1. M. Beltramo, N. Stella, D. Piomelli, The Neurosciences Institute, 10640 J. J. Hopkins Drive, San Diego, CA 92121, USA.
2. A. Calignano, School of Pharmacy, University of Naples, Italy 80131.
3. S. Y. Lin and A. Makriyannis, School of Pharmacy, University of Connecticut, Storrs, CT 06269, USA.