Dose Response of Epinephrine

Inclusion Criteria: * healthy controls age 18-55 yr. * Body mass index \>21 kg · m-2 Exclusion Criteria: * Pregnant or breastfeeding women * Subjects unwilling or unable to comply with approved contraception measures * Subjects unable to give voluntary informed consent * Subjects on anticoagulant drugs, anemic or with known bleeding diatheses * Subjects with a history of severe, uncontrolled hypertension, heart disease, cerebrovascular incidents * Current tobacco use * Subjects with any known allergies to any of the study medications being used Physical Exam Exclusion Criteria * Uncontrolled severe hypertension (i.e., blood pressure greater than 160/100) * Clinically significant cardiac abnormalities (e.g. heart failure, arrhythmia) * Pneumonia treatment or hospitalization within 2 weeks prior to enrollment (study visit) * Hepatic failure / jaundice * Renal failure * Cerebrovascular accident occurrence or hospitalization within 4 weeks prior to enrollment * Fever greater than 38.0 degrees C Screening Laboratory Tests Exclusion Criteria * Hematocrit lower than 32 % * White blood cell (WBC) count lower than 3 thou/ul or greater than 14 thou/ul * Liver function tests: serum glutamic oxaloacetic transaminase (SGOT) and serum glutamic-pyruvic transaminase (SGPT) greater than twice upper limit of normal range * Alkaline phosphatase greater than 150U/L * Total bilirubin (TBil) greater than 2 mg/dl * Estimated glomerular filtration rate (eGFR) less than 60 mL/min/1.73 m2 * Positive human immunodeficiency virus (HIV), Hepatitis B or Hepatitis C * Any abnormal cardiac response during multi-stage exercise test (if over 40 years of age)