The long-term goal of this research project is to examine the functional importance of neurotransmitters (primarily dopamine and norepinephrine) in the central nervous system. The immediate objective is to utilize a cerebroventricular perfusing technique in cat brain to examine the dynamic properties of dopamine in the nigrostriatal pathway and to examine the actions of drugs on this system. The biochemical properties of other putative neurotransmitters (5-hydroxytryptamine, gamma-hydroxybutyrate) may also be examined using the same technique.