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. (C) 2010 Elsevier Ireland Ltd. All rights reserved.