Effects of the A2A adenosine receptor antagonist KW6002 in the nucleus accumbens in vitro and in vivo

In this study, we have used the selective A2A adenosine receptor antagonist KW6002 to investigate the function of A2A receptors in the Lister hooded rat nucleus accumbens in vitro and in vivo. Radioligand binding studies confirmed a greater than 50-fold selectivity of KW6002 for A2A receptors compared to A1 receptors. Release of [3H]-dopamine from nucleus accumbens slices in vitro was almost doubled in the presence of 300 nM KW6002, while GABA release was inhibited by approximately one third. In vivo, intraperitoneal administration of KW6002 (4 mg kg− 1) increased dopamine overflow almost 4-fold in the nucleus accumbens. In behavioural testing, KW6002 elicited place preference and increased locomotor activity at 1, 2 and 4 mg kg− 1. Taken together, these results suggest a role for tonic activation of A2A adenosine receptors in reward-related phenomena.