The dopamine D1 receptor agonist SKF81297 has dose-related effects on locomotor activity but is without effect in a CER trace conditioning procedure conducted with two versus four trials

• Published in: Learning and motivation Vol. 55; pp. 53 - 64
• Main Authors: Pezze, M.A., Marshall, H.J., Cassaday, H.J.
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01-08-2016; Elsevier Limited; Academic Press
• Subjects: Conditioning; Contextual conditioning; Dopamine D1; Drug dosages; Emotional Response; Mental depression; Mental health care; Motivation; Psychological Patterns; Rat; Rodents; SKF81297; Trace conditioning; Dopamine D1; Rat; SKF81297; Trace conditioning; Contextual conditioning
• ISSN: 0023-9690; 1095-9122
• DOI: 10.1016/j.lmot.2016.06.001

In an appetitively motivated procedure, we have previously reported that systemic treatment with the dopamine (DA) D1 receptor agonist SKF81297 (0.4 and 0.8mg/kg) depressed acquisition at a 2s inter-stimulus-interval (ISI), suitable to detect trace conditioning impairment. However since DA is involved in reinforcement processes, the generality of effects across appetitively- and aversively-motivated trace conditioning procedures cannot be assumed. The present study tested the effects of SKF81297 (0.4 and 0.8mg/kg) in an established conditioned emotional response (CER) procedure. Trace-dependent conditioning was clearly shown in two experiments: while conditioning was relatively strong at a 3-s ISI, it was attenuated at a 30-s ISI. This was shown after two (Experiment 1) or four (Experiment 2) conditioning trials conducted in – as far as possible – the same CER procedure. Contrary to prediction, in neither experiment was there any indication that trace conditioning was attenuated by treatment with 0.4 or 0.8mg/kg SKF81297. In the same rats, locomotor activity was significantly enhanced at the 0.8mg/kg dose of SKF81297. These results suggest that procedural details of the trace conditioning variant in use are an important determinant of the profile of dopaminergic modulation.