Time course of the changes of catecholamine levels in rat brain during swimming stress

The time course of the changes in the levels of adrenaline, noradrenaline and dopamine was investigated in rat hypothalamus, ponsmedulla and midbrain during 4-h swimming at 35 degrees C. The adrenaline levels showed gradual decrease whereas the noradrenaline and dopamine levels were kept in almost steady-state during the swimming. These findings suggest that brainstem adrenaline levels are not so fast adaptive as the noradrenaline and dopamine levels under the stress.