IDENTIFICATION OF SEROTONIN TRANSPORTER MESSENGER-RNA IN RAT PLATELETS

Total RNA was isolated from rat platelets by guanidinium - acid - phen ol extraction, and mRNA for the serotonin (5-hydroxytryptamine) transp orter (5HTt) was identified. From a typical starting sample of 20 mL o f rat blood (similar to 9 x 10(9) platelets), 14 to 17 mu g of total p latelet RNA was obtained. Northern blot analysis, using P-32-labeled 5 HTt cDNA as a probe, identified similar to 3.3 kb long 5HTt mRNA. Afte r rehybridization with cyclophilin cDNA, similar to 1 kb long mRNA for cyclophilin, which could serve as a reference for 5HTt mRNA quantific ation, was also identified. Densitometric analysis demonstrated clearl y measurable signals for both mRNAs. The possibility of quantification of rat platelet 5HTt mRNA should enable parallel studies on 5HTt gene expression in platelets and brain of the same animal, and the evaluat ion of the platelet model at the molecular genetic level.