scholarly journals Exercise Training Enhances Flow-Mediated Dilation in Spontaneously Hypertensive Rats

2011 ◽  
pp. 589-597 ◽  
Author(s):  
F. GÜNDÜZ ◽  
G. KOÇER ◽  
S. ÜLKER ◽  
H. J. MEISELMAN ◽  
O. K. BAŞKURT ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Exercise Training ◽  
Spontaneously Hypertensive Rats ◽  
Flow Mediated Dilation ◽  
Hypertensive Rats ◽  
Spontaneously Hypertensive ◽  
Wky Rats ◽  
Significant Attenuation ◽  
Isolated Arteries ◽  
Oxide Synthase

This study investigated the effect of exercise training on the flow-mediated dilation (FMD) in gastrocnemius muscle arteries from spontaneously hypertensive rats (SHR). SHR and WKY rats were divided into sedentary and exercised groups. After swimming exercise for eight weeks, the isolated arteries were mounted on pressurized myograph and FMD responses examined. The role of nitric oxide (NO), prostaglandins (PGs) and endothelium derived hyperpolarizing factor (EDHF) on FMD were assessed by obtaining dilation responses in the presence and absence of pharmacological antagonists. Nω-nitro-L-arginine methyl ester (L-NAME), indomethacin (INDO) and tetraethylamonium (TEA) were used to inhibit nitric oxide synthase, cyclooxygenase and EDHF-mediated responses, respectively. The FMD response was significantly blunted in arteries of SHR compared with WKY rats, and, improved by exercise training in SHR (SHR-ET) group. In SHR arteries, L NAME and TEA did not affect dilation responses to flow, while INDO led to a significant enhancement in this response. Although dilation response was not altered by L-NAME in arteries obtained from trained SHR, TEA caused a significant attenuation and INDO led to significant increases. These results demonstrate that exercise training improves FMD in SHR, and, this enhancement induced by exercise training occurs through EDHF-mediated mechanism(s).

scholarly journals Combination of Exercise Training and SOD Mimetic Tempol Enhances Upregulation of Nitric Oxide Synthase in the Kidney of Spontaneously Hypertensive Rats

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Pengyu Cao ◽  
Osamu Ito ◽  
Daisuke Ito ◽  
Rong Rong ◽  
Yang Zheng ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Exercise Training ◽  
Nadph Oxidase ◽  
Oxidase Activity ◽  
Spontaneously Hypertensive Rats ◽  
Hypertensive Rats ◽  
Sod Activity ◽  
Spontaneously Hypertensive ◽  
Nadph Oxidase Activity ◽  
Expression Levels

Both exercise training (Ex) and superoxide dismutase (SOD) mimetic tempol have antihypertensive and renal protective effects in rodent models of several hypertensions. We recently reported that Ex increases nitric oxide (NO) production and the expression levels of endothelial and neuronal NO synthase (eNOS and nNOS) in the kidney and aorta of the spontaneously hypertensive rats (SHR) and normotensive Wistar–Kyoto rats (WKY). We also found that endogenous hydrogen peroxide (H2O2) upregulates the expression levels of eNOS and nNOS in SHR. To elucidate the mechanism of the Ex-upregulated NO system in the kidney, we examined the additive effect of Ex and tempol on the renal NO system in SHR and WKY. Our data showed that, in SHR, both Ex and tempol increase the levels of H2O2 and nitrate/nitrite (NOx) in plasma and urine. We also observed an increased renal NOS activity and upregulated expression levels of eNOS and nNOS with decreased NADPH oxidase activity. The effects of the combination of Ex and tempol on these variables were cumulate in SHR. On the other hand, we found that Ex increases these variables with increased renal NADPH oxidase activity, but tempol did not change these variables or affect the Ex-induced upregulation in the activity and expression of NOS in WKY. The SOD activity in the kidney and aorta was activated by tempol only in SHR, but not in WKY; whereas Ex increased SOD activity only in the aorta in both SHR and WKY. These results indicate that Ex-induced endogenous H2O2 produced in the blood vessel and other organs outside of the kidney may be carried to the kidney by blood flow and stimulates the NO system in the kidney.

Expression of endothelin receptors and nitric oxide synthase in the brain of stroke-prone spontaneously hypertensive rats with cerebral apoplexy

1997 ◽  
Vol 756 (1-2) ◽  
pp. 61-67 ◽  
Author(s):  
Yasuko Sakurai-Yamashita ◽  
Kimihiro Yamashita ◽  
Yasufumi Kataoka ◽  
Akihiko Himeno ◽  
Masami Niwa ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Nitric Oxide Synthase ◽  
Spontaneously Hypertensive Rats ◽  
Endothelin Receptors ◽  
Hypertensive Rats ◽  
Spontaneously Hypertensive ◽  
Oxide Synthase ◽  
The Brain

scholarly journals Rapamycin Induces an eNOS (Endothelial Nitric Oxide Synthase) Dependent Increase in Brain Collateral Perfusion in Wistar and Spontaneously Hypertensive Rats

Stroke ◽  
2020 ◽  
Vol 51 (9) ◽  
pp. 2834-2843
Author(s):  
Daniel J. Beard ◽  
Zhaojin Li ◽  
Anna M. Schneider ◽  
Yvonne Couch ◽  
Marilyn J. Cipolla ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Nitric Oxide Synthase ◽  
Spontaneously Hypertensive Rats ◽  
Infarct Volume ◽  
Hypertensive Rats ◽  
Spontaneously Hypertensive ◽  
Oxide Synthase ◽  
Endothelial Nitric Oxide

Background and Purpose: Rapamycin is a clinically approved mammalian target of rapamycin inhibitor that has been shown to be neuroprotective in animal models of stroke. However, the mechanism of rapamycin-induced neuroprotection is still being explored. Our aims were to determine if rapamycin improved leptomeningeal collateral perfusion, to determine if this is through eNOS (endothelial nitric oxide synthase)-mediated vessel dilation and to determine if rapamycin increases immediate postreperfusion blood flow. Methods: Wistar and spontaneously hypertensive rats (≈14 weeks old, n=22 and n=15, respectively) were subjected to ischemia by middle cerebral artery occlusion (90 and 120 minutes, respectively) with or without treatment with rapamycin at 30-minute poststroke. Changes in middle cerebral artery and collateral perfusion territories were measured by dual-site laser Doppler. Reactivity to rapamycin was studied using isolated and pressurized leptomeningeal anastomoses. Brain injury was measured histologically or with triphenyltetrazolium chloride staining. Results: In Wistar rats, rapamycin increased collateral perfusion (43±17%), increased reperfusion cerebral blood flow (16±8%) and significantly reduced infarct volume (35±6 versus 63±8 mm 3 , P <0.05). Rapamycin dilated leptomeningeal anastomoses by 80±9%, which was abolished by nitric oxide synthase inhibition. In spontaneously hypertensive rats, rapamycin increased collateral perfusion by 32±25%, reperfusion cerebral blood flow by 44±16%, without reducing acute infarct volume 2 hours postreperfusion. Reperfusion cerebral blood flow was a stronger predictor of brain damage than collateral perfusion in both Wistar and spontaneously hypertensive rats. Conclusions: Rapamycin increased collateral perfusion and reperfusion cerebral blood flow in both Wistar and comorbid spontaneously hypertensive rats that appeared to be mediated by enhancing eNOS activation. These findings suggest that rapamycin may be an effective acute therapy for increasing collateral flow and as an adjunct therapy to thrombolysis or thrombectomy to improve reperfusion blood flow.

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