NEURON Note #27
Goals: Create a model for the transient
voltage-gated sodium current (INaT)
Introduction:
The transient voltage-gated sodium current (INaT) is the key player
in the generation of action potentials. Four models are compared and one model
is created based on Magee et al's data (1995) and Baranauskas et al's data
(2006).
Notes about methods:
eNa = 85 (mV)
Results:
Summary
|
|
Bianchi
|
Vladimirove
|
Baranauskas |
Hoffman |
Payne
|
Magee
|
Baranauskas |
|
Activation Vhalf (mV)
|
-16.6 |
-21.5 |
-26.8 |
-10.7 |
-29.9 |
-30 |
-33.8 |
|
Activation k (mV)
|
-8.4 |
-7.3 |
-9.2 |
-11.4 |
-6.3 |
-6 |
-6.4 |
|
Inactivation Vhalf (mV)
|
-53.7 |
-62.4 |
-71.9 |
-58.0 |
-66.9 |
-67 |
-72 |
|
Inactivation k (mV)
|
3.4 |
10.8 |
6.1 |
5.0 |
7.2 |
7 |
6.8 |
Bianchi (2012)
na3.mod
g = gbar *
m^3 *h * s
Calculated from the model
Activation
 |
|
|
|
|
Activation: Vhalf = -16.6 (mV); k = -8.4 (mV) |
|
Inactivation
 |
 |
|
|
Inactivation: V1/2 = -53.7 (mV); k = 3.4 (mV)
|
Vladimirov (2012)
naf.mod
g = gbar *
m^3 * h
Activation
 |
 |
|
|
|
Activation: Vhalf = -21.5 (mV); k = -7.3 (mV) |
|
Inactivation
 |
 |
|
|
Inactivation: V1/2 = -62.4 (mV); k = 10.8 (mV)
|
Baranauskas (2006)
mcna1e.mod
Two-closed one-open state sodium channel model
Activation
 |
 |
|
|
|
Activation: Vhalf = -26.8 (mV); k = -9.2 (mV) |
|
Inactivation
 |
 |
|
|
Inactivation: V1/2 = -71.9 (mV); k = 6.1 (mV)
|
Hoffman (1997)
g = gbar * m3 * h
Activation
 |
 |
|
|
|
Activation: Vhalf = -10.7 (mV); k = -11.4 (mV) |
|
Inactivation
 |
 |
|
|
Inactivation: V1/2 = -58.0 (mV); k = 5.0 (mV)
|
Payne
g = gbar * m3 * h
Activation
 |
 |
|
|
|
Activation: Vhalf = -29.9 (mV); k = -6.3 (mV) |
|
Inactivation
 |
 |
|
|
Inactivation: V1/2 = -66.9 (mV); k = 7.2 (mV)
|
References:
- Bianchi D, Marasco A, Limongiello A, Marchetti C, Marie H, Tirozzi B, Migliore M.
On the mechanisms underlying the depolarization block in the spiking dynamics of
CA1 pyramidal neurons. J Comput Neurosci. 2012 Feb 5.
- Vladimirov N, Tu Y, Traub RD. Shortest Loops are Pacemakers in Random Networks
of Electrically Coupled Axons. Front Comput Neurosci. 2012;6:17. Epub 2012 Apr
3. PubMed PMID: 22514532; PubMed Central PMCID: PMC3324298.
- Baranauskas G, Martina M. Sodium currents activate without a
Hodgkin-and-Huxley-type delay in central mammalian neurons. J Neurosci. 2006 Jan
11;26(2):671-84. PubMed PMID: 16407565.
- Hoffman DA, Magee JC, Colbert CM, Johnston D. K+ channel regulation of signal propagation
in dendrites of hippocampal pyramidal neurons. Nature. 1997 Jun 26;387(6636):869-75.
- Magee JC, Johnston D. Characterization of single voltage-gated Na+ and Ca2+
channels in apical dendrites of rat CA1 pyramidal neurons. J Physiol. 1995 Aug
15;487 ( Pt 1):67-90. PubMed PMID: 7473260; PubMed Central PMCID: PMC1156600.
