1. Brain Research Laboratory and Department of Psychiatry, New York University Medical Center, New York, NY 10016, and Nathan S. Kline Psychiatric Research Institute, Orangeburg, NY 10962.
2. Department of Nuclear Medicine, Brookhaven National Laboratory, Upton, NY 11973.
3. Department of Physiology, University of West Indies, Kingston, Jamaica.
4. Department of Physiology, Nagasaki University School of Medicine, Nagasaki 852, Japan.