title: Glucocorticoid enhancement of dorsolateral striatum-dependent habit memory requires concurrent noradrenergic activity.
abstract: Previous findings indicate that post-training administration of glucocorticoid stress hormones can interact with the noradrenergic system to enhance consolidation of hippocampus- or amygdala-dependent cognitive/emotional memory. The present experiments were designed to extend these findings by examining the potential interaction of glucocorticoid and noradrenergic mechanisms in enhancement of dorsolateral striatum (DLS)-dependent habit memory. In experiment 1, different groups of adult male Long-Evans rats received training in two DLS-dependent memory tasks. In a cued water maze task, rats were released from various start points and were reinforced to approach a visibly cued escape platform. In a response-learning version of the water plus-maze task, animals were released from opposite starting positions and were reinforced to make a consistent egocentric body-turn to reach a hidden escape platform. Immediately post-training, rats received peripheral injections of the glucocorticoid corticosterone (1 or 3 mg/kg) or vehicle solution. In both tasks, corticosterone (3 mg/kg) enhanced DLS-dependent habit memory. In experiment 2, a separate group of animals received training in the response learning version of the water plus-maze task and were given peripheral post-training injections of corticosterone (3 mg/kg), the β-adrenoreceptor antagonist propranolol (3 mg/kg), corticosterone and propranolol concurrently, or control vehicle solution. Corticosterone injections again enhanced DLS-dependent memory, and this effect was blocked by concurrent administration of propranolol. Propranolol administration by itself (3 mg/kg) did not influence DLS-dependent memory. Taken together, the findings indicate an interaction between glucocorticoid and noradrenergic mechanisms in DLS-dependent habit memory. Propranolol administration may be useful in treating stress-related human psychopathologies associated with a dysfunctional DLS-dependent habit memory system.
authors.affiliation: Department of Psychology and Institute for Neuroscience, Texas A&M University, United States.
authors.forename: J
authors.initials: J
authors.lastname: Goodman
authors.affiliation: Department of Psychology and Institute for Neuroscience, Texas A&M University, United States.
authors.forename: K-C
authors.initials: KC
authors.lastname: Leong
authors.affiliation: Department of Psychology and Institute for Neuroscience, Texas A&M University, United States. Electronic address: markpackard@tamu.edu.
authors.forename: M G
authors.initials: MG
authors.lastname: Packard
mesh_terms: D000319:Adrenergic beta-Antagonists / Q000494:pharmacology; D000818:Animals; D003342:Corpus Striatum / Q000187:drug effects / Q000378:metabolism*; D003345:Corticosterone / Q000008:administration & dosage / Q000378:metabolism*; D003463:Cues; D004305:Dose-Response Relationship, Drug; D005938:Glucocorticoids / Q000378:metabolism*; D006184:Habits; D008297:Male; D018782:Maze Learning / Q000187:drug effects / Q000502:physiology; D008568:Memory / Q000187:drug effects / Q000502:physiology*; D011433:Propranolol / Q000494:pharmacology; D020318:Rats, Long-Evans; D011943:Receptors, Adrenergic, beta / Q000378:metabolism*; D012054:Reinforcement, Psychology
chemical_list: D000319:Adrenergic beta-Antagonists; D005938:Glucocorticoids; D011943:Receptors, Adrenergic, beta; D011433:Propranolol; D003345:Corticosterone
keywords: corticosterone; habit; memory; propranolol; stress; striatum