Open AccessRegional differences in the number of neurons in the myenteric plexus of the guinea pig small intestine and colon: An evaluation of markers used to count neurons
Author(s) -
Karaosmanoglu Tufan,
Aygun Banu,
Wade Paul R.,
Gershon Michael D.
Publication year - 1996
Publication title -
the anatomical record
Language(s) - English
Resource type - Journals
eISSN - 1097-0185
pISSN - 0003-276X
DOI - 10.1002/(sici)1097-0185(199604)244:4<470::aid-ar5>3.0.co;2-z
Subject(s) - myenteric plexus , jejunum , ileum , neuron , biology , enteric nervous system , duodenum , descending colon , population , large intestine , guinea pig , anatomy , pathology , medicine , neuroscience , immunohistochemistry , endocrinology , immunology , rectum , biochemistry , environmental health
Background Subsets of myenteric neurons have been identified. To determine theproportional representation of neurons in each, it is necessary to relate the number of neurons inthe subset to that of the complete set. Prior estimates of total numbers of neurons, obtained withmany different markers, have varied widely. Methods Markers were compared for counting myenteric neurons in dissectedlaminar preparations of guinea pig duodenum, jejunum‐ileum, and colon; the effect of stretchingpreparations on these counts was also determined. Markers included the visualization ofsingle‐stranded nucleic acid with cuprolinic blue and the immunocytochemical demonstration ofneuron specific enolase (NSE), PGP9.5, S‐100, and the constitutive expression of a Fos relatedantigen (FRA). Results Neurons could not be counted accurately by demonstrating NSE, PGP9.5, orS‐100. The number of neurons detected by demonstrating FRA was consistently less than thatdetermined with cuprolinic blue (∼65%). Cuprolinic blue‐derived estimates of neuronnumbers were higher than most reported in the literature, but comparable to those recentlyobtained with “a nerve cell body” antiserum. Ganglionic area was found to be stretch independent.The rank order of neurons/cm 2 and ganglionic area/unit resting length was colon> duodenum ≫ jejunum‐ileum; more neurons were found in the myenteric plexus of thecolon (7.3 × 10 6 ) than in that of the entire small intestine (6.5 ×10 6 ). Conclusions Prior studies that have obtained denominators for estimating theproportions of myenteric neuronal subsets with markers that do not reveal the entire populationshould be re‐evaluated. The guinea pig colon contains a surprisingly large number of neurons, thephysiological significance of which must be determined. © 1996 Wiley‐Liss, Inc.