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Central integration and neural control of blood pressure during the cold pressor test: a comparison between

Sara S Jarvis1, Yoshiyuki Okada2, Benjamin D Levine2

  • 1Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Dallas, Texas University of Texas Southwestern Medical Center, Dallas, Texas Department of Biological Sciences, Northern Arizona University, Flagstaff, Arizona.

Physiological Reports
|October 15, 2015
PubMed

Insights

Six months of treatment with aliskiren or hydrochlorothiazide lowered blood pressure in older adults with hypertension. However, neither medication effectively reduced sympathetic nerve activity responses during a cold pressor test.

Area of Science:

  • Cardiovascular medicine
  • Pharmacology

Background:

  • Hypertension and sympathetic overactivity increase cardiovascular event risk.
  • Thiazide diuretics are established hypertension treatments, while renin inhibitors are newer options.

Purpose of the Study:

  • To compare the effects of aliskiren (ALSK) and hydrochlorothiazide (HCTZ) on blood pressure (BP) and muscle sympathetic nerve activity (MSNA) during a cold pressor test (CPT) in older adults with mild hypertension.
  • To test the hypothesis that aliskiren would blunt CPT responses more than hydrochlorothiazide.

Main Methods:

  • Nineteen older adults with mild hypertension underwent a CPT before and after 6 months of treatment with either ALSK or HCTZ.
  • Measurements included heart rate (HR), systolic BP (SBP), diastolic BP (DBP), and MSNA.
  • Blood samples were analyzed for renal-adrenal hormones.

Main Results:

  • Both ALSK and HCTZ effectively lowered ambulatory SBP and DBP.
  • Direct renin levels tended to increase with ALSK, while aldosterone increased with HCTZ.
  • Both groups exhibited expected increases in HR, BP, and MSNA during CPT.
  • No significant differences in cardiovascular or MSNA responses to CPT were observed post-treatment compared to pre-treatment in either group.

Conclusions:

  • Six-month treatment with either aliskiren or hydrochlorothiazide lowers BP in older adults with mild hypertension.
  • Neither medication demonstrated a significant effect in blunting sympathetic nervous system reactivity to cold stress as measured by CPT.
  • Further research is needed to explore the long-term impact of these antihypertensives on sympathetic activity.

Keywords:
Muscle sympathetic nerve activityrenin inhibitionthiazide diuretic

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