1. Laboratory of Molecular Neurobiology, Department of Medical Biochemistry & Biophysics, Karolinska Institutet Scheeles vag 1 S‐171 77 Stockholm Sweden
2. Institute of Biophysics of Academy of Sciences of the Czech Republic & Institute of Experimental Biology, Faculty of Science, Masaryk University Kotlarska 2 611 37 Brno Czech Republic
3. Zoologisches Institut II, Universität Karlsruhe (TH) Kaiserstrasse 12 D‐76131 Karlsruhe Germany
4. Boston University, Boston 650 Albany Street Massachusetts 02118 USA
5. Section of Receptor Biology & Signaling, Department of Physiology & Pharmacology, Karolinska Institutet Nanna Svartz väg 2 S‐171 77 Stockholm Sweden