title: An in vitro reproduction of stress-induced memory defects: Effects of corticoids on dendritic spine dynamics.
abstract: Previously, in organotypic slice culture of rodent hippocampus we found that three repeated inductions of LTP, but not a single induction, led to a slow-developing long-lasting enhancement of synaptic strength coupled with synapse formation. Naming this structural plasticity RISE (repetitive LTP-induced synaptic enhancement) and assuming it to be a potential in vitro reproduction of repetition-dependent memory consolidation, we are analyzing its cellular mechanisms. Here, we applied a glucocorticoid to the culture to mimic acute excess stress and demonstrated its blockade of RISE. Since excess stress interferes with behavioral memory consolidation, the parallelism between RISE in vitro and memory consolidation in vivo is supported. We recently reported that RISE developed after stochastic processes. Here we found that the glucocorticoid interfered with RISE by suppressing the increment of dendritic spine fluctuation that precedes a net increase in spine density. The present study provides clues for understanding the mechanism of stress-induced memory defects.
authors.affiliation: Laboratory of Synaptic Plasticity, Osaka University Graduate School of Frontier Biosciences, Suita, Osaka 565-0871 Japan.
authors.forename: Shinichi
authors.initials: S
authors.lastname: Saito
authors.affiliation: Laboratory of Synaptic Plasticity, Osaka University Graduate School of Frontier Biosciences, Suita, Osaka 565-0871 Japan.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Kimura
authors.affiliation: National Center of Neurology and Psychiatry, Kodaira 187-8551 Tokyo, Japan.
authors.forename: Naoki
authors.initials: N
authors.lastname: Adachi
authors.affiliation: National Center of Neurology and Psychiatry, Kodaira 187-8551 Tokyo, Japan.
authors.forename: Tadahiro
authors.initials: T
authors.lastname: Numakawa
authors.affiliation: Laboratory of Synaptic Plasticity, Osaka University Graduate School of Frontier Biosciences, Suita, Osaka 565-0871 Japan.
authors.forename: Akihiko
authors.initials: A
authors.lastname: Ogura
authors.affiliation: Laboratory of Synaptic Plasticity, Osaka University Graduate School of Frontier Biosciences, Suita, Osaka 565-0871 Japan.
authors.forename: Keiko
authors.initials: K
authors.lastname: Tominaga-Yoshino
mesh_terms: D000305:Adrenal Cortex Hormones / Q000494:pharmacology*; D000818:Animals; D049229:Dendritic Spines / Q000187:drug effects* / Q000378:metabolism*; D006624:Hippocampus / Q000187:drug effects / Q000378:metabolism / Q000503:physiopathology; D017774:Long-Term Potentiation / Q000187:drug effects; D008569:Memory Disorders / Q000188:drug therapy / Q000209:etiology* / Q000523:psychology*; D051379:Mice; D013312:Stress, Physiological; D013315:Stress, Psychological; D013569:Synapses / Q000187:drug effects / Q000378:metabolism
chemical_list: D000305:Adrenal Cortex Hormones