[Relationship between dopamine and iron contents in the brain of parkinsonian rats].

Using fast cyclic voltammetry (FCV), atomic absorption/flame emission spectrophotometry and high performance liquid chromatography for electrochemical detection, we studied the change in iron content in the substantia nigra (SN) of 6-hydroxydopamine (6-OHDA) lesioned Parkinsonian (PD) rats and the toxic effect of intranigral injection of iron on DA neurons. The neuroprotective effect of desferrioxamine mesylate was also observed. The results are as follows. (1) The iron content in SN on the lesioned side of 6-OHDA-lesioned PD rats was about three times as high as that in nonstandard PD rats. (2) The iron content in caudate putamen (CPu) on the lesioned side of PD rats was not different from that on the unlesioned side. (3) DA release as well as the content of DA and its metabolites were significantly decreased on the lesioned side of PD rats. (4) In the rats pretreated with intracerebroventricular desferrioxamine mesylate before 6-OHDA injection, the release and content of DA on the lesioned side were not significantly different from those on the unlesioned side. (5) Intranigral injection of 40 micrograms FeCl3 resulted in a dramatic reduction of both DA release and content in CPu. The above results strongly suggest that 6-OHDA reduces the DA release from CPu, in which iron plays an important role. Elevation of iron content in SN is one of the mechanisms responsible for the reduction of DA content. Desferrioxamine mesylate may exert a protective action on dopaminergic neurons.