Endogenous levels and turnover of catecholamines in mouse brain after repeated administration of haloperidol.

Abstract

The endogenous levels of dopamine and noradrenaline in the mouse brain and the accumulation of 14C-labelled catecholamines formed from 14C-tyrosine were investigated in normal and haloperidol pretreated mice. In the withdrawal phase after repeated administration of haloperidol (1.25 mg/kg p. o./day, 5 days) there was an increased synthesis of 14C-dopamine 2 h after the last dose of haloperidol. Synthesis had reverted to normal 24 h later and remained normal for 4 days. The synthesis of 14C-noradrenaline as well as the endogenous level of both dopamine and noradrenaline was unchanged during the 5 days after withdrawal.