Consciousness, New Thinking About

Matt Jones jonesmat at physiology.wisc.edu
Tue Jun 11 10:36:26 EST 2002


"John H." <John at overhere> wrote in message news:<YJ0N8.1358$Fr.55930 at ozemail.com.au>...

> 
> Hippocampus very susceptible to a wide variety of insults, complicating
> factors being: high GC receptor relative to MR receptors,  highest density
> of NMDA receptors which are implicated in EAA damage and NO production via
> the endocytosis of the receptors


John,

What are GC and MR receptors?




> 
> Your statement re preferential damage to hippocampal Gaba neurons is very
> interesting. If you can provide a reference appreciated because I have noted
> other references to the effect of other 'distance effects' of trauma. The
> loss of Gaba neurons is interesting because it raises interesting questions
> with respect to the symptoms of some individuals post head trauma who
> sometimes report symptoms not consistent with the observed physical injury.



The paper I was mainly thinking of is the first one below. The rest
are later papers that expand on the issue of percussive injury-related
loss or changes distant from the injury site. The story is still
evolving. Often observed are losses of interneurons, but
paradoxically, enhancement of inhibitory postsynaptic event frequency.
Even more paradoxically, this increase in inhibition can lead to
hyperexcitability (! - see paper by Chen). "inhibition" turns out not
to be a perfect description of what GABAergic systems are up to...


Cheers,

Matt





Toth Z, Hollrigel GS, Gorcs T, Soltesz I.
Instantaneous perturbation of dentate interneuronal networks by a
pressure wave-transient delivered to the neocortex.
J Neurosci. 1997 Nov 1;17(21):8106-17.

Ross ST, Soltesz I.	
Selective depolarization of interneurons in the early posttraumatic
dentate gyrus: involvement of the Na(+)/K(+)-ATPase.
J Neurophysiol. 2000 May;83(5):2916-30.

Chen K, Aradi I, Thon N, Eghbal-Ahmadi M, Baram TZ, Soltesz I.	
Persistently modified h-channels after complex febrile seizures
convert the seizure-induced enhancement of inhibition to
hyperexcitability.
Nat Med. 2001 Mar;7(3):331-7.

Santhakumar V, Ratzliff AD, Jeng J, Toth Z, Soltesz I.	
Long-term hyperexcitability in the hippocampus after experimental head
trauma.
Ann Neurol. 2001 Dec;50(6):708-17.

Ratzliff AH, Santhakumar V, Howard A, Soltesz I.
Mossy cells in epilepsy: rigor mortis or vigor mortis?
Trends Neurosci. 2002 Mar;25(3):140-4. Review.




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