Cholinergic Transmission

Acetylcholine (ACh) is a major neurotransmitter in the central and peripheral nervous systems. Cholinergic neurons in the central nervous system include the basal forebrain cholinergic group that projects to the cerebral cortex and has a major role in attention, sensory processing, and memory; the mesopontine group that projects to the thalamus, basal ganglia, and brainstem areas and is involved in arousal, reward, and control of muscle tone; and large aspiny neurons of the striatum controlling basal ganglia function. In the periphery, ACh is the neurotransmitter of motor neurons innervating skeletal muscle; preganglionic neurons innervating autonomic ganglia; and parasympathetic, enteric, and sudomotor sympathetic neurons. Acetylcholine acts via nicotinic receptors to elicit fast excitation and several subtypes of muscarinic receptors that exert a variety of modulatory actions. Given the widespread distribution and targets of ACh, cholinergic systems have a major role in a variety of neurologic disorders, including Alzheimer disease, neuromuscular transmission defects, and autonomic manifestation of autoimmune diseases, drugs, or toxins.