Differential effects of neurotensin and cholecystokinin on intestinal microcirculation after ischemia-reperfusion

Background. We investigated the effect of neurotensin and cholecystokinin (CCK) on intestinal microcirculation after ischemia-reperfusion. Method: Ischemia was induced in Wistar rats by occlusion of the superior mesenteric artery for 40 min. Ten minutes before reperfusion, infusion of either neurotensin or CCK was started. Afterwards. the microhemodynamics of the jejunum were examined by means of intravital microscopy. Results. Ischemia-reperfusion decreased functional capillary density from 873.4+/-18.1 to 362.5+/-8.3 cm(-1) and red blood cell velocity from 0.49+/-0.03 to 0.34+/-0.02 mm/s. Furthermore, leukocyte-endothelium interaction was increased. Neurotensin infusion significantly increased functional capillary density to 483.2+/-9.0 cm(-1) and red blood cell velocity to 0.69+/-0.01 mm/s in the mucosal capillaries compared with ischemic controls. Despite the amelioration of villus perfusion, the number of nonperfused villi significantly increased (11.8+/-3.6%) compared with ischemic controls. CCK infusion also resulted in a significant increase of functional capillary density (535.2+/-7.4 cm(-1)) and red blood cell velocity (0.67+/-0.01 mm/s). In contrast to neurotensin, the number of non-perfused villi was not increased (5.8+/-2.2%). Conclusion: We conclude that neurotensin further aggravates perfusion inhomogeneity and stasis when administered during the ischemic period. In contrast, CCK has no negative influence on perfusion homogeneity after ischemia-reperfusion. It may be superior to neurotensin in the reconstitution of normal microvascular perfusion patterns after ischemia-reperfusion.