Increased contractile response induced with ouabain is abolished by thapsigargin in aorta of renal hypertensive rats

Cerón, Patricia; Bendhack, Lusiane Maria

doi:10.1016/s0306-3623(97)00260-7

Cited by 9 publications

(7 citation statements)

References 19 publications

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“…Previous reports have demonstrated that higher doses of ouabain sensitize the contractile response to a-adrenergic agonists and to KCl in 1K1C rats (21,22). The same occurs with DOCA-salt rats in which ouabain treatment increased even more the pressor responses (23).…”

Section: Discussionmentioning

confidence: 55%

Effects of small doses of ouabain on the arterial blood pressure of anesthetized hypertensive and normotensive rats

Rossoni

Pinto

Vassallo

2001

Braz J Med Biol Res

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Ouabain increases vascular resistance and may induce hypertension by inhibiting the Na + pump. The effects of 0.18 and 18 µg/kg, and 1.8 mg/ kg ouabain pretreatment on the phenylephrine (PHE; 0.1, 0.25 and 0.5 µg, in bolus)-evoked pressor responses were investigated using anesthetized normotensive (control and uninephrectomized) and hypertensive (1K1C and DOCA-salt treated) rats. Treatment with 18 µg/kg ouabain increased systolic and diastolic blood pressure in all groups studied. However, the magnitude of this increase was larger for the hypertensive 1K1C and DOCA-salt rats than for normotensive animals, while the pressor effect of 0.18 µg/kg ouabain was greater only in DOCA-salt rats. A very large dose (1.8 mg/kg) produced toxic effects on the normotensive control but not on uninephrectomized or 1K1C rats. Rat tail vascular beds were perfused to analyze the effects of 10 nM ouabain on the pressor response to PHE. In all animals, 10 nM ouabain increased the PHE pressor response, but this increase was larger in hypertensive DOCA-salt rats than in normotensive and 1K1C rats. Results suggested that a) increases in diastolic blood pressure induced by 18 µg/kg ouabain were larger in hypertensive than normotensive rats; b) in DOCA-salt rats, smaller ouabain doses had a stronger effect than in other groups; c) hypertensive and uninephrectomized rats were less sensitive to toxic doses of ouabain, and d) after treatment with 10 nM ouabain isolated tail vascular beds from DOCA-salt rats were more sensitive to the pressor effect of PHE than those from normotensive and 1K1C hypertensive rats. These data suggest that very small doses of ouabain, which might produce nanomolar plasma concentrations, enhance pressor reactivity in DOCA-salt hypertensive rats, supporting the idea that endogenous ouabain may contribute to the increase and maintenance of vascular tone in hypertension. Correspondence

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Section: Discussionmentioning

confidence: 55%

Effects of small doses of ouabain on the arterial blood pressure of anesthetized hypertensive and normotensive rats

Rossoni

Pinto

Vassallo

2001

Braz J Med Biol Res

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“…Several studies [11,14,[24][25][26][27][28][29] suggest that hypertensive rats are more sensitive to the acute pressor effect of ouabain both in vivo and in vitro. Previous results from our group revealed that the acute hypertensive effect of ouabain (administered at a nanomolar range) and the potentiator effect on phenylephrine-induced vasoconstriction was larger in spontaneously, N G -nitro-L-arginine methyl ester (L-NAME), deoxycorticosterone acetate (DOCA)-salt and one kidney, one clip (1K1C) hypertensive rats compared with their respective normotensive controls [11,14,25,28,29].…”

Section: Introductionmentioning

confidence: 99%

Chronic ouabain treatment exacerbates blood pressure elevation in spontaneously hypertensive rats: the role of vascular mechanisms

Xavier

Davel

Fukuda

et al. 2009

Journal of Hypertension

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Chronic ouabain treatment further increases the raised blood pressure of SHRs. This appears to involve a vascular mechanism, related to a reduced vasodilator influence of nitric oxide and endothelium-derived hyperpolarizing factor and increased production of vasoconstrictor prostanoids by COX-2. These data suggest that the increased plasma levels of ouabain could play an important role in the maintenance of hypertension and the impairment of endothelial function.

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“…Indeed, a number of studies indicate that vascular growth and remodeling may play a central role in the pathogenesis of hypertension (15,22,36). In at least several forms of hypertension, however, the remodeling appears to be an adaptive response rather than the cause of the elevated BP (7,22,34).Many investigators have compared the acute effects of ouabain on arteries isolated from normotensive and hypertensive rats, but most have studied large arteries (e.g., aorta) and high concentrations (Ͼ10 M) of ouabain (9,40). A few studies on arteries from OH rats may provide information about the pathogenesis of the hypertension, but the data are inconsistent.…”

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confidence: 99%

Low-dose ouabain constricts small arteries from ouabain-hypertensive rats: implications for sustained elevation of vascular resistance

Zhang¹,

Hamlyn²,

Karashima³

et al. 2009

American Journal of Physiology-Heart and Circulatory Physiology

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Low-dose ouabain constricts small arteries from ouabain-hypertensive rats: implications for sustained elevation of vascular resistance. Am J Physiol Heart Circ Physiol 297: H1140 -H1150, 2009. First published July 17, 2009 doi:10.1152/ajpheart.00436.2009.-Prolonged ouabain administration to normal rats causes sustained blood pressure (BP) elevation. This ouabain-induced hypertension (OH) has been attributed, in part, to the narrowing of third-order resistance arteries (ϳ320 m internal diameter) as a result of collagen deposition in the artery media (see Ref. 6). Here we describe the structural and functional properties of fourth-order mesenteric small arteries from control and OH rats, including the effect of low-dose ouabain on myogenic tone in these arteries. Systolic BP in OH rats was 138 Ϯ 3 versus 124 Ϯ 4 mmHg in controls (P Ͻ 0.01). Pressurized (70 mmHg) control and OH arteries, with only a single layer of myocytes, both had ϳ165-m internal diameters and ϳ20-m wall thicknesses. Even after fixation, despite vasoconstriction, the diameters and wall thicknesses did not differ between control and OH fourth-order arteries, whereas in third-order arteries, both parameters were significantly smaller in OH than in controls. Myogenic reactivity was significantly augmented in OH fourth-order arteries. Nevertheless, phenylephrine-(1 M) and high K ϩ -induced vasoconstrictions and acetylcholine-induced vasodilation were comparable in control and OH arteries. Vasoconstrictions induced by 5 M phenylephrine and by 10 mM caffeine in Ca 2ϩ -free media indicated that releasable sarcoplasmic reticulum Ca 2ϩ stores were normal in OH arteries. Importantly, 100 nM ouabain constricted both control and OH arteries by ϳ26 m, indicating that this response was not downregulated in OH rats. This maximal ouabain-induced constriction corresponds to a ϳ90% increase in resistance to flow in these small arteries; thus ouabain at EC 50 of ϳ0.66 nM should raise resistance by ϳ35%. We conclude that dynamic constriction in response to circulating nanomolar ouabain in small arteries likely makes a major contribution to the increased vascular tone and BP in OH rats. myogenic reactivity; resistance artery OUABAIN, A MAMMALIAN adrenocortical hormone (4,20,21,28), apparently plays an important role in the pathogenesis of hypertension in humans and rodents. About 50% of patients with essential hypertension and a majority of patients with adrenocortical adenomas and hypertension have elevated plasma endogenous ouabain (EO) (42,45). In normal humans, ouabain infusion increases peripheral vascular resistance, reduces blood flow, and elevates blood pressure (BP) (35, 47).Moreover, high-dietary salt increases plasma EO levels in normal men (32).Elevated EO levels are also observed in rats with DOCA-salt hypertension (20), reduced renal mass hypertension (24), and Milan strain hypertension (14). Additionally, the chronic treatment of normal rats and mice with ouabain elevates BP, i.e., ouabain-induced hypertension (OH) (12, 33, 50). Although digoxin, lik...

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Increased contractile response induced with ouabain is abolished by thapsigargin in aorta of renal hypertensive rats

Cited by 9 publications

References 19 publications

Effects of small doses of ouabain on the arterial blood pressure of anesthetized hypertensive and normotensive rats

Effects of small doses of ouabain on the arterial blood pressure of anesthetized hypertensive and normotensive rats

Chronic ouabain treatment exacerbates blood pressure elevation in spontaneously hypertensive rats: the role of vascular mechanisms

Low-dose ouabain constricts small arteries from ouabain-hypertensive rats: implications for sustained elevation of vascular resistance

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