1. Pain Research Center, Department of Anesthesiology, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts 02115, USA
2. Anesthesiology Pain Research Group, Anesthesiology Department, University Hospital Center and University of Lausanne, CH-1011 Lausanne, Switzerland
3. Department of Cell Biology and Morphology (DBCM), University of Lausanne, CH-1005 Lausanne, Switzerland