Heart (IMAGE) University of North Carolina Health Care Caption Drugs vary in their ability to activate the 5-HT2B serotonin receptor. Some drugs (RED) strongly activate the receptor and cause potentially life-threatening valvular heart disease while others only weakly activate it (GREEN) and are less likely to cause serious side-effects. Credit Roth Lab Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.