Blood flow to the brown adipose tissue of conscious young rabbits during hypoxia in cold and warm conditions

1999 ◽  
Vol 437 (2) ◽  
pp. 255-260 ◽  
Author(s):  
J. P. Mortola ◽  
Daniele Merazzi ◽  
Lina Naso
Life Sciences ◽  
1994 ◽  
Vol 54 (1) ◽  
pp. 17-25 ◽  
Author(s):  
Tomoaki Nagashima ◽  
Hiroshi Ohinata ◽  
Akihiro Kuroshima

2011 ◽  
Vol 301 (4) ◽  
pp. R987-R994 ◽  
Author(s):  
Youichirou Ootsuka ◽  
Keerthi Kulasekara ◽  
Rodrigo Cunha de Menezes ◽  
William W. Blessing

Brown adipose tissue (BAT) thermogenesis occurs episodically in an ultradian manner approximately every 80–100 min during the waking phase of the circadian cycle, together with highly correlated increases in brain and body temperatures, suggesting that BAT thermogenesis contributes to brain and body temperature increases. We investigated this in conscious Sprague-Dawley rats by determining whether inhibition of BAT thermogenesis via blockade of beta-3 adrenoceptors with SR59230A interrupts ultradian episodic increases in brain and body temperatures and whether SR59230A acts on BAT itself or via sympathetic neural control of BAT. Interscapular BAT (iBAT), brain, and body temperatures, tail artery blood flow, and heart rate were measured in unrestrained rats. SR59230A (1, 5, or 10 mg/kg ip), but not vehicle, decreased iBAT, body, and brain temperatures in a dose-dependent fashion (log-linear regression P < 0.01, R2 = 0.3, 0.4, and 0.4, respectively, n = 10). Ultradian increases in BAT, brain, and body temperature were interrupted by administration of SR59230A (10 mg/kg ip) compared with vehicle, resuming after 162 ± 24 min (means ± SE, n = 10). SR59230A (10 mg/kg ip) caused a transient bradycardia without any increase in tail artery blood flow. In anesthetized rats, SR59230A reduced cooling-induced increases in iBAT temperature without affecting cooling-induced increases in iBAT sympathetic nerve discharge. Inhibition of BAT thermogenesis by SR59230A, thus, reflects direct blockade of beta-3 adrenoceptors in BAT. Interruption of episodic ultradian increases in body and brain temperature by SR59230A suggests that BAT thermogenesis makes a substantial contribution to these increases.


1980 ◽  
Vol 58 (8) ◽  
pp. 915-924 ◽  
Author(s):  
David O. Foster ◽  
Florent Depocas ◽  
M. Lorraine Frydman

Barbital-sedated, warm-acclimated (WA) or cold-acclimated (CA) rats were infused intravenously with noradrenaline (NA) at doses that elicited graded calorigenic responses. Blood flow (Q) to the various bodies of brown adipose tissue (BAT), the major sites of the NA-induced calorigenesis, was measured with labeled microspheres. The O2 content of arterial blood and of venous blood from interscapular BAT and the concentration of NA in arterial plasma (ANA) were also determined. ANA was linearly related to the dose of NA. Calorigenic response and the Q of total BAT and of separate bodies of BAT were sigmoid functions of ANA. The threshold for calorigenic response or for increased flow to BAT was an ANA of about 2 ng/mL (12 nM), except for some bodies of BAT in CA rats where it was closer to 4 ng/mL. Delivery of O2 to total BAT and calorigenic response were related linearly. The bodies of BAT were heterogeneous in Q per gram and in CA rats the hierarchy in Q per gram changed markedly as ANA and calorigenic response increased. The analysis of these results takes into account that calorigenesis in BAT normally is not mediated by circulating NA, that in NA-infused rats neuronal and extraneuronal uptakes of NA would effect a lower concentration of NA at the adrenoceptors of BAT than in the circulation, and that many factors such as organization and density of adrenergic innervation and the number and efficacy of receptors must have contributed to determining the measured responses of BAT. It is concluded that the differently located bodies of BAT in rats may have significant differences in composition and structure and that they may undergo differential development during cold acclimation.


Sign in / Sign up

Export Citation Format

Share Document