1. Department of Medical Pharmacology and Physiology, and Dalton Cardiovascular Research Center, University of Missouri-Columbia, Missouri 65211
2. Department of Hygiene and Public Health and Department of Physiology, Osaka Medical College, Takatsuki, Osaka 569-8686, Japan
3. Department of Pharmacology and Neuroscience, Keio University School of Medicine, Shinjuku, Tokyo 160-8582, Japan