Figure 1.

Effects of gabapentin on cortical spreading depression (CSD) susceptibility assessed by electrical stimulation (A) or topical KCl application (B). (A) Representative tracings showing direct cortical stimulation using cathodal square pulses (dots) of escalating intensities and alternating polarity until a CSD is triggered. Gabapentin significantly elevated the electrical threshold for CSD induction. The complete dataset is shown in the lower panel, where each data point represents one animal. Please note the logarithmic vertical axis scale. See Table 1 for median and interquartile ranges for electrical CSD thresholds. ^*P<0.05 versus saline. (B) Representative extracellular microelectrode recordings of repetitive CSDs triggered during 1 hour topical KCl application (1 mol/L). E1 and E2 are the proximal and distal recording electrodes, placed in line with the KCl application window, 2 and 4 mm away, respectively. Gabapentin decreased the number of CSDs triggered by KCl. Fewer CSDs were usually detected by the distal electrode than the proximal one, suggesting propagation failure, which did not significantly differ among treatment groups (Table 1). Group means are shown as horizontal lines. Scale bars apply to both A and B. ^*P<0.05 versus saline. GPT, gabapentin.