The Vomiting Center: Its Destruction by Radon Implantation in Dog Medulla Oblongata

Abstract

Slowly progressive lesions were effected in the interior of the medulla oblongata without injury to the periventricular gray substance by bilateral radon seed implantation in 13 dogs. Maximum tolerated initial radiation dosage was 0.4 mc./seed for gold implants and 0.015 mc./ seed for glass implants. Dogs with lesions placed accurately in the dorsolateral portion of the reticular formation did not vomit in response to intraven. administered apomorphine and were also refractory to large doses of copper sulfate given orally. One such animal survived for 220 days postoperatively. These findings confirm the earlier localization, by the authors, of the emetic center in the medullary reticular formation.