Human myenteric plexus: confirmation of unfamiliar structures in adults and neonates

To define the myenteric plexus along the human gastrointestinal tract, we studied three neonatal and six adult specimens, postmortem, by silver impregnation. There were no clear differences between the neonatal and the adult gastrointestinal tracts. In the body of the esophagus, the plexus was sparse, with few ganglia; 30%-40% of fascicular intersections were devoid of ganglia. In the lower 5 cm, the esophagus had thick bundles of nerve fibers ("shunt fascicles"), which crossed the gastroesophageal junction and radiated to the periphery of the stomach through several branches. The plexus in the stomach was uniform, with intermediate and intrafascicular ganglia. A thick nerve bundle encircled the pylorus and gave branches on either side to the antrum and the duodenum. Shunt fascicles in the stomach did not cross the pylorus but extended to the distal antrum. In the duodenum and proximal jejunum, the plexus was regular, but in the mid-small intestine, the longitudinal interganglionic fascicles were more prominent than the circumferential fascicles. Distally, this pattern was reversed; circumferential fascicles were more prominent and ganglia were dense in the terminal ileum. Thin, short shunt fascicles were scattered along the entire small intestine, becoming more abundant in the terminal ileum. Short, thick shunt fascicles traveled proximally from the ileocecal junction for about 25-30 cm. As in the stomach, shunt fascicles did not cross the ileocecal junction, but a thick nerve bundle encircled it. In the cecum and proximal colon, the plexus was sparse with large intermediate and intrafascicular ganglia. In the rectum and distal colon, the plexus was dense, with parafascicular and intrafascicular ganglia. Long ascending nerves extended from the distal rectum into the midcolon. In addition, there were short, thick nerve bundles in the rectum that traveled proximally.     

Comparative anatomy of the myenteric plexus of the distal colon in eight mammals

The behavior of the most distal part of the colon in a variety of species suggests that the innervation of this part may differ from that of more proximal parts. Silver impregnation was used to demonstrate the arrangement of the myenteric plexus of the distal colon in eight species (rat, guinea pig, rabbit, Australian possum, American opossum, cat, dog, and monkey). A distal zone, approximately 5%-20% of the total length of the colon above the anal verge in the nonrodents, was characterized by a plexus of very irregularly disposed intersecting nerve bundles of highly variable size with few and small ganglia; this zone was absent in the three rodent species. A next most distal zone, approximately 10%-65% of the total colonic length, contained a stellate plexus of large, regularly disposed ganglia interconnected by small nerve fiber bundles upon which were superimposed large dark-staining nerve bundles; these bundles began to be seen at the level of the irregular rectal plexus and ran cephalad, bypassing some ganglia but giving off branches to others. These, called shunt fascicles, contained many myelinated nerve fibers. Above this zone, the plexus was a stellate plexus throughout the remainder of the colon.     

Distribution of nitric oxide synthase-containing nerves in the aganglionic intestine of mutant rats: A histochemical study

We examined the distribution of nerves containing nitric oxide synthase in the intestine of congenitally aganglionic rats, using a reduced nicotinamide adenine dinucleotide phosphate diaphorase histochemical method for whole-mount and cryostat specimens. A constricted intestinal segment extends from the terminal ileum to the anus in this mutant. No nerve elements with the activity were found in the affected terminal ileum, cecum, and proximal colon. Although intrinsic ganglionic neurons were absent along the constricted intestine, nerve fibers with the activity were found in both the submucous and intermuscular layers distal to the proximal colon. These fibers increased in density towards the rectum, forming hypertrophic nerve bundles and unusual fiber networks. However, positive fibers were never seen within the circular and longitudinal musculature of the constricted lesion. Some of these hypertrophic nerve bundles were continuous with ectopic ganglia that were situated in the adventitial connective tissue around the lower rectum and in the submucosa near the anus. The hypertrophic nerve bundles seemed to have an extrinsic origin; some of them may have originated from ectopic ganglia. These results suggest that the defective distribution of nerves containing nitric oxide synthase may be involved in the pathogenesis of congenital colonic aganglionosis.     

Substance P-containing nerve fibers are numerous in human but not in feline intestinal mucosa

The regional and topographic distribution of substance P-containing nerve fibers in the human and feline intestinal wall was studied by immunocytochemistry and radioimmunoassay. The concentration of substance P was measured in the different layers of the duodenum, jejunum, ileum, and colon. In both humans and cat, substance P fibers were fairly numerous, and the substance P concentration was comparatively high in the smooth muscle layer, including the myenteric ganglia. In humans, but not in cat, substance P fibers were numerous, and the substance P concentration was also high in the mucosa. Substance P-containing nerve cell bodies were observed in the myenteric ganglia of both species. In the submucous ganglia, such nerve cell bodies were seen in the human intestine only, suggesting that they represent the origin of the numerous mucosal substance P fibers in this species. Previous studies have revealed a relative paucity of substance P fibers in the intestinal mucosa of several mammals, such as mouse, rat, and pig. The cat can now be added to those having few mucosal substance P fibers, whereas humans seem to be notably rich in such fibers, suggesting that substance P may play a role in the regulation of mucosal functions in the human intestine.     

Enteric nerves in diabetic rats: increase in vasoactive intestinal polypeptide but not substance P

The distribution of vasoactive intestinal polypeptide (VIP) and substance P-like immunoreactivities was studied by immunohistochemistry in the myenteric plexus and circular muscle layer of the ileum and proximal colon of rats 8 wk after induction of diabetes with streptozotocin. A consistent increase was observed in fluorescence intensity of VIP-like immunoreactivity in the nerve fibers, and intensely stained cell bodies were significantly more frequent in the myenteric plexus of the ileum (p less than 0.001) from diabetic animals. Some varicosities of VIP-like immunoreactive fibers in the myenteric plexus appeared to be enlarged. Vasoactive intestinal polypeptide-like immunoreactivity was increased and VIP-like immunoreactive nerves appeared thicker in the circular muscle layer of both diabetic ileum and proximal colon. The VIP levels were measured biochemically in tissue consisting of the smooth muscle layers and myenteric plexus. A significant increase in the VIP content per centimeter of intestine was found in both the ileum (p less than and proximal colon (p less than 0.01) from diabetic rats. In contrast, no apparent change in substance P innervation was observed immunohistochemically in the myenteric plexus and circular muscle layer of either diabetic ileum or proximal colon when compared with controls. The results are discussed in relation to the symptoms of autonomic neuropathy of the gut in diabetes.     

Localization of neurokinin B receptor in mouse gastrointestinal tract

AIM: To observe the location of neurokinin receptor (NK3r)in the mouse gastrointestinal tract.METHODS: The abdomen of 8 male Kunming mice wereopened under anaesthesia with sodium pentobarbital. Theexposed gut organs were cleaned and kept moisture andtemperature. Then the esophagus, jejulum, ileum, colon,etc were respectively cut and the segments from thestomach to the distal colon were opened along themesenteric border. A circular 4mm ～ 6mm enteric part(pieces of 1 cr2 were to be prepared) and mucosa andsubmucosa were removed, then the longitudinal musclelayer was pulled off from the circular muscle layer undermicrophotography. They were rinsed in 50nmol @ L-1potassium phosphate-buffered saline ( PBS ).Immunohistochemistry and immunoreactive fluorescencewere used in the staining procedure.RESULTS: There was not NK3r-Like(-Li) positive material onthe smooth muscle cells of the esophagus, stomach,intestines and other regions. The nerve cell bodies withimmunoreactivity for NK3r were mainly distributed in thesubmucousal nerve plexus or myenteric nerve plexus of thegastrointestinal tract except for the esophagus, stomachand rectum. The reaction product was located on thesurface of the nerve cell plasma. lt was observedoccasionally in the cell plasma endosomes, but was veryweakly stained. Among the NK3-Like positive neurons in theplexus, the morphological type in many neurons' appenaedlike Dogiel Ⅱ type cells. Some neuron cell bodies were big,having many profiles, Some were long ones or havinggrading structure. Cell bodiy diameter was about 10μm-46μmand 8μm-42μm in myenteric plexus and submucous plexus.CONCLUSION: This study not only described the distributionof neurokinin B receptor in the mouse gut, but alsoprovided a morphological basis for deducing the functionalidentity of the NK3r-LI immunoreactivity neurons,suggesting the possibility that these neurons were closelyrelated to gastrointestinal tract contraction and relaxingactivity.     

Substance P-containing nerves in the human small intestine. Distribution, ultrastructure, and characterization of the immunoreactive peptide

Light and electron microscopic immunocytochemical techniques were used to examine the distribution and ultrastructure of substance P-immunoreactive nerves in human jejunum and distal ileum. The organization of human enteric substance P-containing nerves closely resembled that in other species. Dense arrays of varicose immunofluorescent fibers occurred in myenteric and submucous ganglia (which contained immunoreactive nerve cell bodies) and in the mucosa. There were fibers in both muscle layers, in the muscularis mucosae, and around blood vessels. Fibers in the myenteric plexus contributed to both ascending and descending pathways. Substance P-immunoreactive axon profiles contained small round and large round vesicles and were apposed to nerve cell bodies, and nonimmunoreactive and immunoreactive axon profiles. Synapselike contacts were occasionally observed on nerve cell bodies and processes. The substance P-like material was characterized by high pressure liquid chromatography and radioimmunoassay and found to be indistinguishable from the authentic undecapeptide. These results suggest that enteric nerves containing substance P may play similar roles in humans as in other species.     

Region-dependent effects of diabetes and insulin-replacement on neuronal nitric oxide synthase-and heme oxygenase-immunoreactive submucous neurons

AIM To investigate the intestinal segment-specific effects of diabetes and insulin replacement on the density of different subpopulations of submucous neurons. METHODS Ten weeks after the onset of type 1 diabetes samples were taken from the duodenum, ileum and colon of streptozotocin-induce diabetic, insulin-treated diabetic and sex-and age-matched control rats. Whole-mount preparations of submucous plexus were prepared from the different gut segments for quantitative fluorescent immunohistochemistry. The following double-immunostainings were performed: neuronal nitric oxide synthase(n NOS) and Hu C/D, heme oxygenase(HO) 1 and peripherin, as well as HO2 and peripherin. The density of n NOS-, HO1-and HO2-immunoreactive(IR) neurons was determined as a percentage of the total number of submucous neurons. RESULTS The total number of submucous neurons and the proportion of n NOS-, HO1-and HO2-IR subpopulations were not affected in the duodenal ganglia of control, diabetic and insulin-treated rats. While the total neuronal number did not change in either the ileum or the colon, the density of nitrergic neurons exhibited a 2-and 3-fold increase in the diabetic ileum and colon, respectively, which was further enhanced after insulin replacement. The presence of HO1-and HO2-IR submucous neurons was robust in the colon of controls(38.4%-50.8%), whereas it was significantly lower in the small intestinal segments(0.0%-4.2%, P 0.0001). Under pathophysiological conditions the only alteration detected was an increase in the ileum and a decrease in the colon of the proportion of HO-IR neurons in insulin-treated diabetic animals. CONCLUSION Diabetes and immediate insulin replacement induce the most pronounced region-specific alterations of n NOS-, HO1-and HO2-IR submucous neuronal density in the distal parts of the gut.     

Shunt fascicles in the gastric myenteric plexus in five species

Thick nerve bundles, called shunt fascicles, lie in the myenteric plexus of the stomach in guinea pig, rabbit, cat, opossum, and cynomolgus monkey. They enter the stomach at the cardia, either as extensions of the esophageal myenteric plexus or of vagal branches to the caudal esophagus, and radiate toward the greater curvature. They bypass ganglia in the orad part of the stomach but give off branches to ganglia in more caudad parts. They are more abundant in the gastric fundus and body than in the antrum; they are infrequent along the greater curvature of the antrum. About 4% of the fibers they contain are myelinated. Arterioles and venules follow shunt fascicles and give rise to perifascicular capillary networks. Shunt fascicles are prominent in the cat, opossum, and monkey; they are short, thin, and sparse in the rabbit and guinea pig. They do not appear to be extensions of the direct vagal branches to the stomach but may be special nerve pathways from the esophagus to parts of the stomach.     

Peptide-containing neurons in different regions of the submucous plexus of human sigmoid colon.

Specimens of the sigmoid colon were obtained from male and female patients (n = 11) with carcinoma of the colon or rectum and studied immunohistochemically for vasoactive intestinal polypeptide-, somatostatin-, substance P-, neuropeptide Y-, calcitonin gene-related peptide-, met- and leu-enkephalin-, 5-hydroxytryptamine-, and dopamine beta-hydroxylase-containing nerves. In the subdivisions of the submucous plexus (namely, Schabadasch's, Meissner's, and the intermediate plexuses), substance P- and vasoactive intestinal polypeptide-immunoreactive nerve fibers were the most numerous, and equal densities of these nerves were found in all three layers. In contrast, few neuropeptide Y-, met-enkephalin-, leu-enkephalin-, calcitonin gene-related peptide-, somatostatin-, 5-hydroxytryptamine-, and dopamine beta-hydroxylase-immunoreactive nerves were found in these regions. The nerve cell bodies of the submucous plexus contained vasoactive intestinal polypeptide, substance P, leu-enkephalin, somatostatin, and 5-hydroxytryptamine but not neuropeptide Y, met-enkephalin, calcitonin gene-related peptide, and dopamine beta-hydroxylase. Vasoactive intestinal polypeptide-containing nerve cell bodies were found in all three subdivisions. Substance P-, leu-enkephalin-, and somatostatin-immunoreactive nerve cell bodies were found in Schabadasch's plexus and the intermediate region of the submucous plexus, but they were absent from Meissner's plexus; 5-hydroxytryptamine-containing nerve cell bodies were only observed in Schabadasch's plexus. The possible function of the neuropeptide-, dopamine beta-hydroxylase-, and 5-hydroxytryptamine-containing neurons in the different layers of the submucous plexus is discussed.     

Selective damage of intrinsic calcitonin gene-related peptide-like immunoreactive enteric nerve fibers in streptozotocin-induced diabetic rats

The distribution of calcitonin gene-related peptidelike immunoreactive (CGRP-LI) nerve fibers in the myenteric plexus of ileum and proximal colon of rats 8 wk after induction of diabetes with streptozotocin was studied using immunohistochemical techniques. A marked decrease in CGRP-LI nerve fibers mainly around the ganglion cells of the myenteric plexus of both ileum and proximal colon was observed in diabetic rats. The sparsely located immunoreactive nerve cell bodies in the control rats were absent in the diabetic preparations. There were, however, intensely stained CGRP-LI varicose nerve fibers that ran through the internodal strands and over the myenteric ganglia of the diabetic intestines. These findings indicate the presence of CGRP-LI nerve fibers of dual origin in the intestinal wall. The absence of positive cell bodies and diminished CGRP-LI nerve fibers around the ganglion cells in the diabetic tissues suggest that the state of diabetes selectively affects CGRP-LI nerve fibers of intrinsic rather than extrinsic origin. Furthermore, the absence of change in substance P-like immunoreactivity in the enteric system of rats with streptozotocin-induced diabetes of the same duration suggests that calcitonin gene-related peptide and substance P are contained in different populations of intrinsic nerve fibers in the gastrointestinal tract of the rat.     

Distribution and density of substance P receptors in the feline gastrointestinal tract using autoradiography.

Autoradiography was used to localize and quantify substance P receptors in the feline gastrointestinal tract. The specific binding of 125I-Bolton Hunter substance P was determined in the esophagus, lower esophageal sphincter, antrum, pylorus, duodenum, jejunum, ileum, ileocecal sphincter, and colon. Competitive binding studies indicated that substance P binding sites or NK-1 receptor sites were demonstrated. The concentration of NK-1 receptors was greatest in the distal half of the gastrointestinal tract, with the highest concentrations in the proximal colon. The circular muscle layer contained the greatest amount of substance P binding. The location and density of binding sites for substance P may be important in understanding the relative importance of both the pharmacological responses to this neuropeptide and the immunohistochemical evidence of the peptide at different sites in the intestine.     

Gastrointestinal tract distribution of Salmonella enteritidis in orally infected mice with a species-specific fluorescent quantitative polymerase chain reaction

AIM: To identify and understand the regular distribution pattern and primary penetration site for Salmonella enteritidis (S. enteritidis) in the gastrointestinal tract. METHODS: Based on the species-specific DNA sequence of S. enteritidis from GenBank, a species-specific real-time, fluorescence-based quantitative polymerase chain reaction (FQ-PCR) was developed for the detection of S. enteritidis. We used this assay to detect genomic DNA of S. enteritidis in the gastrointestinal tract, including duodenum, jejunum, ileum, cecum, colon, rectum, esophagus and stomach, from mice after oral infection. RESULTS: S. enteritidis was consistently detected in all segments of the gastrointestinal tract. The jejunum and ileum were positive at 8 h post inoculation, and the final organ to show a positive result was the stomach at 18 h post inoculation. The copy number of S. enteritidis DNA in each tissue reached a peak at 24-36 h post inoculation, with the jejunum, ileum and cecum containing high concentrations of S. enteritidis, whereas the duodenum, colon, rectum, stomach and esophagus had low concentrations. S. enteritidis began to decrease and vanished at 2 d post inoculation, but it was still present up to 5 d post inoculation in the jejunum, ileum and cecum, without causing apparent symptoms. By 5 d post inoculation, the cecum had significantly higher numbers of S. enteritidis than any of the other areas (P < 0.01), and this appeared to reflect its function as a repository for S. enteritidis. CONCLUSION: The results provided significant data for clarifying the pathogenic mechanism of S. enteritidis in the gastrointestinal tract, and showed that the jejunum, ileum and cecum are the primary sites of invasion in normal mice after oral infection. This study will help to further understanding of the mechanisms of action of S. enteritidis.     

Morphometric quantification of normal submucous plexus in the distal rectum of adult healthy volunteers

OBJECTIVE: Inadequate morphometric characterization of the normal adult submucous plexus has precluded the diagnosis of colonic dysganglionoses associated with constipation, such as intestinal neuronal dysplasia type B (IND B). The internal submucous plexus (Meissner plexus) was morphometrically quantified in adult healthy volunteers. DESIGN: Open, prospective morphometric study in balanced groups of female and male volunteers. PARTICIPANTS: Thirty-seven adult healthy male and female volunteers with normal bowel function and no history of gastrointestinal disease. METHODS: Four jumbo rectal biopsies (3-5 mm3) were taken 5 and 10 cm above the pectinate line. Two expert gastrointestinal pathologists assessed biopsy sections after specific nerve cell staining for lactic dehydrogenase, nitric oxide synthase and acetylcholinesterase, mainly for characteristics of ganglia and nerve cells in the submucous plexus. RESULTS: No healthy individual demonstrated over 20% of submucosal ganglia as giant ganglia or more than four giant ganglia per 30 sections (the morphometric criteria for IND B). Single submucosal nerve cells and ganglion numbers halved between 10 and 5 cm above the pectinate line, but there were no age or gender differences. The biological variability of nerve cell and ganglion density in the submucous plexus was large. CONCLUSIONS: Healthy adults show less than 20% of submucosal ganglia as giant ganglia and no more than four giant ganglia per 30 rectal biopsy sections. There is therefore no overlap with the histomorphological criteria of IND B. These data therefore support the specificity of the previously defined criteria for IND B in adults.     

Differential effect of streptozotocin-induced diabetes on the innervation of the ileum and distal colon

The effect of short-term and long-term streptozotocin-induced diabetes on the pattern of distribution and tissue content of adrenergic and peptidergic nerves in ileum and distal (descending) colon of the rat was examined using immunohistochemical, biochemical, and immunochemical techniques. The effect of short-term streptozotocin-induced diabetes on the level of noradrenaline compared with weight-restricted (starved) and untreated controls in the celiac (celiac-superior mesenteric ganglia complex) and inferior mesenteric ganglia, which supply the two regions of the intestine, was also compared. The pattern of change in the distribution of dopamine-beta-hydroxylase-, substance P-, calcitonin gene-related peptide-, and vasoactive intestinal polypeptide-like immunoreactive nerve fibres that was observed in the ileum from diabetic rats was not evident in the myenteric plexus of distal colon. In contrast to the ileum, there was no evidence of degenerative change in any of the nerve types investigated in the myenteric plexus of the distal colon. The level of vasoactive intestinal polypeptide in the diabetic rat ileum was significantly increased, whereas the level of noradrenaline was reduced; no such changes were observed in the distal colon. The tissue content of noradrenaline in the celiac ganglion, which projects to the ileum, was increased at 8-week diabetes compared with both weight-restricted and untreated controls, whereas the diabetic state had no effect on the levels of noradrenaline of the inferior mesenteric ganglion, which projects to the distal colon. It is concluded that there is a differential effect of streptozotocin-diabetes on different regions of the rat intestine. The adrenergic and peptidergic innervation of the distal colon were changed little compared with ileum. This may be explainable in terms of the different functional roles of these two regions of the intestine and/or by the difference in origin of the sympathetic nerves supplying the two regions of the intestine.     

Neurochemical features of endomorphin-2-containing neurons in the submucosal plexus of the rat colon

AIM:To investigate the distribution and neurochemical phenotype of endomorphin-2(EM-2)-containing neurons in the submucosal plexus of the rat colon.METHODS:The mid-colons between the right and left flexures were removed from rats,and transferred into Kreb's solution. For whole-mount preparations,the mucosal,outer longitudinal muscle and inner circularmuscle layers of the tissues were separated from the submucosal layer attached to the submucosal plexus. The whole-mount preparations from each rat mid-colon were mounted onto seven gelatin-coated glass slides,and processed for immunofluorescence histochemical double-staining of EM-2 with calcitonin gene-related peptide(CGRP),choline acetyltransferase(Ch AT),nitric oxide synthetase(NOS),neuron-specific enolase(NSE),substance P(SP) and vasoactive intestinal peptide(VIP). After staining,all the fluorescence-labeled sections were observed with a confocal laser scanning microscope. To estimate the extent of the co-localization of EM-2 with CGRP,Ch AT,NOS,NSE,SP and VIP,ganglia,which have a clear boundary and neuronal cell outline,were randomly selected from each specimen for this analysis. RESULTS:In the submucosal plexus of the mid-colon,many EM-2-immunoreactive(IR) and NSE-IR neuronal cell bodies were found in the submucosal plexus of the rat mid-colon. Approximately 6 ± 4.2 EM-2-IR neurons aggregated within each ganglion and a few EM-2-IR neurons were also found outside the ganglia. The EM-2-IR neurons were also immunopositive for Ch AT,SP,VIP or NOS. EM-2-IR nerve fibers coursed near Ch AT-IR neurons,and some of these fibers were even distributed around Ch AT-IR neuronal cell bodies. Some EM-2-IR neuronal cell bodies were surrounded by SP-IR nerve fibers,but many long processes connecting adjacent ganglia were negative for EM-2 immunostaining. Long VIP-IR processes with many branches coursed through the ganglia and surrounded the EM-2-IR neurons. The percentages of the EM-2-IR neurons that were also positive for Ch AT,SP,VIP or NOS were approximately 91% ± 2.6%,36% ± 2.4%,44% ± 2.5% and 44% ± 4.7%,respectively,but EM-2 did not co-localize with CGRP. CONCLUSION:EM-2-IR neurons are present in the submucosal plexus of the rat colon and express distinct neurochemical markers.     

Differential changes in intrinsic innervation and interstitial cells of Cajal in small bowel atresia in newborns

AIM: To investigate morphological changes of the enteric nervous system (ENS) and the interstitial cells of Cajal (ICCs) in small bowel atresia.METHODS: Resected small bowel specimens from affected patients (n = 7) were divided into three parts (proximal, atretic, distal). Standard histology and enzyme immunohistochemistry anti-S100, anti-protein gene product (PGP) 9.5, anti-neurofilament (NF), antic-kit-receptor (CD117) was carried out on conventional paraffin sections of the proximal and distal part. RESULTS: The neuronal and glial markers (PGP 9.5, NF, S-100) were expressed in hypertrophied ganglia and nerve fibres within the myenteric and submucosal plexuses. Furthermore, the submucous plexus contained typical giant ganglia. The innervation pattern of the proximal bowel resembled intestinal neuronal dysplasia. The density of myenteric ICCs was clearly reduced in the proximal bowel, whereas a moderate number of muscular ICCs were found. The anti-CD117 immunore- action revealed additional numerous mast cells. The distal bowel demonstrated normal morphology and density of the ENS, the ICCs and the mast cells.CONCLUSION: The proximal and distal bowel in small bowel atresia revealed clear changes in morphology and density of the ENS and ICCs.     

Endoscopic tonometric assessment of intestinal perfusion in a canine model

In an anesthetized canine model tonometric balloons were colonoscopically placed into the right colon, left colon, and rectum. A femoral arterial line was established for the measurement of blood pressure and arterial bicarbonate. Laparotomy was performed and additional balloons were placed, via enterotomies, into the duodenum, jejunum, and ileum. Baseline measurements of intramural pH were obtained, and then the origin of the superior mesenteric artery was occluded. Additional measurements in all areas were made for two 1-hour intervals. Results showed rapid and marked acidosis as demonstrated by significant (p less than 0.001) pH changes in the jejunum, ileum, and right colon. There were no significant changes in the pH in the duodenum, left colon, or rectum. Systemic arterial pH remained normal. These data demonstrate that tonometric balloons endoscopically placed into the right colon will reflect superior mesenteric artery occlusion at an early stage, and that similar information is likely to be gained by endoscopic placement of these balloons into the jejunum.     

Region-specific differences in the human myenteric plexus: an immunohistochemical study using donated elderly cadavers

Purpose and methods

To identify site-dependent and individual differences in neuronal nitric oxide synthase (nNOS)-positive nerves of the myenteric plexus, we examined full-thickness walls of the stomach, pylorus, duodenum, ileum, colon, and rectum in 7 male and 8 female cadavers (mean ages, 80 and 87 years, respectively).

Results

The areas occupied by nNOS-positive nerve fibers in the myenteric plexus were fragmentary and overlapped with areas occupied by vasoactive intestinal polypeptide-positive fibers. The nNOS-positive fiber-containing areas per 1-mm length of intermuscular space tended to be larger at more anal sites, with positive areas four times greater in the rectum than in the stomach. Interindividual differences in rectal areas were extremely large, ranging from 0.017 mm² in one 80-year-old man to 0.067 mm² in another 80-year-old man. Similarly, the numbers of nNOS-positive ganglion cell bodies per 1-mm length in the rectum ranged from 4 to 28. These areas and numbers were weakly correlated (r?=?0.62; p?=?0.02). Interindividual differences in the rectum appeared not to depend on either age or gender.

Conclusions

Anatomic studies using donated cadavers carried the advantage of obtaining any parts of intestine within an individual, in contrast to surgically removed specimens. We speculated excess control of evacuation with laxatives as one of causes of atrophy of the rectal myenteric plexus.     

Oligoneuronal Hypoganglionosis in Patients with Idiopathic Slow-Transit Constipation

PURPOSE: Several alterations of the enteric nervous system have been described as an underlying neuropathologic correlate in patients with idiopathic slow-transit constipation. To obtain comprehensive data on the structural components of the intramural nerve plexus, the colonic enteric nervous system was investigated in patients with slow-transit constipation and compared with controls by means of a quantitative morphometric analysis. METHODS: Resected specimens were obtained from ten patients with slow-transit constipation and ten controls (nonobstructive neoplasias) and processed for immunohistochemistry with the neuronal marker Protein Gene Product 9.5. The morphometric analysis was performed separately for the myenteric plexus and submucous plexus compartments and included the quantification of ganglia, neurons, glial cells, and nerve fibers. RESULTS: In patients with slow-transit constipation, the total ganglionic area and neuronal number per intestinal length as well as the mean neuron count per ganglion were significantly decreased within the myenteric plexus and external submucous plexus. The ratio of glial cells to neurons was significantly increased in myenteric ganglia but not in submucous ganglia. On statistical analysis, the histopathologic criteria (submucous giant ganglia and hypertrophic nerve fibers) of intestinal neuronal dysplasia previously described in patients with slow-transit constipation were not completely fulfilled. CONCLUSION: The colonic motor dysfunction in slow-transit constipation is associated with quantitative alterations of the enteric nervous system. The underlying defect is characterized morphologically by oligoneuronal hypoganglionosis. Because the neuropathologic alterations primarily affect the myenteric plexus and external submucous plexus, superficial submucous biopsies are not suitable to detect these innervational disorders.