Deafferentation induces early and delayed differential changes in the pattern of expression of the various guanine nucleotide binding protein mRNAs in rat striatum

A polymerase chain reaction-derived method was used to identify and quantitate the relative abundance of the different mRNAs encoding various isoforms of the guanine nucleotide regulatory protein G_s, G_i, and G_o α subunits in the striata of rats unilaterally injected with 6-hydroxydopamine in the substantia nigra. Thirty days after the lesion, the mRNA levels of the G_o and of the G_i 1 α subunits were increased by about 2-3 times, those of the G_i 3 decreased by about 60% and those of G_i 2 and G_s unmodified. The pattern of expression of the G_o α subunits mRNA changed in a time-dependent fashion, being significant 20 days after the lesion. The decrease in G_i 3 α subunit mRNA levels was maximum 10 days after the lesion and tended to be reduced in magnitude with time while the changes in G_i 1 α subunit mRNA showed a byphasic behaviour being reduced at 10 days and increased at 30 days after the lesion. These data suggest that the expression of the various G protein α subunits in the striatum are continuously regulated by factors originating from afferent neurons and surrounding cells.