title: The role of orexin-1 receptors in physiologic responses evoked by microinjection of PgE2 or muscimol into the medial preoptic area.
abstract: The medial preoptic area (mPOA) of the hypothalamus has long been thought to play an important role in both fever production and thermoregulation. Microinjections of prostaglandin E2 (PgE2) or the GABA(A) agonist muscimol into the mPOA cause similar increases in body temperature, heart rate, and blood pressure. Microinjections of these compounds however evoke different behavioral responses with muscimol increasing and PgE2 having no effect on locomotion. The purpose of this study was to determine the role of orexin-1 receptors in mediating these dissimilar responses. Systemic injections of the orexin-1 receptor antagonist SB-334867 reduced temperature and cardiovascular responses produced by microinjections of muscimol, but had no effect on either response produced by PgE2. SB-334867 did not significantly decrease locomotion evoked by microinjections of muscimol into the mPOA. These data suggest that there are two central nervous system circuits involved in increasing body temperature, heart rate and blood pressure: one circuit activated by muscimol, involving orexin neurons, and a separate orexin-independent circuit activated by PgE2.
authors: Department of Emergency Medicine, Indiana University School of Medicine, Indianapolis, IN 46202, USA.
authors: Daniel E
authors: DE
authors: Rusyniak
authors: Dmitry V
authors: DV
authors: Zaretsky
authors: Maria V
authors: MV
authors: Zaretskaia
authors: Joseph A
authors: JA
authors: DiMicco
references: Brain Res. 1999 Jun 12;831(1-2):248-53
references: 10412003
references: Am J Physiol Regul Integr Comp Physiol. 2004 Aug;287(2):R306-13
references: 15031132
references: Eur J Neurosci. 2005 Sep;22(5):1169-75
references: 16176359
references: Am J Physiol Regul Integr Comp Physiol. 2007 Jan;292(1):R382-7
references: 16902182
references: Proc Natl Acad Sci U S A. 1998 Jan 6;95(1):322-7
references: 9419374
references: Psychopharmacology (Berl). 2001 Jan 1;153(2):210-8
references: 11205421
references: Neurosci Lett. 2006 Apr 24;397(3):291-6
references: 16406311
references: Pflugers Arch. 2008 Aug;456(5):837-46
references: 18188586
references: J Physiol. 1995 Nov 1;488 ( Pt 3):779-87
references: 8576867
references: Neuroscience. 2005;135(2):627-38
references: 16125857
references: Brain Res. 2008 Sep 16;1230:107-14
references: 18662676
references: Exp Physiol. 2008 Jul;93(7):773-97
references: 18469069
references: Brain Behav Immun. 2009 Oct;23(7):926-30
references: 19328847
references: Am J Physiol. 1999 Dec;277(6):R1780-5
references: 10600926
references: Am J Physiol. 1994 Jan;266(1 Pt 2):R125-35
references: 8304533
references: Trends Neurosci. 2002 Mar;25(3):154-9
references: 11852148
references: J Comp Neurol. 2006 Feb 10;494(5):845-61
references: 16374809
references: Neuron. 2005 Apr 21;46(2):297-308
references: 15848807
references: Am J Physiol Regul Integr Comp Physiol. 2007 Jan;292(1):R127-36
references: 16931649
references: Brain Res. 2005 Jun 28;1048(1-2):32-40
references: 15913569
references: Brain Res Bull. 1996;39(6):391-9
references: 9138749
references: Acta Physiol (Oxf). 2010 Mar;198(3):313-24
references: 19889100
references: Neuroreport. 2004 May 19;15(7):1127-31
references: 15129159
references: J Neuroendocrinol. 2001 Jun;13(6):561-6
references: 11412343
references: Neuroreport. 2000 Jun 26;11(9):1977-80
references: 10884055
references: Brain Res. 2002 Feb 22;928(1-2):113-25
references: 11844478
references: Neurosci Lett. 2003 Apr 3;340(1):1-4
references: 12648744
references: Eur J Neurosci. 2005 Dec;22(12):3137-46
references: 16367780
references: Regul Pept. 2007 Mar 1;139(1-3):39-44
references: 17134769
references: Brain Res. 2008 Aug 21;1226:116-23
references: 18586013
references: Exp Biol Med (Maywood). 2001 May;226(5):468-76
references: 11393177
references: Brain Res. 2001 Aug 3;909(1-2):68-74
references: 11478922
references: J Pharmacol Exp Ther. 2007 Nov;323(2):477-87
references: 17702902
references: Am J Physiol Regul Integr Comp Physiol. 2010 Jan;298(1):R130-40
references: 19923355
references: Clin Infect Dis. 2000 Oct;31 Suppl 5:S157-61
references: 11113018
references: Brain Res. 2000 Aug 4;873(1):181-7
references: 10915829