This is the readme for the model associated with the paper

Chen BS, Lo YC, Liu YC, Wu SN. Effects of transient receptor
potential-like current on the firing pattern of action potentials in
the Hodgkin-Huxley neuron during exposure to sinusoidal external
voltage. Chinese Journal of Physiology 2010; 53(6):423-429.

Abstract: 

Transient receptor potential vanilloid-1 (TRPV1) channels play a role
in several inflammatory and nociceptive processes. Previous work
showed that magnetic electrical field-induced antinoceptive action is
mediated by activation of capsaicin-sensitive sensory afferents. In
this study, a modified Hodgkin-Huxley model, in which TRP-like current
(I-TRP) was incorporated, was implemented to predict the firing
behavior of action potentials (APs), as the model neuron was exposed
to sinusoidal changes in externally-applied voltage. When model neuron
is exposed to low-frequency sinusoidal voltage, increased maximal
conductance of I-TRP can enhance repetitive bursts of APs accompanied
by a shortening of inter-spike interval (ISI) in AP firing. The change
in ISIs with number of interval is periodic with the phase-locking. In
addition, increased maximal conductance of I-TRP can abolish chaotic
pattern of AP firing in model neuron during exposure to high-frequency
voltage. The ISI pattern is converted from irregular to constant, as
maximal conductance of ITRP is increased under such high-frequency
voltage. Our simulation results suggest that modulation of TRP-like
channels functionally expressed in small-diameter peripheral sensory
neurons should be an important mechanism through which it can
contribute to the firing pattern of APs.

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To run the models:
XPP: start with the command
xppaut HH-Vext.ode

On selecting Initialconds -> (G)o, this simulation will make a graph
similar to Figure 2a in the paper:



Changing the parameter value of gtrp and re-running will make a graph
similar to Figure 2b.  Notably, the value of gK should be 36 mS/cm^2.

Bard Ermentrout's website http://www.pitt.edu/~phase/
describes how to get and use xpp.

This model file was submitted by:

Dr. Sheng-Nan Wu
Department of Physiology
National Cheng Kung University Medical Center
Tainan City, 70101, Taiwan
snwu@mail.ncku.edu.tw