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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Naunyn-Schmiedeberg's archives of pharmacology 307 (1979), S. 57-63 
    ISSN: 1432-1912
    Keywords: Substance P ; Intestine ; Autonomic nervous system ; Peptidergic nerves
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Acid extracts from both normal and extrinsically denervated ileum contained a compound which was indistinguishable from synthetic substance P; this compound was assayed by examining its contractile effect on the longitudinal muscle of segments of ileum in which receptors for acetylcholine and histamine were blocked. Contractions caused by the compound were markedly and selectively antagonized when the ileum was made insensitive to the action of substance P. The activities in the extract and of synthetic substance P were both destroyed by chymotrypsin but were not affected by trypsin or carboxypeptidase B. The concentrations of substance P-like material in normal and extrinsically denervated segments were not significantly different, being equivalent to 0.48 μg of substance P per g of external muscle plus myenteric plexus. A compound with substance P-like activity was liberated by stimulation of intramural nerves, either electrically or by dimethylphenylpiperazinium, in both normal and extrinsically denervated segments of ileum. The release of this compound was prevented by tetrodotoxin and its action on the muscle was blocked when the ileum was made insensitive to the action of substance P. Experiments with transmural stimulation showed that excitatory nerve pathways involving substance P neurons extend for less than 4 cm along the intestine.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Naunyn-Schmiedeberg's archives of pharmacology 294 (1976), S. 47-60 
    ISSN: 1432-1912
    Keywords: Autonomic pharmacology ; Peristalsis ; Intestine ; 5-hydroxytryptamine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The enteric reflexes in isolated segments of the distal colon and rectum of the guinea-pig were studied by applying localized distensions and recording the consequent changes in circular muscle activity, and by recording tension changes in the circular muscle during the propulsion of a bolus in vitro. Lesions of the wall of the colon were made to locate nerve pathways involved in the reflexes and pharmacological tests were applied to investigate the natures of transmitters released and the types of receptors involved. Distension produced a transient contraction of the circular muscle on the oral side and sustained relaxation on the anal side. Both reflexes were nervemediated. They were elicited in segments deprived of mucosa and submucosa. Interruption of Auerbach's plexus, but not interruption of the submucosal plexus, prevented their conduction. The ascending excitatory reflex was partly blocked by hyoscine and was also partly blocked by methysergide or by making the preparation tachyphylactic to the excitatory action of 5-hydroxytryptamine. The ascending excitatory pathways apparently involve neurons releasing a 5-HT-like transmitter as well as cholinergic neurons. The descending inhibitory reflex was not antagonized by hyoscine, guanethidine, methysergide or mepyramine. It is assumed that the inhibitory neurons activated in this reflex are identical with the noncholinergic, non-adrenergic, enteric inhibitory neurons found throughout the intestine. If both the ascending excitatory and descending inhibitory reflexes acted simultaneously on the same area of circular muscle, the inhibitory response tended to dominate. Pellets of faeces, covered by a thin layer of resin, were introduced into the oral ends of isolated segments of colon. They were propelled analwards at speeds of 0.5–1.6 mm/s. Tension records showed that the pellets were preceded by relaxation and followed by a ring of contraction. The propulsion was blocked by both hyoscine and methysergide. Descending waves of contraction were also observed in empty segments of colon. These occurred spontaneously or were initiated by stretch. They did not occur in the presence of hyoscine or tetrodotoxin. It is postulated that three factors may contribute to propulsion in the guinea-pig distal colon: ascending excitatory reflexes which evoke contractions above a bolus; descending inhibitory reflexes which cause relaxations below; and contractions which, once set up in the circular muscle, travel in an anal direction.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1432-0878
    Keywords: Enteric nervous system ; Intestine ; Neuropeptides ; Gastrin releasing peptide ; Bombesin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Bombesin-like and gastrin-releasing peptide (GRP)-like immunoreactivities were localized in nerves of the guinea-pig small intestine and celiac ganglion with the use of antibodies raised against the synthetic peptides. The anti-bombesin serum (preincubated to avoid cross reactivity with substance P) and the anti-GRP serum revealed the same population of neurons. Preincubation of the antibombesin serum with bombesin abolished the immunoreactivity in nerves while absorption of the anti-GRP serum with either bombesin or the 14–27 C-terminal of GRP only reduced the immunoreactivity. The immunoreactivity was abolished by incubation with GRP 1–27. Immunoreactive nerves were found in the myenteric plexus, circular muscle, submucous plexus and in the celiac ganglion. Faintly reactive nerve cell bodies were found in the myenteric ganglia (3.2% of all neurons) but not in submucous ganglia. After all ascending and descending pathways in the myenteric plexus had been cut, reactive terminals disappeared in the myenteric plexus, circular muscle (including the deep muscular plexus) and the submucous plexus on the anal side. After the mesenteric nerves were cut no changes were observed in the intestinal wall but the reactive fibres in celiac ganglia disappeared. It is deduced that GRP/bombesin-immunoreactive nerve cell bodies in myenteric ganglia project from the myenteric plexus to other myenteric ganglia situated further anally (average length 12 mm), anally to the circular muscle (average length 9 mm), anally to submucous ganglia (average length 13 mm) and external to the intestine to the celiac ganglia. It is concluded that the GRP/bombesin-reactive neurons in the intestinal wall represent a distinct population of enteric neurons likely to be involved in controlling motility and in the coordination of other intestinal functions.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Cell & tissue research 271 (1993), S. 333-339 
    ISSN: 1432-0878
    Keywords: Enteric nervous system ; Prevertebral ganglia ; Retrograde tracing ; Calbindin ; Vasoactive intestinal peptide (VIP) ; Intestine ; Guinea-pig
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Retrograde tracing, using Fast Blue dye, was employed to determine the distribution of enteric nerve cells that project to the superior mesenteric and inferior mesenteric ganglia of the guinea-pig. Retrogradely labelled neurons were found in the myenteric but not submucous ganglia. When the superior mesenteric ganglion was injected, labelled neurons were found in low frequencies (less than 5 nerve cell bodies/cm2) in the duodenum, jejunum, ileum, caecum and proximal colon. The distal colon was analysed in five segments of equal length (1–5; oral to anal). Segment 1 had about 4 labelled nerve cells/cm2, whereas segments 2 to 5 displayed an average of about 25 nerve cells/cm2. The rectum contained about 36 labelled neurons/cm2. After injection of the inferior mesenteric ganglia with Fast Blue, no labelled neurons were found in the duodenum, jejunum, ileum or caecum. No labelled cells were observed in the gallbladder. A small number of labelled cells occurred in the proximal colon and in segment 1 of the distal colon. The frequency of labelled cells increased markedly in the more anal regions of the distal colon, and reached a peak in the rectum (138 cells/cm2). Both nerve lesions and immersion of the cut nerve in Fast Blue solution showed that the superior mesenteric nerve carries the axons of neurons located in the middle distal colon to the superior mesenteric ganglion. Almost half of the neurons in the rectum that project to the inferior mesenteric ganglia do so via the hypogastric nerves. Of neurons that projected to the inferior or superior mesenteric ganglia from the colon or rectum, similar proportions (about 75–80%) showed immunoreactivity for calbindin or VIP. For each of the prevertebral ganglia (coeliac, superior mesenteric and inferior mesenteric) the great majority of peripheral inputs arise from the large intestine.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1432-0878
    Keywords: Enteric nervous system ; Intestine ; Noradrenergic nerves ; Pancreatic polypeptide ; Neuropeptide Y ; Neuropeptides
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Pancreatic polypeptide-like immunoreactivity (PPLI) has been localized in nerves of the guinea-pig stomach and intestine with the use of antibodies raised against avian, bovine and human pancreatic polypeptide (PP), the C-terminal hexapeptide of mammalian PP, and against the related peptide, NPY. Each of the antibodies revealed the same population of neurones. Reactive cell bodies were found in both myenteric (5% of all neurones) and submucous ganglia (26% of all neurones) of the small intestine, and varicose processes were observed in the myenteric plexus, circular muscle, mucosa and around arterioles. The nerves were unaffected by bilateral subdiaphragmatic truncal vagotomy, but the staining of the periarterial nerves disappeared after treatment of animals with reserpine or 6-hydroxydopamine and was also absent after mesenteric nerves had been cut and allowed to degenerate. Vascular nerves showing immunoreactivity for dopamine it-hydroxylase and PPLI had the same distribution. It is concluded that PPLI is located in periarterial noradrenergic nerves. However, other noradrenergic nerves in the intestine do not show PPLI, and PPLI also occurs in nerves that are not noradrenergic. Analysis of changes in the distribution of terminals after microsurgical lesions of pathways in the small intestine showed that processes of myenteric PP-nerve cells provide terminals in the underlying circular muscle and in myenteric ganglia up to about 2 mm more anal. Submucous PP-cell bodies provide terminals to the mucosa.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 1432-0878
    Keywords: Substance P ; Calcitonin gene-related peptide ; Dynorphin ; Cholecystokinin ; Neuropeptide coexistence ; Sensory neurons ; Immunohistochemistry ; Guinea pig
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The co-existence of immunoreactivities to substance P (SP), calcitonin gene-related peptide (CGRP), cholecystokinin (CCK) and dynorphin (DYN) in neurons of the dorsal root ganglion (DRG) of guinea-pigs has been investigated with a double-labelling immunofluorescence procedure. Four main populations of neurons could be identified that contained different combinations of these peptides and had distinctive peripheral projections: (1) Neurons that contained immunoreactivity to SP, CGRP, CCK and DYN were distributed mainly to the skin. (2) Neurons with immunoreactivity to SP, CGPR and CCK, but not DYN, were distributed mainly to the small blood vessels of skeletal muscles. (3) Neurons with immunoreactivity to SP, CGRP and DYN, but not CCK, were distributed mainly to pelvic viscera and airways. (4) Neurons containing immunoreactivity to SP and CGRP, but not CCK and DYN, were distributed mainly to the heart, systemic blood vessels, blood vessels of the abdominal viscera, airways and sympathetic ganglia. Other small populations of DRG neurons containing SP, CGRP or CCK alone also were detected. Perikarya containing these combinations of neuropeptides were not found in autonomic ganglia. The peripheral axons of neurons containing immunoreactivity to at least SP and CGRP were damaged by chronic treatment with capsaicin. However, some sensory neurons containing CCK alone were not affected morphologically by capsaicin. These results clearly show that individual DRG neurons can contain many different neuropeptides. Furthermore, the combination of neuropeptides found in any particular neuron is related to its peripheral projection.
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 1432-0878
    Keywords: Neuropeptides ; Vascular innervation ; Immunohistochemistry ; Small intestine ; Guinea pig
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The neuropeptide content of nerve fibers associated with submucosal arteries in the small intestine of guinea pigs was studied in whole-mount preparations using immunohistochemical methods. Tissues were obtained from normal animals or animals in which the small intestine had been extrinsically denervated. In normal animals, submucosal arteries are innervated by extrinsic sensory nerve fibers which contain both substance P and calcitonin gene-related peptide, and by sympathetic noradrenergic nerve fibers. In preparations obtained from animals 5–9 days after denervation, nerve fibers which contained substance P without detectable calcitonin gene-related peptide were associated with a few submucosal arteries. Nerve fibers which contained vasoactive intestinal peptide were also associated with some arteries. By 42–48 days after extrinsic denervation, substance P-containing fibers (without calcitonin gene-related peptide) and vasoactive intestinal peptide-containing fibers were associated with nearly every blood vessel. The extrinsic sympathetic nerve fibers did not regenerate during the course of this study. The nerve fibers associated with submucosal arteries in denervated tissues were not sensitive to capsaicin treatment. The alteration in the innervation of submucosal arterioles that follows extrinsic denervation of the gut may reflect either an increase in the neuropeptide content of the fibers, synthesis of a new peptide, or an increase in the number of fibers as a result of axonal sprouting.
    Type of Medium: Electronic Resource
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  • 8
    ISSN: 1432-0878
    Keywords: Enteric nervous system ; Intestine, small ; Neurons, types ; Myenteric plexus ; Intracellular dye injection (Lucifer yellow) ; Guinea pig
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The shapes of myenteric neurons in the guineapig small intestine were determined after injecting living neurons with the dye Lucifer yellow via a microelectrode. The cells were fixed and the distribution of Lucifer yellow rendered permanent by an immunohistochemical method. Each of 204 nerve cells was examined in whole-mount preparations of the myenteric plexus and drawn using a camera lucida at 1250 x magnification. Four cell shapes were distinguished: (1) neurons with several long processes corresponding to type II of Dogiel; (2) neurons with a single long process and lamellar dendrites corresponding to type I of Dogiel; (3) neurons with numerous filamentous dendrites; and (4) small neurons with few processes. About 15% of the neurons could not be placed into these classes or into any single class. The type II neurons (39% of the sample) had generally smooth somata and up to 7 (average 3.3) long processes, most of which ran circumferentially. Dogiel type I neurons (34% of sampled neurons) had characteristic lamellar dendrites, i.e., broad dendrites that were flattened in the plane of the plexus. The filamentous neurons (7% of the sample), had, on average, 14 fine processes up to about 50 μm in length. Small neurons with smooth outlines and a few fine processes made up 5% of the neurons encountered. We conclude that myenteric neurons that have been injected with dye can be separated into morphologically distinct classes and that the different morphological classes probably correspond to different functional groupings of neurons.
    Type of Medium: Electronic Resource
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  • 9
    ISSN: 1432-0878
    Keywords: Gastrin ; Gastrin-releasing peptide ; Bombesin ; Stomach ; Autonomic innervation ; Immunohistochemistry ; Guinea pig ; Rat ; Dog ; Man
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The relationship between bombesin-like immunoreactive (bombesin-LI) nerve fibres and gastrin-LI G-cells was examined in gastric antral mucosa from guineapig, rat, dog and man using a double-labelling fluorescence immunohistochemical technique. The greatest density of bombesin-LI nerve fibres was found within the basal mucosa in all species and the density of innervation decreased towards the luminal surface. Most G-cells were in a band occupying approximately the middle third of the mucosa. The proportion of G-cells found within a distance of 2 μm from bombesin-LI nerve fibres was low in all species (6% in the guinea-pig, 22% in the rat, 14% in the dog, and 9% in the human). It is proposed that the neuropeptide released from bombesin-LI antral mucosal nerve fibres traverses distances of greater than several μm to reach the target G-cells. This may be achieved by passage through the mucosal microcirculation.
    Type of Medium: Electronic Resource
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  • 10
    ISSN: 1432-0878
    Keywords: Calcium-binding protein ; Enteric nervous system ; Intestine ; Immunocytochemistry ; Guinea-pig ; Rat ; Man
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Immunoreactivity for vitamin D-dependent calcium-binding protein (CaBP) has been localized in nerve cell bodies and nerve fibres in the gastrointestinal tracts of guinea-pig, rat and man. CaBP immunoreactivity was found in a high proportion of nerve cell bodies of the myenteric plexus, particularly in the small intestine. It was also found in submucous neurons of the small and large intestines. Immunoreactive nerve fibres were numerous in the myenteric ganglia, and were also common in the submucous ganglia and in the intestinal mucosa. Immunoreactive fibres were rare in the circular and longitudinal muscle coats. In the myenteric ganglia of the guinea-pig small intestine the immunoreactivity is restricted to one class of nerve cell bodies, type-II neurons of Dogiel, which display calcium action potentials in their cell bodies. These neurons were also immunoreactive with antibodies to spot 35 protein, a calcium-binding protein from the cerebellum. From the distribution of their terminals and the electrophysiological properties of these neurons it is suggested they might be sensory neurons, or perhaps interneurons. The discovery of CaBP in restricted sub-groups of enteric neurons may provide an important key for the analysis of their functions.
    Type of Medium: Electronic Resource
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