Sodium Paradoxically Reduces the Gastropressor Response in Patients With Orthostatic Hypotension

Raj, Satish R.; Biaggioni, Italo; Black, Bonnie K.; Rali, Aniket S; Jordan, Jens; Taneja, Indu; Harris, Paul A.; Robertson, David

doi:10.1161/01.hyp.0000229906.27330.4f

Cited by 61 publications

(60 citation statements)

References 32 publications

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“…1 The haemodynamic responses to water ingestion may also be influenced by its osmotic properties, 23 because the pressor effect of salt water is smaller than pure water. 24 The increase in diastolic blood pressure after water ingestion found in hypertensive and normotensive subjects was similar to that observed in patients with multiple system atrophy and pure autonomic failure with sympathetic denervation. 1 In agreement with previous observations, 25 our subjects with mild hypertension showed higher baseline MSNA when compared to normotensive subjects.…”

Section: Discussionsupporting

confidence: 74%

Acute water ingestion increases arterial blood pressure in hypertensive and normotensive subjects

et al. 2007

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In patients with severe autonomic dysfunction, water ingestion elicits an acute pressor response. Hypertension may be associated with changes in cardiovascular autonomic modulation, but there is no information on the acute effects of water ingestion in patients with hypertension. In this study, we compared the effect of acute water ingestion on haemodynamic and autonomic responses of hypertensive and normotensive individuals. Eight patients with mild hypertension were compared to 10 normotensive individuals. After 30 min resting in the supine position all subjects ingested 500 ml of water. At baseline and after water ingestion, venous blood samples for plasma volume determination were collected, and electrocardiographic tracings, finger blood pressure, forearm blood flow and muscle sympathetic nerve activity (MSNA) were obtained. Water ingestion resulted in similar and minor reduction in plasma volume. Systolic and diastolic blood pressure increased in both hypertensive (mean7s.d.: 19/1476/ 3 mm Hg) and normotensive subjects (17/1476/3 mm Hg). There was an increase in forearm vascular resistance and in MSNA. Heart rate was reduced (hypertensive: 571 beats/min, normotensive: 576 beats/min) and the high-frequency component of heart rate and systolic blood pressure variability was increased. In hypertensive and normotensive individuals, acute water ingestion elicits a pressor response, an effect that is most likely determined by an increased vasoconstrictor sympathetic activity, and is counterbalanced by an increase in blood pressure and heart rate vagal modulation.

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Section: Discussionsupporting

confidence: 74%

Acute water ingestion increases arterial blood pressure in hypertensive and normotensive subjects

et al. 2007

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“…23 Previous studies have demonstrated that ingesting water may lower portal plasma osmolality to a greater extent than systemic plasma osmolality to produce the OPR because the intraduodenal saline infusion does not alter portal/systemic osmolality or raise BP in patient with autonomic failure. 8,17 Our study demonstrated there was an excellent correlation between the increase of the AQP1 tyrosine phosphorylation on RBC membrane and the increase of TPR at 25th min after Figure 1. Plasma osmolality decreased after ingestion of 500 mL water at 25 minutes.…”

Section: Discussionsupporting

confidence: 54%

“…1 Hydration status may affect BP, but acutely increasing plasma volume via an intravenous saline infusion fails to elicit the pressor response seen with duodenal water administration. 17 The absence of a pressor response after a saline infusion via nasogastric tube makes luminal stretch an unlikely explanation for the increase Values are the mean (SD). CI indicates cardiac index; DBP, diastolic blood pressure; MABP, mean arterial blood pressure; SBP, systolic blood pressure; SkBF, laser Doppler skin blood flow; SV, stroke volume; and TPR, total peripheral vascular resistance.…”

Section: Discussionmentioning

confidence: 99%

The Osmopressor Response Is Linked to Upregulation of Aquaporin-1 Tyrosine Phosphorylation on Red Blood Cell Membranes

Chu

Hsu²,

Lee³

et al. 2013

Hypertension

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P revious studies in patients with an impaired efferent baroreflex led us to discover that water ingestion induces a robust increase in blood pressure (BP) and vascular resistance.1,2 Initially, Jordan et al 1 demonstrated that ingesting 473 mL (16 oz) of water induces a profound increase in systolic BP averaging ≈40 mm Hg in patients with autonomic failure and also elevated BP by ≈11 mm Hg in elderly subjects. This effect appears within 10 minutes, is maximal at 25 to 40 minutes, and largely dissipates by 90 minutes after water ingestion.1 Although the pressor effect of water is greatest in individuals with impaired baroreflex buffering, water induces a maximal rise in peripheral vascular resistance at 25 minutes after ingestion without an associated increase in BP in young healthy subjects. [3][4][5] This prominent vascular response after water ingestion is termed the osmopressor response (OPR), reflecting that the stimulus setting of the response is hypo-osmolality rather than gastric distension. 6,7 The hypo-osmotic stimulus of water has been thought to act through the osmosensitive structures in portal and splanchnic circulation. 8 In animals, the osmopressor response seems to be mediated through transient receptor potential cation channel, subfamily V, member 4 (TRPV4) activation on osmosensitive hepatic spinal afferents, dorsal horn ganglia, and spinal cord. Aquaporin-1 (AQP1), the first discovered water channel protein, was found colocalized with portal osmosensor TRPV4 in the plasma membrane of axons and synaptic terminals in the superficial dorsal horn and the enteric plexus. 10 We supposed that the AQP1, driven by osmotic gradients, contributes to the osmopressor response by acting as an osmotic sensing input carried by circulating red blood cells (RBCs).Thus, we hypothesized water ingestion induces functional expression of the AQP1 in circulating RBC during the osmopressor response.11 The study presented here demonstrates that the hypo-osmotic stimulus of water increases AQP1 tyrosine phosphorylation simultaneously with the osmopressor response.Abstract-Studies in patients with an impaired efferent baroreflex led us to discover that ingesting water induces a robust increase in blood pressure and vascular resistance. This response was also present in healthy subjects with intact baroreflexes, described as osmopressor response. This study was to discover the physiology of the osmopressor response by determining functional activation of the aquaporin-1 water channel receptor on red blood cell membranes in young healthy subjects. In a randomized, controlled, crossover fashion, 22 young healthy subjects (age, 19-27 years) ingested either 500 or 50 mL of water. Heart rate, blood pressure, cardiac index, and total peripheral vascular resistance were measured using a Finometer hemodynamic monitor. Blood sampling was performed at 5 minutes before and at 25 and 50 minutes after either the water ingestion or control session. Immunoblotting for aquaporin-1 tyrosine phosphorylation was performed before and after ...

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“…396,398,[439][440][441][442][443][444] Salt supplementation (eg, 6 to 9 g [100 to 150 mmol; about 1 to 2 teaspoons] of salt per day) increases plasma volume, with limited benefit in patients with already high salt intake. 396 Water ingestion increases the blood pressure via a pressor effect, most likely mediated by sympathetic activation, with a peak effect approximately 30 minutes after ingestion.…”

Section: 398441443444mentioning

confidence: 99%

2017 ACC/AHA/HRS Guideline for the Evaluation and Management of Patients With Syncope: A Report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines and the Heart Rhythm Society

Sheldon²,

et al. 2017

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Sodium Paradoxically Reduces the Gastropressor Response in Patients With Orthostatic Hypotension

Cited by 61 publications

References 32 publications

Acute water ingestion increases arterial blood pressure in hypertensive and normotensive subjects

Acute water ingestion increases arterial blood pressure in hypertensive and normotensive subjects

The Osmopressor Response Is Linked to Upregulation of Aquaporin-1 Tyrosine Phosphorylation on Red Blood Cell Membranes

2017 ACC/AHA/HRS Guideline for the Evaluation and Management of Patients With Syncope: A Report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines and the Heart Rhythm Society

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