Mitotic recombination: a genotoxic effect of the antidepressant citalopram in Aspergillus nidulans

This report evaluates the potential of the antidepressant drug citalopram to induce homozygotization of genes previously present in a heterozygous condition, by homologous recombination. In order to address this question, a heterozygous diploid strain of the filamentous fungus Aspergillus nidulans and the homozygotization assay were utilized. Non-cytotoxic concentrations of citalopram (50, 75 and 100 μmol/L) showed a strong recombinogenic effect in A. nidulans, inducing homozygosis of the diploid strain's nutritional markers. The genetic markers exhibited homozygotization index (HI) rates higher than 2.0 and significantly different from HI control ones. Since citalopram has been previously characterized as a DNA synthesis inhibitor, the recombinogenic potential of this antidepressant in A. nidulans may be associated with the recombinational repair of citalopram-induced DNA strand breaks.