Translational regulation in rat brain hemispheres.

Present studies on the sensitivity of the transcription process in rat cerebral hemispheres showed that the relative abundance and translation of free and bound poly (A)+ mRNAs in a reticulocyte mRNA-dependent system were reduced following 1 h and 4 h of ethanol or pentobarbital administration with free being affected to a greater extent than the bound poly (A)+ mRNAs. In addition, the energy-dependent nucleocytoplasmic transport of in vivo [3H]labeled nuclear RNA to surrogate cytoplasm was modified in response to ethanol exposure. The translocation of the labeled nuclear RNA fraction occurred only to the microsomal/ribosomal fractions of the cytoplasm, was stimulated by cyclic cAMP and abolished when the cytoplasm was depleted of its protein factors following streptomycin treatment, thereby establishing the translocated RNA as messenger RNA. It is concluded that the neural cell, in response to ethanol exposure, modifies the efficiency of nuclear processing and transport of mRNA. This nuclear restriction probably occurs at multi-levels during the post-transcriptional modification of mRNAs.