Hypoxia brain, metabolic adaptations

Brain Microvascular and Metabolic Adaptation to Proionged Mild Hypoxia... 

Hochachka, P.W., C.M. Clark, C. Monge, C. Stanley, W.D. Brown, C.K. Stone, R.J. Nickels, and J.E. Holden. (1996b). Sherpa brain glucose metabolism and defense adaptations against chronic hypoxia. J. Appl. Physiol. 81 1355-1361. Hochachka, P.W., H.C. Gunga, and K. Kirsch (1998). Our ancestral physiological phenotype An adaptation for hypoxia tolerance and for endurance performance Proc. Natl. Acad. Sci. USA 95 1915-1921. 

Prolonged hypoxia causes an increase in the concentration of the glucose in the brain (150% of control) and lactate (250% of control) and a decreased glycogen (75% of control) (25). The regional metabolic rate for glucose is also increased by 10-40% however, ATP and phosphocreatine content, as well as intracellular pH, were unchanged consistent with the notion that adaptation was successftil (25). A... 

Metabolic data from fetal brain studies indicate that moderate hypoxia or asphyxia can be adapted to by increases in cerebral blood flow and/or fractional oxygen extraction (15,111,135-138). Acutely, reductions in cerebral oxygen consumption are small eompared to the reduction in arterial oxygen content (34) however, during severe or prolonged asphyxia, reductions in cerebral oxygen consumption become apparent. 

---