I just noticed that medscape (www.medscape.com) now gives free Medline
searches. I stumbled on the following abstract that may be of some interest
to the list.
Please note that thioctic acid is the same thing as Lipoic acid which can be
found at any nutrition center. It is considered to be a very powerful
antioxidant which crosses the blood brain barrier and recycles vitamin E.
Can anyone clarify the mention of the R and S isomers and how they relate to
the Lipoic acid we little people buy.
Ron Reiner (48 + 1yr)
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The isomers of thioctic acid alter C-deoxyglucose incorporation in rat
basal ganglia.
Title Abreviation: Biochem Pharmacol
Date of Pub: 1996 Apr 12
Author: Seaton TA; Jenner P; Marsden CD;
Abstract: Nigral cell death in Parkinson's disease is associated with
decreased reduced glutathione (GSH) levels, impaired complex I
activity and inhibition of alpha-ketoglutarate dehydrogenase
(alpha-KGDH) in substantia nigra. Thioctic acid exerts antioxidant
activity through a thiol-disulphide redox couple and is an essential
cofactor for alpha-KGDH. However, it is not known whether or not
thioctic acid enters basal ganglia or exerts beneficial effects in
Parkinson's disease. As a global measure of altered cerebral
function, the effect of R- and S-thioctic acid on 14C-2-deoxyglucose
(14C-2DG) incorporation was investigated in rats. Rats were treated
with either R- or S-thioctic acid (50 mg/kg IP) or 0.9% saline
acutely or for 5 days and 14C-2DG incorporation in basal ganglia was
assessed. Following acute administration, R- but not S-thioctic acid
caused an overall increase in 14C-2DG incorporation that was
significant in both substantia nigra zona compacta and zona
reticulata. R-thioctic acid also increased the incorporation of
14C-2DG in the medial forebrain bundle, thalamus, and red nucleus.
S-thioctic acid decreased 14C-2DG incorporation in the subthalamic
nucleus, but increased it in the red nucleus. Following repeated
administration, R-thioctic acid no longer increased 14C-2DG
incorporation in either zona compacta or zona reticulata of
substantia nigra. However, both R- and S-thioctic acid now decreased
14C-2DG incorporation in the subthalamic nucleus. The data suggest
that thioctic acid does enter the brain can alter neuronal activity
in areas of the basal ganglia intimately associated with the motor
deficits exhibited in Parkinson's disease.
