“…The animal data suggesting adenosine receptormediated antinociception are being reviewed elsewhere in this issue. In brief, abundant studies in rodents have demonstrated a delay in withdrawal tests for noxious stimuli [Sawynok and Sweeney, 1989;Sawynok, 1998], in normal tissue and in tissues compromised by peripheral inflammation [Karlsten et al, 1992a], peripheral and central nerve injury [Lee and Yaksh, 1996;Sjölund et al, 1996Sjölund et al, , 1997Sjölund et al, , 1998Cui et al, 1997Cui et al, , 1998], or during anesthesia [Birch et al, 1988;Seitz et al, 1990]. However, there are difficulties in translating these experimental data into the clinic.…”