Homeostasis of mitochondrial calcium is disturbed in the cerebellum but not in other brain areas during chronic hyperammonemia

We studied the effects of chronic hyperammonemia, which was induced by consumption of ammonium acetate with food, on homeostasis of mitochondrial calcium in the neocortex, cerebellum, hippocampus, and striatum of rats. We found that in cerebellar mitochondria chronic moderate hyperammonemia results in an increase in the content of endogenous calcium and a decrease in the calcium capacity, rate of Ca2+ uptake, and the rates of Na-dependent and hydrogen peroxide-dependent Ca2+ release. Thus, only cerebellar mitochondria in vivo are sensitive to food salts of ammonium and hyperammonemia leads to damage of the mitochondrial system of Ca2+ transport only in the cerebellum.