title: Leptin activates oxytocin neurons of the hypothalamic paraventricular nucleus in both control and diet-induced obese rodents.
abstract: The adipocyte-derived hormone leptin acts in the brain to reduce body weight and fat mass. Recent studies suggest that parvocellular oxytocin (OXT) neurons of the hypothalamic paraventricular nucleus (PVN) can mediate body weight reduction through inhibition of food intake and increased energy expenditure. However, the role of OXT neurons of the PVN as a primary target of leptin has not been investigated. Here, we studied the potential role of OXT neurons of the PVN in leptin-mediated effects on body weight regulation in fasted rats. We demonstrated that intracerebroventricular (ICV) leptin activates STAT3 phosphorylation in OXT neurons of the PVN, showed that this occurs in a subpopulation of OXT neurons that innervate the nucleus of the solitary tract (NTS), and provided further evidence suggesting a role of OXT to mediate leptin's actions on body weight. In addition, our results indicated that OXT neurons are responsive to ICV leptin and mediate leptin effects on body weight in diet induced obese (DIO) rats, which are resistant to the anorectic effects of the hormone. Thus, we conclude that leptin targets a specific subpopulation of parvocellular OXT neurons of the PVN, and that this action may be important for leptin's ability to reduce body weight in both control and obese rats.
authors.affiliation: Laboratory of Neurophysiology, Argentine Research Council and Scientific Research Commission of the Province of Buenos Aires, La Plata, Buenos Aires, Argentina. marioperello@yahoo.com
authors.forename: Mario
authors.initials: M
authors.lastname: Perello
authors.forename: Jesica
authors.initials: J
authors.lastname: Raingo
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D001835:Body Weight / Q000187:drug effects* / Q000502:physiology; D017931:DNA Primers / Q000235:genetics; D020869:Gene Expression Profiling; D007150:Immunohistochemistry; D057967:Infusions, Intraventricular; D020738:Leptin / Q000494:pharmacology*; D008297:Male; D009474:Neurons / Q000378:metabolism*; D009765:Obesity / Q000378:metabolism*; D010121:Oxytocin / Q000378:metabolism*; D010286:Paraventricular Hypothalamic Nucleus / Q000166:cytology* / Q000378:metabolism; D010766:Phosphorylation / Q000187:drug effects; D051381:Rats; D017207:Rats, Sprague-Dawley; D050796:STAT3 Transcription Factor / Q000378:metabolism; D013266:Stilbamidines
chemical_list: C049774:2-hydroxy-4,4'-diamidinostilbene, methanesulfonate salt; D017931:DNA Primers; D020738:Leptin; D050796:STAT3 Transcription Factor; C494088:Stat3 protein, rat; D013266:Stilbamidines; D010121:Oxytocin