SSRI exerts anxiolytic effect via amygdalar 5-HTergic neural system

2014 Fiscal Year Final Research Report

• Project/Area Number: 24591674
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Psychiatric science
• Research Institution: Hokkaido University
• Principal Investigator: IZUMI TAKESHI 北海道大学, 医学(系)研究科(研究院), 講師 (60312360)
• Co-Investigator(Kenkyū-buntansha): YOSHIDA Takayuki 北海道大学, 大学院医学研究科, 助教 (60374229) ; YOSHIOKA Mitsuhiro 北海道大学, 大学院医学研究科, 教授 (40182729)
• Project Period (FY): 2012-04-01 – 2015-03-31
• Keywords: 不安 / 扁桃体 / 5-HT / SSRI

Outline of Final Research Achievements

The amygdala is a crucial brain structure for anxiety, and it is speculated that the 5-HTergic neural system in this structure has an important role in regulating anxiety. In our previous study, we indicated that systemic administration of selective serotonin reuptake inhibitor (SSRI) had anxiolytic effect in fear-conditioned rats. In the present study, local injection of citalopram, a SSRI, into the bilateral basolateral nucleus of (BLA) attenuated conditioned fear-induced freezing behavior in rats, and this effect was blocked by local co-administration of WAY100635, a selective 5-HT1A antagonist, into the bilateral BLA. Single cell PCR indicated that 6.5% of glutamatergic neurons in BLA had 5-HT1A receptor mRNA, and the resting membrane potential of these neurons were lower than other glutamatergic neurons. From these results, it is suggested that 5-HT increased by SSRI inhibits the part of glutamatergic neurons in BLA, and as a result, SSRI exerts anxiolytic effect.

Free Research Field

精神薬理学