›› 2005, Vol. 48 ›› Issue (1): 31-35.

• 研究论文 • 上一篇    下一篇

GTP和GDP类似物对棉铃虫神经细胞高电压敏感钙通道的调节作用

李杰1, 佟帆1, 贺秉军1, 胡兆农2, 刘安西1   

  • 出版日期:2005-03-20 发布日期:2005-02-20

Modulations of the high_voltage sensitive Ca2+ channels by GTP and GDP analogues in the central neurons of cotton bollworm (Helicoverpa armigera)

LI Jie1, TONG Fan1, HE Bing-Jun1, HU Zhao-Nong2, LIU An-Xi1   

  • Online:2005-03-20 Published:2005-02-20

摘要: 以Ba2+为载流子,采用全细胞膜片钳法,研究了在电极液中分别加入G蛋白稳定 激活剂GTPγS(GTP类似物)和抑制剂GDPβS(GDP类似物)对棉铃虫Helicoverpaarmigera 3龄幼虫神经细胞高电压敏感钙通道的调节作用。Ba2+电流记录时间为20 min。对照组 和实验组的Ba2+电流在记录的初期均出现电流的增加现象,随后电流衰减,即“rundown ”。对照组峰电流在第20 min时降为初始值的(72.09±12.80)%。电极内液中加入2 mmol/L GTPγS可缓解电流的衰减现象,在第20 min时,峰电流为初始值的(95.99±7.93)%,明显大 于对照组的峰电流(P<0.01),而且电流电压(I-V)关系曲线向正电压方向移动。相反 ,电极内液加入2 mmol/L GDPβS则导致峰电流衰减更加严重,第20 min时,峰电流仅为初始水 平的(41.95±9.32)%,显著小于对照组(P<0.01),但未见电流电压(I-V)关系曲 线的明显漂移。结果表明,棉铃虫神经细胞钙通道活动受G蛋白激活剂GTPγS和G蛋白抑制剂GDPβS的影响,提示G蛋白活动水平的改变调节钙通道的电流幅值和电压依赖性。

关键词: 棉铃虫, GTP类似物, GDP类似物, 高电压敏感钙通道, 膜片钳

Abstract: Using Ba2+as current carrier, the effect of G proteins on the highvoltage sensitive Ca2+ channels in the central neurons isolated from the 3rd instar larvae of the cotton bollworm Helicoverpa armigera was studied with the whole cell patch clamp technique. The results indicated that the inclusion of guanosine 5'-O-(3-thiotriposate) (GTPγS, 2 mmol/L) in the pipette solution prevented the decline in peak current, and (95.99±7.93)% of the initial current was remained by the end of 20 min recording, compared with (72.09±12.80)% in the control (P <0.01). Moreover, I-V relationship curve obtained from neurons treated with GTP Γs shifted to the positive voltage. In contrast, guanosine5 '-O-(2- thiophosphate) (GDPβS, 2 mmol/L) in the intracellular solution reduced the peak current to (41.95±9.32)% of the initial value, significantly lower than that in the control (P<0.01). No obvious shift of the I-V relationship curve was caused by GDPβS. The results showed that the activities of calcium channels were influenced by GTPγS and GDPβS, which suggests that current amplitude and voltage dependence of calcium channels in H. armigera are modulated by G proteins.

Key words: Helicoverpa armigera, GTP analogue, GDP analogue, highvoltage sensitive, calcium channel, patch clamp 