Colonic parasympathetic nerves

The colonic parasympathetic nerves are a critical component of the autonomic nervous system that regulates the motor, secretory, and vascular functions of the large intestine. This neural network is anatomically divided: the vagus nerve provides innervation to the proximal colon (ascending and transverse), while the pelvic splanchnic nerves, arising from the S2-S4 sacral spinal segments, supply the distal colon and rectum (StatPearls, 2023). These nerves primarily release acetylcholine, which binds to muscarinic receptors—specifically the M3 subtype—on colonic smooth muscle cells to stimulate peristaltic contractions and on epithelial cells to promote secretion (PubMed, PMC5447563). Impairment of this system is a hallmark of several gastrointestinal pathologies, including chronic idiopathic constipation, Hirschsprung disease, and neurogenic bowel dysfunction resulting from spinal cord injuries (NIH, 2022). While the nerves themselves are anatomical structures rather than single molecular targets, they are modulated by cholinergic drugs, acetylcholinesterase inhibitors, and bioelectronic therapies such as sacral nerve stimulation to manage motility disorders (Journal of Clinical Medicine, 2021).

Other names

Parasympathetic innervation of the colonPelvic splanchnic nervesVagal colonic innervationSacral parasympathetic outflow

Release of acetylcholine to activate muscarinic M3 receptors on colonic smooth muscle and enteric neurons, thereby increasing peristalsis and secretion.