1. Alkermes, Inc., Cambridge
2. Department of Pharmacology and Experimental Therapeutics, Cortex Pharmaceuticals, Irvine, California, U.S.A.
3. Department of Pharmacology and Experimental Therapeutics, Tufts University Medical Center, Boston, Massachusetts
4. Department of Pharmacology and Experimental Therapeutics, University of California at Irvine, Irvine, California, U.S.A.