Structural and functional differences distinguish principal from nonprincipal cells in the guinea pig MSO slice.
Structural and functional differences distinguish principal from nonprincipal cells in the guinea pig MSO slice.
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结构和功能差异区分了豚鼠 MSO 切片中的主要细胞和非主要细胞。
DOI：
10.1152/jn.1995.73.4.1653
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发表时间：
1995
期刊：
影响因子：
--
通讯作者：
Smith,PH
中科院分区：
文献类型：
--
作者：
Smith,PH
1.内侧上级橄榄（MSO）中的主细胞通过左右耳蜗核接收来自双耳的低频信息。在体内细胞外记录表明，一些MSO神经元最佳响应时，双耳声信号有一个精确的耳间延迟。因此，MSO细胞，特别是主细胞，被认为是处理耳间时间差线索的第一阶段，该线索提供关于低频声音在空间中的位置的信息。2.尽管提出了MSO的基本作用，但该细胞核的某些特征使得很难获得任何细胞类型的体内记录。文献中只报道了少量的细胞外记录，没有细胞内记录。使用尖锐的，神经生物素填充的玻璃电极记录细胞内从细胞在体外脑切片的豚鼠上级橄榄复合体，我已经开始评估的解剖和生理功能的细胞中的MSO可能是相关的，这样的功能在体内的作用。3.两种基本的MSO细胞类型，指定的主要和非主要，可以区分的基础上，某些解剖和生理差异。4.标记的主细胞体位于MSO内的所有背腹侧位置。标记的非主细胞位于或周围的背侧方面的核。主细胞通常有厚的双极树突（1个指向内侧，1个指向外侧），除了在其末端外，没有明显的锥形或分支。非主细胞是多极的3至9个较薄的初级树突，没有分支优先在内侧方向。主细胞轴突发出终止于背侧MSO及其周围的侧枝。背侧MSO内及周围的非主细胞也有轴突。非主细胞也有支配背侧MSO的轴突侧支，但这些轴突可以更广泛地分支，并进一步向下投射到核的背腹侧。5.主细胞通常对去极化电流脉冲作出反应，在电流开始时具有一个或几个尖峰。当浸泡在含有4-氨基吡啶（4-AP）的盐水中时，它们重复发射相同的去极化电流脉冲。这将表明去极化诱导的非线性类似于在其他两个听觉脑干核，前腹侧耳蜗核和斜方体内侧核的主要细胞类型中看到的。非主要细胞通常反复发射去极化电流脉冲，甚至接近尖峰阈值。两种细胞类型都可以显示出超极化电流脉冲的膜电位下降。（400字处截断摘要）
1. Principal cells in the medial superior olive (MSO) receive low-frequency information from both ears via left and right cochlear nuclei. In vivo extracellular records suggest that some MSO neurons respond optimally only when the binaural acoustic signal has a precise interaural delay. Thus MSO cells, in particular principal cells, are thought to be the first stage in the processing of interaural time difference cues that provides information as to the location of a low-frequency sound in space. 2. Despite this proposed fundamental role for the MSO, certain features of this nucleus make in vivo recordings from any cell type here very difficult to obtain. Only a small number of extracellular records and no intracellular recordings are reported in the literature. Using sharp, neurobiotin-filled glass electrodes to record intracellularly from cells in an in vitro brain slice of the guinea pig superior olivary complex, I have begun to assess the anatomic and physiological features of cells in the MSO that might be relevant to such a functional role in vivo. 3. Two basic MSO cell types, designated principal and nonprincipal, could be distinguished on the basis of certain anatomic and physiological differences. 4. Labeled principal cell bodies were located at all dorsoventral location within the MSO. Labeled nonprincipal cells were located in or around the dorsal aspects of the nucleus. Principal cells typically had thick bipolar dendrites (1 directed medially, 1 laterally) that did not taper or branch significantly except at their terminations. Nonprincipal cells were multipolar with three to nine thinner primary dendrites that did not branch preferentially in a mediolateral direction. Principal cell axons gave off collaterals terminating in and around the dorsal MSO. Nonprincipal cells also had axon in and around the dorsal MSO. Nonprincipal cells also had axon collateral branches innervating dorsal MSO, but these axons could branch more extensively and project further down the dorsoventral aspect of the nucleus. 5. Principal cells typically responded to depolarizing current pulses with one or a few spikes at current onset. When bathed in saline containing 4-aminopyridine (4-AP), they fired repetitively to the same depolarizing current pulses. This would indicate a depolarization-induced nonlinearity similar to that seen in principal cell types of two other auditory brain stem nuclei, the anteroventral cochlear nucleus and medial nucleus of the trapezoid body. Nonprincipal cells normally fired repetitively to depolarizing current pulses even close to spike threshold. Both cell types could show a sag in the membrane potential to hyperpolarizing current pulses.(ABSTRACT TRUNCATED AT 400 WORDS)