Methodological Investigations on the in Vitro Uptake of 5‐hydroxytryptamin by Human Blood Platelets

Abstract

Blood platelets and monoamine-containing nerve endings of the brain share anatomical and functional properties, particularly with regard to active uptake, storage, and release of 5-hydroxytryptamin (serotonin). Thus experimentally induced changes in the serotonin metabolism of blood platelets may reflect changes occurring intraneuronally (Page ( 1968), Paasonen ( 1968), Murphy ( 1969) ).In a series of investigations on the effect of drugs used in manic-depressive illness, e. g. lithium, on brain serotonin metabolism, we were therefore interested in examining also the effect of these drugs upon blood platelets in vit 7 0 .However, with this particular aim of the study, it was felt that some of the usually applied analytical procedures for examination of blood platelets might lead to erroneous conclusions. We were, in this respect, particularly concerned about the use of Ca++-and Mg++ -removing anticoagulants.The present study was undertaken to establish the significance, for this particular type of investigation, of some analytical details, i. e. type of incubation medium, incubation period, concentration of serotonin and pH of the incubation medium, and the use of anticoagulants. MATERIALS AND METHODSBlood from healthy volunteers was drawn 30-60 min after breakfast from a cubital vein. No drugs were allowed during 8 days prior to the experiment.Two days prior to the experiment, the person was kept on a diet devoid of serotonin-rich food. Tobacco and caffein-containing drinks were avoided on the morning of sampling. EDTA and heparin were added dissolved in 200 pl 0.9 "/o saline to final concentration of 1 mg EDTA/ml blood and 4 i. u. heparinlml blood.

The Effect of Percutaneous Nitroglycerin Upon the Concentration of Serotonin, Epinephrine and Norepinephrine in Venous Blood From Migrainous Subjects During Attack‐free Intervals

“…Materials in connection with blood platelets was siliconized. The platelet count was performed as previously described (Genefke, 1971) 5 . Plasma cathecholamines are determined by an enzymatic double labeled isotope derivative tecnic (Engelman & Portnoy, 1970, Juel Christensen, 1973 6,7 .…”

Serotonin (5‐hydroxytryptamine) Release and Uptake in Platelets From Healthy Persons and Migrainous Patients in Attack‐free Intervals

“…38 ± 8 199 ± 40 scribed (Genefke, 1971). 22 5-HT in platelets was estimated by Udenfriends method (1955) 23 as modified by Crawford (1963). 24 The fluorescence was measured in an Aminco-Bowman spectrophotofluorometer.…”

Therapeutic Effect of Reserpine on Migraine Syndrome: Relationship to Blood Mine Levels

“…11 Platelet counts were performed as previously described. 12 Plasma norepinephrine (NE) and epinephrine (E) were determined separately by a double isotope derivation technique. 13,14…”