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ion channels - resonance frequency?

John H. johnhkm at netsprintXXXX.net.au
Mon May 1 13:49:20 EST 2000


Looking for other matters yesterday, I stumbled across this:


[[28/04/00 23:17

J Cell Biochem 1998 Sep 1;70(3):297-303 Related Articles, Books, LinkOut


Magnetic field activation of protein-DNA binding.

Lin H, Han L, Blank M, Head M, Goodman R

Department of Pathology, Columbia University Health Sciences, New York, New
York 10032, USA.

The mechanisms involved in sensing, signaling, and coordinating changes
resulting from magnetic field-induced stress show substantial similarities
to those of heat shock, e.g., magnetic field-induced heat shock 70 gene
(HSP70) expression involves heat shock factor (HSF) activation and heat
shock element binding. However, an additional requirement for
transactivation of HSP70 expression by magnetic fields is the binding of Myc
protein, indicating that additional elements and/or pathways are involved in
the induction of HSP70 expression by magnetic fields. To investigate the
possible participation of additional genetic elements in magnetic
field-induced HSP70 expression, we examined both magnetic field exposure and
heat shock on protein-DNA binding of the transcription factors HSF, AP-1,
AP-2, and SP-1 in four human cell lines. The binding sites for these
transcription factors are present in the HSP70 promoter. AP-1 binding
activity, normally not increased by heat shock, was increased by magnetic
fields; heat shock induced an increase only in HSF binding. Although
intersecting and converging signaling pathways could account for the
multiplicity of elements involved in magnetic field-induced HSP70
transcription, direct interaction of magnetic fields with DNA is also a
possible mechanism. Because magnetic fields penetrate the cell, they could
well react with conducting electrons present in the stacked bases of the
DNA.

PMID: 9706866, UI: 98370363

John H.
Remove 4x
Kaushik Ghose <kghose at wam.umd.edu> wrote in message
news:Pine.GSO.4.21.0004302334001.12842-100000 at rac7.wam.umd.edu...
> Hi,
> This is an interesting idea. Assuming that the electrically operating
> channels mentioned refer to voltage gated channels we can approach the
> problem this way :
>
> THe voltage gated channels are operated by a voltage difference between
> the inside of the neuron and the outside. THis voltage diference typically
> has to be of a certain magnitude and also has to exist for a certain time
> before the channel can open.
>
> If we consider the brain matter to be a conducting mass
> (extracellular medium) filled with semi-insulated strands of wire
> (neurons) then passing radio waves through this mass can possibly induce
> currents in the strands of wire.
>
> But radio frequencies are fairly high (in the order of MHz and at least
> KHz) and so the cycle of the induced currents (if they existed) would be
> too short to set off these channels.
>
> What is done is to use much lower frequencies - actually DC pulses - and
> disguise the radio transmitter as a large magnetic coil - and the result
> is TMS or transcranial magnetic stimulation with which people are getting
> very interesting results.
>
> But the technique is new, and because it is not very well localised
> (stimulating one part of the brain often affects a large region) results
> obtained with it are controversial.
>
> thanks
>
> Kaushik Ghose
> Graduate Student
> Programme in Neurosciences and Cognitive sciences
> University of Maryland College Park
>
> On Thu, 20 Apr 2000 kyan1 at hofstra.edu wrote:
>
> > hi group,im thinking that, since ion channels operate electrically,there
> > could exist some resonance frequencies of electro-magnetic waves such
that
> > the channel activity is altered,e.g. forced to open/closed states.  If
these
> > frequencieshappens to be in the radio range,  then they could
beexploited,
> > say,  for use in non-invasive stimulation.has any research been done re
this
> > topic? thanks:)kyan1 at hofstra.edu
> >
> >
> > Sent via Deja.com http://www.deja.com/
> > Before you buy.
> >
>








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