[John Anderson 940401.16:30]
<[Bill Leach 940330.15:10 EST(EDT)]
It appears that some researchers have discovered a "new" brain cell that
has an interesting behaviour. When "triggered", this new cell releases a
gas that affects neurons in its immediate vicinity. I seem to remember
that the gas was something rather a bit surprising... like maybe
hydrogen-sulphide.
The gas is nitric oxide, NO. It is a free radical which, because it
is uncharged, can diffuse freely through the phospholipid bilayer
membranes that surround all biological cells, including neurons. It
was named "Molecule of the Year" by the journal Science in 1992
[Science (1992) 258:1862]. It is released by certain active neurons
and diffuses into other nearby cells where it binds and activates
guanylate cyclase, the enzyme that makes cyclic guanosine
monophosphate (cGMP). cGMP is a player in the initiation of a number
of processes that regulate the metabolism of cells. Among the
processes nitric oxide is possibly involved in is long-term
potentiation (LTP), the enhancement of the response of a neuron
brought on by repeated stimulation.
Sounds a great deal like this is physical evidence for a re-organizing
system to me!
LTP is thought by many to play a role in the establishment of
long-term memories... would this qualify as the sort of reorganization
you refer to? (I have not read the posts dealing with
reorganization.)
John
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John E. Anderson (anderson@cshl.org) 1 Bungtown Road
Beckman Neuroscience Center Cold Spring Harbor, NY 11724-2220
Cold Spring Harbor Laboratory FAX 516-367-8873