Neurotransmission

Neurotransmission (also known as synaptic transmission) refers to the process by which signaling molecules called neurotransmitters are released by a neuron (the presynaptic neuron), and bind to and activate the receptors of another neuron (the postsynaptic neuron). This process is essential for the propagation of signals across the synaptic cleft.

Mechanism of Neurotransmission

Neurotransmission begins when an action potential reaches the axon terminal of the presynaptic neuron. This triggers the opening of voltage-gated calcium channels, allowing calcium ions to enter the axon terminal. The influx of calcium ions causes synaptic vesicles filled with neurotransmitter molecules to fuse with the cell membrane, releasing the neurotransmitters into the synaptic cleft.

The neurotransmitters diffuse across the synaptic cleft and bind to specific receptors on the membrane of the postsynaptic neuron. This binding can either stimulate or inhibit the postsynaptic neuron, depending on the type of receptor and neurotransmitter.

Types of Neurotransmitters

There are many different types of neurotransmitters, each with their own specific roles. Some of the most well-known neurotransmitters include:

• Acetylcholine: Involved in muscle contraction and memory formation.
• Dopamine: Plays a role in reward and motivation.
• Serotonin: Regulates mood, appetite, and sleep.
• GABA: The main inhibitory neurotransmitter in the brain.
• Glutamate: The main excitatory neurotransmitter in the brain.

Disorders of Neurotransmission

Disruptions in neurotransmission can lead to a variety of neurological and psychiatric disorders. For example, Parkinson's disease is associated with a loss of dopamine-producing neurons, while depression is often linked to low levels of serotonin. Many drugs used to treat these conditions work by altering neurotransmission.

See Also

• Neuron
• Synapse
• Neurotransmitter
• Action potential

Neurotransmission

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  Synapse Schematic
• Ligand-gated Ion Channel
  Ligand-gated Ion Channel