Institute of Neurobiology, University of Puerto Rico, Medical Sciences Campus, San Juan, Puerto Rico.
Department of Anatomy & Neurobiology, University of Puerto Rico, Medical Sciences Campus, San Juan, Puerto Rico.
PLoS One. 2021 Nov 30;16(11):e0260553. doi: 10.1371/journal.pone.0260553. eCollection 2021.
The Drosophila NMJ is a system of choice for investigating the mechanisms underlying the structural and functional modifications evoked during activity-dependent synaptic plasticity. Because fly genetics allows considerable versatility, many strategies can be employed to elicit this activity. Here, we compare three different stimulation methods for eliciting activity-dependent changes in structure and function at the Drosophila NMJ. We find that the method using patterned stimulations driven by a K+-rich solution creates robust structural modifications but reduces muscle viability, as assessed by resting potential and membrane resistance. We argue that, using this method, electrophysiological studies that consider the frequency of events, rather than their amplitude, are the only reliable studies. We contrast these results with the expression of CsChrimson channels and red-light stimulation at the NMJ, as well as with the expression of TRPA channels and temperature stimulation. With both these methods we observed reliable modifications of synaptic structures and consistent changes in electrophysiological properties. Indeed, we observed a rapid appearance of immature boutons that lack postsynaptic differentiation, and a potentiation of spontaneous neurotransmission frequency. Surprisingly, a patterned application of temperature changes alone is sufficient to provoke both structural and functional plasticity. In this context, temperature-dependent TRPA channel activation induces additional structural plasticity but no further increase in the frequency of spontaneous neurotransmission, suggesting an uncoupling of these mechanisms.
果蝇 NMJ 是研究活动依赖性突触可塑性过程中结构和功能修饰的机制的首选系统。由于果蝇遗传学具有很大的灵活性，因此可以采用许多策略来引发这种活动。在这里，我们比较了三种不同的刺激方法，以在果蝇 NMJ 上引发结构和功能的活动依赖性变化。我们发现，使用富含 K+的溶液驱动的模式刺激方法可产生强大的结构修饰，但会降低肌肉活力，这可以通过静息电位和膜电阻来评估。我们认为，使用这种方法，考虑事件频率而不是幅度的电生理研究才是唯一可靠的研究。我们将这些结果与 NMJ 处 CsChrimson 通道和红光刺激的表达以及 TRPA 通道和温度刺激的表达进行了对比。对于这两种方法，我们都观察到了可靠的突触结构修饰和一致的电生理特性变化。实际上，我们观察到缺乏突触后分化的不成熟突触及自发神经传递频率的增强。令人惊讶的是，单独施加温度变化的模式足以引发结构和功能可塑性。在这种情况下，温度依赖性 TRPA 通道激活会引起额外的结构可塑性，但不会增加自发神经传递的频率，表明这些机制已经解耦。
