RNA-polymerase, type I: activity in rat brain cell nuclei and peripheral blood mononuclear cells after Venezuelan equine encephalomyelitis virus infection.

Rats inoculated intraperitoneally with 100 LD50 of Venezuelan Equine Encephalomyelitis virus (VEE), showed a significant decrease of DNA-dependent RNA polymerase type I activity of brain nuclei of 29.7% and 59.3% at 24 and 48 hours after infection, respectively, while the animals had no clinical symptoms of illness. No alterations were observed in the nuclei of mononuclear cells at any time. VEE virus titer was higher in the serum than in the brain. The results suggest that viral infection produced a modification in the activity of this enzyme only in brain, even with a low amount of virus, and had no effect on enzyme activity of mononuclear cells.