Extrinsic Innervation of Myenteric Plexus of Human Large Intestine Via Colonic Nerves

Colonic nerves were labelled by biotinamide ex vivo; filled axons were studied in myenteric ganglia of human colon. Multiplexed immunohistochemistry (up to 12 markers) distinguished sympathetic, parasympathetic, and extrinsic sensory endings, with evidence for selective targeting of enteric neurons.

The enteric nervous system plays a major role controlling gut motility, secretion, blood flow, and immune activity. Extrinsic neural pathways modulate the enteric nervous system; these have been investigated using biotinamide applied to human colonic nerves, ex vivo (n = 20; 13 female, 63 ± 18 years; mean ± standard deviation), followed by multilayer immunohistochemistry (Supplementary Table 1 for details of antisera).1 Biotinamide-filled axons entered the bowel wall and quickly joined the myenteric plexus, projecting for up to 20 mm before fading. In ganglia, extrinsic axons branched extensively, forming varicose endings (Figure 1). No intraganglionic laminar endings2 were observed. All preparations had biotinamide-filled viscerofugal neuron cell bodies