[Changes in vasoactive intestinal polypeptide levels in intestinal obstruction and the influence of da cheng qi decoction].

The role of vasoactive intestinal polypeptide (VIP) in small intestine obstructed rabbits and the therapeutic mechanism of Da Cheng Qi Decoction (DCQD) were studied. VIP concentrations of both blood and intestinal tissue were measured by specific radio-immunoassay in a rabbits' mechanical small intestinal obstruction model using fix of ileum to the right low abdominal wall, the influences of duodenal perfusion of DCQD on VIP levels were also investigated. 24 hours after ligating ileum, VIP of arterial plasma was elevated 7 fold, reaching 138.65 +/- 25.58 pmol/L, that of portal vein plasma was 4 times of the arterial value. VIP immunoactivity was detected in peritoneal fluid. VIP content of duodenal tissue in 16 intestine obstructed rabbits was 2 times high as that in 15 controls, whereas that of colonal tissue was inversed. DCQD caused a 50% decrease of elevated plasma VIP in experimental animals and a 65% increase in controls. The present work demonstrates that VIP might be released into the portal and peripheral circulation and mediate local and systemic pathophysiologic alterations accompanying small intestinal obstruction, such as hyperemia and edema of intestinal wall, accumulation of fluid in the lumen. VIP changes might account for the redistribution of blood flow in the obstructed segment of small intestine and the distal site of obstruction. DCQD has a therapeutic effect. The mechanism of dual modulate action of DCQD on VIP concentration is beyond our knowledge.