TY - JOUR
T1 - Influence of photoperiod and sex on locomotor behavior of meadow voles (Microtus pennsylvanicus) in an automated light-dark 'anxiety' test
AU - Ossenkopp, Klaus Peter
AU - Van Anders, Sari M.
AU - Engeland, Christopher G.
AU - Kavaliers, Martin
N1 - Funding Information:
This research and preparation of this manuscript were supported by Natural Sciences and Engineering Research Council of Canada (NSERC) operating and equipment grants to M. Kavaliers and K.-P. Ossenkopp. It was also made possible by equipment and software support from AccuScan Instruments (Columbus, OH). C.G. Engeland, who is now at the University of Illinois at Chicago, Department of Periodontics, was supported by an Ontario Graduate Scholarship and S.M. van Anders, who is now at Simon Fraser University, Department of Psychology, was supported by a NSERC of Canada USRA scholarship. We thank Shelley Cross-Mellor for technical assistance with the manuscript.
PY - 2005/10
Y1 - 2005/10
N2 - This study examined the influence of photoperiod on affective behavior (anxiety) of adult male and female meadow voles (Microtus pennsylvanicus), maintained in either a long or short day photoperiod, when tested in an automated (VersaMax) light-dark test. The light-dark test is based on an innate aversion of rodents to novel, brightly illuminated spaces and has been used with laboratory raised species, such as mice, to assess anxiety and/or fear related behaviors. Male and female meadow voles, housed either in a long day (LD: 16 h light) or short day (SD: 8 h light) photoperiod, were tested in the light-dark apparatus for 30 min on 3 consecutive days. All animals spent significantly (p<0.001) less time in the brightly lit chamber (900 lux) than in the dark chamber. LD voles, especially females, spent significantly less time in the brightly lit area than did SD voles. Both horizontal and vertical movements occurred less frequently per unit time in the dark area relative to the light, but only in the LD voles. LD female voles were the least active group in the dark area on the first test day but the most active group in the light area, despite spending the least amount of time in this area on the second and third test days. The present results show that LD voles exhibit more anxiety related behaviors in this test situation than do SD voles. LD females avoided the brightly lit area the most, particularly when the apparatus was novel. Thus, both photoperiod and sex influence situation-based anxiety in this species. These findings suggest that meadow voles are an excellent animal model in which to examine the role of gonadal hormones, and their modulation of defence related neural systems, in the induction of anxiety.
AB - This study examined the influence of photoperiod on affective behavior (anxiety) of adult male and female meadow voles (Microtus pennsylvanicus), maintained in either a long or short day photoperiod, when tested in an automated (VersaMax) light-dark test. The light-dark test is based on an innate aversion of rodents to novel, brightly illuminated spaces and has been used with laboratory raised species, such as mice, to assess anxiety and/or fear related behaviors. Male and female meadow voles, housed either in a long day (LD: 16 h light) or short day (SD: 8 h light) photoperiod, were tested in the light-dark apparatus for 30 min on 3 consecutive days. All animals spent significantly (p<0.001) less time in the brightly lit chamber (900 lux) than in the dark chamber. LD voles, especially females, spent significantly less time in the brightly lit area than did SD voles. Both horizontal and vertical movements occurred less frequently per unit time in the dark area relative to the light, but only in the LD voles. LD female voles were the least active group in the dark area on the first test day but the most active group in the light area, despite spending the least amount of time in this area on the second and third test days. The present results show that LD voles exhibit more anxiety related behaviors in this test situation than do SD voles. LD females avoided the brightly lit area the most, particularly when the apparatus was novel. Thus, both photoperiod and sex influence situation-based anxiety in this species. These findings suggest that meadow voles are an excellent animal model in which to examine the role of gonadal hormones, and their modulation of defence related neural systems, in the induction of anxiety.
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U2 - 10.1016/j.psyneuen.2005.05.001
DO - 10.1016/j.psyneuen.2005.05.001
M3 - Article
C2 - 15979243
AN - SCOPUS:22144446347
SN - 0306-4530
VL - 30
SP - 869
EP - 879
JO - Psychoneuroendocrinology
JF - Psychoneuroendocrinology
IS - 9
ER -
