The pulmonary edema produced by electrolytic lesions of the lateral pre optic area (POA) of the hypotalamus can be reproduced by kainic acid (KA) microinfused in the POA of rats. KA group and electrolytic group showed similar patterns of lung pathology on gross and microscopic examination. The arterial blood pressdre and the frequency of discharge from the greater splanchnic nerve in KA group was increased more severely than in electrolytic group.The data indicate that there is a special and close ralation between lesion of POA and development of pulmonary edema. They also suggest that the changes in hemodynamics may not be a major factor in mechanisms of neurog enic pulmonary edema.