Abstract

An increasing number of studies have linked high dietary phosphate (Pi) intake to hypertension. It is well established that the rise in sympathetic nerve activity (SNA) and blood pressure (BP) during physical exertion is exaggerated in many forms of hypertension, which are primarily mediated by an overactive skeletal muscle exercise pressor reflex (EPR). However, it remains unknown whether high dietary Pi intake potentiates the EPR-mediated SNA and BP response to exercise. Accordingly, we measured renal SNA (RSNA) and mean BP (MBP) in normotensive Sprague-Dawley rats fed a normal Pi diet (0.6%, n = 13) or high Pi diet (1.2%, n = 13) for 3 mo. As previously reported, we found that resting BP was significantly increased by 1.2% Pi diet in both conscious and anesthetized animals. Activation of the EPR by electrically induced hindlimb contraction triggered greater increases in ΔRSNA and ΔMBP in the 1.2% compared with 0.6% Pi group (126 ± 25 vs. 42 ± 9%; 44 ± 5 vs. 14 ± 2 mmHg, respectively, P < 0.01). Activation of the muscle mechanoreflex, a component of the EPR, by passively stretching hindlimb muscle also evoked greater increases in ΔRSNA and ΔMBP in the 1.2% compared with 0.6% Pi group (109 ± 27 vs. 24 ± 7%, 38 ± 7 vs. 8 ± 2 mmHg, respectively, P < 0.01). A similar response was produced by hindlimb intra-arterial capsaicin administration to stimulate the metaboreflex arm of the EPR. Thus, our data demonstrate a novel action of dietary Pi loading in augmenting EPR function through overactivation of both the muscle mechanoreflex and metaboreflex.

Original languageEnglish (US)
Pages (from-to)R39-R48
JournalAmerican Journal of Physiology - Regulatory Integrative and Comparative Physiology
Volume311
Issue number1
DOIs
StatePublished - Jul 1 2016

Fingerprint

Reflex
Phosphates
Hypertension
Hindlimb
Blood Pressure
Diet
Kidney
Muscles
Physical Exertion
Capsaicin
Sprague Dawley Rats
Skeletal Muscle

Keywords

  • Blood pressure
  • Diet
  • Exercise pressor reflex
  • Hypertension
  • Phosphate
  • Sympathetic nerve activity
  • Western diet

ASJC Scopus subject areas

  • Physiology
  • Medicine(all)
  • Physiology (medical)

Cite this

@article{6869d46ddfa84c78a65668252d43a153,
title = "High dietary phosphate intake induces hypertension and augments exercise pressor reflex function in rats",
abstract = "An increasing number of studies have linked high dietary phosphate (Pi) intake to hypertension. It is well established that the rise in sympathetic nerve activity (SNA) and blood pressure (BP) during physical exertion is exaggerated in many forms of hypertension, which are primarily mediated by an overactive skeletal muscle exercise pressor reflex (EPR). However, it remains unknown whether high dietary Pi intake potentiates the EPR-mediated SNA and BP response to exercise. Accordingly, we measured renal SNA (RSNA) and mean BP (MBP) in normotensive Sprague-Dawley rats fed a normal Pi diet (0.6{\%}, n = 13) or high Pi diet (1.2{\%}, n = 13) for 3 mo. As previously reported, we found that resting BP was significantly increased by 1.2{\%} Pi diet in both conscious and anesthetized animals. Activation of the EPR by electrically induced hindlimb contraction triggered greater increases in ΔRSNA and ΔMBP in the 1.2{\%} compared with 0.6{\%} Pi group (126 ± 25 vs. 42 ± 9{\%}; 44 ± 5 vs. 14 ± 2 mmHg, respectively, P < 0.01). Activation of the muscle mechanoreflex, a component of the EPR, by passively stretching hindlimb muscle also evoked greater increases in ΔRSNA and ΔMBP in the 1.2{\%} compared with 0.6{\%} Pi group (109 ± 27 vs. 24 ± 7{\%}, 38 ± 7 vs. 8 ± 2 mmHg, respectively, P < 0.01). A similar response was produced by hindlimb intra-arterial capsaicin administration to stimulate the metaboreflex arm of the EPR. Thus, our data demonstrate a novel action of dietary Pi loading in augmenting EPR function through overactivation of both the muscle mechanoreflex and metaboreflex.",
keywords = "Blood pressure, Diet, Exercise pressor reflex, Hypertension, Phosphate, Sympathetic nerve activity, Western diet",
author = "Masaki Mizuno and Mitchell, {Jere H.} and Scott Crawford and Huang, {Chou Long} and Naim Maalouf and Hu, {Ming Chang} and Moe, {Orson W.} and Smith, {Scott A.} and Wanpen Vongpatanasin",
year = "2016",
month = "7",
day = "1",
doi = "10.1152/ajpregu.00124.2016",
language = "English (US)",
volume = "311",
pages = "R39--R48",
journal = "American Journal of Physiology - Heart and Circulatory Physiology",
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TY - JOUR

T1 - High dietary phosphate intake induces hypertension and augments exercise pressor reflex function in rats

AU - Mizuno, Masaki

AU - Mitchell, Jere H.

AU - Crawford, Scott

AU - Huang, Chou Long

AU - Maalouf, Naim

AU - Hu, Ming Chang

AU - Moe, Orson W.

AU - Smith, Scott A.

AU - Vongpatanasin, Wanpen

PY - 2016/7/1

Y1 - 2016/7/1

N2 - An increasing number of studies have linked high dietary phosphate (Pi) intake to hypertension. It is well established that the rise in sympathetic nerve activity (SNA) and blood pressure (BP) during physical exertion is exaggerated in many forms of hypertension, which are primarily mediated by an overactive skeletal muscle exercise pressor reflex (EPR). However, it remains unknown whether high dietary Pi intake potentiates the EPR-mediated SNA and BP response to exercise. Accordingly, we measured renal SNA (RSNA) and mean BP (MBP) in normotensive Sprague-Dawley rats fed a normal Pi diet (0.6%, n = 13) or high Pi diet (1.2%, n = 13) for 3 mo. As previously reported, we found that resting BP was significantly increased by 1.2% Pi diet in both conscious and anesthetized animals. Activation of the EPR by electrically induced hindlimb contraction triggered greater increases in ΔRSNA and ΔMBP in the 1.2% compared with 0.6% Pi group (126 ± 25 vs. 42 ± 9%; 44 ± 5 vs. 14 ± 2 mmHg, respectively, P < 0.01). Activation of the muscle mechanoreflex, a component of the EPR, by passively stretching hindlimb muscle also evoked greater increases in ΔRSNA and ΔMBP in the 1.2% compared with 0.6% Pi group (109 ± 27 vs. 24 ± 7%, 38 ± 7 vs. 8 ± 2 mmHg, respectively, P < 0.01). A similar response was produced by hindlimb intra-arterial capsaicin administration to stimulate the metaboreflex arm of the EPR. Thus, our data demonstrate a novel action of dietary Pi loading in augmenting EPR function through overactivation of both the muscle mechanoreflex and metaboreflex.

AB - An increasing number of studies have linked high dietary phosphate (Pi) intake to hypertension. It is well established that the rise in sympathetic nerve activity (SNA) and blood pressure (BP) during physical exertion is exaggerated in many forms of hypertension, which are primarily mediated by an overactive skeletal muscle exercise pressor reflex (EPR). However, it remains unknown whether high dietary Pi intake potentiates the EPR-mediated SNA and BP response to exercise. Accordingly, we measured renal SNA (RSNA) and mean BP (MBP) in normotensive Sprague-Dawley rats fed a normal Pi diet (0.6%, n = 13) or high Pi diet (1.2%, n = 13) for 3 mo. As previously reported, we found that resting BP was significantly increased by 1.2% Pi diet in both conscious and anesthetized animals. Activation of the EPR by electrically induced hindlimb contraction triggered greater increases in ΔRSNA and ΔMBP in the 1.2% compared with 0.6% Pi group (126 ± 25 vs. 42 ± 9%; 44 ± 5 vs. 14 ± 2 mmHg, respectively, P < 0.01). Activation of the muscle mechanoreflex, a component of the EPR, by passively stretching hindlimb muscle also evoked greater increases in ΔRSNA and ΔMBP in the 1.2% compared with 0.6% Pi group (109 ± 27 vs. 24 ± 7%, 38 ± 7 vs. 8 ± 2 mmHg, respectively, P < 0.01). A similar response was produced by hindlimb intra-arterial capsaicin administration to stimulate the metaboreflex arm of the EPR. Thus, our data demonstrate a novel action of dietary Pi loading in augmenting EPR function through overactivation of both the muscle mechanoreflex and metaboreflex.

KW - Blood pressure

KW - Diet

KW - Exercise pressor reflex

KW - Hypertension

KW - Phosphate

KW - Sympathetic nerve activity

KW - Western diet

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