Decreased RGS9 protein level in the striatum of rodents undergoing MPTP or 6-OHDA neurotoxicity.

Western blot has been used to study the time-course effect of the two most popular parkinsonian neurotoxins, 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP, i.p.) and 6-hydroxydopamine (6-OHDA, intra-substantia nigra), on the expression of several regulators of G-protein signaling (RGS2, 4 and 9) in striatum in rodents. During the few days after MPTP challenge, there was a decline (as expected) in tyrosine hydroxylase expression in the mouse striatum that was accompanied by a decline in RGS9 protein; the latter was specific and did not extend to RGS2 or RGS4 which were resistant to the MPTP challenge. Much the same pattern was observed in rats after 6-OHDA challenge, again, specific to RGS9, although the effect takes a few weeks, rather than a few days, to develop. These results may be helpful for the understanding of molecular mechanism underlying Parkinson's disease (PD) and RGS9 might involve in the striatal function associated with PD.