The activation of mice's behavior and reduction of brain beta-adrenergic receptor binding following repeated administration of antidepressant drugs.

In view of the fact that antidepressant drugs have almost no effect on a normal person's emotion and behavior, it seems necessary to examine their effects on animal behavior under abnormal, or stressful conditions. When mice were put into a water wheel apparatus, they tried to escape from the water by turning the wheel. This "wheel-turning behavior" was activated by repeated doses of imipramine or amitriptyline. The increase was paralleled by a reduction of brain beta-adrenergic receptor binding. It was speculated that chronic doses of antidepressants would increase escape behavior in mice when they were placed in a critical situation. The causal relationships between this behavioral change and beta-receptor function in brain remains to be further examined.