title: Estrogen effects on the forced swim test differ in two outbred rat strains.
abstract: Changes in reproductive hormones, such as estrogen, play a role in mood regulation. The present study examined strain differences (Long-Evans vs. Wistar-Hannover) in the behavioral and biochemical effects of estrogen manipulation. Adult ovariectomized female rats were treated with estradiol, vehicle, or withdrawn from estradiol. The two strains demonstrated differential behavioral responses to short-term estradiol administration in the forced swim test; estradiol induced an antidepressant-like effect in Long-Evans rats but not in Wistar rats. Conversely, withdrawal from estradiol resulted in a depressive-like state in the Wistar rats but not in the Long-Evans rats. Western blot analyses found no differences in estrogen receptors α and β within the hippocampus or the frontal cortex, two brain areas strongly implicated in affective disorders. These data demonstrate the importance of strain as a variable when interpreting behavioral effects of estrogen.
authors.affiliation: National Institute of Mental Health, National Institutes of Health, Department of Health and Human Services, Bethesda, MD 20892-1276, USA. wkoss2@illinois.edu
authors.forename: Wendy A
authors.initials: WA
authors.lastname: Koss
authors.forename: Haim
authors.initials: H
authors.lastname: Einat
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Schloesser
authors.forename: Husseini K
authors.initials: HK
authors.lastname: Manji
authors.forename: David R
authors.initials: DR
authors.lastname: Rubinow
mesh_terms: D000818:Animals; D004958:Estradiol / Q000097:blood / Q000494:pharmacology; D047628:Estrogen Receptor alpha / Q000378:metabolism*; D047629:Estrogen Receptor beta / Q000378:metabolism*; D004967:Estrogens / Q000494:pharmacology / Q000502:physiology*; D005260:Female; D005625:Frontal Lobe / Q000187:drug effects / Q000378:metabolism; D006624:Hippocampus / Q000187:drug effects / Q000378:metabolism; D046353:Immobility Response, Tonic / Q000187:drug effects / Q000502:physiology*; D051381:Rats; D020318:Rats, Long-Evans; D017208:Rats, Wistar; D013045:Species Specificity; D013375:Substance Withdrawal Syndrome / Q000523:psychology
chemical_list: D047628:Estrogen Receptor alpha; D047629:Estrogen Receptor beta; D004967:Estrogens; D004958:Estradiol