Purpose:To compare the effects of the antidepressant drugs duloxetine and fluoxetine on depressive behaviors in rodents. Methods: Eighteen male Wistar rats were given systemic injections of duloxetine, fluoxetine, or saline prior to a Forced Swimming Test (FST). Immobility and number of stops were measured. Results: Rats given injections of fluoxetine displayed significantly less immobility (p = 0.02) and fewer stops than the control group (p = 0.003). Duloxetine significanlty reduced the number of stops (p = 0.003), but did not effect immobility (p = 0.48). Conclusion: Duloxetine and fluoxetine reduced depressive behaviors in the Forced FST. However, our findings suggest that fluoxetine is more effective than duloxetine. Key words: Physiological Effects of Drugs. Fluoxetine. Depression. Animal Experimentation. RESUMO Objetivo:Comparar o efeito antidepressivo da droga cloridrato de duloxetina com a fluoxetina. Métodos: O teste do nado forçado, teste comportamental que avalia a atividade antidepressiva em ratos, foi utilizado em 18 ratos Wistar, machos adultos, divididos em três grupos iguais: duloxetina, fluoxetina e controle. Resultados: Os dados do teste do nado forçado foram analisados pelo teste One-way ANOVA, Mann Whitney e Kruskall-Wallis.Houve diferença significativa (p = 0,003) entre o número de paradas dos grupos duloxetina e fluoxetina e o grupo controle. Conclusão: A duloxetina e a fluoxetina tiveram frequência de paradas similares. A fluoxetina mostrou ser mais efetiva que a duloxetina no teste do nado forçado em ratos. Descritores: Efeitos Fisiológicos de Drogas. Fluoxetina. Depressão. Experimentação Animal. Ciulla L et al 352

Purpose:To compare the effects of the antidepressant drugs duloxetine and amitriptyline on depressive behaviors in rats. Methods: Fifteen male Wistar rats were given systemic injections of duloxetine, amitriptyline or saline prior to a Forced Swimming Test (FST). Immobility and number of stops were measured. Data were analyzed by one-way ANOVA and Kruskall-Wallis. Results: Rats given injections of duloxetine displayed fewer stops than the amitriptyline and control group (p< 0.05). The control group and Amitriptyline showed no difference (p=0.8