Neurotransmitters are used all over the body. A lot is centralized in the brain, but the periphery also uses neurons and neurotransmitters. Neurotransmitters i

Neurotransmitters are used all over the body. A lot is centralized in the brain, but the periphery also uses neurons and neurotransmitters. Neurotransmitters in general don't particularly imply they're being used in the brain. Some neurotransmitters travel through the body, but a larger fraction are produced locally by a cell and intended only for close neighbors.