Differential adrenergic response to extrinsic denervation in canine longitudinal jejunal and ileal smooth muscle.
Early postoperative complications after small bowel transplantation (SBT) are likely mediated, at least in part, by dysmotility caused by the obligate disruption of extrinsic and enteric nerves in the graft. Adrenergic hypersensitivity of gut smooth muscle has been observed in some (but not all) segments of intestine in various experimental models of SBT, highlighting regional and species variability in response to denervation. Little is known about changes in canine longitudinal muscle after extrinsic denervation. Six dogs each underwent either complete extrinsic denervation of the jejunoileum or a control operation (transection and reanastomosis of the proximal jejunum and distal ileum). In vitro contractile response of longitudinal muscle strips to norepinephrine was evaluated at the time of the operation, and 2 weeks and 8 weeks later. After extrinsic denervation, the jejunal response to norepinephrine was preserved at all time points; however, the ileum displayed a decreased sensitivity to norepinephrine, an effect unmasked after intramural neural blockade with tetrodotoxin. These data support a potential for neurally mediated dysmotility after SBT and reinforce the differences in responses to extrinsic denervation between species, as well as differences within different regions and between anatomic segments of small intestine in the same species.
Zyromski
Nicholas J
NJ
Gastroenterology Research Unit and Department of Surgery, Mayo Clinic, Rochester, MN 55905, USA.
Duenes
Judy A
JA
Kendrick
Michael L
ML
Libsch
Karen D
KD
Seiler
Roland
R
Tanaka
Toshiyuki
T
Sarr
Michael G
MG
D000320:Adrenergic Fibers / Q000502:physiology*; D000818:Animals; D003714:Denervation; D004285:Dogs; D005260:Female; D007082:Ileum / Q000502:physiology; D066298:In Vitro Techniques; D007421:Intestine, Small / Q000637:transplantation*; D007583:Jejunum / Q000502:physiology; D023421:Models, Animal; D009119:Muscle Contraction / Q000502:physiology*; D009130:Muscle, Smooth / Q000502:physiology*; D011897:Random Allocation; D012778:Short Bowel Syndrome / Q000601:surgery