title: Effects of orexin-monoaminergic interactions on oxytocin secretion in rat neurohypophyseal cell cultures.
abstract: The effects of orexin-monoaminergic compound interactions on oxytocin release were studied in 14-day rat neurohypophyseal cell cultures prepared by an enzymatic dissociation technique. The oxytocin contents of the supernatants were determined by radioimmunoassay. Following the administration of orexin-A or orexin-B in increasing doses, significant changes were not observed in the oxytocin content of the supernatant media. The oxytocin level increased substantially in response to adrenaline, noradrenaline, serotonin, histamine, dopamine or K(+) treatment. Preincubation with orexin-A or orexin-B reduced the adrenaline-, histamine- or serotonin-induced oxytocin level increases, but the oxytocin concentrations of the supernatant media remained above the control level. There was no significant difference in decreasing effect between orexin-A and orexin-B. Neither orexin-A nor orexin-B induced changes in oxytocin release following monoaminergic compound treatment. The results indicate that the changes in oxytocin secretion induced by the monoaminergic system can be directly influenced by the orexin system. The effects of orexin on oxytocin release can be antagonized by an orexin-1 receptor-specific antagonist. It may be presumed that the orexins can play a role in the pathogenetic process of metabolic diseases (e.g. obesity) by reducing the effects of increased oxytocin release caused by monoaminergic compounds. The interactions between the monoaminergic and orexin systems regarding oxytocin secretion occur at both the hypothalamic and the neurohypophyseal levels.
authors.affiliation: Department of Environmental Biology, Gyula Juhász Faculty of Education, University of Szeged, Szeged, Hungary.
authors.forename: Tímea
authors.initials: T
authors.lastname: Ocskó
authors.forename: Márta
authors.initials: M
authors.lastname: Gálfi
authors.forename: Mariann
authors.initials: M
authors.lastname: Radács
authors.forename: Zsolt
authors.initials: Z
authors.lastname: Molnár
authors.forename: Gyöngyi K
authors.initials: GK
authors.lastname: Kis
authors.forename: Kinga
authors.initials: K
authors.lastname: Rákosi
authors.forename: Andor H
authors.initials: AH
authors.lastname: Molnár
authors.forename: Ferenc
authors.initials: F
authors.lastname: László
authors.forename: Ferenc A
authors.initials: FA
authors.lastname: László
authors.forename: Csaba
authors.initials: C
authors.lastname: Varga
mesh_terms: D000316:Adrenergic alpha-Agonists / Q000494:pharmacology; D000818:Animals; D002478:Cells, Cultured; D004298:Dopamine / Q000494:pharmacology*; D004837:Epinephrine / Q000494:pharmacology*; D006632:Histamine / Q000494:pharmacology*; D017442:Histamine Agonists / Q000494:pharmacology; D047908:Intracellular Signaling Peptides and Proteins / Q000494:pharmacology*; D008297:Male; D009479:Neuropeptides / Q000494:pharmacology*; D000068797:Orexins; D010121:Oxytocin / Q000378:metabolism*; D010904:Pituitary Gland, Posterior / Q000166:cytology* / Q000187:drug effects*; D011188:Potassium / Q000494:pharmacology; D011863:Radioimmunoassay; D051381:Rats; D017208:Rats, Wistar; D012701:Serotonin / Q000494:pharmacology*; D017366:Serotonin Receptor Agonists / Q000494:pharmacology; D013566:Sympathomimetics / Q000494:pharmacology
chemical_list: D000316:Adrenergic alpha-Agonists; D017442:Histamine Agonists; D047908:Intracellular Signaling Peptides and Proteins; D009479:Neuropeptides; D000068797:Orexins; D017366:Serotonin Receptor Agonists; D013566:Sympathomimetics; D012701:Serotonin; D010121:Oxytocin; D006632:Histamine; D011188:Potassium; D004298:Dopamine; D004837:Epinephrine