title: Regional c-Fos expression induced by peripheral oxytocin administration is prevented by the vasopressin 1A receptor antagonist SR49059.
abstract: Peripherally administered oxytocin induces a wide range of behavioural and physiological effects that are thought to be mediated by the oxytocin receptor (OTR). However, oxytocin also has considerable affinity for the vasopressin 1A receptor (V1AR), such that various oxytocinergic effects may in fact be mediated by the V1AR rather than the OTR. Here we used c-Fos immunohistochemistry to determine the extent to which the regional pattern of neuronal activation produced by peripheral oxytocin involves the V1AR. Male Wistar rats were administered oxytocin (1mg/kg, IP) alone, or following pre-treatment with the V1AR antagonist SR49059 (1mg/kg, IP), and were assessed for locomotor activity changes and for c-Fos expression across a number of brain regions. Oxytocin reduced the distance travelled by rats during a 70min test session, and this inhibitory behavioural effect was prevented by SR49059. Consistent with previous reports, oxytocin increased c-Fos expression in a number of brain regions. In several of these regions-the supraoptic and paraventricular (PVN) nuclei of the hypothalamus, locus coeruleus and nucleus of the solitary tract-the c-Fos response was prevented by SR49059 pre-treatment. Notably, SR49059 inhibited the c-Fos activation in oxytocin-synthesising magnocellular neurons in the PVN. However, c-Fos expression in the central amygdala to oxytocin was unaffected by SR49059. The current findings add to an increasing body of research suggesting that many of the functional effects of oxytocin may be V1AR mediated.
authors.affiliation: School of Psychology, Brennan MacCallum Building, University of Sydney, NSW 2006, Australia. Electronic address: chicks0333@gmail.com.
authors.forename: Callum
authors.initials: C
authors.lastname: Hicks
authors.affiliation: School of Psychology, Brennan MacCallum Building, University of Sydney, NSW 2006, Australia. Electronic address: lramos1984@gmail.com.
authors.forename: Linnet
authors.initials: L
authors.lastname: Ramos
authors.affiliation: School of Medical Sciences, University of New South Wales, NSW 2052, Australia. Electronic address: b.dampney@unsw.edu.au.
authors.forename: Bruno
authors.initials: B
authors.lastname: Dampney
authors.affiliation: School of Psychology, Brennan MacCallum Building, University of Sydney, NSW 2006, Australia. Electronic address: Sarah.Baracz@sydney.edu.au.
authors.forename: Sarah J
authors.initials: SJ
authors.lastname: Baracz
authors.affiliation: School of Psychology, Brennan MacCallum Building, University of Sydney, NSW 2006, Australia. Electronic address: Iain.McGregor@sydney.edu.au.
authors.forename: Iain S
authors.initials: IS
authors.lastname: McGregor
authors.affiliation: Discipline of Psychiatry, Sydney Medical School, University of Sydney, Concord Hospital, NSW 2139, Australia. Electronic address: glenn.hunt@sydney.edu.au.
authors.forename: Glenn E
authors.initials: GE
authors.lastname: Hunt
mesh_terms: D000818:Animals; D065092:Antidiuretic Hormone Receptor Antagonists / Q000494:pharmacology*; D001933:Brain Stem / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D002491:Central Nervous System Agents / Q000494:pharmacology*; D007031:Hypothalamus / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D007150:Immunohistochemistry; D007211:Indoles / Q000494:pharmacology*; D008297:Male; D009043:Motor Activity / Q000187:drug effects / Q000502:physiology; D009474:Neurons / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D010121:Oxytocin / Q000378:metabolism / Q000494:pharmacology*; D016760:Proto-Oncogene Proteins c-fos / Q000378:metabolism*; D011759:Pyrrolidines / Q000494:pharmacology*; D011897:Random Allocation; D017208:Rats, Wistar; D017483:Receptors, Vasopressin / Q000378:metabolism*
chemical_list: D065092:Antidiuretic Hormone Receptor Antagonists; D002491:Central Nervous System Agents; D007211:Indoles; D016760:Proto-Oncogene Proteins c-fos; D011759:Pyrrolidines; D017483:Receptors, Vasopressin; D010121:Oxytocin; C082134:relcovaptan
keywords: Hypothalamus; Locomotor activity; Oxytocin; SR49059; Vasopressin 1A receptor; c-Fos