FIG. 18.

Study of the interscapular brown adipose tissue (iBAT) thermal response to norepinephrine (NE) infusion. (A, B) A rat (or mouse) is anesthetized, and the iBAT pad is exposed through a surgical incision. A thermistor is placed under the iBAT pad and secured with a stitch; a rectal thermistor is inserted in the colon for measurement of core temperature (not shown). The right jugular vein is cannulated and connected to an infusion pump for infusion of catecholamines or other molecules. Temperatures are measured continuously before and during infusion. Courtesy of Dr. Miriam O. Ribeiro. (C) Plasma NE levels during infusion in intact and Tx rats; (D) iBAT temperature during infusion in intact and Tx rats. Infusion lasted for 60 minutes, and the temperature data points indicate the difference between baseline and maximum peak achieved during infusion. Reproduced with permission from Ribeiro et al. (627).