The Role of Na+/Ca2+ Countertransport and Other Na+-Entry Routes in the Pathophysiology of Stroke

摘要: Na+ has a crucial role in neuronal osmoregulation and, therefore, its intracellular concentrations are strictly controlled by several homeostatic systems, the most important of which is Na+/K+ ATPase. A marked increase [Na+]i takes place after ischemic insults neurons where it triggering necrotic perhaps, also apoptotic cell death. While impairment ATPase activity contributes to this process, not sufficient per se cause massive overload observed ischemia requires, instead, significant influx into or an efflux. Traditionally, permeability occurring was ascribed activation voltage-gated channels and/or glutamate receptors, and their pharmacological blockade proposed as therapeutic strategy stroke but did meet expectations. More recently, spotlight turned on NCX, ASICs, NHE, NKCC, group ion transporters, which, because specific mechanisms activation, could represent preferential efflux route neurons. Evidence suggesting involvement possible benefits modulation condition reviewed present chapter.