Neuromodulator refers to chemical that has properties intermediate between those of a neurotransmitter and those of a hormone.

A neuromodulator is a type of chemical messenger that is released by neurons to regulate the activity of other neurons. Unlike neurotransmitters, which act rapidly and locally at synapses, neuromodulators act more slowly and can have widespread effects on multiple brain regions.

Examples of neuromodulators include:

  1. Dopamine: Dopamine is a neuromodulator that plays an important role in the brain's reward and pleasure systems. It is also involved in movement, motivation, and learning.

  2. Serotonin: Serotonin is a neuromodulator that is involved in regulating mood, appetite, and sleep. It is also involved in the processing of sensory information and the control of movement.

  3. Acetylcholine: Acetylcholine is a neuromodulator that is involved in a wide range of functions, including muscle movement, attention, learning, and memory.

  4. Norepinephrine: Norepinephrine is a neuromodulator that is involved in the body's "fight or flight" response. It is also involved in attention, learning, and memory.

  5. GABA: Gamma-aminobutyric acid (GABA) is a neuromodulator that plays an important role in the regulation of anxiety and stress. It is also involved in the control of muscle tone and the modulation of pain.

Dysfunction of neuromodulators has been implicated in a variety of psychiatric and neurological disorders, including depression, anxiety, schizophrenia, Parkinson's disease, and Alzheimer's disease. Therefore, understanding the role of neuromodulators in the brain can be important for developing treatments and therapies for these conditions.