A Possible Role Played by Central Monoamine neurones in Thermo‐Regulation

The effect of a cold and warm environment on the activity of the central catecholamine (CA) and 5‐hydroxytryptamine (5‐HT) neurones has been studied with the help of a combined biochemical and histochemical approach using inhibitors of the tyrosine and tryptophane hydroxylase. The central noradrenaline (NA) and 5‐HT neurones of rats kept at: 40d̀ C were found to increase their state of neuronal activity. whereas the 5‐HT but not the CA neurones of rats kept at ± 3d̀ C showed a decreased neuronal activity. These results indicate that the central NA and 5‐HT neurones participate in thermo‐regualtion.