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PubMed1982

Neurons with 5-hydroxytryptamine-like immunoreactivity in the enteric nervous system: their projections in the guinea-pig small intestine.

Changes in the distribution of 5-hydroxytryptamine-like immunoreactivity have been examined in enteric neurons at various times after microsurgical lesions of the enteric plexuses. In the myenteric plexus, varicose immunoreactive nerve fibres disappeared or were reduced in number in ganglia anal to an interruption of the myenteric plexus. Up to about 2 mm on the anal side, all varicose immunoreactive fibers disappeared from the ganglia. At about 14-16 mm below an interruption, there were about 50% of the normal number of fibres in the myenteric ganglia and at about 24 mm the innervation was normal. In the submucosa, fibres immunoreactive for 5-hydroxytryptamine were absent from an area on the anal side following interruption of the myenteric plexus. From consideration of the pattern of disappearance, it is deduced that some myenteric nerve cell bodies send immunoreactive axons in an anal direction to supply submucous ganglia. The axons run for about 8 mm in the myenteric plexus, enter the submucosa and then run for a further 4 mm approximately. Thus, varicose fibres immunoreactive for 5-hydroxytryptamine, which occur around the enteric ganglion cells of both plexuses arise from nerve cell bodies in myenteric ganglia than send their axons in an anal direction.

Animals↗
PubMed1989

Histological identification of the interstitial cells of Cajal in the guinea-pig small intestine.

In order to clarify the contraversial structure that Cajal (1889, 1893, 1911) called "interstitial cells" in the intestine, we have compared the descriptions by Cajal with our recent findings. Cajal defined three groups of interstitial cells in the intestine: those in the mucosa, the deep muscular plexus, and the myenteric plexus. In the deep muscular plexus, he described cells with small perikarya and long, branching processes. Neither glial cells nor ZIO positive fibroblast-like cells, the only cell types seen in the numbers and location necessary to support Cajal's observations, conformed with the morphology he described. Cajal might have described a composite cell, or chimera, the cell body being that of a glial (or perhaps a fibroblast-like) cell and the processes being simultaneously stained neurites that ran in close association with the cell. In the myenteric plexus, staining with S-100 protein for glial cells and ZIO for fibroblast-like cells reveal cells between the external muscle layers. Cells stained with S-100 protein resemble the drawings and also his description of the interstitial cells, although these cells appear to be less frequent than Cajal's drawings indicate. There are numerous glial cells in the ganglia and primary strands of the plexus which were not included in Cajal's publications. Conversely, the fibroblast-like cells are incidentally associated with nerve fibers. Although they lie in the same plane, the fibroblast-like cells form a pattern distinct from that of the nerve fibers of the tertiary component of the myenteric plexus. These cells occur in the distribution and numbers of the interstitial cells described by Cajal. They are stained by ZIO and also immunoreactive for gamma-aminobutyric acid. They can be identified by scanning electron microscopy. In the mucosa, Golgi staining reveals a pattern of nerve fiber bundles that is indistinguishable from Cajal's drawings. Glial cell bodies frequently occur at the intersections of these bundles and appear as cell nuclei surrounded by a cytoplasm which is actually the stained nerve fiber bundles. What Cajal depicted as interstitial cells were composite structures consisting of glial cells and contiguous nerve fiber bundles. We conclude that the structures which Cajal called interstitial cells in the intestine do not originate from one cell type. Nevertheless, two groups of fibroblast-like cells, those lying parallel and close to the nerve strands of the deep muscular plexus and those of the myenteric plexus, can be recognized by ZIO staining and scanning electron microscopy.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed2006

Distribution of muscarinic receptor subtypes and interstitial cells of Cajal in the gastrointestinal tract of healthy dairy cows.

OBJECTIVE: To describe the distribution of muscarinic receptor subtypes M(1) to M(5) and interstitial cells of Cajal (ICCs) in the gastrointestinal tract of healthy dairy cows. SAMPLE POPULATION: Full-thickness samples were collected from the fundus, corpus, and pyloric part of the abomasum and from the duodenum, ileum, cecum, proximal loop of the ascending colon, and both external loops of the spiral colon of 5 healthy dairy cows after slaughter. PROCEDURES: Samples were fixed in paraformaldehyde and embedded in paraffin. Muscarinic receptor subtypes and ICCs were identified by immunohistochemical analysis. RESULTS: Staining for M(1) receptors was found in the submucosal plexus and myenteric plexus. Antibodies against M(2) receptors stained nuclei of smooth muscle cells only. Evidence of M(3) receptors was found in the lamina propria, in intramuscular neuronal terminals, on intermuscular nerve fibers, and on myocytes of microvessels. There was no staining for M(4) receptors. Staining for M(5) receptors was evident in the myocytes of microvessels and in smooth muscle cells. The ICCs were detected in the myenteric plexus and within smooth muscle layers. Distribution among locations of the bovine gastrointestinal tract did not differ for muscarinic receptor subtypes or ICCs. CONCLUSIONS AND CLINICAL RELEVANCE: The broad distribution of M(1), M(3), M(5), and ICCs in the bovine gastrointestinal tract indicated that these components are likely to play an important role in the regulation of gastrointestinal tract motility in healthy dairy cows. Muscarinic receptors and ICCs may be implicated in the pathogenesis of motility disorders, such as abomasal displacement and cecal dilatation-dislocation.

Animals↗
PubMed2003

Characterization of specific delta-opioid binding sites in the distal small intestine of swine.

Delta-opioid receptors modulate neurogenic smooth muscle contractions and mucosal ion transport in the porcine distal small intestine. We compared specific delta-opioid binding sites in neuronal membranes isolated from the inner submucosal plexus and myenteric plexus of this gut region. In both preparations, the delta-opioid receptor antagonist naltrindole displaced [3H]diprenorphine from two binding sites. [3H]Naltrindole bound specifically to a single high-affinity site that was displaced by delta-opioid receptor ligands with the rank order of affinity: naltriben >7-benzylidenenaltrexone>deltorphin II>[D-Pen(2), D-Pen(5)] enkephalin. Relative decreases in delta-opioid receptor agonist affinity in the presence of Na(+) and other ions differed in submucosal and myenteric membranes. The kappa-opioid receptor antagonist norbinaltorphimine displaced [3H]naltrindole binding in myenteric membranes (K(i)=7.2 nM). Delta-opioid receptors in submucosal and myenteric plexuses of porcine ileum appear to differ in some respects.

Animals↗
PubMedDate not supplied

Sensitization by in vitro incubation with morphine of the myenteric plexus-longitudinal muscle preparation.

1. Myenteric plexus-longitudinal muscle strip preparations from guinea-pig incubated in Krebs solutions at room temperature and bubbled with carbogen gas did not show any functional alteration during 24 h. 2. Moreover, preparations incubated in Krebs solutions did not show any change on the inhibition response produced by liberation of opiaceous material caused by 10 Hz tetanizing stimulation, nor in sensitivity to morphine. 3. When these preparations were incubated in 2.5 X 10(-7) M morphine solutions in Krebs in the same conditions than the preparations incubated without morphine a greater inhibitory response after the 10 Hz tetanizing shock could be seen, as well as a greater sensitivity to morphine, being both phenomena correlatable with the incubation time. Significant statistical differences could be seen for incubation times longer than one hour. From these results we conclude that prolonged in vitro exposition of the myenteric plexus-longitudinal muscle preparation to morphine produced a sensitization of the opiate receptor.

Animals↗
PubMed1990

Calbindin neurons of the guinea-pig small intestine: quantitative analysis of their numbers and projections.

The distribution of nerve cells with immunoreactivity for the calcium-binding protein, calbindin, has been studied in the small intestine of the guinea-pig, and the projections of these neurons have been analysed by tracing their processes and by examining the consequences of nerve lesions. The immunoreactive neurons were numerous in the myenteric ganglia; there were 3500 +/- 100 reactive nerve cells per cm2 of undistended intestine, which is 30% of all nerve cells. In contrast, reactive nerve cells were extremely rare in submucous ganglia. The myenteric nerve cells were oval in outline and gave rise to several long processes; this morphology corresponds to Dogiel's type-II classification. Processes from the cell bodies were traced through the circular muscle in perforating nerve fibre bundles. Other processes ran circumferentially in the myenteric plexus. Removal of the myenteric plexus, allowing time for subsequent fibre degeneration, showed that reactive nerve fibres in the submucous ganglia and mucosa came from the myenteric cell bodies. Operations to sever longitudinal or circumferential pathways in the myenteric plexus indicated that most reactive nerve terminals in myenteric ganglia arise from myenteric cell bodies whose processes run circumferentially for 1.5 mm, on average. It is deduced that the calbindin-reactive neurons are multipolar sensory neurons, with the sensitive processes in the mucosa and with other processes innervating neurons of the myenteric plexus.

Animals↗
PubMed1975

The effects of morphine on the release of noradrenaline from the cat isolated nictitating membrane and the guinea-pig ileum myenteric plexus-longitudinal muscle preparation.

1. Electrical field stimulation of either the cat isolated nictitating membrane or the guinea-pig ileum myenteric plexus-longitudinal muscle preparation caused the release of noradrenaline into the bathing medium. 2. In the cat nictitating membrane, the output per pulse of noradrenaline was constant at frequencies of stimulation from 0.5 to 15 Hz. In the guinea-pig myenteric plexus preparation the output per pulse of noradrenaline increased as the frequency of stimulation was increased from 2 to 16 Hz. 3. Phenoxybenzamine (29.3 muM) caused a marked increase in the noradrenaline output from both the cat nictitating membrane and guinea-pig myenteric plexus preparations. 4. Morphine (0.13-8 muM) inhibited the contractions of the cat nictitating membrane caused by electrical stimulation. This effect was greater at low (1Hz) than at high (15Hz) frequencies of stimulat The site of action is at the nerve-smooth muscle junction. 5. The action of narcotic analgesic drugs on the cat nictitating membrane showed stereospecificity. Naloxone (0.1 muM) reversed the inhibition caused by normorphine (3.2 muM). 6. Morphine (3 muM) reduced the noradrenaline output from the cat nictitating membrane stimulated at 1 Hz but not at 15 Hz. At 1 Hz, the inhibition of noradrenaline output by normorphine (muM) was reversed by naloxone (0.25 muM). 7. Morphine (1.5 muM) did not alter the noradrenaline output from the guinea-pig myenteric plexus preparation stimulated at 2 or 16 Hz.

Animals↗
PubMed1986

Inhibition by indomethacin of naloxone-precipitated opiate withdrawal contraction in isolated guinea pig myenteric plexus-longitudinal muscle preparation.

The isolated myenteric plexus-longitudinal muscle preparation from guinea pigs which had previously been administered morphine chronically 100 mg/kg/day, 7 days) shows a pronounced contraction when exposed to naloxone. Exposure of the preparation to indomethacin (6.7 micrograms/ml) for 10 minutes prior to naloxone inhibits this withdrawal response. A single dose of indomethacin, 1 mg/kg, given on the 6th day on morphine, also inhibits the naloxone contraction. These results suggest the involvement of a prostaglandin in the opiate withdrawal response in the ileum.

Acetylcholine↗
PubMed1995

Co-localization of NADPH diaphorase reactivity and vasoactive intestinal polypeptide in human colon.

Nitric oxide-containing nervous structures were localized in the human colon using NADPH diaphorase activity and nitric oxide synthase immunoreactivity. We found some, solitary NADPH diaphorase-reactive and nitric oxide synthase-immunoreactive neurons in the submucous plexus, while the myenteric plexus contained several neurons, often arranged in clusters, and nerve fibers showing these markers. The circular muscle layer contained a dense plexus of NADPH diaphorase-reactive nerves, which was greater than that in the longitudinal muscle layer. We report on co-localization of NADPH diaphorase activity and VIP immunoreactivity in several neurons of the myenteric ganglia. Such co-localization has not been reported previously for human colon. Localization of nitric oxide synthase and VIP in the myenteric plexus and in the nerves of circular muscle layer raises the possibility that nitric oxide contributes to the regulation of motility in the human colon.

Colectomy↗
PubMed1971

Impulse transmission in the myenteric plexus-longitudinal muscle preparation of the guinea-pig ileum.

1. In a preparation consisting of the myenteric plexus and the longitudinal muscle layer removed from a segment of guinea-pig ileum, spontaneous action potentials occurred which were unaffected by tetrodotoxin but suppressed by Mn(2+) and were therefore myogenic.2. A single current pulse of 0.1 ms duration evoked a response consisting of an early action potential followed after a delay of about 200 ms by a complex of biphasic spikes. The first action potential was conducted for no more than 15 mm and the second complex for 30-70 mm.3. Since the first action potential was unaffected by hyoscine or Mn(2+) but abolished by tetrodotoxin, it was due to excitation of nerve fibres. The later complex of spikes was suppressed by hyoscine and Mn(2+) and therefore due to excitation of smooth muscle. It was also inhibited by adrenaline or morphine, compounds which depress acetylcholine release. The evoked smooth muscle response was followed by absence of spontaneous electrical activity for 2-4 seconds.4. The nerves travelling in a longitudinal direction had a mean maximum conduction velocity of 0.65 m/s, an absolute refractory period of 2.8 ms and a relative refractory period of about 20 ms.5. The conduction velocity of the smooth muscle response evoked by stimulation of the nerve with a single pulse was 0.16 m/second. After a single pulse the muscle was inexcitable for 0.7-1.3 s; the delay of transmission from nerve to muscle was 210 ms. When instead of a single pulse a train of two-five pulses at 20 ms intervals was applied, the size, conduction distance and conduction velocity of the evoked smooth muscle response were increased.

Action Potentials↗
PubMed1983

The effects of erythrosin B(FD & C Red No. 3) on the guinea-pig ileum myenteric plexus-longitudinal muscle preparation.

The responses of the guinea-pig ileum myenteric plexus-longitudinal muscle to the food, drug and cosmetic dye erythrosin B (FD & C Red No. 3) were examined in acetylcholine- and electrically-stimulated preparations. Erythrosin B (10(-6)-10(-4)) reduced the amplitude of the mechanical responses produced by both stimuli. The effects were not simply concentration- and time-dependent. Responses to field stimulation were more sensitive to inhibition by erythrosin B, inhibition increasing with both concentration of dye and time of exposure. Responses to acetylcholine were generally less sensitive to erythrosin B and inhibition at 90 min exposure was more evident at lower concentrations of the dye. Many preparations contracted briefly upon exposure to low concentrations of the dye. Erythrosin B did not significantly affect the specific binding of [3H]QNB to muscarinic receptors. Erythrosin B reduced resting K+ levels in the longitudinal muscle but Na+ concentrations were essentially unaffected. Muscarinic agonist-stimulated uptake of Na+ and release of K+ were inhibited by erythrosin B (10(-6)-10(-4)M); this effect was enhanced with increased time of exposure to the dye. The effects of erythrosin B on cellular ion concentrations were more evident at low than at high concentrations of the dye. Erythrosin B reduced the efflux of [3H]acetylcholine induced by field stimulation from the myenteric plexus longitudinal muscle preparation.

Acetylcholine↗
PubMed2002

Neuronal nitric oxide synthase activity is increased during granulomatous inflammation in the colon and caecum of pigs infected with Schistosoma japonicum.

Neuronal nitric oxide is a non-adrenergic non-cholinergic neurotransmitter in the enteric nervous system and plays a role in a variety of enteropathies including Crohn's and Chagas' diseases, ulcerative colitis, diabetes, atrophy and hypertrophy. The content of neuronal nitric oxide synthase (nNOS) in the colon and the caecum from pigs infected with Schistosoma japonicum was studied using immunohistochemical and histochemical staining for nNOS and nicotinamide adenine dinucleotide phosphate diaphorase (NADPH-diaphorase), respectively. In the infected pigs, lightly, moderately and less severely inflamed tissues showed increased nNOS and NADPH-diaphorase activities in nerve cell bodies and nerve fibres in the enteric plexuses compared to control pigs. There was a significant increase in the nerve cell body density of nNOS immunoreactive nerve cell bodies in the inner submucous plexus, outer submucous plexus and in the myenteric plexus. More intensely stained nerve cell bodies and varicosities were observed in tissue from prenatally infected and prenatally infected, postnatally re-infected pigs compared to postnatally infected pigs. However, the latter showed the highest numerical density of nNOS immunoreactive nerve cell bodies. Marked increases were seen in the inner submucous plexus followed by myenteric plexus, inner circular muscle, outer submucous plexus and mucous plexus. However, in very severe inflamed tissues, the number and staining intensity of nerve cell bodies and nerve fibre varicosities were reduced in plexuses located in the lesions with the inner submucous and mucous plexuses being the most affected. There was no staining in the nervous tissue within the eosinophilic cell abscesses and productive granulomas. The apparent alterations in the activities of enzymes responsible for the generation of nitric oxide (NO) show possible alterations in the NO mediated non-adrenergic non-cholinergic reflexes in the enteric nervous tissue. These alterations might contribute to impaired intestinal motility and absorption, and other pathophysiological conditions seen during S. japonicum infections.

Animals↗
PubMed1984

Fluorescence microscopic study of the architecture and structure of an adrenergic network in the plexus myentericus (Auerbach), plexus submucosus externus (Schabadasch) and plexus submucosus internus (Meissner) of the porcine small intestine.

The distribution of adrenergic fibres in the ganglionated plexuses of the porcine small intestine has been made on air-dried stretch preparations using the glyoxylic acid fluorescence method. Adrenergic fluorescent fibres occur in the ganglia and internodal strands of the three fundamental ganglionated plexuses: the myenteric plexus (Auerbach) and the two superimposed meshworks of the plexus submucosus , i.e. the plexus submucosus externus ( Schabadasch ) and the plexus submucosus internus (Meissner). The plexus Auerbach consists of densely glyoxylic acid induced fluorescent (GIF) elongated ganglia with in general a longitudinal axis running parallel to the circular muscle layer and large dense interconnecting fibre tracts with primary, secondary and tertiary subdivisions. In the ganglia, the fibres are varicose, forming large fluorescent 'baskets' which might be related to the occurrence of well defined enteric neurones. The plexus Schabadasch can be distinguished from the plexus Meissner by its size, strongly fluorescent ganglia and broad densely fluorescent internodal strands. The pattern of fluorescing ring-like formations at the margin and out of the nodes, clearly present in the Auerbach and Schabadasch plexuses, completely lack in the plexus Meissner, the latter being narrow-meshed with smaller fluorescent 'baskets', indicating that the corresponding neurones are smaller in size. In the ganglionic nodes of all three plexuses the axons display comparatively more varicosities than in the fibre tracts. Each of the three main ganglionated enteric plexuses are quite different with regard to the pattern of the adrenergic network both in the ganglia and in the strands.

Animals↗
PubMed2000

Idiopathic myenteric ganglionitis underlying intractable vomiting in a young adult.

Inflammatory infiltration of intestinal myenteric plexuses (i.e. myenteric ganglionitis), along with severe intestinal motor abnormalities, may accompany paraneoplastic syndromes, neurological disorders and gastrointestinal infections, although rare cases can be idiopathic. In this report, we describe the case of a patient who presented with chronic intractable vomiting and weight loss associated with idiopathic myenteric ganglionitis mainly involving the stomach. Tissue analysis showed that the inflammatory infiltrate comprised T lymphocytes (CD4+ and CD8+), and peptide immunolabelling revealed a marked decrease of substance P/tachykinin immunoreactive staining in nerve fibres and myenteric neurones. Following systemic steroid therapy, the patient's symptoms dramatically improved, and after one year of follow-up his general condition remains satisfactory. The possible mechanisms leading to symptom generation and gastric dysmotility in the context of an idiopathic myenteric ganglionitis are discussed.

Adult↗
PubMed1988

There are no morphologic abnormalities of the gastric wall or abdominal vagus in patients with diabetic gastroparesis.

Because there is evidence for vagal autonomic neuropathy as the cause of diabetic gastroparesis, we hypothesized that this disorder should be associated with morphologic abnormalities of the abdominal vagus nerve or gastric myenteric plexus, or both. We studied the smooth muscle and myenteric plexus of the stomach in 18 nondiabetic controls and 16 patients with long-standing diabetes. Five of the diabetics had gastroparesis and 11 did not. We utilized conventional histology and Smith's silver technique for visualizing the myenteric plexus. Neurons within the myenteric plexus were quantified in sections stained with each technique. The abdominal vagus nerves from 5 diabetics (2 with gastroparesis) and 12 nondiabetic controls were stained with hematoxylin and eosin, Gomori trichrome, luxol-fast blue, and Holmes' silver stains. There were no abnormalities in the numbers or appearance of neurons or axons in the myenteric plexus of the stomach of diabetics, with or without gastroparesis. Also absent were abnormalities of the smooth muscle or vagus nerve. Thus, no morphologic abnormalities of the gastric wall or abdominal vagus were identified in diabetic gastroparesis.

Adult↗
PubMed2002

Neurocalcin-alpha immunoreactivity in the enteric nervous system of young and aged rats.

The distribution of the calcium binding protein neurocalcin a has been examined in the enteric nervous system of young adult (3 months) and aged (24+ months) male rats by immunofluorescence. Neurocalcin-immunoreactive (NC-ir) neurons were observed in the submucous and myenteric plexuses throughout the gastrointestinal tract from the oesophagus to the distal large intestine. NC-ir nerve terminals were also seen on NC-ir and NC-negative neurons. Semiquantitative estimates revealed fewer NC-ir neurons in the submucous plexus than in the myenteric plexus. The greatest occurrence of NC-ir neurons was in the small and large intestine. NC-ir axons were seen in the mucosa and also in between the ganglia of the myenteric plexus. In the aged rats, there were no discernible changes in the numbers of NC-ir neurons in th e oesophagus and stomach, with an increase in the pylorus and slight decreases in the small and large intestines. No decrease in NC-ir was observed in the distal large intestine. NC-ir neurons never contained lipofuscin age pigment and many enteric neuro ns devoid of NC-ir contained age pigment. Like other previously investigated calcium-binding proteins in enteric neurons, the distribution of NC shows much variability from one part of the intestine to another. The observed slight decreases in the number of NC-ir enteric neurons in aged rats may compromise the regulation of calcium in these neurons.

Aging↗
PubMed1997

Cellular localization and distribution of the cloned mu and kappa opioid receptors in rat gastrointestinal tract.

Several pharmacological and electrophysiological studies have shown that the opioid receptors are widely distributed in the gastrointestinal tract. Despite such consensus, there are conflicting findings regarding their effects in intestinal function, and their precise site of action remained unclear. The aim of the present study was therefore to delineate the cellular localization of mu and kappa opioid receptors in rat gastrointestinal tract using polyclonal antibodies generated to C-terminal end of the cloned mu (63 amino acids) and kappa (41 amino acids) receptors. The distribution of mu differs from that of kappa receptors within the gastrointestinal wall, with a greater abundance of mu receptor-like immunoreactive fibres in all intestinal layers. Numerous neurons expressing mu receptor-like proteins were found in the submucosal plexus with comparatively few in the myenteric plexus. In contrast, a higher number of neurons expressing kappa receptor-like immunoreactivity were visualized in the myenteric plexus with a small number in the submucosal plexus. A high number of immunopositive neurons were found in the myenteric plexus of the stomach and the proximal colon with both antibodies. In the submucosal and mucosal layers. mu receptor-immunoreactive fibres were more abundant and distributed around the crypts, blood vessels and lymphatic nodes. Interestingly, numerous mu and fewer kappa receptor-immunoreactive interstitial cells are localized in the region of myenteric plexus and at the internal border of the circular muscle. Finally, smooth muscle cells did not demonstrate any mu- nor kappa-receptor immunoreactivity. These findings suggest that in the rat gastrointestinal tract, mu and kappa opioid receptors may directly influence neuronal and interstitial cell activity. This appears not to be the case for the smooth muscle cells. In the muscular layers, the anatomical data point to mu receptor actions being mediated by nerve terminals, whereas kappa receptor effects may be mediated by both nerve terminals and somatodendritic synaptic mechanisms. In contrast, in the submucosal and mucosal layers, mu receptors predominate and are localized on both nerve terminals and somatodendritic synaptic elements.

Animals↗