 |
 |
=46rom: http://www.thorne.com/altmedrev/recent1-3.html The isomers of thioctic acid alter C-deoxyglucose incorporation in ra= t basal ganglia.=20 Seaton TA, Jenner P, Marsden CD. Biochem Pharmacol 1996;51:983-986.= =20 Nigral cell death in Parkinson's disease is associated with decreased reduced glutathione (GSH) levels, impaired complex I activity and inh= ibition 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 no= t known whether or not thioctic acid enters basal ganglia or exerts beneficia= l effects in Parkinson's disease. As a global measure of altered cerebr= al function, the effect of R- and S-thioctic acid on 14C-2-deoxyglucose (14C-2DG) incorporation was investigated in rats. Rats were treated w= ith 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. Followi= ng acute administration, R- but not S-thioctic acid caused an overall in= crease in 14C-2DG incorporation that was significant in both substantia nigr= a zona compacta and zona reticulata. R-thioctic acid also increased the incorporation of 14C-2DG in the medial forebrain bundle, thalamus, an= d red nucleus. S-thioctic acid decreased 14C-2DG incorporation in the subth= alamic nucleus, but increased it in the red nucleus. Following repeated administration, R-thioctic acid no longer increased 14C-2DG incorpora= tion 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 t= he brain and can alter neuronal activity in areas of the basal ganglia intimately associated with the motor deficits exhibited in Parkinson= =D5s disease.=20