Background: Vasoactive intestinal peptide (VIP) is released by stimulation of nonadrenergic noncholinergic (NANC) inhibitory nerves. In order to evaluate the function of VIP in jejunal isografts, we examined the enteric nerve responses in isografted rat jejunum compared with normal jejunum.
Methods: Orthotopic entire small bowel transplantation (SBT) with portocaval drainage was performed from Lewis rats to Lewis rats. Grafted tissue specimens were obtained 130 days after SBT (n = 8). As controls, normal segments of the jejunum were obtained from nontransplanted Lewis rats (n = 20). A mechanograph was used to evaluate in vitro jejunal responses to electrical field stimulation (EFS) of the adrenergic and cholinergic nerves before and after treatment with various autonomic nerve blockers and VIP.
Results: The isografted jejunum was more strongly innervated by excitatory nerves, especially NANC excitatory nerves, than the normal jejunum (P <.05). VIP mediated relaxation reactions of NANC inhibitory nerves in the normal but to a lesser extent in the isografted jejunum (P <.05).
Conclusions: The increased NANC excitatory nerves and the decreased effects of VIP in mediating NANC inhibitory nerves may largely relate to the peristaltic abnormalities seen in the isografted LEW rat jejunum.