Michea Luis, Delpiano Ana M, Hitschfeld Catalina, Lobos Lorena, Lavandero Sergio, Marusic Elisa T
Laboratory of Cellular and Molecular Physiology, Faculty of Medicine, University Los Andes, S. Carlos Apoquindo 2200, Las Condes, 6782468 Santiago, Chile.
Endocrinology. 2005 Mar;146(3):973-80. doi: 10.1210/en.2004-1130. Epub 2004 Nov 18.
There is increasing evidence for rapid nongenomic effects of aldosterone. Aldosterone has been demonstrated to alter intracellular pH and calcium in isolated cells. However, few studies have correlated these effects with aldosterone-mediated physiological responses. Therefore, we studied rapid effects of aldosterone on vascular reactivity, intracellular Ca2+, and pH in resistance vessels. Furthermore, we explored whether the new antimineralocorticoid drug eplerenone could effectively block nongenomic aldosterone-mediated effects. The vasoconstrictor action of aldosterone was examined directly by determining the diameter of small resistance mesenteric vessels (160-200 microm resting diameter), simultaneously with intracellular pH or Ca2+. Aldosterone (10 nm) caused a rapid constriction of resistance vessels (8.1% +/- 1.0% reduction in the diameter below control conditions, P < 0.05). Aldosterone potentiated phenylephrine-mediated constriction in small and large mesenteric vessels. Aldosterone induced a rapid increase of intracellular Ca2+ and cellular alkalinization. Vasoconstrictor action of aldosterone and nongenomic effects on the sodium-proton exchanger (NHE1) activity or intracellular Ca2+ responses was abolished by eplerenone. The vasoconstrictor response of aldosterone was related to phosphatidylinositol 3-kinase (PI3-K): the hormone decreased protein kinase B phosphorylation; pharmacological inhibition of PI3-K (10 microm LY294002 or 1 microm wortmannin) increased arterial contractility. Inhibitors of ERK 1/2 phosphorylation (15 microm PD98059) had no effect on aldosterone-mediated vasoconstriction. Inhibition of protein kinase C with 1 microm bi-sindolylmaleimide I and/or inhibition of NHE1 with 100 microm amiloride abolished aldosterone vasoconstrictor action of resistance mesenteric arteries. We conclude that aldosterone-mediated increase in vascular tone is related to a nongenomic mechanism that involves protein kinase C, PI3-K, and NHE1 activity. Eplerenone is an effective blocker of nongenomic effects of aldosterone in vascular tissue.
越来越多的证据表明醛固酮具有快速的非基因组效应。醛固酮已被证明可改变分离细胞内的pH值和钙含量。然而，很少有研究将这些效应与醛固酮介导的生理反应联系起来。因此，我们研究了醛固酮对阻力血管的血管反应性、细胞内Ca2+和pH值的快速影响。此外，我们探讨了新型抗盐皮质激素药物依普利酮是否能有效阻断非基因组醛固酮介导的效应。通过测定小阻力肠系膜血管（静息直径160 - 200微米）的直径，同时检测细胞内pH值或Ca2+，直接研究醛固酮的血管收缩作用。醛固酮（10纳米）导致阻力血管快速收缩（直径比对照条件下降低8.1%±1.0%，P < 0.05）。醛固酮增强了去氧肾上腺素介导的小和大肠系膜血管收缩。醛固酮诱导细胞内Ca2+快速增加和细胞碱化。依普利酮消除了醛固酮的血管收缩作用以及对钠-质子交换体（NHE1）活性或细胞内Ca2+反应的非基因组效应。醛固酮的血管收缩反应与磷脂酰肌醇3激酶（PI3-K）有关：该激素降低蛋白激酶B的磷酸化；PI3-K的药理学抑制（10微米LY294002或1微米渥曼青霉素）增加动脉收缩性。细胞外信号调节激酶1/2磷酸化的抑制剂（15微米PD98059）对醛固酮介导的血管收缩没有影响。用1微米双吲哚马来酰亚胺I抑制蛋白激酶C和/或用100微米氨氯地平抑制NHE1消除了醛固酮对肠系膜阻力动脉的血管收缩作用。我们得出结论，醛固酮介导的血管张力增加与一种涉及蛋白激酶C、PI3-K和NHE1活性的非基因组机制有关。依普利酮是血管组织中醛固酮非基因组效应的有效阻断剂。
