Acute and Chronic Hyperosmolality

Abstract
Acute and chronic elevations in osmolality were induced in rats and mice. After 48 and 96 hours of hyperosmolality, rat brain glutamine concentration increased to between 210% and 230% of control. This increase may account for 20% of the previously postulated idiogenic osmols that enable the brain to resist volume changes. Cerebral metabolic rates were reduced in the brains of mice made acutely and chronically hyperosmotic in spite of normal levels of adenosine triphosphate and phosphocreatine.