INDIVIDUAL MOTOR-ACTIVITY - RELATIONSHIPS TO DOPAMINERGIC RESPONSES

Owing to motor activity mice were divided into two groups in a running -wheel test: low-active mice (LAM) and high-active mice (HAM). Locomot or activities in the running wheel and in glass boxes are compared. Th e HAM showed a more intensive explorative behavior than LAM and were a lso more responsive in terms of exogenous factors than LAM. In contras t, LAM showed higher locomotor activity than HAM after habituation. An alyzing the response of LAM and HAM to dopaminergic agonists such as a pomorphine, bromocriptine, and amphetamine, the role of specific dopam inergic mechanisms for the two types is discussed. Although apomorphin e mainly stimulated the climbing activity in HAM, bromocriptine (climb ing activity) and amphetamine (locomotion) had stronger effects in LAM . Differences may be assumed between LAM and HAM concerning the nigros triatal and/or mesolimbic dopaminergic mechanisms. On the one hand, cl imbing activity following apomorphine application accompanied by stere otypes may suggest a stronger activation of striatal dopaminergic mech anisms in HAM. On the other hand, climbing activity following bromocri ptine accompanied by jumping behavior, as well as the stimulation of l ocomotion after amphetamine, suggests a more effective activation of m esolimbic dopaminergic structures in LAM.