presináptica

Presináptica refers to structures or events that occur immediately before a synapse. A synapse is the junction between two nerve cells, consisting of a minute gap across which impulses pass by diffusion of a neurotransmitter. Therefore, a presynaptic neuron or presynaptic terminal is the neuron that transmits a nerve impulse across a synapse. It is the cell that sends the signal.

The presynaptic terminal typically contains synaptic vesicles, which are small sacs filled with neurotransmitters. When an action potential arrives at the presynaptic terminal, it triggers the release of these neurotransmitters into the synaptic cleft, the space between the presynaptic and postsynaptic neurons. These neurotransmitters then bind to receptors on the postsynaptic neuron, transmitting the signal.

The presynaptic membrane is the membrane of the presynaptic terminal that faces the synaptic cleft. It plays a crucial role in the release of neurotransmitters through a process called exocytosis. The efficiency and regulation of neurotransmitter release from the presynaptic terminal are vital for synaptic transmission and neuronal communication. Changes in presynaptic function can affect learning, memory, and overall brain activity. Understanding presynaptic mechanisms is therefore fundamental to neuroscience research.