Neurons secrete a variety of chemicals called neurotransmitters to communicate with other neurons, muscle cells, or glands.
Here's a breakdown based on the provided reference:
The type of neurotransmitter secreted depends on the specific neuron and its function. One well-known example is acetylcholine, which motor neurons in vertebrates secrete at the neuromuscular junction. This process involves the following steps:
- When an action potential (electrical signal) reaches the axon terminal (end of the neuron), voltage-dependent calcium channels open.
- Calcium ions (Ca2+) rush into the axon terminal.
- This influx of calcium triggers the release of acetylcholine into the synaptic cleft (the gap between the neuron and the target cell).
- Acetylcholine then binds to receptors on the target cell (e.g., a muscle cell), initiating a response, such as muscle contraction.
Other examples of neurotransmitters include:
- Glutamate: The main excitatory neurotransmitter in the brain.
- GABA (gamma-aminobutyric acid): The main inhibitory neurotransmitter in the brain.
- Dopamine: Involved in reward, motivation, and motor control.
- Serotonin: Involved in mood, sleep, and appetite.
- Norepinephrine (noradrenaline): Involved in alertness, arousal, and the fight-or-flight response.
Different neurons use different combinations of neurotransmitters, allowing for a wide range of signaling and communication within the nervous system.
