neuroscience I/V plots and the K+ reversal potential

KP-PC k.p.collins at worldnet.att.net%remove%
Mon Mar 24 00:14:13 EST 2003


The way I see it is that it's due to 'resting' background ionic
concentrations being maintained homeostatically - because it's so,
just so much variance can happen due to =any= 'pump' or gating
'event' - because the ionic dynamics 'want' to be at their
'set-points', overall - so a gating 'event' greates an ionic 'force'
that 'upsets the homeostasis teakettle', and the homeostasis becoming
locally-imbalanced 'reacts' with an opposing ionic 'force' that's
proportional to the divergence from homeostasis due to the gating
'event' - this reaction ionic 'force' reverses the gate's
flow-potential [and the actual ionic flow within it].

This way enables extraordinarily-powerful overall integration that's
at a 'deeper level' than, for instance, synaptic dynamics. [includes
all of the neural glia considerations that are briefly addressed in
AoK and which I've discussed in long-former posts here in b.n.]

This can be tested by playing with background ionic concentrations
in-vitro.

Cheers, Chrissy, ken

|"chrissy" <chrismin at bigpond.com> wrote in message
news:5fe998a3.0303232039.4d88fb39 at posting.google.com...
| I was recently looking at an I/V plot for K+ current in a neuron,
and
| the plot was a straight line with an x-intercept (zero current) at
| about -45mV.  I was told the K+ reversal potential is about -80mV,
so
| I assumed the voltage-gated K+ channel stopped current flow at that
| point, but I don't know enough about the properties of the K+
channel
| to be sure about that.  The K+ concentration inside and outside the
| cell was what a normal neuron would have.
| Was I wrong about the reason the K+ current stopped?  It sounds
like
| there's a better reason, but I don't know it...





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