INDIRECT DOPAMINE AGONISTS EFFECTS ON DESPAIR TEST - DISSOCIATION FROM HYPERACTIVITY

Both dexamphetamine and the pure dopamine reuptake inhibitor GBR 12783 elicit a stimulation of locomotion and increase swimming activity in the behavioral despair test in mice. The dopamine D-1 dopamine recepto r antagonist SCH 23390 dose dependently (7.5-30 mu g/kg SC) antagonize d the stimulant locomotor effect of both drugs but did nor prevent the ir antiimmobility effect on the behavioral despair test. The D-2 dopam ine receptor antagonist haloperidol dose dependently (12.5-50 mu g/kg IP) antagonized the effects of dexamphetamine on both locomotor activi ty and behavioral despair test. By contrast, haloperidol inhibited the effects of GBR 12783 in the forced swimming test but not on locomotio n. It is concluded that indirect dopamine agonists are effective on th e behavioral despair test independently of a stimulation of locomotor activity. Their effects on the despair test depend on the stimulation of D-2 but not D-1 dopamine receptors.