www.neuron.yale.edu

I used the channel builder to build a Q type calcium channel. I had selected 'Create new type' for 'Selective for ion...' and used the GHK equation. When I tested the channel with a single compartment model, it worked fine. But once I saved it in a session file and tried to load the session file again I kept getting the error message,

[i]nrniv: NonSpecific_ion is not an ion mechanism
in D:/John/PhD/Project/MSP Wolf 2005/Garage/temp.ses near line 15
{genprop.set_data("CaQ", 1, 0, 8, "ca")}
^
ChannelBuildSelectProperties[0].ion_charge"NonSpecific_ion" )
ChannelBuildSelectProperties[0].set_useionstr )
ChannelBuildSelectProperties[0].set_namestr )
ChannelBuildSelectProperties[0].set_data"CaQ"108"ca" , , , , )[/i]

I am surprised because I didn't select 'Non-specific ion' at all. I notice that this problem keeps coming if I choose the GHK option in the channel builder irrespective of the ion.

Can someone please help me with this problem?

You may have run into a bug. If so, there is a possibility that it has already been
fixed. What version of NEURON are you using?

I am using Neuron version 5.8.88..

I was able to reproduce the problem with 5.8.88. It was fixed in the alpha version I picked
up from the CVS repository late last week. I see that a new set of alpha version installers
is now available; why don't you get one of those from
http://www.neuron.yale.edu/ftp/neuron/versions/alpha/
and see if that doesn't take care of it?

Yes the 5.9 alpha version does take care of it. The bug is not there in the versions prior to 5.7 either. Also I could fix the problem in version 5.8 by interchanging the positions of the following statements in the chanbild\properties.hoc file within the set_data function.

selion(iontype_, $s5)
set_namestr()

thank you