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De Schutter: Purkinje Cell Model


Figure 1: Activation and inactivation properties of the anomalous rectifier current (Kh, —) in the model. Seady-state activation vs. voltage are plotted at the left, the time constants of activation (τ1 and τ2,) vs. voltage in the middle (Note: Semilogarithmic scale), and a simulation of representative voltage-clamp currents at the right, obtained from a spherical cell and assuming a complete block of all other channels. They simulate steps from a holding potential of -110 to -70 mV up to 0 mV in 10 mV increments. The voltage-clamp current amplitude has been scaled arbitrarily because we mainly wanted to demonstrate the current kinetics. Note: This current does not inactivate and that activation is determined by 2 time constants [4].

Anomalous Rectifier Current (Kh)

Inward rectification has been shown to be present in the Purkinje cell [13] and a channel permeable to K+ and activated at hyperpolarized potentials has been identified in single-channel recordings ([2], K8). However, kinetic information on this channel for the Purkinje cell is incomplete. Accordingly, we have used the equations for the anomalous rectifier (Kh) in cortical neurons published by [4]. These equations have the same activation curve (Fig. 20) as the voltage-clamp data from a single Purkinje cell shown by [1] (their Fig. 2).


[1]   F Crepel and J Penit-Sorie. Inward rectification and low threshold calcium conductance in rat cerebellar purkinje cells. Journal of Physiology (Lond.), 372:1–23, 1986.

[2]   DL Gruol, VE Dionne, and AJ Yool. Mutliple voltage-sensitive K+ channels regulate dendritic excitability in cerebellar purkinje neurons. Neuroscience Letters, 97:97–102, 1989.

[3]   J Hounsgaard and J Midtgaard. Intrinsic determinants of firing patterns in Purkinje cells of the turtle cerebellum in vitro. Journal of Physiology (Lond.), 402:731–749, 1988.

[4]   Schwindt P C Spain W J and Crill W E. Anomolous rectification in neurons from cat sensorimotor cortex in vitro. Journal of Nerurophysiology, 57:1555–1576, 1987.