Modelling spherical cell

Managing anatomically complex model cells with the CellBuilder. Importing morphometric data with NEURON's Import3D tool or Robert Cannon's CVAPP. Where to find detailed morphometric data.
Post Reply

Modelling spherical cell

Post by c.french »

I would like to model an isolated cell body (approximately spherical, no dendrites/axons) under voltage clamp conditions with fairly high channel densities. I suspect there will be conditions under which it is non-isopotential, and want to explore this. Has anyone done this?

Chris French
The Alfred Hospital
Site Admin
Posts: 5784
Joined: Wed May 18, 2005 4:50 pm
Location: Yale University School of Medicine

Post by ted »

I think Wil Rall did a theoretical analyais on something like this ~45
years ago for a sphere or cylinder and came to the conclusion that
nonisopotentialities collapsed within (much) less than a microsecond.
But what if diameter were, say, 0.1 AU or so . . .

Back to reality.

One might imagine three worst-case situations that would give rise
to inhomogeneous membrane potential in a spherical cell. The
trivial one is a cell-attached patch. The nontrivial ones are
  • a sphere with uniform properties that is subjected to an extracellular field
    a sphere with a cluster of ion channels that are localized to a small patch of membrane
NEURON can handle all of these.

Elevated or inhomogeneous cytoplasmic and/or extracellular resistivity
could contribute to inhomogeneities of membrane potential. Intra- and
extracellular structures, such as membrane-bound organelles or glia,
could restrict current flow in a way that makes Vm nonuniform.
Depending on geometry, this may or may not be suitable for NEURON--
you could be forced to use a field simulator that uses space-filling
finite elements instead of NEURON's cables.
Post Reply