Inhibitory effect of papaverine on HVJ (Sendai virus) replication in rat glioma C6 cells.

The replication of HVJ (Sendai virus) in C6 rat glial cells was found to be inhibited by treatment of the cells with papaverine, an inhibitor of cAMP phosphodiesterase, but not with cAMP or dibutyryl cAMP. In addition, cyclic GMP which often manifests a reciprocal relationship to cAMP did not counteract the inhibition of HVJ yield by papaverine. Both viral genome replication and transcription were suppressed slightly by treatment of the cells with papaverine. In the cells cultured in the presence of papaverine, the synthesis of viral proteins and their phosphorylation occurred at normal rates. Membrane immunofluorescence and cell surface immunoprecipitation showed that the viral glycoproteins HN and F0 were expressed on the cell surface of the papaverine-treated cells. Moreover, all the viral structural proteins were associated with plasma membrane isolated from the treated cells. These results indicate that papaverine treatment suppresses some part of the process of virus budding at the plasma membrane.