Further Studies With Serotonin and Experimental Pulmonary Embolism*

Abstract

Purified extract of serotonin, crude extract of serotonin from fresh blood clots, and multiple small fresh blood clots all produce a similar picture in the dog of pulmonary hypertension, peripheral hypotension, hyperpnea, bradycardia and defecation. The effects of serotonin are variable and unpredictable. Heparin in clinical doses exerts a protective effect in dogs to infusion of serotonin and to multiple small fresh blood clot in 94 per cent. It is recommended that intravenous heparin in 5,000-unit doses be given as an emergency measure in pulmonary embolism.