부산대학교 도서관

Spreading depolarization (SD) is a feed-forward wave that propagates slowly throughout brain tissue and recovery from SD involves substantial metabolic demand. Presynaptic Zn release and intracellular accumulation occurs with SD, and elevated intracellular Zn ([Zn]i) can impair cellular metabolism through multiple pathways. We tested here whether increased [Zn]i could exacerbate the metabolic challenge of SD, induced by KCl, and delay recovery in acute murine hippocampal slices. [Zn]i loading prior to SD, by transient ZnCl2 application with the Zn ionophore pyrithione (Zn/Pyr), delayed recovery of field excitatory post-synaptic potentials (fEPSPs) in a concentration-dependent manner, prolonged DC shifts, and significantly increased extracellular adenosine accumulation. These effects could be due to metabolic inhibition, occurring downstream of pyruvate utilization. Prolonged [Zn]i accumulation prior to SD was required for effects on fEPSP recovery and consistent with this, endogenous synaptic Zn release during SD propagation did not delay recovery from SD. The effects of exogenous [Zn]i loading were also lost in slices preconditioned with repetitive SDs, implying a rapid adaptation. Together, these results suggest that [Zn]i loading prior to SD can provide significant additional challenge to brain tissue, and could contribute to deleterious effects of [Zn]i accumulation in a range of brain injury models.