Cowie R J, Carpenter M B
Brain Res. 1985 Dec 9;358(1-2):264-75. doi: 10.1016/0006-8993(85)90970-9.
Transneuronal transport in the auditory system of the squirrel monkey and the arctic ground squirrel was studied after implantation of tritiated protein or glycoprotein precursors into the ampulla of a single semicircular duct. In both species, essentially the same pattern of transneuronal transport extended beyond the cochlear nuclei to the central nucleus of the inferior colliculus (CNIC), after survival periods ranging from 9 to 33 days. Animals displayed dense labeling over nearly all auditory receptors, nearly all portions of the spiral ganglion and throughout the cochlear nuclei (CN). Labeled fibers, mainly in the ventral acoustic stria, terminated over the ipsilateral lateral superior olive (LSO) and the lateral aspect of medial superior olive (MSO). Fibers continuing medially, decussated in an orderly manner, and terminated over the opposite medial nucleus of the trapezoid body (MNTB) and medial aspect of MSO. Labeled fibers projecting into the opposite lateral lemniscus (LL) terminated in the ventral nucleus of the lateral lemniscus (VNLL) and the CNIC. Fibers, but few terminals, were noted over the dorsal nucleus of the LL. The ipsilateral LL contained comparatively few labeled fibers, but sparse terminations occurred over portions of VNLL and CNIC. No transport of [3H]precursors was noted in the peripheral nuclei of the inferior colliculus or in the medial geneculate body on either side. Massive transport via the contralateral LL and the profuse terminals in the opposite CNIC suggested transneuronal transport via secondary and higher order auditory fibers. Although the largest number of fibers in the contralateral LL probably arose from the cochlear nuclei, higher order fibers also may have arisen from the ipsilateral LSO and the contralateral MSO and VNLL. Small numbers of fibers in both species descended from the region of the superior olivary complex (SOC) ventral to the facial motor nucleus. In the ground squirrel, scant auditory projections were traced into the opposite cochlear nuclei. Tritiated precursors in the endolymph passed most readily from labyrinth to cochlea, and transneuronal transport was more extensive in the auditory pathways than in the vestibular system at comparable times. Centrally transported [3H]fucose was cleared more promptly than [3H]proline in monkeys.
将氚标记的蛋白质或糖蛋白前体植入松鼠猴和北极地松鼠单一半规管壶腹后，对其听觉系统中的跨神经元运输进行了研究。在这两个物种中，在9至33天的存活期后，基本上相同的跨神经元运输模式延伸至耳蜗核以外，直至下丘中央核（CNIC）。动物几乎所有听觉感受器、螺旋神经节的几乎所有部分以及整个耳蜗核（CN）都显示出密集标记。标记纤维主要位于腹侧听纹，终止于同侧外侧上橄榄核（LSO）和内侧上橄榄核（MSO）的外侧。继续向内侧走行的纤维有序交叉，并终止于对侧斜方体内侧核（MNTB）和MSO的内侧。投射到对侧外侧丘系（LL）的标记纤维终止于外侧丘系腹侧核（VNLL）和CNIC。在LL背侧核上可见纤维，但终末很少。同侧LL含有的标记纤维相对较少，但在VNLL和CNIC的部分区域有稀疏终末。在下丘外周核或两侧的内侧膝状体中未观察到[3H]前体的运输。通过对侧LL的大量运输以及对侧CNIC中的丰富终末提示跨神经元运输是通过二级及更高级别的听觉纤维进行的。尽管对侧LL中数量最多的纤维可能起源于耳蜗核，但更高级别的纤维也可能起源于同侧LSO以及对侧MSO和VNLL。在这两个物种中，少量纤维从位于面神经运动核腹侧的上橄榄复合体（SOC）区域下行。在北极地松鼠中，追踪到少量听觉投射进入对侧耳蜗核。内淋巴中的氚标记前体最容易从迷路进入耳蜗，并且在可比时间内，听觉通路中的跨神经元运输比前庭系统更广泛。在猴子中，中枢运输的[3H]岩藻糖比[3H]脯氨酸清除得更快。
