Department of Neuroscience, Erasmus MC, University Medical Center, 3015 GE Rotterdam, The Netherlands.
Annu Rev Physiol. 2012;74:199-224. doi: 10.1146/annurev-physiol-020911-153236. Epub 2011 Oct 24.
The calyx of Held is an axosomatic terminal in the auditory brainstem that has attracted anatomists because of its giant size and physiologists because of its accessibility to patch-clamp recordings. The calyx allows the principal neurons in the medial nucleus of the trapezoid body (MNTB) to provide inhibition that is both well timed and sustained to many other auditory nuclei. The special adaptations that allow the calyx to drive its principal neuron even when frequencies are high include a large number of release sites with low release probability, a large readily releasable pool, fast presynaptic calcium clearance and little delayed release, a large quantal size, and fast AMPA-type glutamate receptors. The transformation from a synapse that is unremarkable except for its giant size into a fast and reliable auditory relay happens in just a few days. In rodents this transformation is essentially ready when hearing starts.
Held 氏花萼是听觉脑干中的一个轴突体型终末，由于其巨大的体积，吸引了解剖学家的注意；又由于其易于进行膜片钳记录，吸引了生理学家的注意。花萼允许在梯形体内侧核（MNTB）中的主要神经元提供既定时又持续的抑制作用，作用于许多其他听觉核。使花萼即使在高频时也能驱动其主要神经元的特殊适应包括：大量具有低释放概率的释放位点、大的易释放池、快速的突触前钙清除和少量延迟释放、大的量子大小和快速的 AMPA 型谷氨酸受体。从一个除了巨大的体积之外没有什么特别之处的突触转变为快速可靠的听觉中继，只需要短短几天的时间。在啮齿动物中，当听觉开始时，这种转变基本上已经完成。
