Effects of monoamine uptake inhibitors on extracellular and platelet 5‐hydroxytryptamine in rat blood: different effects of clomipramine and fluoxetine

• DOI: 10.1111/j.1476-5381.1992.tb09082.x
• Publication Date: 2012-07-19T22:09:12Z
• Authors: Jordi Ortiz; Francesc Artigas
• Keywords: Desipramine; Clomipramine; Fluvoxamine; Paroxetine; Sertraline

The concentration of 5‐hydroxytryptamine (5‐HT) in rat platelet‐free plasma increased significantly 30 min after a single i.p. injection (10 mg kg −1 ) each six inhibitors the high‐affinity 5‐HT uptake (fluvoxamine, fluoxetine, alaproclate, paroxetine, sertraline and clomipramine). increases ranged from 226% to 776% control values. In contrast, imipramine, desipramine femoxetine had no significant effect. increase elicited by paroxetine was dependent on dose (1, 5 10 returned values 4 h. That observed clomipramine also transient paralleled drug (Spearman‐rank correlation r = 0.43). vivo , pulmonary vascular endothelium removed trace amounts (8.8 nmol bolus) intravenously injected [ 14 C]‐5‐HT. Paroxetine pretreatment before‐hand) reduced this 73%. Repeated fluoxetine treatments whole blood (ca. − 60% daily 2× during days). However, (extracellular) not increased. Various repeated with (i.p. injections or osmotic minipumps, up day ), failed decrease concentrations. Platelet‐free unchanged, even yielding levels 2.7 times higher than those that it acutely. These results indicate extracellular pool (measured plasma) is physiologically under systems. sustained inhibition does result an plasma, suggesting adaptative mechanisms are triggered. distinct long‐term effects two antidepressants suggest differential action uptake.