Purines and neutrophil leukocytes

1. Adenosine is a normal constituent of all body fluids and its levels are raised, for example, by hypoxia and ischemia. In addition, both adenosine and ATP can be released by endothelial cells and neutrophils in response to physiologic stimulation. 2. Human neutrophil leukocytes possess multiple adenosine receptors and P-2 purinoceptors. 3. ATP can increase intracellular Ca2+ levels in neutrophils, cause degranulation and enzyme release, potentiate the oxidative burst and enhance their adhesion to the endothelium. ATP is broken down to adenosine by ecto enzymes. Via A(1) receptors, adenosine can increase neutrophil chemotaxis and, via A(2A) receptors, it can decrease the oxidative burst, degranulation and adhesion to endothelium. 4. Adenosine and adenine nucleotides are important endogenous modulators of neutrophil functions, and drugs may exert important actions via purinoceptors on neutrophil leukocytes. Copyright (C) 1997 Elsevier Science Inc.