The effects of chronic clomipramine and mianserin on the activity of tryptophan hydroxylase in the rat brain

Abstract

The activity of tryptophan hydroxylase was measured in the rat brainstrem and cortex by the rat of in vivo accumulation of 5-hydroxytryptophan after inhibition of aromatic amino acid decarboxylase with 3-hydroxybenzyl-hydrazine.The activity of the enzyme was higher at mid-dark than mid-light in the two brain areas.Chronic administration of clomipramine increased the enzymatic activity at the two time of day to different levels of significance.In contrast chronic mianserin led to a decrease but only to different levels of significance in the cortex.The significance of these results are discussed in relation to the theories implicating circadian rythms in the mechanism of anti-depressant action