Effect of heat exposure on the activity of monoamine oxidase in the rat brain and interscapular brown adipose tissue

The exposure of Wistar male rats (200 +/- 20 g) to high ambient temperature (38 degrees C) for 20 and 60 min induced an equal decrease in hypothalamic , brain stem and hippocampal monoamine oxidase activity when compared to co ntrols. The interscapular brown adipose tissue monoamine oxidase activity, as well as oxygen consumption and rectal temperature were increased only af ter a 60 min heat exposure. The adrenal function, assessed by dopamine-beta -hydroxylase activity and cholesterol concentration, was enhanced both afte r 20 and 60 min. In conclusion, heat induced the increase in adrenal functi on and interscapular brown adipose tissue monoamine oxidase activity, but t he decrease in that of the brain. (C) 2000 Elsevier Science Ltd. All rights reserved.