Roles of nitric oxide and angiotensin II in the impaired baroreflex gain of pregnancy

2007 ◽  
Vol 292 (6) ◽  
pp. R2179-R2187 ◽  
Author(s):  
Daisy L. Daubert ◽  
Dongmei Liu ◽  
Irving H. Zucker ◽  
Virginia L. Brooks
Keyword(s):  
Nitric Oxide ◽  
Angiotensin Ii ◽  
Potential Role ◽  
Brain Regions ◽  
Ventrolateral Medulla ◽  
Solitary Tract ◽  
Baroreflex Control ◽  
Protein Levels ◽  
Before And After

The present study tested the hypothesis that nitric oxide (NO) contributes to impaired baroreflex gain of pregnancy and that this action is enhanced by angiotensin II. To test these hypotheses, we quantified baroreflex control of heart rate in nonpregnant and pregnant conscious rabbits before and after: 1) blockade of NO synthase (NOS) with Nω-nitro-l-arginine (20 mg/kg iv); 2) blockade of the angiotensin II AT1 receptor with L-158,809 (5 μg·kg−1·min−1 iv); 3) infusion of angiotensin II (1 ng·kg−1·min−1 nonpregnant, 1.6–4 ng·kg−1·min−1 pregnant iv); 4) combined blockade of angiotensin II AT1 receptors and NOS; and 5) combined infusion of angiotensin II and blockade of NOS. To determine the potential role of brain neuronal NOS (nNOS), mRNA and protein levels were measured in the paraventricular nucleus, nucleus of the solitary tract, caudal ventrolateral medulla, and rostral ventrolateral medulla in pregnant and nonpregnant rabbits. The decrease in baroreflex gain observed in pregnant rabbits (from 23.3 ± 3.6 to 7.1 ± 0.9 beats·min−1·mmHg−1, P < 0.05) was not reversed by NOS blockade (to 8.3 ± 2.5 beats·min−1·mmHg−1), angiotensin II blockade (to 5.0 ± 1.1 beats·min−1·mmHg−1), or combined blockade (to 12.3 ± 4.8 beats·min−1·mmHg−1). Angiotensin II infusion with (to 5.7 ± 1.0 beats·min−1·mmHg−1) or without (to 8.4 ± 2.4 beats·min−1·mmHg−1) NOS blockade also failed to improve baroreflex gain in pregnant or nonpregnant rabbits. In addition, nNOS mRNA and protein levels in cardiovascular brain regions were not different between nonpregnant and pregnant rabbits. Therefore, we conclude that NO, either alone or via an interaction with angiotensin II, is not responsible for decrease in baroreflex gain during pregnancy.

scholarly journals Nitric oxide and angiotensin II regulate cardiovascular homeostasis and the arterial baroreflex control of heart rate in conscious lambs

2011 ◽  
Vol 13 (1) ◽  
pp. 99-106 ◽  
Author(s):  
Stephanie J Wehlage ◽  
Francine G Smith
Keyword(s):  
Nitric Oxide ◽  
Heart Rate ◽  
Angiotensin Ii ◽  
Ang Ii ◽  
Arterial Baroreflex ◽  
Baroreflex Control ◽  
Before And After ◽  
Cardiovascular Homeostasis ◽  
New Evidence

To investigate the potential role of angiotensin II (Ang II) type 1 receptors (AT1Rs) as well as endogenously produced nitric oxide (NO) in regulating cardiovascular homeostasis during ontogeny, experiments were carried out in conscious lambs aged approximately 1 week ( N = 9) and 6 weeks ( N = 11). The arterial baroreflex control of heart rate (HR) was assessed before and after intravenous (IV) infusion of the selective AT1R antagonist, ZD 7155, before and after IV administration of the L-arginine analogue, NG-nitro-L-arginine methyl ester (L-NAME). In both groups, after ZD 7155 alone, mean arterial pressure decreased then increased after L-NAME. At 1 but not 6 weeks, HR decreased after ZD 7155 as well as after L-NAME. At 1 but not 6 weeks, there was a decrease in the HR range after ZD 7155 and after ZD 7155 + L-NAME, as compared to control. There was also a decrease in minimum HR after ZD 7155 + L-NAME at 1 week. These data provide new evidence that, together, Ang II and NO regulate cardiovascular homeostasis as well as the arterial baroreflex of HR early in life which may help to explain the activation of these two systems early in life.

scholarly journals Blockade of neuronal nitric oxide synthase alters the baroreflex control of heart rate in the rabbit

1998 ◽  
Vol 274 (1) ◽  
pp. R181-R186 ◽  
Author(s):  
Hiroshi Murakami ◽  
Jun-Li Liu ◽  
Hirohito Yoneyama ◽  
Yasuhiro Nishida ◽  
Kenji Okada ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Heart Rate ◽  
No Synthase ◽  
Baroreflex Control ◽  
Neuronal No Synthase ◽  
Significant Difference ◽  
Before And After ◽  
Synthase Inhibitor ◽  
Oxide Synthase

In previous studies we used N G-nitro-l-arginine (l-NNA) to investigate the role of nitric oxide (NO) in baroreflex control of heart rate (HR) and renal sympathetic nerve activity (RSNA).l-NNA increased resting mean arterial pressure (MAP), decreased HR, and did not change or slightly decreased RSNA. These changes complicated the assessment of the central effects of NO on the baroreflex control of HR and RSNA. Therefore, in the present study the effects of the relatively selective neuronal NO synthase inhibitor 7-nitroindazole (7-NI) on the baroreflex control of HR and RSNA were investigated in rabbits. Intraperitoneal injection of 7-NI (50 mg/kg) had no effect on resting HR, MAP, or RSNA. 7-NI significantly reduced the lower plateau of the HR-MAP baroreflex curve from 140 ± 4 to 125 ± 4 and from 177 ± 10 to 120 ± 9 beats/min in conscious and anesthetized preparations, respectively ( P < 0.05). In contrast, there was no significant difference in the RSNA-MAP curves before and after 7-NI administration in conscious or anesthetized preparations. These data suggest that blockade of neuronal NO synthase influences baroreflex control of HR but not of RSNA in rabbits.

Role of Nitric Oxide in Short-term and Prolonged Effects of Angiotensin II on Renal Hemodynamics

Hypertension ◽  
1996 ◽  
Vol 27 (5) ◽  
pp. 1173-1179 ◽  
Author(s):  
Xiaolin Deng ◽  
William J. Welch ◽  
Christopher S. Wilcox
Keyword(s):  
Nitric Oxide ◽  
Angiotensin Ii ◽  
Renal Hemodynamics ◽  
Short Term

The potential role of an activity-based guitar program on the anxiety and fulfillment levels of younger relatives of cancer patients: A pilot study

2021 ◽  
pp. 025576142110273
Author(s):  
Erkan Sülün ◽  
Hüseyin Olgaçer ◽  
Hakkı Cengiz Eren
Keyword(s):  
Cancer Patients ◽  
Trait Anxiety ◽  
Potential Role ◽  
Rank Test ◽  
Satisfaction Scale ◽  
Before And After ◽  
Signed Rank Test ◽  
Total State ◽  
Rank Differences

In this study, the authors evaluated the potential role of an activity-based guitar training program on reducing anxiety and providing fulfillment for younger relatives of cancer patients. Ten active members of KHYD (The Society for Relatives of Cancer Patients), between ages 11 and 17 participated in an 8-week guitar education program. The participants filled out two questionnaires before and after their engagement in the 8-week program, one to measure changes in their anxiety levels (State-Trait Anxiety Inventory) and the other to measure changes in their general fulfillment levels (Multidimensional Students’ Life Satisfaction Scale). Wilcoxon signed rank test, as well as descriptive statistics were used in the analysis of data. Mean rank differences were observed to be statistically significant with respect to total state and trait anxiety scores; in both cases, the participants’ scores decreased after their engagement in the program. Statistically significant mean rank differences were also observed in the overall MSLSS scores and its “friends” and “environment” sub-dimensions; with respect to these, participants’ scores increased after their engagement in the program. Recommendations for more comprehensive, larger-scale studies are given at the end.

Systemic and regional hemodynamics after nitric oxide synthase inhibition: role of a neurogenic mechanism

1994 ◽  
Vol 267 (1) ◽  
pp. R84-R88 ◽  
Author(s):  
M. Huang ◽  
M. L. Leblanc ◽  
R. L. Hester
Keyword(s):  
Nitric Oxide ◽  
Blood Pressure ◽  
Cardiac Output ◽  
No Synthase ◽  
Before And After ◽  
Regional Hemodynamics ◽  
Autonomic Blockade ◽  
Infusion Of Norepinephrine ◽  
Oxide Synthase

The study tested the hypothesis that the increase in blood pressure and decrease in cardiac output after nitric oxide (NO) synthase inhibition with N omega-nitro-L-arginine methyl ester (L-NAME) was partially mediated by a neurogenic mechanism. Rats were anesthetized with Inactin (thiobutabarbital), and a control blood pressure was measured for 30 min. Cardiac output and tissue flows were measured with radioactive microspheres. All measurements of pressure and flows were made before and after NO synthase inhibition (20 mg/kg L-NAME) in a group of control animals and in a second group of animals in which the autonomic nervous system was blocked by 20 mg/kg hexamethonium. In this group of animals, an intravenous infusion of norepinephrine (20-140 ng/min) was used to maintain normal blood pressure. L-NAME treatment resulted in a significant increase in mean arterial pressure in both groups. L-NAME treatment decreased cardiac output approximately 50% in both the intact and autonomic blocked animals (P < 0.05). Autonomic blockade alone had no effect on tissue flows. L-NAME treatment caused a significant decrease in renal, hepatic artery, stomach, intestinal, and testicular blood flow in both groups. These results demonstrate that the increase in blood pressure and decreases in cardiac output and tissue flows after L-NAME treatment are not dependent on a neurogenic mechanism.

Role of Nitric Oxide Synthase Uncoupling at Rostral Ventrolateral Medulla in Redox-Sensitive Hypertension Associated With Metabolic Syndrome

Hypertension ◽  
2014 ◽  
Vol 64 (4) ◽  
pp. 815-824 ◽  
Author(s):  
Kay L.H. Wu ◽  
Yung-Mei Chao ◽  
Shiow-Jen Tsay ◽  
Chen Hsiu Chen ◽  
Samuel H.H. Chan ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Metabolic Syndrome ◽  
Nitric Oxide Synthase ◽  
Rostral Ventrolateral Medulla ◽  
Ventrolateral Medulla ◽  
Oxide Synthase

Impaired responsiveness to angiotensin II in experimental cirrhosis: Role of nitric oxide

Hepatology ◽  
1993 ◽  
Vol 18 (2) ◽  
pp. 367-372 ◽  
Author(s):  
Anna Castro ◽  
Wladimiro Jiménez ◽  
Joan Clária ◽  
Josefa Ros ◽  
Josep Maria Martínez ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Angiotensin Ii ◽  
Experimental Cirrhosis

Nitric oxide: a new role in intensive care

2020 ◽  
Vol 22 (1) ◽  
pp. 72-79
Author(s):  
Alexandra Lee ◽  
◽  
Warwick Butt ◽  
◽  
◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Potential Role ◽  
Nitric Oxide Donors ◽  
Ischaemia Reperfusion Injury ◽  
Surface Receptors ◽  
The Past ◽  
Ischaemia Reperfusion ◽  
Human Experiments ◽  
Endogenous Nitric Oxide

Inhaled nitric oxide has been used for 30 years to improve oxygenation and decrease pulmonary vascular resistance. In the past 15 years, there has been increased understanding of the role of endogenous nitric oxide on cell surface receptors, mitochondria, and intracellular processes involving calcium and superoxide radicals. This has led to several animal and human experiments revealing a potential role for administered nitric oxide or nitric oxide donors in patients with systemic inflammatory response syndrome or ischaemia–reperfusion injury, and in patients for whom exposure of blood to artificial surfaces has occurred.

Losartan Increases No Production from the Bovine Aortic Wall That is Stimulated by Angiotensin II

2003 ◽  
Vol 1 (3) ◽  
pp. 113-117 ◽  
Author(s):  
M. Myronidou ◽  
B. Kokkas ◽  
A. Kouyoumtzis ◽  
N. Gregoriadis ◽  
A. Lourbopoulos ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Angiotensin Ii ◽  
Aortic Wall ◽  
Vascular Wall ◽  
Protective Role ◽  
Normal Function ◽  
No Production ◽  
Chemical Inactivation

In these studies we investigated if losartan, an AT1- receptor blocker has any beneficial effect on NO production from the bovine aortic preparations in vitro while under stimulation from angiotensin II. Experiments were performed on intact specimens of bovine thoracic aorta, incubated in Dulbeco's MOD medium in a metabolic shaker for 24 hours under 95 % O2 and 5 % CO2 at a temperature of 37°C. We found that angiotensin II 1nM−10 μM does not exert any statistically significant action on NO production. On the contrary, angiotensin II 10nM increases the production of NO by 58.14 % (from 12.16 + 2.9 μm/l to 19.23 + 4.2 μm/l in the presence of losartan 1nM (P<0.05). Nitric oxide levels depend on both rate production and rate catabolism or chemical inactivation. Such an equilibrium is vital for the normal function of many systems including the cardiovascular one. The above results demonstrate that the blockade of AT1-receptors favors the biosynthesis of NO and indicate the protective role of losartan on the vascular wall.

scholarly journals Duodenal Dysbiosis and Relation to the Efficacy of Proton Pump Inhibitors in Functional Dyspepsia

2021 ◽  
Vol 22 (24) ◽  
pp. 13609
Author(s):  
Lucas Wauters ◽  
Raúl Y. Tito ◽  
Matthias Ceulemans ◽  
Maarten Lambaerts ◽  
Alison Accarie ◽  
...  
Keyword(s):  
Functional Dyspepsia ◽  
Proton Pump Inhibitors ◽  
Proton Pump ◽  
Potential Role ◽  
Short Term ◽  
Beneficial Effects ◽  
Rrna Sequencing ◽  
Before And After

Proton pump inhibitors (PPI) may improve symptoms in functional dyspepsia (FD) through duodenal eosinophil-reducing effects. However, the contribution of the microbiome to FD symptoms and its interaction with PPI remains elusive. Aseptic duodenal brushings and biopsies were performed before and after PPI intake (4 weeks Pantoprazole 40 mg daily, FD-starters and controls) or withdrawal (2 months, FD-stoppers) for 16S-rRNA sequencing. Between- and within-group changes in genera or diversity and associations with symptoms or duodenal factors were analyzed. In total, 30 controls, 28 FD-starters and 19 FD-stoppers were followed. Mucus-associated Porphyromonas was lower in FD-starters vs. controls and correlated with symptoms in FD and duodenal eosinophils in both groups, while Streptococcus correlated with eosinophils in controls. Although clinical and eosinophil-reducing effects of PPI therapy were unrelated to microbiota changes in FD-starters, increased Streptococcus was associated with duodenal PPI effects in controls and remained higher despite withdrawal of long-term PPI therapy in FD-stoppers. Thus, duodenal microbiome analysis demonstrated differential mucus-associated genera, with a potential role of Porphyromonas in FD pathophysiology. While beneficial effects of short-term PPI therapy were not associated with microbial changes in FD-starters, increased Streptococcus and its association with PPIeffects in controls suggest a role for duodenal dysbiosis after long-term PPI therapy.

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