Grossini Elena, Caimmi Philippe Primo, Molinari Claudio, Mary David A S G, Uberti Francesca, Vacca Giovanni
Laboratorio di Fisiologia, Dipartimento di Medicina Clinica e Sperimentale, Facoltà di Medicina e Chirurgia, I-28100 Novara, Italy.
Cell Physiol Biochem. 2010;25(2-3):221-32. doi: 10.1159/000276556. Epub 2010 Jan 12.
In endothelial cells urocortin II has recently been found to activate nitric oxide synthase through cAMP-dependent and Ca(2+)-related pathway.
The present study was therefore planned to determine the mechanisms of urocortin II effect on Ca(2+) movements.
In Fura-2 loaded porcine aortic endothelial cells (PAE), the effects of urocortin II on [Ca(2+)]c were analyzed and compared with those of various K(+) channels agonists/antagonists.
In Fura-2 loaded PAE, urocortin II promoted a transient increase of [Ca(2+)]c mainly originating from an intracellular pool sensitive to thapsigargin and slightly from the extracellular space. In addition, urocortin II caused the hyperpolarization of plasma membrane through the opening of K(+) channels, which contributed to the increased [Ca(2+)]c. These effects were abolished by the corticotropin releasing factor receptors (CRFR2) blocker, the adenylyl cyclase and Ca(2+)-calmodulin-kinase (CaMKII) inhibitors and by blockers of K(+) channels. In addition, in PAE cultured in Na(+)-free medium or loaded with the plasma-membrane Ca(2+) pump inhibitor the urocortin II-evoked Ca(2+) transient was slower.
The results obtained show that urocortin II affects intracellular Ca(2+) homeostasis in PAE by both promoting a discharge of intracellular pool and by interfering with the operation of store-dependent channels through CRFR2-cAMP-CaMKII related signalling and K(+) channels opening.
最近发现，在内皮细胞中，尿皮质素II通过cAMP依赖途径和与Ca(2+)相关的途径激活一氧化氮合酶。
因此，本研究旨在确定尿皮质素II对Ca(2+)运动影响的机制。
在装载有Fura-2的猪主动脉内皮细胞（PAE）中，分析尿皮质素II对[Ca(2+)]c的影响，并与各种钾通道激动剂/拮抗剂的影响进行比较。
在装载有Fura-2的PAE中，尿皮质素II促进了[Ca(2+)]c的短暂升高，这主要源于对毒胡萝卜素敏感的细胞内池，少量源于细胞外空间。此外，尿皮质素II通过钾通道的开放导致质膜超极化，这有助于[Ca(2+)]c的增加。促肾上腺皮质激素释放因子受体（CRFR2）阻滞剂、腺苷酸环化酶和Ca(2+)-钙调蛋白激酶（CaMKII）抑制剂以及钾通道阻滞剂可消除这些作用。此外，在无钠培养基中培养的PAE或装载有质膜钙泵抑制剂的PAE中，尿皮质素II诱发的钙瞬变较慢。
所得结果表明，尿皮质素II通过促进细胞内池的释放以及通过CRFR2-cAMP-CaMKII相关信号传导和钾通道开放干扰储存依赖性通道的运作，从而影响PAE中的细胞内钙稳态。
