Further study of the effects of dopaminergic D1 drugs on place avoidance behavior using pretraining: some negative evidence.

Dopaminergic neurotransmission is considered to modulate cognitive processes, including spatial memory. The aim of this study was to further evaluate the role of the D1 receptor system in an active allothetic place avoidance (AAPA) task using pretrained rats. Our previous results showed enhanced AAPA learning after systemic injections of low doses of D1 agonist A77636, and the impairment of AAPA acquisition by D1 blocker SCH23390 [Stuchlik A, Vales K. Effect of dopamine D1 receptor antagonist SCH23390 and agonist A77636 on active allothetic place avoidance, a spatial cognition task. Behav Brain Res 2006;172(2):250-255]. In the present study, we used the intact-pretraining paradigm, in which animals were trained to the task prior to the injections and subsequently retrieval and reacquisition of AAPA while under the effects of the drugs was tested. Results showed that the intact pretraining partly eliminated the effects of A77636 and SCH23390 on AAPA performance, but a higher dose of SCH23390 caused a motor deficit in the retrieval session. We conclude that in the previous study, D1-active drugs may have had influence upon the non-spatial aspects of the AAPA.