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Reversal potential/Equilibrium potential Definitions! (should be easy for you guys)

M. Tam mtam at mail.com
Tue Apr 29 01:13:08 EST 2003


As I understand it, the the "reversal potential" usually refers to the
electric potential at which there is no net ion flux through a particular
trans-membrane ion channel. For example, one might find an ACh receptor on a
post-synaptic neuron that does not change the membrane potential from rest
(resting equilibrium potential) when ACh is applied. But, if the cell is
depolarized or hyperpolarized, one might find that application of ACh
creates an inhibitory or excitatory effect, respectively. The resulting ion
flux would tend to bring the cell towards the reversal potential for that
channel.

Marcel Tam
mtam at u dot washington dot edu


"Dag Stenberg" <dag.stenberg at nospam.helsinki.fi.invalid> wrote in message
news:b8jja6$4u$1 at oravannahka.helsinki.fi...
> chrissy <chrismin at bigpond.com> wrote:
> > Just a simple question (hopefully):
> > What's the difference between the reversal potential and the
> > equilibrium potential for ion flow in neurons?
> > Both have to do with balancing electrical potentials, don't they?
>
> When a membrane opens its sodium channels to let in sodium ions, its
> potential starts to approach the equilibrium potential for sodium, which
> is inside positive. As the membrane potential reverses to inside
> positive, one talks about reversal potential.
>
> Dag Stenberg





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