1. Department of Toxicology, University of Cagliary, I09126 Cagliary, Italy, Department of Pharmaceutical Sciences and Biotechnology Center, University of Ferrara, I-44100 Ferrara, Italy, Institute of Pharmacology, University of Ferrara, I-44100 Ferrara, Italy, and Peptide Neurochemistry, LCBRA, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina 27707