Pulmonary Edema and Hemorrhage From Preoptic Lesions in Rats

Abstract

Fatal hemorrhagic edema of the lungs was produced in rats by discrete electrolytic lesions of the rostral hypothalamus. Edema was confirmed by gravimeteric procedures and both gross and histological study of the lungs. Hyperthermia, a common concomitant of rostral hypothalamic injury, was eliminated as an essential contributory factor to the edema. The effective lesions were bilaterally situated at the lateral tips of the rostral 1/3 of the optic chiasm. In a few animals, more caudally placed lesions in the mid-line destroying the periventric-ular system produced lung edema. The suggestion is offered that such lesions interrupt descending pathways from the critical preoptic region. Neither lesions bordering the preoptic region nor unilateral preoptic lesions produced pulmonary edema.