title: Brown adipose tissue thermogenesis heats brain and body as part of the brain-coordinated ultradian basic rest-activity cycle.
abstract: Brown adipose tissue (BAT), body and brain temperatures, as well as behavioral activity, arterial pressure and heart rate, increase episodically during the waking (dark) phase of the circadian cycle in rats. Phase-linking of combinations of these ultradian (<24 h) events has previously been noted, but no synthesis of their overall interrelationships has emerged. We hypothesized that they are coordinated by brain central command, and that BAT thermogenesis, itself controlled by the brain, contributes to increases in brain and body temperature. We used chronically implanted instruments to measure combinations of bat, brain and body temperatures, behavioral activity, tail artery blood flow, and arterial pressure and heart rate, in conscious freely moving Sprague-Dawley rats during the 12-h dark active period. Ambient temperature was kept constant for any particular 24-h day, varying between 22 and 27 degrees C on different days. Increases in BAT temperature (> or = 0.5 degrees C) occurred in an irregular episodic manner every 94+/-43 min (mean+/-SD). Varying the temperature over a wider range (18-30 degrees C) on different days did not change the periodicity, and neither body nor brain temperature fell before BAT temperature episodic increases. These increases are thus unlikely to reflect thermoregulatory homeostasis. Episodic BAT thermogenesis still occurred in food-deprived rats. Behavioral activity, arterial pressure (18+/-5 mmHg every 98+/-49 min) and heart rate (86+/-31 beats/min) increased approximately 3 min before each increase in BAT temperature. Increases in BAT temperature (1.1+/-0.4 degrees C) were larger than corresponding increases in brain (0.8+/-0.4 degrees C) and body (0.6+/-0.3 degrees C) temperature and the BAT episodes commenced 2-3 min before body and brain episodes, suggesting that BAT thermogenesis warms body and brain. Hippocampal 5-8 Hz theta rhythm, indicating active engagement with the environment, increased before the behavioral and autonomic events, suggesting coordination by brain central command as part of the 1-2 h ultradian basic rest-activity cycle (BRAC) proposed by Kleitman.
authors.affiliation: Departments of Physiology and Medicine, Centre for Neuroscience, Flinders University, Adelaide 5042, SA, Australia.
authors.forename: Y
authors.initials: Y
authors.lastname: Ootsuka
authors.forename: R C
authors.initials: RC
authors.lastname: de Menezes
authors.forename: D V
authors.initials: DV
authors.lastname: Zaretsky
authors.forename: A
authors.initials: A
authors.lastname: Alimoradian
authors.forename: J
authors.initials: J
authors.lastname: Hunt
authors.forename: A
authors.initials: A
authors.lastname: Stefanidis
authors.forename: B J
authors.initials: BJ
authors.lastname: Oldfield
authors.forename: W W
authors.initials: WW
authors.lastname: Blessing
mesh_terms: D002001:Adipose Tissue, Brown / Q000502:physiology*; D000818:Animals; D001522:Behavior, Animal / Q000502:physiology; D001794:Blood Pressure / Q000502:physiology; D001831:Body Temperature; D001833:Body Temperature Regulation / Q000502:physiology; D001921:Brain / Q000502:physiology*; D002940:Circadian Rhythm / Q000502:physiology*; D005260:Female; D005508:Food Deprivation / Q000502:physiology; D006339:Heart Rate / Q000502:physiology; D006624:Hippocampus / Q000502:physiology; D008297:Male; D010507:Periodicity; D051381:Rats; D017207:Rats, Sprague-Dawley; D012039:Regional Blood Flow / Q000502:physiology; D012146:Rest / Q000502:physiology; D022722:Thermogenesis / Q000502:physiology*; D013826:Theta Rhythm
references.citation: Neurosci Biobehav Rev. 1992 Fall;16(3):379-97
references.pmid: 1528526
references.citation: Science. 1965 Nov 12;150(3698):912-3
references.pmid: 5835794
references.citation: Nature. 1978 Mar 9;272(5649):164-6
references.pmid: 415252
references.citation: J Comp Neurol. 2003 Jun 2;460(3):303-26
references.pmid: 12692852
references.citation: Brain Res Brain Res Rev. 2005 Dec 1;50(1):27-56
references.pmid: 15890410
references.citation: Am J Physiol. 1984 May;246(5 Pt 2):R817-24
references.pmid: 6721001
references.citation: Behav Cogn Neurosci Rev. 2004 Sep;3(3):173-200
references.pmid: 15653814
references.citation: Physiol Rev. 2003 Oct;83(4):1153-81
references.pmid: 14506303
references.citation: J Physiol. 1995 Nov 1;488 ( Pt 3):779-87
references.pmid: 8576867
references.citation: Proc Soc Exp Biol Med. 1995 Feb;208(2):159-69
references.pmid: 7831348
references.citation: Diabetes. 2009 Jul;58(7):1526-31
references.pmid: 19401428
references.citation: Fed Proc. 1970 Jul-Aug;29(4):1541-52
references.pmid: 5459903
references.citation: Am J Physiol. 1999 Jun;276(6):R1569-78
references.pmid: 10362733
references.citation: Neuroscience. 2002;110(3):515-26
references.pmid: 11906790
references.citation: Annu Rev Physiol. 2004;66:275-89
references.pmid: 14977404
references.citation: Brain Res. 1996 Mar 11;712(1):53-9
references.pmid: 8705307
references.citation: Nature. 2005 Oct 27;437(7063):1257-63
references.pmid: 16251950
references.citation: Hum Neurobiol. 1982;1(3):195-204
references.pmid: 7185792
references.citation: Circ Res. 1979 May;44(5):692-700
references.pmid: 428065
references.citation: Physiol Behav. 1998 Dec 1;65(3):457-63
references.pmid: 9877411
references.citation: Nature. 1979 Sep 6;281(5726):31-5
references.pmid: 551265
references.citation: J Biol Rhythms. 1992 Winter;7(4):341-52
references.pmid: 1286205
references.citation: Neuroscience. 2008 Jul 17;154(4):1619-26
references.pmid: 18534763
references.citation: Physiol Rev. 2004 Jan;84(1):277-359
references.pmid: 14715917
references.citation: Neuroscience. 2006 Sep 15;141(4):2067-73
references.pmid: 16814930
references.citation: J Neurosci. 2006 Jan 4;26(1):241-5
references.pmid: 16399693
references.citation: Physiol Behav. 1983 Oct;31(4):417-27
references.pmid: 6657763
references.citation: Biol Bull. 1966 Aug;131(1):94-103
references.pmid: 5943781
references.citation: Science. 1967 Sep 29;157(3796):1586-8
references.pmid: 5341451
references.citation: J Neurosci. 2001 Jul 1;21(13):4864-74
references.pmid: 11425913
references.citation: Sleep. 1982;5(4):311-7
references.pmid: 6819628
references.citation: Jpn J Physiol. 1978;28(2):159-69
references.pmid: 691862
references.citation: Am J Physiol Regul Integr Comp Physiol. 2005 Sep;289(3):R827-38
references.pmid: 15860650
references.citation: N Engl J Med. 2009 Apr 9;360(15):1500-8
references.pmid: 19357405
references.citation: Ann N Y Acad Sci. 2008;1129:275-86
references.pmid: 18591488
references.citation: J Neurosci Methods. 2001 Jan 15;104(2):209-13
references.pmid: 11164247
references.citation: Am J Physiol. 1995 Nov;269(5 Pt 2):R1230-9
references.pmid: 7503315
references.citation: Physiol Behav. 1994 Oct;56(4):829-31
references.pmid: 7800756
references.citation: Pflugers Arch. 1992 Apr;420(5-6):500-7
references.pmid: 1614823
references.citation: News Physiol Sci. 2004 Apr;19:67-74
references.pmid: 15016906
references.citation: Electroencephalogr Clin Neurophysiol. 1986 Mar;63(3):289-95
references.pmid: 2419086
references.citation: J Neurosci. 1996 May 1;16(9):3056-66
references.pmid: 8622135
references.citation: Am J Physiol Endocrinol Metab. 2007 Aug;293(2):E444-52
references.pmid: 17473055
references.citation: Prog Neurobiol. 1986;26(1):1-54
references.pmid: 2870537
references.citation: Science. 2008 May 23;320(5879):1074-7
references.pmid: 18497298
references.citation: Pflugers Arch. 1990 Nov;417(3):336-41
references.pmid: 2274418
references.citation: Biol Rev Camb Philos Soc. 1991 Aug;66(3):275-99
references.pmid: 1932467
references.citation: Comp Biochem Physiol A Comp Physiol. 1990;96(1):1-11
references.pmid: 1975528
references.citation: Am J Physiol. 1968 Aug;215(2):389-403
references.pmid: 4969787
references.citation: J Appl Physiol. 1973 Apr;34(4):467-70
references.pmid: 4698602
references.citation: Endocrinology. 1981 Nov;109(5):1781-3
references.pmid: 7297505
references.citation: Physiol Behav. 1978 Dec;21(6):929-33
references.pmid: 552084
references.citation: Am J Physiol. 1995 Jan;268(1 Pt 2):R253-65
references.pmid: 7840329
references.citation: Respir Physiol Neurobiol. 2004 Aug 12;141(3):317-29
references.pmid: 15288602
references.citation: Exp Physiol. 1993 Mar;78(2):243-53
references.pmid: 8471243
references.citation: Nat Neurosci. 2008 Jan;11(1):62-71
references.pmid: 18084288
references.citation: Physiol Behav. 1987;39(4):513-9
references.pmid: 3575499
references.citation: Brain Res. 1969 Dec;16(2):417-40
references.pmid: 4311724
references.citation: Experientia. 1976 Sep 15;32(9):1165-7
references.pmid: 971750