A system in the brain using the neurotransmitter acetylcholine that is based in the mesencephalic reticular activating system, and which distributes acetylcholine throughout the brain. This system has a widespread energising influence on brain activity, through both sympathetic and parasympathetic nervous systems, and is closely tied to sustained attention and alerting. Cholinergic receptors binding to acetylcholine are found in both systems. There are two types: nicotinic cholinergic receptors that induce sympathetic postganglionic neurons, adrenal chromatin cells, and parasympathetic postganglionic neurons to fire and release their chemicals, and muscarine receptors located in peripheral tissues (e.g., end plates of smooth muscle), and associated mainly with parasympathetic functions. In Alzheimer’s disease (AD), cholinergic neurons, established during the early migratory stages of embryonic development, are destroyed along with muscarinse receptors, according to the cholinergic hypothesis of AD.
See Acetylcholine (AcH), Alzheimer’s disease, Botulinus (or botulinum or botox), Entorhinal cortex, Hormones, Ligands, Limbic system, Mesencephalic reticular activating system, Motoneuron, Neurotransmitters, Parasympathetic nervous system (PNS), Sustained attention, Sympathetic nervous system (SNS)