1. Department of Anesthesiology; College of Physicians and Surgeons; Columbia University Medical Center; Columbia University; P&S Box 46, 630 West 168th Street New York NY 10032 USA
2. Department of Physiology and Biophysics; Faculty of Medicine and Health Sciences; Université de Sherbrooke; 3001, 12th Avenue North Sherbrooke QC J1H 5N4 Canada
3. Institut de pharmacologie de Sherbrooke and Centre de recherche du CHUS; Université de Sherbrooke; Sherbrooke QC Canada