# HH potassium channel model

Download the hhkchan.mod file into an empty directory.

## Part 1:

### On a PC . . .

Launch mknrndll from the icon in the NEURON program group.

> Navigate to the directory containing the desired mod files.
> Select "Make nrnmech.dll".

and the "mknrndll" script will create a nrnmech.dll file which contains the HHk model.

### On a unix workstation . . .

Go to the directory that holds the hhkchan.mod file and run the shell script

    	nrnivmodl

This will create a new executable called "special" which is a complete copy of NEURON and also includes the HHk model.

### Part 2:

Using the location of hhkchan.mod as the working directory, start NEURON with its standard GUI.

### On a PC . . .

> Under MSWin, double clicking on a hoc file opens that file using NEURON which automatically looks in the working directory for a nrnmech.dll file.
> Alternatively, you can launch nrngui from the icon in the NEURON program group and use NEURONMainMenu/File/WorkingDir or RecentDir to navigate to the directory containing the nrnmech.dll file.

### On a unix workstation . . .

> when you run the script nrngui in a working directory, it will automatically look for the special i.e. i686/special, that you created with nrnivmodl in the previous step. If it doesn't find one, it will execute the standard nrniv, which contains only the "built-in" mechanisms (hh, pas, IClamp etc..).

Bring up a single compartment model with surface area of 100 um2 (NEURON Main Menu / Build / single compartment) and toggle the HHk button in the Distributed Mechanism Inserter ON. Verify that the new HHk model (along with the Na portion of the built-in HH channel) produces the same action potential as the built-in HH channel (using both its Na and K portions).

NEURON hands-on course
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