[1] Rhein Westfal TH Aachen, Dept Pharmacol, D-52074 Aachen, Germany
[2] Rhein Westfal TH Aachen, Dept Biochem, D-52074 Aachen, Germany
[3] Rhein Westfal TH Aachen, Dept Anat, D-52074 Aachen, Germany
[4] Stanford Univ, Dept Mol Pharmacol, Stanford, CA 94305 USA