The way you move.

Glial cells in the gut are specialized to fine-tune intestinal function.

Evidence of a Myenteric Plexus Barrier and Its Macrophage-Dependent Degradation During Murine Colitis: Implications in Enteric Neuroinflammation.

BACKGROUND & AIMS: Neuroinflammation in the gut is associated with many gastrointestinal (GI) diseases, including inflammatory bowel disease. In the brain, neuroinflammatory conditions are associated with blood-brain barrier (BBB) disruption and subsequent neuronal injury. We sought to determine whether the enteric nervous system is similarly protected by a physical barrier and whether that barrier is disrupted in colitis. METHODS: Confocal and electron microscopy were used to characterize myenteric plexus structure, and FITC-dextran assays were used to assess for presence of a barrier. Colitis was induced with dextran sulfate sodium, with co-administration of liposome-encapsulated clodronate to deplete macrophages. RESULTS: We identified a blood-myenteric barrier (BMB) consisting of extracellular matrix proteins (agrin and collagen-4) and glial end-feet, reminiscent of the BBB, surrounded by a collagen-rich periganglionic space. The BMB is impermeable to the passive movement of 4 kDa FITC-dextran particles. A population of macrophages is present within enteric ganglia (intraganglionic macrophages [IGMs]) and exhibits a distinct morphology from muscularis macrophages, with extensive cytoplasmic vacuolization and mitochondrial swelling but without signs of apoptosis. IGMs can penetrate the BMB in physiological conditions and establish direct contact with neurons and glia. Dextran sulfate sodium-induced colitis leads to BMB disruption, loss of its barrier integrity, and increased numbers of IGMs in a macrophage-dependent process. CONCLUSIONS: In intestinal inflammation, macrophage-mediated degradation of the BMB disrupts its physiological barrier function, eliminates the separation of the intra- and extra-ganglionic compartments, and allows inflammatory stimuli to access the myenteric plexus. This suggests a potential mechanism for the onset of neuroinflammation in colitis and other GI pathologies with acquired enteric neuronal dysfunction.

Method for Detecting Hyaluronan in Isolated Myenteric Plexus Ganglia of Adult Rat Small Intestine.

The cellular components of the enteric nervous system (ENS), namely enteric neurons and glia, display plasticity and respond to environmental cues deriving from growth factors, extracellular matrix (ECM) molecules, and cell-surface molecules, both in physiological and pathological conditions. ECM, in particular, provides an important framework for the enteric microenvironment and influences the homeostasis of myenteric neuronal circuitries. Isolation of pure myenteric plexus preparations from adult tissue permits to investigate changes in the ENS involving specific ECM, such as hyaluronan. This approach is based upon the possibility to isolate myenteric ganglia from the intestinal wall of either adult animals or humans, after microdissection and subsequent enzymatic digestion of the tissue. Enteric ganglia are free of connective tissue, extracellular collagen, and blood vessels, and thus treatment of intact intestinal segments with highly purified collagenases permits ganglia isolation from the surrounding smooth muscle cells. In this chapter, we describe methods for visualizing HA in isolated primary cultures of adult rat small intestine myenteric ganglia.

Balanced Caloric Restriction Minimizes Changes Caused by Aging on the Colonic Myenteric Plexus.

Aging can promote significant morphofunctional changes in the gastrointestinal tract (GIT). Regulation of GIT motility is mainly controlled by the myenteric neurons of the enteric nervous system. Actions that aim at decreasing the aging effects in the GIT include those related to diet, with caloric restriction (CR). The CR is achieved by controlling the amount of food or by manipulating the components of the diet. Therefore, the objective of this study was to evaluate different levels of CR on the plasticity of nicotinamide adenine dinucleotide phosphate- (NADPH-) reactive myenteric neurons in the colon of Wistar rats during the aging process using ultrastructural (transmission electron microscopy) and morphoquantitative analysis. Wistar male rats (Rattus norvegicus) were distributed into 4 groups (n = 10/group): C, 6-month-old animals; SR, 18-month-old animals fed a normal diet; CRI, 18-month-old animals fed a 12% CR diet; CRII, 18-month-old animals fed a 31% CR diet. At 6 months of age, animals were transferred to the laboratory animal facility, where they remained until 18 months of age. Animals of the CRI and CRII groups were submitted to CR for 6 months. In the ultrastructural analysis, a disorganization of the periganglionar matrix with the aging was observed, and this characteristic was not observed in the animals that received hypocaloric diet. It was observed that the restriction of 12.5% and 31% of calories in the diet minimized the increase in density and cell profile of the reactive NADPH neurons, increased with age. This type of diet may be adapted against gastrointestinal disturbances that commonly affect aging individuals.

The enteric nervous system is a potential autoimmune target in multiple sclerosis.

Multiple sclerosis (MS) is a chronic autoimmune disease of the central nervous system (CNS) in young adults that has serious negative socioeconomic effects. In addition to symptoms caused by CNS pathology, the majority of MS patients frequently exhibit gastrointestinal dysfunction, which was previously either explained by the presence of spinal cord lesions or not directly linked to the autoimmune etiology of the disease. Here, we studied the enteric nervous system (ENS) in a B cell- and antibody-dependent mouse model of MS by immunohistochemistry and electron microscopy at different stages of the disease. ENS degeneration was evident prior to the development of CNS lesions and the onset of neurological deficits in mice. The pathology was antibody mediated and caused a significant decrease in gastrointestinal motility, which was associated with ENS gliosis and neuronal loss. We identified autoantibodies against four potential target antigens derived from enteric glia and/or neurons by immunoprecipitation and mass spectrometry. Antibodies against three of the target antigens were also present in the plasma of MS patients as confirmed by ELISA. The analysis of human colon resectates provided evidence of gliosis and ENS degeneration in MS patients compared to non-MS controls. For the first time, this study establishes a pathomechanistic link between the well-established autoimmune attack on the CNS and ENS pathology in MS, which might provide a paradigm shift in our current understanding of the immunopathogenesis of the disease with broad diagnostic and therapeutic implications.

Ultrastructural characteristics of myenteric plexus in patients with colorectal cancer.

INTRODUCTION: It have been found previously that colorectal cancer (CRC) is accompanied by atrophy of myenteric plexuses (MPs) localized close to the tumor. The aim of the study was to compare ultrastructure of MPs localized in the unchanged part of the colon wall distant to CRC tumor with the ultrastructure of MPs in the vicinity of CRC tumor. MATERIAL AND METHODS: The present study was conducted using post-operative material derived from 11 patients with CRC. Samples of colon wall were taken from the margin of cancer invasion and from a macroscopically unchanged segment of the large intestine, immediately fixed and processed according to the standard protocol for transmission electron microscopy studies. RESULTS: In the MPs localized in the control part of colon wall the presence of numerous unmyelinated axons and cell bodies of neurons, interstitial cells of Cajal and enteroglial cells were observed. As compared to control samples, in the MPs located close to the tumor invasion, expansion of the extracellular matrix and myelin-like structures accompanying some nerve fibers were found. The appearance of mast and plasma cells was observed within MPs in the vicinity of CRC tumor. Sporadically, apoptotic cells were present inside the MPs. CONCLUSIONS: The presence of myelin-like structures and apoptotic cells within MPs located close to tumor invasion suggests that atrophy of MPs may be caused by factors released from CRC tumor.

Technical feasibility of visualizing myenteric plexus using confocal laser endomicroscopy.

BACKGROUND AND AIM: In preceding studies, we identified that the myenteric plexus (MP) could be visualized with confocal laser endomicroscopy (CLE) by applying neural fluorescent probes lacking clinical safety profiling data from the submucosal side. In this study, we evaluated the technical feasibility of MP visualization using probe-based CLE (pCLE) from the serosal side with cresyl violet (CV), which has been used clinically for chromoendoscopy. METHODS: The dye affinity of CV for MP was first explored in an in vivo transgenic mouse model using neural crest derivatives labeled with green fluorescent protein. We also tested the feasibility of CV-assisted visualization of MP in human surgical specimens, wherein the tissue dying and pCLE observation were performed from the serosal side. In the human study, rate of MP visualization by pCLE was evaluated as the primary outcome. We also evaluated the sensitivity and specificity of MP visualization by pCLE, using pathological presence/absence of MP as the gold standard. RESULTS: We confirmed the dye affinity of CV to MP in all tested models. The MP appeared as brightly stained ladder-like structures with pCLE, and in the human study, MP was visualized in 12/14 (85.7%) samples, with 92.3% sensitivity and 100% specificity. In positive cases showing the ladder-like structure of MP by pCLE, the mean maximum and minimum widths of nerve strands were 54.3 (± 23.6) and 19.7 (± 6.0) µm, respectively. A ganglion was detected by pCLE in 10 cases (10/12, 83.3%). CONCLUSIONS: This study demonstrated the technical feasibility of visualizing the MP in real time by CV-assisted pCLE (UMIN-CTR number, UMIN000015056).

Neurovascular Interface in Porcine Small Intestine: Specific for Nitrergic rather than Nonnitrergic Neurons.

In the 1970s, by using classic histological methods, close topographical relationships between special areas of enteric ganglia and capillaries were shown in the pig. In this study, by application of double and triple immunohistochemistry, we confirmed this neurovascular interface and demonstrated that these zones are mainly confined to nitrergic neurons in the myenteric and the external submucosal plexus. In the upper small intestine of the pig, the respective neurons display type III morphology, i.e. they have long, slender and branched dendrites and a single axon. In another set of experiments, we prepared specimens for electron-microscopical analysis of these zones. Both ganglia and capillaries display continuous basement membranes, the smallest distances between them being 1,000 nm at the myenteric and 300 nm at the external submucosal level. The capillary endothelium was mostly continuous but, at the external submucosal level, scattered fenestrations were observed. This particular neurovascular relationship suggests that nitrergic neurons may require a greater amount of oxygen and/or nutrients. In guinea pig and mouse, previous ischemia/reperfusion experiments showed that nitrergic neurons are selectively damaged. Thus, a preferential blood supply of enteric nitrergic neurons may indicate that these neurons are more vulnerable in ischemia.

Distribution of acotiamide, an orally active acetylcholinesterase inhibitor, into the myenteric plexus of rat and dog stomachs.

AIMS: Acotiamide is the first-in-class drug for the treatment of functional dyspepsia. Although pharmacological and therapeutic actions of acotiamide are thought to be derived from its inhibitory effects on acetylcholinesterase (AChE), whether the concentration of acotiamide at the site of action is sufficient to inhibit AChE remains unclear. Since major site of acotiamide action is thought to be the cholinergic nerve terminals in gastric myenteric plexus, we studied the distribution of [(14)C]acotiamide into gastric myenteric plexus. MAIN METHODS: Distribution of [(14)C]acotiamide was evaluated using macro- and micro-autoradiography in rats and dogs. KEY FINDINGS: The results of macro-autoradiography showed the concentration of radioactivity was 27.9µM in rat stomach, which was 12 times higher than IC50 of acotiamide for rat AChE. Being different from rats, the distribution of radioactivity in the muscular layer was distinguishable from that in the mucosal layer in dog stomach. The concentration of radioactivity in the muscular layer of dog stomach (1.41µM) was approximately two-times lower than those in the mucosal layer, however, it was approximately 1.2 times higher than IC50 of acotiamide for dog AChE. The results of micro-autoradiography also showed the radioactivity distributed homogenously in the muscular layer of rat stomach, suggesting the concentration of radioactivity around the ganglion of myenteric plexus is similar to that in the muscular layer of stomach. SIGNIFICANCE: These findings suggest acotiamide distributes to the myenteric plexus of stomach, a putative site of acotiamide action, with adequate concentrations to inhibit AChE, in both of rat and dog stomachs.

Mechanism of aqueous fructus aurantii immaturus extracts in neuroplexus of cathartic colons.

AIM: To examine the effect of aqueous fructus aurantii immaturus (FAI) extracts on the intestinal plexus of cathartic colons. METHODS: Cathartic colons were induced in rats with dahuang, a laxative used in traditional Chinese medicine. Once the model was established (after approximately 12 wk), rats were administered mosapride (1.54 mg/kg) or various doses of aqueous FAI extracts (1-4 g/kg) for 14 d. Transit function was assessed using an ink propulsion test. Rats were then sacrificed, and the ultramicrostructure of colonic tissue was examined using transmission electron microscopy. The expression of the 5-hydroxytryptamine receptor 4 (5-HTR4) and neurofilament-H was assessed in colon tissues using real-time PCR, Western blot, and immunohistochemistry. RESULTS: Mosapride and high dose (4 g/kg) of aqueous FAI extracts significantly improved the bowel movement in cathartic colons compared to untreated model colons as measured by the intestinal transit rate (70.06 ± 7.25 and 72.02 ± 8.74, respectively, vs 64.12 ± 5.19; P < 0.05 for both). Compared to controls, the ultramicrostructure of cathartic colons showed signs of neural degeneration. Treatment with mosapride and aqueous FAI extracts resulted in recovery of ultrastructural pathology. Treatment with mosapride alone upregulated the gene and protein expression of 5-HTR4 compared to untreated controls (P < 0.05 for both). Treatment with aqueous FAI extracts (≥ 2 g/kg) increased 5-HTR4 mRNA levels (P < 0.05), but no change in protein level was observed by Western blot or immunohistochemistry. The mRNA and protein levels of neurofilament-H were significantly increased with mosapride and ≥ 2 g/kg aqueous FAI extracts compared to controls (P < 0.05 for all). CONCLUSION: Aqueous FAI extracts and mosapride strengthen bowel movement in cathartic colons via increasing the expression of 5-HTR4 and neurofilament-H.

Quantitative immunohistochemical co-localization of TRPV1 and CGRP in varicose axons of the murine oesophagus, stomach and colorectum.

In the gastrointestinal (GI) tract of mammals, endings of spinal afferent neurons with cell bodies in dorsal root ganglia (DRG) detect many stimuli, including those that give rise to pain. Many of these sensory neurons express calcitonin gene-related peptide (CGRP) and TRPV1 in their cell bodies and axons. Indeed, CGRP and TRPV1 have been widely used as immunohistochemical markers of nociceptive spinal afferent axons. Although CGRP and TRPV1 often coexist in the same axons in the GI tract, their degree of coexistence along its length has yet to be quantified. In this study, we used double-labeling immunohistochemistry to quantify the coexistence of CGRP and TRPV1 in varicose axons of the murine oesophagus, stomach and colorectum. The great majority of CGRP-immunoreactive (IR) varicosities in myenteric ganglia of the lower esophagus (97±1%) and stomach (95±1%) were also TRPV1-immunoreactive. Similarly, the majority of TRPV1-IR varicosities in myenteric ganglia of the lower esophagus (95±1%) and stomach (91±1%) were also CGRP-IR. In the colorectum similar observations were made for an intensely immunoreactive population of CGRP-IR axons, of which most (91±1%) were also TRPV1-IR. Of the TRPV1-IR axons in the colorectum, most (96±1%) contained intense CGRP-IR. Another population of axons in myenteric ganglia of the colorectum had low intensity CGRP immunoreactivity; these showed negligible co-existence with TRPV1. Our observations reveal that in the myenteric plexus of murine oesophagus, stomach and colorectum, CGRP and TRPV1 are largely expressed together.

GDNF induces synaptic vesicle markers in enteric neurons.

Regulation of intestinal motility depends on an intact synaptic vesicle apparatus. Thus, we investigated the expression of the synaptic vesicle markers synaptophysin and synaptobrevin in the human enteric nervous system (ENS) and their regulation by glial cell line-derived neurotrophic factor (GDNF) in cultured enteric neurons. Full-thickness specimens of the human colon were assessed for expression of synaptophysin and synaptobrevin and neuronal localization was assessed by dual-label immunocytochemistry with PGP 9.5. Effects of GDNF on both synaptic markers were monitored in enteric nerve cell cultures and the presence of varicosities was determined by applying electron microscopy to the cultures. Human colonic specimens showed immunoreactivity for synaptophysin and synaptobrevin in both myenteric and submucosal ganglia as well as in nerve fibers. Both synaptic vesicle markers co-localized with the neuronal marker PGP 9.5 and exhibited granular accumulation patterns in the human and rat ENS. In cultured rat myenteric neurons GDNF treatment promoted expression of both synaptic vesicle markers and the formation of neuronal varicosities. The regulation of synaptophysin and synaptobrevin in enteric neurons by GDNF argues for the induction of functional neuronal networks in culture characterized by an increase of synaptogenesis.

Diagnosis of mitochondrial neurogastrointestinal encephalopathy disease in gastrointestinal biopsies.

A 14-year-old boy with mitochondrial neurogastrointestinal encephalopathy (MNGIE) disease had a lifelong history of failure to thrive and gastrointestinal symptoms including vomiting, pain, and diarrhea, leading to progressive cachexia. At the age of 9 years, after an extensive workup, the diagnosis of Crohn disease was strongly suspected, and he underwent colonoscopy with multiple biopsies. At 11 years of age, vision change and poor balance lead to a diagnosis of leukodystrophy by magnetic resonance imaging. Investigations for metachromatic leukodystrophy, adrenal leukodystrophy, and globoid cell leukodystrophy were all negative. A diagnosis of MNGIE disease was suspected when he continued deteriorating with gastrointestinal symptoms, multiple neurologic deficits, and encephalopathy. Markedly diminished thymidine phosphorylase activity and increased thymidine plasma levels confirmed the diagnosis of MNGIE. At autopsy, megamitochondria were observed by light microscopy in submucosal and myenteric ganglion cells and in smooth muscle cells of muscularis mucosae and muscularis propria, along the entire gastrointestinal tract from the esophagus to the rectum. Megamitochondria in ganglion cells were also observed in a retrospective review of the endoscopic intestinal biopsies taken at age 9 and 13 years and in the appendectomy specimen obtained 1 month before his demise. This study corroborates the presence of megamitochondria in gastrointestinal ganglion cells in MNGIE disease, better illustrates their detailed morphology, and describes for the first time similar structures in the cytoplasm of gastrointestinal smooth muscle cells. Pathologists should be able to recognize these structures by light microscopy and be aware of their association with primary mitochondriopathies.

Automated filtering of intrinsic movement artifacts during two-photon intravital microscopy.

In vivo imaging using two-photon microscopy is an essential tool to explore the dynamic of physiological events deep within biological tissues for short or extended periods of time. The new capabilities offered by this technology (e.g. high tissue penetrance, low toxicity) have opened a whole new era of investigations in modern biomedical research. However, the potential of using this promising technique in tissues of living animals is greatly limited by the intrinsic irregular movements that are caused by cardiac and respiratory cycles and muscular and vascular tone. Here, we show real-time imaging of the brain, spinal cord, sciatic nerve and myenteric plexus of living mice using a new automated program, named Intravital_Microscopy_Toolbox, that removes frames corrupted with motion artifacts from time-lapse videos. Our approach involves generating a dissimilarity score against precalculated reference frames in a specific reference channel, thus allowing the gating of distorted, out-of-focus or translated frames. Since the algorithm detects the uneven peaks of image distortion caused by irregular animal movements, the macro allows a fast and efficient filtering of the image sequence. In addition, extra features have been implemented in the macro, such as XY registration, channel subtraction, extended field of view with maximum intensity projection, noise reduction with average intensity projections, and automated timestamp and scale bar overlay. Thus, the Intravital_Microscopy_Toolbox macro for ImageJ provides convenient tools for biologists who are performing in vivo two-photon imaging in tissues prone to motion artifacts.

Crohn's disease: ultrastructure of interstitial cells in colonic myenteric plexus.

The role of the interstitial cells of Cajal (ICC) in chronic inflammatory bowel disease, i.e., ulcerative colitis (UC) and Crohn's disease (CD), remains unclear. Ultrastructural alterations in ICC in the colonic myenteric plexus (ICC-MP) have been reported previously in UC, but descriptions of ICC-MP and other interstitial cells in the myenteric region of the colon are lacking for CD. In the present study, we characterized the ultrastructure of interstitial cells, nerves, and glial cells in the myenteric region in Crohn's colitis (CC). In comparison with controls, varicosities of the myenteric bundles were dilated and appeared to be empty. Lipid droplets and lipofuscin-bodies were prominent in glial cells and neurons. ICC-MP were scanty but, as in controls, had caveolae, prominent intermediate filaments, cytoplasmic dense bodies, and membrane-associated dense bands with a patchy basal lamina. ICC-MP were similar in the various colonic regions. ICC-MP in CC showed no signs of degeneration or cytological changes. As in controls, fibroblast-like cells had abundant coated vesicles but lacked prominent intermediate filaments and caveolae. Macrophages also appeared as in controls. In comparison with ICC-MP in UC, the cytology of ICC-MP in CC were thus undisturbed. The ultrastructural differences between UC and CC might reflect pathophysiological differences of importance for understanding pathogenetic differences between CD and UC.

Colonic endoscopic full-thickness biopsies: from the neuropathological analysis of the myenteric plexus to the functional study of neuromuscular transmission.

BACKGROUND: Better understanding of the pathophysiological mechanisms involved in severe dysmotility disorders is crucial to improve patient management and identify novel therapeutic targets. Recent studies suggested that endoscopic full-thickness biopsies (eFTBs) could be developed as an alternative to surgical biopsies. However, currently it remains unknown whether eFTBs would allow myenteric plexus analysis on whole mounts and the evaluation of neuromuscular transmission. OBJECTIVE: To determine with eFTB specimens the ability to analyze on whole mounts the key parameters of the myenteric plexus, ie, ganglia and neurons, and to perform functional evaluation of neuromuscular transmission. DESIGN: An experimental pilot study in 6 pigs was conducted in accordance with French institutional guidelines. INTERVENTION: Under general anesthesia, pigs underwent a rectosigmoidoscopy. In each pig, an eFTB was performed at 25, 30, and 35 cm from the anal margin with an EMR-based technique. Tissue specimens were immediately processed for immunohistochemical and/or functional ex vivo analysis of neuromuscular transmission. In 2 pigs, over-the-scope clips were used to seal the perforation. MAIN OUTCOME MEASUREMENTS: Feasibility of obtaining specimens containing myenteric plexus and muscularis propria, quantitative and standardized immunohistochemical evaluation of ganglia and myenteric neurons, ex vivo assessment of neuromuscular transmission and its pharmacology, and closure rate (ancillary study). RESULTS: Adequate tissue specimens were obtained in 100% of the procedures, on average, in 6±2 minutes. Immunohistochemical analysis of a whole mount of the myenteric plexus showed that each eFTB contained 14±5 ganglia and 1562±1066 myenteric neurons. In circular muscle strips, electrical field stimulation or exposure to a pharmacological agent induced a specific tissue response. A successful closure was achieved in 50% of cases. LIMITATIONS: Nonsurvival study; safety of the procedure needs to be specifically assessed and compared with recently published data. CONCLUSIONS: We demonstrate, for the first time, that full-thickness biopsy specimens obtained by using an endoscopic approach allow the performance of a precise study of the ENS phenotype on whole mounts of the myenteric plexus and the performance of functional studies such as evaluation of neuromuscular transmission. However, further studies are warranted to identify the optimal and safest endoscopic procedure before application of eFTB in humans.

Immunolocalization of membrane skeletal protein, 4.1G, in enteric glial cells in the mouse large intestine.

4.1 family proteins are membrane skeletal proteins that interact with spectrin-actin networks and intramembraneous proteins. We reported that one of them, 4.1G, was immunolocalized in myelinated nerve fibers of the mouse peripheral nervous system, especially along cell membranes of paranodes and Schmidt-Lanterman incisures in Schwann cells. In this study, to examine 4.1G's appearance in unmyelinated peripheral nerve fibers, we focused on the enteric nervous system in mouse large intestines. In intestinal tissues prepared by an "in vivo cryotechnique" followed by freeze-substitution fixation, 4.1G was immunolocalized in Auerbach's myenteric plexus and connecting nerve fiber networks. Its immunostaining was mostly colocalized with glial fibrillar acidic protein, a marker of enteric glial cells, but not with c-Kit, a marker of interstitial cells of Cajal. Using whole-mount preparation after splitting inner and outer muscle layers, the nerve fiber networks including the plexus were clearly detected by the 4.1G immunostaining. By conventional pre-embedding immunoelectron microscopy, 4.1G was detected along cell membranes of enteric glial cells and their processes surrounding axons. These indicate that 4.1G may have some roles in adhesion and/or signal transduction in unmylinated PNS nerve fibers.

Ulcerative colitis: ultrastructure of interstitial cells in myenteric plexus.

Interstitial cells of Cajal (ICC) are key regulatory cells in the gut. In the colon of patients with severe ulcerative colitis (UC), myenteric ICC had myoid ultrastructural features and were in close contact with nerve terminals. In all patients as opposed to controls, some ICC profiles showed degenerative changes, such as lipid droplets and irregular vacuoles. Nerve terminals often appeared swollen and empty. Glial cells, muscle cells, and fibroblast-like cells (FLC) showed no alterations. FLC enclosed macrophages (MLC), which were in close contact with naked axon terminals. The organization and cytological changes may be of pathophysiological significance in patients with UC.

Atrophy of the nitrergic myenteric neurons in the descending colon rats submitted to protein and vitamin deficiency / Atrofia en neuronas mientéricas nitrérgicas en el colon descendente de ratas sometidas a deficiencia de proteínas y vitaminas

Effects of protein and B-complex vitamin deficiency were assessed with respect to the morphometry of myenteric neurons in the descending colon of adult rats. Sixteen animals were divided into two groups: Control Group (CG, n=8) and Experimental Group (EG, n=8). The CG received 22 percent protein chow and the EG received 4 percent protein chow for 120 days. The descending colon was submitted to NADH- and NADPH-diaphorase technique in order to evidence nervous cells in the whole mounts preparations. In the EG, NADH-d positive neurons presented reduced nuclei, while NADPH-d positive neurons showed atrophy of the soma area (~41.7 percent) inducing an increase of the proportion occupied by the nucleus inside in the soma of these cells.

Esta investigación buscó evaluar los efectos de la desnutrición proteica y vitamínica delcomplexo B sobre aspectos morfométricos del plexo mientérico del colon descendente de ratones adultos. Dieciséis animales fueron distribuidos en dos grupos: control que recibieron ración comercial con 22 por ciento de proteína y experimental alimentados con ración de tenor proteico reducido para 8 por ciento, durante 120 días. Neuronas del plexo mientérico presentes en preparados totales fueron evidenciados a través de la técnica histoquímica de la NADH-diaforasa y de la NADPH-diaforasa. En el grupo experimental, las neuronas NADH-d positivos sufrieron reducción del núcleo celular, ya las neuronas NADPH-d sufrieron atrofia de 41,7 por ciento de la superficie de su pericarion, lo que hizo con que el núcleo celular pasase a ocupar una mayor proporción de la región trófica de las neuronas.