vasoactive-intestinal-peptide and Intestinal-Diseases

Topics: Bile Acids and Salts; Colonic Diseases; Diarrhea, Infantile; Exocrine Pancreatic Insufficiency; Gastrointestinal Neoplasms; Humans; Infant; Infant, Newborn; Intestinal Absorption; Intestinal Diseases; Intestinal Mucosa; Intestinal Secretions; Intestine, Small; Intestines; Protein-Energy Malnutrition; Rotavirus Infections; Vasoactive Intestinal Peptide

Topics: Adenoma, Islet Cell; Diarrhea; Gastrointestinal Hormones; Glucagon; Humans; Intestinal Diseases; Intestinal Neoplasms; Skin; Streptozocin; Syndrome; Vasoactive Intestinal Peptide

Enteric neurons are highly adaptive in their response to various pathological processes including inflammation, so the aim of this study was to describe the chemical coding of neurons in the ileal intramural ganglia in porcine proliferative enteropathy (PPE). Accordingly, juvenile Large White Polish pigs with clinically diagnosed Lawsonia intracellularis infection (PPE; n=3) and a group of uninfected controls (C; n=3) were studied. Ileal tissue from each animal was processed for dual-labelling immunofluorescence using antiserum specific for protein gene product 9.5 (PGP 9.5) in combination with antiserum to one of: vasoactive intestinal polypeptide (VIP), substance P (SP), calcitonin gene-related peptide (CGRP), somatostatin (SOM), neuropeptide Y (NPY) or galanin (GAL). In infected pigs, enteric neurons were found in ganglia located within three intramural plexuses: inner submucosal (ISP), outer submucosal (OSP) and myenteric (MP). Immunofluorescence labelling revealed increases in the number of neurons containing GAL, SOM, VIP and CGRP in pigs with PPE. Neuropeptides may therefore have an important role in the function of porcine enteric local nerve circuits under pathological conditions, when the nervous system is stressed, challenged or afflicted by disease such as PPE. However, further studies are required to determine the exact physiological relevance of the observed adaptive changes.

Topics: Animals; Calcitonin Gene-Related Peptide; Desulfovibrionaceae Infections; Enteric Nervous System; Fluorescent Antibody Technique; Galanin; Ileum; Intestinal Diseases; Neurons; Neuropeptide Y; Somatostatin; Substance P; Swine; Vasoactive Intestinal Peptide

Distension of the small intestine can play a role in the pathogenesis of various functional intestinal disorders. This study determined the role of vasoactive intestinal polypeptide (VIP) in the adaptative response of intestinal smooth muscle to acute and chronic distension of the ileum in vivo. Several in vitro experiments were performed to identify the mechanism of receptor regulation. Distension was applied by a balloon inflated with air in the ileum either during a single episode in anesthetized or repeatedly in conscious guinea pigs. Then, muscle cells were isolated by enzymatic digestion from the distended and nondistended adjacent ileal segments. In addition, in vitro experiments were performed on freshly dispersed cells for determination of mechanisms. Control cells maximally relaxed (Cmax) at 1 microM VIP (EC50 = 50 pM) and 100 microM isoproterenol (EC50 = 7 nM). Both acute and chronic distensions triggered a right-ward shift of the concentration-response curves for VIP (Cmax = 100 microM, EC50 = 10 nM). A desensitization of the relaxing effect of VIP receptors was also observed when cells were preincubated for 30 min in vitro with VIP. By contrast, the relaxing effect of isoproterenol was affected neither by in vivo distension nor by in vitro incubation with isoproterenol. Desensitization of VIP receptors was prevented by in vitro incubation of cells with VIP plus a VIP antagonist [(D-P-Cl-Phe6,Leu17)VIP] and by intraluminal perfusion of the VIP antagonist during acute distention in vivo. Moreover, desensitization of VIP receptors did not occur after 30 min preincubation with either forskolin or 8-Bromo-cyclic AMP. These results indicate that mechanical distension of the ileum induces a homologous desensitization of VIP receptors on circular smooth muscle cells, which requires the occupation of its receptors by VIP.

Topics: 8-Bromo Cyclic Adenosine Monophosphate; Adaptation, Physiological; Animals; Cell Separation; Colforsin; Guinea Pigs; Ileum; In Vitro Techniques; Intestinal Diseases; Isoproterenol; Male; Muscle Contraction; Muscle, Smooth; Receptors, Vasoactive Intestinal Peptide; Sincalide; Stress, Mechanical; Vasoactive Intestinal Peptide

The authors report a case of neuronal intestinal dysplasia in a 6-year-old girl. The disease is characterized by hyperplastic ganglia throughout the large and small intestine, associated with severe constipation. To better understand the pathophysiology of this disease the authors investigated the histopathologic, ultrastructural, and immunohistochemical characteristics of the intestinal tissue in this case. The hyperganglionosis was associated with immunohistochemical findings of intact expression of the neuropeptides controlling the peristaltic reflex, through lower expression of calcitonin-gene related peptide. With the recent progress in our understanding of the neural regulation of gastrointestinal function, it may now be possible to begin to understand the complex pathophysiological mechanisms underlying gastrointestinal motility disorders.

Topics: Calcitonin Gene-Related Peptide; Child; Colon; Constipation; Female; Gastrointestinal Motility; Humans; Hyperplasia; Intestinal Diseases; Myenteric Plexus; Submucous Plexus; Substance P; Vasoactive Intestinal Peptide