Browsing by Subject "Enteric nervous system"
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- PublicationOpen AccessDifferential roles of serotonin receptor subtypes in regulation of neurotrophin receptor expression and intestinal hypernociception(Universidad de Murcia, Departamento de Biologia Celular e Histiologia, 2024) She, Meng-Ping; Hsieh, Yu-Ting; Lin, Li-Yu; Tu, Chia-Hung; Wu, Ming-Shiang; Hsin, Ling-Wei; Yu, Linda Chia HuiObjectives. Aberrant serotonin (5-hydroxytryptamine, 5-HT) metabolism and neurite outgrowth were associated with abdominal pain in irritable bowel syndrome (IBS). We previously demonstrated that 5-HT receptor subtype 7 (5-HT7) was involved in visceral hypersensitivity of IBS-like mouse models. The aim was to compare the analgesic effects of a novel 5-HT7 antagonist to reference standards in mouse models and investigate the mechanisms of 5-HT7-dependent neuroplasticity. Methods. Two mouse models, including Giardia post-infection combined with water avoidance stress (GW) and post-resolution of trinitrobenzene sulfonic acid-induced colitis (PT) were used. Mice were orally administered CYY1005 (CYY, a novel 5-HT7 antagonist), alosetron (ALN, a 5-HT3 antagonist), and loperamide (LPM, an opioid receptor agonist) prior to measurement of visceromotor responses (VMR). Levels of nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), and neurotrophin receptors (NTRs) were assessed. Results. Peroral CYY was more potent than ALN or LPM in reducing VMR values in GW and PT mice. Increased mucosal 5-HT7-expressing nerve fibers were associated with elevated Gap43 levels in the mouse colon. We observed higher colonic Ntrk2 and Ngfr expression in GW mice, and increased Bdnf expression in PT mice compared with control mice. Human SH-SY5Y cells stimulated with mouse colonic supernatant or exogenous serotonin exhibited longer nerve fibers, which CYY dose-dependently inhibited. Serotonin increased Ntrk1 and Ngfr expression via 5-HT7 but not 5-HT3 or 5-HT4, while Ntrk2 upregulation was dependent on all three 5-HT receptor subtypes. Conclusions. Stronger analgesic effects by peroral CYY were observed compared with reference standards in two IBS-like mouse models. The 5-HT7-dependent NTR upregulation and neurite elongation may be involved in intestinal hypernociception
- PublicationOpen AccessHirschsprung’s disease as a model of complex genetic etiology(F. Hernández y Juan F. Madrid. Universidad de Murcia. Departamento de Biología Celular e Histología, 2013) Borrego, Salud; Ruiz-Ferrer, Macarena; Fernández, Raquel M.; Antiñolo, GuillermoHirschsprung disease (HSCR), or aganglionic megacolon, is a developmental disorder characterised by the absence of ganglion cells along variable length of the distal gastrointestinal tract, leading to the most common form of functional intestinal obstruction in neonates and children. Aganglionosis is attributed to a failure of neural crest cells to migrate, proliferate, differentiate or survive during enteric nervous system (ENS) development in the embryonic stage. The incidence of HSCR is estimated at 1/5000 live births and most commonly presents sporadically with reduced penetrance and male predominance, although it can be familial and may be inherited as autosomal dominant or autosomal recessive. In 70% of cases, HSCR occurs as an isolated trait and in the other 30% HSCR is associated with other congenital malformation syndromes. HSCR has a complex genetic etiology with several genes and loci being described as associated with either isolated or syndromic forms. These genes encode for receptors, ligands (especially those participating in the RET and EDNRB signaling transduction pathways), transcriptional factors or other cell elements that are usually involved in the neural crest cell development and migration that give rise to ENS. Nevertheless, the RET proto-oncogene is considered the major disease causing gene in HSCR. A common RET variant within the conserved transcriptional enhancer sequence in intron 1 has been shown to be associated with a great proportion of sporadic cases and could act as a modifier by modulating the penetrance of mutations in other genes and possibly of those mutations in the RET proto-oncogene itself.
- PublicationOpen AccessInvestigation of general and cytoskeletal markers to estimate numbers and proportions of neurons in the human intestine(Murcia : F. Hernández, 2006) Ganns, D.; Schrödl, F.; Neuhuber, W.; Brehmer, A.An important requirement in pathological diagnostics in the human enteric nervous system (ENS) is the estimation of the total numbers of neurons and of proportions of distinct subpopulations. In this study, we compared the suitability of two suggested panneuronal markers, cuprolinic blue (CB) and anti-Hu-protein (HU), for staining and counting human myenteric neurons in wholemounts, derived from small and large intestinal samples. Furthermore, the proportional expression of three cytoskeletal intermediate filaments, a-internexin (IN), neurofilament 200 (NF) and peripherin (PE), was correlated with both CB and HU. In 8 CB- and HUstained wholemounts, 93.3% of all neurons were double labeled, 3.3% of neurons were stained only with CB whereas 3.3% were immuno-stained only for HU. Thus, both markers were comparably reliable in representing the putative total human myenteric neuron population in our material. The wholemounts double stained for IN/CB or IN/HU revealed between 56.2 and 71.5% of neurons to be IN-reactive. Between 42.8 and 50.9% of neurons were immunoreactive for NF whereas 53.9 to 62.4% of neurons were reactive for PE. Although our sample number was too small to allow final conclusions, we suggest that the variations in proportions of intermediate filament expression we observed may be due to individual circumstances rather than to correlation with age or region. The proportions of neurons positive for IN, NF or PE but unstained by CB histochemical or HU immunohistochemical techniques was between 0 and 2.2%. We conclude that both CB and HU techniques are suitable methods for representation of almost all myenteric neurons in the human gut and that the differential expression of the cytoskeletal proteins investigated has to be included in the classification of enteric neurons in pathological diagnostics of human gastrointestinal diseases.
- PublicationOpen AccessMyenteric plexus in the gastrointestinal tract of non-obese diabetic mice(Murcia : F. Hernández, 1998) Spangeus, A.; El-Salhy, M.The myenteric plexus was investigated in the gastrointestinal tract of pre-diabetic and diabetic nonobese diabetic (NOD) mice. The plexus was immunostained by the avidin-biotin complex method, using a general marker for nerve elements, namely protein geneproduct 9.5. The nerve fibres were quantified by pointcounting and the number of ganglia and their area were determined by image analysis. The relative volume density of the nerve fibres in duodenal muscularis propria was found to be significantly reduced in of both pre-diabetic and diabetic NOD mice. There was no statistical difference between controls and NOD mice regarding relative volume density of nerve fibres in antral and colonic muscularis propria. The number of myenteric ganglialmm baseline was significantly decreased in the duodenum of diabetic NOD mice, and showed a non-statistically significant tendency to decrease in pre-diabetic mice. In the antrum and colon, there was no difference between the controls and NOD mice regarding the number of ganglialmm baseline. Nor was there any significant difference between controls and NOD mice in the area of myenteric ganglia in either antrum, duodenum or colon. It is concluded that the changes in the duodenal myenteric plexus of NOD mice are prior to the onset of diabetes. It is suggested that the absence of changes in the antral and colonic myenteric plexus when using a general marker for neuroelements does not preclude a possible change in cholinergic, adrenergic or peptidergic innervation.
- PublicationOpen AccessOccurrence of two NOS isoforms in the developing gut of sea bass Dicentrarchus labrax (L.)(Murcia : F. Hernández, 2007) Pederzoli, A.; Conte, A.; Tagliazucchi, D.; Gambarelli, A.; Mola, L.In this work we have examined the appearance and distribution of nitric oxide synthase (NOS), with histochemical, immunohistochemical and biochemical methods, during development of the sea bass (Dicentrarchus labrax) gut. The data showed that both the calcium-calmodulin dependent neuronal isoform (nNOS) and calciumindependent inducible isoform (iNOS) are present in the larval gut of sea bass. The nNOS-immunoreactivity was present in the epithelial cells and enteric nerve cells of gut both in the 8-day-old specimens and in the 24-dayold- larvae. In the adult nNOS-immunoreactivity disappeared from epithelial cells, remaining in the wall intramural neurons and fibers. The iNOSimmunoreactivity was present in the epithelial cells of 24-day-old-larvae and was not detectable in the adult gut. Western blot analysis and determination of NOS activity also demonstrated the presence of the two NOS isoforms, nNOS and iNOS, in the gut of 24-day-old specimens. The presumably different roles played by the two isoforms of enzyme are discussed. The presence of nNOS isoform in the gut enteric neurons of the same larval stages of D. labrax in which we previously demonstrated the presence of substance P and Vasoactive Intestinal Polypeptide (VIP), may suggest that all these three components of the motility control system are already present in the larval phase. Nitric oxide (NO) may be also involved in the early immune response. The present results on the occurrence of iNOS isoform in epithelial gut cells of the same regions in which the gut-associated lymphoid tissue (GALT) will differentiate, may suggest for NO a role in early defence mechanisms, before the establishment of immune responses in GALT. Finally, the developmental and regional differences in nNOS and iNOS expession also suggest a regulatory role in development and differentiation of the sea bass gut.
- PublicationOpen AccessStructural organization of enteric(Murcia : F. Hernández, 1995) Ibba-Manneschi, L.; Martini, M.; Zecchi-Orlandini, S.; Faussone-Pellegrini, M.SThe organization of the Enteric Nervous System (ENS) was studied in the human colon. Fragments of the whole colonic wall were either routinely processed or Zinc-Iodide Osmium impregnated. Single-layer preparations were also obtained from some of the Zinc-Iodide Osmium-impregnated specimens. The results showed some differences in the organization of human colonic ENS from that of other mammals. In fact, the human submucous plexus was made up of three interconnected ganglionated networks arranged along three different planes. With respect to the myenteric plexus, its ganglia were large sized and irregularly shaped. Moreover, during the microdissection of the colonic wall, we found the absence of a cleavage plane between the circular and longitudinal muscle layers; on the other hand the cleavage plane between mucosa and submucosa was not immediately below the muscularis mucosae, but slightly deeper, since the innermost part of the submucosa remained adhering to overlying layers.