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  • 1
    Electronic Resource
    Electronic Resource
    Neuronal cholecystokinin, gastrin-releasing peptide, neurotensin, and β-endorphin in the intestine of the guinea pig (1984)
    Springer
    Cell & tissue research 235 (1984), S. 521-531 
    Details
    ISSN: 1432-0878
    Keywords: Neuropeptides ; Autonomic nerves ; Smooth muscle ; Gut innervation ; Cholecystokinin octapeptide ; Gastrin-releasing peptide ; Bombesin ; Neurotensin ; β-Endorphin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The guinea-pig intestine was found to harbor nerve fibers containing immunoreactive cholecystokinin (CCK), gastrin-releasing peptide (GRP), neurotensin or β- endorphin. Such fibers occurred in the myenteric and submucous ganglia and in the smooth muscle. GRP- and CCK-fibers, in addition, were found in the mucosa. Following colchicine treatment, neuronal perikarya in the myenteric ganglia displayed CCK-, GRP-, or β-endorphin immunoreactivity. CCK-immunoreactive perikarya were located also in the submucous ganglia. Neurotensin-immunoreactive cell bodies could not be detected. The presence of immunoreactive neuronal perikarya in intramural ganglia indicates that CCK-, GRP- and β-endorphin-containing fibers are intrinsic to the gut wall. GRP, neurotensin, and β-endorphin were identified in extracts of smooth muscle by immunochemical and Chromatographic analysis. CCK-8, GRP and neurotensin contracted the isolated taenia coli. Tetrodotoxin reduced the response to CCK-8 but not that to GRP and neurotensin, suggesting that the two latter peptides act directly on smooth muscle receptors. The effect of CCK-8 is partly mediated by cholinergic nerves, since not only tetrodotoxin but also atropine greatly reduced the CCK-8-induced contractile response. The substance P (SP) antagonist, (d-Pro2, d-Trp7,9)-SP1–11 had no effect on the CCK-8-induced contraction of the taenia. CCK-8 enhanced the SP-mediated (atropine-resistant) contractile response to electrical stimulation but not that mediated by acetylcholine. β-Endorphin had no effect on the tension of the muscle but reduced the response to electrical stimulation (cholinergic as well as SP-mediated) through a naloxone-sensitive mechanism. While CCK-8 and β-endorphin seem to play neuromodulatory roles in the taenia coli, the significance of GRP and neurotensin remains enigmatic.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00226949
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Peptide-containing neurons intrinsic to the gut wall (1981)
    Springer
    Cell & tissue research 214 (1981), S. 225-238 
    Details
    ISSN: 1432-0878
    Keywords: Neuropeptides ; Peptidergic neurons ; Gut innervation ; Intrinsic nerves ; Immunohistochemistry ; Pig
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Nerve fibers containing substance P, VIP, enkephalin or somatostatin are numerous in the porcine gut wall. They are particularly numerous in the submucosal and myenteric plexuses where peptide-containing cell bodies are also observed. Peptide-containing nerve fibers occur also in the vagus nerves, suggesting that the gut receives an extrinsic supply of peptidergic nerves. The extrinsic contribution to the peptide-containing nerve supply of the gut wall has not yet been quantitatively assessed. In an attempt to clarify this question pigs were subjected to bilateral subdiaphragmatic vagotomy. Another group of animals was subjected to complete extrinsic denervation by autotransplantation of a jejunal segment. The pigs were killed at various time intervals after the operations; the longest time interval studied was four months. Following vagotomy the innervation pattern of the jejunum appeared completely unaffected. Following complete extrinsic denervation the adrenergic nerve fibers disappeared, while peptide-containing and acetylcholinesterase-positive nerve fibers remained apparently unaltered. This was confirmed chemically in the case of substance P. The motor activity of smooth muscle from the jejunum was studied in vitro. At low stimulation frequencies the smooth muscle from control jejunum responded by relaxation; upon cessation of stimulation a contraction occurred. With increasing stimulation frequencies the duration of the relaxation decreased; at high frequency stimulation only a contraction was recorded. In the autotransplant low frequency stimulation induced no or only a weak relaxation; high frequency stimulation induced contraction. After cholinergic and adrenergic blockade, the muscle responded with relaxation at all frequencies; the response was similar in innervated and denervated specimens. On the whole, the effects of extrinsic denervation on the motor activity of smooth muscle from porcine jejunum were minor, possibly reflecting the high degree of autonomy of the gut.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00249207
    Library Location Call Number Volume/Issue/Year Availability
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    Paper (German National Licenses)
    Fulltext
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