Centro de Investigaciones Cardiovasculares "Dr. Horacio E. Cingolani", Facultad de Ciencias Médicas, Universidad Nacional de La Plata-CONICET, La Plata 1900, Buenos Aires, Argentina.
Biomedicine Department, Health, Aarhus University, 8000 Aarhus, Midtjylland, Denmark.
Int J Mol Sci. 2024 Aug 19;25(16):8993. doi: 10.3390/ijms25168993.
The G-protein-coupled estrogen receptor (GPER) has been described to exert several cardioprotective effects. However, the exact mechanism involved in cardiac protection remains unclear. The aim of this study is to investigate the role of GPER activation on excitation-contraction coupling (ECC) and the possibility that such effect participates in cardioprotection. The cardiac myocytes of male Wistar rats were isolated with a digestive buffer and loaded with Fura-2-AM for the measurement of intracellular calcium transient (CaT). Sarcomere shortening (SS) and L-type calcium current (I) were also registered. The confocal technique was used to measure nitric oxide (NO) production in cells loaded with DAF-FM-diacetate. Cardiac myocytes exposed to 17-β-estradiol (E2, 10 nM) or G-1 (1 μM) for fifteen minutes decreased CaT, SS, and I. These effects were prevented using G-36 (antagonist of GPER, 1 μM), L-Name (NO synthase -NOS- inhibitor, 100 nM), or wortmannin (phosphoinositide-3-kinase -PI3K- inhibitor, 100 nM). Moreover, G1 increased NO production, and this effect was abolished in the presence of wortmannin. We concluded that the selective activation of GPER with E2 or G1 in the isolated cardiac myocytes of male rats induced a negative inotropic effect due to the reduction in I and the decrease in CaT. Finally, the pathway that we proposed to be implicated in these effects is PI3K-NOS-NO.
G 蛋白偶联雌激素受体 (GPER) 被描述为具有多种心脏保护作用。然而，涉及心脏保护的确切机制仍不清楚。本研究旨在探讨 GPER 激活对兴奋-收缩偶联 (ECC) 的作用，以及这种作用是否参与心脏保护。使用消化缓冲液分离雄性 Wistar 大鼠的心肌细胞，并加载 Fura-2-AM 以测量细胞内钙离子瞬变 (CaT)。还记录了肌节缩短 (SS) 和 L 型钙电流 (I)。共聚焦技术用于测量加载 DAF-FM-二乙酸的细胞中一氧化氮 (NO) 的产生。暴露于 17-β-雌二醇 (E2，10 nM) 或 G-1(1 μM) 十五分钟的心肌细胞降低了 CaT、SS 和 I。这些作用可以通过 G-36(GPER 拮抗剂，1 μM)、L-Name(一氧化氮合酶-NOS-抑制剂，100 nM) 或wortmannin(磷脂酰肌醇-3-激酶-PI3K-抑制剂，100 nM)来预防。此外，G1 增加了 NO 的产生，而这种作用在 wortmannin 存在下被消除。我们得出结论，在雄性大鼠的分离心肌细胞中，用 E2 或 G1 选择性激活 GPER 会由于 I 的减少和 CaT 的降低而导致负性变力作用。最后，我们提出的涉及这些作用的途径是 PI3K-NOS-NO。
