Rodríguez-Contreras Adrián, van Hoeve John Silvio Soria, Habets Ron L P, Locher Heiko, Borst J Gerard G
Department of Neuroscience, Erasmus MC, University Medical Center Rotterdam, Dr. Molewaterplein 50, 3015 GE Rotterdam, The Netherlands.
Proc Natl Acad Sci U S A. 2008 Apr 8;105(14):5603-8. doi: 10.1073/pnas.0801395105. Epub 2008 Mar 28.
The calyx of Held is probably the largest synaptic terminal in the brain, forming a unique one-to-one connection in the auditory ventral brainstem. During early development, calyces have many collaterals, whose function is unknown. Using electrophysiological recordings and fast-calcium imaging in brain slices, we demonstrate that these collaterals are involved in synaptic transmission. We show evidence that the collaterals are pruned and that the pruning already begins 1 week before the onset of hearing. Using two-photon microscopy to image the calyx of Held in neonate rats, we report evidence that both axons and nascent calyces are structurally dynamic, showing the formation, elimination, extension, or retraction of up to 65% of their collaterals within 1 hour. The observed dynamic behavior of axons may add flexibility in the choice of postsynaptic partners and thereby contribute to ensuring that each principal cell eventually is contacted by a single calyx of Held.
Held 壶腹可能是大脑中最大的突触终末，在听觉腹侧脑干中形成独特的一对一连接。在早期发育过程中，壶腹有许多侧支，其功能尚不清楚。我们利用脑片的电生理记录和快速钙成像技术证明，这些侧支参与突触传递。我们有证据表明侧支会被修剪，且修剪在听力开始前 1 周就已开始。利用双光子显微镜对新生大鼠的 Held 壶腹进行成像，我们报告有证据表明轴突和新生壶腹在结构上是动态的，在 1 小时内其侧支多达 65%会出现形成、消除、延伸或回缩。观察到的轴突动态行为可能会增加突触后伙伴选择的灵活性，从而有助于确保每个主细胞最终仅与一个 Held 壶腹接触。
