5-Hydroxytryptamine and platelets: uptake and aggregation in hypoxic pulmonary hypertensive rats

• Published in: European journal of pharmacology Vol. 459; no. 1; pp. 1 - 7
• Main Authors: Awabdy, Doreen, Bryan-Lluka, Lesley J., Wanstall, Janet C.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 10-01-2003; Elsevier
• Subjects: 5-HT (5-hydroxytryptamine, serotonin); Adenosine Diphosphate - pharmacology; Aggregation; Animals; Biological and medical sciences; Blood Platelets - metabolism; Collagen - pharmacology; Dose-Response Relationship, Drug; Hematocrit; Hypertension, Pulmonary - blood; Hypertension, Pulmonary - etiology; Hypertension, Pulmonary - pathology; Hypoxia - complications; Hypoxic pulmonary hypertension; Male; Medical sciences; Myocardium - pathology; Organ Size; Paroxetine - pharmacology; Platelet; Platelet Aggregation - drug effects; Platelet Count; Pneumology; Pulmonary hypertension. Acute cor pulmonale. Pulmonary embolism. Pulmonary vascular diseases; Rats; Rats, Wistar; Serotonin - pharmacokinetics; Serotonin - pharmacology; Serotonin Uptake Inhibitors - pharmacology; SERT (serotonin transporter); Aggregation; Platelet; 5-HT (5-hydroxytryptamine, serotonin); Hypoxic pulmonary hypertension; SERT (serotonin transporter); Rat; Lung; Cardiovascular disease; Smooth muscle; ADP; Respiratory system; Blood vessel; Vasoconstrictor agent; Pathophysiology; Serotonin; Respiratory disease; Rodentia; Muscle contraction; Pulmonary hypertension; Vertebrata; Mammalia; Animal; Collagen; Interindividual comparison; Neurotransmitter; Hypoxia
• ISSN: 0014-2999; 1879-0712
• DOI: 10.1016/S0014-2999(02)02734-6

Pulmonary hypertension is associated with various alterations in 5-hydroxytryptamine (5-HT) physiology. In this study in platelets from hypoxic pulmonary hypertensive rats (10% O
2; 1 week) and normoxic rats (room air), (i) initial rates of specific [
3H]5-HT uptake were measured and (ii) potentiation of collagen- and ADP-induced aggregation by 5-HT was quantified. The platelet count was almost halved in hypoxic rats. In uptake experiments, there was a decrease in 5-HT uptake in platelets from hypoxic compared with normoxic rats, due to a 36% reduction in the maximal initial rate of uptake. The aggregation experiments showed that 5-HT (1–100 μM) increased the magnitude of responses to collagen and the duration of responses to ADP, but there was no difference between hypoxic and normoxic rats. Abnormalities in platelet function may conceivably lead to increases in plasma 5-HT levels in hypoxic pulmonary hypertension, but are unlikely to aggravate pulmonary thromboembolism.