Effects of amisulpride on consummatory negative contrast

Two groups of rats, 'shifted' (32-4% sucrose) and 'unshifted' (4-4% sucrose), were given access to sucrose solutions for 5 min/day for 10 days. On day 11, shifted animals had access to a devalued incentive (4% sucrose) and subgroups of each group received doses of amisulpride (10 or 60 mg/kg, i.p.) or its vehicle before a 10-min access period to sucrose solutions. Lick frequency was measured both pre- and post-shift. A high dose of amisulpride reduced successive negative contrast (SNC) after a brief period of exposure to the devalued stimulus, whereas a low dose had no effect. The acute effects of high doses of amisulpride seem to act on contrast effects in a similar way to anxiolytic compounds such as the benzodiazepine, chlordiazepoxide.