Comparison of the effects of antipsychotic drugs in two antipsychotic screening assays: swim-induced grooming and apomorphin climbing test in mice

The antagonism of apomorphine-induced climbing behaviour and sniffing and the swim-induced grooming test are widely used models for screening antipsychotic drugs. It is hypothesized that blockade of climbing behaviour evoked by apomorphine is related to the dopamine receptor blockade in the nucleus accumbens and antagonism of stereotyped sniffing produced by apomorphine is related to the blockade of dopamine D2 receptors in the striatum [1]. The dopamine receptor antagonist antipsychotics inhibit both apomorphineinduced behaviours, although compounds with strong 5-HT2A inhibitory effect show higher potency in blocking the climbing vs. the sniffing response. The grooming behaviour induced by immersion in water involves mainly dopamine D1 receptors [2]. This behaviour is inhibited in a dose dependent manner by dopamine receptor antagonists. [3]. The aim of our study was to compare these two screen assays in terms of their sensitivity to the actions of various antipsychotic compounds. We investigated the effect of a conventional neuroleptic (haloperidol), atypical antipsychotics (clozapine, olanzapine, risperidone, ziprasidone, amisulpride) and new generation, partial D2 agonist antipsychotics (arpiprazole, bifeprunox) in these screening methods.