We investigated possible renal protective and therapeutic effects of KW-3902 (8-(noradamantan-3-yl)-1, 3-dipropylxanthine), a novel and potent adenosine A,-receptor antagonist, on cisplatin-induced acute renal failure (ARF). ARF was induced in rats by a single injection of cisplatin (5 mg/kg, iv). Prophylactic treatment with KW-3902 (0.01-1 mg/kg, po, twice a day) significantly attenuated the increases of serum creatinine (S-CRE) and urea nitrogen (S-UN) induced by cisplatin. On the other hand, neither furosemide nor trichlormethiazide showed any ameliorating effects against the cisplatin-induced ARF. In the clearance study, the cisplatin-treatment induced marked decreases of glomerular filtration rate (GFR), renal plasma flow (RPF), and reabsorptions of water, sodium and potassium at tubular sites, in comparison with those in untreated normal rats. KW-3902 (0.1 mg/kg, po, twice a day) significantly improved these deteriorated glomerular and tubular functions. In the rats with established cisplatin-induced ARF, KW-3902 ameliorated the cisplatin-induced reductions of GFR, RPF, and reabsorptions of water, sodium and potassium at tubular sites. These results suggest that activation of adenosine A,-receptors is involved in the pathogenesis of cisplatin-induced ARF. The adenosine A,-receptor antagonist may be useful for the treatment of cisplatin-induced ARF.