Rewarding properties of non-competitive and competitive NMDA antagonists as measured by place preference conditioning in rats.

The conditioned place preference paradigm was used to evaluate rewarding properties of non-competitive (MK-801) and competitive (CGP 37849) antagonists of NMDA receptors. Both MK-801 (0.3 mg/kg ip) and CGP 37849 (5, 10, 20 mg/kg ip), administered in association with the initially non-preferred (white) side of the two-arms chamber, caused a significant increase in the time spent on that side in a post-conditioning test. These results show that both non-competitive and competitive antagonists of NMDA receptors are rewarding in animals and may therefore have an abuse potential in humans.