ABSTRACT
AKIRA NISHIYAMA* and YOUICHI ABE Department of Pharmacology, Kagawa Medical University, 1750-1 Ikenobe, Miki-cho, Kita-gun, Kagawa 761-0793, Japan
Abstract-Adenosine exerts membrane receptor-mediated effects on renal hemodynamics and function. Endogenously produced adenosine is proposed to be formed primarily by renal tubular epithelial cells and approaches the vascular smooth cells of the renal vasculature from the extracellular space, i.e. the interstitium. Hence, it is important to determine the dynamics of adenosine levels in renal interstitial fluid. Indeed, many studies have indicated that the effects of adenosine on renal hemodynamics depend on its concentration in the interstitium. Furthermore, in vitro studies reveal that adenosine in the renal interstitial fluid binds to membrane receptors from the adventitial side and initiates renal microvascular responses. Recently, we developed a renal microdialysis method to monitor the concentration of adenosine in renal interstitial fluid. This method is well suited for in vivo studies investigating alterations in renal interstitial adenosine levels. In this review, we summarize the literature pertaining to alterations in renal interstitial fluid concentrations of adenosine in some pathophysiological conditions. Potential roles of interstitial adenosine for regulating renal hemodynamics were also discussed.
