Serotonergic status in human blood.
Preliminary data on the existence of a plasma pool of serotonin (5HT) in human blood has been confirmed in a descriptive study of two distinctive pools of 5HT (plasma and platelet), and its metabolite 5-hydroxyindoleacetic acid (5HIAA), in the blood of 175 healthy individuals. Plasma 5HT (0.93 +/- 0.67 ng/mL, X +/- S.D.) shows a significant but low correlation with platelet 5HT (711 +/- 319 ng/10(9) platelets) (r=0.29, p less than 0.001). Diastolic blood pressure correlated significantly with plasma 5HT (r=0.51, p less than 0.05) and whole blood 5HT (r=0.52, p less than 0.05) in older individuals (50-65 years) but not in the whole group (r=0.052, n.s.). Differences between sexes include plasma 5HT, whole blood 5HT (both higher in women) and plasma 5HIAA (lower in women) and may reflect a differential whole body 5HT function. The effect of meal consumption and a peripheral 5HT synthesis inhibitor (carbidopa) in four human subjects has also been tested. Carbidopa (0.7 mg/kg) significantly lowers the plasma pool of 5HT (mean change -33%) 2 hr. after administration, while platelet 5HT is unchanged. These data support the existence of a human plasma 5HT pool, with a rapid turnover, different from the 5HT in platelets (slow turnover, reserve pool). Both may be useful in evaluating different aspects of 5HT-mediated pathologies.
Ortiz
J
J
Department of Neurochemistry, C.S.I.C., Barcelona, Spain.
Artigas
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F
Gelpí
E
E
D000328:Adult; D000367:Age Factors; D001792:Blood Platelets / Q000032:analysis*; D001794:Blood Pressure; D005260:Female; D006801:Humans; D006897:Hydroxyindoleacetic Acid / Q000097:blood; D008297:Male; D010976:Platelet Count; D012016:Reference Values; D012701:Serotonin / Q000097:blood*; D012737:Sex Factors
D012701:Serotonin; D006897:Hydroxyindoleacetic Acid