Role of VIP and Substance P in NANC Innervation in the Longitudinal Smooth Muscle of the Rat Jejunum-Influence of Extrinsic Denervation

Michael S. Kasparek, Javairiah Fatima, Corey W. Iqbal, Judith A. Duenes, Michael G. Sarr

Research output: Contribution to journalArticle

21 Scopus citations

Abstract

Background: This study was designed to determine changes in nonadrenergic, noncholinergic (NANC) neurotransmission mediated by Vasoactive Intestinal Polypeptide (VIP) and Substance P after small bowel transplantation (SBT). Materials and methods: Six groups of rats (n ≥ 6 per group) were studied: naïve controls (NC); 1 wk after anesthesia/sham celiotomy (SC-1); 1 or 8 wk after jejunal and ileal transection/reanastomosis (TA-1, TA-8), or syngeneic, orthotopic SBT (SBT-1, SBT-8). Jejunal longitudinal muscle strips were studied under NANC-conditions for spontaneous contractile activity, response to exogenous VIP and Substance P, and electrical field stimulation (EFS). Results: Spontaneous activity did not differ between the six groups. VIP inhibited contractile activity in all groups 1 wk postoperatively (P < 0.05), which was prevented by the NO synthase inhibitor L-NG-nitro arginine (L-NNA). In contrast, VIP had no effect in the other groups. Precontraction with Substance P exposed an inhibitory effect of VIP in all groups (P < 0.05 each). Substance P increased contractile activity in all groups, but to a lesser extent in SBT-8 compared with NC, TA-8, and SBT-1 (P < 0.05). The inhibitory effect of EFS at 6 Hz was prevented by L-NNA in NC and TA-8; addition of the VIP antagonist ([D-p-Cl-Phe6, Leu17]-VIP) increased contractile activity in NC, but not in TA-8 and SBT-8. The Substance P antagonist ([D-Pro2, D-Trp7,9]-Substance P) decreased contractile activity during EFS at 50 Hz in NC and SBT-8. Conclusions: SBT decreased response to exogenous Substance P, although release of endogenous Substance P (EFS) is preserved. Changes in VIP signaling are acute and reversible and not caused by effects of SBT.

Original languageEnglish (US)
Pages (from-to)22-30
Number of pages9
JournalJournal of Surgical Research
Volume141
Issue number1
DOIs
StatePublished - Jul 1 2007

Keywords

  • Substance P
  • Vasoactive Intestinal Polypeptide
  • enteric nervous system
  • extrinsic innervation
  • motility
  • nonadrenergic noncholinergic innervation
  • small intestinal transplantation
  • small intestine

ASJC Scopus subject areas

  • Surgery

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