Unilaterality of the sympathetic innervation of each pad of rat interscapular brown adipose tissue

1982 ◽  
Vol 60 (2) ◽  
pp. 107-113 ◽  
Author(s):  
David O. Foster ◽  
Florent Depocas ◽  
Gloria Zaror Behrens

The effects of sham, unilateral, and bilateral surgical denervation of rat interscapular brown adipose tissue (IBAT) on blood flow to the two IBAT pads of cold-acclimated (CA) rats during exposure of the animals to 22 or −6 °C and on the noradrenaline (NA) content and total dopamine-β-hydroxylase (DBH) (EC 1.14.17.1) activity of the pads in both warm-acclimated (WA) rats and CA rats were examined. Increase in IBAT blood flow upon cold exposure was taken as an index of sympathetically mediated calorigenesis in the tissue, and decreases in tissue levels of NA and DBH served as indices of the extent of destruction of the sympathetic innervation. At 24 h postsurgery, denervated pads of CA rats, whether from unilaterally or bilaterally denervated IBAT, had less than 3% of the NA, 40-44% of the DBH, and 0% of the 10-fold, cold-induced increase in blood flow measured in intact pads of CA rats with sham-operated or unilaterally denervated IBAT. IBAT bilaterally denervated for 24 h was as responsive in terms of its maximum increase in blood flow during infusion of CA rats with NA as intact IBAT. DBH in denervated pads of both WA rats and CA rats fell to 5% or less of control levels at 2 days postdenervation and remained at these low levels, as did NA, for at least 8 weeks. These results strongly support the longstanding but recently challenged hypothesis that each pad of rat IBAT is independently innervated by sympathetic fibers.

Author(s):  
Clara Huesing ◽  
Rui Zhang ◽  
Sanjeev Gummadi ◽  
Nathan Lee ◽  
Emily Qualls‐Creekmore ◽  
...  

1984 ◽  
Vol 247 (2) ◽  
pp. R290-R295 ◽  
Author(s):  
J. S. Fisler ◽  
T. Yoshida ◽  
G. A. Bray

Catecholamine turnover in response to fasting, cold exposure, and a high-fat diet has been measured in the Osborne-Mendel rat, which readily develops obesity when fed a high-fat diet, and the S 5B/P1 rat, which does not. We have tested the hypothesis that this difference in response to diet might be associated with altered rates of norepinephrine or epinephrine turnover. The endogenous norepinephrine concentration in interscapular brown adipose tissue was significantly greater in fasted S 5B/P1 rats than in fasted Osborne-Mendel rats. The fractional norepinephrine turnover rate in interscapular brown adipose tissue of fasted animals was also greater in the S 5B/P1 rat than in the Osborne-Mendel rat. Cold exposure increased the fractional norepinephrine turnover rate in interscapular brown adipose tissue for both strains of rats but increased the fractional norepinephrine turnover rate in the pancreas in only the Osborne-Mendel rats. The turnover of epinephrine and the adrenal concentration of this hormone were not different between the two strains. Normal and high-fat diets were fed to both strains; the Osborne-Mendel rats were pair fed the high-fat diet to prevent excess weight gain. Endogenous concentrations of norepinephrine in interscapular brown adipose tissue was increased by the high-fat diet; the increase was greater in S 5B/P1 rats. The high-fat diet resulted in increased norepinephrine turnover in interscapular brown adipose tissue of the S 5B/P1 rat but not the Osborne-Mendel rat.(ABSTRACT TRUNCATED AT 250 WORDS)


1984 ◽  
Vol 247 (2) ◽  
pp. E181-E189 ◽  
Author(s):  
L. Landsberg ◽  
M. E. Saville ◽  
J. B. Young

The sympathetic nervous system (SNS) plays a critical role in the regulation of mammalian thermogenic responses to cold exposure and dietary intake. Catecholamine-stimulated thermogenesis is mediated by the beta-adrenergic receptor. In the rat brown adipose tissue is the major site of metabolic heat production in response to both cold (nonshivering thermogenesis) and diet (diet-induced thermogenesis). Measurements of norepinephrine turnover rate in interscapular brown adipose tissue of the rat demonstrate increased sympathetic activity in response to both cold exposure and overfeeding. In adult humans, a physiologically significant role for brown adipose tissue has not been established but cannot be excluded. It appears likely that dietary changes in SNS activity are related, at least in part, to the changes in metabolic rate that occur in association with changes in dietary intake.


1999 ◽  
Vol 276 (1) ◽  
pp. R143-R151 ◽  
Author(s):  
Victoria L. King ◽  
Linda P. Dwoskin ◽  
Lisa A. Cassis

The neuronal uptake of norepinephrine (NE) in sympathetically innervated tissues is mediated by a high-affinity NE uptake transporter (NET). Rat interscapular brown adipose tissue (ISBAT) is densely innervated by the sympathetic nervous system for the control of cold- and diet-induced thermogenesis. To determine if cold exposure regulates the NET, kinetic parameters for [3H]NE uptake and [3H]nisoxetine (Nis) binding were determined in ISBAT from 7-day cold-exposed (CE) and control rats. Uptake of [3H]NE in ISBAT slices was of high affinity (1.6 μM). After 7 days of cold exposure the affinity for [3H]NE uptake was not altered; however, the uptake capacity was decreased (38%) in ISBAT slices from CE rats. Kinetic parameters for [3H]Nis binding demonstrated a single high-affinity site in ISBAT from CE and control rats with similar affinity. The density of [3H]Nis sites in ISBAT was decreased (38%) following cold exposure. A time course (2 h-7 days) for cold exposure demonstrated downregulation of [3H]Nis binding density by day 3, which remained through day 7. The affinity for [3H]Nis binding was transiently decreased at 2 h of cold exposure. Similarly, ISBAT NE content was decreased at 2 h of cold exposure. Pair feeding CE rats to food intake of controls normalized plasma NE content; however, [3H]Nis binding density in ISBAT remained decreased in pair-fed rats. These results demonstrate that the ISBAT NET is downregulated following cold exposure. Reductions in ISBAT NE content precede alterations in NET density; however, plasma NE content is not related to regulation of the NET.


1984 ◽  
Vol 62 (10) ◽  
pp. 1327-1332 ◽  
Author(s):  
Florent Depocas ◽  
David O. Foster ◽  
Gloria Zaror-Behrens ◽  
Suzanne Lacelle ◽  
B. Nadeau

Twenty-four hours after subcutaneous administration of 6-hydroxydopamine (6-OHDA) at a dose of 10 mg/kg body weight in warm-acclimated rats, noradrenaline (NA) content and dopamine β-hydroxylase (DBH) activity of interscapular brown adipose tissue (IBAT) were reduced to about 10 and 35% of control values. Corresponding values for cold-acclimated rats, similarly treated, were 12 and 32%. In both groups of animals, calorigenic function in IBAT assessed by measurement of the effect of cold exposure on rate of blood flow through the tissue was lost almost completely. Twenty-four hours after treatment of rats with various doses of 6-OHDA, calorigenesis in IBAT was directly related to residual NA. Measurements of noradrenaline content and DBH activity from 1 to 10 days after 6-OHDA and the increase in IBAT blood flow of cold-exposed animals from 1 to 7 days after 6-OHDA indicated marked differences in the extent to which each of these indicators of the integrity and function of sympathetic nerve endings recovered with time and with the acclimation temperature of the animals. Regeneration of macromolecuiar components of noradrenergic vesicles in IBAT appeared to occur more rapidly in cold than in warm-acclimated animals. Thus, moderate doses of 6-OHDA may acutely sympathectomize IBAT, but as previously reported for other tissues, full recovery of function of IBAT occurs long before noradrenaline stores are replenished.


Endocrinology ◽  
2003 ◽  
Vol 144 (11) ◽  
pp. 4831-4840 ◽  
Author(s):  
Márcio Pereira-da-Silva ◽  
Márcio A. Torsoni ◽  
Hugo V. Nourani ◽  
Viviane D. Augusto ◽  
Cláudio T. Souza ◽  
...  

Abstract Short-term cold exposure of homeothermic animals leads to higher thermogenesis and food consumption accompanied by weight loss. An analysis of cDNA-macroarray was employed to identify candidate mRNA species that encode proteins involved in thermogenic adaptation to cold. A cDNA-macroarray analysis, confirmed by RT-PCR, immunoblot, and RIA, revealed that the hypothalamic expression of melanin-concentrating hormone (MCH) is enhanced by exposure of rats to cold environment. The blockade of hypothalamic MCH expression by antisense MCH oligonucleotide in cold-exposed rats promoted no changes in feeding behavior and body temperature. However, MCH blockade led to a significant drop in body weight, which was accompanied by decreased liver glycogen, increased relative body fat, increased absolute and relative interscapular brown adipose tissue mass, increased uncoupling protein 1 expression in brown adipose tissue, and increased consumption of lean body mass. Thus, increased hypothalamic MCH expression in rats exposed to cold may participate in the process that allows for efficient use of energy for heat production during thermogenic adaptation to cold.


1980 ◽  
Vol 58 (10) ◽  
pp. 1212-1220 ◽  
Author(s):  
David O. Foster ◽  
Florent Depocas ◽  
Gloria Zaror-Behrens ◽  
M. Lorraine Frydman ◽  
Suzanne Lacelle

The rate of blood flow (Q) to interscapular brown adipose tissue (IBAT) and the arteriovenous difference in plasma noradrenaline (NA) across the tissue were measured in warm-acclimated (WA) or cold-acclimated (CA) rats during infusion of NA at doses of 1–12.5 ng min−1 g−0.74 (approximately 0.2–2.7 μg min−1 kg−1) and in the period of steady calorigenic response associated with steady concentration of NA in arterial plasma (ANA). ANA was linearly related to the dose of NA. Calorigenic response, percentage of cardiac output to IBAT, and Q per gram of IBAT were sigmoid functions of ANA and at their maxima were about 2.5 times greater in CA than in WA rats. The rate of uptake of NA by IBAT increased with ANA and Q, each of which had a major influence on rate, but the coefficient of extraction of NA by the tissue (ENAIBAT) declined. Measurements in rats given a dose of propranolol that partially inhibited the NA-induced increase in Q to IBAT indicated that the decline in ENAIBAT was attributable primarily to the increase in Q rather than to increasing saturation of uptake mechanisms. Diffusion-limited extraction of NA is the probable basis for the effect of Q on ENAIBAT. Possible implications of flow-dependent extraction of NA in studies involving measurements of the uptake of exogenous NA by tissues or organs are discussed.


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