Mechanisms of flow and ACh-induced dilation in rat soleus arterioles are altered by hindlimb unweighting

2002 ◽  
Vol 92 (3) ◽  
pp. 901-911 ◽  
Author(s):  
William G. Schrage ◽  
Christopher R. Woodman ◽  
M. Harold Laughlin
Keyword(s):  
Weight Bearing ◽  
Combined Treatment ◽  
Sprague Dawley ◽  
Hindlimb Unweighting ◽  
First Order ◽  
Sprague Dawley Rats ◽  
Independent Mechanism ◽  
Rat Soleus Muscle ◽  
Luminal Flow ◽  
Oxide Synthase

The purpose of this study was to test the hypothesis that endothelium-dependent dilation (flow-induced dilation and ACh-induced dilation) in rat soleus muscle arterioles is impaired by hindlimb unweighting (HLU). Male Sprague-Dawley rats (∼300 g) were exposed to HLU or weight-bearing control (Con) conditions for 14 days. Soleus first-order (1A) and second-order (2A) arterioles were isolated, cannulated, and exposed to step increases in luminal flow at constant pressure. Flow-induced dilation was not impaired by HLU in 1A or 2A arterioles. The cyclooxygenase inhibitor indomethacin (Indo; 50 μM) did not alter flow-induced dilation in 1As or 2As. Inhibition of nitric oxide synthase (NOS) with N ω-nitro-l-arginine (l-NNA; 300 μM) reduced flow-induced dilation by 65–70% in Con and HLU 1As. In contrast, l-NNA abolished flow-induced dilation in 2As from Con rats but had no effect in HLU 2As. Combined treatment with l-NNA + Indo reduced tone in 1As and 2As from Con rats, but flow-induced dilation in the presence of l-NNA + Indo was not different from responses without inhibitors in either Con or HLU 1As or 2As. HLU also did not impair ACh-induced dilation (10−9-10−4 M) in soleus 2As.l-NNA reduced ACh-induced dilation by ∼40% in Con 2As but abolished dilation in HLU 2As. Indo did not alter ACh-induced dilation in Con or HLU 2As, whereas combined treatment withl-NNA + Indo abolished ACh-induced dilation in 2As from both groups. We conclude that flow-induced dilation (1As and 2As) was preserved after 2 wk HLU, but HLU decreased the contribution of NOS in mediating flow-induced dilation and increased the contribution of a NOS- and cyclooxygenase-independent mechanism (possibly endothelium-derived hyperpolarizing factor). In soleus 2As, ACh-induced dilation was preserved after 2-wk HLU but the contribution of NOS in mediating ACh-induced dilation was increased.

AMPK stimulation increases LCFA but not glucose clearance in cardiac muscle in vivo

2004 ◽  
Vol 287 (5) ◽  
pp. E871-E877 ◽  
Author(s):  
Jane Shearer ◽  
Patrick T. Fueger ◽  
Jeffrey N. Rottman ◽  
Deanna P. Bracy ◽  
Paul H. Martin ◽  
...  
Keyword(s):  
Cardiac Muscle ◽  
Sprague Dawley ◽  
Long Chain Fatty Acid ◽  
Sprague Dawley Rats ◽  
Glucose Clearance ◽  
Independent Mechanism ◽  
Amp Activated Protein Kinase ◽  
Oxide Synthase ◽  
Lcfa Uptake

AMP-activated protein kinase (AMPK) independently increases glucose and long-chain fatty acid (LCFA) utilization in isolated cardiac muscle preparations. Recent studies indicate this may be due to AMPK-induced phosphorylation and activation of nitric oxide synthase (NOS). Given this, the aim of the present study was to assess the effects of AMPK stimulation by 5-aminoimidazole-4-carboxamide-1-β-d-ribofuranoside (AICAR; 10 mg·kg−1·min−1) on glucose and LCFA utilization in cardiac muscle and to determine the NOS dependence of any observed effects. Catheters were chronically implanted in a carotid artery and jugular vein of Sprague-Dawley rats. After 4 days of recovery, conscious, unrestrained rats were given either water or water containing 1 mg/ml nitro-l-arginine methyl ester (l-NAME) for 2.5 days. After an overnight fast, rats underwent one of four protocols: saline, AICAR, AICAR + l-NAME, or AICAR + Intralipid (20%, 0.02 ml·kg−1·min−1). Glucose was clamped at ∼6.5 mM in all groups, and an intravenous bolus of 2-deoxy-[3H]glucose and [125I]-15-( p-iodophenyl)-3- R, S-methylpentadecanoic acid was administered to obtain indexes of glucose and LCFA uptake and clearance. Despite AMPK activation, as evidenced by acetyl-CoA carboxylase (Ser221) and AMPK phosphorylation (Thr172), AICAR increased cardiac LCFA but not glucose clearance. l-NAME + AICAR established that this effect was not due to NOS activation, and AICAR + Intralipid showed that increased cardiac LCFA clearance was not LCFA-concentration dependent. These results demonstrate that, in vivo, AMPK stimulation increases LCFA but not glucose clearance by a NOS-independent mechanism.

Hindlimb unweighting decreases ecNOS gene expression and endothelium-dependent dilation in rat soleus feed arteries

1999 ◽  
Vol 87 (4) ◽  
pp. 1476-1482 ◽  
Author(s):  
Jeffrey L. Jasperse ◽  
Christopher R. Woodman ◽  
Elmer M. Price ◽  
Eileen M. Hasser ◽  
M. Harold Laughlin
Keyword(s):  
Blood Flow ◽  
Protein Expression ◽  
Muscle Blood Flow ◽  
Sprague Dawley ◽  
Hindlimb Unweighting ◽  
Sprague Dawley Rats ◽  
Reduced Physical Activity ◽  
Mrna And Protein Expression ◽  
Oxide Synthase ◽  
Feed Arteries

We tested the hypothesis that hindlimb unweighting (HLU) and the associated reduction in soleus muscle blood flow causes decreased expression of endothelial cell nitric oxide synthase (ecNOS) mRNA and protein and attenuated endothelium-dependent vasodilator responses in rat soleus feed arteries (SFA). Male Sprague-Dawley rats were exposed to HLU ( n = 12) or cage control (Con; n = 12) conditions for 14 days. At the end of this period, SFA were isolated, removed, and cannulated with two glass micropipettes for examination of vasodilator responses or frozen for analysis of ecNOS mRNA and protein expression. RT-PCR of RNA from single SFA was used to measure ecNOS mRNA, and immunoblots on single SFAs were used to measure ecNOS protein content. Results revealed that both ecNOS mRNA and ecNOS protein expression were lower in SFA from HLU rats. Dilation to increased intraluminal flow was attenuated in SFA from HLU rats (Con: 88 ± 8% vs. HLU: 53 ± 8%) as was maximal vasodilation to acetylcholine (10−9-10−4M; Con: 88 ± 5% vs. HLU: 73 ± 5%). Sensitivity to the endothelium-independent vasodilator sodium nitroprusside (10−10-10−4M) was enhanced by HLU (EC50: Con: 4.46 × 10−7 M vs. HLU: 5.00 × 10−8 M). Collectively, these data indicate that the chronic reduction in soleus blood flow associated with the reduced physical activity during HLU results in reduced expression of ecNOS mRNA and protein in SFA and attenuated endothelium-dependent vasodilation.

Differential sympathetic nerve responses to nitric oxide synthase inhibition in anesthetized rats

1995 ◽  
Vol 269 (4) ◽  
pp. R807-R813 ◽  
Author(s):  
T. Hirai ◽  
T. I. Musch ◽  
D. A. Morgan ◽  
K. C. Kregel ◽  
D. E. Claassen ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Sympathetic Nerve ◽  
Sprague Dawley ◽  
Arterial Blood ◽  
Sprague Dawley Rats ◽  
Before And After ◽  
Important Means ◽  
Nos Inhibitor ◽  
Oxide Synthase ◽  
Tonic Excitation

Recent studies have suggested that the interaction between the sympathetic nervous system and nitric oxide (NO) or nitrosyl factors may be an important means by which arterial blood pressure is regulated. We investigated whether NO synthase (NOS) inhibition modulates basal sympathetic nerve discharge (SND) in baroreceptor-innervated and -denervated, chloralose-anesthetized Sprague-Dawley rats. We recorded mean arterial pressure (MAP), renal SND, and lumbar SND before and after administration of the NOS inhibitor, NG-nitro-L-arginine methyl ester (L-NAME, 20 mg/kg iv). Two minutes after L-NAME administration in baroreceptor-innervated rats, MAP increased (+23 +/- 3 mmHg), whereas renal (-45 +/- 6%, n = 7) and lumbar (-35 +/- 2%, n = 6) SND significantly decreased from control levels. These changes persisted for up to 20 min after L-NAME administration. In baroreceptor-denervated rats, L-NAME increased MAP (+40 +/- 6 mmHg) and decreased lumbar SND (n = 7) (-37 +/- 10% from control at 20 min post-L-NAME). In contrast, renal SND progressively increased (+33 +/- 8% at 20 min post-L-NAME) from control after L-NAME administration in baroreceptor-denervated rats (n = 7). These results demonstrate that NOS inhibition can produce nonuniform changes in SND in baroreceptor-denervated rats and suggest that endogenous nitrosyl factors provide tonic excitation to lumbar SND, whereas they provide a tonic restraint to renal SND.

scholarly journals Hypertensive female Sprague-Dawley rats require an intact nitric oxide synthase system for compensatory increases in renal regulatory T cells

2020 ◽  
Vol 319 (2) ◽  
pp. F192-F201
Author(s):  
Lindsey A. Ramirez ◽  
Ellen E. Gillis ◽  
Jacqueline B. Musall ◽  
Riyaz Mohamed ◽  
Elizabeth Snyder ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
T Cells ◽  
Angiotensin Ii ◽  
Nitric Oxide Synthase ◽  
Regulatory T Cells ◽  
Female Rats ◽  
Sprague Dawley ◽  
Albumin Excretion ◽  
Sprague Dawley Rats ◽  
Oxide Synthase

We have previously shown that hypertensive female rats have more regulatory T cells (Tregs), which contribute more to blood pressure (BP) control in female versus male rats. Based on known protective properties of Tregs, the goal of the present study was to investigate the mechanisms by which female rats maintain Tregs. The present study was designed to 1) compare the impact of three hypertension models on the percentage of renal Tregs and 2) test the hypothesis that nitric oxide synthase (NOS) inhibition prevents increases in renal Tregs and exacerbates renal damage in female Sprague-Dawley rats. Rats (11–14 wk old) were randomized to one of the following four groups: control, norepinephrine (NE) infusion, angiotensin II infusion, or the NOS inhibitor Nω-nitro-l-arginine methyl ester (l-NAME) in drinking water. BP was measured via tail cuff. After 2 wk of treatment, kidneys were isolated and processed to measure Tregs via flow cytometric analysis and renal injury via urinary albumin excretion, plasma creatinine, and histological analyses. Hypertensive treatments increased BP in all experimental animals. Increases in BP in norepinephrine-and angiotensin II-treated rats were associated with increases in renal Tregs versus control. In contrast, l-NAME treatment decreased Tregs compared with all groups. l-NAME treatment modestly increased albumin excretion. However, plasma creatinine was comparable among the groups, and there was no histological evidence of glomerular or tubular injury. This study provides insights into the mechanisms regulating renal Tregs and supports that an intact NOS system is crucial for female rats to have BP-related increases in renal Tregs.

Nitric oxide modulation of glutamatergic, baroreflex, and cardiopulmonary transmission in the nucleus of the solitary tract

2005 ◽  
Vol 288 (1) ◽  
pp. H256-H262 ◽  
Author(s):  
Ana Carolina Rodrigues Dias ◽  
Melissa Vitela ◽  
Eduardo Colombari ◽  
Steven W. Mifflin
Keyword(s):  
Nitric Oxide ◽  
Solitary Tract ◽  
Glutamatergic Transmission ◽  
Sprague Dawley ◽  
Renal Sympathetic Nerve Activity ◽  
Sprague Dawley Rats ◽  
Before And After ◽  
Nos Inhibitor ◽  
The Right ◽  
Oxide Synthase

The neuromodulatory effect of NO on glutamatergic transmission has been studied in several brain areas. Our previous single-cell studies suggested that NO facilitates glutamatergic transmission in the nucleus of the solitary tract (NTS). In this study, we examined the effect of the nitric oxide synthase (NOS) inhibitor NG-nitro-l-arginine methyl ester (l-NAME) on glutamatergic and reflex transmission in the NTS. We measured mean arterial pressure (MAP), heart rate (HR), and renal sympathetic nerve activity (RSNA) from Inactin-anesthetized Sprague-Dawley rats. Bilateral microinjections of l-NAME (10 nmol/100 nl) into the NTS did not cause significant changes in basal MAP, HR, or RSNA. Unilateral microinjection of ( RS)-α-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA, 1 pmol/100 nl) into the NTS decreased MAP and RSNA. Fifteen minutes after l-NAME microinjections, AMPA-evoked cardiovascular changes were significantly reduced. N-methyl-d-aspartate (NMDA, 0.5 pmol/100 nl) microinjection into the NTS decreased MAP, HR, and RSNA. NMDA-evoked falls in MAP, HR, and RSNA were significantly reduced 30 min after l-NAME. To examine baroreceptor and cardiopulmonary reflex function, l-NAME was microinjected at multiple sites within the rostro-caudal extent of the NTS. Baroreflex function was tested with phenylephrine (PE, 25 μg iv) before and after l-NAME. Five minutes after l-NAME the decrease in RSNA caused by PE was significantly reduced. To examine cardiopulmonary reflex function, phenylbiguanide (PBG, 8 μg/kg) was injected into the right atrium. PBG-evoked hypotension, bradycardia, and RSNA reduction were significantly attenuated 5 min after l-NAME. Our results indicate that inhibition of NOS within the NTS attenuates baro- and cardiopulmonary reflexes, suggesting that NO plays a physiologically significant neuromodulatory role in cardiovascular regulation.

Carbon monoxide promotes endothelium-dependent constriction of isolated gracilis muscle arterioles

2003 ◽  
Vol 285 (3) ◽  
pp. R536-R541 ◽  
Author(s):  
Fruzsina K. Johnson ◽  
Robert A. Johnson
Keyword(s):  
Carbon Monoxide ◽  
Methyl Ester ◽  
Aminolevulinic Acid ◽  
No Synthase ◽  
Gracilis Muscle ◽  
Sprague Dawley ◽  
No Donor ◽  
First Order ◽  
No Formation ◽  
Sprague Dawley Rats

Vascular tissues express heme oxygenase, which metabolizes heme to form carbon monoxide (CO). CO promotes relaxation of vascular smooth muscle but also inhibits nitric oxide (NO) formation. This study examines the hypothesis that CO promotes endothelium- and NO synthase-dependent vasoconstriction of isolated arterioles. Studies were conducted on pressurized first-order gracilis muscle arterioles isolated from anesthetized male Sprague-Dawley rats. Exogenous CO, as well as a heme precursor, δ-aminolevulinic acid (δ-ALA), constricted arterioles with intact endothelium pretreated with phenylephrine; these effects were abolished by removal of the endothelium. CO- and δ-ALA-induced vasoconstrictions were converted to dilations by pretreatment with an inhibitor of NO synthase, Nω-nitro-l-arginine methyl ester, or with Nω-nitro-l-arginine methyl ester and an NO donor, sodium nitroprusside. Furthermore, CO-induced vasoconstriction was prevented by pretreatment with the NO synthase substrate l-arginine. This study shows that exogenous, as well as endogenously formed, CO can promote endothelium-dependent vasoconstriction in isolated gracilis muscle arterioles. Because CO-induced vasoconstriction is abolished by NO synthase blockade and by l-arginine, CO most likely promotes endothelium-dependent vasoconstriction by inhibiting endothelial NO formation.

Hindlimb unweighting alters endothelium-dependent vasodilation and ecNOS expression in soleus arterioles

2000 ◽  
Vol 89 (4) ◽  
pp. 1483-1490 ◽  
Author(s):  
William G. Schrage ◽  
Christopher R. Woodman ◽  
M. Harold Laughlin
Keyword(s):  
Sodium Nitroprusside ◽  
Group Treatment ◽  
Day Treatment ◽  
Weight Bearing ◽  
Immunoblot Analysis ◽  
Sprague Dawley ◽  
Resistance Arteries ◽  
Protein Levels ◽  
Sprague Dawley Rats ◽  
Mrna And Protein Expression

The purpose of this study was to test the hypothesis that endothelium-dependent dilation is impaired in soleus resistance arteries from hindlimb-unweighted (HLU) rats. Male Sprague-Dawley rats (300–350 g) were exposed to HLU ( n = 14) or weight-bearing control (Con, n = 14) conditions for 14 days. After the 14-day treatment period, soleus first-order (1A) arterioles were isolated and cannulated with micropipettes to assess vasodilator responses to an endothelium-dependent dilator, ACh (10−9–10−4 M), and an endothelium-independent dilator, sodium nitroprusside (SNP, 10−9–10−4 M). Arterioles from HLU rats were smaller than Con arterioles (maximal passive diameter = 140 ± 4 and 121 ± 4 μm in Con and HLU, respectively) but developed similar spontaneous myogenic tone (43 ± 3 and 45 ± 3% in Con and HLU, respectively). Arteries from Con and HLU rats dilated in response to increasing doses of ACh, but dilation was impaired in arterioles from HLU rats ( P = 0.03), as was maximal dilation to ACh (85 ± 4 and 65 ± 4% possible dilation in Con and HLU, respectively). Inhibition of nitric oxide (NO) synthase (NOS) with N ω-nitro-l-arginine (300 μM) reduced ACh dilation by ∼40% in arterioles from Con rats and eliminated dilation in arterioles from HLU rats. The cyclooxygenase inhibitor indomethacin (50 μM) did not significantly alter dilation to ACh in either group. Treatment with N ω-nitro-l-arginine + indomethacin eliminated all ACh dilation in Con and HLU rats. Dilation to sodium nitroprusside was not different between groups ( P = 0.98). To determine whether HLU decreased expression of endothelial cell NOS (ecNOS), mRNA and protein levels were measured in single arterioles with RT-PCR and immunoblot analysis. The ecNOS mRNA and protein expression was significantly lower in arterioles from HLU rats than in Con arterioles (20 and 65%, respectively). Collectively, these data indicate that HLU impairs ACh dilation in soleus 1A arterioles, in part because of alterations in the NO pathway.

scholarly journals Recruitment of macrophages from the spleen contributes to myocardial fibrosis and hypertension induced by angiotensin II

2017 ◽  
Vol 18 (2) ◽  
pp. 147032031770665 ◽  
Author(s):  
Ning-Ping Wang ◽  
James Erskine ◽  
Wei-Wei Zhang ◽  
Rong-Hua Zheng ◽  
Li-Hui Zhang ◽  
...  
Keyword(s):  
Angiotensin Ii ◽  
Cardiac Fibrosis ◽  
Transforming Growth Factor ◽  
Transforming Growth Factor Β1 ◽  
At1 Receptor ◽  
Sprague Dawley ◽  
Monocyte Chemoattractant Protein 1 ◽  
Sprague Dawley Rats ◽  
Oxide Synthase ◽  
Endothelial Nitric Oxide

Introduction: The purpose of this study was to determine whether macrophages migrated from the spleen are associated with angiotensin II-induced cardiac fibrosis and hypertension. Methods: Sprague-Dawley rats were subjected to angiotensin II infusion in vehicle (500 ng/kg/min) for up to four weeks. In splenectomy, the spleen was removed before angiotensin II infusion. In the angiotensin II AT1 receptor blockade, telmisartan was administered by gastric gavage (10 mg/kg/day) during angiotensin II infusion. The heart and aorta were isolated for Western blot analysis and immunohistochemistry. Results: Angiotensin II infusion caused a significant reduction in the number of monocytes in the spleen through the AT1 receptor-activated monocyte chemoattractant protein-1. Comparison of angiotensin II infusion, splenectomy and telmisartan comparatively reduced the recruitment of macrophages into the heart. Associated with this change, transforming growth factor β1 expression and myofibroblast proliferation were inhibited, and Smad2/3 and collagen I/III were downregulated. Furthermore, interstitial/perivascular fibrosis was attenuated. These modifications occurred in coincidence with reduced blood pressure. At week 4, invasion of macrophages and myofibroblasts in the thoracic aorta was attenuated and expression of endothelial nitric oxide synthase was upregulated, along with a reduction in aortic fibrosis. Conclusions: These results suggest that macrophages when recruited into the heart and aorta from the spleen potentially contribute to angiotensin II-induced cardiac fibrosis and hypertension.

scholarly journals The importance of aminoguanidine and methylprednisolone administration in lung contusion after chest trauma

2021 ◽  
Vol 38 (4) ◽  
pp. 504-510
Author(s):  
Fatih ÇALIŞKAN ◽  
Hızır Ufuk AKDEMİR ◽  
Celal KATI ◽  
Latif DURAN ◽  
Tolga GÜVENÇ
Keyword(s):  
Combined Treatment ◽  
Serum Levels ◽  
The Other ◽  
Pulmonary Contusion ◽  
Sprague Dawley ◽  
Treatment Groups ◽  
Sprague Dawley Rats ◽  
Combined Use ◽  
Significant Difference ◽  
All Treatment

This study aims to evaluate the effect of the antioxidant and anti-inflammatory properties of aminoguanidine and metylprednisolone (MP) on lung tissue in a pulmonary contusion model of rats and evaluate whether their combined use improves treatment efficacy. This study included 35 female Sprague Dawley rats weighing 250-300 grams. The rats were divided into five groups as following: Sham; Pulmonary Contusion (PC); PC+MP, PC group treated with i.p methylprednisolone; PC+AG, PC group treated with i.p Aminoguanidine; and PC+AG+MP, PC group treated with Aminoguanidine and methylprednisolone. Each group had seven animals. Blood and lung tissues were studied biochemically and histopathologically. When compared groups according to serum levels of biomarkers, serum YKL-40, nitrate-nitrite, catalase, and TBARS levels were significant different. Serum YKL-40 levels were decreased after treatments in three groups. The serum YKL-40 levels in PC+AG group were lower than the other treatment groups, especially compared to PC + MP (p=0.028). Serum nitrate-nitrite levels were decreased in all treatment groups (PC+MP, PC+AG and PC+MP+AG). The lowest levels were measured in PC+MP+AG; but there was no statistically significant difference compared to PC group (p>0.05). Serum catalase levels were increased in all treatment groups. The higher levels were measured in PC+MP+AG than the other single treatment groups; however, PC+MP+AG and PC+MP were statistically significant different compared to PC group (p=0.001 and p=0.002 respectively). Serum TBARS levels were decreased in all treatment groups compared to Sham group (p<0.001) and PC group (p<0.001). The lowest levels were measured in PC+MP+AG compared to PC group (p<0.001). Histopathologic and immunohistochemical staining scores were decreased at all the treatment groups, especially PC+MP+AG. We suggest the use of combined treatment of methylprednisolone and aminoguanidine for the treatment of pulmonary contusion.

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