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  • Intestine, small  (8)
  • Chemistry  (6)
  • Circular muscle  (3)
  • 1
    Electronic Resource
    Electronic Resource
    Inhibitory effects of opioids in a circular muscle-myenteric plexus preparation of guinea-pig ileum (1987)
    Springer
    Naunyn-Schmiedeberg's archives of pharmacology 336 (1987), S. 419-424 
    Details
    ISSN: 1432-1912
    Keywords: Guinea-pig ileum ; Myenteric plexus ; Circular muscle ; Opioid receptors ; Naloxone
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The actions of opioids were examined in a strip preparation of the external muscle and myenteric plexus of the guinea-pig ileum cut parallel to the circular muscle. Contractions of the circular muscle induced by electrical stimulation of myenteric neurons were depressed in a concentration-dependent manner by the mu agonists, morphine and DAGO, and by the kappa agonist, U-50,488H. The concentrations of morphine, DAGO and U-50,488H which depressed nerve-mediated contractions by 50% (IC50) were 86 nM, 11 nM and 5.0 nM, respectively. The equilibrium dissociation constants (K D) for naloxone as an antagonist of the inhibitory effects of DAGO and of U5-0,488H were 5.6 nM and 29.4 nM, respectively. In contrast to the potent inhibitory effects of mu and kappa agonists, the delta-selective agonist, d-Pen-l-Pen, produced only weak inhibition of nerve-mediated contractions. Even at a concentration of 3 μM, there was less than 50% inhibition, which was not antagonised by the delta receptor antagonist, ICI 174864. The experiments indicate that both mu and kappa opioid receptors are present on the myenteric neurons supplying the circular muscle and that delta receptors are either absent or ineffectively activated.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00164876
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  • 2
    Electronic Resource
    Electronic Resource
    Opioid dependence in myenteric neurons innervating the circular muscle of guinea-pig ileum (1989)
    Springer
    Naunyn-Schmiedeberg's archives of pharmacology 339 (1989), S. 166-172 
    Details
    ISSN: 1432-1912
    Keywords: Guinea-pig ileum ; Myenteric plexus ; Circular muscle ; Opioid dependence ; Morphine withdrawal
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Guinea-pigs were treated with morphine for 6–8 days by subcutaneous implantation of pellets, each containing a mixture of morphine base (120 mg) and morphine hydrochloride (35 mg). Each guinea-pig received a single pellet. Mechanical activity of the circular muscle was recorded in vitro in preparations comprising the circular muscle and myenteric plexus. Exposure to morphine was maintained by addition of 1 μM morphine to the organ baths. After 90 min, morphine was withdrawn, either by repeatedly washing tissues in morphine-free Krebs' solution , or by addition of naloxone to reduce the occupancy of the opioid receptors by morphine. Withdrawal of morphine resulted in markedly enhanced contractile activity compared with that in circular muscle-myenteric plexus preparations from untreated control guinea-pigs. The withdrawal contractions were abolished by tetrodotoxin (600 nM) and greatly reduced by hyoscine (1 μM), indicating that they resulted from action potential discharge in myenteric neurons that release acetylcholine onto the circular muscle. Activation of the cholinergic excitatory motor neurons was not secondary to synaptic activation by cholinergic interneurons, because hexamethonium (100 μM) did not affect withdrawal contractions. The withdrawal response may therefore arise in the cholinergic excitatory motor neurons themselves, or in neurons that activate them via noncholinergic mechanisms.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00165139
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  • 3
    Electronic Resource
    Electronic Resource
    Opioid mu and kappa receptors on axons of cholinergic excitatory motor neurons supplying the circular muscle of guinea-pig ileum (1988)
    Springer
    Naunyn-Schmiedeberg's archives of pharmacology 338 (1988), S. 397-400 
    Details
    ISSN: 1432-1912
    Keywords: Guinea-pig ileum ; Circular muscle ; Opioid receptors
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary In preparations of guinea-pig ileum comprising the circular muscle and the axonal processes of myenteric neurons, electrical stimulation evoked contractions of the circular muscle which were abolished by tetrodotoxin and by hyoscine, indicating that they resulted from action potential-mediated release of acetylcholine. The selective mu opioid agonist, (d-Ala2-N-Me-Phe4-Gly5-ol)-enkephalin (DAGO), and the selective kappa opioid agonist, trans-(±)-3,4-dichloro-N-(2-(I-pyrrolidinyl) cyclohexyl) benzeneacetamide, U-50488H, caused concentration-dependent and naloxone-reversible inhibitions of nerve-mediated contractions. The experiments indicate that opioid mu and kappa receptors are present on the axonal processes of cholinergic excitatory motor neurons supplying the circular muscle of the guinea-pig ileum.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00172116
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  • 4
    Electronic Resource
    Electronic Resource
    The projections of chemically identified nerve fibres in canine ileum (1987)
    Springer
    Cell & tissue research 247 (1987), S. 377-384 
    Details
    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
    URL: http://dx.doi.org/10.1007/BF00218319
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  • 5
    Electronic Resource
    Electronic Resource
    Osmocentrifugation in density gradients: Application to polymer latex separation (1987)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 34 (1987), S. 853-861 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Polymer latexes can be fractionated by size and by chemical composition through osmocentrifugation. Density gradients are formed by centrifuging Ficoll and Percoll solutions in dialysis cells; mixed polymer latex zones are layered over these gradients and centrifuged again, leading to separated latex bands from which polymer may be collected and further analyzed. Zone migration rates in the osmocentrifugation experiment are faster than in standard centrifugation tubes.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1987.070340234
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  • 6
    Electronic Resource
    Electronic Resource
    Use of 2-deoxyglucose in the selective isolation of mutants of trichoderma reesei with enhanced β-glucosidase production (1980)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 22 (1980), S. 2429-2432 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260221121
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  • 7
    Electronic Resource
    Electronic Resource
    The use of the inverted linear model of enzyme decay to plan a strategy for enzymatic batch reactions and to assess the industrial applicability of immobilized enzyme preparations (1983)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 25 (1983), S. 745-759 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: This article is concerned with the development of a model to plan a strategy for an enzymatic batch process where enzyme is subjected to deactivation described by the inverted linear decay model. The particular system studied is the enzymatic hydrolysis of penicillin to 6-amino penicillanic acid (6 APA), but the model can be utilized with other batch systems as long as the decay of the immobilized enzyme (IME) preparation is described by the inverted linear decay model. The model developed is eminently practical and simple and several example of its application are shown. Experimental data obtained in a small pilot plant batch recirculated reactor on the average are well fitted by this model. For IME systems whose decay is best described by the first-order decay model, it is not possible to use the same approach.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260250311
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  • 8
    Electronic Resource
    Electronic Resource
    Galanin-immunoreactive neurons in the guinea-pig small intestine: their projections and relationships to other enteric neurons (1987)
    Springer
    Cell & tissue research 250 (1987), S. 607-615 
    Details
    ISSN: 1432-0878
    Keywords: Galanin ; Enteric nervous system ; Intestine, small ; Neuropeptides ; Guinea-pig
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Galanin immunoreactivity was observed in nerve cell bodies and nerve fibres, but not in enteroendocrine cells, in the small intestine of the guinea-pig. Nerve terminals were found in the myenteric plexus, in the circular muscle, in submucous ganglia, around submucous arterioles, and in the mucosa. Lesion studies showed that all terminals were intrinsic to the intestine; those in myenteric ganglia arose from cell bodies in more orally placed ganglia. Myenteric nerve cells were also the source of terminals in the circular muscle. Galanin (GAL) was located in a population of submucous nerve cell bodies that also showed immunoreactivity for vasoactive intestinal peptide (VIP) and in a separate population that was immunoreactive for neuropeptide Y (NPY). Processes of the GAL/VIP neurons supplied submucous arterioles and the mucosal epithelium. Processes of GAL/NPY neurons ran to the mucosa. It is concluded that galanin immunoreactivity occurs in several functionally distinct classes of enteric neurons, amongst which are neurons controlling (i) motility, (ii) intestinal blood flow, and (iii) mucosal water and electrolyte transport.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00218954
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  • 9
    Electronic Resource
    Electronic Resource
    Projections and pathways of submucous neurons to the mucosa of the guinea-pig small intestine (1992)
    Springer
    Cell & tissue research 269 (1992), S. 87-98 
    Details
    ISSN: 1432-0878
    Keywords: Submucous plexus ; Mucosa ; Muscularis mucosae ; Intestine, small ; Retrograde transport ; Dil ; Guinea-pig
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Double-labelling immunohistochemistry and retrograde transport of the carbocyanine dye, DiI, were used to establish the pathways of submucous neurons to the mucosa of the guinea-pig small intestine. Following the application of DiI to a villus, DiI-labelled nerve cell bodies were found in the submucous plexus up to 8.3 mm circumferentially and 3.8 mm longitudinally. The size of each of the four characterised classes of submucous neurons was determined and their distributions and projections mapped. Cells characterised by vasoactive intestinal polypeptide immunoreactivity accounted for 52% of DiI-labelled cells and had the longest projections. Cells characterised by neuropeptide Y (19%) or by calretinin immunoreactivity (13% of all DiI-labelled neurons) had relatively short projections and cells with substance P immunoreactivity (20%) had intermediate lengths of projection. When DiI was applied directly to the submucous plexus, filled neurons of all classes had significantly shorter projections, indicating that they must run for considerable distances in other pathways to the mucosa, probably via the non-ganglionated plexus. On average, each villus is innervated by at least 70 submucous neurons. From quantitative estimates there are 9 submucous neurons per villus. Thus, each submucous neuron is likely to supply about 8 villi. This demonstrates a high degree of convergence and divergence in the innervation of the mucosa.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00384729
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  • 10
    Electronic Resource
    Electronic Resource
    The source of the nerve fibres forming the deep muscular and circular muscle plexuses in the small intestine of the guinea-pig (1987)
    Springer
    Cell & tissue research 247 (1987), S. 497-504 
    Details
    ISSN: 1432-0878
    Keywords: Enteric nervous system ; Intestine, small ; Nerves, degeneration ; Neuronal connections ; Guinea-pig
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary A quantitative ultrastructural study was made of the neuntes forming the deep muscular and circular muscle plexuses of the guinea-pig small intestine following microsurgical lesions designed to interrupt intrinsic and extrinsic nerve pathways within the intestinal wall. Removal of a collar of longitudinal muscle with attached myenteric plexus from the circumference of a segment of small intestine resulted in the subsequent disappearance of 99.3% of neurites in the underlying circular muscle. The few surviving neurites in the deep muscular plexus and circular muscle disappeared completely from lesioned segments that were, in addition, extrinsically denervated surgically. These results indicate that the majority of nerve fibres in the deep muscular and circular muscle plexuses of the guinea-pig small intestine is intrinsic to the intestine and originates from nerve cell bodies located in the overlying myenteric plexus. At the light-microscopic level, nerve bundles were traced from the myenteric plexus to the circular muscle.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00215742
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