Hypothalamic control of brown adipose tissue in Zucker lean and obese rats. Effect of electrical stimulation of the ventromedial nucleus and other hypothalamic centres.
Electrophysiological stimulation of the hypothalamic ventromedial nucleus (VMN) resulted in an increase in interscapular brown adipose tissue (BAT) temperature in both lean and obese (fa/fa) rats. Graded stimulations resulted in progressively larger temperature increases in both lean and obese (fa/fa) groups. Both intraperitoneal injection of propranolol and surgical denervation (but not sham denervation) abolished the increase in BAT temperature following VMN stimulation, in both lean and obese (fa/fa) groups. Electrical stimulation of the supraoptic region, and certain anterior hypothalamic regions also resulted in increases in BAT temperature of lean and obese (fa/fa) rats, but stimulation of the dorsomedial nucleus and regions of the lateral hypothalamus did not affect BAT temperature. All hypothalamic regions capable of activating BAT gave a similar maximum rise in temperature for a given stimulus in lean and obese (fa/fa) rats. These results suggest that the efferent sympathetic pathway from the VMN and other hypothalamic regions of BAT is normal in the obese (fa/fa) rat.
D002001:Adipose Tissue, Brown / Q000502:physiology* / Q000503:physiopathology; D000818:Animals; D001831:Body Temperature / Q000187:drug effects; D004525:Efferent Pathways / Q000502:physiology / Q000503:physiopathology; D004558:Electric Stimulation; D005260:Female; D007031:Hypothalamus / Q000502:physiology* / Q000503:physiopathology; D009765:Obesity / Q000503:physiopathology*; D011433:Propranolol / Q000494:pharmacology; D051381:Rats; D011924:Rats, Zucker; D013495:Supraoptic Nucleus / Q000502:physiology / Q000503:physiopathology; D014697:Ventromedial Hypothalamic Nucleus / Q000502:physiology / Q000503:physiopathology
D011433:Propranolol