The Survival Period and Blood Pressures of Adrenalectomized Decerebrate Cats.

Abstract

In 1919 Bazett 1 described experiments on adrenalectomized cats showing that the time of survival after adrenal removal averaged 6 hours for decerebrate and 10 hours for lightly urethaned animals. Theoretically possible explanations, such as extra shock, hemorrhage, or pituitary injury in the case of the decerebrates, were advanced to explain this difference. It was emphasized that there was no immediate (within one hour) blood pressure fall even in animals surviving a few hours only. The present investigation to obtain experimental data to enable discrimination between the possible mechanisms for the more rapid death of the decerebrates, although so far unsuccessful in its aim, has disclosed facts pertinent to discussions in current literature.

Vincent and Thompson 2 , 3 reported that adrenalectomy in decerebrate cats permitted survival for only 1/2 to 1 hour although control decerebrates lived “for several hours”. Death in adrenalectomized animals was caused by respiratory failure due, they believed, to removal of an hormone (normally carried by the lymphatics to the medulla from the adrenals) which they named “pneumin”. In spite of the contradictory results of Florey, Szent-Gyorgi, and Florey, 4 Vincent and Thompson later reaffirmed their stand 5 although they increased the survival period to 1 to 2 hours after adrenalectomy They claimed that Florey et al. had based their criticism on too few experiments.

The adrenals in 30 cats, decerebrated by the Sherrington scoop method, have been removed at intervals varying from 1 to 18 hours after decerebration. Removal was by the lumbar route without asepsis. (In a few cases some antiseptic precautions were taken.) Death of adrenalectomized animals by respiratory failure was obtained only when: 1. the decerebration was unsatisfactory and itself a probable cause of death; 2. the trachea was occluded by mucus; 3. the animal had survived for at least several hours after adrenalectomy and was showing signs of circulatory changes.