The major purpose of the research proposed is to study interrelationships between psychotropic drugs, transmitter biochemistry and behavior. The research will attempt to clarify the processes that mediate drug effects by studying drug effects on locomotion, operant behavior, feeding and drinking and will look at the biochemical processes that mediate these changes. A major thrust of the research will be to study how environmental and behavioral variables affect brain transmitter biochemistry and to determine how the alterations in brain transmitters can explain drug-behavior interactions. The effects of psychomotor stimulants or antidepressant drugs will be investigated with detailed descriptions of their effects on operant behavior. The neurochemical effects of tricyclic antidepressants and psychomotor stimulants will be examined to determine the modifications of central nervous system function which can account for the alterations in behavior. The effects of the behavioral situation on tramsmitter biochemistry will be investigated in order to infer how the drugs and behavioral/environmental variables mutually interact to account for the effects of the drugs on behavior. Tolerance to psychomotor stimulants will also be studied in relationship to behavior and brain transmitters. Psychomotor stimulants induce neural damage and the mechanism by which this occurs will be studied. In addition, pharmacologically and structurally related anorectic drugs will be studied to determine if they produce neural damage. The ontogenetic development of the catecholaminergic system and its involvement in the development of behaviors occurring at a latter time in life will be studied to further determine if there are critical times in the development of rats during which alterations of the transmitter system can produce changes in the behavior of the adult or neonatal rat. All of the projects in this proposal focus on the major purpose of the research which is to discover causal relationships between modifications of CNS transmitters, brain function and behavior.