title: Differential effects of photoperiod length on depression- and anxiety-like behavior in female and male diurnal spiny mice.
abstract: The relationships between biological rhythms and affective disorders are known but their underlying biology not clear. There is difficulty in studying circadian rhythms in humans and appropriate animal models are hard to identify or develop. Some studies show that diurnal rodents can be advantageous model animals for the study of interactions between biological rhythms and affective disorders but previous studies did not include females whereas in humans there are sex differences in affective disorders. The present study tested the effects of short photoperiods in both males and females of the diurnal golden spiny mouse (Acomys russatus). Adult, female and male spiny mice were housed in either neutral photoperiod (12:12 light/dark; NP), or short photoperiod (5:19 light/dark; SP) conditions. After 3weeks acclimatization, animals were tested for spontaneous activity in an open field, elevated plus maze (EPM), sweet solution preference (SSP) and the forced swim test (FST). Both sexes responded to the SP, but while SP males showed increased anxiety-like behavior in the EPM and depression-like behavior in the FST, females showed increased activity, reduced anxiety-like behavior in the EPM, depression-like response in the SSP and no effect in the FST. Differences between sexes were previously demonstrated in behavioral tests that followed a variety of manipulations, and were usually explained in the context of sex hormones. Yet, the current results cannot be compared with previous data from diurnal rodents and further testing of females from other diurnal rodents are needed to explore whether these differences are a general phenomenon or possibly unique to golden spiny mice.
authors.affiliation: Department of Zoology, Faculty of Life Sciences, Tel-Aviv University, Tel-Aviv 69978, Israel.
authors.forename: Miriam
authors.initials: M
authors.lastname: Ben-Hamo
authors.affiliation: Department of Zoology, Faculty of Life Sciences, Tel-Aviv University, Tel-Aviv 69978, Israel.
authors.forename: Katy
authors.initials: K
authors.lastname: Tal
authors.affiliation: Department of Zoology, Faculty of Life Sciences, Tel-Aviv University, Tel-Aviv 69978, Israel.
authors.forename: Rotem
authors.initials: R
authors.lastname: Paz-Cohen
authors.affiliation: Department of Zoology, Faculty of Life Sciences, Tel-Aviv University, Tel-Aviv 69978, Israel.
authors.forename: Noga
authors.initials: N
authors.lastname: Kronfeld-Schor
authors.affiliation: School of Behavioral Sciences, Tel-Aviv Yaffo Academic College, Tel-Aviv, Israel. Electronic address: haimh@mta.ac.il.
authors.forename: Haim
authors.initials: H
authors.lastname: Einat
mesh_terms: D000818:Animals; D001007:Anxiety / Q000503:physiopathology*; D002755:Choice Behavior / Q000502:physiology; D002940:Circadian Rhythm / Q000502:physiology*; D015331:Cohort Studies; D003863:Depression / Q000503:physiopathology*; D005260:Female; D008297:Male; D023421:Models, Animal; D009042:Motivation / Q000502:physiology; D009043:Motor Activity / Q000502:physiology; D051189:Murinae / Q000502:physiology*; D017440:Photoperiod; D011897:Random Allocation; D012201:Reward; D012439:Saccharin; D012727:Sex Characteristics; D055697:Taste Perception / Q000502:physiology
chemical_list: D012439:Saccharin
keywords: Animal model; Depression; Seasonal affective disorder; Sex difference