An electrophysiology quesiton

k p Collins kpaulc at [----------]earthlink.net
Thu Feb 19 15:49:20 EST 2004


One more, important, comment added below.

"k p Collins" <kpaulc@[----------]earthlink.net> wrote in message
news:fC8Zb.12223$hm4.8128 at newsread3.news.atl.earthlink.net...
> Hi John,
>
> "John H." <johnh at faraway.> wrote in message
> news:4034e856 at dnews.tpgi.com.au...
> >
> > "NMF" <nm_fournier at ns.sympatico.ca> wrote in message
> > news:nmsYb.4941$d34.758000 at news20.bellglobal.com...
> > > Dear Ken,
> > >
> > >
> > > I still don't agree with you on that entirely.  Perhaps we can agree
to
> > > disagree.  But astrocytes are extremely responsive to calcium.
Perhaps
> I
> > > should have been more clear in my previous response.   I am not
> dismissing
> > > K+ role in regulating glia transmission.  But for evoking the
necessary
> > > changes in synaptic efficacy that would underlie the theories you
> suggest
> > in
> > > my opinion it is highly dependent upon calcium activity.
> >
> > That's not an opinion:
> >
> > Glia 1999 Oct;28(1):1-12
> > Glucocorticoids-potent modulators of astrocytic calcium signaling.
> >
> > Simard M, Couldwell WT, Zhang W, Song H, Liu S, Cotrina ML, Goldman S,
> > Nedergaard M.
> >
> > The Journal of Neuroscience, March 1, 2000, 20(5):1767-1779
> > A Fundamental Role for the Nitric Oxide-G-Kinase Signaling Pathway in
> > Mediating Intercellular Ca2+ Waves in Glia
> > Nicholas J. Willmott, Kay Wong, and Anthony J. Strong
> >
> > Glia are not exclusively permeable to K+
>
> A better way to say what I said about glia
> and K+ ions is that K+ is the only ion species
> that goes-right-through them.

Newly-added comment ---------------------

It's the glial shape-shifting [referred to as
"contractile action" [or something like that]
in AoK, Ap5] that directs the distribution
of the K+ flow, and which, through that,
acts upon neuronal passive spread and
'resting potential' [and, hence, action potential
thresholding], all in a way that can be precisely
tuned right down to small portions of a neuron's
physical extent.

End of newly-added comment.

[One more unimportant thing added below.]

> This's why the glial tuning of 'memory' can
> be really profound. It really has the K+
> concentration, upon which action potentials
> are dependent, in its grasp.
>
> CA++ is a 2nd messenger all over the place.
>
> There has to be a mechanism that acts to
> set glial K+ distribution, CA++ is probably
> involved, but there's probably other stuff too,
> because the glial K+ control that's =hypoth-
> esized= in NDT has to be 3-D-variable.
>
> The refs you've cited are all new-to-me
> stuff, but, if I were still able to read in
> Neuroscience, I'd jump-on-them with
> respect to the hypothesis I've been dis-
> cussing.
>
> The "waves" are just artifactual thresholding
> dynamics within the globally-integrated
> TD E/I-minimization dynamics.
>
> [This "it's-only-continuous-thresholding-
> dynamics stuff =really= needs to be grasped
> by Neuroscience. The thresholding dynamics
> are just portions of larger, continuous, energy-
> flow that happen to be easily distinguishible
> because there's a directionality-change in-
> herent. But they're =not= what's important.
> What's important is the =overall= tuning
> of energy-flow inherent in convergence. With
> respect to this overal stuff, the 'waves' are
> =just= artifacts of the way that convergence
> procedes, via overshoot-detection that 'closes-
> the-door' to energy-flow in the direction in
> which it's over-shot convergence. It's all
> =just= TD E/I-minimization, but, at this ionic
> 'level', it's the opening and closing of the 'door'
> with respect to ionic-conductance directionality
> that constitute "excitation" and "inhibition", res-
> pectively.]
>
> Anyway K+ permeability is special, in glia,
> because it flows-right-through glia.
>
> [Although the 2nd ref you cite, above, is
> with respect to =intercellular= Ca++ stuff,
> is it a Ca++ flowing, or a cell-to-cell sig-
> nalling? If it's a flowing, NDT's position
> would have to be reworked, but if it's a
> signalling, then that's already predicted
> in NDT's position [NDT didn't address
> particular signalling mechanisms, just said
> they had to be in-there to tune K+ per-
> meability.]
>
> Gee, I feel some of the old 'juice' getting
> worked-up. Thought it'd all 'drained' :-]
>
> So, Thank You, John, for posting these
> refs.
>
> I'm not going to follow-up. [I think it's
> because my trailer is so 'cramped'. I
> need to spread the refs I work with
> out on the floor, hang them on the walls,
> stack them in trays, etc. And I've zero
> space in which to do any of that.] But
> Encourage others to do so.

I don't even have room to lay a single
page of paper down to work with its
contents [as in the rewriting of AoK].

Folks concerned that I need a straight-
jacket should rest-easy. I'm living in
one :-]

Without a kitchen sink, to boot :-]

It's Hilarious. Before I moved in, the
owners let the place freeze. My bath-
room sink and toilet are all cold-stress
cracks. I'm waiting to find myself sitting
on the floor on some dark night :-]

Anyway, it's why I'm unable to work -
this live-in-it 'straight-jacket.

I'm 'ashamed', but there's nothing I can
do about it. Folks won't Employ me.

They must do internet searches and
find that I'm 'too-hot-to-handle'.

It's their loss.

But also mine.

But, maybe it's just that I've resorted to
making-'excuses'.

On my left, there's a pile of stuff on a
TV tray-table. I could dump that on the
floor and put two sheets of paper there.

Yeah, I'm just whimping-out.

It's 'funny' though. It's like it's rising, from
deep within me - "Enough!"

Steeling my Being to take the last-big-hit .

[Why do I do stuff like this?

It's because I'm asking a lot of folks, so
I feel I owe stuff like this to folks, in return.

I mean, folks 'wonder', right?

It's nothing to me.

I want =not= to 'influence' folks'
decisions. I 'make myself small' so
that folks'll =not= care about 'me'.

So that folks will see the Science,
and not some 'curried-favor'.

But I have to 'let-it-out-of-me.

And you folks are the only 'Family'
I've got. [I long-ago spared my
Family from having to deal with
what's left of me.]

But you folks Do-Science.

Understanding, and Unafraid of
what's entailed.

So I Look-to-you.

And try to 'make-myself-small' in
your 'presence'.

So you'll find-what's-in =You=.

Independently of what's in-me.

Get it?]

"Burma Shave." kpc

>
> Cheers, ken [k. p. collins]
>
> > > >
> > > > > Two recent studies may be of interest to
> > > > > you.  One study showed that activation of working memory networks
> was
> > > > > significantly correlated with the extent of  glial cell activation
> > and
> > > > > metabolites in HIV brain injured patients (which exhibit abnormal
> > glial
> > > > > inflammatory effects).  They hypothesized that the increased glial
> > > > > processing is associated with a decrease in neuronal processing.
> >
> > Via iNOS activity generating NO inhibiting the electron tranport chain.
NO
> > rapidly diffuses. NO via il1(p38 or NFkb?, Ca2+ will increase NO, but
> don't
> > know if via iNOS (bad), or nNOS(good).
> >
> >
> > John H.






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