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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Naunyn-Schmiedeberg's archives of pharmacology 333 (1986), S. 393-399 
    ISSN: 1432-1912
    Keywords: Enteric neurons ; Mucosal transport ; Noradrenaline ; Somatostatin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Noradrenaline (NA) and somatostatin (SOM) stimulate intestinal water and ion absorption and are found in mucosal nerve fibres and nerve terminals in submucous ganglia of the guinea-pig small intestine. As the main projection of submucous neurons is to the mucosa, NA and SOM might alter mucosal transport either by a direct effect on the epithelium or indirectly, by affecting submucous neurons. In this study these two possible sites of action of NA and SOM have been investigated in mucosa-submucosa preparations of guinea-pig ileum. In addition, the actions of NA and SOM on the secretory responses caused by stimulation of different populations of submucous neurons have been studied. The stimulants of secretion used were a nicotinic agonist, 1,1-dimethyl-4-phenylpiperazinium (DMPP, 10−5 M), 5-hydroxytryptamine (5-HT, 10−7 M) and electrical field stimulation (EFS), which activate cholinergic, noncholinergic and mixed populations of submucous secretomotor neurons, respectively. Segments of intestine were dissected free of external muscle and myenteric plexus and mounted in Ussing chambers. Short-circuit current (I sc) was measured as an indication of net active ion transport across the tissue. NA (≥10−8 M) and SOM (〉10−10 M) each caused a decrease in I sc, indicating a net increase in ion absorption. The NA response was abolished and the magnitude of the SOM response was reduced to 20% by tetrodotoxin (10−7 M). DMPP, 5-HT and EFS each stimulated nerves that increased I sc and each of these responses was significantly diminished by NA and SOM; for both NA and SOM the decrease in the DMPP response was significantly greater than the decrease observed in the response to carbachol (10−6 M). Phentolamine (10−6 M) abolished all of the effects of NA but caused no change in the SOM effects. These studies have shown that NA and SOM cause similar changes in net ion transport, that their actions are primarily on submucous secretomotor neurons and that NA and SOM can diminish the responses to stimulation of both cholinergic and noncholinergic submucous neurons. In this tissue it is also known that SOM coexists with NA in noradrenergic nerve terminals in the submucosa. However, when applied together, NA and SOM caused no greater decrement in the carbachol and 5-HT responses than would be predicted by adding the separate effects of NA and SOM. Hence there was no obvious interaction between NA and SOM effects on mucosal transport.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Cell & tissue research 113 (1971), S. 67-82 
    ISSN: 1432-0878
    Keywords: Gastrointestinal tract ; Vascular innervation ; Adrenergic nerves ; Fluorescence histochemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The fluorescence histochemical method has been used to investigate the adrenergic innervation of the vessels of the gastrointestinal tract. Both stretch preparations and sections of blood vessels taken from cats, guinea-pigs, rabbits and rats were examined. A dense innervation of the major mesenteric arteries and their branches was found. Most of the nerve fibres are at the adventitio-medial border, but a few fibres penetrate the mediae of some large arteries. The innervation of the arterial branches in the gut wall is also dense, particularly in the submucosa. Generally, adrenergic nerves do not accompany capillaries. Arterio-venous shunts are apparently without any specialised adrenergic innervation. The veins of the gut wall are very sparsely supplied by adrenergic nerves but, except in the cat, as the veins increase in size towards the hepatic portal vein their density of innervation also increases. The hepatic portal vein is heavily innervated, most of the nerves being at the outer limit of the circular muscle. The innervation of the vessels of the gastrointestinal tract is correlated with their responses to the stimulation of sympathetic nerves.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Cell & tissue research 120 (1971), S. 364-385 
    ISSN: 1432-0878
    Keywords: Gastrointestinal tract ; Adrenergic neurones ; Adrenergic mechanisms ; Fluorescence histochemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In the present work, the effects of drugs on the storage, uptake and synthesis of catecholamines in intrinsic and extrinsic adrenergic neurones of the guinea-pig intestine are compared, using the fluorescence histochemical technique for localising catecholamines. In respect to the properties examined in this work, the intrinsic adrenergic neurones of the proximal colon of the guinea-pig were found to be qualitatively similar to adrenergic neurones of the sympathetic chains: the intrinsic cells and their terminals are depleted by reserpine or guanethidine; they concentrate and retain catecholamines and this uptake is blocked by desmethylimipramine or phenoxybenzamine; after depletion by reserpine, the fluorescence can be restored by the dopamine and noradrenaline precursor, dopa and this restoration is prevented by blocking the decarboxylation of dopa to dopamine. However, there are clear quantitative differences: the terminals of intrinsic neurones are less susceptible than are extrinsic neurones to depletion by reserpine, guanethidine or 6-hydroxydopamine; the intrinsic neurones more readily retain noradrenaline after reserpinisation. It is suggested that quantitative differences between extrinsic and intrinsic neurones of the intestine could involve a difference in the activity of monoamine oxidase.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Cell & tissue research 120 (1971), S. 346-363 
    ISSN: 1432-0878
    Keywords: Gastrointestinal tract ; Adrenergic nerves ; Enteric ganglia ; Sympathetic denervation ; Fluorescence histochemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The fluorescence histochemical method has been used to examine the adrenergic innervation of the proximal colon of the guinea-pig. Previous investigations have shown that the adrenergic fibres of the gastrointestinal tract arise from extrinsic ganglia. However, in this work it is shown that adrenergic nerve cells are found in the myenteric plexus of the proximal colon and that these cells provide varicose terminals about ganglion cells in the nodes of the plexus. About 75% of the nodes of the myenteric plexus in the proximal colon contain adrenergic cells. A few cells are also observed along the internodal strands. The cells have a cytoplasmic fluorescence, which is of different intensity in different cells, but there is no fluorescence of the nucleus. Processes can be traced from most cells and in some cases these are seen to become varicose. Interruption of extrinsic nerve pathways to the intestine causes a disappearance of the fluorescence reaction of the adrenergic terminals in the ileum, most of the distal colon and in the submucosal and perivascular plexuses of the proximal colon. In contrast, about 60% of the adrenergic terminals in the myenteric plexus of the proximal colon survive extrinsic denervation. From cell counts, it is estimated there are about 10000 adrenergic cells in the proximal colon.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Cell & tissue research 108 (1970), S. 150-176 
    ISSN: 1432-0878
    Keywords: Cardio-vascular innervation ; Reptilia ; Adrenergic nerves ; Fluorescence histochemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The fluorescence histochemical method has been used to study the adrenergic innervation of the cardio-vascular system of the lizard, Trachysaurus rugosus. The cardiac muscle of the caval veins, sinus venosus, auricle and of the papillary muscle of the ventricle is heavily innervated. Some areas of the ventricles are uninnervated. The aortic arches and the elastic arteries are all adrenergically innervated. These arteries have nerve fibres in their mediae and innervated vasa vasorum at the medio-adventitial border. Adrenergic nerves usually do not penetrate the media of muscular arteries. The pattern of innervation of the peripheral arteries is similar to that of mammals, the principal exception being the pulmonary artery which is extremely densely innervated. All the major veins are innervated, but the innervation is generally far sparser than that of the arteries. Many of the small veins have little or no adrenergic innervation. The patterns of innervation seen in stretched, air dried preparations and in sections are described and possible functional implications are discussed.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 1432-0878
    Keywords: Key words Enteric nervous system ; Somatostatin ; Immunocytochemistry ; Intestinal motility ; Synaptic connections ; Guinea-pig
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract  Somatostatin immunoreactivity occurs in a specific subgroup of cholinergic descending interneurons in the myenteric plexus of the guinea-pig small intestine. In the present work, we made light- and electron-microscopic investigations of chemically defined inputs to these neurons, in order that the origins of the connections of other neurons with them could be deduced. Somatostatin-immunoreactive synapses and close contacts were found on the cell bodies and filamentous processes of somatostatin neurons; these were 84% of all inputs. It is thus confirmed that this class of interneuron forms chains that project anally. Descending interneurons with immunoreactivity for nitric oxide synthase provided 14% of inputs to somatostatin-immunoreactive descending interneurons. An antiserum against a calcium-binding protein, calbindin, was used as marker for the majority of intrinsic primary afferent neurons, AH/Dogiel type II neurons; this class of neurons provided only 2.5% of the inputs to somatostatin-immunoreactive descending interneurons. We conclude that somatostatin-immunoreactive descending interneurons are involved in the conduction of impulses distally along the full length of the small intestine, but receive only a minor input from calbindin-immunoreactive primary afferent neurons.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Cell & tissue research 237 (1984), S. 299-308 
    ISSN: 1432-0878
    Keywords: Somatostatin ; Somatostatin immunoreactivity ; Somatostatin-containing neurons ; Stomach ; Intestine small ; Intestine, large ; Man
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Somatostatin-immunoreactive nerves and endocrine cells were localized by use of immunohistochemistry in human stomach, small and large intestine. The nature of the immunoreactivity in acid extracts of separated layers of intestine was determined with separation by high pressure liquid chromatography followed by detection with radioimmunoassay; authentic somatostatin-14 was found in the external musculature, which contains nerves, and in the submucosa and mucosa, which contain both nerve fibres and endocrine cells. The distribution of somatostatin nerves in the gastric antrum, duodenum, jejunum, ileum, ascending and sigmoid colon, and rectum is described. In the intestine many positive perikarya and fine varicose fibres were seen. Mucosal fibres formed a sub-epithelial plexus and a looser network in the lamina propria; this nerve supply was less dense in the large intestine. Submucous ganglia contained positive perikarya and terminals; many terminals formed pericellular baskets, mainly around non-reactive cells. A small number of nerve fibres were associated with submucosal blood vessels. The innervation of the circular and longitudinal muscle was sparse. Positive nerve terminals were seen in the myenteric plexus, although fewer than in the submucous ganglia; positive perikarya were scarce in myenteric ganglia. Somatostatin-immunoreactive nerves were found in the muscle layers and myenteric plexus of the gastric antrum, but were not detected in the antral mucosa and all layers of the gastric body. The distribution of human enteric somatostatin nerves is compared to that in small laboratory animals, and possible roles for these nerves are discussed.
    Type of Medium: Electronic Resource
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  • 8
    ISSN: 1432-0878
    Keywords: Choline acetyltransferase ; Cholecystokinin ; Neuropeptide Y ; Somatostatin ; Substance P ; Intestine, small ; Submucous ganglia ; Guinea-pig
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The peptides cholecystokinin (CCK), neuropeptide Y (NPY), somatostatin (SOM), substance P (SP) and vasoactive intestinal peptide (VIP), and the synthesizing enzyme for acetylcholine, choline acetyltransferase (ChAT) were localized immunohistochemically in nerve cell bodies of the submucous ganglia in the small intestine of the guinea-pig. VIP-like immunoreactivity was found in 45% of submucous neurons. ChAT immunoreactivity was observed in a separate group of nerve cells, which made up 54% of the total population. There were three subsets of neurons immunoreactive for ChAT: (1) ChAT neurons that also contained immunoreactivity for each of the peptides CCK, SOM and NPY, representing 29% of all submucous neurons; (2) ChAT neurons that also contained SP-like immunoreactivity, representing 11% of all submucous neurons, and (3) ChAT cells that did not contain any detectable amount of the peptides that were localized in this study.
    Type of Medium: Electronic Resource
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  • 9
    ISSN: 1432-0878
    Keywords: Calcitonin gene-related peptide ; Cholecystokinin ; Choline acetyltransferase ; Neuropeptide Y ; Somatostatin ; Enteric nervous system ; Intestine, small ; Guinea-pig
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Antisera to neuropeptide Y (NPY) gave an intense immunohistochemical reaction of certain nerve cells in the myenteric and submucous plexuses of the guinea-pig small intestine. Each nerve cell had up to 20 branching, tapering processes that were less than ∼50 μm long and a long process that could be followed for a considerable distance. This morphology corresponds to that of the type-III cells of Dogiel. The long process of each myenteric cell ran through the circular muscle to the submucosa, and in most cases the process could be traced to the mucosa. The submucous nerve cell bodies also had processes that extended to the mucosa. These cell bodies, in both plexuses, also stained with antisera raised against calcitonin generelated peptide (CGRP), cholecystokinin (CCK), choline acetyltransferase (ChAT) and somatostatin (SOM), but did not stain with antibodies against enkephalin, substance P or vasoactive intestinal peptide. Thus, it has been possible for the first time to trace the processes of chemically specified neurons through the layers of the intestinal wall and to show by a direct method that CGRP/CCK/ChAT/NPY/ SOM myenteric and submucous nerves cells provide terminals in the mucosa.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Springer
    Cell & tissue research 247 (1987), S. 377-384 
    ISSN: 1432-0878
    Keywords: Enkephalin ; Gastrin releasing peptide ; Neuropeptide Y ; Somatostatin ; Substance P ; Vasoactive intestinal peptide ; Enteric nervous system ; Intestine, small ; Dog
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The projections of nerve fibres with immunoreactivity for the peptides enkephalin (ENK), gastrin-releasing peptide (GRP), neuropeptide Y (NPY), somatostatin (SOM), substance P (SP) and vasoactive intestinal peptide (VIP) were studied in canine small intestine by analysing the consequences of lesions of intrinsic and extrinsic nerves. Of peptides present in fibres supplying myenteric ganglia, GRP, SOM and VIP were in anally directed nerve pathways, whereas ENK and NPY were in orally directed pathways. Pathways ran for up to about 30 mm. SP fibres ran for short distances in both directions in the myenteric plexus. The circular muscle was supplied with ENK, NPY, SP and VIP fibres arising from the myenteric ganglia, whereas most mucosal SP and VIP fibres were deduced to arise from submucous ganglia. There were projections of fibres reactive for ENK, GRP, SOM, SP and VIP from myenteric ganglia to submucous ganglia. Antibodies to tyrosine hydroxylase were used to locate noradrenaline nerve fibres supplying the intestine; these fibres all disappeared when extrinsic nerves running through the mesentery to the small intestine were cut. It is deduced that there is an ordered pattern of projections of peptide-containing fibres in the canine intestine.
    Type of Medium: Electronic Resource
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