Strain-dependent effects of fluoxetine on tail suspension test in mice

Abstract

Objective To study the strain difference in response to the antidepressant fluoxetine in mouse tail suspension test. Methods Two outbred mouse strains (KM and ICR) and three inbred mouse strains (C57BL/6, Balb/c and DBA/2) were used in this study. They were treated with the selective serotonin reuptake inhibitor (SSRI) fluoxetine or saline and the immobility time in tail suspension test was recorded. Results There was significant difference of baseline immobility time among different stains with C57BL/6 the most immobile((145.0±16.8)s) and DBA/2 the least((34.5±6.1)s). Fluoxetine significantly decreased the immobility time in C57BL/6((116.0±10.3)s vs (145.0±16.8)s) of control), Balb/c((44.3±6.2)s vs (75.3±10.3)s) of control) and DBA/2 mice((16.6±4.3)s vs (34.5±6.1)s) of control), while the immobile time of KM and ICR mice was not influenced by fluoxetine. Conclusion The effects of fluoxetine in tail suspension test are strain dependent. Fluoxetine exhibits antidepressant effects in C57BL/6, Balb/c and DBA/2 mice, but not in KM and ICR mice. Key words: Tail suspension test; Mouse; Strain; Fluoxetine