Neuronal populations in the submucous plexus of the human colon.

The submucous plexus of the human distal colon was studied in order to determine whether or not it contains two or more ganglionated plexuses which can be separately identified. Nerve cells were visualised in sections through the wall of the distal colon, and in wholemount preparations of laminae from the submucous plexus by staining for NADH-diaphorase activity. The submucous plexus appeared to contain three identifiable plexuses: Henle's plexus was located adjacent to the circular muscle layer, Meissner's plexus was located adjacent to the muscularis mucosae and a third intermediate plexus was found which lay closer to the muscularis mucosae than to the circular muscle. In Henle's plexus, there were fewer smaller neurons than in the other plexuses: 15.1% had an area less than 180 microns 2, while in the intermediate plexus and in Meissner's plexus the equivalent figures were 43.1% and 43.2%, respectively. In Meissner's plexus, approximately half the ganglia were associated with single fibre tracts and half with two or more fibre tracts, but in the intermediate plexus and Henle's plexus, approximately three quarters of the ganglia were associated with single fibre tracts and the remaining quarter with multiple tracts.