Serotonin in Platelets

Abstract The discovery of serotonin in platelets in the 1950s heralded a new era of research in the study of blood clot formation. Platelets, which represent the cellular components in the blood responsible for initiating blood clot formation, are responsible for maintaining a low concentration of plasma serotonin by sequestering and storing a remarkable concentration of serotonin. While platelets are vital for regulating circulating serotonin levels in the plasma, serotonin itself is suggested to play a fundamental role in both platelet function and blood clot formation. However, despite many studies, the role for serotonin in thrombus formation is still not completely elucidated. This chapter will explore a brief history of both platelets and serotonin and present a current understanding of the interactions between the two. Here we discuss the vital role of platelets in the regulation of circulating serotonin concentrations, the significant role of serotonin in platelets for the hemostatic and thrombotic responses, and the clinical implications of modulating this process in health and disease.