A neuronal nucleolar trigger mechanism traceable by a routine staining method.

In experimental Wilson's disease produced by the intracardiac injection of copper sulphate, it is seen that the glia-neuronal interactions play an important role in the pathogenesis of neural lesions. A "trigger" copper-RNA particle is transferred from the oligodendroglial nucleus to activate the neuronal nucleolus causing a flooding of the neurone with RNA. This trigger particle stains differently with Mason's trichrome, giving a bright red colour. This altered reaction gives an insight into the feedback process for the formation of ribosomal RNA in the neurones. The alteration appears to lead to a block in the repressor activity of the neuronal RNA formation.