Role of endothelium in dilator responses of spontaneously hypertensive rat arteries.

Konishi, M; Su, Che

doi:10.1161/01.hyp.5.6.881

Cited by 384 publications

(176 citation statements)

References 11 publications

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“…In exercised SHR and WKY rats, we observed a greater increase in aortic conductance compared with sedentary rats, suggesting an enhanced vasodilatation in the hindlimb in exercised animals evoked by inhibition of the commNTS. This vasodilatation observed in the hindlimb was much greater in swimming WKY rats than in SHR, likely due to the impaired vasorelaxation in SHR as described in earlier studies (2,4,18,20,25). In contrast, the mesenteric bed showed no significant changes in conductance after inhibition of the commNTS comparing exercised and sedentary SHR and WKY rats.…”

Section: Discussionsupporting

confidence: 53%

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Exercise changes regional vascular control by commissural NTS in spontaneously hypertensive rats

Ogihara

Schoorlemmer

Levada

et al. 2010

American Journal of Physiology-Regulatory, Integrative and Comp

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Ogihara CA, Schoorlemmer GHM, Levada AC, Pithon-Curi TC, Curi R, Lopes OU, Colombari E, Sato MA. Exercise changes regional vascular control by commissural NTS in spontaneously hypertensive rats. Am J Physiol Regul Integr Comp Physiol 299: R291-R297, 2010. First published April 21, 2010 doi:10.1152/ajpregu.00055.2009.-Inhibition of the commissural nucleus of the solitary tract (commNTS) induces a fall in sympathetic nerve activity and blood pressure in spontaneously hypertensive rats (SHR), which suggests that this subnucleus of the NTS is a source of sympathoexcitation. Exercise training reduces sympathetic activity and arterial pressure. The purpose of the present study was to investigate whether the swimming exercise can modify the regional vascular responses evoked by inhibition of the commNTS neurons in SHR and normotensive Wistar-Kyoto (WKY) rats. Exercise consisted of swimming, 1 h/day, 5 days/wk for 6 wks, with a load of 2% of the body weight. The day after the last exercise session, the rats were anesthetized with intravenous ␣-chloralose, tracheostomized, and artificially ventilated. The femoral artery was cannulated for mean arterial pressure (MAP) and heart rate recordings, and Doppler flow probes were placed around the lower abdominal aorta and superior mesenteric artery. Microinjection of 50 mM GABA into the commNTS caused similar reductions in MAP in swimming and sedentary SHR (Ϫ25 Ϯ 6 and Ϫ30 Ϯ 5 mmHg, respectively), but hindlimb vascular conductance increased twofold in exercised vs. sedentary SHR (54 Ϯ 8 vs. 24 Ϯ 5%). GABA into the commNTS caused smaller reductions in MAP in swimming and sedentary WKY rats (Ϫ20 Ϯ 4 and Ϫ16 Ϯ 2 mmHg). Hindlimb conductance increased fourfold in exercised vs. sedentary WKY rats (75 Ϯ 2% vs. 19 Ϯ 3%). Therefore, our data suggest that the swimming exercise induced changes in commNTS neurons, as shown by a greater enhancement of hindlimb vasodilatation in WKY vs. SHR rats in response to GABAergic inhibition of these neurons.GABA; cardiovascular; citrate synthase THE NUCLEUS OF THE SOLITARY tract (NTS) is the primary site in the central nervous system that receives the afferents arising from arterial baro-and chemoreceptors (10, 15). The intermediate NTS receives inputs particularly from arterial baroreceptors, but some of these afferents achieve the commNTS (10, 16). The commNTS also receives inputs from arterial chemoreceptors, and seems to be highly sensitive to carotid chemoreceptor stimulation (8, 9, 11).The possible role of the commNTS as a source of sympathoexcitation was first shown by Nelson et al. (33), which demonstrated that nanoliter injections of L-glutamate into the commNTS evoke elevations in heart rate and arterial pressure mediated by the sympathetic nervous system. Electrolytic lesions or chemical inhibition of the commNTS have been shown to markedly decrease the splanchnic sympathetic nerve activity and arterial pressure in spontaneously hypertensive rats (SHR), which suggested that this subnucleus of the NTS contains neurons tonically active in S...

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Section: Discussionsupporting

confidence: 53%

“…Muscles were removed, frozen in liquid nitrogen, and stored at Ϫ70°C. Citrate synthase activity was determined following the method described by Alp (1) and used in previous studies (25,29). Soleus muscles from both legs of each animal were homogenized in an extraction buffer (50 mM Tris·HCl and 1 mM EDTA, pH 7.4).…”

Section: Methodsmentioning

confidence: 99%

Exercise changes regional vascular control by commissural NTS in spontaneously hypertensive rats

Ogihara

Schoorlemmer

Levada

et al. 2010

American Journal of Physiology-Regulatory, Integrative and Comp

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“…It has been shown previously that the relaxation response of isolated aortic strips to ACh from spontaneously hypertensive rats and New Zealand hypertensive rats is reduced when compared to that in strips from age-matched, normotensive, Wistar Kyoto rats (Cheng & Shibata, 1981;Konishi & Su, 1983;Winquist et al 1984a). In the present study, a similar result was observed in diabetic rats.…”

Section: Discussionmentioning

confidence: 93%

“…Changes in the responsiveness of vascular smooth muscle in vitro to ACh have been observed in pathological states, such as hypertension and atherosclerosis. In such cases, release of EDRF might be reduced (Konishi & Su, 1983;Winquist et al, 1984a;Jayakody et al, 1985).…”

Section: Discussionmentioning

confidence: 99%

Impairment of endothelium‐dependent relaxation and changes in levels of cyclic GMP in aorta from streptozotocin‐induced diabetic rats

Kamata

Miyata

Kasuya

1989

British J Pharmacology

282

158

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1 Acetylcholine (ACh)-induced relaxation of aortic strips with endothelium and production of cyclic GMP between streptozotocin-induced diabetic and age-matched control rats were compared. 2 The concentration-response curve for ACh-induced relaxation was shifted to the right in diabetic rats. IC50 values for ACh were 4.57 + 0.67 x 10-8IM and 1.00 + 0.87 x 10-7M in aortic strips from age-matched control and diabetic rats, respectively (n = 6, P < 0.05). 3 Relaxations produced by atrial natriuretic peptide (ANP) in diabetic aortae were similar to those in age-matched vessels. 4 Relaxations produced by sodium nitroprusside (SNP) in diabetic aortae were similar to those in age-matched vessels. 5 Basal levels of cyclic GMP and ACh-induced production of cyclic GMP were significantly decreased in diabetic rats. 6 These results suggest that functional changes in endothelium but not in guanylate cyclase activity in the aorta may occur in diabetes, and, thus, spontaneous and ACh-induced formation of cyclic GMP may be decreased. This decrease in production of cyclic GMP may be responsible for the decreased response of the aorta to the relaxant effect of ACh.

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“…Endothelium-dependent relaxations to acetylcholine (ACh) have been shown to be impaired in aortae of spontaneously hypertensive rats (SHR) (Konishi & Su, 1983; Vanhoutte & I Author for correspondence. Luscher, 1986), 1-clip, 2-kidney and DOCA-salt hypertensive rats (Van de Voorde & Leusen, 1986) compared to normotensive controls.…”

Section: Introductionmentioning

confidence: 99%

Study of mechanisms of glucocorticoid hypertension in rats: endothelial related changes and their amelioration by dietary fish oils

Yin

Chu

Beilin

1992

British J Pharmacology

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1 To investigate possible mechanisms of increased systolic blood pressure after 1 weeks treatment with dexamethasone and its amelioration by fish oil feeding, we have examined the reactivity of aortic rings and perfused mesenteric resistance vessels. 2 Thirty six Sprague-Dawley rats were initially divided into two groups and fed a semisynthetic diet containing either (10% by weight) hydrogenated coconut oil and safflower oil mixture (HCO/S) (24 rats) or fish oil (12 rats) for 5 weeks. From the end of the fourth week, dexamethasone (1.25 mg ml-') in drinking water, was given to half the rats on hydrogenated coconut oil (HCO/S + Dex) and to the fish oil-fed group (fish oil + Dex). 3 One week of dexamethasone treatment raised systolic blood pressure in the HCO/S + Dex rats but not in the fish oil + Dex group. 4 Endothelium-dependent relaxation to acetylcholine (ACh) was decreased in aortic rings taken from HCO/S + Dex rats compared to rats on HCO/S alone. Relaxant responses to ACh of aortic rings from rats given fish oil + Dex were intermediate between the three groups. Aortic endothielium-independent responses to sodium nitroprusside (SNP) were unchanged between the groups, while aortic contractile responses to noradrenaline were similar in all the groups. 5 In the perfused mesenteric resistance artery, sensitivity to noradrenaline was decreased in rats given fish oil and dexamethasone compared to the other two groups. There were no differences in resistance vessel relaxation to ACh or SNP between groups. 6 Serum corticosterone levels, used as a marker of dexamethasone absorption, were substantially suppressed in dexamethasone-treated rats but levels were higher in rats on fish oil than on HCO/S diets. 7 We suggest that the glucocorticoid-induced rise in systolic blood pressure may be due in part to decreased aortic compliance as a consequence of impaired endothelium-dependent relaxation and perhaps reduced nitric oxide synthesis. Fish oil feeding may ameliorate this rise in blood pressure through (i) changes in dexamethasone absorption, (ii) decrease in reactivity to noradrenaline of perfused mesenteric resistance arteries, (iii) an increase in endothelium-dependent relaxation to ACh or a combination of these three factors.

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Role of endothelium in dilator responses of spontaneously hypertensive rat arteries.

Cited by 384 publications

References 11 publications

Exercise changes regional vascular control by commissural NTS in spontaneously hypertensive rats

Exercise changes regional vascular control by commissural NTS in spontaneously hypertensive rats

Impairment of endothelium‐dependent relaxation and changes in levels of cyclic GMP in aorta from streptozotocin‐induced diabetic rats

Study of mechanisms of glucocorticoid hypertension in rats: endothelial related changes and their amelioration by dietary fish oils

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