GABAA and dopamine receptors in the nucleus accumbens shell differentially influence performance of a water-reinforced progressive ratio task

► Progressive ratio performance examined after drug injections in accumbens shell. ► Amphetamine increased responding for water reward. ► The amphetamine effect was due to increased duration of sessions. ► Muscimol increased food intake, but did not increase responding for water. ► We conclude that inactivation of the shell does not increase willingness to work for water.