Effects of 5-Hydroxytryptamine on Some Aspects of Hemorrhagic State in Radiation-Induced Thrombocytopenia.∗

Summary Synthetic serotonin (5-hydroxytryptamine-creatinine sulfate) increased vascular resistance and shortened the duration of traumatic bleeding in irradiated thrombocytopenic guinea pigs and mice, respectively. These effects were of short duration and were observed only when large doses of serotonin were given rapidly. Transient pulmonary distress was associated with the administration of effective doses to guinea pigs.