Serotonin whole blood

Salazar D, Chaikin P, Swanson B, et al. The effects of nefazodone and fluoxetine on platelet serotonin uptake and whole blood serotonin. Clin Pharmacol Ther 1994 55 137. 

Anderson GM, Freedman DX, Cohen DJ, Volkmar FR, Hoder EL, McPhedran P, Minderaa RB, Hansen CR, Young JG (1987) Whole blood serotonin in autistic and normal subjects. 1 Child Psychol Psychiatry 28 885-900... 

Serotonin can be measured in whole blood, serum, platelet-rich plasma, platelet-poor plasma (i.e., platelet-free plasma), isolated platelet pellets, urine, and CSF. Most blood serotonin is stored in the platelets and is easily released during sample preparation. For whole blood serotonin, venous blood (10 mL) is drawn into a tube containing potassium EDTA as an anticoagulant, gently mixed, placed on ice, and transferred to a storage tube. An aliquot of blood is then removed for a platelet count alternatively, a simultaneous EDTA blood sample can be collected. Antioxidants such as ascorbic acid or metabisulfite are conveniently added to the storage tube when a fluorometric detection system is used. Blood serotonin samples are stored frozen at -20 °C, preferably within 2 hours after collection. 

Carling RS, Degg TJ, AUen KR, Bax ND, Barth JH. Evaluation of whole blood serotonin and plasma and urine 5-hydroxymdole acetic acid in diagnosis of... 

Studies on MAO-A deficiency are limited to one family and only urine has been analysed. It is probable that elevated whole blood serotonin and plasma catecholamines would also point to this condition. 

B. Whole Blood Serotonin Levels after Infusion ... 

Serotonin (5-HT) abnormalities. Schizophrenic patients with abnormal brain scans have higher whole blood 5-HT concentrations, and these concentrations correlate with increased ventricular size. 

Danaceau JP, Anderson GM, McMahon WM, Crouch DJ. 2003. A liquid chromatographic-tandem mass spectromet-ric method for the analysis of serotonin and related indoles in human whole blood. J Anal Toxicol 27 440. 

Hyperserotonemia has been a consistent finding in subjects with autism, which may be due to activity of serotonin-associated platelet proteins (Hranilovic et al., 2008, 2009). Interestingly, 99% of blood serotonin is contained in platelets (Anderson et al., 1987) and studies have shown that there is an approximate 50% increase in blood-levels of serotonin in subjects with autism vs. controls (McBride et al., 1998). Hypotheses for increased serotonin include increased synthesis of serotonin by tryptophan hydroxylase (TPHl), increased uptake of serotonin into platelets via serotonin transporters (5-HTT), diminished release of serotonin from platelets via serotonin 2A receptor, and decreased breakdown of serotonin by monoamine oxidase (MAOA) (Hranilovic et al., 2008). A study by Hranilovic et al. (2008) identified polymorphisms of tryptophan hydroxylase and MAOA with increased serum serotonin levels. Similarly, haplotype analysis has shown a significant association between polymorphisms of TPHl and increased serotonin in whole blood (Cross et al., 2008). 

Platelet-rich plasma samples are prepared from whole blood by centrifuging at 120g for 30 minutes at 4 or at 200 for 15 minutes at room temperature. To prevent lowering the serotonin concentration, platelet-rich plasma is prepared within 1 hour after the blood is collected and placed on ice. An aliquot of platelet-rich plasma is removed for a platelet count. Platelet-poor plasma and platelet pellets are prepared from measured aliquots of the platelet-rich sample plasma by centrifuging at 4500 for 10 minutes at 4 (or at lOOOg for 30 minutes at room temperature). To reduce the probability of platelet rupture, samples should never be frozen before the cell-free plasma is obtained. Plasma and pellets are stored frozen at -20 °C and analyzed within 1 to 2 weeks after collection. 

Whole blood measurement of serotonin is popular because time-consuming isolation of platelets is not... 

Anderson GM, Feibel PC, Cohen DJ. Determination of serotonin in whole blood, platelet-rich plasma, platelet-poor plasma and plasma ultrafiltrate. Life Sd 1987 40 1063-70. 

Pussard E, Guigueno N, Adam O, Giudicelli JF. Validation of HPLC-amperometric detection to measure serotonin in plasma, platelets, whole blood, and urine. Clin Chem 1996 42 1086-91. 

Launay, J. M., Copel, L., Callebert, J., Corvaia, N., Lepage, E., Bricaire, F., Saal, F., and Peries, J., Decreased whole blood 5-hydroxytryptamine (serotonin) in AIDS patients, /. Acquir. Imm. Defic. Syndr., 1, 324, 1988. 

Coleman, M., Serotonin concentrations in whole blood of hyperactive children, /. Pediatr., 78(6), 985, 1971. 

Serotonin In blood serotonin is predominantly located in the platelets, with levels in plasma being 100-fold lower. Most analysts interested in serotonin measurements have concentrated on determining serotonin in whole blood or platelet rich plasma. The presence of monoamine oxidase enzymes in blood necessitates the use of an enzyme inhibitor, e.g., pargyline to prevent the conversion of serotonin to 5-HIAA prior to analysis. Similar chromatographic conditions to those used for catecholamines can be used, e.g., CIS reversed-phase columns and electrochemical detection at an oxidation potential of -I-0.75 V or fluorescence detection. Sample... 

An interdigitated gold microarray electrode coated with Nation has recently been used to detect serotonin in human whole blood samples (20 pL) to monitor allergic response, during which serotonin is secreted into the bloodstream [111]. Results showed excellent agreement between electrochemically monitored serotonin... 

Serotonin has been found to exert an intense vasoconstrictor effect on the pulmonary circulation 1 . Although the pulmonary vasoconstrictor effect of serotonin can be demonstrated easily by pharmacological methods, its physiological and pathophysiological roles have not been unequivocally demonstrated. In fact, the infusion of serotonin (1. 85 - 5. 5 mcg/kg/min) into the pulmonary artery of seven human subjects produced a definite rise in pulmonary artery pressure in only one instancel. Most of the serotonin found in whole blood is stored in platelets. This would imply that in the process of platelet aggregation to form a thrombus, serotonin would be available for release . Pulmonary vasoconstriction does occur as a result of pulmonary thrombosis. A further indication that serotonin could be implicated in the thrombosis-induced pulmonary vasoconstriction is the finding that 82 per cent of serotonin can be released from platelets by thrombin in five minutes. ... 

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