Adrenal-dependent modulation of the catalytic subunit isoforms of the Na<sup>+</sup>-K<sup>+</sup>-ATPase in aorta

Michea, Luis; Valenzuela, Viviana; Bravo, Ignacio; Schuster, Andrés; Marusic, Elisa T.

doi:10.1152/ajpendo.1998.275.6.e1072

Cited by 10 publications

(17 citation statements)

References 48 publications

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“…The expression and activity of Na + ,K + -ATPase and its a isoform are regulated by multiple factors such as developmental stage (27), hormones (28), endothelial factors (29) and the occurrence of hypertension (30,31).…”

Section: Discussionmentioning

confidence: 99%

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: 99%

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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“…Animals were anesthetized (Ketamine/ Xilacine) and adrenalectomized. 25 The ADX-DOCA group received DOCA (0.5 mg/100 grams body weight) daily. 25 The Ethics Committee of the Faculty of Medicine approved all protocols, according to National Institutes of Health Guide for the Care and Use of Laboratory Animals.…”

Section: Experimental Animalsmentioning

confidence: 99%

“…25 Protein was separated on 10% SDS-PAGE and Western blot was performed as described. 25 Primary antibody used was rabbit polyclonal anti-AT2 (H-143) diluted 1:200 (Santa Cruz Biotechnology, Inc). Densitometry analysis results were expressed as the relative band intensity compared with the control paired sample.…”

Section: Membrane Preparation and Western Blot Analysismentioning

confidence: 99%

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High-Salt Diet Inhibits Expression of Angiotensin Type 2 Receptor in Resistance Arteries

et al. 2005

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Abstract-Recent studies suggested that type 2 angiotensin receptor (AT2R) could contribute to regulation of blood pressure and/or vascular remodeling. A key question relates to the effects of potential modulators of vascular AT2R expression. In the present work, we evaluated if high salt intake (70 mmol/L NaCl in drinking water) could modulate rat mesenteric artery AT2R function and expression. Angiotensin II dose-response curves were studied in rat perfused pressurized small-diameter arteries in the presence of losartan (AT1R antagonist Key Words: mineralocorticoid Ⅲ sodium Ⅲ hypertension Ⅲ vascular remodeling Ⅲ apoptosis T he renin-angiotensin-aldosterone system (RAAS) regulates vascular tone, body fluid volume, electrolyte balance, hormonal secretion, and neuronal activity. The biological effects of angiotensin II (Ang II), the main effector peptide in the vasculature, are mediated by at least 2 receptor isofoms. 1,2 The type 1 receptor (AT1R) mediates vasoconstriction, sympathetic facilitation, and trophic effects. The type 2 receptor (AT2R) is widely expressed during fetal development, whereas in the adult its expression has been detected in many different vessel types, including mesenteric, coronary, and renal arteries. 3-6 AT2R has opposite effects to those of AT1R, ie, it promotes cell apoptosis and inhibits cell proliferation. 6,7 AT2R also attenuates the pressor action of Ang II 8 and mediates vasodilation. 9,10 Recently, it has been shown that Ang II relaxes small mesenteric arteries via AT2R when AT1R are blocked. [11][12][13] Interestingly, the expression of AT2R is increased in several pathologic conditions such as vascular injury, 14 cardiac remodeling, congestive heart failure, and myocardial infarction. 15,16 It has been suggested that in adults the presence of AT2R in vascular tissues may be playing a role in vascular tone and/or tissue remodeling. [17][18][19] Therefore, a key and complex question that arises is how AT1R and AT2R expression are modulated. Several studies indicate interaction between Ang II and aldosterone, affecting the expression of ATRs. The expression of AT1R appears to be induced by Ang II in vascular smooth muscle, 4 and mineralocorticoids potentiate the action of Ang II in cultured rat vascular smooth muscle cells (VSMCs) by increasing the number of AT1R. 20,21 However, there are few data concerning the physiological regulation of AT2R expression. Dietary sodium depletion, which increases RAAS activity, enhances renal AT2 receptor function 10,22 and expression in both young and mature adult rats, mainly in the glomeruli and interstitial cells. 23 Induction of AT2R-mediated modulation of blood pressure was described in rats fed with a synthetic diet, an effect attributed to the stimulation of the RAAS. 8 Bonnet et al 24 have shown that Ang II infusion in the rat induces the expression of AT2R in the mesenteric vasculature. Nevertheless, it is not clear whether Ang II directly mediates the increased AT2R expression or if it is secondary to direct aldosterone action on arte...

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“…Blots were developed by enhanced chemiluminescence (PerkinElmer Life Sciences) with horseradish peroxidase-conjugated secondary antibodies (anti-mouse IgG H&L chain, goat; KPL). Films (Kodak BioMax ML) were placed in contact with the membranes in cassettes containing intensifying screens, and four to five plates with different exposure times were used to avoid film saturation as indicated by Michea et al (42). Computer scanning densitometry analysis quantified the signal intensity present in each lane.…”

Section: Animalsmentioning

confidence: 99%

Estradiol-induced expression of Na⁺-K⁺-ATPase catalytic isoforms in rat arteries: gender differences in activity mediated by nitric oxide donors

Palacios

Marusic

López

et al. 2004

American Journal of Physiology-Heart and Circulatory Physiology

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We tested the hypothesis that previously demonstrated gender differences in ACh-induced vascular relaxation could involve diverse Na+-K+-ATPase functions. We determined Na+-K+-ATPase by measuring arterial ouabain-sensitive 86Rb uptake in response to ACh. We found a significant increase of Na+ pump activity only in aortic rings from female rats (control 206 ± 11 vs. 367 ± 29 nmol 86Rb/K·min–1·g wt tissue–1; P < 0.01). Ovariectomy eliminated sex differences in Na+-K+-ATPase function, and chronic in vivo hormone replacement with 17β-estradiol restored the ACh effect on Na+-K+-ATPase. Because ACh acts by enhancing production of NO, we examined whether the NO donor sodium nitroprusside (SNP) mimics the action of ACh on Na+-K+-ATPase activity. SNP increased ouabain-sensitive 86Rb uptake in denuded female arteries (control 123 ± 7 vs. 197 ± 12 nmol 86Rb/K·min–1·g wt tissue–1; P < 0.05). Methylene blue (an inhibitor of guanylate cyclase) and KT-5823 (a cGMP-dependent kinase inhibitor) blocked the stimulatory action of SNP. Exposure of female thoracic aorta to the Na+/K+ pump inhibitor ouabain significantly decreased SNP-induced and ACh-mediated relaxation of aortic rings. At the molecular level, Western blot analysis of arterial tissue revealed significant gender differences in the relative abundance of catalytic isoforms of Na+-K+-ATPase. Female-derived aortas exhibited a greater proportion of α2-isoform (44%) compared with male-derived aortas. Furthermore, estradiol upregulated the expression of α2 mRNA in male arterial explants. Our results demonstrate that enhancement of ACh-induced relaxation observed in female rats may be in part explained by 1) NO-dependent increased Na+-K+-ATPase activity in female vascular tissue and 2) greater abundance of Na+-K+-ATPase α2-isoform in females.

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Adrenal-dependent modulation of the catalytic subunit isoforms of the Na⁺-K⁺-ATPase in aorta

Cited by 10 publications

References 48 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

High-Salt Diet Inhibits Expression of Angiotensin Type 2 Receptor in Resistance Arteries

Estradiol-induced expression of Na⁺-K⁺-ATPase catalytic isoforms in rat arteries: gender differences in activity mediated by nitric oxide donors

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Adrenal-dependent modulation of the catalytic subunit isoforms of the Na+-K+-ATPase in aorta

Cited by 10 publications

References 48 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

High-Salt Diet Inhibits Expression of Angiotensin Type 2 Receptor in Resistance Arteries

Estradiol-induced expression of Na+-K+-ATPase catalytic isoforms in rat arteries: gender differences in activity mediated by nitric oxide donors

Contact Info

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Resources

About

Adrenal-dependent modulation of the catalytic subunit isoforms of the Na⁺-K⁺-ATPase in aorta

Estradiol-induced expression of Na⁺-K⁺-ATPase catalytic isoforms in rat arteries: gender differences in activity mediated by nitric oxide donors