Glucocorticoid-induced impairment of long-term memory retrieval in rats: An interaction with dopamine D2 receptors

• Published in: Neurobiology of learning and memory Vol. 85; no. 3; pp. 300 - 306
• Main Authors: Pakdel, Roghayeh, Rashidy-Pour, Ali
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier Inc 01.05.2006; Elsevier; Elsevier BV
• Subjects: Animal; Animals; Behavioral psychophysiology; Biological and medical sciences; Corticosterone; Corticosterone - administration & dosage; Corticosterone - adverse effects; Dopamine receptors; Fundamental and applied biological sciences. Psychology; Glucocorticoids - administration & dosage; Glucocorticoids - adverse effects; Inhibitory avoidance task; Learning. Memory; Locomotion - drug effects; Male; Memory; Memory Disorders - chemically induced; Memory retrieval; Neurotransmission and behavior; Psychology. Psychoanalysis. Psychiatry; Psychology. Psychophysiology; Random Allocation; Rats; Rats, Wistar; Receptors, Dopamine D2 - drug effects; Memory retrieval; Inhibitory avoidance task; Corticosterone; Dopamine receptors; Rat; Steroid hormone; Dopamine receptor; Interaction; Rodentia; Glucocorticoid; Long term; Vertebrata; Mammalia; D2 Dopamine receptor; Animal; Adrenal hormone; Long term memory; Inhibition; Avoidance
• ISSN: 1074-7427; 1095-9564
• DOI: 10.1016/j.nlm.2005.12.003

This study investigated glucocorticoid–dopaminergic interactions in modulating retrieval of long-term memory in an inhibitory avoidance task. Young adult male rats were trained in one trial inhibitory avoidance task (0.5 mA, 3 s footshock). On the retention test given 48 h after training, the latency to re-enter the dark compartment of the apparatus was recorded. Systemically administered corticosterone (1 or 3 mg/kg) given to rats 30 min before retention testing impaired their memory retrieval, but the lower dose was more effective than the higher one. Administration of the dopamine (DA) D2 receptor antagonist sulpiride (6 or 20 mg/kg) 30 min before corticosterone attenuated the impairing effects of corticosterone (1 mg/kg) on memory retrieval. Administration of the DA D1 receptor antagonist SCH23390 (25 or 50 μg/kg) had no effect on corticosterone-induced impairment of memory retrieval. Further, applied doses of sulpiride or SCH23390 alone were ineffective in modulating memory retrieval. These findings provide evidence for the existence of an interaction between glucocorticoids and DA D2 receptor on memory retrieval process.