title: Steroid dependent effects of oxytocin on spontaneous motor activity in female rats.
abstract: In the present study, dose relationships for effects of oxytocin (OXY) on spontaneous motor activity in female rats were investigated. Ovariectomized (OVX) and cycling female Sprague-Dawley rats were given OXY 10-1000 microg/kg s.c. or saline, 10 min before registration of motor activity in an open-field arena. In the OVX rats, 100 microg/kg of OXY increased the activity in the center of the arena, whereas 1000 microg/kg decreased locomotor activity (LA). In the cycling rats, OXY 100-1000 microg/kg decreased LA during diestrus, while 1000 microg/kg also decreased LA during metestrus. The latter dose also reduced the exploratory behavior during estrus. In a second experiment, OVX rats were pretreated with estradiol benzoate (EB) and progesterone (P). When P levels were predominant, OXY 10-1000 microg/kg decreased LA. Oxytocin 10-100 microg/kg given after pretreatment with EB increased the activity in the center of the arena, whereas 1000 micro/kg given in the presence of both EB and P increased peripheral activity (PA). These results show that the effects of OXY on motor activity in female rats are modified by female sex steroid hormones.
authors.affiliation: Department of Molecular Medicine, Karolinska Hospital, Stockholm, Sweden. Maria.Petersson@fyfa.ki.se
authors.forename: M
authors.initials: M
authors.lastname: Petersson
authors.forename: S
authors.initials: S
authors.lastname: Ahlenius
authors.forename: U
authors.initials: U
authors.lastname: Wiberg
authors.forename: P
authors.initials: P
authors.lastname: Alster
authors.forename: K
authors.initials: K
authors.lastname: Uvnäs-Moberg
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D004305:Dose-Response Relationship, Drug; D004958:Estradiol / Q000494:pharmacology*; D004971:Estrus / Q000502:physiology*; D005260:Female; D009043:Motor Activity / Q000187:drug effects*; D010053:Ovary / Q000502:physiology; D010121:Oxytocin / Q000494:pharmacology*; D011374:Progesterone / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D011374:Progesterone; D004958:Estradiol; D010121:Oxytocin