Reduced plasma noradrenaline during angiotensin II-induced acute hypertension in man

1985 ◽  
Vol 68 (6) ◽  
pp. 621-624 ◽  
Author(s):  
Jens H. Henriksen ◽  
Jens Kastrup ◽  
Niels Juel Christensen
Keyword(s):  
Angiotensin Ii ◽  
Intravenous Infusion ◽  
Plasma Noradrenaline ◽  
Ang Ii ◽  
Acute Hypertension ◽  
Plasma Adrenaline ◽  
Ganglionic Blockade ◽  
Arterial Blood ◽  
Sympathoadrenal Activity ◽  
Noradrenaline And Adrenaline

1. Plasma noradrenaline and adrenaline concentrations were measured in ten subjects before, during and after intravenous infusion of angiotensin II (ANG II) in order to determine the sympathoadrenal response of ANG II challenge in man. In five subjects ganglionic blockade was additionally performed by intravenous infusion of trimethaphan. 2. During ANG II infusion mean arterial blood pressure increased by 30% (P<0.001), and plasma noradrenaline decreased by 25% (P<0.001). Plasma adrenaline decreased less. 3. During ganglionic blockade plasma noradrenaline decreased significantly (P<0.005) and similarly to the decrease obtained with ANG II infusion. 4. The results indicate that a decrease in sympathoadrenal activity occurs during ANG II-induced acute hypertension in man. This may be elicited by the arterial baroreflex, which seems to dominate any direct sympathoadrenergic facilitating effect of ANG II.

Angiotensin II acutely attenuates range of arterial baroreflex control of renal sympathetic nerve activity

2000 ◽  
Vol 279 (4) ◽  
pp. H1804-H1812 ◽  
Author(s):  
Max G. Sanderford ◽  
Vernon S. Bishop
Keyword(s):  
Angiotensin Ii ◽  
Sympathetic Nerve ◽  
Intravenous Infusion ◽  
Sympathetic Nerve Activity ◽  
Ang Ii ◽  
Nerve Activity ◽  
Renal Sympathetic Nerve Activity ◽  
Renal Sympathetic Nerve ◽  
Arterial Blood ◽  
Renal Sympathetic

Acutely increasing peripheral angiotensin II (ANG II) reduces the maximum renal sympathetic nerve activity (RSNA) observed at low mean arterial blood pressures (MAPs). We postulated that this observation could be explained by the action of ANG II to acutely increase arterial blood pressure or increase circulating arginine vasopressin (AVP). Sustained increases in MAP and increases in circulating AVP have previously been shown to attenuate maximum RSNA at low MAP. In conscious rabbits pretreated with an AVP V1 receptor antagonist, we compared the effect of a 5-min intravenous infusion of ANG II (10 and 20 ng · kg−1 · min−1) on the relationship between MAP and RSNA when the acute pressor action of ANG II was left unopposed with that when the acute pressor action of ANG II was opposed by a simultaneous infusion of sodium nitroprusside (SNP). Intravenous infusion of ANG II resulted in a dose-related attenuation of the maximum RSNA observed at low MAP. When the acute pressor action of ANG II was prevented by SNP, maximum RSNA at low MAP was attenuated, similar to that observed when ANG II acutely increased MAP. In contrast, intravertebral infusion of ANG II attenuated maximum RSNA at low MAP significantly more than when administered intravenously. The results of this study suggest that ANG II may act within the central nervous system to acutely attenuate the maximum RSNA observed at low MAP.

Angiotensin II-stimulated secretion of arginine vasopressin is inhibited by atrial natriuretic peptide in humans

2011 ◽  
Vol 300 (3) ◽  
pp. R624-R629 ◽  
Author(s):  
Toshiyoshi Matsukawa ◽  
Takenori Miyamoto
Keyword(s):  
Blood Pressure ◽  
Angiotensin Ii ◽  
Atrial Natriuretic Peptide ◽  
Natriuretic Peptide ◽  
Arginine Vasopressin ◽  
Intravenous Infusion ◽  
Ang Ii ◽  
Blood Pressure Elevation ◽  
Arterial Blood ◽  
Atrial Natriuretic

We investigated the effect of the intravenous infusion of atrial natriuretic peptide (ANP) on the response of plasma arginine vasopressin (AVP) levels to intravenous infusion of angiotensin II (ANG II) in healthy individuals. Intravenous infusion of ANP (10 ng·kg−1·min−1) slightly but significantly decreased plasma AVP levels, while intravenous infusion of ANG II (10 ng·kg−1·min−1) resulted in slightly increased plasma AVP levels. ANG II infused significant elevations in arterial blood pressure and central venous pressure (CVP). Because the elevation in blood pressure could have potentially inhibited AVP secretion via baroreceptor reflexes, the effect of ANG II on blood pressure was attenuated by the simultaneous infusion of nitroprusside. ANG II alone produced a remarkable increase in plasma AVP levels when infused with nitroprusside, whereas the simultaneous ANP intravenous infusion (10 ng·kg−1·min−1) abolished the increase in plasma AVP levels induced by ANG II when blood pressure elevation was attenuated by nitroprusside. Thus, ANG II increased AVP secretion and ANP inhibited not only basal AVP secretion but also ANG II-stimulated AVP secretion in humans. These findings support the hypothesis that circulating ANP modulates AVP secretion, in part, by antagonizing the action of circulating ANG II.

Acute hypertension inhibits thirst stimulated by ANG II, hyperosmolality, or hypovolemia in rats

2001 ◽  
Vol 280 (1) ◽  
pp. R214-R224 ◽  
Author(s):  
Sean D. Stocker ◽  
Edward M. Stricker ◽  
Alan F. Sved
Keyword(s):  
Arterial Pressure ◽  
Intravenous Infusion ◽  
Drinking Behavior ◽  
Plasma Osmolality ◽  
Plasma Renin ◽  
Ang Ii ◽  
Plasma Protein Concentration ◽  
Acute Hypertension ◽  
Arterial Blood ◽  
Phenylephrine Infusion

The present study sought to determine whether increases in arterial blood pressure inhibited drinking behavior evoked by ANG II, hyperosmolality, or hypovolemia in rats. Cumulative water intakes in 60- or 90-min tests and latency to the first lick were recorded as indexes of thirst. During intravenous infusions of 100 ng · kg−1 · min−1 ANG II, attenuation of the induced increases in arterial pressure with the arteriolar vasodilator diazoxide resulted in greater water intakes and shorter latencies to drink. Drinking behavior stimulated by intravenous infusion of hypertonic saline was significantly inhibited by increases in arterial pressure caused by intravenous infusion of phenylephrine or endothelin-1, and this inhibition of drinking was proportional to the induced increase in pressure. Upon termination of the phenylephrine infusion, mean arterial pressure returned to basal values, and drinking was restored. Phenylephrine-induced increases in arterial pressure also inhibited drinking behavior in response to hypovolemia that could not be explained by differences in plasma renin activity, plasma protein concentration, or plasma osmolality. Thus increases in arterial pressure inhibit water drinking behavior in response to each of these three thirst stimuli in rats.

Rapid elicitation of salt appetite by an intravenous infusion of angiotensin II in rats

1996 ◽  
Vol 270 (5) ◽  
pp. R1092-R1098 ◽  
Author(s):  
D. A. Fitts ◽  
R. L. Thunhorst
Keyword(s):  
Blood Pressure ◽  
Angiotensin Ii ◽  
Intravenous Infusion ◽  
Enzyme Inhibitor ◽  
Direct Action ◽  
Renin Angiotensin System ◽  
Salt Appetite ◽  
Ang Ii ◽  
Direct Stimulation ◽  
Arterial Blood

A role for the renal renin-angiotensin system in the direct stimulation of salt appetite in the rat remains controversial because attempts to elicit the behavior by intravenous administration of angiotensin II (ANG II) have been unconvincing. We recently demonstrated that depletion-induced salt appetite was attenuated by selective blockade of peripheral ANG II synthesis with an intravenous dose of converting enzyme inhibitor [captopril (Cap)] that does not block the synthesis of ANG II inside the blood brain barrier. We now show that intravenous ANG II at 30 ng/min rapidly reestablishes salt appetite in Cap-blocked rats. The mean arterial blood pressure (MAP) of unblocked, sodium-depleted rats was normal, but Cap-blocked, depleted rats had low MAP. An intravenous infusion of ANG II in Cap-blocked rats brought MAP into the normal range and elicited water and salt drinking within 90 min. Phenylephrine also normalized MAP but failed to elicit fluid intake in Cap-blocked, sodium-deficient rats. Sodium and water balances tended to be more positive during ANG II than during phenylephrine infusions. Thus circulating ANG II may stimulate both thirst and salt appetite by a direct action on the brain and not by causing natriuresis or by raising the blood pressure.

Interactions of physiological and pharmacological concentrations of ANP and angiotensin II in conscious dogs

1992 ◽  
Vol 263 (3) ◽  
pp. R537-R543
Author(s):  
R. Kuhlen ◽  
H. Seibt ◽  
R. Engel ◽  
G. Kaczmarczyk
Keyword(s):  
Angiotensin Ii ◽  
Intravenous Infusion ◽  
Sodium Intake ◽  
Venous Pressure ◽  
Urine Volume ◽  
Dietary Sodium ◽  
Ang Ii ◽  
Mediated Effects ◽  
Arterial Blood ◽  
Chronically Instrumented Dogs

This study in conscious, chronically instrumented dogs investigated the effects of human atrial natriuretic peptide [hANP-(99-126)] at physiological (5 ng.kg-1.min-1) and pharmacological (5-900 ng.kg-1.min-1) doses on angiotensin II (ANG II)-mediated effects on hemodynamics, renal excretion, and aldosterone release. Five female beagle dogs kept chronically on a dietary sodium intake of 2.5 mmol Na.kg body wt-1.day-1 received an intravenous infusion of 1, 4, 10, 20, and 50 ng.kg-1.min-1 ANG II (20-min periods) without (protocol 1) or with (protocol 2) simultaneous intravenous infusion of 5 ng.kg-1.min-1 hANP-(99-126). In protocol 1, glomerular filtration rate (means +/- SD) decreased from 4.0 +/- 0.6 to 2.8 +/- 0.5 ml.kg-1.min-1, renal sodium excretion (UNaV) decreased from 2.8 +/- 1.6 to 0.4 +/- 0.2 mumol.kg-1.min-1, and urine volume (V) decreased from 45 +/- 23 to 6 +/- 8 microliters.kg-1.min-1. There were no differences in the values between protocol 1 and protocol 2. Mean arterial blood pressure (MABP) increased similarly from 118 +/- 16 to 166 +/- 9 mmHg in protocol 1 and from 109 +/- 11 to 162 +/- 7 mmHg in protocol 2. Maximal aldosterone secretion was stimulated less in protocol 2 (481 +/- 92 vs. 362 +/- 158 pg/ml; P less than 0.05). In ANG II-pretreated (20 ng.kg-1.min-1) dogs (n = 4; protocol 3), intravenous hANP-(99-126) doses of 300-900 ng.kg-1.min-1 decreased MABP and central venous pressure.(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals Endoplasmic reticulum and oxidant stress mediate nuclear factor-κB activation in the subfornical organ during angiotensin II hypertension

2015 ◽  
Vol 308 (10) ◽  
pp. C803-C812 ◽  
Author(s):  
Colin N. Young ◽  
Anfei Li ◽  
Frederick N. Dong ◽  
Julie A. Horwath ◽  
Catharine G. Clark ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Endoplasmic Reticulum ◽  
Transcription Factor ◽  
Angiotensin Ii ◽  
Er Stress ◽  
Bioluminescence Imaging ◽  
Nuclear Factor Κb ◽  
Nuclear Factor ◽  
Ang Ii ◽  
Arterial Blood

Endoplasmic reticulum (ER) stress and reactive oxygen species (ROS) generation in the brain circumventricular subfornical organ (SFO) mediate the central hypertensive actions of Angiotensin II (ANG II). However, the downstream signaling events remain unclear. Here we tested the hypothesis that angiotensin type 1a receptors (AT1aR), ER stress, and ROS induce activation of the transcription factor nuclear factor-κB (NF-κB) during ANG II-dependent hypertension. To spatiotemporally track NF-κB activity in the SFO throughout the development of ANG II-dependent hypertension, we used SFO-targeted adenoviral delivery and longitudinal bioluminescence imaging in mice. During low-dose infusion of ANG II, bioluminescence imaging revealed a prehypertensive surge in NF-κB activity in the SFO at a time point prior to a significant rise in arterial blood pressure. SFO-targeted ablation of AT1aR, inhibition of ER stress, or adenoviral scavenging of ROS in the SFO prevented the ANG II-induced increase in SFO NF-κB. These findings highlight the utility of bioluminescence imaging to longitudinally track transcription factor activation during the development of ANG II-dependent hypertension and reveal an AT1aR-, ER stress-, and ROS-dependent prehypertensive surge in NF-κB activity in the SFO. Furthermore, the increase in NF-κB activity before a rise in arterial blood pressure suggests a causal role for SFO NF-κB in the development of ANG II-dependent hypertension.

Abstract 065: Overexpression of an Intracellular Angiotensin II Fusion Protein Selectively in the Mitochondria of the Proximal Tubules Elevates Blood Pressure in Mice via AT 1a Receptor-mediated Mitochondrial Respiratory and Glycolysis Stress

Hypertension ◽  
2016 ◽  
Vol 68 (suppl_1) ◽  
Author(s):  
Xiao C Li ◽  
Manoocher Soleimani ◽  
Hoang Nguyen ◽  
Hong Li ◽  
Jia L Zhuo
Keyword(s):  
Blood Pressure ◽  
Angiotensin Ii ◽  
Fusion Protein ◽  
Proximal Tubule ◽  
Physiological Role ◽  
Proximal Tubules ◽  
Ang Ii ◽  
Stress Tests ◽  
Arterial Blood ◽  
Mitochondrial Respiratory

An intracrine mitochondrial renin-angiotensin system (RAS) has recently been identified in various animal and human tissues, but whether the mitochondrial RAS plays a physiological role in the regulation of blood pressure remains unknown. The present study tested whether overexpression of an intracellular angiotensin II fusion protein, ECFP/ANG II, selectively in the mitochondria of the proximal tubules alters blood pressure, and whether the effects may involve AT 1a receptors and the Na + /H + exchanger 3 (NHE3). An adenoviral vector encoding ECFP/ANG II, a mitochondria targeting sequence, and the sglt2 promoter, Ad-sglt2-mito-ECFP/ANG II, was constructed for proximal tubule- and mitochondria-specific overexpression for 2 weeks. In adult male C57BL/6J mice, overexpression of mito-ECFP/ANG II in the mitochondria of the proximal tubules increased systolic blood pressure (SBP) significantly (Control: 116 ± 3 vs. mito-ECFP/ANG II: 128 ± 3 mmHg; p <0.01, n=15). The blood pressure-increasing effect of Ad-sglt2-mito-ECFP/ANG II was blocked in proximal tubule-specific AT 1a -KO mice (Control: 105 ± 2 vs. mito-ECFP/ANG II: 104 ± 4 mmHg; n.s ., n=7), or in proximal tubule-specific NHE3-KO mice (Control: 108 ± 3 vs. mito-ECFP/ANG II: 107 ± 3 mmHg; n.s ., n=13), respectively. In further experiments, mouse proximal tubule cells were transfected with Ad-sglt2-mito-ECFP/ANG II for 48 h and treated with the AT 1 blocker losartan (10 μM) or the AT 2 blocker PD123319 (10 μM) to measure mitochondrial respiratory and glycolytic function using Seahorse XF Cell Mito and XF Glycolysis Stress Tests. The mito-ECFP/ANG II expression was robust and colocalized with MitoTracker® Red FM. Overexpression of mito-ECFP/ANG II markedly increased oxygen consumption rate (OCR) (Control: 139.4 ± 9.2 vs. mito-ECFP/ANG II: 236.3 ± 12.6 pmol/min; p <0.01, n=12) and extracellular acidification rate (ECAR) (Control: 8.8 ± 0.6 vs. mito-ECFP/ANG II: 11.8 ± 1.2 mpH/min; p <0.01, n=12), respectively. Losartan blocked the effects of mito-ECFP/ANG II on OCR and ECAR, whereas PD123319 had no effect. We conclude that intracellular ANG II may activate AT 1 receptors in the mitochondria of the proximal tubules to alter mitochondrial respiratory and glycolytic function and arterial blood pressure.

Role of arteria baroreceptor input on thirst and urinary responses to intracerebroventricular angiotensin II

1993 ◽  
Vol 265 (3) ◽  
pp. R591-R595 ◽  
Author(s):  
R. L. Thunhorst ◽  
S. J. Lewis ◽  
A. K. Johnson
Keyword(s):  
Blood Pressure ◽  
Angiotensin Ii ◽  
Arterial Blood Pressure ◽  
Water Intake ◽  
Enzyme Inhibitor ◽  
Ang Ii ◽  
Converting Enzyme ◽  
Arterial Blood ◽  
Endogenous Formation

Intracerebroventricular (icv) infusion of angiotensin II (ANG II) in rats elicits greater water intake under hypotensive, compared with normotensive, conditions. The present experiments used sinoaortic baroreceptor-denervated (SAD) rats and sham-operated rats to examine if the modulatory effects of arterial blood pressure on water intake in response to icv ANG II are mediated by arterial baroreceptors. Mean arterial blood pressure (MAP) was raised or lowered by intravenous (i.v.) infusions of phenylephrine (1 or 10 micrograms.kg-1 x min-1) or minoxidil (25 micrograms.kg-1 x min-1), respectively. The angiotensin-converting enzyme inhibitor captopril (0.33 mg/min) was infused i.v. to prevent the endogenous formation of ANG II during testing. Urinary excretion of water and solutes was measured throughout. Water intake elicited by icv ANG II was inversely related to changes in MAP. Specifically, rats drank more water in response to icv ANG II when MAP was reduced by minoxidil but drank less water when MAP was elevated by phenylephrine. The influence of changing MAP on the icv ANG II-induced drinking responses was not affected by SAD. These results suggest that the modulatory effects of arterial blood pressure on icv ANG II-induced drinking can occur in the absence of sinoaortic baroreceptor input.

Hypertension in insulin-resistant Zucker obese rats is independent of sympathetic neural support

1992 ◽  
Vol 262 (3) ◽  
pp. E368-E371 ◽  
Author(s):  
M. B. Zemel ◽  
J. D. Peuler ◽  
J. R. Sowers ◽  
L. Simpson
Keyword(s):  
Angiotensin Ii ◽  
Neural Activity ◽  
Vascular Reactivity ◽  
Zucker Rats ◽  
Ganglionic Blockade ◽  
Intravenous Injections ◽  
Insulin Resistant ◽  
Arterial Blood ◽  
Obese Rats ◽  
Blood Pressure Responses

We have previously reported that insulin-resistant Zucker obese rats exhibit hypertension associated with impaired vascular smooth muscle (VSM) Ca2+ transport and proposed that this results from failure of insulin to regulate VSM Ca2+ transport in insulin resistance. However, hypertension in insulin-resistant states is generally attributed to hyperinsulinemia, with a consequent stimulation of sympathetic neural activity. Accordingly, the present study was conducted to determine whether the hypertension observed in Zucker obese rats compared with their lean controls was dependent on either increased sympathetic neural activity or exaggerated vascular reactivity. Intra-arterial blood pressure responses to ganglionic blockade with Ecolid (chlorisondamine chloride) and to graded intravenous injections of angiotensin II and norepinephrine were compared in 6- to 8-wk-old male Zucker rats and their lean controls (n = 10/group). The obese rats exhibited significant hypertension before ganglionic blockade (P less than 0.001), and this difference was largely sustained during ganglionic blockade (P less than 0.005). Furthermore, the obese rats exhibited greater pressor sensitivity to both angiotensin II and to norepinephrine during ganglionic blockade (P less than 0.01). Thus enhanced pressor sensitivity, independent of sympathetic neural activity, appears to support hypertension in Zucker obese rats.

Effect of intravenous angiotensin II on Fos distribution and drinking behavior in rabbits

1997 ◽  
Vol 272 (5) ◽  
pp. R1515-R1524 ◽  
Author(s):  
E. Badoer ◽  
D. McKinlay
Keyword(s):  
Blood Pressure ◽  
Angiotensin Ii ◽  
Intravenous Infusion ◽  
Drinking Behavior ◽  
Ventrolateral Medulla ◽  
Lamina Terminalis ◽  
Ang Ii ◽  
Solitary Tract ◽  
Cell Nuclei ◽  
Drinking Response

We investigated the effect of intravenous infusion of angiotensin II (ANG II, 40 ng.kg-1.min-1) on the distribution of Fos in the subfornical organ (SFO), organum vasculosum of the lamina terminalis (OVLT), and the medulla of the conscious rabbit. ANG II elicited significant increases in the number of Fos-positive cell nuclei in the SFO and OVLT (15- and 10-fold, respectively). Raising blood pressure with phenylephrine did not elicit Fos in these nuclei. These nuclei are believed to be responsible for the dipsogenic actions of ANG II; however, ANG II was not dipsogenic. When blood pressure was held at preinfusion levels by the coadministration of sodium nitroprus-side and ANG II, the rabbits did not drink but Fos production in the lamina terminalis was elevated. In the medulla, ANG II did not significantly increase Fos production in the nucleus of the solitary tract (NTS) or ventrolateral medulla (VLM). However, with the coadministration of sodium nitroprusside, there were marked increases in the NTS and VLM. The results suggest that neurons in the SFO and OVLT are either not involved in the dipsogenic pathways or there is disruption further downstream in the central pathways that would normally mediate a drinking response to ANG II.

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