title: Cognitive recovery by chronic activation of the large-conductance calcium-activated potassium channel in a mouse model of Alzheimer's disease.
abstract: We previously showed that activity of the large conductance calcium-activated potassium (Big-K; BK) channels is suppressed in 3xTg Alzheimer disease (AD) model mice. However, its behavioral significance is not known. In the present report, ventricular injection of the BK channel activator isopimaric acid (ISO) was conducted to examine whether BK channel activation ameliorates cognition in 3xTg mice. The novel object recognition (NOR) test revealed that chronic injection of ISO improved non-spatial memory in 3xTg mice. In the Morris water maze, the probe test demonstrated an improved spatial memory after ISO injection. Electrophysiological underpinnings of the ISO effect were then examined in slices obtained from the mice after behavior. At hippocampal CA1 synapses, the basic synaptic transmission was abnormally elevated and long-term potentiation (LTP) was partially suppressed in 3xTg mice. These were both recovered by ISO treatment. We then confirmed suppressed BK channel activity in 3xTg mice by measuring the half-width of evoked action potentials. This was also recovered by ISO treatment. We previously showed that the recovery of BK channel activity accompanies reduction of neuronal excitability in pyramidal cells. Here again, pyramidal cell excitability, as assessed by calculating the frequency of evoked spikes, was elevated in the 3xTg mouse and was normalized by ISO. ELISA experiments demonstrated an ISO-induced reduction of Aβ1-42 content in hippocampal tissue in 3xTg mice. The present study thus suggests a potential therapeutic utility of BK channel activators for AD.
authors.affiliation: Department of Physiology, Kanazawa Medical University, Ishikawa 920-0293, Japan; China-Japan Friendship Hospital, Beijing 100029, China.
authors.forename: Li
authors.initials: L
authors.lastname: Wang
authors.affiliation: Department of Physiology, Kanazawa Medical University, Ishikawa 920-0293, Japan; Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China.
authors.forename: Huicong
authors.initials: H
authors.lastname: Kang
authors.affiliation: Department of Physiology, Kanazawa Medical University, Ishikawa 920-0293, Japan; Fourth Affiliated Hospital, China Medical University, Shenyang 110001, China.
authors.forename: Yongzhi
authors.initials: Y
authors.lastname: Li
authors.affiliation: Department of Physiology, Kanazawa Medical University, Ishikawa 920-0293, Japan; China-Japan Friendship Hospital, Beijing 100029, China.
authors.forename: Yuan
authors.initials: Y
authors.lastname: Shui
authors.affiliation: Department of Physiology, Kanazawa Medical University, Ishikawa 920-0293, Japan.
authors.forename: Ryo
authors.initials: R
authors.lastname: Yamamoto
authors.affiliation: Department of Physiology, Kanazawa Medical University, Ishikawa 920-0293, Japan.
authors.forename: Tokio
authors.initials: T
authors.lastname: Sugai
authors.affiliation: Department of Physiology, Kanazawa Medical University, Ishikawa 920-0293, Japan. Electronic address: kato@kanazawa-med.ac.jp.
authors.forename: Nobuo
authors.initials: N
authors.lastname: Kato
mesh_terms: D000544:Alzheimer Disease / Q000150:complications* / Q000235:genetics; D016229:Amyloid beta-Peptides / Q000378:metabolism; D000818:Animals; D056547:CA1 Region, Hippocampal / Q000187:drug effects / Q000502:physiology; D002264:Carboxylic Acids / Q000627:therapeutic use; D018999:Charybdotoxin / Q000008:administration & dosage; D003072:Cognition Disorders / Q000188:drug therapy / Q000209:etiology* / Q000378:metabolism*; D004195:Disease Models, Animal; D016503:Drug Delivery Systems; D005786:Gene Expression Regulation / Q000187:drug effects / Q000235:genetics; D006801:Humans; D066298:In Vitro Techniques; D051036:Large-Conductance Calcium-Activated Potassium Channels / Q000378:metabolism*; D017774:Long-Term Potentiation / Q000187:drug effects / Q000235:genetics; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D009498:Neurotoxins / Q000008:administration & dosage; D018408:Patch-Clamp Techniques; D010446:Peptide Fragments / Q000378:metabolism; D010616:Phenanthrenes / Q000627:therapeutic use; D021641:Recognition, Psychology / Q000187:drug effects
chemical_list: D016229:Amyloid beta-Peptides; D002264:Carboxylic Acids; D051036:Large-Conductance Calcium-Activated Potassium Channels; D009498:Neurotoxins; D010446:Peptide Fragments; D010616:Phenanthrenes; C075222:amyloid beta-protein (1-42); D018999:Charybdotoxin; C115138:isopimaric acid
keywords: Alzheimer's disease; Excitability; Large conductance calcium-activated potassium channels; Learning and memory; Synaptic plasticity