1. H. Tiedge [] is in the Department of Physiology and Pharmacology, State University of New York Health Science Center at Brooklyn, Brooklyn, NY 11203, USA.
2. F. E. Bloom [] is in the Department of Neuropharmacology, Scripps Research Institute, La Jolla, CA 92037, USA.
3. D. Richter [] is in the Institut für Zellbiochemie und Klinische Neurobiologie, Universität Hamburg, Hamburg, Germany.