Increased dietary salt intake enhances the exercise pressor reflex

Katsuya Yamauchi, Hirotsugu Tsuchimochi, Audrey J. Stone, Sean Stocker, Marc Kaufman

Research output: Contribution to journalArticle

11 Citations (Scopus)

Abstract

Increased dietary salt in rats has been shown to sensitize central sympathetic circuits and enhance sympathetic responses to several stressors, including hyperinsulinemia, intracerebroventricular injection of angiotensin, and electrical stimulation of sciatic nerve afferents. These findings prompted us to test the hypothesis that increased dietary salt enhanced the exercise pressor reflex. Male Sprague-Dawley rats were fed 0.1% (low) or 4.0% (high) NaCl chow for 2 to 3 wk. On the day of the experiment, the rats were decerebrated, and the hind limb muscles were statically contracted for 30 s by electrically stimulating the cut peripheral ends of the L4 and L5 ventral roots. We found that contraction produced a significantly greater increase in mean arterial pressure of rats fed 4.0% (n = 26) vs. 0.1% (n = 22) NaCl (24 ± 2 vs. 15 ± 2 mmHg, respectively; P < 0.05). Baseline mean arterial pressure was not different between groups (0.1%, 77 ± 4 vs. 4.0% NaCl, 80 ± 3 mmHg). Likewise, the tension time indexes were not different between the two groups (P = 0.42). Section of the L4 and L5 dorsal roots greatly attenuated both the pressor and cardioaccelerator responses to contraction in both groups of rats, an effect showing that the responses were reflex in origin. Finally, electrical stimulation of the lumbar sympathetic chain produced similar increases in mean arterial pressure and decreases in femoral arterial blood flow and conductance between rats fed 0.1% vs. 4.0% NaCl diets. We conclude that increased dietary salt enhances the exercise pressor reflex.

Original languageEnglish (US)
JournalAmerican Journal of Physiology - Heart and Circulatory Physiology
Volume306
Issue number3
DOIs
StatePublished - Feb 1 2014

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Reflex
Salts
Arterial Pressure
Spinal Nerve Roots
Electric Stimulation
Angiotensins
Hyperinsulinism
Sciatic Nerve
Thigh
Sprague Dawley Rats
Extremities
Diet
Muscles
Injections

All Science Journal Classification (ASJC) codes

  • Physiology
  • Cardiology and Cardiovascular Medicine
  • Physiology (medical)

Cite this

Yamauchi, Katsuya ; Tsuchimochi, Hirotsugu ; Stone, Audrey J. ; Stocker, Sean ; Kaufman, Marc. / Increased dietary salt intake enhances the exercise pressor reflex. In: American Journal of Physiology - Heart and Circulatory Physiology. 2014 ; Vol. 306, No. 3.
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Increased dietary salt intake enhances the exercise pressor reflex. / Yamauchi, Katsuya; Tsuchimochi, Hirotsugu; Stone, Audrey J.; Stocker, Sean; Kaufman, Marc.

In: American Journal of Physiology - Heart and Circulatory Physiology, Vol. 306, No. 3, 01.02.2014.

Research output: Contribution to journalArticle

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