A neurotransmitter is a chemical messenger released by a neuron that transmits signals to another cell, such as another neuron, a muscle cell, or a gland cell.
Neurotransmitters are released from nerve endings, usually into a small gap called a synaptic space, where they bind to receptors on a target cell. Depending on the neurotransmitter, receptor, and target cell, the resulting effect may stimulate or inhibit activity or modify how the cell responds to other signals.
Different neurotransmitters have different effects, and the same neurotransmitter can produce different effects depending on the receptor and the cells involved. Examples include dopamine, serotonin, acetylcholine, glutamate, and norepinephrine.
Neurotransmitters help regulate movement, sensation, mood, memory, sleep, and many automatic bodily functions.
QUICK FACT
Not all neurotransmitters simply “excite” or “calm” the brain. Their effects depend largely on the receptors they act on and the location where they act.
COMMONLY CONFUSED WITH
- Hormone: Neurotransmitters primarily transmit signals across connections between nerve cells or between nerves and their target cells, whereas hormones are generally released into the bloodstream to act on distant target tissues. Some chemicals, such as adrenaline and norepinephrine, can function in both roles.
- Receptor: a molecule or specialized structure that detects a chemical messenger or other signal and initiates a response.
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