THE EFFECT OF CHLORPROMAZINE AND HALOPERIDOL ON DNA-TRANSCRIPTION

The ability of human cells to repair DNA damage can be indirectly asse ssed by measuring transcriptional activity relating to active genes, a process referred to as RNA synthesis. This study was carried out to i nvestigate the effects of chlorpromazine and haloperidol on the transc riptional activity of actively transcribed genes as an expression of D NA damage and repair. Three cultured human fibroblast lines were used: two were ''normal'' in previous RNA recovery testings and one was abn ormally sensitive to UV irradiation. In the ''normal'' line, recovery of RNA synthesis occurred within 1 hour of UV after exposure to three concentrations of chlorpromazine (125, 250 and 500 ng/ml) and haloperi dol (5, 10 and 20 ng/ml). Following treatment with the same concentrat ions of chlorpromazine and haloperidol, the UV-sensitive cell line sho wed markedly depressed recovery of RNA synthesis at 1 and 4 hours. Com plete recovery was not reached even after 24 hours. Our results sugges t that neuroleptics widely used in clinical practice adversely affect cell lines that are sensitive to DNA-damaging agents.