Premium
Effects of extrinsic denervation on innervation with VIP and substance P in circular muscle of rat jejunum 1
Author(s) -
Kasparek M. S.,
Fatima J.,
Iqbal C. W.,
Sarr M. G.
Publication year - 2008
Publication title -
neurogastroenterology and motility
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.489
H-Index - 105
eISSN - 1365-2982
pISSN - 1350-1925
DOI - 10.1111/j.1365-2982.2008.01083.x
Subject(s) - vasoactive intestinal peptide , medicine , endocrinology , substance p , jejunum , denervation , stimulation , antagonist , ileum , endogeny , nitric oxide , nitric oxide synthase , chemistry , neuropeptide , receptor
Extrinsic denervation contributes to enteric motor dysfunction after small bowel transplantation (SBT). Our aim was to determine changes in nonadrenergic, noncholinergic innervation with vasoactive intestinal polypeptide (VIP) and substance P (Sub P) in rat jejunal circular muscle after SBT. Muscle strips were studied in tissue chambers from six groups of rats ( n ≥ 6 per group): naïve controls (NC), animals 1 week after anaesthesia/sham celiotomy (SC‐1), and 1 and 8 weeks after jejunal and ileal transection/reanastomosis (TA‐1, TA‐8) and after syngeneic, orthotopic SBT (SBT‐1, SBT‐8). Response to exogenous VIP and Sub P and their endogenous release during electrical field stimulation (EFS) were studied. Exogenous VIP and Sub P caused a dose‐dependent inhibition and stimulation of mechanical activity in all groups respectively ( P < 0.05). The responses to VIP and Sub P were decreased (compared to NC) in all groups at 1 and 8 weeks postoperatively. The VIP antagonist ([ d ‐ p ‐Cl‐Phe 6 ,Leu 17 ]‐VIP) did not prevent the inhibition by exogenous VIP in any group, while the Sub P antagonist ([ d ‐Pro 2 , d ‐Trp 7,9 ]‐Sub P) prevented the effect of exogenous Sub P in NC, TA‐8 and SBT‐8 ( P < 0.05). Responses to exogenous VIP were unaffected by the nitric oxide synthase inhibitor l ‐ N G ‐nitro arginine and precontraction of muscle strips with Sub P. Endogenous release of VIP and Sub P during EFS was preserved after SBT. In circular muscle of rat jejunum, changes in neuromuscular transmission with VIP and Sub P during the first 8 weeks after SBT are not mediated by extrinsic denervation.