Participation of dopaminergic system in the dynamics of behavioral reactions of aging rats of both sexes under daily testing in the open field

Abstract

Under daily testing of aging rats of both sexes in the open field a slow lowering of motion activity is observed: by the 6th day of the experiment the passed distance of male rats reduces by 41% (р≤0.01), and of female rats – by 46% (р≤0.05) in comparison to the background values. The blockade of monoamine oxidase-B (МАО-В) by selegiline (intraperitoneal Introduction of 5 mg/kg one hour before testing) does not significantly change the orientation and intensity of this process, but probably contribute to the formation of a more comfortable psycho-emotional state of the animals. Consequently, the central dopamine cannot prevent from the motion activity lowering process of aging rats under daily testing, at least, in the frames of the experiment method used in this research. We obtained the evidence in favor of the fact that the suppression of the motion activity under daily testing is rather connected with the animals’ loss of motivation for research than with the growing anxiety.