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Signal processing at olivocochlear neuron

橄榄耳蜗神经元的信号处理

基本信息

批准号：
08680888
负责人：
KOYANO Konomi
金额：
$ 1.41万
依托单位：
KYOTO UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1996
资助国家：
日本
起止时间：
1996 至 1997
项目状态：
已结题

项目摘要

The cochlea recieves an efferent innervation from olovocochlear neurons(OC)located in the superior olivary complex OC neurons have been anatomically classified into two groups by their origins and targets ; the lateral and medial OC (LOC and MOC,respectively) neurons. The majority of OC neurons is known to be cholinergic from histochemical investigations. Both groups of OC neurons recieves excitatory voley from afferent auditory tract. Thus, OC neurons form reflex arch to regurate peripheral auditory signal processing Because of the difficulty of their identfication in slice preparation, there were few direct electrophysiological study of OC neurons in spite of their physiological significance. We succeeded to stain living OC neurons by retrograde labeling. Stained OC neurons were identified under a fluorescence microscope and they were sujected to whole-cell recording. LOC and MOC neurons had different electrophysiological properties. When the membrane was slightly hyperpolarized (-72 to -76 mV), LOC neurons showed spike trains with along first interspike interval, whereas MOC neurons showed spike trains with a long latency to the first spike. Under voltage clamp, LOC neurons revealed two transient outward current with different inactivation kinetics. In MOC neurons, there was only one transient outward current. The different expression of these transient outward current between LOC and MOC neurons seems to be responsible for the difference in firing properties of these two groups of neurons.

耳蜗接受来自位于上橄榄复合体的卵耳蜗神经元 (OC) 的传出神经支配 OC 神经元根据其起源和目标在解剖学上分为两类：外侧和内侧 OC（分别为 LOC 和 MOC）神经元。根据组织化学研究，已知大多数 OC 神经元具有胆碱能。两组 OC 神经元均接收来自传入听觉道的兴奋性齐射。因此，OC神经元形成反射弓来调节外周听觉信号处理，由于在切片制备中识别它们的困难，尽管OC神经元具有生理意义，但对其进行直接的电生理学研究却很少。我们成功地通过逆行标记对活的 OC 神经元进行染色。在荧光显微镜下鉴定染色的 OC 神经元，并对它们进行全细胞记录。 LOC和MOC神经元具有不同的电生理特性。当膜轻微超极化（-72 至 -76 mV）时，LOC 神经元显示出具有第一个尖峰间期的尖峰序列，而 MOC 神经元则显示出到第一个尖峰具有较长潜伏期的尖峰序列。在电压钳位下，LOC神经元显示出两种具有不同失活动力学的瞬态外向电流。在 MOC 神经元中，只有一种短暂的外向电流。 LOC 和 MOC 神经元之间这些瞬时外向电流的不同表达似乎是造成这两组神经元放电特性差异的原因。