Ca

Description: Calcium channel

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Introduction

Catterall, 2000). Voltage-gated calcium channels (VGCCs), heteromultimeric protein complexes consisting of an alpha1 sub- unit, as well as ancillary beta, alpha2-delta, and possibly gamma subunits (Hofmann et al., 1994), are a primary route through which calcium can enter cells. The alpha1 subunit forms the ion conducting pore and contains the ion selectivity filter and voltage sensors which gate the channel in response to changes in membrane potential (Hofmann et al., 1994). Auxiliary beta and alpha2-delta subunits modulate channel kinetics and targeting of the alpha1 subunit to the membrane (Neely et al., 1993; Tareilus et al., 1997; Yasuda et al., 2004). VGCCs are encoded by 10 genes, four of which encode the L-type calcium channel family and include Cav1.1, Cav1.2, Cav1.3 and Cav1.4 (Ertel et al., 2000). These channels are highly sensitive to 1,4- dihydropyridines, phenylalkylamines and benzothiazepines, display slow inactivation kinetics, and have a high voltage activating threshold (Tsien et al., 1987; Catterall, 2000). (From Peloquin [232], upload of papers in due course)

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Biophysics

Model Generic Ca (ID=8)

Animal	rat
CellType	Neocortical L5PC
Age	0 Days
Temperature	35.0°C
Reversal	50.0 mV
Ion	Ca +
Ligand ion
Reference	[256] I Reuveni et. al; J. Neurosci. 1993 Nov
mpower	2.0
m Alpha	(0.055*(-27-v))/(exp((-27-v)/3.8) - 1) If v neq -27
m Beta	(0.94*exp((-75-v)/17))
hpower	1.0
h Alpha	(0.000457*exp((-13-v)/50))
h Beta	(0.0065/(exp((-v-15)/28)+1))

MOD - xml - channelML

Model Ca_LVA (ID=46)

Animal	rat
CellType	Hippocampal CA3 PC
Age	0 Days
Temperature	34.0°C
Reversal	131.04 mV
Ion	Ca +
Ligand ion
Reference	[257] R B Avery et. al; J. Neurosci. 1996 Sep 15
mpower	2.0
m Inf	1.0000/(1+ exp((v - -30.000)/-6))
m Tau	(5.0000 + 20.0000/(1+exp((v - -25.000)/5)))/qt
hpower	1.0
h Inf	1.0000/(1+ exp((v - -80.000)/6.4))
h Tau	(20.0000 + 50.0000/(1+exp((v - -40.000)/7)))/qt

References

232

Peloquin JB et al. Temperature dependence of Cav1.4 calcium channel gating.
Neuroscience, 2008 Feb 19 , 151 (1066-83).

256

Reuveni I et al. Stepwise repolarization from Ca2+ plateaus in neocortical pyramidal cells: evidence for nonhomogeneous distribution of HVA Ca2+ channels in dendrites.
J. Neurosci., 1993 Nov , 13 (4609-21).

257

Avery RB et al. Multiple channel types contribute to the low-voltage-activated calcium current in hippocampal CA3 pyramidal neurons.
J. Neurosci., 1996 Sep 15 , 16 (5567-82).

321

Nusser Z Variability in the subcellular distribution of ion channels increases neuronal diversity.
Trends Neurosci., 2009 May , 32 (267-74).

340

Randall AD et al. Contrasting biophysical and pharmacological properties of T-type and R-type calcium channels.
Neuropharmacology, 1997 Jul , 36 (879-93).

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Credits

Contributors: Rajnish Ranjan

To cite this page: [Contributors] Channelpedia https://channelpedia.epfl.ch/wikipages/190/ , accessed on 2024 Dec 21

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