The major funding and core support for the Drug Abuse Research Center (DARC) are provided by the present grant. The objectives of the DARC have remained: 1) to provide a formal structure to encourage and facilitate communication and cooperation between basic research scientists with a common interest in drug abuse; 2) to promote the development and/or expansion of certain key areas in drug abuse research; and 3) to provide an inter-disciplinary educational environment for students and faculty interested in various areas of drug abuse research. The guiding philosophy of the Center is that drug abuse is a complex problem which must be studied at levels ranging from a drug's sub-cellular actions through its social impact. It is impossible for any individual investigator to possess the expertise to study drugs at all these levels. On the other hand, data, methods and concepts developed at one level may provide important leads for others working in another area. The key function of the Center has been to provide a formal structure for research and for encouraging interactions between scientists who, because of their different academic and professional affiliations, might never meet despite a common interest in the problems of drug abuse. In the present application, the components consist of a core grant, projects on the self-administration psychoactive drugs by animals and humans, a project on pharmacological modification of the effects of cocaine in animals and 2 projects on drug-induced neurotoxicity. The research will significantly expand our knowledge of the maintenance and consequences of drug abuse.