0000000000122453
AUTHOR
C. Volk
Glial Protection Against Neuronal Damage
Glial homeostatic mechanisms are involved in neuronal protection during the early phase of cerebral ischemia. These protective effects include, among others, glutamate uptake and the regulation of pH in the extracellular space of the brain. Uptake of glutamate goes along with glial swelling, as does the elimination of protons from the glial cytosol. Five transport systems interact in order to maintain a normal intra- and extracellular pH in the brain.
Effects of Extracellular Acidosis on Glial Cell Intracellular pH: Evidence for a Glial Spatial H+-Buffering Mechanism?
Acidosis and in particular lactacidosis from anaerobic metabolism are considered of primary significance among the consequences of cerebral ischemia, seizures,, and head injury (Siesjo 1981). A marked decrease in brain tissue pH has been demonstrated in cerebral ischemia - even more so in hyperglycemic subjects - where lactic acid may accumulate to 20–30 mM and higher concentrations (Rehncrona et al. 1980; Katsura et al. 1991). Tissue pH may drop to pH 5.5 (Chopp et al. 1988). In consequence, acidosis has since long been suspected as a mediator of brain damage (Siesjo 1981).