Nitric oxide and prostaglandins are involved in the macula densa control of the renin system

1995 ◽  
Vol 269 (6) ◽  
pp. F825-F830 ◽  
Author(s):  
K. Schricker ◽  
M. Hamann ◽  
A. Kurtz
Keyword(s):  
Nitric Oxide ◽  
Plasma Renin ◽  
Macula Densa ◽  
Salt Transport ◽  
Mrna Levels ◽  
Sprague Dawley ◽  
No Formation ◽  
Sprague Dawley Rats ◽  
Renin Mrna

This study sought to examine the involvement of prostaglandins and of nitric oxide (NO) in the macula densa-dependent activation of the renin system in vivo. For this purpose, male Sprague-Dawley rats were chronically infused with furosemide (12 mg/day) for 6 days to inhibit macula densa salt transport. To inhibit the synthesis of prostaglandins and of NO, animals were injected with indomethacin (2 mg/kg twice daily) and with nitro-L-arginine methyl ester (L-NAME; 40 mg/kg twice daily) for the last 2 days of the experiment, respectively. Furosemide infusion increased plasma renin activity (PRA) from 8.8 +/- 1.4 to 41 +/- 5.2 ng angiotensin I (ANG I).h-1.ml-1 and renin mRNA levels from 112 +/- 8 of standard to 249 +/- 18% of standard. After treatment with indomethacin, the furosemide-induced increases in renin mRNA levels was attenuated to 190 +/- 11% of standard. After injections of L-NAME, both the furosemide-induced increases of renin mRNA levels and of PRA were reduced to 126 +/- 14% of standard and 22 +/- 5 ng ANG I.h-1.ml-1, respectively. These findings suggest that activation of renin gene expression by blockade of the macula densa function is dependent on intact NO and prostaglandin formation, whereas for stimulation of renin secretion mainly intact NO formation appears to be necessary.

Acute hypoxia stimulates renin secretion and renin gene expression in vivo but not in vitro

1997 ◽  
Vol 272 (4) ◽  
pp. R1105-R1111 ◽  
Author(s):  
T. Ritthaler ◽  
K. Schricker ◽  
F. Kees ◽  
B. Kramer ◽  
A. Kurtz
Keyword(s):  
Gene Expression ◽  
Acute Hypoxia ◽  
Primary Cultures ◽  
Renin Secretion ◽  
Plasma Norepinephrine ◽  
Mrna Levels ◽  
Sprague Dawley ◽  
Renin Gene ◽  
Renin Mrna

This study aimed at examining the influence of acute hypoxia on renin secretion and renin gene expression in the kidney. To this end, male Sprague-Dawley rats were exposed to severe hypoxic stress (8% O2) or to carbon monoxide (0.1% CO) for 6 h, and plasma renin activity (PRA) and renal renin mRNA levels were determined. PRA values increased from 3 to 13 and 10 ng angiotensin I x h(-1) x ml(-1), and renin mRNA levels increased by 120 and 100% during hypoxia and CO, respectively. Lowering the PO2 from 150 to 20 or 7 mmHg in the gas atmosphere of primary cultures of renal juxtaglomerular cells had no influence on renin secretion and renin gene expression after 6 and 20 h. Our findings thus suggest that both arterial and venous hypoxia can be powerful stimulators of renin secretion and renin gene expression in vivo. Because renal denervation did not prevent stimulation of the renin system by hypoxia, the effect could be indirectly mediated via the baroreceptor-macula densa mechanism. Another potential mediator of the effect could be circulating catecholamines, since we found that plasma norepinephrine increased from 0.7 to 1.5 and 2.4 ng/ml and plasma epinephrine increased from 0.3 to 1.4 and 2.7 ng/ml during hypoxia and CO inhalation, respectively.

Preserved macula densa-dependent renin secretion in A1 adenosine receptor knockout mice

2003 ◽  
Vol 284 (4) ◽  
pp. F770-F777 ◽  
Author(s):  
Frank Schweda ◽  
Charlotte Wagner ◽  
Bernhard K. Krämer ◽  
Jürgen Schnermann ◽  
Armin Kurtz
Keyword(s):  
Mrna Expression ◽  
Glomerular Filtration ◽  
Knockout Mice ◽  
Macula Densa ◽  
Salt Transport ◽  
Renin Secretion ◽  
Renin Mrna ◽  
Renin Content

Recent studies demonstrated that the influence of the macula densa on glomerular filtration is abolished in adenosine A1 receptor (A1AR) knockout mice. Inasmuch as the macula densa not only regulates glomerular filtration but also controls the activity of the renin system, the present study aimed to determine the role of the A1AR in macula densa control of renin synthesis and secretion. Although a high-salt diet over 1 wk suppressed renin mRNA expression and renal renin content to similar degrees in A1AR+/+, A1AR+/−, and A1AR−/−mice, stimulation of Ren-1 mRNA expression and renal renin content by salt restriction was markedly enhanced in A1AR−/− compared with wild-type mice. Pharmacological blockade of macula densa salt transport with loop diuretics stimulated renin expression in vivo (treatment with furosemide at 1.2 mg/day for 6 days) and renin secretion in isolated perfused mouse kidneys (treatment with 100 μM bumetanide) in all three genotypes to the same extent. Taken together, our data are consistent with the concept of a tonic inhibitory role of the A1AR in the renin system, whereas they indicate that the A1AR is not indispensable in macula densa control of the renin system.

Inhibition of matrix metalloproteinase activity in vivo protects against vascular hyporeactivity in endotoxemia

2010 ◽  
Vol 298 (1) ◽  
pp. H45-H51 ◽  
Author(s):  
Jonathan J. Cena ◽  
Manoj M. Lalu ◽  
Woo Jung Cho ◽  
Ava K. Chow ◽  
Mariel L. Bagdan ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Ex Vivo ◽  
Free Water ◽  
Gelatin Zymography ◽  
Sprague Dawley ◽  
Mmp Inhibitor ◽  
Sprague Dawley Rats ◽  
Vascular Hyporeactivity ◽  
Oxide Synthase

Persistent arterial hypotension is a hallmark of sepsis and is believed to be caused, at least in part, by excess nitric oxide (NO). NO can combine with superoxide to produce peroxynitrite, which activates matrix metalloproteinases (MMPs). Whether MMP inhibition in vivo protects against vascular hyporeactivity induced by endotoxemia is unknown. Male Sprague-Dawley rats were administered either bacterial lipopolysaccharide (LPS, 4 mg/kg ip) or vehicle (pyrogen-free water). Later (30 min), animals received the MMP inhibitor doxycycline (4 mg/kg ip) or vehicle (pyrogen-free water). After LPS injection (6 h), animals were killed, and aortas were excised. Aortic rings were mounted in organ baths, and contractile responses to phenylephrine or KCl were measured. Aortas and plasma were examined for MMP activity by gelatin zymography. Aortic MMP and inducible nitric oxide synthase (iNOS) were examined by immunoblot and/or immunohistochemistry. Doxycycline prevented the LPS-induced development of ex vivo vascular hyporeactivity to phenylephrine and KCl. iNOS protein was significantly upregulated in aortic homogenates from endotoxemic rats; doxycycline did not alter its level. MMP-9 activity was undetectable in aortic homogenates from LPS-treated rats but significantly upregulated in the plasma; this was attenuated by doxycycline. Plasma MMP-2 activities were unchanged by LPS. Specific MMP-2 activity was increased in aortas from LPS-treated rats. This study demonstrates the in vivo protective effect of the MMP inhibitor doxycycline against the development of vascular hyporeactivity in endotoxemic rats.

scholarly journals Nitric oxide release as an essential mitigating step in tubuloglomerular feedback: observations during intrarenal nitric oxide clamp.

1998 ◽  
Vol 9 (9) ◽  
pp. 1596-1603
Author(s):  
E Turkstra ◽  
B Braam ◽  
H A Koomans
Keyword(s):  
Nitric Oxide ◽  
Macula Densa ◽  
Tubuloglomerular Feedback ◽  
Sprague Dawley ◽  
Arginine Infusion ◽  
Nitric Oxide Release ◽  
Sprague Dawley Rats ◽  
Flow Pressure ◽  
Oxide Synthase ◽  
Nitroprusside Infusion

Nitric oxide synthase inhibition in the kidney enhances tubuloglomerular feedback (TGF) responsiveness. This may reflect either the effect of reduced basal nitric oxide (NO) availability or the effect of impaired NO release that is physiologically induced by TGF activation. However, it is unknown whether the latter actually takes place. In this study, it was hypothesized that NO is released (from macula densa cells or endothelium) as part of the normal TGF loop, and mitigates the TGF response. In Sprague Dawley rats, TGF responsiveness was assessed (fall in tubular stop flow pressure, deltaSFP, upon switching loop of Henle perfusion rates from 0 to 40 nl/min) during an intrarenal NO clamp (systemic infusion of nitro-L-arginine, 10 microg/kg per min, followed by intrarenal nitroprusside infusion adjusted to restore renal blood flow [RBF]). This maneuver was presumed to fix intrarenal NO impact at a physiologic level. To validate the approach, TGF responsiveness during an intrarenal angiotensin II (AngII) clamp (systemic infusion of enalaprilat 0.2 mg/kg per min, followed by intrarenal AngII infusion) was also studied. AngII is presumed to modulate but not mediate, TGF, thus not to increase as part of the TGF loop. In untreated animals, RBF was 7.4 +/- 0.4 ml/min, and deltaSFP was 5.7 +/- 1.6 mmHg. Nitro-L-arginine infusion alone reduced RBF to 5.3 +/- 0.5 ml/min (P < 0.05); with nitroprusside infusion, RBF was restored to 8.3 +/- 0.7 ml/min. In this condition (NO clamp), deltaSFP was markedly increased to 19.6 +/- 3.2 mmHg (P < 0.05). By contrast, deltaSFP, which was virtually abolished during enalaprilat alone (0.2 +/- 0.3 mmHg), was not significantly different from controls during AngII clamp (8.2 +/- 1.0 mmHg). These data suggest that NO may well be released upon TGF activation. By contrast, AngII is not dynamically involved in TGF activation, but may modulate the TGF response. Thus, dynamic release of NO during TGF activation mitigates the TGF response, so that it will offset the action of a primary, as yet undefined, vasoconstrictor mediator. The source of this NO, macula densa or endothelium, remains to be elucidated.

Selective A1 adenosine receptor antagonism augments beta-adrenergic-induced renin release in vivo

1995 ◽  
Vol 269 (4) ◽  
pp. F469-F479 ◽  
Author(s):  
C. A. Pfeifer ◽  
F. Suzuki ◽  
E. K. Jackson
Keyword(s):  
Plasma Renin ◽  
Renin Release ◽  
Control Group ◽  
Sprague Dawley ◽  
Endogenous Adenosine ◽  
Adenosine A2 Receptor ◽  
Sprague Dawley Rats ◽  
Receptor Interactions ◽  
A1 Receptor

This study determines, in vivo, whether endogenous adenosine/A1 receptor interactions at juxtaglomerular cells restrain the release of renin induced by receptor-mediated activation of the adenosine 3',5'–cyclic monophosphate pathway and whether endogenous adenosine/A2 receptor interactions diminish this restraining response. The following four pharmacological probes were employed: 1) 1,3-dipropyl-8-cyclopentylxanthine (DPCPX) and 2) FK-453, both selective A1 receptor antagonists; 3) FR-113452, a nearly inactive enantiomer of FK-453; and 4) KF-17837, a selective A2 receptor blocker. Adult Sprague-Dawley rats were prepared (adrenalectomized, renal denervated, uninephrectomized, and treated with indomethacin, aldosterone, and hydrocortisone) to minimize endogenous stimulation of renin release and received either vehicle (control group) or one of the four drugs. Intrarenal infusions of isoproterenol (3, 30, and 100 ng.kg-1.min-1) caused dose-related increases in plasma renin activity (PRA). This PRA response was significantly augmented in the groups receiving DPCPX (P = 0.0010) or FK-453 (P = 0.0001) but was not altered in the groups treated with FR-113452 (P = 0.3422) or KF-17837 (P = 0.2155). Systemic and renal hemodynamics and renal electrolyte excretions were monitored and could not account for the PRA augmentation caused by the A1 antagonists. This study clearly demonstrates that endogenous adenosine acts on the A1 receptor to restrain the renin release induced by activation of intrarenal beta-adrenoceptors and is not counteracted by endogenous activation of the A2 receptor.

Acute hypoxia upregulates NOS gene expression in rats

1997 ◽  
Vol 273 (3) ◽  
pp. R905-R910 ◽  
Author(s):  
B. Gess ◽  
K. Schricker ◽  
M. Pfeifer ◽  
A. Kurtz
Keyword(s):  
Gene Expression ◽  
Carbon Monoxide ◽  
Acute Hypoxia ◽  
Mrna Levels ◽  
General Effect ◽  
Sprague Dawley ◽  
Sprague Dawley Rats ◽  
Flow Through ◽  
Ribonuclease Protection

This study aimed to investigate the influence of acute tissue hypoxygenation on the expression of NO synthase (NOS) genes in vivo. To this end, male Sprague-Dawley rats were exposed either to 9% oxygen or to 0.1% carbon monoxide for 6 h, and mRNA levels of NOS-I, -II, and -III in kidneys, livers, lungs, and left and right heart ventricles were assayed by ribonuclease protection. For comparison, mRNA levels of erythropoietin were also measured in these tissues. NOS-III mRNA was highly abundant in all organs investigated. NOS-II mRNA was detected in lungs and hearts but not in kidneys and livers. NOS-I mRNA was found in kidneys, lungs, and hearts but not in livers. NOS-III mRNA levels were upregulated by hypoxia in all tissues examined, with the least effect (1.2-fold) in the left ventricle and the greatest effect (2.6-fold) in the lung. NOS-II mRNA was substantially downregulated in the ventricles by both treatments but not changed in the lung. NOS-I mRNA was upregulated by carbon monoxide in kidneys and lungs and by 9% oxygen in the lung. These findings suggest that NOS-III and possibly also NOS-I gene expression behave like oxygen-regulated genes, whereas the general effect of tissue hypoxygenation on NOS-II gene expression is less clear. Because NOS-III is primarily expressed in endothelial cells, a general upregulation of NOS in these cells may be of relevance for the regulation and maintenance of blood flow through hypoxic tissues.

17β-Estradiol increases nitric oxide-dependent dilation in rat pulmonary arteries and thoracic aorta

2001 ◽  
Vol 280 (3) ◽  
pp. L555-L564 ◽  
Author(s):  
Rayna J. Gonzales ◽  
Benjimen R. Walker ◽  
Nancy L. Kanagy
Keyword(s):  
Nitric Oxide ◽  
Rnase Protection Assay ◽  
Pulmonary Arteries ◽  
Treated Group ◽  
Pulmonary Vasculature ◽  
Mrna Levels ◽  
Sprague Dawley ◽  
Rnase Protection ◽  
17Β Estradiol

Past studies have demonstrated that 17β-estradiol (E2β) increases endothelial nitric oxide (NO) synthase (eNOS) activity in uterine, heart, and skeletal muscle and in cultured human endothelial cells. However, little is known about E2β regulation of NO synthesis in the pulmonary vasculature. The present study evaluated E2β regulation of eNOS function in pulmonary arteries and thoracic aortas. We hypothesized that E2β upregulates vascular NO release by increasing eNOS expression. To test this, NO-dependent vasodilation was assessed in isolated perfused lungs and aortic rings from ovariectomized Sprague-Dawley rats treated for 1 wk with 20 μg/24 h of E2β or vehicle. Expression of eNOS was evaluated by Western blot and immunohistochemistry. Also, a RNase protection assay determined eNOS mRNA levels in lung and aortic homogenates from control and treated rats. Vasodilation to ionomycin in lungs from the E2β-treated group was enhanced compared with that in control animals. Endothelium-intact aortic rings from E2β-treated animals also demonstrated augmented endothelium-dependent dilation. Both responses were blocked with NOS inhibition. Immunostaining for eNOS was greater in pulmonary arteries and aortas from E2β-treated compared with control rats. However, mRNA levels did not differ between groups. Thus we conclude that in vivo E2β treatment augments endothelium-dependent dilation in aorta and lung, increasing expression of eNOS independently of sustained augmented gene transcription.

Glutamate induces hydroxyl radical formation in vivo via activation of nitric oxide synthase in Sprague–Dawley rats

1998 ◽  
Vol 242 (3) ◽  
pp. 131-134 ◽  
Author(s):  
Eric Lancelot ◽  
Laurent Lecanu ◽  
Marie-Louise Revaud ◽  
Roger G Boulu ◽  
Michel Plotkine ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Nitric Oxide Synthase ◽  
Hydroxyl Radical ◽  
Radical Formation ◽  
Sprague Dawley ◽  
Sprague Dawley Rats ◽  
Oxide Synthase

Distribution and content of renin and renin mRNA in remnant kidney of adult rat

1992 ◽  
Vol 263 (4) ◽  
pp. F731-F738 ◽  
Author(s):  
C. Pupilli ◽  
R. L. Chevalier ◽  
R. M. Carey ◽  
R. A. Gomez
Keyword(s):  
Left Kidney ◽  
Weight Ratio ◽  
Plasma Renin ◽  
Sham Operation ◽  
Sprague Dawley ◽  
Dot Blot ◽  
Adult Rat ◽  
Sprague Dawley Rats ◽  
Renin Mrna ◽  
Dot Blot Assay

To determine whether kidney hypertrophy secondary to reduction of renal mass affects the intrarenal distribution and concentration of renin mRNA and its protein, adult male Sprague-Dawley rats were studied 4 wk after sham operation (Sham, n = 10), uninephrectomy (UNX, n = 14), or five-sixths nephrectomy (5/6 NX, n = 12). Left kidney weight-to-body weight ratio (x10(3)) was higher in 5/6 NX (6.6 +/- 0.2) than in UNX (4.5 +/- 0.2) or Sham (3.8 +/- 0.1) groups (P < 0.001). The percentage of juxtaglomerular apparatuses (%JGA) containing renin was lower in 5/6 NX (32 +/- 5) than in UNX (56 +/- 2, P < 0.001) or Sham (50 +/- 1, P < 0.05) groups. Renal renin mRNA concentrations (pg renin mRNA/microgram total RNA) detected by radiodensitometric renin mRNA dot-blot assay were lower in 5/6 NX (1.8 +/- 0.3) than in UNX (13.2 +/- 1) or Sham (14.2 +/- 1.1, P < 0.001). In situ hybridization histochemistry demonstrated that in all groups of rats renin mRNA was confined to the JGA. However, the hybridization signals (grains/JGA) were less intense in 5/6 NX (211 +/- 24) than in UNX (486 +/- 35) or Sham (541 +/- 40) groups (P < 0.001). Renal renin concentration (ng angiotensin I.mg protein-1.h-1) tended to be lower in 5/6 NX (20 +/- 15) than in UNX (44 +/- 7.8) or Sham (60.8 +/- 10) groups. In addition, plasma renin activity (ng.ml-1.h-1) was lower in 5/6 NX (3.8 +/- 0.6) than in UNX (8.8 +/- 1.8, P < 0.05) or Sham (14.3 +/- 2, P < 0.001) groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Role of neuronal nitric oxide in methamphetamine neurotoxicity and protection by nNOS inhibitor

2000 ◽  
Vol 72 (6) ◽  
pp. 1001-1006 ◽  
Author(s):  
D. Desaiah ◽  
S. L. N. Reddy ◽  
S. Z. Imam ◽  
S. F. Ali
Keyword(s):  
Nitric Oxide ◽  
Brain Regions ◽  
Selective Inhibitor ◽  
Sprague Dawley ◽  
Catecholaminergic System ◽  
Sprague Dawley Rats ◽  
Oxide Synthase ◽  
The Brain

Methamphetamine (METH) is a potent psychostimulant known to produce neurotoxicity. The dopaminergic pathway is particularly sensitive to METH. Recent studies showed that 7-nitroindazole (7-NI), a selective inhibitor of neuronal nitric oxide synthase (nNOS), provided protection against METH neurotoxicity both in vitro and in vivo. The present studies were conducted to determine the nNOS activity in various regions of the brain of young adult male Sprague-Dawley rats treated with different doses of METH. Rats were injected ip with 5, 10, 20, and 40 mg/kg and 24 h after the rats were sacrificed and the brain regions (hippocampus, frontal cortex, and cerebellum) were quickly dissected. The cytosolic fractions were prepared, and the nNOS activity was determined using the 3H-citrulline assay. The results showed that nNOS activity was significantly increased in all three brain regions of rats treated with METH. The increase was dose dependent reaching a maximum of 40-100% over the control values. Rats treated with 7NI 30 min prior to METH injection provided protection against the toxicity and also showed a reduction of nNOS activity. The activation of nNOS is known to increase the synthesis of NO which is involved in the regulation of several neurotransmitter pathways including catecholaminergic system. Reducing the METH-induced production of NO by pretreatment with selective inhibitor of nNOS, 7-NI, provided protection against METH neurotoxicity.

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