Quantitative evaluation of gap junctions in rat brown adipose tissue after cold acclimation

Schneider-Picard, Gisela; Carpentier, Jean‐Louis; Girardier, L

doi:10.1007/bf01869196

Cited by 15 publications

(8 citation statements)

References 26 publications

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“…Although not directly demonstrated here, it is most likely that the postnatal increase in thermogenin mRNA in rat pups is also mediated via noradrenaline release from the sympathetic nervous system, and the cells at birth are thus apparently fully competent to respond to such stimulation. This is principally in agreement with the observation of Schneider-Picard & Girardier (1982) that sympathetic stimulation can evoke changes in flavoprotein redox state in pups younger than 12 h. As we see a tendency in cold-stressed pups to an increased level of thermogenin mRNA only 2 h after birth, the pups must be able to analyse the thermal environment directly at birth and respond accordingly. Thus, even at the moment of birth, the pup is not poikilothermic but initiates responses aimed at elevating metabolic heat production and stabilizing body temperature.…”

Section: Thermogenin Mrnasupporting

confidence: 92%

Postnatal recruitment of brown adipose tissue is induced by the cold stress experienced by the pups. An analysis of mRNA levels for thermogenin and lipoprotein lipase

Obregón¹,

Jacobsson²,

Kirchgessner

et al. 1989

Biochemical Journal

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In order to investigate the postnatal recruitment process, gene expression in the brown adipose tissue of rat pups was followed during the first 20 h of life. In normal pups, the level of mRNA coding for the uncoupling protein thermogenin increased markedly but gradually within the first 24 h. Lipoprotein lipase and actin mRNA levels were relatively low and remained constant. In pups exposed to thermoneutral temperature (35 degrees C) for the first 12 h after birth, no increase in thermogenin mRNA or lipoprotein lipase mRNA was observed, whereas in pups exposed to 28 degrees C a clear increase in both thermogenin and lipoprotein lipase mRNA levels was found. Actin mRNA levels were not affected by the environmental temperature under these circumstances. It was concluded that the postnatal recruitment in brown adipose tissue is a consequence of the cold stress experienced by the newborn pups. Thus, postnatal recruitment is not ontogenically predetermined.

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Section: Thermogenin Mrnasupporting

confidence: 92%

Postnatal recruitment of brown adipose tissue is induced by the cold stress experienced by the pups. An analysis of mRNA levels for thermogenin and lipoprotein lipase

Obregón¹,

Jacobsson²,

Kirchgessner

et al. 1989

Biochemical Journal

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“…We conclude that the membrane potential was relatively uniform over the region from which the redox states of the flavoproteins were measured. This is consistent with the observation that brown adipocytes are coupled (Revel, Yee & Hudspeth, 1971;Sheridan, 1971) and gap junctions present in appreciable amount (Schneider-Picard, Carpentier & Orci, 1980). Original records were usually accurately traced and then reduced in size with a photocopying machine (Figs.…”

Section: Introductionsupporting

confidence: 86%

Alpha and beta‐adrenergic mediation of membrane potential changes and metabolism in rat brown adipose tissue.

Girardier¹,

Schneider-Picard²

1983

The Journal of Physiology

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SUMMARY1. Membrane potential and flavoprotein redox state have been measured simultaneously and continuously in brown adipose tissue in order to determine how nerve stimulation and adrenergic agonists control its metabolic activity.2. Both trains of nerve impulses and addition of noradrenaline evoke two temporally distinct cell depolarizations. The first rapid depolarization precedes the increase in flavoprotein reduction.3. With nerve stimulation, at the time of maximum flavoprotein reduction the cell has repolarized or hyperpolarized. The second slow depolarization follows flavoprotein reduction.4. Phentolamine, an a antagonist, selectively blocks the first depolarization, but not the flavoprotein reduction. However the time of maximum flavoprotein reduction is delayed.5. Propranolol, a ,3 antagonist, delays the first repolarization until the end of nerve stimulation and inhibits the transient hyperpolarization, second depolarization and flavoprotein reduction.6. Isoproterenol, a , agonist, or the fatty acid octanoate produce only a transient hyperpolarization and subsequent slow depolarization following flavoprotein reduction.7. Thus brown adipose tissue contains both a-and ,-adrenergic receptors. Stimulation of a receptors produces an early membrane depolarization. Stimulation of ,8 receptors leads to an increase in metabolic activity which then appears to produce slow changes in membrane potential.

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“…Other NPY-and THir nerve fibres reach the BAT via the peri-arterial plexus (Cannon et al 1986). Brown adipocytes are electrically coupled by gap junctions (Schneider-Picard et al 1980). Two arteries reach the lateral ends of the interscapular BAT, and two veins drain the blood in the middle plane.…”

Section: Lean 20°cmentioning

confidence: 99%

The adipose organ: morphological perspectives of adipose tissues

2001

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Anatomically, an organ is defined as a series of tissues which jointly perform one or more interconnected functions. The adipose organ qualifies for this definition as it is made up of two tissue types, the white and brown adipose tissues, which collaborate in partitioning the energy contained in lipids between thermogenesis and the other metabolic functions. In rats and mice the adipose organ consists of several subcutaneous and visceral depots. Some areas of these depots are brown and correspond to brown adipose tissue, while many are white and correspond to white adipose tissue. The number of brown adipocytes found in white areas varies with age, strain of animal and environmental conditions. Brown and white adipocyte precursors are morphologically dissimilar. Together with a rich vascular supply, brown areas receive abundant noradrenergic parenchymal innervation. The gross anatomy and histology of the organ vary considerably in different physiological (cold acclimation, warm acclimation, fasting) and pathological conditions such as obesity; many important genes, such as leptin and uncoupling protein-1, are also expressed very differently in the two cell types. These basic mechanisms should be taken into account when addressing the physiopathology of obesity and its treatment.

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Quantitative evaluation of gap junctions in rat brown adipose tissue after cold acclimation

Cited by 15 publications

References 26 publications

Postnatal recruitment of brown adipose tissue is induced by the cold stress experienced by the pups. An analysis of mRNA levels for thermogenin and lipoprotein lipase

Postnatal recruitment of brown adipose tissue is induced by the cold stress experienced by the pups. An analysis of mRNA levels for thermogenin and lipoprotein lipase

Alpha and beta‐adrenergic mediation of membrane potential changes and metabolism in rat brown adipose tissue.

The adipose organ: morphological perspectives of adipose tissues

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