爪蟾视觉发育过程中抑制性GABAa受体功能的变化(英文)  

Variation of mIPSCs mediated by GABAa receptors during visual development in Xenopus

作　　者：王红[1] 温小红[1] 蔡浩然[1] 

机构地区：[1]北京大学第一医院中心实验室,北京100034

出　　处：《中国神经科学杂志》2003年第4期216-222,共7页

基　　金：国家自然科学基金 ( 3 9670 774);中国教育部基金资助~~

摘　　要：目的 :阐明从幼年 (变态脱尾后 2～ 12周 )到成年 (变态脱尾后 5～ 10月 )爪蟾的视顶盖神经元突触受体变化。 方法 :盲法脑片全细胞电压钳技术。结果 :成年视顶盖神经元的微抑制性突触后电流 (mIPSCs)的发放频率 (Hz)和平均振幅 (pA)分别为 2 .6 5± 0 .6 9和 9.82± 1.30 ,而幼年的分别为 0 .6 8± 0 .2 3和 15 .36± 2 .4 0 ,其中成年动物的mIPSCs的频率是幼年频率的 3.90倍 ;乙酰胆碱受体 (nAChR)激动剂carbachol均可使幼年及成年的mIPSCs频率增加 ,增强效率有所不同 ,幼年增加至对照组的 192 .0 % ,而成年组仅为 14 6 .2 %。 结论 :随着视顶盖神经元的成熟 ,其突触GABAa受体功能也相应增强。Objective: To characterize the receptors located in the presynaptic and postsynaptic membranes of tectal neurons in juvenile (2 to 12 weeks post metamorphosis) and adult (5～10 months post metamorphosis) Xenopus . Methods: Using the blind technique, whole cell patch clamp recordings were made from layer VI of a slice preparation of the Xenopus optic tectum in vitro . Results: The mIPSCs recorded from the tectal neurons in the adult Xenopus ( n =57) and in the juvenile ( n =32) were completely abolished by bath application of the GABAa antagonist bicuculline. The frequency of mIPSCs recorded from the adult Xenopus (2.65 Hz±0.69 Hz) was 3.90 fold higher than that of the juvenile animals (0.68 Hz±0.23 Hz), but the averaged amplitude of the former (9.82 pA±1.30 pA) was smaller than that of the latter (15.36 pA±2.40 pA).The mIPSCs were modulated presynaptically by nACh receptors. nAChR agonists such as carbachol could induce an enhancement in the mIPSC frequency. The enhancement of mIPSC frequency induced by carbachol in juvenile Xenopus (192.0 % of control) was stronger than that in older animals (146.2% of control). Conclusion: With the maturation of tectal neuron, the functional GABAa receptors increased progressively. \[

关 键 词：爪蟾 视觉发育 GABAA 受体功能 视顶盖 神经元 突触受体 电压钳 

分 类 号：Q43[生物学—生理学]