ACTIVATION OF NICOTINIC ACETYLCHOLINE-RECEPTORS ON CULTURED DROSOPHILA AND OTHER INSECT NEURONS
ACTIVATION OF NICOTINIC ACETYLCHOLINE-RECEPTORS ON CULTURED DROSOPHILA AND OTHER INSECT NEURONS
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DOI：
10.1113/jphysiol.1993.sp019613
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发表时间：
1993-04-01
影响因子：
5.5
通讯作者：
LINGLE, CJ
中科院分区：
文献类型：
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作者：
ALBERT, JL;LINGLE, CJ
1.采用全细胞和单通道记录技术，我们研究了黑腹果蝇（Drosophila melanogaster，果蝇）幼虫和蛹、家蝇（Musca acutitica，家蝇）幼虫和胚胎以及蝗虫（Schistocerca gregaria，蝗虫）若虫神经元乙酰胆碱（Ach）激活电流的特性.在所有的准备工作中，单通道记录揭示了两个主要类别的乙酰胆碱激活通道，平均电导约为32和59 pS.3。在乙酰胆碱浓度从1到10妈妈，在果蝇幼虫神经元通道活动发生在突发平均1-2开口。开放时间和突发持续时间由一个或两个指数描述。32 pS通道的猝发持续时间（约3 ms，慢分量）长于59 pS通道的猝发持续时间（约1.0 ms）。32 pS通道（慢分量）的平均开放间期持续时间也长于59 pS通道。在高乙酰胆碱（20-200妈妈）浓度，突发的较小的电导通道发生在集群分开的长寿命期间没有通道活动。集群之间存在相当大的动力学异质性。全细胞剂量-反应曲线表明，ACh激活电流增加到至少100 μ m，并且涉及多个配体结合步骤。果蝇和家蝇幼虫的神经元乙酰胆碱激活通道在其胆碱能药理学特性方面显示出一些独特的特征：（a）它们仅被有效的神经肌肉烟碱激动剂辛二胆碱弱激活，（B）六甲双铵和十烃双铵是弱的，但近似等效的阻断剂，和（c）α-和κ-银环蛇毒素（BTX）都可逆地阻断，尽管α-BTX似乎是更有效的抑制剂。
1. Using whole-cell and single channel recordings, we have examined the properties of acetylcholine (ACh)-activated currents in neurones from larval and pupal Drosophila melanogaster (fruit fly), larval and embryonic Musca domestica (house fly), and nymphal Schistocerca gregaria (locust).2. In all preparations, single channel recordings revealed two major classes of ACh-activated channels, with average conductances of approximately 32 and 59 pS.3. At ACh concentrations from 1 to 10 mum, channel activity in Drosophila larval neurones occurs in bursts with an average of 1-2 openings. Open times and burst durations are described by one or two exponentials. Burst durations for the 32 pS channel (approximately 3 ms, slow component) were longer than those for the 59 pS channel (approximately 1.0 ms). The mean open interval duration for the 32 pS channel (slow component) was also longer than that of the 59 pS channel.4. At high ACh (20-200 mum) concentrations, bursts of the smaller conductance channel occur in clusters separated by long-lived periods without channel activity. Considerable kinetic heterogeneity was observed among clusters.5. The whole-cell dose-response curve suggests that activation of current by ACh increases up to at least 100 mum and that multiple ligand binding steps are involved.6. Drosophila and Musca larval neuronal ACh-activated channels show some unique features in their cholinergic pharmacological properties: (a) they are only weakly activated by the potent neuromuscular nicotinic agonist suberyldicholine, (b) hexamethonium and decamethonium are weak, but approximately equi-effective blockers, and (c) alpha- and kappa-bungarotoxin (BTX) both blocked reversibly, though alpha-BTX appears to be the more potent inhibitor.