title: Stanniocalcin-1 in the subfornical organ inhibits the dipsogenic response to angiotensin II.
abstract: Recently, receptors for the calcium-regulating glycoprotein hormone stanniocalcin-1 (STC-1) have been found within subfornical organ (SFO), a central structure involved in the regulation of electrolyte and body fluid homeostasis. However, whether SFO neurons produce STC-1 and how STC-1 may function in fluid homeostasis are not known. Two series of experiments were done in Sprague-Dawley rats to investigate whether STC-1 is expressed within SFO and whether it exerts an effect on water intake. In the first series, experiments were done to determine whether STC-1 was expressed within cells in SFO using immunohistochemistry, and whether protein and gene expression for STC-1 existed in SFO using Western blot and quantitative RT-PCR, respectively. Cells containing STC-1 immunoreactivity were found throughout the rostrocaudal extent of SFO. STC-1 protein expression within SFO was confirmed with Western blot, and SFO was also found to express STC-1 mRNA. In the second series, microinjections (200 nl) of STC-1, ANG II, a combination of the two or the vehicle were made into SFO in conscious, unrestrained rats. Water intake was measured at 0700 for a 1-h period after each injection in animals. Microinjections of STC-1 (17.6 or 176 nM) alone had no effect on water intake compared with controls. However, STC-1 not only attenuated the drinking responses to ANG II for about 30 min, but also decreased the total water intake over the 1-h period. These data suggest that STC-1 within the SFO may act in a paracrine/autocrine manner to modulate the neuronal responses to blood-borne ANG II. These findings also provide the first direct evidence of a physiological role for STC-1 in central regulation of body fluid homeostasis.
authors.affiliation: Dept. of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, Univ. of Western Ontario, London, Ontario, Canada, N6A 5C1. john.ciriello@schulich.uwo.ca
authors.forename: Jason M
authors.initials: JM
authors.lastname: Moreau
authors.forename: Waseem
authors.initials: W
authors.lastname: Iqbal
authors.forename: Jeffrey K
authors.initials: JK
authors.lastname: Turner
authors.forename: Graham F
authors.initials: GF
authors.lastname: Wagner
authors.forename: John
authors.initials: J
authors.lastname: Ciriello
mesh_terms: D000804:Angiotensin II / Q000008:administration & dosage / Q000494:pharmacology*; D000818:Animals; D004326:Drinking / Q000187:drug effects* / Q000502:physiology; D006023:Glycoproteins / Q000008:administration & dosage / Q000494:pharmacology* / Q000502:physiology*; D006706:Homeostasis / Q000187:drug effects / Q000502:physiology; D008297:Male; D008845:Microinjections; D023421:Models, Animal; D051381:Rats; D017207:Rats, Sprague-Dawley; D013356:Subfornical Organ / Q000166:cytology / Q000502:physiology*; D014882:Water-Electrolyte Balance / Q000187:drug effects / Q000502:physiology
chemical_list: D006023:Glycoproteins; D000804:Angiotensin II; C051795:teleocalcin