Inhibition of in vitro amine uptake into rat brain synaptosomes after in vivo administration of antidepressants.

The effects of in vivo administration of a number of antidepressants in doses up to 30 mg/kg i.p. on the in vitro uptake of 3H-amines were determined. The uptake of noradrenaline (NA) was competitively inhibited by 50% by desipramine, nomifensine and clomipramine. Dopamine uptake in the corpus striatum was inhibited by 50% by nomifensine. The uptake of 5-hydroxytryptamine (5-HT) was inhibited by clomipramine and fluoxetine. Iprindole and mianserin did not inhibit NA, DA or 5-HT uptake by more than 20%. The results demonstrate that the selectivities and potencies of antidepressants may be different in vivo to those in vitro. Thus, care should be taken when extrapolating to in vivo experiments, selectivities and potencies obtained in vitro.