Department of Integrative Biology and Pharmacology and the Institute of Molecular Medicine, University of Texas Medical School, 6431 Fannin, MSB 4.100, Houston, TX 77030; Department of Pharmacology A6, Graduate School of Medicine, Osaka University, 2-2 Yamadaoka, Suita, Osaka 565-0871, Japan; and Department of Pharmacology, Graduate School of Dentistry, Osaka University, 1-8 Yamadaoka, Suita, Osaka 565-0871, Japan (At 2003-04-28)