5‐Hydroxytryptamine uptake and release in relation to aggregation of rabbit platelets
- 1 April 1969
- journal article
- Published by Wiley in The Journal of Physiology
- Vol. 201 (2) , 409-423
- https://doi.org/10.1113/jphysiol.1969.sp008763
Abstract
1. The aggregation of blood platelets was measured in vitro at different time intervals after the addition of 5-hydroxytryptamine (5-HT) or of reserpine to platelet-rich plasma of untreated rabbits and of rabbits injected with reserpine and 5-HT, i.e. while the platelets were taking up 5-HT or releasing it under the influence of reserpine.2. When 5-HT was added to stirred platelet-rich plasma the platelets aggregated reversibly within 1 min. The velocity of aggregation increased with 5-HT concentrations of 0.1-30 muM and decreased with higher concentrations.3. (-)-Adrenaline, which alone did not produce aggregation, markedly accelerated the aggregation caused by 5-HT. The acceleration was greatest when 5-HT and adrenaline were added simultaneously.4. 5-HT added to the platelet-rich plasma in amounts that exceeded the 5-HT capacity of the platelets progressively diminished the velocity of aggregation produced by 5-HT plus adrenaline until aggregation was completely inhibited. Smaller amounts of 5-HT produced a transient inhibition of aggregation.5. The aggregation of platelets from reserpinized rabbits was inhibited by less 5-HT than the aggregation of platelets from normal rabbits.6. (-)-Adrenaline aggregated platelets of untreated rabbits but not those of reserpinized rabbits or of rabbits injected with 5-HT when reserpine was added in vitro 1-30 min previously.7. Platelets obtained from rabbits treated first with reserpine and subsequently injected with 5-HT were not aggregated by 5-HT plus adrenaline. During incubation in vitro these platelets progressively recovered their aggregability but this recovery was delayed by the monoamine oxidase inhibitor Pargyline.8. Imipramine in concentrations which did not influence platelet aggregation by adenosine diphosphate (ADP) abolished aggregation produced by 5-HT or by 5-HT plus adrenaline.9. The inhibitory effect of adenosine on platelet aggregation was concentration-dependent and similar whether aggregation was produced by ADP, 5-HT or 5-HT plus adrenaline.10. It is proposed that aggregation brought about by 5-HT is connected with its active uptake into the platelets and is caused by ADP formed from ATP during the active uptake of the amine. When 5-HT is no longer actively taken up, it also ceases to cause or to potentiate aggregation.Keywords
This publication has 15 references indexed in Scilit:
- METABOLISM, TRANSFER AND STORAGE OF 5‐HYDROXYTRYPTAMINE IN BLOOD PLATELETS*British Journal of Pharmacology, 1968
- Action of reserpine and imipramine on intracellular storage of 5-hydroxytryptamine in blood plateletsCellular and Molecular Life Sciences, 1967
- Two sites of 5-hydroxytryptamine uptake in blood plateletsLife Sciences, 1967
- On the membrane effects of chlorpromazine: uptake of biologic amines by the blood platelet and red cellInternational Journal of Neuropharmacology, 1964
- Formation of 5-Hydroxytryptophol from Endogenous 5-Hydroxytryptamine by Isolated Blood PlateletsNature, 1964
- The aggregation of blood plateletsThe Journal of Physiology, 1963
- Aggregation of Blood Platelets by Adenosine Diphosphate and its ReversalNature, 1962
- THE EFFECT OF IPRONIAZID AND IMIPRAMINE ON THE BLOOD PLATELET 5‐HYDROXYTRYPTAMINE LEVEL IN MANBritish Journal of Pharmacology and Chemotherapy, 1960
- The uptake of 5-hydroxytryptamine by blood platelets in the coldThe Journal of Physiology, 1959
- IDENTIFICATION AND ASSAY OF SEROTONIN IN BRAIN1956