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128. Kongress der Deutschen Gesellschaft für Chirurgie

Deutsche Gesellschaft für Chirurgie

03.05. - 06.05.2011, München

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Changes in adrenergic neurotransmission during postoperative ileus in rat

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  • Michael Simon Kasparek - Ludwig-Maximilians Universität München, Chirurgische Klinik und Poliklinik Großhadern, München
  • Brigitte Götz - Walter Brendel Zentrum, Institut für Chirurgische Forschung, München
  • Bernhard Stoklas - Walter Brendel Zentrum, Institut für Chirurgische Forschung, München
  • Mario H. Müller - Chirurgische Klinik und Poliklinik Großhadern, LMU München, München
  • Petra Behnaqi - Walter Brendel Zentrum, Institut für Chirurgische Forschung, München
  • Karl-Walter Jauch - Universitätsklinikum der LMU München-Großhadern, Chirurgische Klinik und Poliklinik, München
  • Martin Ernst Kreis - Chirurgische Klinik und Poliklinik Großhadern, LMU München, München

Deutsche Gesellschaft für Chirurgie. 128. Kongress der Deutschen Gesellschaft für Chirurgie. München, 03.-06.05.2011. Düsseldorf: German Medical Science GMS Publishing House; 2011. Doc11dgch072

doi: 10.3205/11dgch072, urn:nbn:de:0183-11dgch0722

Published: May 20, 2011

© 2011 Kasparek et al.
This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by-nc-nd/3.0/deed.en). You are free: to Share – to copy, distribute and transmit the work, provided the original author and source are credited.

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Introduction: We aimed to investigate the role of α- and β-receptors in control of contractile activity in circular jejunal muscle in rat and to delineate changes in adrenergic neurotransmission during postoperative ileus.

Materials and methods: Muscle strips (n=8/rat) of 6 naive (NC) and 8 Sprague Dawley rats after small bowel manipulation (POI) were studied. Ileus was confirmed by delayed small bowel transit. Dose-response curves were generated for phenylephrine (α-agonist; 10-8-3x10-6M) and isoprenaline (β-agonist; 3x10-10-10-7M) and effects of bethanechol-precontraction (3x10-6M), L-NIL and nimesulide (inhibiting inducible NO-synthase (10-4M) and cyclooxygenase-2 (10-5M)), L-NNA (non-specific NO-synsthase inhibitor; 10-4M), tetrodotoxin (TTX; blocking enteric nervous system; 10-6M), phentolamine (α-antagonist; 10-5M) or propranolol (β-antagonist; 5x10-6M) on response to agonists were studied. Release of excitatory neurotransmitters was investigated by electrical field stimulation (EFS) after inhibiting adrenergic neurotransmission with propranolol and phentolamine without/with atropine (10-7M), L-NIL and nimesulide. Data: mean±SEM.

Results: Small bowel transit was delayed in POI (53±3% vs. 31±4%; p<0.05). Phenylephrine and isoprenaline caused dose-dependent inhibition of spontaneous and stimulated contractile activity (p<0.05). Effect of isoprenaline was increased after TTX, while L-NIL and nimesulide decreased the phenylephrine effect (p<0.05). α- and β-receptor mediated inhibition was more pronounced in NC (p<0.05). This difference was abolished after L-NNA and TTX. L-NIL and nimesulide caused EFS-induced stimulation, which was reduced in POI (53±10 vs. 11±17%; p<0.05). Atropine had no effect on this response in NC while it reduced EFS-induced excitation in POI (46±7 vs. -7±8%; p<0.05).

Conclusion: Contractile activity can be inhibited via muscular α- and β-receptors. The inhibitory potential of isoprenaline is counterbalanced in part by procontractile effects of the enteric nervous system, which are abolished after TTX. Postoperatively α- and β-adrenergic effects are decreased, an effect most likely related to reduced NO-release from the enteric nervous system, as this postoperative change was antagonized by L-NNA and TTX. EFS-induced endogenous release of non-cholinergic, excitatory neurotransmitters from the enteric nervous system is reduced postoperatively. DFG KA2329/5-1.