Arvanov V, Usherwood P N
Department of Zoology, University of Nottingham, U.K.
Neurosci Lett. 1991 Apr 15;125(1):9-11. doi: 10.1016/0304-3940(91)90116-b.
Xenopus oocytes injected with rat brain RNA were voltage-clamped using a 2-electrode technique. At 4-10 days post-injection the oocytes responded to applications of 10(-6) M to 10(-4) M gamma-aminobutyric acid (GABA), L-kainate and L-glutamate. All 3 compounds evoked inward currents. At 10(-4) ouabain alone evoked an inward current of 4-6 nA at -60 mV, but had no effect on membrane conductivity (ca. 5 microS). In ouabain-containing saline the responses to GABA, L-kainate and L-glutamate were increased by 80-120%, 20-30% and 20-40%, respectively, in both folliculated and defolliculated oocytes. These changes were not accompanied by shifts in the reversal potentials for the agonist-induced membrane currents. At 10(-4) M ouabain also increased oocyte weight and volume. It is proposed that ouabain, by increasing oocyte volume, increases the area of oocyte membrane containing receptors which is accessible to exogenously applied compounds.
使用双电极技术对注射了大鼠脑RNA的非洲爪蟾卵母细胞进行电压钳制。在注射后4 - 10天，卵母细胞对10⁻⁶M至10⁻⁴M的γ-氨基丁酸（GABA）、L- kainate和L-谷氨酸的施加有反应。所有这三种化合物都诱发内向电流。在10⁻⁴M哇巴因单独作用时，在 - 60mV下诱发4 - 6nA的内向电流，但对膜电导率（约5微西门子）没有影响。在含有哇巴因的盐溶液中，无论是有卵泡的还是去卵泡的卵母细胞，对GABA、L- kainate和L-谷氨酸的反应分别增加了80 - 120%、20 - 30%和20 - 40%。这些变化并没有伴随着激动剂诱导的膜电流的反转电位的改变。在10⁻⁴M时，哇巴因还增加了卵母细胞的重量和体积。有人提出，哇巴因通过增加卵母细胞体积，增加了含有可被外源性施加的化合物作用的受体的卵母细胞膜面积。
