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In addition to brain injury stroke patients often suffer gastrointestinal complications. Neuroimmune interactions involving galectin-3, released from microglia in the brain, mediates the post-stroke pro-inflammatory response. We investigated possible consequences of stroke on the enteric nervous system and the involvement of galectin-3. We show that permanent middle cerebral artery occlusion (pMCAO) induces loss of enteric neurons in ileum and colon in galectin-3(+/+), but not in galectin-3(-/-), mice. In vitro we show that serum from galectin-3(+/+), but not from galectin-3(-/-), mice subjected to pMCAO, caused loss of C57BL/6J myenteric neurons, while myenteric neurons derived from TLR4(-/-) mice were unaffected. Further purified galectin-3 (10(-6) M) caused loss of cultured C57BL/6J myenteric neurons. Inhibitors of transforming growth factor β-activated kinase 1 (TAK1) or AMP activated kinase (AMPK) counteracted both the purified galectin-3 and the galectin-3(+/+) pMCAO serum-induced loss in vitro. Combined we show that stroke (pMCAO) triggers central and peripheral galectin-3 release causing enteric neuronal loss through a TLR4 mediated mechanism involving TAK1 and AMPK. Galectin-3 is suggested a target for treatment of post-stroke complications.

Amitriptyline, a well-known antidepressant, exerts inhibitory effect on electrically stimulated rat colon smooth muscle contraction. In this study, we investigated the signaling pathway of amitriptyline-induced inhibitory effect. Changes in isometric force of colon muscle were recorded on polygraph, and data were analyzed by measuring the inhibitory extent induced by amitriptyline. Firstly, muscles were contracted by stimulation with electric field stimulation (EFS), and then, amitriptyline was added cumulatively to determine its influence effect on EFS. Amitriptyline significantly inhibited EFS-induced contraction dose dependently. Then, the mechanism of inhibitory effect of amitriptyline was evaluated by pretreating with various antagonists such as L-NAME, methylene blue, atropine, 5-HT receptors blockers, guanethidine, prazosin, guanabenz, isoprenaline, Y27632 (Rho-kinase inhibitor), ML9 (myosin light chain kinase (MLCK) inhibitor), U73122 (PLC inhibitor), and chelerythrine (PKC inhibitor). Then, Ca(2+) channel blocker (nifedipine) and K(+)channel blockers, tetraethylammonium (TEA), 4-aminopyridine (4-AP), and glybenclamide, were used to determine the involvement of ion channels. L-NAME, guanabenz, 5HT4 receptor blocker, ML9, and Y27632 enhanced the effect of amitriptyline. Meanwhile, methylene blue, atropine, guanethidine, prazosin, methylsergide, ondansetron, U73122, and chelerythrine blocked its effect. It was also shown that nifedipine enhanced but TEA and glybenclamide blocked amitriptyline-induced inhibitory effect on EFS. Our results indicated that amitriptyline may exert inhibitory effect in response to EFS by inhibiting muscarinic receptors and then PLC-mediated PKC pathway leading to opening of ATP-sensitive potassium channel.

Background and Aim: Irritable bowel syndrome is characterized by abdominal pain and altered bowel habits and may occur following stressful events or infectious gastroenteritis such as giardiasis. Recent findings revealed a link between cholecystokinin (CCK), neurotrophin synthesis, and intestinal hyperalgesia. The aim was to investigate the role of CCK in visceral hypersensitivity using mouse models challenged with a bout of infection with Giardia lamblia or psychological stress, either alone or in combination., Methods: Abdominal pain was evaluated by visceromoter response to colorectal distension. Nerve fibers in intestinal tissues were stained using immunohistochemistry (PGP9.5). Human neuroblastoma SH-SY5Y cells incubated with bacterial-free mouse gut supernatant or recombinant CCK-8S were assessed for neurite outgrowth and nerve growth factor (NGF) production., Results: Intestinal hypersensitivity was induced by either stress or Giardia infection, and a trend of increased pain was seen following dual stimuli. Increased CCK levels and PGP9.5 immunoreactivity were found in colonic mucosa of mice following stress and/or infection. Inhibitors to the CCK-A receptor (L-364718) or CCK-B receptor (L-365260) blocked visceral hypersensitivity caused by stress, but not when induced by giardiasis. Nerve fiber elongation and NGF synthesis were observed in SH-SY5Y cells after incubation with colonic supernatants from mice given the dual stimuli, or after treatment with CCK-8S. Increased nerve fiber length by colonic supernatant and CCK-8S was attenuated by L-365260 or neutralizing anti-NGF., Conclusions: This new model successfully recapitulates intestinal hypernociception induced by stress or Giardia. Colonic CCK contributes to visceral hypersensitivity caused by stress, but not by Giardia, partly via NGF-dependent neurite outgrowth., (© 2016 Journal of Gastroenterology and Hepatology Foundation and John Wiley & Sons Australia, Ltd.)

Background: Neurons in lumbar and sacral dorsal root ganglia (DRG) comprise extrinsic sensory pathways to the distal colon and rectum, but their relative contributions are unclear. In this study, sensory innervation of the rectum and distal colon in the guinea pig was directly compared using retrograde labeling combined with immunohistochemistry., Methods: The lipophilic tracer, DiI, was injected in either the rectum or distal colon of anesthetized guinea pigs, then DRG (T6 to S5) and nodose ganglia were harvested and labeled using antisera for calcitonin gene-related peptide (CGRP) and transient receptor potential vanilloid 1(TRPV1)., Key Results: More primary afferent cell bodies were labeled from the rectum than from the distal colon. Vagal sensory neurons, with cell bodies in the nodose ganglia comprised fewer than 0.5% of labeled sensory neurons. Spinal afferents to the distal colon were nearly all located in thoracolumbar DRG, in a skewed unimodal distribution (peak at L2); fewer than 1% were located in sacral ganglia. In contrast, spinal afferents retrogradely labeled from the rectum had a bimodal distribution, with one peak at L3 and another at S2. Fewer than half of all retrogradely labeled spinal afferent neurons were immunoreactive for CGRP or TRPV1 and these included the larger traced neurons, especially in thoracolumbar ganglia., Conclusions & Inferences: In the guinea pig, both the distal colon and the rectum receive a sensory innervation from thoracolumbar ganglia. Sacral afferents innervate the rectum but not the distal colon. Calcitonin gene-related peptide immunoreactivity was detectable in fewer than half of afferent neurons in both pathways., (© 2016 John Wiley & Sons Ltd.)

Key Points: Remarkably little is known about how age affects the sensory signalling pathways in the gastrointestinal tract despite age-related gastrointestinal dysfunction being a prime cause of morbidity amongst the elderly population High-threshold gastrointestinal sensory nerves play a key role in signalling distressing information from the gut to the brain. We found that ageing is associated with attenuated high-threshold afferent mechanosensitivity in the murine colon, and associated loss of TRPV1 channel function. These units have the capacity to sensitise in response to injurious events, and their loss in ageing may predispose the elderly to lower awareness of GI injury or disease., Abstract: Ageing has a profound effect upon gastrointestinal function through mechanisms that are poorly understood. Here we investigated the effect of age upon gastrointestinal sensory signalling pathways in order to address the mechanisms underlying these changes. In vitro mouse colonic and jejunal preparations with attached splanchnic and mesenteric nerves were used to study mechanosensory and chemosensory afferent function in 3-, 12- and 24-month-old C57BL/6 animals. Quantitative RT-PCR was used to investigate mRNA expression in colonic tissue and dorsal root ganglion (DRG) cells isolated from 3- and 24-month animals, and immunohistochemistry was used to quantify the number of 5-HT-expressing enterochromaffin (EC) cells. Colonic and jejunal afferent mechanosensory function was attenuated with age and these effects appeared earlier in the colon compared to the jejunum. Colonic age-related loss of mechanosensory function was more pronounced in high-threshold afferents compared to low-threshold afferents. Chemosensory function was attenuated in the 24-month colon, affecting TRPV1 and serotonergic signalling pathways. High-threshold mechanosensory afferent fibres and small-diameter DRG neurons possessed lower functional TRPV1 receptor responses, which occurred without a change in TRPV1 mRNA expression. Serotonergic signalling was attenuated at 24 months, but TPH1 and TPH2 mRNA expression was elevated in colonic tissue. In conclusion, we saw an age-associated decrease in afferent mechanosensitivity in the mouse colon affecting HT units. These units have the capacity to sensitise in response to injurious events, and their loss in ageing may predispose the elderly to lower awareness of GI injury or disease., (© 2015 The Authors. The Journal of Physiology published by John Wiley & Sons Ltd on behalf of The Physiological Society.)

We tested the hypothesis that colonic enteric neurotransmission and smooth muscle cell (SMC) function are altered in mice fed a high-fat diet (HFD). We used wild-type (WT) mice and mice lacking the β1-subunit of the BK channel (BKβ1 (-/-)). WT mice fed a HFD had increased myenteric plexus oxidative stress, a 28% decrease in nitrergic neurons, and a 20% decrease in basal nitric oxide (NO) levels. Circular muscle inhibitory junction potentials (IJPs) were reduced in HFD WT mice. The NO synthase inhibitor nitro-l-arginine (NLA) was less effective at inhibiting relaxations in HFD compared with control diet (CD) WT mice (11 vs. 37%, P < 0.05). SMCs from HFD WT mice had depolarized membrane potentials (-47 ± 2 mV) and continuous action potential firing compared with CD WT mice (-53 ± 2 mV, P < 0.05), which showed rhythmic firing. SMCs from HFD or CD fed BKβ1 (-/-) mice fired action potentials continuously. NLA depolarized membrane potential and caused continuous firing only in SMCs from CD WT mice. Sodium nitroprusside (NO donor) hyperpolarized membrane potential and changed continuous to rhythmic action potential firing in SMCs from HFD WT and BKβ1 (-/-) mice. Migrating motor complexes were disrupted in colons from BKβ1 (-/-) mice and HFD WT mice. BK channel α-subunit protein and β1-subunit mRNA expression were similar in CD and HFD WT mice. We conclude that HFD-induced obesity disrupts inhibitory neuromuscular transmission, SMC excitability, and colonic motility by promoting oxidative stress, loss of nitrergic neurons, and SMC BK channel dysfunction., (Copyright © 2016 the American Physiological Society.)

The μ-opioid receptor (MOR) is a major regulator of gastrointestinal motility and secretion and mediates opiate-induced bowel dysfunction. Although MOR is of physiological and therapeutic importance to gut function, the cellular and subcellular distribution and regulation of MOR within the enteric nervous system are largely undefined. Herein, we defined the neurochemical coding of MOR-expressing neurons in the guinea pig gut and examined the effects of opioids on MOR trafficking and regulation. MOR expression was restricted to subsets of enteric neurons. In the stomach MOR was mainly localized to nitrergic neurons (∼88%), with some overlap with neuropeptide Y (NPY) and no expression by cholinergic neurons. These neurons are likely to have inhibitory motor and secretomotor functions. MOR was restricted to noncholinergic secretomotor neurons (VIP-positive) of the ileum and distal colon submucosal plexus. MOR was mainly detected in nitrergic neurons of the colon (nitric oxide synthase positive, 87%), with some overlap with choline acetyltransferase (ChAT). No expression of MOR by intrinsic sensory neurons was detected. [d-Ala(2), MePhe(4), Gly(ol)(5)]enkephalin (DAMGO), morphiceptin, and loperamide induced MOR endocytosis in myenteric neurons. After stimulation with DAMGO and morphiceptin, MOR recycled, whereas MOR was retained within endosomes following loperamide treatment. Herkinorin or the δ-opioid receptor agonist [d-Ala(2), d-Leu(5)]enkephalin (DADLE) did not evoke MOR endocytosis. In summary, we have identified the neurochemical coding of MOR-positive enteric neurons and have demonstrated differential trafficking of MOR in these neurons in response to established and putative MOR agonists., (Copyright © 2016 the American Physiological Society.)

Gastric hypersensitivity (GHS) and anxiety are prevalent in functional dyspepsia patients; their underlying mechanisms remain unknown largely because of lack of availability of live visceral tissues from human subjects. Recently, we demonstrated in a preclinical model that rats subjected to neonatal colon inflammation show increased basal plasma norepinephrine (NE), which contributes to GHS through the upregulation of nerve growth factor (NGF) expression in the gastric fundus. We tested the hypothesis that neonatal colon inflammation increases anxiety-like behavior and sympathetic nervous system activity, which upregulates the expression of NGF to induce GHS in adult life. Chemical sympathectomy, but not adrenalectomy, suppressed the elevated NGF expression in the fundus muscularis externa and GHS. The measurement of heart rate variability showed a significant increase in the low frequency-to-high frequency ratio in GHS vs. the control rats. Stimulus-evoked release of NE from the fundus muscularis externa strips was significantly greater in GHS than in the control rats. Tyrosine hydroxylase expression was increased in the celiac ganglia of the GHS vs. the control rats. We found an increase in trait but not stress-induced anxiety-like behavior in GHS rats in an elevated plus maze. We concluded that neonatal programming triggered by colon inflammation upregulates tyrosine hydroxylase in the celiac ganglia, which upregulates the release of NE in the gastric fundus muscularis externa. The increase of NE release from the sympathetic nerve terminals concentration dependently upregulates NGF, which proportionately increases the visceromotor response to gastric distention. Neonatal programming concurrently increases anxiety-like behavior in GHS rats., (Copyright © 2016 the American Physiological Society.)

Aim: To evaluate gut microbial dysbiosis in two visceral hypersensitive models in comparison with irritable bowel syndrome (IBS) patients and to explore the extent to which these models capture the dysbiosis of IBS patients., Methods: Visceral hypersensitivity was developed using the maternal separation (MS) rat model and post-inflammatory rat model. The visceral sensitivity of the model groups and control group was evaluated using the abdominal withdraw reflex score and electromyography in response to graded colorectal distention. The 16S ribosomal RNA gene from fecal samples was pyrosequenced and analyzed. The correlation between dysbiosis in the microbiota and visceral hypersensitivity was calculated. Positive findings were compared to sequencing data from a published human IBS cohort., Results: Dysbiosis triggered by neonatal maternal separation was lasting but not static. Both MS and post-inflammatory rat fecal microbiota deviated from that of the control rats to an extent that was larger than the co-housing effect. Two short chain fatty acid producing genera, Fusobacterium and Clostridium XI, were shared by the human IBS cohort and by the maternal separation rats and post-inflammatory rats, respectively, to different extents. Fusobacterium was significantly increased in the MS group, and its abundance positively correlated with the degree of visceral hypersensitivity. Porphyromonadaceae was a protective biomarker for both the rat control group and healthy human controls., Conclusion: The dysbiosis MS rat model and the post-inflammatory rat model captured some of the dysbiosis features of IBS patients. Fusobacterium, Clostridium XI and Porphyromonadaceae were identified as targets for future mechanistic research.

Synucleinopathies and abnormalities in the nerves of the enteric nervous system are hypothesized to be involved in age-associated motility disorders. The aim of the present study was to investigate the expression of various antigens, including α‑synuclein (Syn) and its post‑translational modified forms, in the human colon at various ages. In addition, the study aimed to correlate the expression of Syn with neurodegeneration. Immunohistochemistry was used to detect the expression of neurofilament (NF), Syn, as well as its nitrated (N) form in the healthy colonic tissue of 12 young (34.08±5.12 years), 10 middle‑aged (51.80±3.52 years), and 11 elderly (75.82±7.70 years) individuals. To the best of our knowledge, the current study is the first to demonstrate the presence of N‑Syn in the colonic tissue. N‑Syn was identified in the upper layer of the mucosa and submucosa layer. Furthermore, Syn (wild‑type) was present in the mucosa and submucosa. The number of NF‑positive neurons in the submucosal layer declined significantly with age (P<0.01). In addition, Syn and N‑Syn significantly increased during aging (P<0.01). Furthermore, a negative correlation was identified between neuron number and synucleinopathies, indicating the abnormal accumulation of both wild-type Syn and N‑Syn in the mucosa, submucosa, muscle layer and myenteric plexus. The present study demonstrates that the Syn pathology may be linked to colic neuronal degeneration during normal aging, and this link may cause functional deficits.

Background and Aim: Inflammatory bowel disease is associated with chronic abdominal pain. Transient receptor potential ankyrin 1 (TRPA1) is a well-known pain sensor expressed in primary sensory neurons. Recent studies indicate that reactive oxygen species such as hydrogen peroxide (H2 O2 ) may activate TRPA1., Methods: Colonic inflammation was induced by intra-colonic administration of trinitrobenzene sulfate (TNBS) in adult male Sprague-Dawley rats. Visceromotor response (VMR) to colorectal distention (CRD) was recorded to evaluate the visceral hyperalgesia. Rats were sacrificed 1 day after treatment with saline or TNBS; colonic tissues from the inflamed region were removed and then processed to assess the H2 O2 content. H2 O2 scavenger N-acetyl-l-cysteine or a TRPA1 antagonist, HC-030031, was intravenously administrated to the TNBS-treated rats or saline-treated rats. In a parallel experiment, intra-colonic H2 O2 -induced visceral hyperalgesia in naïve rats and the effect of intravenous HC-030031 were measured based on the VMR to CRD., Results: Trinitrobenzene sulfate treatment resulted in significant increase in VMR to CRD at day 1. The H2 O2 content in the inflamed region of the colon in TNBS-treated rats was significantly higher than that of saline-treated rats. N-acetyl-l-cysteine or HC-030031 significantly suppressed the enhanced VMR in TNBS-treated rats while saline-treated rats remained unaffected. Moreover, blockade of TRPA1 activation by HC-030031 significantly reversed the exogenous H2 O2 -induced visceral hyperalgesia., Conclusion: These results suggest that H2 O2 content of the colonic tissue is increased in the early stage of TNBS-induced colitis. The increased H2 O2 content may contribute to the visceral hyperalgesia by activating TRPA1., (© 2015 Journal of Gastroenterology and Hepatology Foundation and John Wiley & Sons Australia, Ltd.)

The postnatal period is crucial for the development of gastrointestinal (GI) functions. The enteric nervous system is a key regulator of GI functions, and increasing evidences indicate that 1) postnatal maturation of enteric neurons affect the development of GI functions, and 2) microbiota-derived short-chain fatty acids can be involved in this maturation. Although enteric glial cells (EGC) are central regulators of GI functions, the postnatal evolution of their phenotype remains poorly defined. We thus characterized the postnatal evolution of EGC phenotype in the colon of rat pups and studied the effect of short-chain fatty acids on their maturation. We showed an increased expression of the glial markers GFAP and S100β during the first postnatal week. As demonstrated by immunohistochemistry, a structured myenteric glial network was observed at 36 days in the rat colons. Butyrate inhibited EGC proliferation in vivo and in vitro but had no effect on glial marker expression. These results indicate that the EGC myenteric network continues to develop after birth, and luminal factors such as butyrate endogenously produced in the colon may affect this development., (Copyright © 2016 the American Physiological Society.)

Increased levels of pro- and anti-inflammatory cytokines were observed in various segments of histologically-intact small intestine in animal models of acute and chronic colitis. Whether these cytokines are produced locally or spread from the inflamed colon is not known. In addition, the role of gut innervation in this upregulation is not fully understood. To examine whether cytokines are produced de novo in the small intestine in two rat models of colitis; and to investigate the role of capsaicin-sensitive primary afferents in the synthesis of these inflammatory cytokines. Colitis was induced by rectal instillation of iodoacetamide (IA) or trinitrobenzene sulphonic acid (TNBS) in adult Sprague-Dawley rats. Using reverse transcriptase (RT) and real-time PCR, TNF-α, and IL-10 mRNA expression was measured in mucosal scrapings of the duodenum, jejunum, ileum and colon at different time intervals after induction of colitis. Capsaicin-sensitive primary afferents (CSPA) were ablated using subcutaneous injections of capsaicin at time 0, 8 and 32 h, and the experiment was repeated at specific time intervals to detect any effect on cytokines expression. TNF-α mRNA expression increased by 3-40 times in the different intestinal segments (p<0.05 to p<0.001), 48h after IA-induced colitis. CSPA ablation completely inhibited this upregulation in the small intestine, but not in the colon. Similar results were obtained in TNBS-induced colitis at 24 h. Intestinal IL-10 mRNA expression significantly decreased at 12 h and then increased by 6-43 times (p<0.05 to p<0.001) 48h after IA administration. This increase was abolished in rats subjected to CSPA ablation except in the colon, where IL-10 further increased by twice (p<0.05). In the TNBS group, there was 4-12- and 4-7-fold increases in small intestinal IL-10 mRNA expression at 1 and 21 days after colitis induction, respectively (both p<0.01). This increase was not observed in rats pretreated with capsaicin. Capsaicin-treated and untreated rats had comparable visual ulcer scores after colitis induction. Inflammatory cytokines are produced de novo in distant intestinal segments in colitis. CSPA fibers play a key role in the upregulation of this synthesis.

Aim: To determine if expression of colonic tryptophan hydroxylase-2 (TPH2), a surrogate marker of neuronal 5-hydroxytryptamine, is altered in Hirschsprung's-associated enterocolitis., Methods: Entire resected colonic specimens were collected at the time of pull-through operation in children with Hirschsprung's disease (HSCR, n = 12). Five of these patients had a history of pre-operative Hirschsprung's-associated enterocolitis (HAEC). Controls were collected at colostomy closure in children with anorectal malformation (n = 10). The distribution of expression of TPH2 was evaluated using immunofluorescence and confocal microscopy. Protein expression of TPH2 was quantified using western blot analysis in the deep smooth muscle layers., Results: TPH2 was co-expressed in nitrergic and cholinergic ganglia in the myenteric and submucosal plexuses in ganglionic colon in HSCR and healthy controls. Co-expression was also seen in submucosal interstitial cells of Cajal and PDGFRα(+) cells. The density of TPH2 immuno-positive fibers decreased incrementally from ganglionic bowel to transition zone bowel to aganglionic bowel in the myenteric plexus. Expression of TPH2 was reduced in ganglionic bowel in those affected by pre-operative HAEC compared to those without HAEC and healthy controls. However, expression of TPH2 was similar or high compared to controls in the colons of children who had undergone diverting colostomy for medically refractory HAEC., Conclusion: Altered TPH2 expression in colonic serotonergic nerves of patients with HSCR complicated by HAEC may contribute to intestinal secretory and motor disturbances, including recurrent HAEC.

The sensory innervation of the distal colorectum includes mechanically insensitive afferents (MIAs; ∼25%), which acquire mechanosensitivity in persistent visceral hypersensitivity and thus generate de novo input to the central nervous system. We utilized an optogenetic approach to bypass the process of transduction (generator potential) and focus on transformation (spike initiation) at colorectal MIA sensory terminals, which is otherwise not possible in typical functional studies. From channelrhodopsin2-expressing mice (driven by Advillin-Cre), the distal colorectum with attached pelvic nerve was harvested for ex vivo single-fiber recordings. Afferent receptive fields (RFs) were identified by electrical stimulation and tested for response to mechanical stimuli (probing, stroking, and stretch), and afferents were classified as either MIAs or mechanosensitive afferents (MSAs). All MIA and MSA RFs were subsequently stimulated optically and MIAs were also tested for activation/sensitization with inflammatory soup (IS), acidic hypertonic solution (AHS), and/or bile salts (BS). Responses to pulsed optical stimuli (1-10 Hz) were comparable between MSAs and MIAs whereas 43% of MIAs compared with 86% of MSAs responded tonically to stepped optical stimuli. Tonic-spiking MIAs responded preferentially to AHS (an osmotic stimulus) whereas non-tonic-spiking MIAs responded to IS (an inflammatory stimulus). A significant proportion of MIAs were also sensitized by BS. These results reveal transformation as a critical factor underlying the differences between MIAs (osmosensors vs. inflammatory sensors), revealing a previously unappreciated heterogeneity of MIA endings. The current study draws attention to the sensory encoding of MIA nerve endings that likely contribute to afferent sensitization and thus have important roles in visceral pain., (Copyright © 2016 the American Physiological Society.)

Background: Visceral hypersensitivity in the inflamed gut is related partly to the effects of peripheral neurotrophic factors (NTFs) on local afferent neurons. However, alterations in sensory afferents of distant areas remain unexplored. Using the Trichinella spiralis infection model, which causes a jejunitis, we investigated the remodeling of colonic afferents and the potential role of NTFs., Methods: Rats were infected with T. spiralis. Inflammatory-like changes, mucosal mast cells (MMCs) dynamics, and expression of nerve growth factor and glial cell line-derived NTFs (glial cell-derived neurotrophic factor, artemin, and neurturin) were determined in the colon up to day 30 postinfection. Functional responses of colonic afferents were determined assessing changes in the expression of sensory-related markers in thoracolumbar (TL)/lumbosacral (LS) dorsal root ganglias (DRGs) following intracolonic capsaicin., Key Results: Trichinella spiralis induced an inflammatory-like response within the colon, partly resolved at day 30 postinfection, except for a persistent MMC infiltrate. While the jejunum of infected animals showed an up-regulation in the expression of NTFs, a transitory down-regulation was observed in the colon. Overall, T. spiralis effects on DRGs gene expression were restricted to a transient down-regulation of TPRV1. Stimulation with intracolonic capsaicin induced a down-regulation of TRPV1 levels in TL and LS DRGs, an effect enhanced in LS DRGs of infected animals, regardless the postinfection time considered., Conclusions & Inferences: During intestinal inflammation, spread morphological and functional alterations, including remodeling of visceral afferents, are observed outside the primary region affected by the insult. Similar mechanisms might be operating in states of widespread alterations of visceral sensitivity., (© 2016 John Wiley & Sons Ltd.)

Serosal application of benzalkonium chloride (BAC) has been previously applied to produce a model of aganglionosis; however, confusion remains regarding the extent of chemical ablation of enteric myenteric plexus after BAC treatment. The time sequence of BAC-induced effects on the myenteric plexus of the rat colon was determined and followed the morphologic changes. After sacrifice of animals 7, 14, 28, 56, 84 or 168 days postintervention, colonic tissue samples were removed, fixed in formalin, and cut into 5-μm longitudinal sections for histological analysis. The neural analysis was used to re-evaluate BAC treatments for the appropriate model. Compared with rats in sham groups, rats in 0.1 %-30-min BAC group maintained only 15.27 ± 4.80 % of ganglia per section in a 1-cm/5-μm slice and 11.76 ± 2.30 % of ganglionic cells after 28 days, the lower and stable number of ganglionic cells between Day 7 and 84 (from 11.67 ± 2.10 to 19.05 ± 5.10 %). Although an increase, ganglionic cell numbers did not recover at Day168 when compared with the numbers in sham groups. The results showed that characteristics of rats in the 0.1 %-30-min BAC group between Day 7 and 84 most closely kept in stable state, suggesting that these treatment parameters are ideal for producing a hypoganglia model of hypoganglionosis.

The co-occurrence of multiple pathologies in the pelvic viscera in the same patient, such as, irritable bowel syndrome and interstitial cystitis, indicates the complexity of viscero-visceral interactions and the necessity to study these interactions under multiple pathological conditions. In the present study, the effect of distal colon irritation (DCI) on the urinary bladder interaction with distal esophagus distention (DED), distal colon distention (DCD), and electrical stimulation of the abdominal branches of vagus nerve (abd-vagus) were investigated using cystometry parameters. The DCI significantly decreased the intercontraction time (ICT) by decreasing the storage time (ST); nonetheless, DED and Abd-vagus were still able to significantly decrease the ICT and ST following DCI. However, DCD had no effect on ICT following the DCI. The DCI, also, significantly decreased the Intravesical pressure amplitude (P-amplitude) by increasing the resting pressure (RP). Although DED has no effect on the P-amplitude, both in the intact and the irritated animals, the abd-vagus significantly increased the P-amplitude following DCI by increasing the maximum pressure (MP). In the contrary, 3mL DCD significantly increased the P-amplitude by increasing the MP and lost that effect following the DCI. Concerning the pressure threshold (PT), none of the stimuli had any significant changes in the intact animals. However, DCI significantly decreased the PT, also, the abd-vagus and 3mL DCD significantly decreased the PT. The results of this study indicate that chemical irritation of colon complicates the effects of mechanical irritation of esophagus and colon on urinary bladder function.

Intestinal epithelial secretion is coordinated by the submucosal plexus (SMP). Chemical mediators from SMP regulate the immunobiological response and direct actions against infectious agents. Toxoplasma gondii is a worldwide parasite that causes toxoplasmosis. This study aimed to determine the effects of chronic infection with T. gondii on the morphometry of the mucosa and the submucosal enteric neurons in the proximal colon of rats. Male adult rats were distributed into a control group (n = 10) and an infected group (n = 10). Infected rats received orally 500 oocysts of T. gondii (ME-49). After 36 days, the rats were euthanized and samples of the proximal colon were processed for histology to evaluate mucosal thickness in sections. Whole mounts were stained with methylene blue and subjected to immunohistochemistry to detect vasoactive intestinal polypeptide. The total number of submucosal neurons decreased by 16.20%. Vasoactive intestinal polypeptide-immunoreactive neurons increased by 26.95%. Intraepithelial lymphocytes increased by 62.86% and sulfomucin-producing goblet cells decreased by 22.87%. Crypt depth was greater by 43.02%. It was concluded that chronic infection with T. gondii induced death and hypertrophy in the remaining submucosal enteric neurons and damage to the colonic mucosa of rats., (Copyright © 2016 Elsevier Inc. All rights reserved.)

Purpose: Despite having optimal pull-through (PT) surgery for Hirschsprung's disease (HSCR), many patients experience persistent bowel symptoms with no mechanical/histopathological cause. Murine models of HSCR suggest that expression of key neurotransmitters is unbalanced proximal to the aganglionic colonic segment. We aimed to investigate expression of key enteric neurotransmitters in the colon of children with HSCR., Methods: Full-length PT specimens were collected fresh from children with HSCR (n=10). Control specimens were collected at colostomy closure from children with anorectal malformation (n=8). The distributions of neuronal nitric oxide synthase (nNOS), choline acetyltransferase (ChAT), vasoactive intestinal peptide (VIP), and substance P (SP) were evaluated using immunofluorescence and confocal microscopy. Neurotransmitter quantification was with Western blot analysis., Results: ChAT expression was high in aganglionic bowel and transition zone but reduced in ganglionic bowel in HSCR relative to controls. Conversely, nNOS expression was markedly reduced in aganglionic bowel but high in ganglionic bowel in HSCR relative to controls. VIP expression was similar in ganglionic HSCR and control colon. SP expression was similar in all tissue types., Conclusion: Imbalance of key excitatory and inhibitory neurotransmitters in the ganglionic bowel in HSCR may explain the basis of bowel dysmotility after an optimal pull-through operation in some patients., (Copyright © 2016 Elsevier Inc. All rights reserved.)

Aim: To investigate the effect and mechanism of stimulation of the hypothalamic paraventricular nucleus with glutamate acid in rats with ulcerative colitis (UC)., Methods: The rats were anesthetized with 10% chloral hydrate via abdominal injection and treated with an equal volume of TNBS + 50% ethanol enema, injected into the upper section of the anus with the tail facing up. Colonic damage scores were calculated after injecting a certain dose of glutamic acid into the paraventricular nucleus (PVN), and the effect of the nucleus tractus solitarius (NTS) and vagus nerve in alleviating UC injury through chemical stimulation of the PVN was observed in rats. Expression changes of C-myc, Apaf-1, caspase-3, interleukin (IL)-6, and IL-17 during the protection against UC injury through chemical stimulation of the PVN in rats were detected by Western blot. Malondialdehyde (MDA) content and superoxide dismutase (SOD) activity in colon tissues of rats were measured by colorimetric methods., Results: Chemical stimulation of the PVN significantly reduced UC in rats in a dose-dependent manner. The protective effects of the chemical stimulation of the PVN on rats with UC were eliminated after chemical damage to the PVN. After glutamate receptor antagonist kynurenic acid was injected into the PVN, the protective effects of the chemical stimulation of the PVN were eliminated in rats with UC. After AVP-Vl receptor antagonist ([Deamino-penl, val4, D-Arg8]-vasopressin) was injected into NTS or bilateral chemical damage to NTS, the protective effect of the chemical stimulation of PVN on UC was also eliminated. After chemical stimulation of the PVN, SOD activity increased, MDA content decreased, C-myc protein expression significantly increased, caspase-3 and Apaf-1 protein expression significantly decreased, and IL-6 and IL-17 expression decreased in colon tissues in rats with UC., Conclusion: Chemical stimulation of the hypothalamic PVN provides a protective effect against UC injury in rats. Hypothalamic PVN, NTS and vagus nerve play key roles in this process.

Aim: To study differences in the visceral sensitivity of the colonic mucosa between patients with diarrhea-predominant irritable bowel syndrome (IBS-D) and those with ulcerative colitis (UC) in remission and to relate these differences with changes in the 5-hydroxytryptophan (5-HT) signaling pathway., Methods: Gastrointestinal symptoms were used to determine the clinical symptom scores and rectal visceral sensitivity of patients with IBS-D and patients with UC in remission. Blood levels of 5-HT and 5-hydroxyindoleacetic acid (5-HIAA) were measured using an HPLC-electrochemical detection system. The levels of 5-HT 3 receptor (3R), 4R, and 7R mRNAs in colonic biopsy samples were detected using reverse transcription-polymerase chain reaction. The protein expression of TPH1 was analyzed by Western blot and immunohistochemistry., Results: Abdominal pain or discomfort, stool frequency, and the scores of these symptoms in combination with gastrointestinal symptoms were higher in the IBS-D and UC groups than in the control groups. However, no significant differences were observed between the IBS-D and UC remission groups. With respect to rectal visceral sensitivity, the UC remission and IBS-D groups showed a decrease in the initial perception threshold, defecating threshold and pain threshold. However, these groups exhibited significantly increased anorectal relaxation pressure. Tests examining the main indicators of the 5-HT signaling pathway showed that the plasma 5-HT levels, 5-HIAA concentrations, TPH1 expression in the colonic mucosa, and 5-HT3R and 5-HT5R expression were increased in both the IBS-D and the UC remission groups; no increases were observed with respect to 5-HT7R expression., Conclusion: The IBS-D and UC groups showed similar clinical symptom scores, visceral sensitivity, and levels of serotonin signaling pathway indicators in the plasma and colonic mucosa. However, the pain threshold and 5-HT7R expression in the colonic mucosa were significantly different between these groups. The results reveal that (1) IBS-D and UC are related to visceral sensitivity pathogenesis and the clinical manifestations of these conditions and (2) the observed differences in visceral hypersensitivity are possibly due to differences in levels of the 5-HT7 receptor, a component of the 5-HT signaling pathway.

We have recently demonstrated that orexin acts centrally through the brain orexin 1 receptors to induce an antinociceptive action against colonic distension in conscious rats. Adenosine signaling is capable of inducing an antinociceptive action against somatic pain; however, the association between changes in the adenosinergic system and visceral pain perception has not been investigated. In the present study, we hypothesized that the adenosinergic system may be involved in visceral nociception, and thus, adenosine signaling may mediate orexin-induced visceral antinociception. Visceral sensation was evaluated based on the colonic distension-induced abdominal withdrawal reflex (AWR) in conscious rats. Subcutaneous (0.04-0.2mg/rat) or intracisternal (0.8-4μg/rat) injection of N(6)-cyclopentyladenosine (CPA), an adenosine A1 receptor (A1R) agonist, increased the threshold volume of colonic distension-induced AWR in a dose-dependent manner, thereby suggesting that CPA acts centrally in the brain to induce an antinociceptive action against colonic distension. Pretreatment with theophylline, an adenosine antagonist, or 1,3-dipropyl-8-cyclopentylxanthine, an A1R antagonist, subcutaneously injected potently blocked the centrally injected CPA- or orexin-A-induced antinociceptive action against colonic distension. These results suggest that adenosinergic signaling via A1Rs in the brain induces visceral antinociception and that adenosinergic signaling is involved in the central orexin-induced antinociceptive action against colonic distension., (Copyright © 2016 Elsevier B.V. All rights reserved.)

Purpose: Many studies have demonstrated the convergence of vagal inputs into brainstem centers with inputs from the urinary bladder and colon, as well as the convergence of vagal inputs into other centers controlling the urinary bladder and colon reflexes. However, the effect of the vagal inputs on the interaction between the urinary bladder and other pelvic organs has not been studied. In this study, the effect of bilateral cervical vagotomy on the distal colon to urinary bladder reflex was examined., Methods: Changes to cystometry parameters in response to increased distal colon distensions (1, 2, and 3 ml) were tested in urethane-anesthetized male rats with or without bilateral cervical vagotomy., Results: In animals with intact vagus nerves, 1 and 2 ml distal colon distentions had no significant effects on micturition frequency; however, 3 ml distal colon distention significantly decreased the frequency of micturition cycles. Also, 3 ml distal colon distention inhibited micturition cycles in 37.5 % of these animals. On the other hand, following cervical vagotomy, 1 ml distal colon distention was enough to significantly decrease the frequency of micturition cycles and to inhibit the cycles in 75 % of the animals., Conclusion: These results demonstrate the presence of supraspinal inhibitory regulation, via the vagus nerve, over the distal colon to urinary bladder inhibitory reflex.

Gastric hypersensitivity is one of the key contributors to the postprandial symptoms of epigastric pain/discomfort, satiety, and fullness in functional dyspepsia patients. Epidemiological studies found that adverse early-life experiences are risk factors for the development of gastric hypersensitivity. Preclinical studies found that neonatal colon inflammation elevates plasma norepinephrine (NE), which upregulates expression of nerve growth factor (NGF) in the muscularis externa of the gastric fundus. Our goal was to investigate the cellular mechanisms by which NE upregulates the expression of NGF in gastric hypersensitive (GHS) rats, which were subjected previously to neonatal colon inflammation. Neonatal colon inflammation upregulated NGF protein, but not mRNA, in the gastric fundus of GHS rats. Western blotting showed upregulation of p110γ of phosphatidylinositol 4,5-bisphosphate 3-kinase (PI3K), phosphoinositide-dependent kinase-1 (PDK1), pAKT(Ser473), and phosphorylated 4E-binding protein (p4E-BP1)(Thr70), suggesting AKT activation and enhanced NGF protein translation. AKT inhibitor MK-2206 blocked the upregulation of NGF in the fundus of GHS rats. Matrix metalloproteinase 9 (MMP-9), the major NGF-degrading protease, was suppressed, indicating that NGF degradation was impeded. Incubation of fundus muscularis externa with NE upregulated NGF by modulating the protein translation and degradation pathways. Yohimbine, an α2-adrenergic receptor antagonist, upregulated plasma NE and NGF expression by activating the protein translation and degradation pathways in naive rats. In contrast, a cocktail of adrenergic receptor antagonists suppressed the upregulation of NGF by blocking the activation of the protein translation and degradation pathways. Our findings provide evidence that the elevation of plasma NE induces NGF expression in the gastric fundus., (Copyright © 2016 the American Physiological Society.)

Isolectin B4-binding (IB4+) dorsal root ganglion (DRG) neurons are distinct from peptidergic DRG neurons in their terminal location in the spinal cord and respective contributions to various classes and modalities of nociception. In DRG neurons innervating the mouse colon (c-DRG neurons), the reported proportion of IB4+ population is inconsistent across studies, and little is known regarding their role in colorectal mechanonociception. To address these issues, in C57BL/6J mice, we quantified IB4+ binding after labeling c-DRG neurons with Fast Blue and examined functional consequences of ablating these neurons by IB4-conjugated saporin. Sixty-one percent of Fast Blue-labeled neurons in the L6 DRG were IB4+, and 95% of these IB4+ c-DRG neurons were peptidergic. Intrathecal administration of IB4-conjugated saporin reduced the proportion of IB4+ c-DRG neurons to 37%, which was due to the loss of c-DRG neurons showing strong to medium IB4+ intensity; c-DRG neurons with weak IB4+ intensity were spared. However, this loss altered neither nociceptive behaviors to colorectal distension nor the relative proportions of stretch-sensitive colorectal afferent classes characterized by single-fiber recordings. These findings demonstrate that more than 1 half of viscerosensory L6 c-DRG neurons in C57BL/6J mouse are IB4+ and suggest, in contrast to the reported roles of IB4+/nonpeptidergic neurons in cutaneous mechanonociception, c-DRG neurons with strong-to-medium IB4+ intensity do not play a significant role in colorectal mechanonociception.

Background: Current transgenic animal models of Hirschsprung disease are restricted by limited survival and need for special dietary care. We used small animal colonoscopy to produce chemically ablated enteric nervous system in the distal colon and rectum of normal mice., Materials and Methods: Adult C57BL/6 mice underwent colonoscopy with submucosal injection of 75-100 μL of saline (n = 2) or 0.002% (n = 2), 0.02% (n = 15), or 0.2% (n = 2) benzalkonium chloride (BAC). Each mouse received 1-3 injections in the distal colon and rectum. Mice were sacrificed on postprocedure day 7 or 28. Injection sites were analyzed histologically and with immunostaining for β-tubulin III., Results: Submucosal injection of 0.02% BAC resulted in megacolon and obliteration of 82 ± 8.8% of myenteric ganglia at the injection site on postprocedure day 7 compared with normal colon. This effect was sustained until day 28. Injection of 0.002% BAC had little effect on the myenteric neuronal network at these time points. Multiple injections of 0.002% or 0.02% BAC (up to three injections per mouse) were well tolerated. Injection of 0.2% BAC caused acute toxicity or death., Conclusions: A novel model of chemically ablated enteric nervous system in the mouse colon and rectum is introduced. This model can be valuable in evaluating targeted cell delivery therapies for Hirschsprung disease., (Copyright © 2016 Elsevier Inc. All rights reserved.)

Purpose: Tissue-engineered colon (TEC) might potentially replace absent or injured large intestine, but the enteric nervous system (ENS), a key component, has not been investigated. In various enteric neuropathic diseases in which the TEC is derived from aganglionic donor colon, the resulting construct might also be aganglionic, limiting tissue engineering applications in conditions such as Hirschsprung disease (HD). We hypothesized that TEC might contain a diverse population of enteric neuronal subtypes, and that aganglionic TEC can be populated by neurons and glia when supplemented with ENS progenitor cells in the form of neurospheres., Materials and Methods: Human and murine organoid units (OU) and multicellular clusters containing epithelium and mesenchyme were isolated from both mouse and human donor tissues, including from normally innervated and aganglionic colon. The OU were seeded onto a biodegradable scaffold and implanted within a host mouse, resulting in the growth of TEC. Aganglionic murine and human OU were supplemented with cultured neurospheres to populate the absent ENS not provided by the OU to rescue the HD phenotype., Results: TEC demonstrated abundant smooth muscle and clusters of neurons and glia beneath the epithelium and deeper within the mesenchyme. Motor and afferent neuronal subtypes were identified in TEC. Aganglionic OU formed TEC with absent neural elements, but neurons and glia were abundant when aganglionic OU were supplemented with ENS progenitor cells., Conclusion: Murine and human TEC contain key components of the ENS that were not previously identified, including glia, neurons, and fundamental neuronal subtypes. TEC derived from aganglionic colon can be populated with neurons and glia when supplemented with neurospheres. Combining tissue engineering and cellular replacement therapies represents a new strategy for treating enteric neuropathies, particularly HD.

In 1899, Bayliss and Starling determined that the innervation of the intestines differs from that of other organs. They found that local neuronal networks are capable of generating reflex responses without the involvement of the central nervous system (Bayliss and Starling 1899). Once this unique feature of the enteric nervous system (ENS) was identified, it took roughly a century for enteric neurobiologists to accomplish the task of being able to identify the components of this "intrinsic neural mechanism", including intrinsic primary afferent neuron, ascending and descending interneuron, and excitatory and inhibitory motor neurons (Bayliss and Starling 1899). Once this was possible, we and others began to investigate the intrinsic circuitry of the colon and ileum to systematically determine the cellular mechanisms that explain the changes in motility and secretion that occur in intestinal inflammation. We wanted to establish what changes occur in the enteric neural circuitry, where they occur, the mechanisms responsible for these changes, and how these changes in the neural circuitry impact intestinal function.

Background: Diabetic neuropathy in visceral organs such as the gastrointestinal (GI) tract is still poorly understood, despite that GI symptoms are among the most common diabetic complications. The present study was designed to explore the changes in visceral sensitivity and the underlying functional and morphological deficits of the sensory nerves in short-term diabetic rats. Here, we compared the colorectal distension (CRD)-induced visceromotor response (VMR, an index of visceral pain) in vivo, the mechanosensitivity of colonic afferents ex vivo as well as the expression of protein gene product (PGP) 9.5 and calcitonin gene-related peptide (CGRP) in colon between diabetic (3-6 weeks after streptozotocin injection) and control (age-matched vehicle injection) rats., Results: VMR was markedly decreased in the diabetic compared to the control rats. There was a significant decrease in multiunit pelvic afferent nerve responses to ramp distension of the ex vivo colon and single unit analysis indicated that an impaired mechanosensitivity of low-threshold and wide dynamic range fibers may underlie the afferent hyposensitivity in the diabetic colon. Fewer PGP 9.5- or CGRP-immunoreactive fibers and lower protein level of PGP 9.5 were found in the colon of diabetic rats., Conclusions: These observations revealed the distinctive feature of colonic neuropathy in short-term diabetic rats that is characterized by a diminished sensory innervation and a blunted mechanosensitivity of the remnant sensory nerves.

Hirschsprung's disease (HSCR) causes functional intestinal obstruction due to the absence of the enteric nervous system (ENS) in the distal bowel and is usually diagnosed shortly after birth or during childhood. While several genetic and nongenetic factors have been linked to HSCR, the underlying mechanisms that prevent ENS precursors from colonizing distal bowel during fetal development are not completely understood in many affected children. In this issue of the JCI, Soret and colleagues identify a new mechanism that causes HSCR-like disease in mice and involves deposition of excess collagen VI in the intestine by migrating ENS precursors as they colonize fetal bowel. Remarkably, their findings may explain some of the so-called missing heritability of HSCR and suggest a mechanism for increased HSCR incidence in children with Down syndrome (trisomy 21).

The gastrointestinal tract is innervated by extrinsic sympathetic, parasympathetic and sensory nerve fibers as well as by intrinsic fibers from the neurons in myenteric and submucosal ganglia embedded into the gastrointestinal wall. Morphological and functional studies of intestinal innervation in animal models are important for understanding the pathophysiology of inflammatory bowel disease (IBD). The recently established Winnie mouse model of spontaneous chronic colitis caused by a point mutation in the Muc2 mucin gene develops inflammation due to a primary epithelial defect. Winnie mice display symptoms of diarrhea, ulcerations and rectal bleeding similar to those in IBD. In this study, we investigated myenteric neurons, noradrenergic, cholinergic and sensory nerve fibers in the distal colon of Winnie (Win/Win) mice compared to C57/BL6 and heterozygote littermates (Win/Wt) using histological and immunohistochemical methods. All Win/Win mice used in this study had inflammation with signs of mucosal damage, goblet cell loss, thickening of muscle and mucosal layers, and increased CD45-immunoreactivity in the distal colon. The density of sensory, cholinergic and noradrenergic fibers innervating the myenteric plexus, muscle and mucosa significantly decreased in the distal colon of Win/Win mice compared to C57/BL6 and Win/Wt mice, while the total number of myenteric neurons as well as subpopulations of cholinergic and nitrergic neurons remained unchanged. In conclusion, changes in the colon morphology and innervation found in Winnie mice have multiple similarities with changes observed in patients with ulcerative colitis.

Objective: To investigate the expression of α-synuclein in colonic biopsies of patients with idiopathic REM sleep behavior disorder (iRBD) and address if α-synuclein immunostaining of tissue obtained via colonic biopsies holds promise as a diagnostic biomarker for prodromal Parkinson disease (PD)., Methods: Patients with iRBD, patients with PD, and healthy controls were prospectively recruited to undergo colonic biopsies for comparison of α-synuclein immunoreactivity patterns between the groups by using 2 different antibodies., Results: There was no difference in colonic mucosal and submucosal immunostaining between groups using the 15G7 α-synuclein antibody, which was found in almost all participants enrolled in this study. By contrast, immunostaining for serine 129-phosphorylated α-synuclein (pSyn) in submucosal nerve fibers or ganglia was found in none of 14 controls but was observed in 4 of 17 participants with iRBD and 1 out of 19 patients with PD., Conclusions: The present findings of pSyn immunostaining of colonic biopsies in a substantial proportion of iRBD participants raise the possibility that this tissue marker may be a suitable candidate to study further as a prodromal PD marker in at-risk cohorts., (© 2015 American Academy of Neurology.)

Intestinal neuronal dysplasia type B (IND) denotes an increased proportion of hyperplastic submucosal ganglia, as resolved histochemically in 15-μm-thick frozen sections. IND has been reported proximal to the aganglionic segment in patients with Hirschsprung disease (HSCR) and is putatively associated with a higher rate of postsurgical dysmotility. We developed and validated histological criteria to diagnose IND-like submucosal ganglion cell hyperplasia (IND-SH) in paraffin sections and used the approach to study the incidence and clinical and/or genetic associations of IND-SH at the proximal margins of HSCR pull-through resection specimens. Full-circumference paraffin sections from the proximal margins of 64 HSCR colonic pull-through specimens and 24 autopsy controls were immunostained for neuron-specific Hu antigen, and nucleated ganglion cells in each submucosal ganglion were counted. In controls, an age-related decline in the relative abundance of "giant" ganglia (≥7 nucleated Hu-positive [Hu+] ganglion cells) was observed. A conservative diagnostic threshold for IND-SH (control mean ± 3× standard deviation) was derived from 15 controls less than 25 weeks of age. No control exceeded this threshold, whereas in the same age range, IND-SH was observed at the proximal margins in 15% (7 of 46) of HSCR resections, up to 15 cm proximal to the aganglionic segment. No significant correlation was observed between IND-SH and length of or distance from the aganglionic segment, sex, trisomy 21, RET or SEMA3C/D polymorphisms, or clinical outcome, but analysis of more patients, with better long-term follow-up will be required to clarify the significance of this histological phenotype.

Background & Aims: The therapeutic benefits of mesenchymal stem cells (MSCs), such as homing ability, multipotent differentiation capacity and secretion of soluble bioactive factors which exert neuroprotective, anti-inflammatory and immunomodulatory properties, have been attributed to attenuation of autoimmune, inflammatory and neurodegenerative disorders. In this study, we aimed to determine the earliest time point at which locally administered MSC-based therapies avert enteric neuronal loss and damage associated with intestinal inflammation in the guinea-pig model of colitis., Methods: At 3 hours after induction of colitis by 2,4,6-trinitrobenzene-sulfonate (TNBS), guinea-pigs received either human bone marrow-derived MSCs, conditioned medium (CM), or unconditioned medium by enema into the colon. Colon tissues were collected 6, 24 and 72 hours after administration of TNBS. Effects on body weight, gross morphological damage, immune cell infiltration and myenteric neurons were evaluated. RT-PCR, flow cytometry and antibody array kit were used to identify neurotrophic and neuroprotective factors released by MSCs., Results: MSC and CM treatments prevented body weight loss, reduced infiltration of leukocytes into the colon wall and the myenteric plexus, facilitated repair of damaged tissue and nerve fibers, averted myenteric neuronal loss, as well as changes in neuronal subpopulations. The neuroprotective effects of MSC and CM treatments were observed as early as 24 hours after induction of inflammation even though the inflammatory reaction at the level of the myenteric ganglia had not completely subsided. Substantial number of neurotrophic and neuroprotective factors released by MSCs was identified in their secretome., Conclusion: MSC-based therapies applied at the acute stages of TNBS-induced colitis start exerting their neuroprotective effects towards enteric neurons by 24 hours post treatment. The neuroprotective efficacy of MSC-based therapies can be exerted independently to their anti-inflammatory effects.

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 circular muscle 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 (ChAT), 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, ChAT, 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 ChAT, SP, VIP or NOS. EM-2-IR nerve fibers coursed near ChAT-IR neurons, and some of these fibers were even distributed around ChAT-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 ChAT, 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.

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.

Background & Aims: In mice, activation of the transient receptor potential cation channels (TRP) TRPV1, TRPV4, and TRPA1 causes visceral hypersensitivity. These receptors and their agonists might be involved in development of irritable bowel syndrome (IBS). We investigated whether polyunsaturated fatty acid (PUFA) metabolites, which activate TRPs, are present in colon tissues from patients with IBS and act as endogenous agonists to induce hypersensitivity., Methods: We analyzed colon biopsy samples from 40 patients with IBS (IBS biopsies) and 11 healthy individuals undergoing colorectal cancer screening (controls), collected during colonoscopy at the University of Bologna, Italy. Levels of the PUFA metabolites that activate TRPV1 (12-hydroperoxyeicosatetraenoic acid, 15-hydroxyeicosatetraenoic acid, 5-hydroxyeicosatetraenoic acid, and leukotriene B4), TRPV4 (5,6-epoxyeicosatrienoic acid [EET] and 8,9-EET), and TRPA1 (PGA1, 8-iso-prostaglandin A2, and 15-deoxy-Δ-prostaglandin J2) were measured in biopsies and their supernatants using liquid chromatography and tandem mass spectrometry; we also measured levels of the PUFA metabolites prostaglandin E2 (PGE2) and resolvins. C57Bl6 mice were given intrathecal injections of small interfering RNAs to reduce levels of TRPV4, or control small interfering RNAs, along with colonic injections of biopsy supernatants; visceral hypersensitivity was measured based on response to colorectal distension. Mouse sensory neurons were cultured and incubated with biopsy supernatants and lipids extracted from biopsies or colons of mice. Immunohistochemistry was used to detect TRPV4 in human dorsal root ganglia samples (from the National Disease Research Interchange)., Results: Levels of the TRPV4 agonist 5,6-EET, but not levels of TRPV1 or TRPA1 agonists, were increased in IBS biopsies compared with controls; increases correlated with pain and bloating scores. Supernatants from IBS biopsies, but not from controls, induced visceral hypersensitivity in mice. Small interfering RNA knockdown of TRPV4 in mouse primary afferent neurons inhibited the hypersensitivity caused by supernatants from IBS biopsies. Levels of 5,6-EET and 15-HETE were increased in colons of mice with, but not without, visceral hypersensitivity. PUFA metabolites extracted from IBS biopsies or colons of mice with visceral hypersensitivity activated mouse sensory neurons in vitro, by activating TRPV4. Mouse sensory neurons exposed to supernatants from IBS biopsies produced 5,6-EET via a mechanism that involved the proteinase-activated receptor-2 and cytochrome epoxygenase. In human dorsal root ganglia, TPV4 was expressed by 35% of neurons., Conclusions: Colon tissues from patients with IBS have increased levels of specific PUFA metabolites. These stimulate sensory neurons from mice and generate visceral hypersensitivity via activation of TRPV4., (Copyright © 2015 AGA Institute. Published by Elsevier Inc. All rights reserved.)

Histamine is a mast cell mediator released e.g. during food allergy. The aim of the project was to identify the effect of histamine on rat submucosal neurons and the mechanisms involved. Cultured submucosal neurons from rat colon express H1, H2 and H3 receptors as shown by immunocytochemical staining confirmed by reverse transcriptase polymerase chain reaction (RT-PCR) with messenger RNA (mRNA) isolated from submucosal homogenates as starting material. Histamine evoked a biphasic rise of the cytosolic Ca(2+) concentration in cultured submucosal neurons, consisting in a release of intracellularly stored Ca(2+) followed by an influx from the extracellular space. Although agonists of all three receptor subtypes evoked an increase in the cytosolic Ca(2+) concentration, experiments with antagonists revealed that mainly H1 (and to a lesser degree H2) receptors mediate the response to histamine. In coculture experiments with RBL-2H3 cells, a mast cell equivalent, compound 48/80, evoked an increase in the cytosolic Ca(2+) concentration of neighbouring neurons. Like the response to native histamine, the neuronal response to the mast cell degranulator was strongly inhibited by the H1 receptor antagonist pyrilamine and reduced by the H2 receptor antagonist cimetidine. In rats sensitized against ovalbumin, exposure to the antigen induced a rise in short-circuit current (I sc) across colonic mucosa-submucosa preparations without a significant increase in paracellular fluorescein fluxes. Pyrilamine strongly inhibited the increase in I sc, a weaker inhibition was observed after blockade of protease receptors or 5-lipoxygenase. Consequently, H1 receptors on submucosal neurons seem to play a pivotal role in the communication between mast cells and the enteric nervous system.

In the porcine colon, the submucous plexus is divided into an inner submucous plexus (ISP) on the epithelial side and an outer submucous plexus (OSP) on the circular muscle side. Although both plexuses are probably involved in the regulation of epithelial functions, they might differ in function and neurochemical coding according to their localization. Therefore, we examined expression and co-localization of different neurotransmitters and neuronal markers in both plexuses as well as in neuronal fibres. Immunohistochemical staining was performed on wholemount preparations of ISP and OSP and on cryostat sections. Antibodies against choline acetyltransferase (ChAT), substance P (SP), somatostatin (SOM), neuropeptide Y (NPY), vasoactive intestinal peptide (VIP), neuronal nitric oxide synthase (nNOS) and the pan-neuronal markers Hu C/D and neuron specific enolase (NSE) were used. The ISP contained 1,380 ± 131 ganglia per cm2 and 122 ± 12 neurons per ganglion. In contrast, the OSP showed a wider meshwork (215 ± 33 ganglia per cm2) and smaller ganglia (57 ± 3 neurons per ganglion). In the ISP, 42% of all neurons expressed ChAT. About 66% of ChAT-positive neurons co-localized SP. A small number of ISP neurons expressed SOM. Chemical coding in the OSP was more complex. Besides the ChAT/±SP subpopulation (32% of all neurons), a nNOS-immunoreactive population (31%) was detected. Most nitrergic neurons were only immunoreactive for nNOS; 10% co-localized with VIP. A small subpopulation of OSP neurons was immunoreactive for ChAT/nNOS/±VIP. All types of neurotransmitters found in the ISP or OSP were also detected in neuronal fibres within the mucosa. We suppose that the cholinergic population in the ISP is involved in the control of epithelial functions. Regarding neurochemical coding, the OSP shares some similarities with the myenteric plexus. Because of its location and neurochemical characteristics, the OSP may be involved in controlling both the mucosa and circular muscle.

Aim: To investigate the roles of toll-like receptor 4 (TLR4) and nuclear factor (NF)-κB on cystathionine β synthetase (CBS) expression and visceral hypersensitivity in rats., Methods: This study used 1-7-wk-old male Sprague-Dawley rats. Western blot analysis was employed to measure the expression of TLR4, NF-κB and the endogenous hydrogen sulfide-producing enzyme CBS in colon dorsal root ganglia (DRG) from control and "irritable bowel syndrome" rats induced by neonatal colonic inflammation (NCI). Colon-specific DRG neurons were labeled with Dil and acutely dissociated to measure excitability with patch-clamp techniques. Immunofluorescence was employed to determine the co-expression of TLR4, NF-κB and CBS in DiI-labeled DRG neurons., Results: NCI significantly upregulated the expression of TLR4 in colon-related DRGs (0.34 ± 0.12 vs 0.72 ± 0.02 for the control and NCI groups, respectively, P < 0.05). Intrathecal administration of the TLR4-selective inhibitor CLI-095 significantly enhanced the colorectal distention threshold of NCI rats. CLI-095 treatment also markedly reversed the hyperexcitability of colon-specific DRG neurons and reduced the expression of CBS (1.7 ± 0.1 vs 1.1 ± 0.04, P < 0.05) and of the NF-κB subunit p65 (0.8 ± 0.1 vs 0.5 ± 0.1, P < 0.05). Furthermore, the NF-κB-selective inhibitor pyrrolidine dithiocarbamate (PDTC) significantly reduced the upregulation of CBS (1.0 ± 0.1 vs 0.6 ± 0.1, P < 0.05) and attenuated visceral hypersensitivity in the NCI rats. In vitro, incubation of cultured DRG neurons with the TLR4 agonist lipopolysaccharide significantly enhanced the expression of p65 (control vs 8 h: 0.9 ± 0.1 vs 1.3 ± 0.1; control vs 12 h: 0.9 ± 0.1 vs 1.3 ± 0.1, P < 0.05; control vs 24 h: 0.9 ± 0.1 vs 1.6 ± 0.1, P < 0.01) and CBS (control vs 12 h: 1.0 ± 0.1 vs 2.2 ± 0.4; control vs 24 h: 1.0 ± 0.1 vs 2.6 ± 0.1, P < 0.05), whereas the inhibition of p65 via pre-incubation with PDTC significantly reversed the upregulation of CBS expression (1.2 ± 0.1 vs 0.6 ± 0.0, P < 0.01)., Conclusion: Our results suggest that the activation of TLR4 by NCI upregulates CBS expression, which is mediated by the NF-κB signaling pathway, thus contributing to visceral hypersensitivity.

Chronic abdominal pain in irritable bowel syndrome (IBS) usually appears in combination with disturbed bowel habits, but the etiological relationship between these symptoms remains unclear. Noradrenaline is a major neurotransmitter controlling pain sensation in the spinal cord. To test the hypothesis that the descending noradrenergic pathway from the brain stem moderates gut motility, we examined effects of intrathecal application of noradrenaline to the spinal defecation center on colorectal motility. Colorectal intraluminal pressure and expelled volume were recorded in vivo in anesthetized rats. Intrathecal application of noradrenaline into the L6-S1 spinal cord, where the lumbosacral defecation center is located, caused propulsive contractions of the colorectum. Inactivation of spinal neurons by tetrodotoxin blocked the effect of noradrenaline. Pharmacological experiments showed that the effect of noradrenaline is mediated primarily by alpha-1 adrenoceptors. The enhancement of colorectal motility by intrathecal noradrenaline was abolished by severing of the pelvic nerves. Our results demonstrate that noradrenaline acting on sacral parasympathetic preganglionic neurons through alpha-1 adrenoceptors causes propulsive motility of the colorectum in rats. Considering that visceral pain activates the descending inhibitory pathways including noradrenergic neurons, our results provide a rational explanation of the concurrent appearance of chronic abdominal pain and colonic motility disorders in IBS patients.

Early-life stress is a determinant of vulnerability to a variety of disorders that include dysfunction of the brain and gut. Here we exploit a model of early-life stress, maternal separation (MS) in mice, to investigate the role of the intestinal microbiota in the development of impaired gut function and altered behaviour later in life. Using germ-free and specific pathogen-free mice, we demonstrate that MS alters the hypothalamic-pituitary-adrenal axis and colonic cholinergic neural regulation in a microbiota-independent fashion. However, microbiota is required for the induction of anxiety-like behaviour and behavioural despair. Colonization of adult germ-free MS and control mice with the same microbiota produces distinct microbial profiles, which are associated with altered behaviour in MS, but not in control mice. These results indicate that MS-induced changes in host physiology lead to intestinal dysbiosis, which is a critical determinant of the abnormal behaviour that characterizes this model of early-life stress.

Background electroacupuncture (EA) at acupoint ST-36 (Zusanli) has been used to alleviate gastrointestinal symptoms and improve gastrointestinal motility, but the effects and mechanisms of EA on enteric nervous system (ENS) have scarcely been investigated. SD rats were randomly divided into eight groups: normal control group, diabetes mellitus group (DM), chronic high-frequency EA (C-HEA), chronic low-frequency EA (C-LEA), chronic sham stimulation group (C-SEA), acute high-frequency EA group (A-HEA), acute low-frequency EA group (A-LEA), and diabetic with acute sham stimulation group (A-SEA). The parameters of HEA included a frequency of 100 Hz and an amplitude of 1 mA, while the parameters for LEA were 10 Hz and 1 mA. The expressions of PGP9.5, neuronal nitric oxide synthase neurons, CHAT neurons, glia cell line-derived neurotrophic factor (GDNF) and p-Akt were measured by immunofluorescence or immunohistochemistry, real-time PCR, and Western blotting methods in colon tissues of each rat. The total neurons and the two types of enteric neurons (neuronal nitric oxide synthase and choline acetyl transferase neurons), together with GDNF and p-Akt in the mRNA and protein level were significantly decreased in DM group compared with the normal control group in colon (P < 0.01). Compared with DM or all other DM with EA groups, the chronic HEA could induce a more significant quantitative increase in the mRNA and protein level of the enteric neurons and GDNF and p-Akt in colon (P < 0.01). EA with high-frequency and long-term stimuli at acupoint ST-36 can induce regeneration of lost enteric neurons in diabetic rats, and GDNF and PI3K/Akt signal pathway may play an important role in EA-induced regeneration of impaired enteric neurons., (Copyright © 2015 the American Physiological Society.)

Quiescent phases of inflammatory bowel disease (IBD) are often accompanied by chronic abdominal pain. Although the transient receptor potential vanilloid 1 (TRPV1) ion channel has been postulated as an important mediator of visceral hypersensitivity, its functional role in postinflammatory pain remains elusive. This study aimed at establishing the role of TRPV1 in the peripheral sensitization underlying chronic visceral pain in the context of colitis. Wild-type and TRPV1-deficient mice were separated into three groups (control, acute colitis, and recovery), and experimental colitis was induced by oral administration of dextran sulfate sodium (DSS). Recovery mice showed increased chemically and mechanically evoked visceral hypersensitivity 5 wk post-DSS discontinuation, at which point inflammation had completely resolved. Significant changes in nonevoked pain-related behaviors could also be observed in these animals, indicative of persistent discomfort. These behavioral changes correlated with elevated colonic levels of substance P (SP) and TRPV1 in recovery mice, thus leading to the hypothesis that SP could sensitize TRPV1 function. In vitro experiments revealed that prolonged exposure to SP could indeed sensitize capsaicin-evoked currents in both cultured neurons and TRPV1-transfected human embryonic kidney (HEK) cells, a mechanism that involved TRPV1 ubiquitination and subsequent accumulation at the plasma membrane. Importantly, although TRPV1-deficient animals experienced similar disease severity and pain as wild-type mice in the acute phase of colitis, TRPV1 deletion prevented the development of postinflammatory visceral hypersensitivity and pain-associated behaviors. Collectively, our results suggest that chronic exposure of colon-innervating primary afferents to SP could sensitize TRPV1 and thus participate in the establishment of persistent abdominal pain following acute inflammation., (Copyright © 2015 the American Physiological Society.)

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., (Copyright © 2015. Published by Elsevier Ireland Ltd.)

The rodent anterior cingulate cortex (ACC) is critical for visceral pain and pain-related aversive response in chronic visceral hypersensitive (VH) state. Long-term potentiation (LTP), induced by theta burst stimulation (TBS) in the medial thalamus (MT)-ACC pathway, is blocked in VH rats. However, the neuronal intrinsic firing characteristics and the MT-ACC connectivity have not been investigated in visceral pain. Using repetitive distension of the colon and rectum (rCRD) as a sensitization paradigm, we have identified that the spontaneous firing rates of ACC neurons and the CRD-stimulated neuronal firings were increased after repetitive visceral noxious stimulation. This correlates with increases in visceral pain responses (visceromotor responses, VMRs). Two multichannel arrays of electrodes were implanted in the MT and ACC. Recordings were performed in free-moving rats before and after repeated CRD treatment. Power spectral density analysis showed that the local field potential (LFP) recorded in the ACC displayed increases in theta band power (4-10 Hz) that were modulated by rCRD. Neural spike activity in the ACC becomes synchronized with ongoing theta oscillations of LFP. Furthermore, cross correlation analysis showed augmented synchronization of thalamo-ACC theta band LFPs, which was consistent with an increase of neuronal communication between the two regions. In conclusion, these results reveal theta oscillations and theta-frequency phase-locking as prominent features of neural activity in the ACC and a candidate neural mechanism underlying acute visceral pain., (Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Background: The aim of the present study was to investigate the effects of the intracolonic transient receptor potential (TRP) A1 agonist allyl isothiocyanate (AITC) on colonic motility and defecation., Methods: The effects of AITC administered into the proximal colonic lumen on colonic motility and defecation were studied in neurally intact dogs equipped with strain-gauge force transducers on the colon, with or without various antagonists. Effects of intracolonic AITC were also studied in dogs with either transection/re-anastomosis (T/R) between the proximal and middle colon and complete extrinsic denervation of an ileocolonic segment., Results: AITC increased colonic motility and induced giant migrating contractions (GMCs) with defecations in 75% of experiments in neurally intact dogs. These effects were inhibited by atropine, hexamethonium, ondansetron, and HC-030031 but unaltered by capsazepine. In dogs with T/R, the increase in colonic motility was inhibited in the middle-distal colon. In dogs with extrinsic denervation, the increase in colonic motility in the distal colon was decreased., Conclusions: Intracolonic AITC stimulates colonic motility and defecation via cholinergic, serotonergic, and TRPA1 pathways. Continuity of colonic enteric neurons plays an essential role in the intracolonic AITC-induced colonic motor response, while extrinsic nerves are important in occurrence and propagation of GMCs.

Aim: To investigate the abundance and potential diagnostic significance of neuroligin-1 and glutamate (Glu) in Hirschsprung's disease (HSCR)., Methods: Ninety children with HSCR and 50 children without HSCR matched for similar nutritional status, age and basal metabolic index were studied. The expression and localization of neuroligin-1 and Glu were assessed using double-labeling immunofluorescence staining of longitudinal muscles with adherent myenteric plexus from the surgically excised colon of children with HSCR. Western blot analysis, quantitative real-time PCR (qRT-PCR) and immunohistochemistry were performed to evaluate the abundance of neuroligin-1 and Glu in different HSCR-affected segments (ganglionic, transitional, and aganglionic segments). Enzyme-linked immunosorbent assay (ELISA) was used to detect and compare serum Glu levels in the long-segment HSCR, short-segment HSCR and non-HSCR samples., Results: Neuroligin-1 and Glu were co-expressed highest to lowest in the ganglionic, transitional and aganglionic segments based on Western blot (neuroligin-1: 0.177 ± 0.008 vs 0.101 ± 0.006, 0.177 ± 0.008 vs 0.035 ± 0.005, and 0.101 ± 0.006 vs 0.035 ± 0.005, P < 0.005; Glu: 0.198 ± 0.006 vs 0.115 ± 0.008, 0.198 ± 0.006 vs 0.040 ± 0.003, and 0.115 ± 0.008 vs 0.040 ± 0.003, P < 0.005) and qRT-PCR (neuroligin-1: 9.58 × 10(-5) ± 9.94 × 10(-6) vs 2.49 × 10(-5) ± 1.38 × 10(-6), 9.58 × 10(-5) ± 9.94 × 10(-6) vs 7.17 × 10(-6 ±) 1.12 × 10(-6), and 2.49 × 10(-5) ± 1.38 × 10(-6) vs 7.17 × 10(-6) ± 1.12 × 10(-6), P < 0.005). Serum Glu level was the highest to lowest in the non-HSCR, short-type HSCR and long-type HSCR samples based on ELISA (in nmol/μL, 0.93 ± 0.31 vs 0.57 ± 0.25, 0.93 ± 0.31 vs 0.23 ± 0.16, and 0.57 ± 0.25 vs 0.23 ± 0.16, P < 0.005)., Conclusion: Neuroligin-1 and Glu may represent new markers of ganglion cells, whose expression may correlate with the pathogenesis, diagnosis, differential diagnosis or classification of HSCR.