Innervation of Syngeneic Vein Grafts in the Rat

Abstract

The regeneration of cholinesterase positive nerves into segments of the supradiaphragmatic inferior vena cava transplanted from one rat into the abdominal aorta of another rat of the same inbred strain and sex were studied, using a histochemical thiocholine method for the demonstration of cholinesterase. Iso-OMPA and BW-284 C 51 were used as inhibitors for nonspecific cholinester-ase (nsChE) and acetylcholinesterase (AChE), respectively. A total of 12 grafts were examined 3, 5, 8, 16, 27 and 32 weeks after transplantation. One single regenerating nsChE reactive nerve was seen near the suture line in a 3-week-old graft. Some solitary regenerating nerves were regularly seen in the grafts at 5 weeks. Eight weeks after grafting some solitary sparsely distributed nerves were found in the outer layers of the graft. In the 16–, 27-, and 32-week-oid grafts, nsChE reactive nerves and small nerve bundles were running either solitary or forming nerve plexa in additon to nerves in the vicinity of vasa vasorum. These regenerated nsChE reactive nerves are probably vasomotor in nature. The AChE reaction showed a clear activity in the intimal layer of the grafted veins. No AChE reactive nerves were seen in the 3-, 5-, and 8-week-old grafts. Only occasional AChE positive nerves were observed 16, 28 and 32 weeks after transplantation. These nerves are probably sympathetic cholinergic nerves.