The Effect of Acute Hypocapnia upon the Energy State of the Brain in Sustained Hyperammonemia

Abstract

The effect of acute hypocapnia upon the energy state of the brain tissue, exposed to sustained hyperammonemia, was evaluated in lightly anesthetized rats. The acute hypocapnia was associated with a mostly unaffected energy state of the frontal lobe. In the cerebellum and the brainstem there were inconsistent changes in the adenylates, indicating a more labile energy homeostasis, despite significantly lower ammonia contents compared with the cerebrum. The metabolism of α-ketoglutarate is discussed as a possible mediating mechanism for the toxicity of ammonia.

Key Words:

• Acute hypocapnia
• brain energy state
• hyperammonemia