PROTEIN-SYNTHESIS INHIBITION INDUCES PERICHROMATIN GRANULE ACCUMULATION AND INTRANUCLEAR RODLET FORMATION IN OSMOTICALLY STIMULATED SUPRAOPTIC NEURONS

The distribution of perichromatin granules (PGs), a storage form of pr e-mRNAs, was studied in supraoptic neurons of control and osmotically stimulated rats, and also after treatment with cycloheximide, a protei n-synthesis inhibitor. In non-cycloheximide-treated rats, neuronal act ivation by dehydration significantly decreased the number of PGs. Conv ersely, PGs were drastically increased in the supraoptic neurons of de hydrated rats treated with cycloheximide for 4 h. This suggests that c ycloheximide does not interfere with the transcriptional activation in duced by dehydration, but it affects the processing of newly synthesiz ed pre-mRNAs. Moreover, protein-synthesis inhibition was associated wi th the formation of intranuclear bundles of tubular filaments.