1. Departments of Pharmaceutical Sciences and Pharmacology, Alma Mater Studiorum, University of Bologna, Via Belmeloro 6, 40126 Bologna, Italy, Research and Development Division, Recordati S.p.A., Via Civitali 1, 20148 Milano, Italy, and Department of Chemical Sciences, University of Camerino, Via S. Agostino 1, 62032 Camerino (MC), Italy