Neurotransmitters are endogenous chemical messengers that transmit signals between neurons, or from neurons to other cells. Neurotransmitters may transmit signals across neuromuscular junctions, between muscle cells, gland cells, and immune cells.
Over 100 substances that act as neurotransmitters to have been identified. The most common are:
- Amino acids:
- Cholinergic neurotransmitter: Acetylcholine (ACh)
- Trace amines: phenethylamine, N-methylphenethylamine, tyramine, 3-iodothyronamine, octopamine, tryptamine, etc.
- Unusual neurotransmitters:
- somatostatin, substance P, cocaine and amphetamine regulated transcript, opioid peptides
- Putative neurotransmitters:
- Others: anandamide, etc.: anandamide, etc.