[Influence of estradiol on tryptophan hydroxylase and 5-hydroxytryptamine content in raphe nuclei of rats under forced swimming stress].
OBJECTIVE
To investigate the effect of estradiol (E2) on tryptophan hydroxylase (TPH) and 5-hydroxytryptamine (5-HT) content in raphe nuclei of rats under forced swimming stress and explore the role of estrogen and stress in disease mechanism of depression in women.


METHODS
At Week 3 post-ovariectomy, 35 ovariectomized (OVX) female SD rats were randomly divided into 5 groups (n = 7): non-stress group, control group, estradiol (E2) group and fluoxetine (FLX) group and E2 plus FLX group. Animals were administered with different drugs for 2 weeks. At Day 14, animals except those in the non-stress group were subjected to the 15 min forced swimming test (FST). At 2 hours post-FST, all animals including those in the non-stress group were perfused with 4% paraformaldehyde and brains removed for TPH and 5-HT immunofluorescence staining. We compared the content of TPH and 5-HT by observing and calculating the integrated optical density (IOD) of immunofluorescent-positive signals in raphe nuclei.


RESULTS
(1) The IOD value of TPH- and 5-HT-positive region in raphe nuclei of rats in the control group was significantly lower than that of the non-stress group (P < 0.01); (2) the IOD value of TPH- and 5-HT-positive region in raphe nuclei of rats in the E2, FLX and E2 plus FLX groups was significantly higher than that in the control group (P < 0.05).


CONCLUSIONS
Forced swimming stress can decrease the TPH and 5-HT content in raphe nuclei. Such changes can be prevented by a pre-administration of estradiol. Similar results are observed with antidepressant fluoxetine. These effects may underlie the role of estradiol and stress in the disease mechanism of depression in women.
Yang
Fu-zhong
FZ
Psychiatry Department of Huashan Hospital, Fudan University, Shanghai 200030, China.
Wu
Yan
Y
Zhang
Wei-guo
WG
Cai
Yi-yun
YY
Shi
Shen-xun
SX
D000818:Animals; D004958:Estradiol / Q000494:pharmacology*; D005260:Female; D005473:Fluoxetine / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012701:Serotonin / Q000378:metabolism*; D013312:Stress, Physiological; D013550:Swimming; D014365:Tryptophan Hydroxylase / Q000378:metabolism*
D005473:Fluoxetine; D012701:Serotonin; D004958:Estradiol; D014365:Tryptophan Hydroxylase