DESENSITIZATION OF EMBRYONIC NICOTINIC ACETYLCHOLINE-RECEPTORS EXPRESSED IN XENOPUS OOCYTES
DESENSITIZATION OF EMBRYONIC NICOTINIC ACETYLCHOLINE-RECEPTORS EXPRESSED IN XENOPUS OOCYTES
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DOI：
10.1016/0304-3940(93)90487-6
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发表时间：
1993-04-02
影响因子：
2.5
通讯作者：
DUDEL, J
中科院分区：
文献类型：
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作者：
BUFLER, J;FRANKE, C;DUDEL, J
向非洲爪蟾卵母细胞注射编码牛烟碱型乙酰胆碱受体（nAChR）胚胎型的mRNA。利用液丝开关将乙酰胆碱（ACh）脉冲施加于注射后的卵母细胞的外面向外式膜片上。在高浓度ACh（10⁻³ M）时，ACh反应迅速脱敏；其衰减可用时间常数约为50毫秒的单指数函数拟合。在双脉冲实验中，对脱敏后的恢复情况进行了测试。5秒后观察到完全恢复。通过用不同浓度的ACh对外面向外式膜片进行预孵育来测量ACh对脱敏受体的亲和力。用10⁻⁶ M ACh预孵育导致膜片上的nAChR完全脱敏。这些结果可以用最近为小鼠肌肉胚胎型nAChR建立的描述nAChR激活和脱敏的分子机制来拟合。
Xenopus oocytes where injected with mRNA coding for the embryonic type of the bovine nicotinic acetylcholine receptor (nAChR). Pulses of actylcholine (ACh) were applied to outside-out patches of the injected oocytes with the liquid filament switch. With high concentrations of ACh (10(-3) M), the ACh response desensitized rapidly; the decay could be fitted with a single exponential with a time constant of about 50 ms. In double pulse experiments, recovery from desensitization was tested. Complete recovery was observed after 5 s. The affinity of ACh to the desensitized receptor was measured by preincubating the outside-out patch with different concentrations of ACh. Preincubation with 10(-6) M ACh led to complete desensitization of the nAChRs on the patch. The results can be fitted with the molecular scheme describing activation and desensitization of the nAChR which was developed recently for embryonic nAChRs of mouse muscle.