Synaptic vesicle

Synaptic vesicle‏‎

A synaptic vesicle is a small organelle found in neurons that stores various neurotransmitters. These vesicles are essential components of the synapse, the junction between two neurons, where they play a crucial role in the propagation of nerve impulses.

Structure

Synaptic vesicles are spherical structures with a diameter of about 40 nanometers. They are surrounded by a lipid bilayer and filled with neurotransmitters. The vesicle membrane contains various proteins that are involved in vesicle function, including SNARE proteins, which are essential for the fusion of the vesicle with the presynaptic membrane.

Function

The primary function of synaptic vesicles is to store and release neurotransmitters. When a nerve impulse reaches the synapse, it triggers the fusion of the vesicle with the presynaptic membrane, releasing the neurotransmitters into the synaptic cleft. The neurotransmitters then bind to receptors on the postsynaptic neuron, triggering a response in this neuron.

Recycling

After the release of neurotransmitters, the vesicle membrane is retrieved from the presynaptic membrane in a process called endocytosis. The vesicle is then refilled with neurotransmitters and prepared for another round of release. This recycling process is essential for the continuous function of the synapse.

Role in disease

Alterations in synaptic vesicle function can lead to various neurological disorders. For example, defects in vesicle recycling can lead to neurodegeneration, as seen in Alzheimer's disease and Parkinson's disease. Furthermore, some toxins and drugs can interfere with vesicle function, leading to neurotoxicity or altered neural communication.

See also

• Neuron
• Neurotransmitter
• Synapse
• Neurological disorder