Figure 8.

Reduction of IPSC amplitude in DCNs by local application of penitrem A to Purkinje cell axons. A, Schematic diagram showing the experimental setup. B, Prediction of the effect of penitrem A. Blocking axonal BK channels would augment the propensity of failures of APs in the axon. Because single DCN neurons receive inputs from multiple Purkinje cell axons, occasional failures of axonal APs would translate to a reduction of the amplitude of IPSCs rather than their failures. C, IPSCs recorded from DCN neurons before (Control) and after the application of penitrem A to the white matter away from DCNs. Values were normalized to the first phasic IPSC in control. The blocker significantly reduced the overall amplitude of IPSCs evoked at 100 Hz. IPSCs recovered after a 5 min washout (p = 0.05 with 2-way ANOVA between Control and Penitrem A, n = 10). *p < 0.05 with post hoc analysis between Control and Penitrem A.