Platelet serotonin uptake: methods and strain differences.

The pharmacokinetic properties of platelets make these vascular elements a potential and convenient model for serotoninergic neurons. Because we encountered several difficulties in preliminary platelet serotonin (5HT) uptake assays, we explored the influence of several assay factors on the parameters obtained. We found that a citrate-dextrose anticoagulant stabilized platelet 5HT uptake even at room temperature. More rapid wash rates during the filtration following the assay incubation gave higher apparent uptake affinities. Platelets from an inbred strain of rats exhibited less variability in Vmax than cells from outbred strains studied. These findings, in conjunction with a human twin study also suggesting that variance in platelet 5HT uptake increases with genetic diversification, demonstrate some additional confounding factors in platelet 5HT uptake studies.