromodulators that alter release probability and vesicle dynamics.

Presynaptic processes contribute to short-term plasticity, such as facilitation and depression, and to longer-term synaptic changes. Disruption of presynaptic function is linked to neurological conditions, and the presynaptic machinery is a target for drugs and toxins (for example, botulinum toxin inhibits acetylcholine release).

Presynaptic elements interact with postsynaptic receptors to convey signals. In modern literature, presynaptic describes the releasing side of the synapse, contrasting with postsynaptic structures that detect neurotransmitter.