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INTERACTION BETWEEN PLATELET‐RELEASED SEROTONIN AND THROMBOXANE A 2 ON HUMAN DIGITAL ARTERIES
Author(s) -
Young M. S.,
Iwanov V.,
Moulds R. F. W.
Publication year - 1986
Publication title -
clinical and experimental pharmacology and physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.752
H-Index - 103
eISSN - 1440-1681
pISSN - 0305-1870
DOI - 10.1111/j.1440-1681.1986.tb00328.x
Subject(s) - ketanserin , chemistry , 5 ht receptor , platelet , thromboxane a2 , serotonin , thromboxane , medicine , endocrinology , verapamil , nifedipine , agonist , antagonist , pharmacology , calcium , receptor , biochemistry
SUMMARY 1. Synergism between the contractile effects of platelet‐derived serotonin (5HT) and thromboxane A 2 (TXA 2 ) on a human blood vessel has been investigated by incubating strips of digital arteries in subcontractile concentrations of either 5HT or the TXA 2 ‐mimetic agent U46619. 2. Either agonist U46619 or 5HT, in subcontractile concentrations, significantly potentiated the contractile response to the other. 3. The 5HT antagonist ketanserin (10 (μmol/1), theCa 2+ antagonist drugs verapamil (3 μmol/l), or nifedipine (10 nmol/l), or a Ca 2+ ‐free bathing medium, reduced the contractile responses to 5HT, but had no effect on the potentiation mediated by U46619. 4. The interaction between TXA 2 and 5HT derived from platelets was studied by measuring responses to platelets 1 min after aggregation (in the absence or the presence of ketanserin 10 μmol/l), and 20 min after aggregation. The results indicated that the response to platelets mediated by TXA 2 and 5HT was greater than the sum of those mediated by TXA 2 or 5HT separately. 5. It is concluded that synergism between the contractile effects of 5HT and U46619 occurs in human blood vessels; that this is mediated by enhanced utilization of intracellular, rather than extracellular calcium; and that synergism can also occur when 5HT and TXA 2 are released from stimulated human platelets.