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 .|
Anomalous Rectifier Current (Kh)
Inward rectification has been shown to be present in the Purkinje cell [1, 3] and a
channel permeable to K+ and activated at hyperpolarized potentials has been
identified in single-channel recordings (, 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 . These equations have the same activation curve (Fig. 20) as the
voltage-clamp data from a single Purkinje cell shown by  (their Fig.
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 DL Gruol, VE Dionne, and AJ Yool. Mutliple voltage-sensitive K+
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