postganglionaire

Postganglionaire (postganglionic) refers to neurons or nerve fibers of the autonomic nervous system that have their cell bodies in autonomic ganglia and project to target organs after synapsing with preganglionic neurons. Postganglionic neurons receive input from preganglionic neurons whose cell bodies reside in the spinal cord or brainstem and whose axons synapse on the ganglionic neuron.

In the sympathetic division, postganglionic neurons originate in the paravertebral sympathetic chain ganglia or in prevertebral (collateral) ganglia and extend to effectors such as smooth muscle, cardiac muscle, and glands. The majority release norepinephrine onto adrenergic receptors, producing sympathetic effects. A few postganglionic sympathetic fibers, notably those innervating sweat glands, use acetylcholine.

In the parasympathetic division, postganglionic neurons reside in terminal ganglia near or within their target organs. These postganglionic neurons are typically cholinergic, releasing acetylcholine to produce parasympathetic effects, and they have relatively short pathways from ganglion to target.

Anatomically, postganglionic neurons have their axons extending from the ganglion to effector tissues, where they influence smooth muscle contraction, glandular secretion, and other autonomic processes. Clinically, dysfunction of postganglionic neurons can contribute to autonomic neuropathies and disorders of reflex autonomic control.

See also: preganglionic neuron, autonomic nervous system, sympathetic nervous system, parasympathetic nervous system.