Blocking Dopaminergic Signaling Soon after Learning Impairs Memory Consolidation in Guinea Pigs.
Formation of episodic memories (i.e. remembered experiences) requires a process called consolidation which involves communication between the neocortex and hippocampus. However, the neuromodulatory mechanisms underlying this neocortico-hippocampal communication are poorly understood. Here, we examined the involvement of dopamine D1 receptors (D1R) and D2 receptors (D2R) mediated signaling on memory consolidation using the Novel Object Recognition (NOR) test. We conducted the tests in male Hartley guinea pigs and cognitive behaviors were assessed in customized Phenotyper home cages utilizing Ethovision XT software from Noldus enabled for the 3-point detection system (nose, center of the body, and rear). We found that acute intraperitoneal injections of either 0.25 mg/kg SCH23390 to block D1Rs or 1.0 mg/kg sulpiride to block D2Rs soon after acquisition (which involved familiarization to two similar objects) attenuated subsequent discrimination for novel objects when tested after 5-hours in the NOR test. By contrast guinea pigs treated with saline showed robust discrimination for novel objects indicating normal operational processes undergirding memory consolidation. The data suggests that involvement of dopaminergic signaling is a key post-acquisition factor in modulating memory consolidation in guinea pigs.
Department of Neuroscience and Pharmacology, Meharry Medical College, 1005 DB Todd Boulevard, Nashville, TN, 37208, United States of America.
Kiera-Nicole
KN
Lee
Department of Neuroscience and Pharmacology, Meharry Medical College, 1005 DB Todd Boulevard, Nashville, TN, 37208, United States of America; Department of Pharmacology, 23rd Avenue South & Pierce, Vanderbilt University, Nashville, TN, 37203, United States of America.
Sanika
S
Chirwa
D000818:Animals; D001552:Benzazepines / Q000494:pharmacology; D065127:Dopamine D2 Receptor Antagonists / Q000494:pharmacology; D006168:Guinea Pigs; D008297:Male; D000069077:Memory Consolidation / Q000187:drug effects / Q000502:physiology*; D009043:Motor Activity / Q000187:drug effects; D017447:Receptors, Dopamine D1 / Q000037:antagonists & inhibitors / Q000378:metabolism*; D017448:Receptors, Dopamine D2 / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects; D013469:Sulpiride / Q000494:pharmacology
D001552:Benzazepines; D065127:Dopamine D2 Receptor Antagonists; D017447:Receptors, Dopamine D1; D017448:Receptors, Dopamine D2; C534628:SCH 23390; D013469:Sulpiride