Effect of fluvoxamine on 5-hydroxytryptamine uptake, paroxetine binding sites and ketanserin binding sites in the Japanese monkey brain and platelets, in vivo and in vitro

We investigated the in vitro effects of fluvoxamine on ³H-paroxetine binding and ³H-monoamine uptake in monkey cerebral cortex in comparison with those of other antidepressants. Fluvoxamine selectively inhibited ³H-5-hydroxytryptamine (5-HT) uptake and ³H-paroxetine binding. However, it did not alter ³H-norepinephrine or ³H-dopamine uptake. In addition, we examined the effects of chronic treatment with fluvoxamine (5 mg/kg per day, p.o.) on 5-HT uptake sites that bind ³H-paroxetine and 5-HT₂ receptors that bind ³H-ketanserin, in monkey brains and platelets. Chronic treatment with fluvoxamine affected neither the paroxetine binding sites nor the kentanserin binding sites of the brains and platelets. These results suggest that long-term treatment with fluvoxamine does not affect either the 5-HT uptake sites or 5-HT₂-receptors of 5-HT neurons in monkey brain in spite of its strong inhibitory effect on 5-HT uptake in vitro.