[Changes in the circadian rhythm of respiratory activity in "depressive" rats as affected by tricyclic antidepressants].

At chronic administration imipramine (10 and 25 mg/kg) and amitriptyline (10 mg/kg) shift the acrophase of the circadian rhythm of the rest-activity cycles in rats for a later time of the day. On the contrary, repeated injections of reserpine led to the rhythm acrophase shift for an earlier time and this effect is less pronounced against the background of the antidepressants. The effects of imipramine and amitriptyline are more distinct in the animals which exhibit signs of "depressiveness" in the open field and are more sensitive to the agents according to the forced swimming test.