A study to clarify the role of postsynaptic cells in synaptic plasticity by using double patch clamp method.

我们利用由同一神经元支配的两个肌肉组成的系统，研究了突触后CaMKII在果蝇神经肌肉连接处突触发育中的作用。CaMKII的活性可以通过GAL4-UAS表达系统在两条肌肉中的一条或两条肌肉中进行调控。同时用双膜片钳法记录相邻的突触后肌细胞的反应。这似乎是一种独特的方法来检测突触后变化的特定影响。我们发现，CaMKII的突触后激活以突触特异性的方式促进新孵化的幼虫突触前和突触后位点的协调成熟。我们还发现，在孵化后约7小时的老年幼虫中，其促进作用有所减弱。另一方面，CaMKII活性未被操纵的肌肉细胞突触在老年幼虫中受到影响。这些结果表明，CaMKII的作用在突触发育过程中发生了变化，突触修饰从一个突触到另一个突触的传播只在突触发育到一定阶段后才出现。

We have been studying the role of postsynaptic CaMKII during development of synapses at Drosophila neuromuscular junctions by using the system which consists of two muscles innervated by the same neurons. Activity of CaMKII can be manipulated in one of the two muscles or both muscles by GAL4-UAS expression system. We simultaneously recorded the response of those adjacent postsynaptic muscle cells by the double-patch clamp method. This seems to be a unique way to detect the specific effect of postsynaptic changes. We have found that postsynaptic activation of CaMKII promotes coordinated maturation of pre- and postsynaptic sites of newly hatched larvae in a synapse-specific manner. We also showed that its promotive effects were reduced in the older larvae which were about 7 hrs after hatching. On the other hand, synapses on the muscle cell in which CaMKII activity was not manipulated were affected in the older larvae. These results suggest that the action of CaMKII changes during synaptic development and the propagation of synaptic modification from-one synapse to the other appear only after a certain developmental stage of synapses.