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  

Modulations of the high-voltage sensitive Ca^(2+) channels by GTP and GDP analogues in the central neurons of cotton bollworm (Helicoverpa armigera)

作　　者：李杰[1] 佟帆[1] 贺秉军[1] 胡兆农[2] 刘安西[1] 

机构地区：[1]南开大学生命科学学院,天津300071 [2]西北农林科技大学农药研究所,陕西杨凌712100

出　　处：《昆虫学报》2005年第1期31-35,共5页Acta Entomologica Sinica

基　　金：国家自然科学基金资助项目 (3 0 2 70 884)

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 2 0min。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 2 0min时降为初始值的 (72 0 9± 12 80 ) %。电极内液中加入 2mmol LGTPγS可缓解电流的衰减现象 ,在第 2 0min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 0 1) ,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 2mmol LGDPβS则导致峰电流衰减更加严重 ,第 2 0min时 ,峰电流仅为初始水平的 (41 95± 9 32 ) % ,显著小于对照组(P <0 0 1) ,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。Using Ba^(2+) as current carrier, the effect of G proteins on the high-voltage sensitive Ca^(2+) 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 GTPγS shifted to the positive voltage. In contrast, guanosine 5'-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.

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 

分 类 号：Q965[生物学—昆虫学]