Effects of maprotiline, nomifensine, and trazodone on monoamine turnover in the limbic system

ABSTRACT

The effects of 14-day treatment of three antidepressant drugs [maprotiline, nomifensine, and trazodone] was studied on the turnover of norepinephrine, dopamine and serotonin in 4 limbic areas of rat brain hypothalamus, hippocampus, amygdala and olfactory tubercle. The monoamine metabolites accumulated in those brain areas were analyzed by HPLC method. The 3 drugs produced significant increase in the level of norepinephrine metabolite [MHPC] in the hypothalamus and hippocampus, nomifensine increased its level also in the olfactory tubercle. In the amygdala, maprotiline significantly decreased while the two other drugs slightly increased the MHPG level on the Dopamine metabolite [HVA]. Nomifensine significantly increased its level in the hippocampus, hypothalamus and the olfactory tubercle and trazodone produced the highest increase in the amygdala. On serotonin metabolite [5-HIAA] trazodone produced marked increase of its level in the hypothalamus, hippocampus and amygdala and maprotiline markedly increased its level in the amygdala. The results indicated that the primary action of maprotiline is to enhance norepinephrine turnover, while nomifensine markedly increased turnover of both norepinephrine and dopamine and trazodone markedly increased turnover of serotonin and norepinephrine