De Schutter: Purkinje Cell Model
|Figure 1: ||Activation and inactivation properties of the delayed rectifier
current (Kdr, —) in the model. Seady-state activation and inactivation
vs. voltage are plotted at the left, the time constants of activation and
inactivation(τm and τh) 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. The voltage clamps 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.|
Delayed Rectifier (Kdr)
The Purkinje cell delayed rectifier (Kdr) is responsible for the repolarization of
somatic action potentials. Whole-cell voltage-clamp recordings (Fig. 9 in ) and
patch-clamp recordings (Fig. 9 in ) of the Kdr current are available but
incomplete. The I - V relations of the currents in both reports are very similar.
In the current model we have used the published equations for Kdr current in
bullfrog sympathetic ganglion cells  because both the I - V curve and the
steady-state inactivation (Fig. 2E) of the bullfrog data are comparable with the
data from .
 B Gähwiler and I Llano. Sodium and potassium conductances in
somatic membranes of rat purkinje cells from organotypic cerebellar
cultures. Journal of Physiology (Lond.), 417:105–122, 1989.
 T Hirano and S Hagiwara. Kinetics and distribution of voltage-gated
Ca, Na, and K channels on the somata of rat cerebellar Purkinje cells.
Pfluegers Archiv, 413:463–469, 1989.
 Koch C Yamada W and Adams P R. Multiple channels and calcium
dynamics. In Koch C and Segev I, editors, From Synapses to Networks,
pages 97–133. MA: MIT Press, 1989.