Peripheral and central actions of orphanin FQ (nociceptin) on murine colon.

Orphanin FQ (OFQ), also known as nociceptin, is a recently isolated endogenous peptide with a structure similar to the endogenous opioid peptides. The present study examines the actions of centrally administered OFQ on in vivo murine gastrointestinal and colonic transit as well as the actions of OFQ on the isolated colon. Intracerebroventricular injections of OFQ dose dependently inhibited colonic propulsive activity. OFQ inhibition of colonic propulsion was unaffected by coadministration of the competitive opioid receptor antagonist naltrexone. A subadditive response was observed when approximately equipotent doses of either morphine sulfate or the delta-agonist DPDPE were coadministered with OFQ. No subadditivity was observed with coadministration of the micro-agonist DAMGO, suggesting a functional interaction between OFQ and delta-opioid central pathways regulating colonic transit. High, but not low, doses of OFQ also inhibited the transit of a nonabsorbable charcoal marker through the stomach and/or small intestine. OFQ potently contracted isolated colon preparations; contractile activity was abolished by TTX or chlorpromazine. Our results suggest that OFQ may be an important peptide ligand acting on a novel inhibitory neural pathway that modulates gastrointestinal transit.

Evaluation of early events in the creation of amyenteric opossum model of achalasia.

Benzyldimethyltetradecylammonium chloride (BAC) has previously been used to create amyenteric rat jejunal models. Fifteen opossums (D. virginiana) were injected with 10-15 mL 4 mM BAC or saline in the distal oesophagus and along with controls underwent oesophagoscopy, manometry and barium oesophagrams. Atropine and sodium nitroprusside were studied in six of the BAC-treated and five controls using oesophageal manometry. Histologically several neuronal markers, B-NADPH-diaphorase and acetylcholine esterase histochemical staining were used. NADPH-diaphorase activity was assayed at the lower oesophageal sphincter (LOS) and 3 and 5 cm above LOS in both groups. Oesophagoscopy of the treated animals showed no mucosal inflammation, or strictures. Manometrically, LOS pressures were significantly higher in the BAC-treated group (25.7 +/- 8.6 mmHg) when compared to controls (8.7 +/- 1.8 mmHg). The oesophageal contraction amplitudes were similar in both groups. While sodium nitroprusside (SNP) significantly reduced the LOS pressure, atropine did not alter the resting LOS pressure in the BAC-treated animals. Histologically at the LOS the treated group showed: (i) absence of myenteric neurons, in contrast to prominent NADPH-diaphorase and other neuron and peptide markers in the control and (ii) increase in the number of nerve bundles that were not positive for AchE. No differences were seen in the oesophageal body between the groups. The NADPH-diaphorase assay showed a significant decrease of activity in the BAC-treated LOS, but no differences in the oesophageal body compared to controls. Several of these radiologic, manometric and histological observations resemble features of achalasia and the mechanism of the tonic pressure increase at this early time point appears to be due to a non-cholinergic mechanism.

Neuropeptide Y- and peptide YY-containing colonic cells increase with ageing in male rats.

Colonic mucosal cells are known to contain several neuropeptides. The distribution of various peptide-containing cells in the colon and their possible modulation by aging and diet are unknown. We quantitated various peptide-containing cells from male Lobund-Wistar rat colon at 2, 22, 28, 30 and 33 months of age using indirect immunohistochemical techniques for several peptides including: neuropeptide Y, peptide YY, somatostatin, and chromogranin A. Four diets, varying in total calories and fat content, were examined. Serum gastrin was quantified by RIA at 2 and 33 months. Only NPY-, PYY- and SOM-positive cells were found in the colon. The number per crypt of neuropeptide Y-positive (0.55 +/- 0.04 at 2 months vs 0.80 +/- 0.22 at 33 months, P = 0.015) and peptide YY-positive cells increased with age. Staining for somatostatin and chromogranin, a marker for all enterochromaffin (EC) cells, revealed no change with aging. Diet did not influence the numbers of any peptide-containing cell. Serum gastrin was not different between the groups. A specific increase in NPY- and PYY-positive cells occurs in the aged rat colon. The extent to which this change may be related to age-related colonic dysmotility seen in elderly humans is worthy of exploration.

Immunohistochemical evaluations of ultrashort-segment Hirschsprung's disease. Report of three cases.

PURPOSE: Unlike classic Hirschsprung's disease, short-segment and ultrashort-segment varieties are usually found to be latent and milder. Ultrashort-segment Hirschsprung's disease may present as intractable chronic constipation in children over one year of age, adolescents, and adults. Anorectal myectomy has been shown in many instances to provide effective long-term treatment for certain patients with ultrashort-segment Hirschsprung's disease. Histologically, the affected segment in Hirschsprung's disease has been shown to have increased cholinergic nerves, lack of nitric oxide synthase-containing neuronal elements, and show moderate to severe loss of myenteric neurons. METHODS: Here, we report three cases that showed clinical and manometric evidence of ultrashort-segment Hirschsprung's disease. Two of the three patients responded well to myectomy. RESULTS: Detailed histologic and immunohistochemical evaluation of the internal anal sphincter and a comparison with three normal controls revealed absence of nitric oxide synthase-containing neurons in both cases that responded well to surgery and continued presence of these neurons in the patient who did not respond. A review of the current literature on various treatment modalities is included. CONCLUSIONS: Anorectal myectomy provides long-term relief of this chronic problem in a subgroup of patients with ultrashort-segment Hirschsprung's disease who lack nitrinergic neurons at the internal anal sphincter.

Dopaminergic defect of enteric nervous system in Parkinson's disease patients with chronic constipation.

Clinical studies suggest that gut disorders are common in Parkinson's disease, but the morphological basis is unknown. Depletion of dopamine-containing neurons in the central nervous system is a basic defect in Parkinson's disease. We compared colonic tissue from 11 patients with advanced Parkinson's disease, 17 with adenocarcinoma (normal tissue was studied), and five who underwent colectomy for severe constipation. Immunohistochemistry was used to stain myenteric and submucosal neurons for dopamine, tyrosine hydroxylase, and vasoactive intestinal polypeptide (VIP). Each class of neurons was quantified as a percentage of the total neuronal population stained for the marker protein gene product 9.5. Nine of the 11 Parkinson's disease patients had substantially fewer dopaminergic myenteric neurons than the other subjects (mean 0.4 [SE 0.2] vs 6.9 [2.3] in controls and 5.7 [2.0] in constipated subjects). There was very little difference between the groups in numbers of tyrosine-hydroxylase and VIP neurons. Two Parkinson's disease patients had similar distributions of all types of neurons, including dopaminergic myenteric neurons, to the controls. High-performance liquid chromatography showed lower levels of dopamine in the muscularis externa (but not mucosa) in four Parkinson's disease patients than in four controls (7.3 [5.1] vs 24.2 [4.6] nmol per g protein), but levels of dopamine metabolites were similar in the two groups. The identification of this defect of dopaminergic neurons in the enteric nervous system in Parkinson's disease may lead to better treatment of colorectal dysfunction in this disease.

Electrophysiological and pharmacological responses of chronically denervated lower esophageal sphincter of the opossum.

BACKGROUND & AIMS: Achalasia is characterized by loss of myenteric neurons and incomplete relaxation of the lower esophageal sphincter (LES). The aim of this study was to develop an achalasia model in the opossum using the surfactant benzyldimethyltetradecylammonium chloride (BAC). This study further characterizes the achalasia model. METHODS: BAC or saline was injected circumferentially into the LES of 14 adult opossums. Eight months after injection, manometry, isolated muscle bath studies, electrical field stimulation, and histochemical analysis were performed. RESULTS: Manometrically, the LES of BAC-treated opossums showed higher pressures (38.7 +/- 12 mm Hg vs. 17 +/- 3.0 mm Hg) and reduced esophageal body contraction amplitudes (4.2 +/- 3 mm Hg vs. 27.4 +/- 12 mm Hg). Isolated muscle strips challenged with carbachol and sodium nitroprusside contracted and relaxed similarly to controls. Electrical field stimulation failed to induce relaxation in BAC-treated tissue but did induce contraction. Contractile responses were markedly reduced by tetrodotoxin and atropine in BAC-treated animals and controls. An altered nitric oxide system was shown by the lack of response to L-arginine and N omega-nitro-L-arginine. Histology showed loss of myenteric neurons and increased cholinergic nerve bundles. CONCLUSIONS: Loss of NO inhibitory myenteric neurons markedly reduces the relaxation of the LES, and histology and pharmacological responses suggest a proliferation of cholinergic nerves into the LES contributing to the static elevated pressures of the amyenteric LES.

A severe case of diversion colitis with large ulcerations.

Diversion colitis is an inflammatory condition that develops in the excluded segment of colon after surgical diversion. Inflammatory changes include aphthous-type ulcerations, crypt abscesses, and mucosal friability. These features may be seen in other inflammatory diseases of the colon, making diagnosis difficult. Even though symptoms such as cramping pain, bleeding, and mucous discharge have been described with diversion colitis, most cases are asymptomatic. In this article we report a patient who presented with sepsis secondary to severe diversion colitis with several large (2-4 cm in diameter), deep ulcerations and air in the colonic wall, requiring colectomy.

Peptidergic and nitrinergic denervation in congenital esophageal stenosis.

Congenital esophageal stenosis (CES) is a rare disorder with narrowed esophageal lumen that presents as dysphagia from childhood and that is often associated with tracheobronchial remnants or webs. The pathogenesis of CES is unknown. The aim of this study was to examine the histological and immunohistochemical features of CES. Esophagi from 2 young adults with CES and 3 controls with no motility disorders underwent routine H&E staining, trichrome staining for collagen, and detailed immunocytochemical studies for general neuronal markers (protein gene product 9.5, neuron-specific enolase, and S-100) and neurotransmitters (vasoactive intestinal polypeptide, substance P, and galanin) and nitric oxide synthase by beta-nicotinamide adenine dinucleotide phosphate (NADPH)-diaphorase and a specific NO synthase antibody. Quantitative experiments compared the numbers of myenteric neurons and amounts of fibers at the circular muscle. CES esophagi showed infiltration of neutrophils in the myenteric plane, without any increase in collagen. NADPH-diaphorase histochemistry showed a significant reduction of myenteric nitrinergic neurons (7 +/- 3.4 vs. 2.7 +/- 1.8 neurons per high-power field) and fibers at the circular muscle. Other peptidergic neurons studied were not significantly reduced in CES. The specific total lack of NO inhibitory innervation may be an important mechanism in the pathogenesis of stenosis and aperistalsis of the esophagus in this disorder.