Intrascapular brown adipose tissue (IBAT) temperature and blood flow responses following ventromedial hypothalamic stimulation to sham and IBAT-denervated rats

Intrascapular brown adipose tissue temperature (T_IBAT) and capillary blood flow along with colonic (T_c) and tail (T_t) temperatures as well as blood pressure and heart rate responses were measured simultaneously in groups of age-natched, anesthetised, sham control and IBAT-denervated Long-Evans rats following VNH electrical stimulation. Unilateral VMH electrical stimulation (0.5 ms pulses of 100 μA at 50 Hz for 30 s) evoked rises in T_IBAT (above core) and IBAT blood flow in the Long-Evans sham control group, along with increases in blood pressure and heart rate. Rises in IBAT temperature and capillary blood flow were absent in the surgical denervated group following VMH electrical stimulation whereas the evoked pressor and tachycardic responses were left intact and were similar to those responses seen in the sham control group. The results indicate that acute bilateral sectioning of the IBAT intercostal nerves blocks the IBAT temperature and capillary blood flow increases evoked by VMH electrical stimulation.