Collagen induced human platelet aggregation: serotonin receptor antagonism retards aggregate growth in vitro.

Abstract

OBJECTIVE:

The role of platelet derived serotonin (5-HT) in collagen induced human platelet aggregation was examined both in hirudinised plasma and whole blood. Hirudin was used to maintain normocalcaemia, thereby avoiding erroneous findings often obtained with citrated blood.

METHODS:

Platelet aggregation, aggregate growth, and primary platelet aggregation were quantified by optical aggregometry and platelet counting respectively.

RESULTS:

In plasma, platelet aggregation induced by 5-HT (3 microM) in the presence of adrenaline (1 microM) was inhibited by more than 85% by ICI 170809 (3 microM, IC50 0.1 microM), a specific platelet 5-HT2 antagonist. With collagen (0.5 micrograms.ml-1), ICI 170809 retarded the rate of aggregation by 30%, whereas aspirin abolished the response. In contrast, ICI 170809 inhibited collagen induced primary aggregation by less than 10% in both plasma and whole blood.

CONCLUSIONS:

(1) 5-HT contributes to collagen induced aggregate growth and 5-HT2 receptor antagonism with ICI 170809 retards the rate of growth. (2) This could explain the efficacy of 5-HT2 antagonists in limiting coronary thrombosis despite the limited role of 5-HT in primary aggregation.

• Authors: V C Menys
• Journal: Cardiovascular research (Cardiovasc Res) Vol. 27 Issue 11 Pg. 1916-9 (Nov 1993) ISSN: 0008-6363 [Print] England
• PMID: 8287397 (Publication Type: Journal Article)

Chemical References

• Hirudins
• Quinolines
• Recombinant Proteins
• Serotonin Antagonists
• Serotonin
• ICI 170809
• Collagen
• Apyrase
• Aspirin
• desirudin
• Epinephrine

Topics

• Apyrase (pharmacology)
• Aspirin (pharmacology)
• Blood Platelets (drug effects)
• Collagen (pharmacology)
• Epinephrine (pharmacology)
• Hirudins (analogs & derivatives, pharmacology)
• Humans
• In Vitro Techniques
• Platelet Aggregation (drug effects)
• Platelet Count
• Quinolines (pharmacology)
• Recombinant Proteins (pharmacology)
• Serotonin (pharmacology)
• Serotonin Antagonists (pharmacology)