Regeneration of Sympathetic Activities in Small Bowel Transplants

Abstract

In order to study the activity of noradrenergic nerve fibres along mesenteric arteries in small-intestinal grafts, the entire jejunoileum was transplanted heterotopically in an isogeneic rat model (group I, n = 12). To assess their influence on graft motility, 9 cm of jejunum were transplanted in an orthotopic position and three bipolar electrodes sutured to the seromuscular layer of the graft (group II, n = 10). Fasting motility was recorded up to postoperative day 42. Animals of group I were sacrificed from day 7 on at weekly intervals and mesenteries were analysed histochemically by fluorescence microscopy. After the 1 st and 2nd week, grafts were found to be completely depleted of noradrenaline. At the end of the 3rd week, fluorescence became detectable along graft mesenteric arteries and showed normal intensity from the end of week 4. Migrating myoelectric complexes (MMCs) were present in all animals of group II. The variability of the MMC period (mean 12.6 min; SD 6.2 min) expressed as variation coefficient (median 36.5; 14.6–74) did not change during the observation period. From these findings it is concluded that there are no extrinsic noradrenergic activities in rat small-intestinal transplants for the first 3 postoperative weeks but they do recover there after. Their influence on graft function remains unclear: MMC periodicity, however, was no influenced.

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

“…This finding is in conflict with other studies, which did not show any sympathetic reinnervation of the bowel wall this early after SBT. Although sympathetic reinnervation occurs along the mesenteric vessels 3 to 4 wk after SBT [33], sympathetic nerve fibers do not appear on the mesenteric side of the transplanted small bowel earlier than 15 wk after SBT [31,34]. One explanation for the TH-positive neurons found in our study is the possible difference in the technique of the transplantation procedure.…”

Long-Term Effects of Extrinsic Denervation on VIP and Substance P Innervation in Circular Muscle of Rat Jejunum

“…Previous studies in the rat have shown that sympathetic reinnervation occurs 3-4 week after SBT, initially along the mesenteric vessels, 40 after 15 week on the mesenteric side of the transplanted small bowel, and by 27 week after SBT to the antimesenteric side. 34,41 Our study supports and extends these findings by exploring the functional effects of reinnervation with an ostensibly normal pattern of TH immunoreactivity on subjective appearance.…”

Effect of chronic, extrinsic denervation on functional NANC innervation with vasoactive intestinal polypeptide and substance P in longitudinal muscle of rat jejunum1

“…A recent study from our laboratory showed a decrease in the sensitivity to exogenous substance P and a decrease of the endogenous release of VIP 8 weeks after SBT in the longitudinal muscle of rat jejunum 15 . The study of long‐term effects of extrinsic denervation, including adaptation and possible reinnervation after SBT, is also of interest in terms of the myoneural function of the transplanted intestine 16–18 …”