Tao Jin, Xu Hua'e, Yang Cui, Liu Chun-Na, Li Shengnan
Department of Pharmacology, Nanjing Medical University, Nanjing 210029, China.
Pharmacol Res. 2004 Nov;50(5):471-6. doi: 10.1016/j.phrs.2004.05.006.
The newly isolated peptide, urocortin (UCN) has been found to have potent cardioprotective effects. In order to investigate the effect of UCN on L-type calcium currents (I(Ca,L)), exploring the mechanisms of UCN's cardioprotective effects, we directly measured the I(Ca,L) in the adult rat cardiac myocytes exposed to UCN using standard whole-cell patch-clamp recording technique. Our results showed that UCN exerted decreasing effects on the I(Ca,L) of the single adult rat cardiac myocytes. The current density was inhibited by about 35% after exposure of the cells to UCN (0.1 micromol L(-1)) for 10 min, from the control value of 7.19 +/- 1.44 pA/pF to 4.74 +/- 0.75 pA/pF (n = 5, P < 0.05). This I(Ca,L)-inhibiting action of UCN was concentration dependent. Moreover, no frequency dependence of UCN effects on I(Ca,L) was observed. In combination with previous reports, our results suggest that there might be a close relationship between the cardioprotective effects of UCN and L-type calcium channels.
新分离出的肽——尿皮质素（UCN）已被发现具有强大的心脏保护作用。为了研究UCN对L型钙电流（I(Ca,L)）的影响，探索UCN心脏保护作用的机制，我们使用标准的全细胞膜片钳记录技术，直接测量了暴露于UCN的成年大鼠心肌细胞中的I(Ca,L)。我们的结果表明，UCN对单个成年大鼠心肌细胞的I(Ca,L)有降低作用。将细胞暴露于UCN（0.1微摩尔/升）10分钟后，电流密度从对照值7.19±1.44皮安/皮法抑制到4.74±0.75皮安/皮法（n = 5，P < 0.05），约被抑制35%。UCN的这种I(Ca,L)抑制作用呈浓度依赖性。此外，未观察到UCN对I(Ca,L)的作用有频率依赖性。结合先前的报道，我们的结果表明UCN的心脏保护作用与L型钙通道之间可能存在密切关系。
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