title: Fear conditioning suppresses large-conductance calcium-activated potassium channels in lateral amygdala neurons.
abstract: It was previously shown that depression-like behavior is accompanied with suppression of the large-conductance calcium activated potassium (BK) channel in cingulate cortex pyramidal cells. To test whether BK channels are also involved in fear conditioning, we studied neuronal properties of amygdala principal cells in fear conditioned mice. After behavior, we made brain slices containing the amygdala, the structure critically relevant to fear memory. The resting membrane potential in lateral amygdala (LA) neurons obtained from fear conditioned mice (FC group) was more depolarized than in neurons from naïve controls. The frequencies of spikes evoked by current injections were higher in neurons from FC mice, demonstrating that excitability of LA neurons was elevated by fear conditioning. The depolarization in neurons from FC mice was shown to depend on BK channels by using the BK channel blocker charybdotoxin. Suppression of BK channels in LA neurons from the FC group was further confirmed on the basis of the spike width, since BK channels affect the descending phase of spikes. Spikes were broader in the FC group than those in the naïve control in a manner dependent on BK channels. Consistently, quantitative real-time PCR revealed a decreased expression of BK channel mRNA. The present findings suggest that emotional disorder manifested in the forms of fear conditioning is accompanied with BK channel suppression in the amygdala, the brain structure critical to this emotional disorder.
authors.affiliation: Department of Physiology, Kanazawa Medical University, Ishikawa 920-0293, Japan; Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
authors.forename: P
authors.initials: P
authors.lastname: Sun
authors.affiliation: Department of Physiology, Kanazawa Medical University, Ishikawa 920-0293, Japan; Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
authors.forename: Q
authors.initials: Q
authors.lastname: Zhang
authors.affiliation: Department of Physiology, Kanazawa Medical University, Ishikawa 920-0293, Japan; Medical College, Qinghai University, Xining, China.
authors.forename: Y
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Department of Physiology, Kanazawa Medical University, Ishikawa 920-0293, Japan; Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
authors.forename: F
authors.initials: F
authors.lastname: Wang
authors.affiliation: Department of Physiology, Kanazawa Medical University, Ishikawa 920-0293, Japan; China-Japan Friendship Hospital, Beijing, China.
authors.forename: L
authors.initials: L
authors.lastname: Wang
authors.affiliation: Department of Physiology, Kanazawa Medical University, Ishikawa 920-0293, Japan.
authors.forename: R
authors.initials: R
authors.lastname: Yamamoto
authors.affiliation: Department of Physiology, Kanazawa Medical University, Ishikawa 920-0293, Japan.
authors.forename: T
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: N
authors.initials: N
authors.lastname: Kato
mesh_terms: D000679:Amygdala / Q000187:drug effects / Q000502:physiology*; D000818:Animals; D018999:Charybdotoxin / Q000494:pharmacology; D003213:Conditioning, Psychological / Q000187:drug effects / Q000502:physiology*; D005239:Fear / Q000187:drug effects / Q000502:physiology*; D046352:Freezing Reaction, Cataleptic / Q000502:physiology; D051036:Large-Conductance Calcium-Activated Potassium Channels / Q000037:antagonists & inhibitors / Q000378:metabolism*; D008297:Male; D008564:Membrane Potentials / Q000187:drug effects / Q000502:physiology; D008810:Mice, Inbred C57BL; D009043:Motor Activity / Q000502:physiology; D009474:Neurons / Q000187:drug effects / Q000502:physiology*; D026902:Potassium Channel Blockers / Q000494:pharmacology; D012333:RNA, Messenger / Q000378:metabolism; D060888:Real-Time Polymerase Chain Reaction; D046509:Tissue Culture Techniques
chemical_list: D051036:Large-Conductance Calcium-Activated Potassium Channels; D026902:Potassium Channel Blockers; D012333:RNA, Messenger; D018999:Charybdotoxin
keywords: Amygdala; Calcium-activated potassium channel; Excitability; Fear conditioning