Influence of sex and corticotropin-releasing factor pathways as determinants in serotonin sensitivity. Journal Article uri icon



  • Stress sensitivity and sex are predictive factors in affective disorder susceptibility. Serotonin (5-HT) pathway recruitment by corticotropin-releasing factor (CRF) during stress is necessary in adaptive coping behaviors, but sex differences in such responses have not been investigated. Using selective 5-HT reuptake inhibitor (SSRI) administration to acutely elevate 5-HT in a genetic model of stress sensitivity, we examined behavioral and physiological responses in male and female stress-sensitive CRF receptor-2-deficient (R2KO) mice. Chronic SSRI treatment was used to confirm outcomes were specific to acute 5-HT elevation and not antidepressant efficacy. We hypothesized that R2KO mice would show a greater sensitivity to acute changes in 5-HT and that, because females typically are more stress sensitive, R2KO females would be the most responsive. Our results supported this hypothesis because females of both genotypes and R2KO males showed a greater sensitivity to an acute 10 mg/kg dose of citalopram in a tail suspension test, displaying decreased immobile time and increased latency to immobility. Furthermore, acute citalopram promoted significant anxiogenic-like effects that were specific to R2KO females in the elevated plus maze and light-dark box tests. Chronic citalopram did not produce these behavioral changes, supporting specificity to acute 5-HT modulation. Mechanistically, females had decreased hippocampal 5-HT transporter (SERT) levels, whereas R2KO mice showed reduced SERT in the prefrontal cortex, supporting a possible intersection of sex and genotype where R2KO females would have the lowest SERT to be blocked by the SSRI. This sensitivity to 5-HT-mediated anxiety in females may underlie a heightened vulnerability to stress-related affective disorders.

publication date

  • August 1, 2009

has subject area

Date in CU Experts

  • March 13, 2015 1:51 AM

Full Author List

  • McEuen JG; Semsar KA; Lim MA; Bale TL

author count

  • 4

citation count

  • 14

Other Profiles

International Standard Serial Number (ISSN)

  • 0013-7227

Electronic International Standard Serial Number (EISSN)

  • 1945-7170

Additional Document Info

start page

  • 3709

end page

  • 3716


  • 150


  • 8