Figure 1.

Highly Reliable Spike Propagation along Purkinje Cell Axons Is Secured by Node of Ranvier IK Channels

(A) Schematic of experimental configuration.

(B) Simultaneous whole-cell somatic and cell-attached axonal recordings of a spontaneously firing Purkinje cell in response to a somatic current ramp injection (2 nA). ^∗Differentially propagated spike.

(C) Maximal firing frequencies at soma (292 ± 19 Hz, n = 19), main axon (257 ± 17 Hz, n = 9, includes data from Monsivais et al., 2005), and axon collateral (253 ± 14 Hz, n = 19).

(D) Local drug application (green bars) to branchpoint during whole-cell somatic recording (black) and cell-attached axonal recordings (blue) downstream of the targeted branchpoint. Baseline firing rate is indicated above somatic traces.

(E) Averaged whole-cell somatic and cell-attached spikes before (blue), during (green), and after (gray) drug application.

(F) Spike amplitude before (blue, a1) and during (green, a2) drug application.

(G) Data summary of axonal spike suppression.

p < 0.0001 for TRAM 1 μM, 0 Ca²⁺, Ni²⁺, p < 0.005 TRAM 500 nM, p < 0.002 TTX. TEA, HBS not significantly different from baseline (Student’s t test). Error bars, ±SEM.