Glucocorticoid effects on working memory impairment require l-type calcium channel activity within prefrontal cortex

• Published in: Neurobiology of learning and memory 2023-01, Vol.197, p.107700-107700, Article 107700
• Main Authors: Barsegyan, Areg, McGaugh, James L., Roozendaal, Benno
• Format: Article
• Language: English
• Subjects: Animals; Calcium Channels, L-Type - metabolism; Diltiazem - metabolism; Diltiazem - pharmacology; Glucocorticoids; Glucocorticoids - pharmacology; l-type voltage-gated calcium channel; Male; Memory Disorders; Memory, Short-Term - physiology; PKA; Prefrontal cortex; Prefrontal Cortex - physiology; Rats; Rats, Sprague-Dawley; Working memory
• ISSN: 1074-7427; 1095-9564
• DOI: 10.1016/j.nlm.2022.107700

•Glucocorticoid administration into prefrontal cortex impairs working memory.•This glucocorticoid effect requires concurrent protein kinase A (PKA) activity.•PKA is known to activate l-type voltage-gated Ca2+ channels (LTCCs)•We examined glucocorticoid and PKA interactions with LTCCs on working memory.•Inhibition of LTCCs in PFC blocked glucocorticoid and PKA effects on working memory. Previous findings have indicated that glucocorticoid hormones impair working memory via an interaction with the β-adrenoceptor-cAMP signaling cascade to rapidly increase cAMP-dependent protein kinase (PKA) activity within the prefrontal cortex (PFC). However, it remains elusive how such activation of PKA can affect downstream cellular mechanisms in regulating PFC cognitive function. PKA is known to activate l-type voltage-gated Ca2+ channels (LTCCs) which regulate a broad range of cellular processes, including neuronal excitability and neurotransmitter release. The present experiments examined whether LTCC activity within the PFC is required in mediating glucocorticoid and PKA effects on spatial working memory. Male Sprague Dawley rats received bilateral administration of the LTCC inhibitor diltiazem together with either the glucocorticoid receptor agonist RU 28362 or PKA activator Sp-cAMPS into the PFC before testing on a delayed alternation task in a T-maze. Both RU 28362 and Sp-cAMPS impaired working memory, whereas the LTCC inhibitor diltiazem fully blocked the working memory impairment induced by either RU 28362 or Sp-cAMPS. Conversely, bilateral administration of the LTCC agonist Bay K8644 into the PFC was sufficient to impair working memory. Thus, these findings provide support for the view that glucocorticoids, via an interaction with the β-adrenergic signaling cascade and enhanced PKA activity levels, impair working memory by increasing LTCC activity in the PFC.