Abstract P200: Role of Macula Densa Neuronal Nitric Oxide Synthase in Control of Renin Release and Blood Pressure Recovery Following Hemorrhagic Shock

Hypertension ◽  
2016 ◽  
Vol 68 (suppl_1) ◽  
Author(s):  
Lei Wang ◽  
Shaohui Wang ◽  
Jacentha Buggs ◽  
Jie Zhang ◽  
Jin Wei ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Blood Pressure ◽  
Hemorrhagic Shock ◽  
Radio Telemetry ◽  
Macula Densa ◽  
Pressure Recovery ◽  
Renin Release ◽  
Limiting Factor ◽  
Sodium Diet

Renin is a rate limiting factor for generation of angiotensin II, which is essential for blood pressure regulation. The role of macula densa nitric oxide (NO) in renin release is not conclusive. The goal of this study was to elucidate the role of macula densa neuronal NO synthase (NOS1) in control of renin release in response to sodium challenges and hemorrhagic shock, as well as in blood pressure recovery after hemorrhagic shock. C57BL/6L mice and macula densa specific NOS1 knockout (MD-NOS1KO) mice were given 10 days of low (0.1% NaCl), normal (0.4% NaCl) and high (1.4% NaCl) sodium diet. Hemorrhagic shock was induced by withdrawing 0.4 ml whole blood from the right retro-orbital sinus. Mean arterial pressure (MAP) in conscious mice was monitored by radio-telemetry system. Plasma renin concentration (PRC) was determined by radioimmunoassay. Low sodium diet stimulated PCR by 29% (from 685 ± 32 to 883 ± 112 ng/ml/hr) in WT mice and by 16% (from 652 ± 24 to 756 ± 124 ng/ml/hr) in the MD-NOS1KO mice (n=5/group, p<0.01 vs WT). PCR was not significantly different between the WT and MD-NOS1KO mice fed a normal or high salt diet. As shown in Fig1A, following removal of 0.4ml of blood, MAP dropped to about 40mmHg in the WT mice and 35mmHg in the MD-NOS1KO mice. MAP recovered faster in WT mice than the MD-NOS1KO mice. In Fig1B, PRC increased over 200% of the basal value in WT mice, but only increased about 26% in the MD-NOS1KO mice (n=4/group, p<0.01 vs WT). We conclude that NOS1 in the macula densa facilitates renin release. Lack of macula densa NO generation impairs blood pressure recovery, which may be mediated by limiting renin release during hemorrhagic shock.

Selective neuronal nitric oxide synthase inhibition blocks furosemide-stimulated renin secretion in vivo

1995 ◽  
Vol 269 (1) ◽  
pp. F134-F139 ◽  
Author(s):  
W. H. Beierwaltes
Keyword(s):  
Nitric Oxide ◽  
Blood Pressure ◽  
Nitric Oxide Synthase ◽  
Perfusion Pressure ◽  
Renal Perfusion ◽  
Macula Densa ◽  
Renin Secretion ◽  
Renal Perfusion Pressure ◽  
Neuronal Nos ◽  
Oxide Synthase

The macula densa is a regulatory site for renin. It contains exclusively the neuronal isoform of nitric oxide synthase (NOS), suggesting NO could stimulate renin secretion through the macula densa pathway. To test whether neuronal NOS mediates renin secretion, renin was stimulated by either the renal baroreceptor or the diuretic furosemide (acting through the macula densa pathway). Renin secretion rate (RSR) was measured in 12 Inactin-anesthetized rats at normal (104 +/- 3 mmHg) and reduced renal perfusion pressure (65 +/- 1 mmHg), before and after selective blockade of the neuronal NOS with 7-nitroindazole (7-NI, 50 mg/kg ip). 7-NI had no effect on basal blood pressure (102 +/- 2 mmHg) or renal blood flow (RBF). Decreasing renal perfusion pressure doubled RSR from 11.8 +/- 3.3 to 22.9 +/- 5.7 ng ANG I.h-1.min-1 (P < 0.01) (ANG I is angiotensin I). Similarly, in 7-NI-treated rats, reduced perfusion doubled RSR from 8.5 +/- 1.8 to 20.5 +/- 6.2 ng ANG I.h-1.min-1 (P < 0.01). Renal hemodynamics and RSR were measured in response to 5 mg/kg iv furosemide in 12 control rats and 11 rats treated with 7-NI. Blocking neuronal NOS did not alter blood pressure (102 +/- 2 mmHg), RBF (5.8 +/- 0.4 ml.min-1.g kidney wt-1), or renal vascular resistance (18.7 +/- 1.4 mmHg.ml-1.min.g kidney wt).(ABSTRACT TRUNCATED AT 250 WORDS)

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.

PHYSIOLOGIC AND MOLECULAR CHARACTERIZATION OF THE ROLE OF NITRIC OXIDE IN HEMORRHAGIC SHOCK

Shock ◽  
1997 ◽  
Vol 7 (3) ◽  
pp. 157-163 ◽  
Author(s):  
Edward Kelly ◽  
Nishit S. Shah ◽  
Nathan N. Morgan ◽  
Simon C. Watkins ◽  
Andrew B. Peitzman ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Hemorrhagic Shock ◽  
Molecular Characterization

scholarly journals Nitric oxide synthase-mediated blood pressure regulation in obese melanocortin-4 receptor-deficient pregnant rats

2016 ◽  
Vol 311 (5) ◽  
pp. R851-R857 ◽  
Author(s):  
Frank T. Spradley ◽  
Jennifer M. Sasser ◽  
Jacqueline B. Musall ◽  
Jennifer C. Sullivan ◽  
Joey P. Granger
Keyword(s):  
Nitric Oxide ◽  
Blood Pressure ◽  
Mesenteric Arteries ◽  
Elevated Blood Pressure ◽  
Pressure Regulation ◽  
Elevated Blood ◽  
Pregnant Rats ◽  
Melanocortin 4 Receptor ◽  
Regulation Of Blood Pressure

Although obesity increases the risk for hypertension in pregnancy, the mechanisms responsible are unknown. Increased nitric oxide (NO) production results in vasodilation and reduced blood pressure during normal pregnancy in lean rats; however, the role of NO is less clear during obese pregnancies. We examined the impact of obesity on NO synthase (NOS)-mediated regulation of blood pressure during pregnancy by testing the hypothesis that NOS activity, expression, and regulation of vascular tone and blood pressure are reduced in obese pregnant rats. At gestational day 19, melanocortin-4 receptor (MC4R)-deficient obese rats (MC4R) had greater body weight and fat mass with elevated blood pressure and circulating sFlt-1 levels compared with MC4R pregnant rats. MC4R pregnant rats also had less circulating cGMP levels and reduced total NOS enzymatic activity and expression in mesenteric arteries. Despite decreased biochemical measures of NO/NOS in MC4R rats, NOS inhibition enhanced vasoconstriction only in mesenteric arteries from MC4R rats, suggesting greater NOS-mediated tone. To examine the role of NOS on blood pressure regulation in obese pregnant rats, MC4R and MC4R pregnant rats were administered the nonselective NOS inhibitor NG-nitro-l-arginine methyl ester (l-NAME, 100 mg/l) from gestational day 14 to 19 in drinking water. The degree by which l-NAME raised blood pressure was similar between obese and lean pregnant rats. Although MC4R obese pregnant rats had elevated blood pressure associated with reduced total NOS activity and expression, they had enhanced NOS-mediated attenuation of vasoconstriction, with no evidence of alterations in NOS-mediated regulation of blood pressure.

scholarly journals Role of the endothelium-dependent relaxing factor nitric oxide on renal function.

1992 ◽  
Vol 2 (9) ◽  
pp. 1371-1387 ◽  
Author(s):  
J C Romero ◽  
V Lahera ◽  
M G Salom ◽  
M L Biondi
Keyword(s):  
Nitric Oxide ◽  
Renal Function ◽  
Perfusion Pressure ◽  
Sodium Intake ◽  
Systemic Circulation ◽  
Renal Perfusion ◽  
Renin Release ◽  
High Sodium ◽  
Renal Perfusion Pressure

The role of nitric oxide in renal function has been assessed with pharmacologic and physiologic interventions. Pharmacologically, the renal vasodilation and, to some extent, the natriuresis produced by endothelium-dependent vasodilators such as acetylcholine and bradykinin are mediated by nitric oxide and also by prostaglandins. However, prostaglandins and nitric oxide do not participate in the renal effects produced by endothelium-independent vasodilators such as atrial natriuretic peptide, prostaglandin I2, and nitroprusside. Physiologically, nitric oxide and prostaglandins exert a strong regulation on the effects produced by changes in renal perfusion pressure. Increments in renal perfusion pressure within the range of RBF autoregulation appear to inhibit prostaglandin synthesis while simultaneously enhancing the formation of nitric oxide. Nitric oxide modulates autoregulatory vasoconstriction and at the same time inhibits renin release. Conversely, a decrease of renal perfusion pressure to the limit of or below RBF autoregulation may inhibit the synthesis of nitric oxide but may trigger the release of prostaglandins, whose vasodilator action ameliorates the fall in RBF and stimulates renin release. Nitric oxide and prostaglandins are also largely responsible for mediating pressure-induced natriuresis. However, unlike prostaglandins, mild impairment of the synthesis of nitric oxide in systemic circulation produces a sustained decrease in sodium excretion, which renders blood pressure susceptible to be increased during high-sodium intake. This effect suggests that a deficiency in the synthesis of nitric oxide could constitute the most effective single disturbance to foster the development of a syndrome similar to that seen in salt-sensitive hypertension.

scholarly journals Role of nitric oxide in the control of blood pressure in salt-loaded Wistar rats.

1996 ◽  
Vol 71 ◽  
pp. 320
Author(s):  
Norikazu Yamaguchi ◽  
Takeshi Fujii ◽  
Kazuko Fujimoto ◽  
Takeshi Suzuki ◽  
Koichiro Kawashima
Keyword(s):  
Nitric Oxide ◽  
Blood Pressure ◽  
Wistar Rats

scholarly journals Chronic Endothelium-Dependent Regulation of Arterial Blood Pressure by Atrial Natriuretic Peptide: Role of Nitric Oxide and Endothelin-1

Endocrinology ◽  
2009 ◽  
Vol 150 (5) ◽  
pp. 2382-2387 ◽  
Author(s):  
Karim Sabrane ◽  
Markus-N. Kruse ◽  
Alexandra Gazinski ◽  
Michaela Kuhn
Keyword(s):  
Nitric Oxide ◽  
Blood Pressure ◽  
Methyl Ester ◽  
Atrial Natriuretic Peptide ◽  
Arterial Blood Pressure ◽  
Natriuretic Peptide ◽  
Endothelin 1 ◽  
Arterial Blood ◽  
Atrial Natriuretic

Atrial natriuretic peptide (ANP), via its guanylyl cyclase (GC)-A receptor, plays a key role in the regulation of arterial blood pressure (ABP) and volume. Endothelial-restricted deletion of GC-A in mice [endothelial cell (EC) GC-A knockout (KO)] resulted in hypervolemic hypertension, demonstrating that the endothelium participates in the hypotensive and hypovolemic actions of ANP. Published studies showed that ANP modulates the release of the vasoactive factors nitric oxide (NO) and endothelin-1 (ET-1) from cultured endothelia. Based on these observations, we examined the role of these endothelial factors in ANP-dependent vasodilatation (studied in isolated arteries) and chronic regulation of ABP (measured in awake mice by tail-cuff plethysmography). ANP induced concentration-dependent vasorelaxations of aortic, carotid, and pulmonary arteries. These responses were not different between control and EC GC-A KO mice, and were significantly enhanced after inhibition of NO synthase [by N(G)-nitro-l-arginine-methyl ester]. Intravenous administration of N(G)-nitro-l-arginine-methyl ester to conscious mice significantly increased ABP. The extent of these hypertensive reactions was similar in EC GC-A KO mice and control littermates (increases in systolic blood pressure by ∼25 mm Hg). Conversely, antagonism of ET-1/endothelin-A receptors with BQ-123 reduced ABP significantly and comparably in both genotypes (by ∼11 mm Hg). Finally, the vascular and tissue expression levels of components of the NO system and of immunoreactive ET-1 were not different in control and EC GC-A KO mice. We conclude that the endothelium, but not modulation of endothelial NO or ET-1, participates in the chronic regulation of ABP by ANP.

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