Impact of NOS, COX, and ROS Inhibition on Cerebral Blood Flow Regulation
Hypoxia, Hypercapnia
About this trial
This is an interventional basic science trial for Hypoxia focused on measuring Cerebral blood flow, Cyclooxygenase, Nitric oxide synthase, Reactive Oxygen Species
Eligibility Criteria
Inclusion Criteria:
- Age: 18 ≤ years ≤ 45
- Free of disease and otherwise healthy as determined by health history questionnaire
- Not currently taking medication with the exception of birth control as determined by health history questionnaire
- Low to moderate physical activity will be permitted and assessed by a physical activity questionnaire (≤ 4 hours of physical activity/week)
- Body mass index (BMI) < 25 kg/m2
- Resting blood pressure <140/<90 mmHg (lowest of three measures)
- Resting heart rate <100 bpm
- Resting pulse oximetry oxygen saturation (SPO2) >95%
Fasting venous blood values (average of two measures)
- Glucose <100 mg/dL
- Creatinine < 1.5 mg/dL
- Total cholesterol <200 mg/dL
i. HDL cholesterol >40 mg/dL (men) ii. HDL cholesterol >50 mg/dL (women) iii. LDL cholesterol < 130 mg/dL d. Triglycerides <150 mg/dL
Subjects must be willing to report to the laboratory on all study days after completing
- Minimum 10-hour fast
- Minimum 18-hours abstention from exercise, alcohol, caffeine, and non-steroidal anti-inflammatory drugs (i.e. aspirin, ibuprofen, and naproxen)
Additionally, women will
- Have a regular menstrual cycle (self-report)
- Be studied (study visit 1 and study visit 2) on days 1-5 of menstrual cycle (self- report).
Exclusion Criteria:
- Coronary artery disease
- Stroke
- Heart attack
- Heart valve disease
- Congestive heart failure
- Previous heart surgery
- Lung disease
- Peripheral vascular disease
- Gastrointestinal (GI) bleeding
- Allergy or Intolerance to Aspirin or NSAIDS
- History of renal/kidney disease, insufficiency, or injury
- Smoke or use tobacco within the last year
- Subject has an abnormality or contraindication to study participation, which is not covered in the eligibility criteria.
Additionally, women will be excluded if they are
- Pregnant (as determined by a urine pregnancy test on screening and study days)
- Currently breastfeeding (self-report)
- Post-menopausal (self-report)
Sites / Locations
- University of Wisconsin, Madison
Arms of the Study
Arm 1
Arm 2
Experimental
Experimental
NOS, COX, and ROS Inhibition
COX, NOS, and ROS Inhibition
Subjects will receive L-NMMA, ketorolac, then ascorbic acid via intravenous catheter. L-NMMA will have a 3 mg kg-1 loading dose over 5-minutes (36 mg kg-1 hr-1), followed by a maintenance dose of 1 mg kg-1 hr-1. Ketorolac will have a 0.3 mg kg-1 loading dose over 5 minutes (3.6 mg kg-1 hr-1) with a minimum loading dose of 15 mg. This will be followed by a maintenance dose of 0.03 mg kg-1 hr-1. Ascorbic acid will have a loading dose of 0.035 g kg fat-free mass-1 over 5-minutes (0.42 g kg fat-free mass-1 hr-1), followed by a maintenance dose of 0.060 g kg fat-free mass-1 hr-1. Cerebral blood flow velocity will be measured throughout the drug infusions via transcranial Doppler ultrasound.
Subjects will receive ketorolac, L-NMMA, then ascorbic acid via intravenous catheter. Ketorolac will have a 0.3 mg kg-1 loading dose over 5 minutes (3.6 mg kg-1 hr-1) with a minimum loading dose of 15 mg. This will be followed by a maintenance dose of 0.03 mg kg-1 hr-1. L-NMMA will have a 3 mg kg-1 loading dose over 5-minutes (36 mg kg-1 hr-1), followed by a maintenance dose of 1 mg kg-1 hr-1. Ascorbic acid will have a loading dose of 0.035 g kg fat-free mass-1 over 5-minutes (0.42 g kg fat-free mass-1 hr-1), followed by a maintenance dose of 0.060 g kg fat-free mass-1 hr-1. Cerebral blood flow velocity will be measured throughout the drug infusions via transcranial Doppler ultrasound.