Key Criteria:  Normotensive male or female volunteers between 25-65 years old Deemed healthy on the basis of a clinical history, physical examination, ECG, vital signs, and laboratory tests of blood and urine  Key Exclusion Criteria:  Clinically relevant abnormal findings at the screening assessments Clinically relevant abnormal medical history or concurrent medical condition Acute or chronic illness Contraindications to MRI, CT, PET, or arterial cannulation procedures Significant exposure to research related radiation or other exposure (defined as ICRP category IIb or no more than 10 mSv) Positive tests for hepatitis B surface antigen (HBsAg) & Hepatitis C virus (HCV) antibody, human immunodeficiency virus (HIV) antibody Drug or alcohol abuse Smoke more than 10 cigarettes daily Loss of more than 400 mL blood Vital signs or ECGs outside the acceptable range