The Role of Aldosterone on Augmented Exercise Pressor Reflex in Hypertension
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ClinicalTrials.gov Identifier: NCT01996449 |
Recruitment Status :
Recruiting
First Posted : November 27, 2013
Last Update Posted : March 19, 2021
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Condition or disease | Intervention/treatment | Phase |
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Hypertension | Drug: Eplerenone Drug: Amlodipine Procedure: Microneurography Procedure: Rhythmic handgrip exercise Procedure: Sustained hand grip Procedure: Forearm blood flow Procedure: Arm cycling exercise Procedure: Cold Pressor test | Not Applicable |
Hypertensive patients are known to display exaggerated rise in blood pressure (BP) during exercise but the underlying mechanisms are poorly understood.
Traditionally, muscle afferents were dichotomized as metaboreceptors, which are activated slowly and only during intense or ischemic muscle contraction, or mechanoreceptors, which respond quickly to even mild deformation of their receptive fields. The increase in sympathetic nerve activity and BP caused by activation of these receptors, known as exercise pressor reflex, is normally buffered by activation arterial baroreceptors, which are reset to operate at higher BP range but at the same level of sensitivity. Mechanisms responsible for overactive exercise pressor reflex in hypertension remain unknown, but an increasing body of evidence suggested a role for aldosterone in regulating resting central sympathetic outflow in both hypertensive rats and humans.
Experiments will be performed on 3 groups of subjects 1) stage I (140-159/90-99 mmHg) subjects with essential hypertension, 2) stage I hypertensive subjects with Primary Aldosteronism (PA), and 3) normotensive controls. All participants will attend a baseline study visit, which will include a physical examination, a medical history review, vital sign measurements, and blood and urine collection. Small electrodes will be used to measure muscle nerve activity while the subjects perform a series of exercises that include passive arm cycling, active arm cycling, rhythmic hand grip, sustained hand grip and cold pressor test. Muscle blood flow will be measured before and after hand grip exercises.
A subgroup of subjects with essential hypertension and PA will be assigned to receive Eplerenone or Amlodipine on a randomized, double-blinded design. Participants will attend two weeks visits over a period of 16 weeks. Study visits include measurement of vital signs and blood samples collection. After completing 8 weeks on each medication, muscle nerve activity will be measured while performing the same exercises described in the baseline study visit.
Study Type : | Interventional (Clinical Trial) |
Estimated Enrollment : | 3 participants |
Allocation: | Randomized |
Intervention Model: | Crossover Assignment |
Masking: | None (Open Label) |
Primary Purpose: | Diagnostic |
Official Title: | The Role of Aldosterone on Augmented Exercise Pressor Reflex in Hypertension |
Study Start Date : | July 2013 |
Estimated Primary Completion Date : | December 2021 |
Estimated Study Completion Date : | December 2021 |

Arm | Intervention/treatment |
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Active Comparator: Initial treatment with Amlodipine
The subject will be started on Amlodipine 2.5-10 mg daily, which he or she will continue for a period of 12 weeks. Following the 12-week treatment period, the procedures listed below will be performed. After completion of the study procedures, the medication will be discontinued. The subject will be started on Eplerenone 50 - 200 mg daily, which he or she will continue for a period of 8 weeks. Following the 8 week treatment period, the procedures listed below will be performed. After completion of the study procedures, the medication will be discontinued.
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Drug: Eplerenone
The subject will be started on Eplerenone (Inspra) 50-200mg daily, which he or she will continue for a period of 8 weeks. Following the 8-week treatment period, the procedures listed below will be performed. After completion of the study procedures, the medication will be discontinued
Other Name: Inspra Drug: Amlodipine The subject will be started on Amlodipine (Norvasc) 2.5 -10mg daily, which he or she will continue for a period of 8 weeks. Following the 8-week treatment period, the procedures listed below will be performed. After completion of the study procedures, the medication will be discontinued.
Other Name: Norvasc Procedure: Microneurography Investigators will measure sympathetic nerve activity from the peroneal nerve by inserting a tiny needle directly into the nerve in the leg. Investigators will localize the nerve by electrical stimulation over the skin using a blunt probe. With this stimulation, subject will notice either involuntary twitching or a tingling sensation, which may be annoying but not painful. Investigators will then introduce a tiny, sterile wire needle (an electrode) through the skin at the same location. When the tip of the needle enters the nerve, subjects may again notice involuntary muscle twitches or tingling in the leg. Investigators will then turn the electrical stimulator off and make minor adjustments in the position of the needle until investigators begin to record the nerve signals. The recording needle will remain in position throughout the study.
Other Name: Assessment of sympathetic nerve activity (SNA) Procedure: Rhythmic handgrip exercise Subjects will perform a rhythmic handgrip exercise at 30% or 45% of maximal voluntary contraction for 3 minutes. Investigators will measure cardiac output (non-invasive impedance plethysmography), blood pressure, and sympathetic nerve activity (SNA) at baseline and following this handgrip exercise Procedure: Sustained hand grip Subjects will perform a sustained handgrip exercise at 30% of maximal voluntary contraction for 3 minutes. Investigators will measure cardiac output (non-invasive impedance plethysmography), blood pressure, and sympathetic nerve activity (SNA) at baseline and following this handgrip exercise. Procedure: Forearm blood flow Using high-resolution ultrasound, investigators will measure skeletal muscle blood flow in the forearm at rest, following sustained handgrip exercise Procedure: Arm cycling exercise Subjects will perform a cycling arm exercise with a stationary cycling device. Investigators will measure cardiac output (non-invasive impedance plethysmography), blood pressure, and sympathetic nerve activity (SNA) at baseline and following this exercise. Procedure: Cold Pressor test Subjects will place hand in cold water with ice for 3 minutes. Investigators will measure cardiac output (non-invasive impedance plethysmography), blood pressure, and sympathetic nerve activity (SNA) at baseline, during and 2 minutes after the test. |
Active Comparator: Initial treatment with Eplerenone
The subject will be started on Eplerenone 50 - 200 mg daily, which he or she will continue for a period of 12 weeks. Following the 12-week treatment period, the procedures listed below will be performed. After completion of the study procedures, the medication will be discontinued. The subject will be started on Amlodipine 2.5-10 mg daily, which he or she will continue for a period of 8 weeks. Following the 8 week treatment period, the procedures listed below will be performed. After completion of the study procedures, the medication will be discontinued.
|
Drug: Eplerenone
The subject will be started on Eplerenone (Inspra) 50-200mg daily, which he or she will continue for a period of 8 weeks. Following the 8-week treatment period, the procedures listed below will be performed. After completion of the study procedures, the medication will be discontinued
Other Name: Inspra Drug: Amlodipine The subject will be started on Amlodipine (Norvasc) 2.5 -10mg daily, which he or she will continue for a period of 8 weeks. Following the 8-week treatment period, the procedures listed below will be performed. After completion of the study procedures, the medication will be discontinued.
Other Name: Norvasc Procedure: Microneurography Investigators will measure sympathetic nerve activity from the peroneal nerve by inserting a tiny needle directly into the nerve in the leg. Investigators will localize the nerve by electrical stimulation over the skin using a blunt probe. With this stimulation, subject will notice either involuntary twitching or a tingling sensation, which may be annoying but not painful. Investigators will then introduce a tiny, sterile wire needle (an electrode) through the skin at the same location. When the tip of the needle enters the nerve, subjects may again notice involuntary muscle twitches or tingling in the leg. Investigators will then turn the electrical stimulator off and make minor adjustments in the position of the needle until investigators begin to record the nerve signals. The recording needle will remain in position throughout the study.
Other Name: Assessment of sympathetic nerve activity (SNA) Procedure: Rhythmic handgrip exercise Subjects will perform a rhythmic handgrip exercise at 30% or 45% of maximal voluntary contraction for 3 minutes. Investigators will measure cardiac output (non-invasive impedance plethysmography), blood pressure, and sympathetic nerve activity (SNA) at baseline and following this handgrip exercise Procedure: Sustained hand grip Subjects will perform a sustained handgrip exercise at 30% of maximal voluntary contraction for 3 minutes. Investigators will measure cardiac output (non-invasive impedance plethysmography), blood pressure, and sympathetic nerve activity (SNA) at baseline and following this handgrip exercise. Procedure: Forearm blood flow Using high-resolution ultrasound, investigators will measure skeletal muscle blood flow in the forearm at rest, following sustained handgrip exercise Procedure: Arm cycling exercise Subjects will perform a cycling arm exercise with a stationary cycling device. Investigators will measure cardiac output (non-invasive impedance plethysmography), blood pressure, and sympathetic nerve activity (SNA) at baseline and following this exercise. Procedure: Cold Pressor test Subjects will place hand in cold water with ice for 3 minutes. Investigators will measure cardiac output (non-invasive impedance plethysmography), blood pressure, and sympathetic nerve activity (SNA) at baseline, during and 2 minutes after the test. |
- Muscle sympathetic nerve activity during exercise [ Time Frame: 8 weeks after initiation of spironolactone; ]
- Muscle sympathetic nerve activity during exercise [ Time Frame: 8 weeks after initiating Amlodipine ]

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Ages Eligible for Study: | 18 Years and older (Adult, Older Adult) |
Sexes Eligible for Study: | All |
Accepts Healthy Volunteers: | Yes |
Inclusion Criteria:
- Experiments will be performed on 3 groups of nondiabetic human subjects:
- 1) stage I (140-159/90-99 mmHg) subjects with essential hypertension.
- 2) stage I hypertensive subjects with primary aldosteronism
- 3) normotensive controls.
Exclusion Criteria:
- 1) Any evidence of cardiopulmonary disease, left ventricular hypertrophy or systolic dysfunction by echocardiography.
- 2) Blood pressure averaging ≥160/100 mmHg
- 3) Estimated glomerular filtration rate (eGFR) < 90 mL/min/1.73m2
- 4) Diabetes mellitus or other systemic illness
- 5) Pregnancy
- 6) Hypersensitivity to nitroprusside, phenylephrine, amlodipine or eplerenone
- 7) Any history of substance abuse or current cigarette use
- 8) Any history of psychiatric illness
- 9) History of malignancy

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.
Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT01996449
Contact: Debbie Arbique, DNP | (214)648-3188 | debbie.arbique@utsouthwestern.edu | |
Contact: Poghni Peri-Okonny, MD | 2146483180 | poghni.peri-okonny@utsouthwestern.edu |
United States, Texas | |
UT Southwestern Medical Center | Recruiting |
Dallas, Texas, United States, 75390 | |
Contact: Debbie Arbique, DNP 214-648-3188 debbie.arbique@utsouthwestern.edu |
Principal Investigator: | Wanpen Vongpatanasin, MD | UT Southwestern Medical Center |
Responsible Party: | Wanpen Vongpatanasin, Professor, University of Texas Southwestern Medical Center |
ClinicalTrials.gov Identifier: | NCT01996449 |
Other Study ID Numbers: |
R01HL113738 ( U.S. NIH Grant/Contract ) |
First Posted: | November 27, 2013 Key Record Dates |
Last Update Posted: | March 19, 2021 |
Last Verified: | March 2021 |
Hypertension blood pressure Aldosterone Eplerenone Amlodipine |
Primary aldosteronism Exercise pressor reflex handgrip exercise passive arm cycling active arm cycling |
Hypertension Vascular Diseases Cardiovascular Diseases Amlodipine Eplerenone Antihypertensive Agents Calcium Channel Blockers Membrane Transport Modulators Molecular Mechanisms of Pharmacological Action |
Calcium-Regulating Hormones and Agents Physiological Effects of Drugs Vasodilator Agents Mineralocorticoid Receptor Antagonists Hormone Antagonists Hormones, Hormone Substitutes, and Hormone Antagonists Diuretics, Potassium Sparing Diuretics Natriuretic Agents |