Figure 4.

Elimination of picrotoxin sensitivity in GAD67 KO slices. A–C, Mean wave frequencies in control, picrotoxin, and CNQX measured in the septal nucleus (A), piriform cortex (B), and neocortex (C) of GAD67 KO slices. In contrast to control slices (Fig. 2), activity in KO slices shows minimal picrotoxin sensitivity, and is completely blocked by CNQX. The small degree of block of neocortical activity by picrotoxin may reflect a synthetic pathway for GABA in that region that does not depend on GAD67. D, E, Sample records showing lack of picrotoxin sensitivity and block by CNQX of waves in GAD67 KO slices. y-axis tick marks are 10% ΔF/F0.