1. Department of Biomedical Sciences and Department of Chemistry & Biochemistry, Florida State University, Tallahassee, Florida 32306, Program for Molecular Neuroscience and Department of Neurology and Department of Physical Medicine and Rehabilitation, Mayo Medical and Graduate Schools, Rochester, Minnesota 55905, and Department of Biophysics, Universidade Federal de Sao Paulo, Escola Paulista de Medicina, Rua Tres de Maio, 100, 04044-020 Sao Paulo, Brazil