title: Neuromedin U facilitates oxytocin release from the pituitary via beta adrenoceptors.
abstract: Neuromedin U activates noradrenergic neurones in the medulla oblongata and oxytocin neurones in the hypothalamus. Here we examined roles of noradrenergic transmission in oxytocin release from the pituitary after intracerebroventricular administration of neuromedin U in rats. Neuromedin U administration facilitated noradrenaline release in the supraoptic nucleus. Administration of a beta1 adrenoceptor antagonist, metoprolol, or a beta2 antagonist, ICI 118551 but not an alpha1 antagonist, benoxathian, reduced increases in plasma oxytocin concentrations observed after administration of neuromedin U, but plasma ACTH concentrations were not significantly changed. All theses data suggest that neuromedin U stimulates oxytocin release from the pituitary, at least in part, via activation of beta adrenoceptors.
authors.affiliation: Department of Medicine, Jichi Medical School, Tochigi-ken, Japan.
authors.forename: Kumiko
authors.initials: K
authors.lastname: Rokkaku
authors.forename: Tatsushi
authors.initials: T
authors.lastname: Onaka
authors.forename: Nobukazu
authors.initials: N
authors.lastname: Okada
authors.forename: Junichi
authors.initials: J
authors.lastname: Ideno
authors.forename: Akio
authors.initials: A
authors.lastname: Kawakami
authors.forename: Kazufumi
authors.initials: K
authors.lastname: Honda
authors.forename: Toshihiko
authors.initials: T
authors.lastname: Yada
authors.forename: Shun
authors.initials: S
authors.lastname: Ishibashi
mesh_terms: D000319:Adrenergic beta-Antagonists / Q000494:pharmacology; D000324:Adrenocorticotropic Hormone / Q000097:blood; D000818:Animals; D007276:Injections, Intraventricular; D008297:Male; D008790:Metoprolol / Q000494:pharmacology; D017551:Microdialysis; D009479:Neuropeptides / Q000494:pharmacology*; D010121:Oxytocin / Q000097:blood / Q000378:metabolism*; D010902:Pituitary Gland / Q000187:drug effects / Q000378:metabolism*; D011412:Propanolamines; D011863:Radioimmunoassay; D051381:Rats; D017208:Rats, Wistar; D011943:Receptors, Adrenergic, beta / Q000187:drug effects / Q000378:metabolism*
chemical_list: D000319:Adrenergic beta-Antagonists; D009479:Neuropeptides; D011412:Propanolamines; D011943:Receptors, Adrenergic, beta; C056900:neuromedin U; C026777:ICI 118551; D010121:Oxytocin; D000324:Adrenocorticotropic Hormone; D008790:Metoprolol