[Ribonuclease and DNA-dependent-RNA-polymerase activity in the brain under normal physiologic conditions].

Ribonuclease activity of nuclear, ribosomal and soluble fractions and DNA linked RNA polymerase activity of rat brain has been studied following alimentary, conditioned alimentary stimulation and conditioned alimentary inhibition. During alimentary and conditioned alimentary stimulation ribonuclease activity is considerably reduced at pH 5.4; 6.0; 7.9 and 8.1 but not at pH 7.6. Under these same conditions ribonuclease activity is high in soluble fraction. DNA-linked RNA-polymerase activity increases during stimulation. During conditioned alimentary inhibition ribonuclease activity of various subcellular fractions is also reduced. Ribonuclease activity of soluble fraction is lower than that observed during stimulation. During inhibition DNA-dependent RNA-polymerase activity is also significantly raised. The significant reduction of ribonuclease activity of nuclear and ribosomal fractions and the significant increase of DNA-dependent RNA-polymerase activity in the nuclear fraction during stimulation and inhibition of brain activity indicate the importance of RNA-polymerase and the biosynthesis of different kinds of RNA during activity of higher brain centers.