THE EFFECT OF EXPOSURE TO HEAT AND COLD UPON RAT BRAIN CATECHOLAMINE AND 5-HYDROXYTRYPTAMINE LEVELS

Abstract

A study was made of the possible relationship between the amine levels (dopa, dopamine, noradrenaline, and 5-hydroxytryptamine (5-HT)) of whole brain and of the hypothalamus and the body temperature of the male albino rat. Acute exposure to a warm environment (34 °C and 40 °C) and acute exposure to cold (20 °C and 3 °C) produced no significant changes in amine levels in spite of a hyperthermia of 3 °C and a hypothermia of 0.7 °C. A maintained hypothermia of about 1.5 °C occurred in the rats exposed to cold over a 30-day period, but only late in the exposure period were significant changes in dopamine and noradrenaline observed.