Modulation of recognition and temporal order memory retrieval by dopamine D1 receptor in rats

The present study examines the effects of SKF 81297, a selective D, agonist, on information retrieval in recognition and temporal order memory for objects, using three different tasks. Separate groups of rats were trained in each task and then given an intraperitoneal injection of saline or the D, agonist (0.03, 0.3 mg/kg), before the memory testing trial in an object recognition, object location, and object temporal order memory tasks. We show that SKF 81297, at high dose (0.3 mg/kg), facilitates information retrieval after a long delay (4h) in the three memory tasks whereas both high and low doses of D, agonist impair recognition memory after a short delay (15 min). These results indicate a significant role of dopamine D-1 receptors in recognition memory for both familiarity and place of objects in addition to object temporal order memory. (c) 2005 Elsevier Inc. All rights reserved.