Fig. 5.

Inhibition of VSOACs inhibited the calcium-independent release of glutamate. All data were collected from brain slices incubated in 0-Ca²⁺–EGTA solution for at least 20 min before the start of the experiment. A, Representative HPLC measurements of glutamate release in the superfusate before and during SD in two separate brain slices. The initial onset of SD was measured using intrinsic optical signals and is taken as t = 0. SD propagated throughout the brain slice during the collection of superfusate and induced the release of glutamate, even in the 0-Ca²⁺–EGTA solution. Preincubation with NPPB (100 μm) reduced the release of glutamate during spreading depression. B, Effect of NPPB on glutamate, GABA, and glutamine release during spreading depression. Each point represents the increase in the indicated amino acid 7 min after the initiation of spreading depression from at least n = 5 separate brain slices. All numbers are expressed normalized to the initial levels before spreading depression. NPPB significantly depressed the release of only glutamate during SD (*p < 0.01) and had no effect on the release of either GABA or glutamine.