This study was performed to investigate the morphometric and ultrastructural change in the adult and aged rat small intestine. The myenteric and submucous plexuses were stained by NADH-TR in the ileum of adult Sprague-Dawley rats (3 mo., 300~350 gm) and aged rats (24 mo., 500~550 gm). The neurons of myenteric and sumucous plexuses were divided into 3 groups depending on their cell body morphology. Type 1 cells were polygonal or round with abundant cytoplasm. Type 2 cells were spindle shaped and type 3 cells were small and round with scanty cytoplasm. The nerve cell numbers and sizes were measured using an image analyzer (VIDAS, Carl Zeiss, Co., Ltd.). Ultrastructural changes were observed by JEM-1200 EXII (JEOL Co., Ltd.) electron microscope. The result obtained are as followed: 1. In adult rats, majority of neuron population were type 3 and neuron density (total numbers/1 mm2) was more higher in submucous plexus than in the myenteric plexus. 2. Statistically significant loss of type 1 and type 2 neurons were in myenteric and submucous plexus of aged rat small intestine. 3. All types of neuron sizes were increased in aged myenteric and submucous plexuses. 4. Lipofusin granules were prominent in the cytoplasm of aged rat. Cell organelles were not shown degenerative change. These results suggest that type 1 and type 2 nerve cells which is originated from autonomic nerves were lost in aged rat small intestine. Ultrastructurally lipofusin granules were prominent in the cytoplasm of aged rat and the cell organelles were not degenerated.
Adult* ; Aging ; Animals ; Autonomic Pathways ; Cytoplasm ; Enteric Nervous System* ; Humans ; Ileum ; Intestine, Small* ; Myenteric Plexus ; Neurons ; Organelles ; Rats* ; Rats, Sprague-Dawley ; Submucous Plexus

BACKGROUND/AIMS: Digestion of dietary protein elevates intraluminal concentrations of glutamate in the small intestine, some of which gain access to the enteric nervous system (ENS). Glutamate, in the central nervous system (CNS), is an excitatory neurotransmitter. A dogma that glutamatergic neurophysiology in the ENS recapitulates CNS glutamatergic function persists. We reassessed the premise that glutamatergic signaling in the ENS recapitulates its neurotransmitter role in the CNS. METHODS: Pharmacological analysis of actions of receptor agonists and antagonists in concert with immunohistochemical localization of glutamate transporters and receptors was used. Analysis focused on intracellularly-recorded electrical and synaptic behavior of ENS neurons, on stimulation of mucosal secretion by secretomotor neurons in the submucosal plexus and on muscle contractile behavior mediated by musculomotor neurons in the myenteric plexus. RESULTS: Immunoreactivity for glutamate was expressed in ENS neurons. ENS neurons expressed immunoreactivity for the EAAC-1 glutamate transporter. Neither L-glutamate nor glutamatergic receptor agonists had excitatory actions on ENS neurons. Metabotropic glutamatergic receptor agonists did not directly stimulate neurogenic mucosal chloride secretion. Neither L-glutamate nor the metabotropic glutamatergic receptor agonist, aminocyclopentane-1,3-dicarboxylic acid (ACPD), changed the mean amplitude of spontaneously occurring contractions in circular or longitudinal strips of intestinal wall from either guinea pig or human small intestinal preparations. CONCLUSIONS: Early discoveries, for excitatory glutamatergic neurotransmission in the CNS, inspired enthusiasm that investigation in the ENS would yield discoveries recapitulating the CNS glutamatergic story. We found this not to be the case.
Amino Acid Transport System X-AG ; Animals ; Central Nervous System ; Dietary Proteins ; Digestion ; Enteric Nervous System* ; Glutamic Acid* ; Guinea Pigs ; Humans ; Intestine, Small ; Intestines ; Muscles ; Myenteric Plexus ; Neurons ; Neurophysiology ; Neurotransmitter Agents ; Proteolysis ; Receptors, Glutamate ; Submucous Plexus ; Synaptic Transmission

BACKGROUND/AIMS: Physical and/or emotional stresses are important factors in the exacerbation of symptoms in irritable bowel syndrome (IBS). Several lines of evidence support that a major impact of stress on the gastrointestinal tract occurs via the enteric nervous system. We aimed to evaluate histological changes in the submucosal plexus (SMP) and myenteric plexus (MP) of the distal ileum in concert with the intestinal motor function in a rat model of IBS with diarrhea. METHODS: The rat model was induced by heterotypic chronic and acute stress (CAS). The intestinal transit was measured by administering powdered carbon by gastric gavage. Double immunohistochemical fluorescence staining with whole-mount preparations of SMP and MP of enteric nervous system was used to assess changes in expression of choline acetyltransferase, vasoactive intestinal peptide, or nitric oxide synthase in relation to the pan neuronal marker, anti-Hu. RESULTS: The intestinal transit ratio increased significantly from control values of 50.8% to 60.6% in the CAS group. The numbers of enteric ganglia and neurons in the SMP were increased in the CAS group. The proportions of choline acetyltransferase- and vasoactive intestinal peptide-immunoreactive neurons in the SMP were increased (82.1 ± 4.3% vs. 76.0 ± 5.0%, P = 0.021; 40.5 ± 5.9% vs 28.9 ± 3.7%, P = 0.001), while nitric oxide synthase-immunoreactive neurons in the MP were decreased compared with controls (23.3 ± 4.5% vs 32.4 ± 4.5%, P = 0.002). CONCLUSIONS: These morphological changes in enteric neurons to CAS might contribute to the dysfunction in motility and secretion in IBS with diarrhea.
Animals ; Carbon ; Choline ; Choline O-Acetyltransferase ; Diarrhea* ; Enteric Nervous System ; Fluorescence ; Ganglia ; Gastrointestinal Motility ; Gastrointestinal Tract ; Ileum ; Intestine, Small* ; Irritable Bowel Syndrome* ; Models, Animal* ; Myenteric Plexus ; Neurons* ; Nitric Oxide ; Nitric Oxide Synthase ; Rats* ; Stress, Psychological ; Submucous Plexus ; Vasoactive Intestinal Peptide

Recently, it has been postulated that diabetic autonomic neuropathy is caused by reduction in availability of nerve growth factor (NGF) in enteric nervous system. This experiments were performed to determine the changes of the distribution of enteric neuropeptide by diabetes and these changes could be prevented by administration of NGF. Sprague Dawley rats (200~250gm) were made diabetic by a single intraperitoneal injection of streptozotocin 65 mg/kg in saline. Recombinant human NGF (Sigma, Co., Ltd.) were administered at a dose of 500ng/kg subcutaneously every day for consecutive 4 weeks after streptozotocin administration. After 4 weeks, rats were anesthetized with ether and perfused with 4% paraformaldehyde. ileum was dissected and prepared by whole mount preparation method. Prepared segments were immunostained for substance p, calcitonin gene-related peptide, vasoactive intestinal peptide, and galanin by PAP technique. For the observation of the interstitial cells of Cajal, segments were immersed in Champy-Maillet solution for 2 days Results obtained were as follows: 1. In myenteric plexus of diabetic rats, substance P-like and VIP-like immunoreactivity were not changed compared with that of the control group. CGRP-like and galanin-like immunoreactivity were decreased in diabetic group and immunoreactive cells for CGRP and galanin were also decreased 18.1% (P<0.01) and 43.7% (P<0.01) respectively. 2. In NGF administerd diabetic group, immunoreactivity of substance p, VIP, galanin in myenteric plexus were slightly increased and immunoreactive cells for substancre p, VIP, galanin were almost the same as that of the control group. However, immunoreactive cells for CGRP of myenteric plexus were not changed by NGF. 3. In submucous plexus of diabetic rats, immunoreactivity of all four neuropeptides(substance p, CGRP, VIP, galanin) were decreased compared with that of the control group. Immunoreactive cells for substance p, CGRP, VIP, and galanin were also decreased in 38.8%, 77.6%, 33.0%, and 35.7%, respectively (P<0.01). 4. In NGF administered diabetic group, immunoreactivities of substance p, VIP and galanin in submucous plexus were increased and the immunoreactive cells were increased significantly compared to diabetic group. However, immunoreactive cells for CGRP of submucous plexus were not changed by NGF. 5. Interstitial cells of Cajal of diabetic group were decreased 7.4% ovoidal cells (A type) and 28.3% round cells (B type) In NGF administered group, the morphology and the number of ICC were not different to the control group. With the above results, it could be assumed that NGF prevent the damage of neurotransmitter and ICC in enteric nervous system.
Animals ; Calcitonin Gene-Related Peptide ; Diabetic Neuropathies ; Enteric Nervous System ; Ether ; Galanin ; Humans ; Ileum ; Injections, Intraperitoneal ; Interstitial Cells of Cajal ; Myenteric Plexus ; Nerve Growth Factor* ; Neuropeptides ; Neurotransmitter Agents ; Peristalsis* ; Rats* ; Rats, Sprague-Dawley ; Streptozocin ; Submucous Plexus ; Substance P ; Vasoactive Intestinal Peptide

BACKGROUND: This study was done to obtain comprehensive data on changes in the structural components of the enteric nervous system in pediatric patients with intestinal pseudo-obstruction (IPO). We evaluated routinely processed, in formalin-fixed tissues by quantitative morphometric analysis. In addition, we used formalin-fixed tissue to explore the possibility of using previously proposed diagnostic criteria to evaluate frozen serial sections for intestinal neuronal dysplasia (IND) type B and hypoganglionosis. METHODS: We analyzed data for 19 IPO cases. Morphometric analysis for quantification of ganglia and ganglion cells (GCs) was done for the myentric and the submucous plexus. In addition, we determined the presence of immature GCs and the distribution of nerve fibers and interstitial cells of Cajal (ICC). RESULTS: Nine patients showed combined hypoganglionosis, IND, and decreased ICC; others showed various combinations of these. Several morphometric factors were significantly different between patient groups as well as being different than the control group. CONCLUSIONS: Our pediatric IPO cases showed extensive overlapping of pathological findings. And the findings suggest the utility of using previously proposed morphometrically measured factors in multiple frozen sections as diagnostic criteria for IND type B and hypoganglionosis in formalin-fixed tissue.
Enteric Nervous System ; Frozen Sections ; Ganglia ; Ganglion Cysts ; Humans ; Interstitial Cells of Cajal ; Intestinal Pseudo-Obstruction ; Nerve Fibers ; Neurons ; Submucous Plexus

Activity of the enteric nervous system (ENS) is controlled by the autonomic nerves under the normal physiological condition, even though ENS has been regarded to be independent from the central nervous system. However, the relation between myenteric neurons and vagus nerves has not been fully clarified. For the defining of topographical and functional relationship between these two nervous systems, we analyzed how many myenteric neurons are activated after electrical vagal stimulation in the rat. Bilateral cervical vagi were electrically stimulated (10 V, 5 msec, 40 Hz) for a duration of 30 minutes, and then each part of the small intestine was obtained. Fos, as a functional marker for neuronal activation, immunohistochemistry was used for the detection of vagally activated myenteric neurons. Total number of myenteric neurons was obtained using cuprolinic blue stained samples, and was calculated as 12,819+/-1,514, 14,261+/-1,452, 15,411+/-2,380 per unit area (1 cm2) in duodenum, jejunum and ileum, respectively. Fos-positive myenteric neurons were scarcely observed in the normal control group. After the electrical vagal stimulation, Fos-immunoreactive (IR) neurons were detected as 31+/-17%, 17+/-9%, 16+/-10% of total number of myenteric neurons in duodenum, jejunum and ileum, respectively. These data demonstrate that only some (16~31%) of myenteric neurons are regulated by vagal efferent input, and the duodenum receives much more vagal input functionally than other distal regions. Furthermore, these findings can be applied to trials defining the functional circuit of the myenteric nervous system linked to the vagus nerves, since Fos-positive nuclei can be easily double-labeled with various neurotransmitters existing in the myenteric neurons.
Animals ; Autonomic Pathways ; Central Nervous System ; Duodenum ; Enteric Nervous System ; Ileum ; Immunohistochemistry ; Intestine, Small* ; Jejunum ; Myenteric Plexus* ; Nervous System ; Neurons* ; Neurotransmitter Agents ; Rats* ; Vagus Nerve

Maturation of neurons of the myenteric plexus (MP) of human fetal sigmoid colon was studied at various weeks of gestation (WG). There is abundant literature on the development of MP in various segments of the gut but there are fewer reports on the development of MP in human sigmoid colon which is a site of various disorders. Sigmoid colonic segments from 12 aborted foetuses aged 14-23WG were processed for NADPH histochemistry. Stereologic evaluation of the neuronal cell profiles, numerical density, number of neurons per ganglion and myenteric fraction was conducted using using imageJ software. According to gestational age, foetuses were assigned into two groups (group 1 [n=7], less than <17WG and group 2 [n=5], more than >17WG). The overall size of neuronal cell profiles in the MP was significantly increased (P<0.05). The numerical density of neurons decreased in group 2 in comparison to group 1, the number of neurons per ganglion and myenteric fraction were increased in group 2 but all these were not statistically significant. This study revealed that the maturational event increases after 17WG and extensive innervations is established at 23WG. During prenatal life there is an increase in the neuronal cell size from 14-23WG signifying maturational process. Such studies are essential for clinicians and surgeons to correlate the normal and pathologic development of the enteric nervous system.
Cell Size ; Colon, Sigmoid ; Enteric Nervous System ; Ganglion Cysts ; Gestational Age ; Humans ; Myenteric Plexus* ; NADP ; Neurons ; Pregnancy

No abstract available.
Enteric Nervous System* ; Irritable Bowel Syndrome*

Interactions among the nervous, the endocrine and the immune systems enable the gut to respond to the dietary products, pathogens and microbiota, which maintains the homeostasis of the body. However, dysbiosis may induce or aggravate the gastrointestinal (GI) and extra-GI diseases through changing the activities of enteric nervous system (ENS), enteroendocrine cells and enteric immune cells. Here we review recent advances in the understandings on how intestinal flora may impact the enteric neuro-endocrine-immune system in the gut, thereby contributing to the regulation of pathophysiological processes.
Enteric Nervous System ; Gastrointestinal Diseases ; Gastrointestinal Microbiome ; Humans ; Immune System

BACKGROUND/AIMS: The role of the enteric (ENS) and central (CNS) nervous systems in the control of the retrograde giant contraction (RGC) associated with vomiting is unknown. METHODS: The effects of myotomy or mesenteric nerve transection (MNT) on apomorphine-induced emesis were investigated in 18 chronically instrumented dogs RESULTS: Neither surgery affected the RGC orad of the surgical site or the velocity of the RGC over the entire small intestine. Myotomy blocked the RGC for 17 ± 5 cm aborad of the myotomy, and the velocity of the RGC from 100 to 70 cm from the pylorus slowed (18.1 ± 3.0 to 9.0 ± 0.8 cm/sec) such that the RGC orad and aborad of the myotomy occurred simultaneously. After MNT, the RGC was unchanged up to 66 ± 6 cm from the pylorus, and the sequence of the RGC across the denervated intestine was unaltered. The velocity of the RGC from 100 to 70 cm from the pylorus increased from 12.8 ± 1.6 to 196 ± 116 cm/sec. After myotomy or MNT, the percent occurrence and magnitude of the RGC across the intestine 100 to 70 cm from the pylorus decreased. CONCLUSIONS: The CNS activates the RGC 10 to 20 cm aborad of its innervation of the intestine and controls the RGC sequence. On the other hand, the ENS plays a role in initiation and generation of the RGC.
Animals ; Central Nervous System ; Dogs ; Enteric Nervous System* ; Hand ; Intestine, Small ; Intestines ; Nervous System ; Pylorus ; Vomiting