DEAFFERENTATION INDUCES EARLY AND DELAYED DIFFERENTIAL CHANGES IN THEPATTERN OF EXPRESSION OF THE VARIOUS GUANINE-NUCLEOTIDE-BINDING PROTEIN MESSENGER-RNAS IN RAT STRIATUM

A polymerase chain reaction-derived method was used to identify and qu antitate the relative abundance of the different mRNAs encoding variou s isoforms of the guanine nucleotide regulatory protein G(s), G(i), an d G(o) alpha subunits in the striata of rats unilaterally injected wit h 6-hydroxydopamine in the substantia nigra. Thirty days after the les ion, the mRNA levels of the Gd and of the G(i) 1 alpha subunits were i ncreased by about 2-3 times, those of the Gi 3 decreased by about 60% and those of G(i) 2 and G(s) unmodified. The pattern of expression of the G(o) alpha subunits mRNA changed in a time-dependent fashion, bein g significant 20 days after the lesion. The decrease in G(i) 3 alpha s ubunit 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 alpha su bunit mRNA showed a byphasic behaviour being reduced at 10 days and in creased at 30 days after the lesion. These data suggest that the expre ssion of the various G protein alpha subunits in the striatum are cont inuously regulated by factors originating from afferent neurons and su rrounding cells.