Criteria for differentiation of brown and white fat in the rat

Abstract

By using a modified method of Falck, the distribution of nerves containing catecholamines in brown and white fat was studied. The brown fat cells had sympathetic nerve fibers with synaptic varicosities running between all cells. White fat had no sympathetic innervation of the parenchymal cells. Both tissues contained a dense network of fibers around the arterial blood vessels.

Eosinophils and Type 2 Cytokine Signaling in Macrophages Orchestrate Development of Functional Beige Fat

“…As shown in Figure S5A, expression of TH protein was temperature responsive and inducible in all three adipose depots (BAT, scWAT, and eWAT). However, unlike BAT, basal expression of TH was nearly absent in scWAT and eWAT of mice housed at 22°C, but dramatically induced upon cold exposure (Figure S5A), findings that are consistent with published reports demonstrating the dense innervation of BAT but not scWAT and eWAT by the sympathetic nerves (Daniel and Derry, 1969; Morrison and Nakamura, 2011; Slavin and Ballard, 1978; Trayhurn and Ashwell, 1987). Since this change in TH expression correlated with alternative activation of scWAT macrophages (Figure S5A, S4E and 4E), we utilized intracellular flow cytometry to quantify TH protein content of scWAT macrophages.…”

“…While this model works well for tissues that are densely innervated by the sympathetic nerves (Morrison and Nakamura, 2011), such as the interscapular BAT, it does not explain how cold exposure results in the rapid remodeling of the poorly innervated scWAT (Daniel and Derry, 1969; Slavin and Ballard, 1978; Trayhurn and Ashwell, 1987). In these classic studies, adrenergic nerves only innervated 2-3% of all adipocytes in WAT, leading these authors to conclude that the sympathetic nerves primarily innervate blood vessels of the WAT (Daniel and Derry, 1969; Slavin and Ballard, 1978). These older observations thus suggest that the adrenergic tone of WAT must somehow be amplified during cold stress to stimulate biogenesis of beige fat.…”

Effects of Catecholamines on Metabolism

“…The growth of this tissue is also influenced by the sympathetic nervous system: the tissue actually grows when subjected to excessive stimulation (CAMERON and SMITH, 1964;SMITH and HORWITZ, 1969). The rich sympathetic innervation of this tissue is also unique in that it has a dual nature: cells and blood vessels are innervated by noradrenaline-containing nerves from different parts of the sympathetic nervous system (DERRY et al, 1969;DERRY and DANIEL, 1970;DANIEL and DERRY, 1969). Its vascularity is likewise very rich and the blood flow is increased by catecholamines (JANSKY and HART, 1968;HElM and HULL, 1966;KUROSHIMA et al, 1967).…”

A worm of one's own: how helminths modulate host adipose tissue function and metabolism

“…Similar to BAT, high expression of UCP1 in beige adipocytes allows energy to be dissipated as heat, sustaining BAT function during cold exposure [81,82]. By contrast, beige fat is poorly innervated by neurons [83,84], suggesting the possibility of alternate means of induction and maintenance. Given the ability of beige adipose tissue to literally ‘burn’ fat, there is considerable interest in understanding signals that both promote increased beige fat and activate beige fat thermogenesis.…”