1. Department of Pharmacology and Toxicology; College of Pharmacy; University of Arizona; 1703 East Mabel Street P. O. Box 210207 Tuscon AZ 85721 USA
2. Departamento de Fisiologia e Farmacologia; Universidade Federal do Ceará; Fortaleza CE 60.430-270 Brazil
3. Instituto do Mar; Universidade Federal de São Paulo; Santos SP 11.070-100 Brazil
4. Waitt Advanced Biophotonics Center; The Salk Institute for Biological Sciences; 10010 North Torrey Pines Road La Jolla CA 92037 USA
5. Department of Chemistry; Purdue University; West Lafayette IN 47907 USA
6. Present address: On Target Laboratories; 1281 Win Hentschel Boulevard West Lafayette IN 47907 USA
7. Departamento de Farmacologia; Universidade de São Paulo; São Paulo SP 05508-900 Brazil
8. Xenobe Research Institute; P. O. Box 3052 San Diego CA 92163-1052 USA