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.