The expression of acetylcholinesterase in proinflammatory cells has supported the hypothesis that this protein plays a role in intercellular adhesion. Previous results of our group show that velnacrine, an acetylcholinesterase inhibitor, increases the number of adherent leukocytes in post-capillary venules of Wistar rats' mesentery muscle. This works intends to evaluate the local application of velnacrine and acetylcholine in the inflammatory response at the microcirculatory network by studying the leukocytes/endothelium interactions in post-capillary venules of Wistar rats' cremaster muscle. The number and the speed of the rolling leukocytes, the number of adherent leukocytes and hemodynamic parameters were determined and also the plasma levels of IL-1beta. The results have shown that in the presence of velnacrine there is a significant increase of the rolling leukocytes (1.28+/-0.39 vs 1.93+/-0.20), as well as an increase of the adherent ones (0.86+/-0.72 vs 1.02+/-0.83). When acetylcholine is adding with velnacrine the number of rolling and adherent leukocytes decreases without changing the IL-1beta plasma circulation induced by velnacrine. Our results suggest an anti-inflammatory role induced by ACh without full efficiency because the rolling leukocytes velocity was reduced without changes in the plasma level of IL-1beta.