title: Local infusion of citalopram into the basolateral amygdala decreased conditioned fear of rats through increasing extracellular serotonin levels.
abstract: Selective serotonin reuptake inhibitors (SSRIs) are widely used for the treatment of depressive disorders and anxiety disorders. The anxiolytic mechanism of SSRIs is currently unclear. To investigate the anxiolytic effects of SSRIs, we measured both freezing behavior and extracellular serotonin and dopamine levels in the basolateral amygdala when rats were given conditioned fear stress under local reverse-dialysis of citalopram, an SSRI, into the basolateral amygdala. Local administration of citalopram into the basolateral amygdala significantly decreased freezing behavior induced by conditioned fear stress, and serotonin levels were simultaneously found to be significantly higher. Furthermore, repeated conditioned fear stress under local infusion of citalopram into the basolateral amygdala induced further increases in extracellular dopamine levels. Further studies investigating the role of dopamine in the amygdala for conditioned fear stress will be necessary. These results suggest that the basolateral amygdala is one of the target areas of the anxiolytic effects of citalopram and the increases of extracellular serotonin levels in the basolateral amygdala may be related to the anxiolytic effects.
authors.affiliation: Department of Psychiatry, Hokkaido University Graduate School of Medicine, North 15, West 7, Kita-ku, Sapporo 060-8638, Japan. Electronic address: muenchen-yuji@huhp.hokudai.ac.jp.
authors.forename: Yuji
authors.initials: Y
authors.lastname: Kitaichi
authors.affiliation: Department of Psychiatry, Hokkaido University Graduate School of Medicine, North 15, West 7, Kita-ku, Sapporo 060-8638, Japan.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Inoue
authors.affiliation: Department of Psychiatry, Hokkaido University Graduate School of Medicine, North 15, West 7, Kita-ku, Sapporo 060-8638, Japan.
authors.forename: Shin
authors.initials: S
authors.lastname: Nakagawa
authors.affiliation: Department of Psychiatry, Hokkaido University Graduate School of Medicine, North 15, West 7, Kita-ku, Sapporo 060-8638, Japan.
authors.forename: Yuki
authors.initials: Y
authors.lastname: Omiya
authors.affiliation: Department of Psychiatry, Hokkaido University Graduate School of Medicine, North 15, West 7, Kita-ku, Sapporo 060-8638, Japan.
authors.forename: Ning
authors.initials: N
authors.lastname: Song
authors.affiliation: Department of Psychiatry, Hokkaido University Graduate School of Medicine, North 15, West 7, Kita-ku, Sapporo 060-8638, Japan.
authors.forename: Yan
authors.initials: Y
authors.lastname: An
authors.affiliation: Department of Psychiatry, Hokkaido University Graduate School of Medicine, North 15, West 7, Kita-ku, Sapporo 060-8638, Japan.
authors.forename: Chong
authors.initials: C
authors.lastname: Chen
authors.affiliation: Department of Psychiatry, Hokkaido University Graduate School of Medicine, North 15, West 7, Kita-ku, Sapporo 060-8638, Japan.
authors.forename: Ichiro
authors.initials: I
authors.lastname: Kusumi
authors.affiliation: Department of Psychiatry, Hokkaido University Graduate School of Medicine, North 15, West 7, Kita-ku, Sapporo 060-8638, Japan.
authors.forename: Tsukasa
authors.initials: T
authors.lastname: Koyama
mesh_terms: D000818:Animals; D066272:Basolateral Nuclear Complex / Q000187:drug effects* / Q000503:physiopathology; D015283:Citalopram / Q000494:pharmacology*; D003213:Conditioning, Psychological / Q000187:drug effects* / Q000502:physiology; D004298:Dopamine / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D005110:Extracellular Space / Q000187:drug effects / Q000378:metabolism; D005239:Fear / Q000187:drug effects* / Q000502:physiology; D046352:Freezing Reaction, Cataleptic / Q000187:drug effects / Q000502:physiology; D008297:Male; D017207:Rats, Sprague-Dawley; D012701:Serotonin / Q000378:metabolism*; D017367:Selective Serotonin Reuptake Inhibitors / Q000494:pharmacology*; D013315:Stress, Psychological / Q000188:drug therapy / Q000503:physiopathology
chemical_list: D015283:Citalopram; D004298:Dopamine; D012701:Serotonin; D017367:Selective Serotonin Reuptake Inhibitors
keywords: Amygdala; Citalopram; Conditioned fear stress; Dopamine; Serotonin