G. Sokoloff et al., FURTHER EVIDENCE THAT BAT THERMOGENESIS MODULATES CARDIAC RATE IN INFANT RATS, American journal of physiology. Regulatory, integrative and comparative physiology, 43(6), 1998, pp. 1712-1717
Previous research in infant rats suggested that brown adipose tissue (
BAT), by providing warm blood to the heart during moderate cold exposu
re, protects cardiac rate. This protective role for BAT thermogenesis
was examined fur ther in the present study. In experiment 1, 1-wk-old
rats in a warm environment were pretreated with saline or chlorisondam
ine (a ganglionic blocker), and then BAT thermogenesis was stimulated
by injection with the beta 3-agonist CL-316243. In experiment 2, pups
were pretreated with chlorisondamine and injected with CL-316243, and
after BAT thermogenesis was stimulated the interscapular region of the
pups was cooled externally with a thermode. In both experiments, card
iac rate, oxygen consumption, and physiological temperatures were moni
tored. Activation of BAT thermogenesis substantially increased cardiac
rate in saline- and chlorisondamine-treated pups, and focal cooling o
f the interscapular region was sufficient to lower cardiac rate. The r
esults of these studies support the hypothesis that BAT thermogenesis
contributes directly to the modulation of cardiac rate.