异戊酸对非洲爪蟾蝌蚪的制动作用及其相关机制

Immobilization of tadpoles with isovaleric acid and related mechanism

目的观察异戊酸对非洲爪蟾蝌蚪运动的影响,探讨异戊酸对非洲爪蟾卵母细胞膜上甘氨酸耦联的抑制性氯离子通道的影响及其与异戊酸麻醉样作用的关系。方法对非洲爪蟾的蝌蚪在体观察异戊酸的制动效应;采用微注射法使非洲爪蟾卵母细胞上过度表达α1甘氨酸受体,并通过双电极电压钳技术测量异戊酸对甘氨酸耦联的抑制性氯离子通道功能的影响。结果异戊酸在非洲爪蟾蝌蚪中可产生类麻醉效应,其EC50为(44.8±3.7)mmol/L;Hill系数为4.1±1.2;浓度为5.0、7.5、10、20mmol/L的异戊酸可明显增强甘氨酸诱发的氯离子通道电流强度,增强程度为(19.4±4.9)%、(78.6±5.6)%、(107±27)%、(187±39)%,有显著性差异(P<0.01)。异戊酸可呈浓度依赖性地增加通过非洲爪蟾卵母细胞上甘氨酸耦联抑制性氯离子通道的电流。结论异戊酸对非洲爪蟾蝌蚪具有制动作用,其机制可能与增强对甘氨酸耦联抑制性氯离子通道的电流有关。

Objective To observe the immobilization effect of isovaleric acid on tadpoles. To investigate the role of glycine receptor in the anesthetic effect of isovaleric acid. Methods Anesthetic potency of isovaleric acid was tested in 7-10 days old tadpoles by exposing the tadpoles to isovaleric acid solution and prodding on the side of the tadpoles. Glycine receptors were over-expressed on the Xenopus laevis oocytes and voltage clamping was employed to measure the change of inflow currency through the chloride ion channel on the oocyte membrane during the administration of isovaleric acid solution. Results Isovaleric acid showed dose-dependent immobilization effect in Xenopus laevis tadpoles and the anesthetic ED50 was 44.8±3.7mmol/L. A significant increase of chloride ion inflow was noticed in Xenopus laevis oocytes with the application of isovaleric acid in a dose-dependent manner. Conclusions Isovaleric acid has anesthetic effect in animal. The enhancement on the inhibitory glycine recept or might contribute to the anesthetic-like effect of isovaleric acid.