High expression of the R-type voltage-gated Ca2+ channel and its involvement in Ca2+-dependent gonadotropin-releasing hormone release in GT1-7 cells.
High expression of the R-type voltage-gated Ca2+ channel and its involvement in Ca2+-dependent gonadotropin-releasing hormone release in GT1-7 cells.
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DOI：
10.1210/en.2003-1257
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发表时间：
2004-05
期刊：
影响因子：
4.8
通讯作者：
Miho Watanabe;Y. Sakuma;Masakatsu Kato
中科院分区：
文献类型：
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作者：
Miho Watanabe;Y. Sakuma;Masakatsu Kato
GT 1细胞已被广泛用作研究GnRH神经元的细胞功能的模型细胞。尽管Ca（2+）通道的重要性，但除了在GT 1细胞中的L型和T型Ca（2+）通道外，对Ca（2+）通道知之甚少。因此，我们采用膜片钳技术和RT-PCR技术研究了GT 1 -7细胞电压门控性Ca（2+）通道的多样性。R型Ca（2+）通道阻断剂SNX-482对所有检测的细胞（n = 9）的Ca（2+）电流的抑制率为75.6%。T型Ca（2+）通道阻断剂Ni（2+）可使Ca（2+）电流抑制12.6%（n = 9）。L-型Ca（2+）通道阻断剂尼莫地平（Nimodipine）对11个细胞中的5个细胞的Ca（2+）电流有17.9%的抑制作用。当使用Ba（2+）作为电荷载体时，另一种二氢吡啶拮抗剂硝苯地平在所有检查的细胞中（n = 16）明显抑制电流12.1%。N型Ca（2+）通道阻滞剂omega-conotoxin-GVIA在检查的20个细胞中的3个中抑制Ca（2+）电流13.8%。P/Q型Ca（2+）通道阻断剂omega-agatoxin-IVA对电流无影响（n = 9）。RT-PCR显示GT 1 -7细胞表达α（1B）、α（1D）、α（1 E）和α（1H）亚基mRNA。此外，SNX-482和硝苯地平抑制高K（+）诱导的细胞内Ca（2+）浓度升高和GnRH释放。ω-芋螺毒素-GVIA和ω-龙舌兰毒素-IVA没有影响。这些结果表明，GT 1 -7细胞表达R型、L型、N型和T型电压门控性Ca（2+）通道; R型是主要的电流成分，L型、N型和T型是次要的。R型和L型Ca（2+）通道在Ca（2+）依赖性GnRH释放的调节中起关键作用。
The GT1 cell has been widely used as a model cell to study cellular functions of GnRH neurons. Despite the importance of Ca(2+) channels, little is known except for L- and T-type Ca(2+) channels in GT1 cells. Therefore, we studied the diversity of voltage-gated Ca(2+) channels in GT1-7 cells with perforated-patch clamp and RT-PCR. An R-type Ca(2+) channel blocker, SNX-482, inhibited the Ca(2+) currents by 75.6% in all cells examined (n = 9). A T-type Ca(2+) channel blocker, Ni(2+), inhibited the Ca(2+) currents by 12.6% in all cells examined (n = 9). An L-type Ca(2+) channel blocker, nimodipine, inhibited the Ca(2+) currents by 17.9% in five of 11 cells examined. When using Ba(2+) as a charge carrier, another dihydropyridine antagonist, nifedipine, clearly inhibited the currents by 12.1% in all cells examined (n = 16). An N-type Ca(2+) channel blocker, omega-conotoxin-GVIA, inhibited the Ca(2+) currents by 13.8% in three of 20 cells examined. A P/Q type Ca(2+) channel blocker, omega-agatoxin-IVA, had no effect on the currents (n = 9). RT-PCR revealed that GT1-7 cells expressed the alpha(1B), alpha(1D), alpha(1E), and alpha(1H) subunit mRNA. Furthermore, SNX-482 and nifedipine inhibited the high K(+)-induced increase in the intracellular Ca(2+) concentration and GnRH release. omega-Conotoxin-GVIA and omega-agatoxin-IVA had no effect. These results suggest that GT1-7 cells express R-, L-, N-, and T-type voltage-gated Ca(2+) channels; the R-type was a major current component, and the L-, N-, and T-types were minor ones. The R- and L-type Ca(2+) channels play a critical role in the regulation of Ca(2+)-dependent GnRH release.