1. Department of Pharmacology (E.-Y.C., D.-I.C., K.-M.K), College of Pharmacy, Chonnam National University, Kwang-Ju 500-757, Korea;
2. Department of Biochemistry and Cellular and Molecular Biology (J.H.P), University of Tennessee, Knoxville, Tennessee 37996;
3. Department of Pharmacology and Toxicology (H.K.), Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka 812-8582, Japan;
4. Department of Cell Biology (M.G.C.), Duke University Medical Center, Durham, North Carolina 27710