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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
    Anatomy and embryology 140 (1973), S. 109-128 
    ISSN: 1432-0568
    Keywords: Autonomic nervous system ; Gastrointestinal tract ; Adrenergic nerves ; Anal sphincter
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The anatomy and the adrenergic innervation of the rectum, internal anal sphincter and of accessory structures are described for the guinea-pig. The distribution of adrenergic nerves was examined using the fluorescence histochemical technique applied to both sections and whole mount preparations. The longitudinal and circular muscle of the rectum and the muscularis mucosae are all supplied by adrenergic nerve terminals. The density of the adrenergic innervation of the muscularis externa increases towards the anal sphincter. There is a very dense innervation of the internal anal sphincter, of the anal accessory muscles and of the corrugator ani. Non-fluorescent neurons in the ganglia of the myenteric plexus are supplied by adrenergic terminals. The ganglia become smaller and sparser towards the internal anal sphincter and non-ganglionated nerve strands containing adrenergic axons run from the plexus to the sphincter muscle. Adrenergic fibers innervate two interconnected ganglionated plexuses in the submucosa. Very few adrenergic nerve cells were found in the myenteric plexus and they were not found at all in the submucosa. The extrinsic arteries and veins of the pelvic region are heavily innervated by adrenergic nerves. Within the gut wall the arteries are densely innervated but there is little or no innervation of the veins.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1432-0568
    Keywords: Autonomic nervous system ; Adrenergic nerves ; Pelvic viscera ; Gastrointestinal tract
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The adrenergic innervation of the pelvic viscera was examined by the fluorescence histochemical technique, applied to tissue from untreated guinea-pigs and from guinea-pigs in which nerve pathways had been interrupted at operation. It was found that adrenergic neurons in the inferior mesenteric ganglia give rise to axons which run in the colonic nerves and end in the myenteric and submucous plexuses and around the arteries of the distal colon. In the rectum, part of the innervation of the myenteric plexus and all of the innervation of the submucous plexus comes from the inferior mesenteric ganglia. The rest of the adrenergic innervation of the myenteric plexus comes from the posterior pelvic ganglia or the sacral sympathetic chains. The innervation of the blood vessels of the rectum is from the posterior pelvic ganglia. Adrenergic nerves run from the sacral sympathetic chains and pass via nerves accompanying the rectal arteries to the internal anal sphincter. Other adrenergic fibres to the internal anal sphincter either arise in, or pass through, the posterior pelvic plexuses. The anal accessory muscle is innervated by adrenergic axons arising in the posterior pelvic plexuses. Adrenergic nerves which run in the pudendal nerves, probably from the sacral sympathetic chains, innervate the erectile tissue of the penis.
    Type of Medium: Electronic Resource
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  • 4
    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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  • 5
    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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  • 6
    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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  • 7
    ISSN: 1432-0878
    Keywords: NADPH diaphorase ; Immunohistochemistry ; Gastrointestinal tract ; Nitric oxide ; Histochemistry ; Guinea-pig
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The distribution and abundance of nitric oxide synthase (NOS)-containing neurons and their terminals in the gastrointestinal tract of the guinea-pig were examined in detail using NADPH diaphorase histochemistry and NOS immunohistochemistry. NOS-containing cell bodies were found in the myenteric plexus throughout the gastrointestinal tract and in the submucous plexus of the stomach, colon and rectum. NOS-containing neurons comprised between 12% (in the duodenum) and 54% (in the esophagus) of total myenteric neurons. In the ileum, NOS neurons represented 19% of total myenteric neurons. Most of the NOS neurons throughout the gastrointestinal tract possessed lamellar dendrites and a single axon. NOS-containing terminals were abundant in the circular muscle, including that of the sphincters, but were rare in the longitudinal muscle, except for the taeniae of the caecum. The muscularis mucosae of the esophagus, stomach, colon and rectum received a medium to dense innervation by NOS terminals. Within myenteric ganglia, NOS-containing terminals were extremely sparse in the esophagus, stomach and duodenum, common in the ileum and distal colon and extremely dense in the proximal colon and rectum. The submucous plexus in the ileum and large intestine contained a sparse plexus of NOS-containing terminals. NOS terminals were not observed in the mucosa of any region. We conclude that throughout the gastrointestinal tract of the guinea-pig, NOS neurons are inhibitory motor neurons to the circular muscle; in the ileum and large intestine, NOS neurons may also function as interneurons.
    Type of Medium: Electronic Resource
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  • 8
    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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  • 9
    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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  • 10
    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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