IONOPHORE A-23187 AND THROMBASTHENIC PLATELETS - MODEL FOR DISSOCIATING SEROTONIN RELEASE AND THROMBOXANE FORMATION FROM TRUE AGGREGATION

The calcium ionophore A 23187 (iono.) induced a change in light transmission (LT) of thrombasthenic (thr.) platelets (pl.) either in plasma or washed and resuspended in buffer. This was not due to aggregation, but was associated with the formation of a central contractile gel mass and central apposition of organelles ; lactic dehydrogenase determination showed no evidence of platelet lysis. After incorporation of [14C]-arachidonic acid into the platelet phospholipid pool, stimulation with the iono. showed similar profiles of oxygenated products for both normal and thr. pl., providing evidence for a normal activity of phospholipase(s) in thr. pl. under these conditions. The iono. induced normal thromboxane (TX) synthesis and serotonin (5HT) release in thr. pl.; the TX formation but not the accompanying change in LT, was inhibited by aspirin. The action of the iono. on thr. pl. thus provides a natural model for studying TX formation and 5HT release in the absence of aggregation. © 1979.