The effect of antidepressants on behavioral despair in rats.

A possibility of inducing immobility in rats immersed in a cylinder filled with water from which they cannot escape was confirmed. The period of active attempts to escape from the cylinder was lengthened by injecting the animals with the following antidepressants: imipramine (IMI), amitriptyline (AMI), doxepin (DOS), mianserin (MIA), danitracen (DAN), iprindole (IPR), as well as cyproheptadine (CYP), even if they were administered only once. Femoxetine (FEM) produces no effect,. The swimming activity of rats diminished gradually to ca 15% of the initial value if experiments were repeated during 7-8 consecutive days. A chronic administration of IMI in a dose of 10mg/kg daily counteracted this phenomenon, and when the drug had been given for 10 days before the immersions were started, it presented the decrease in the activity.