Effect of GGT-siRNA on high K+-induced Purkinje cell dendrite development. A) Rat cerebellar slices at DIV2 were pre-treated with GGTi-2147 (2.5 μM) or vehicle DMSO for 45 min, followed by the treatment with KCl (10 mM) for 2 hr. Membrane fractions were separated and subjected to IB with indicated antibodies. B) Quantification for the levels of membrane Rac, Rac (m). Data were shown as means ± SEM from three independent experiments. *P < 0.05. Student's t test. C) Representative images of Purkinje cells transfected with pSUPER or pSUPER-GGTβ-siRNA, without or with 10 mM KCl treatments. D, E) Quantification for the number of crossings at indicated distances from soma. F) Quantification for total dendritic length between neighboring circles. G) Total dendritic length between the circle of 50 and 75 μm. Data are shown as means ± SEM (n = 39 for control; n = 47 for GGT-siRNA; n = 36 for KCl; n = 34 for KCl with GGT-siRNA). N.S. P > 0.05; *P < 0.05; **P < 0.01; ***P < 0.001. Student's t test. Scale bar = 20 μm.