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BACKGROUND AND AIMS: We investigated the number of proliferating cells in the dentate gyrus of the hippocampus and anxietylike behavior of mice after damage to the projections from the locus coeruleus as a result of a single administration (50 mg/kg) of DSP-4 that is a selective neurotoxin of central and peripheral noradrenergic neurons. METHODS: Adult male Swiss mice were divided into 2 groups whose behavior was examined for 3 and 15 days. Brain sections were examined immunohistochemically (IMH) 4 and 16 after the injection of DSP-4. I group was tested in open field (OF) and elevated plus maze (EPM) 3 days after injection of DSP-4 (n=4) or saline (n=8). 4 days after the injection the brains were dissected and investigated by immunohistochemistry. In II group the same behavioral and IMH procedures were performed 15 and 16 days after injection of DSP-4 (n=4) or saline (n=8). Cell proliferation was determined using 5-bromo-2’-deoxyuridine. RESULTS: In I group there were no significant changes in mice behavior in OF and EPM. In II group a significant effect of administration of DSP-4 on behavior of mice was observed only in the OF, no differences were observed in the EPM. The immunohistochemical studies in group I revealed significant decrease in number of proliferating cells in all examined section as compared to the control group. In group II an increased number of proliferating cells was found in all experimental groups. CONCLUSIONS: The results suggest that the reduced level of noradrenaline in brain that could have been produced by administration of DSP-4 may increase anxiety-like behavior in mice. The lesions of noradrenergic neurons caused by DSP-4 inhibit cell proliferation in the dentate gyrus but do not damage the progenitor cells which produce granule neurons in the hippocampus.