This is quite technical but just posting for FYI to help some understand your post.
Although there are many neurotransmitters in the central nervous system, the peripheral nervous system has only two: acetylcholine and norepinephrine. Why are there so many brain neurotransmitters? Because the functions performed by brain neurotransmitters are not as uniform as they might superficially appear. Some (like glutamate) are excitatory, whereas others (like GABA) are primarily inhibitory.
Nicotinic acetylcholine receptors are present in many tissues in the body and are the best-studied of the ionotropic receptors. The neuronal receptors are found in the central nervous system and the peripheral nervous system.
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