Effects of amisulpride on consummatory negative contrast

Abstract

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.

Effects of amisulpride and aripiprazole on progressive-ratio schedule performance: comparison with clozapine and haloperidol

“…The doses of clozapine and haloperidol were chosen on the basis of previous findings of the effects of these drugs on progressive-ratio schedule performance (Mobini et al, 2000; Zhang et al, 2005a). Amisulpride and aripiprazole had not previously been tested in this paradigm; the doses were selected on the basis of published reports of their effects in other behavioural paradigms (Semba et al, 1995; Perrault et al, 1997; Glenn et al, 2002; Ingman et al, 2006; Natesan et al, 2008; Nordquist et al, 2008; see the Discussion section).…”

Animal models and treatments for addiction and depression co-morbidity

“…Fatigue, often combined with psychomotor retardation, is reported in both MDD and psychostimulant withdrawal (Tuma, 1993;Uslaner et al, 1999). The similarities between the two conditions has resulted in the assessment of psychostimulant withdrawal symptoms using diagnostic tools that were designed to quantify depression, such as the Beck Depression Inventory and the Hamilton Rating Scale for Depression (for a fuller discussion of MDD and psychostimulant withdrawal symptomatology, see Barr et al, 2002;Barr and Markou, 2005). Suicidal ideation is also common during psychostimulant withdrawal and MDD (Lowenstein et al, 1987;Kampman et al, 1998).…”

“…Subsequently, the concentration of sucrose is markedly decreased (from 32% to 4%), resulting in decreased consumption levels (Flaherty and Largen, 1975;Barr and Phillips, 2002;Genn et al, 2002). In the negative contrast procedure, rats are allowed to consume a sucrose solution of a given concentration.…”

“…In particular, the affective depression-like aspects of drug withdrawal are considered to be an important motivational factor that perpetuates drug use and dependence Markou and Kenny, 2002). The similarities between psychostimulant withdrawal and major depressive disorder (MDD) in humans have resulted in the development of animal models of aspects of depression based on the effects of psychostimulant withdrawal in rodents (for reviews, see Barr et al, 2002;Barr and Markou, 2005). The observation that drug withdrawal states share several important features with major depression supports this hypothesis (see below).…”

Psychostimulant withdrawal as an inducing condition in animal models of depression

“…Although the psychological constructs that underlie increased immobility in these tasks continue to be debated (Holmes, 2003;Cryan et al, 2002;West, 1990), it is noteworthy that manipulations that induce depressive-like states in humans also increase immobility in these tasks in rodents, and the task has seen increased use recently as a paradigm for measuring 'depressive' symptomatology in rodents (Brotto et al, 2001;Galea et al, 2001), in addition to antidepressant activity Brotto et al, 2000;Page et al, 2003). Furthermore, rats in amphetamine withdrawal displayed a delayed recovery from exposure to a dopaminergically sensitive negative contrast paradigm (Genn et al, 2002), in which the unexpected devaluation in the reinforcing value of a sucrose solution (from 32 to 4%) required longer for drug-treated animals to return to control levels of consumption of the solution , indicating an increased sensitivity to the effects of a psychological stressor and decreased perception of reward (Fig. 4).…”