Department of Neurobiology, University of Pittsburgh School of Medicine, Biomedical Science Tower 3, 3501 Fifth Avenue, Pittsburgh, PA 15261, USA.
J Neurosci Methods. 2011 Sep 15;200(2):185-9. doi: 10.1016/j.jneumeth.2011.06.005. Epub 2011 Jun 16.
Simultaneous recordings from connected neuron pairs have brought important insights into synaptic communication between neurons. However, patch clamp recordings from neuron pairs have been largely restricted to brain areas in which connections among nearby neurons exist at a relatively high probability. In the case of more distant connections or in areas in which neurons are connected with low probability, recordings from synaptically connected neuron pairs have remained scarce. Here, we present a method that allows dual recordings from remotely connected neuron pairs by scanning potential presynaptic neurons. The applicability of this new approach was tested in the inhibitory pathway from the medial nucleus of the trapezoid body (MNTB) to the lateral superior olive (LSO), a sound localization pathway in the auditory brainstem. Using a three-step approach that sequentially combines focal uncaging of glutamate, pressure application of glutamate, and loose patch recordings allowed us to reliably achieve recordings from distant, synaptically connected GABA/glycinergic MNTB-LSO neuron pairs. Our results demonstrate that single MNTB neurons evoke highly variable mono-synaptic responses in developing LSO neurons, and heterogeneous short term synaptic dynamics, suggesting local variations in the refinement of these inhibitory connections. Paired recordings, enabled by scanning of remotely connected pairs, will be highly useful to perform detailed investigations of the synaptic function and plasticity from these circuits during the period of developmental refinement. In general, this method should provide a valuable tool to find connected neurons in other brain areas in which recording from candidate pairs has a low success rate.
同时记录连接的神经元对为研究神经元之间的突触通讯提供了重要的见解。然而，从神经元对进行膜片钳记录在很大程度上仅限于那些附近神经元之间存在相对高概率连接的脑区。对于更远距离的连接或神经元以低概率连接的区域，突触连接的神经元对的记录仍然很少。在这里，我们提出了一种通过扫描潜在的突触前神经元来进行远程连接的神经元对双记录的方法。这种新方法的适用性在听觉脑干中的声音定位途径——梯形体中间核（MNTB）到外侧上橄榄核（LSO）的抑制性途径中进行了测试。通过顺序结合焦点光解谷氨酸、谷氨酸加压应用和宽松膜片钳记录的三步方法，我们能够可靠地实现来自远距离、突触连接的 GABA/glycinergic MNTB-LSO 神经元对的记录。我们的结果表明，单个 MNTB 神经元在发育中的 LSO 神经元中引发高度可变的单突触反应和异质的短期突触动力学，表明这些抑制性连接的细化存在局部变化。通过扫描远程连接的神经元对实现的成对记录，对于在发育细化期间研究这些回路的突触功能和可塑性将非常有用。一般来说，这种方法应该为在记录候选对成功率较低的其他脑区中找到连接的神经元提供一个有价值的工具。
