title: Increased brain and plasma oxytocin after nasal and peripheral administration in rats and mice.
abstract: The possibility to improve socio-emotional behaviors in humans by intranasal administration of synthetic oxytocin (OXT) attracts increasing attention, but its uptake into the brain has never been demonstrated so far. Here we used simultaneous microdialysis in both the dorsal hippocampus and amygdala of rats and mice in combination with concomitant blood sampling from the jugular vein to study the dynamics of the neuropeptide in brain extracellular fluid and plasma after its nasal administration. OXT was found to be increased in microdialysates from both the hippocampus and amygdala with peak levels occurring 30-60min after nasal administration. Despite a similar temporal profile of OXT concentrations in plasma, peripheral OXT is unlikely to contribute to dialysate OXT as calculated from in vitro recovery data, indicating a central route of transport. Moreover, intraperitoneal administration of synthetic OXT in identical amounts caused rapid peak levels in brain dialysates and plasma during the first 30min after treatment and a subsequent return toward baseline. While the precise route(s) of central transport remain to be elucidated, our data provide the first evidence that nasally applied OXT indeed reaches behaviorally relevant brain areas, and this uptake is paralleled by changes in plasma OXT.
authors.affiliation: Department of Behavioral and Molecular Neuroscience, University of Regensburg, 93053 Regensburg, Germany. Electronic address: inga.neumann@biologie.uni-regensburg.de.
authors.forename: Inga D
authors.initials: ID
authors.lastname: Neumann
authors.forename: Rodrigue
authors.initials: R
authors.lastname: Maloumby
authors.forename: Daniela I
authors.initials: DI
authors.lastname: Beiderbeck
authors.forename: Michael
authors.initials: M
authors.lastname: Lukas
authors.forename: Rainer
authors.initials: R
authors.lastname: Landgraf
mesh_terms: D000281:Administration, Intranasal; D061605:Administration, Intravenous; D000679:Amygdala / Q000378:metabolism; D000818:Animals; D001921:Brain / Q000378:metabolism*; D006624:Hippocampus / Q000378:metabolism; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D017551:Microdialysis; D010121:Oxytocin / Q000008:administration & dosage* / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D014018:Tissue Distribution
chemical_list: D010121:Oxytocin
keywords: Amygdala; Blood–brain barrier; Hippocampus; Intraperitonal; Nasal; Oxytocin