title: Effects of chronic mild stress on sexual behavior, locomotor activity and consumption of sucrose and saccharine solutions.
abstract: Many symptoms of human depressive disorders are also observed in animals after exposure to unpredictable stressors. The chronic mild stress (CMS) paradigm was developed in order to better model the human situation by using chronic mild stressors over a longer period. It is claimed that the model induces anhedonia in the animals, a core symptom of depression in humans. Despite the fact that the CMS model has a high degree of face validity, there are a number of laboratories in which the establishment of the model is less reliably observed. We have examined behavior (sexual activity and open field activity) together with hedonic measures (sucrose and saccharine intake) after exposure to CMS. CMS decreased male sexual activity (e.g. reduced capability to ejaculate) and increased activity in an open field test. The hedonic measures showed diverging results after CMS in our laboratory. Sucrose consumption was reduced, while saccharine consumption did not show a comparable change. It is concluded that CMS induces comparable alterations to some depression-like symptoms in humans. Saccharine consumption is not a reliable indicator of the hedonic responsiveness to CMS.
authors.affiliation: Department of Biomedicine, Section of Physiology, University of Bergen, Jonas Lies vei 91, N-5009 Bergen, Norway. janne.gronli@biomed.uib.no
authors.forename: Janne
authors.initials: J
authors.lastname: Grønli
authors.forename: Robert
authors.initials: R
authors.lastname: Murison
authors.forename: Eldbjørg
authors.initials: E
authors.lastname: Fiske
authors.forename: Bjørn
authors.initials: B
authors.lastname: Bjorvatn
authors.forename: Eli
authors.initials: E
authors.lastname: Sørensen
authors.forename: Chiara M
authors.initials: CM
authors.lastname: Portas
authors.forename: Reidun
authors.initials: R
authors.lastname: Ursin
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D002908:Chronic Disease; D003863:Depression / Q000209:etiology / Q000503:physiopathology / Q000523:psychology*; D004195:Disease Models, Animal; D004327:Drinking Behavior / Q000502:physiology; D005106:Exploratory Behavior / Q000502:physiology; D005260:Female; D005518:Food Preferences / Q000502:physiology / Q000523:psychology*; D008297:Male; D009043:Motor Activity / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012201:Reward; D012439:Saccharin; D012726:Sexual Behavior, Animal / Q000502:physiology*; D013315:Stress, Psychological / Q000150:complications / Q000503:physiopathology* / Q000523:psychology*; D013395:Sucrose; D013649:Taste / Q000502:physiology
chemical_list: D013395:Sucrose; D012439:Saccharin