1. Department of Genetic Medicine, Weill Cornell Medical College, New York, NY 10065.
2. Departments of Chemistry, Immunology and Microbial Science, The Scripps Research Institute, La Jolla, CA 92037.
3. Committee on the Neurobiology of Addictive Disorders, The Scripps Research Institute, La Jolla, CA 92037.
4. Department of Pediatrics, Weill Cornell Medical College, New York, NY 10065.