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

Normalized Conductance vs. Voltage
Activation Tau Inactivation Tau


Bianchi (2012)

na3.mod

g = gbar * m^3 *h * s

Calculated from the model

 States  Tau

Activation

Voltage and Current Traces Normalized Conductance
Tau
 
  Activation: Vhalf = -16.6 (mV); k = -8.4 (mV)  

Inactivation

Voltage and Current Traces Normalized Conductance
  Inactivation: V1/2 = -53.7 (mV); k = 3.4 (mV)

Vladimirov (2012)

naf.mod

g = gbar * m^3 * h

Activation

Voltage and Current Traces Normalized Conductance Tau
  Activation: Vhalf = -21.5 (mV); k = -7.3 (mV)  

Inactivation

Voltage and Current Traces Normalized Conductance
  Inactivation: V1/2 = -62.4 (mV); k = 10.8 (mV)

Baranauskas (2006)

mcna1e.mod

Two-closed one-open state sodium channel model

Activation

Voltage and Current Traces Normalized Conductance Tau
  Activation: Vhalf = -26.8 (mV); k = -9.2 (mV)  

Inactivation

Voltage and Current Traces Normalized Conductance
  Inactivation: V1/2 = -71.9 (mV); k = 6.1 (mV)

Hoffman (1997)

g = gbar * m3 * h

Activation

Voltage and Current Traces Normalized Conductance Tau
  Activation: Vhalf = -10.7 (mV); k = -11.4 (mV)  

Inactivation

Voltage and Current Traces Normalized Cunductance
  Inactivation: V1/2 = -58.0 (mV); k = 5.0 (mV)

Payne

g = gbar * m3 * h

Activation

Voltage and Current Traces Normalized Conductance vs. Voltage Tau
  Activation: Vhalf = -29.9 (mV); k = -6.3 (mV)  

Inactivation

Voltage and Current Traces Normalized Conductance vs. Voltage
  Inactivation: V1/2 = -66.9 (mV); k = 7.2 (mV)

References: