Ontogenetic Quinpirole Treatment Produces Spatial Memory Deficits and Reaching Accuracy Enhancement in Rats

Past studies have shown that ontogenetic treatment of quinpirole (QNP) produces a number of behavioral effects that can be alleviated by administration of antipsychotics such as haloperidol, providing a useful behavioral screen for disorders such as schizophrenia. In this study, 16 female Sprague-dawley rats were used, with 8 rats injected with QNP(1 mg/kg) and 8 rats injected with saline once daily from postnatal days (PD) 1-11. All rats were behaviorally tested as adults on several tasks: The reference and working memory versions of the Morris water task (MWT), the radial arm maze (RAM), the Whishaw reaching task, and locomotor activity. Results showed that on the MWT, QNP-treated rats demonstrated significant enhancement on acquisition latency of both versions, but a deficit on the probe trial of the reference memory version. The acquisition enhancement was due to hyperlocomotion observed in QNP-treated rats, because these animals demonstrated increased locomotion in an activity chamber compared to controls. On the RAM, QNP-treated rats demonstrated a deficit in reference memory but not working memory, congruent with MWT findings. Interestingly, QNP-treated rats demonstrated a significant enhancement in reaching accuracy on the Whishaw reaching task, which may due to an overactive dopaminergic system. Future studies will analyze underlying mechanisms