Succinate potentiates the action of platelet agonists

Succinate potentiated the actions of ADP, epinephrine, and the endoperoxide analog U46619 on platelets in plasma. Potentiation was observed at concentrations as low as 400 microM. Potentiation occurred immediately and did not change during incubations as long as five min. It was also observed with maleate and malonate but not with fumarate, oxalate, glutarate or succinate analogs with one or both carboxyls blocked. Succinate was able to reverse the inhibition of platelet activation due to elevated cAMP, and succinate and maleate were comparable to ADP in their ability to inhibit PGI2-induced synthesis of cAMP.