Trimarchi J R, Murphey R K
Department of Biology, Molecular and Cellular Biology Program, Morrill Science Center, University of Massachusetts, Amherst, Massachusetts 01003, USA.
J Neurosci. 1997 Jun 15;17(12):4700-10. doi: 10.1523/JNEUROSCI.17-12-04700.1997.
The shaking-B2 mutation was used to analyze synapses between haltere afferents and a flight motoneuron in adult Drosophila. We show that the electrical synapses among many neurons in the flight circuit are disrupted in shaking-B2 flies, suggesting that shaking-B expression is required for electrical synapses throughout the nervous system. In wild-type flies haltere afferents are dye-coupled to the first basalar motoneuron, and stimulation of these afferents evokes electromyograms from the first basalar muscle with short latencies. In shaking-B2 flies dye coupling between haltere afferents and the motoneuron is abolished, and afferent stimulation evokes electromyograms at abnormally long latencies. Intracellular recordings from the motoneuron confirm that the site of the defect in shaking-B2 flies is at the synapses between haltere afferents and the flight motoneuron. The nicotinic cholinergic antagonist mecamylamine blocks the haltere-to-flight motoneuron synapses in shaking-B2 flies but does not block those synapses in wild-type flies. Together, these results show that the haltere-to-flight motoneuron synapses comprise an electrical component that requires shaking-B and a chemical component that is likely to be cholinergic.
利用颤抖 - B2突变体来分析成年果蝇中平衡棒传入神经元与飞行运动神经元之间的突触。我们发现，在颤抖 - B2果蝇中，飞行回路中许多神经元之间的电突触受到破坏，这表明在整个神经系统中电突触的形成需要颤抖 - B的表达。在野生型果蝇中，平衡棒传入神经元与第一基底运动神经元染料偶联，刺激这些传入神经元会在短潜伏期内诱发第一基底肌的肌电图。在颤抖 - B2果蝇中，平衡棒传入神经元与运动神经元之间的染料偶联被消除，传入刺激诱发肌电图的潜伏期异常延长。对运动神经元的细胞内记录证实，颤抖 - B2果蝇的缺陷位点位于平衡棒传入神经元与飞行运动神经元之间的突触处。烟碱型胆碱能拮抗剂美加明阻断了颤抖 - B2果蝇中从平衡棒到飞行运动神经元的突触，但不阻断野生型果蝇中的那些突触。这些结果共同表明，从平衡棒到飞行运动神经元的突触包括一个需要颤抖 - B的电突触成分和一个可能是胆碱能的化学突触成分。
