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Journal Article 2011; 32(3): 292-300 PubMed PMID: 21712781 Citation  Keywords:  Actin Cytoskeleton:metabolism, Actins:chemistry, Animals, Antioxidants:metabolism, Biomarkers:analysis, Cytochalasin B:pharmacology, Erythrocyte Deformability:drug effects, Erythrocyte Membrane:drug effects, Erythrocytes:drug effects, Hemolysis:drug effec.   

BACKGROUND: Some researches have shown that melatonin (MLT) has effects on the erythrocyte deformability and on the osmotic fragility which, currently, seem to be heterogeneous and fragmentary.

OBJECTIVE: This work wished to evaluate in vitro the possible modifying action of MLT at pharmaceutical doses on the osmotic fragility of rat blood samples treated with cytochalasin B (CB). The variation of the lactate dehydrogenase (LDH) levels have been measured because LDH is an enzyme which is considered an important marker of hemolysis. Working in a strongly reducing environment has been necessary in order to avoid possible antioxidant actions of MLT, measuring the plasma levels of malondialdehyde and total phospholipids in order to highlight possible MLT actions which are not related to its recognized antioxidant properties.

RESULTS: The data show a possible MLT action which strengthens the CB action on the osmotic fragility and on the membrane deformability of the erythrocytes.

CONCLUSIONS: Under the adopted working conditions, a direct relation of MLT with the biochemical dynamics of the cytoskeleton-mediated processes can be suggested. Further studies will be needed to clarify the mechanisms and the extent of the observed phenomena....

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Clinical Trial 2006; 27(3): 307-313 PubMed PMID: 16816836 Citation  Keywords:  Antidepressive Agents, Second-Generation:blood, Antidepressive Agents, Tricyclic:blood, Erythrocyte Membrane:drug effects, Female, Humans, Male, Neurotransmitter Uptake Inhibitors:blood, Plasma:metabolism, Reference Values, Structure-Activity Relationship.   

OBJECTIVE: The distribution of different antidepressants between plasma and red blood cells (RBCs) or between water and erythrocyte membranes (ghosts) has not been sufficiently compared so far.

MATERIALS AND METHODS: Distribution of seven antidepressants (amitriptyline, nortriptyline, imipramine, desipramine, didesmethylimipramine, dothiepin, and citalopram) was measured in vitro in small volumes of blood or erythrocyte membrane suspension using radiolabeled drugs. Blood samples were taken from healthy subjects.

RESULTS: The distribution of antidepressants between plasma and RBCs is strongly affected by temperature; however, it does not depend on the antidepressant concentration in the range of their therapeutic concentrations. The data analysis proved that the ratio of RBCs to plasma volume concentrations is the suitable parameter characterizing antidepressant distribution in whole blood. Significantly higher ratios of RBCs to plasma concentrations were found for demethylated metabolites of tricyclic antidepressants and in the case of citalopram. Citalopram showed the highest accumulation in intact RBCs and at the same time the lowest binding to isolated membranes. The binding of drugs to isolated erythrocyte membranes was much higher than in whole blood.

CONCLUSION: The concentration ratio of antidepressant in RBCs and in plasma is sensitive not only to the binding properties of plasma proteins and cell membranes, but also to changes in drug molecule, both in aminopropyl chain and in aromatic rings. This ratio is to a large extent characteristic of a particular antidepressant....

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