1. The Neurotransporter Group, Section of Anatomy, Department of Molecular Medicine; Institute of Basic Medical Sciences, University of Oslo; Oslo 0317 Norway
2. Department of Pharmaceutical Biotechnology and Molecular Biology; Center for Neurosciences, Vrije Universiteit Brussel; Brussels 1090 Belgium
3. Laboratory of Biochemistry and Molecular Biology, Department of Medical Technology; Niigata University; Niigata Niigata Prefecture 950-2181 Japan