Background: Adrenaline tolerance improves survival in animal models of shock. The purpose of the present study was to determine the effects of adrenaline tolerance on intestinal ischemia-reperfusion (IIR) in a rat model. 
Materials and Methods: Adrenaline tolerance was developed by injecting adrenaline intravenously (IV), gradually 
increasing the dose from 0.05 mg/kg to 2 mg/Kg at 5 days. In experimental animals, the intestine was subjected to ischemia for one hour and then reperfusion for 3 hours. Evans blue was given IV to all animals to quantify pulmonary microvascular injury. After reperfusion, animals were sacrificed and the effects of reperfusion were assessed by measuring tissue myeloperoxidase (MPO), malonyldialdehyde (MDA), liver neutrophil sequestration and serum alanine aminotransferase (ALT). Intestinal injury was also assessed by a histological mucosal injury score. 
Results: Evans blue dye concentrations were significantly higher in animals with IIR than in those having sham IIR or 
in AT-rats having IIR or sham IIR (P<0.01). MPO levels were significantly lowered in the lung by adrenaline tolerance 
(P<0.05). MDA levels significantly increased in the lung, liver and intestine of the IIR group compared with those in the sham IIR groups (P< 0.01), whereas there was no difference in adrenaline-tolerant animals. Adrenaline tolerance significantly reduced PMN sequestration within the liver and serum ALT levels as compared to the IIR group (P<0.05), which were significantly higher than the sham IIR group. The intestinal mucosal injury scores increased significantly in IIR animals as compared with sham IIR animals (P<0.01). Adrenaline tolerance did not reduce this injury. 
Conclusions: The present study indicates that IIR leads to local and remote organ dysfunction, catecholamines are 
involved in the IIR insult, and induction of adrenaline tolerance has a possible protective effect, though the local injury 
appears to be independent of catecholamines.