number of channel

thats_karlo · Post by **thats_karlo** » Thu Apr 06, 2006 8:39 pm

Dear freinds,

Suppose, we have a single compartment model that we know
"g_ion (S/cm^2)", maximum conductance of a ion.

How can we determine the total number ofl channel for the ion?
Is it simply a multiplication of area*g_ion ?

If instead of condutance, we have permeability of the ion, how we can determine total number of channel?

Thank's in advance!

Karlo

Post by **ted** » Fri Apr 07, 2006 11:06 am

Conductance density is in units of conductance/area, so total conductance is the product
of area and conductance density. To find the number of channels required to produce that
total conductance, divide total conductance by the conductance per channel. The
arithmetic is similar if you are dealing with a current that is best described in terms
of permeability rather than conductance.

thats_karlo · Post by **thats_karlo** » Fri Apr 07, 2006 11:49 am

Hi Ted!

Thank you very much for your fast reply! I agree with you for calculation of number of channels when we have maximum conductance.

but when we have permeability value that has [cm/sec] units, what dose it mean
(maximum permeability in one compartment ) Pbar*Area (area of the compartment)?

is it a total permeability?!!!

Post by **ted** » Sun Apr 09, 2006 6:56 pm

Permeability of a patch of membrane is the product of the membrane area, channel density,
and permeability of a single channel. Channel density and single channel permeability can
be collapsed into a single value which has units of "permeability density", i.e.
permeability/area.