Code R A, Carr C E
Department of Zoology, University of Maryland, College Park 20742-4415.
J Comp Neurol. 1994 Feb 8;340(2):161-73. doi: 10.1002/cne.903400203.
Cholinergic neurons in the chick auditory brainstem were studied with the aid of an antiserum to choline acetyltransferase (ChAT), the biosynthetic enzyme for acetylcholine. ChAT-immunoreactive (ChAT-I) neurons were found in a ventrolateral and a dorsomedial cell group. The ventrolateral group is a rostrocaudally directed column of cells that surround the superior olive (SO), are ventromedial to the ventral facial nucleus (VIIv), and are lateral to the nucleus pontis lateralis (PL) as far rostrally as the nucleus subceruleus ventralis. Cells in the dorsomedial group were found in the pontine reticular formation medial to the dorsal facial nucleus and lateral to the abducens nerve root. Occasionally, small ChAT-I cells were found in the crossed dorsal cochlear tract and in the medial vestibular nucleus near the dorsal border of the caudal nucleus magnocellularis (NM). No ChAT-I neurons or fibers were observed in NM, nucleus angularis, nucleus laminaris, in the nuclei of the lateral lemniscus, or in the nucleus mesencephalicus lateralis pars dorsalis. To determine which cholinergic neurons project to the cochlea, a double-labeling technique was used combining ChAT-I and the retrograde transport of biotinylated dextran amine (BDA) from the inner ear. Double-labeled cells were found bilaterally in both the ventrolateral and dorsomedial cell groups, with the exception of large ChAT-I cells dorsal to the SO, which do not appear to project to the cochlea. Cholinergic cells that project to the cochlea were classified into three morphological groups: multipolar, elongate, and round-to-oval. Both the ventrolateral and the dorsomedial cell groups appear to have a mixture of these different cell types. The average somal area of cholinergic cochlear efferents was 246 microns 2. Only about 70% of the cochlear efferent neurons, however, are cholinergic.
借助针对胆碱乙酰转移酶（ChAT，乙酰胆碱的生物合成酶）的抗血清，对雏鸡听觉脑干中的胆碱能神经元进行了研究。在腹外侧和背内侧细胞群中发现了ChAT免疫反应性（ChAT-I）神经元。腹外侧组是一个前后方向的细胞柱，围绕上橄榄核（SO），位于腹侧面神经核（VIIv）的腹内侧，并且在脑桥外侧核（PL）的外侧，一直延伸到尾侧蓝斑腹侧核。背内侧组的细胞位于背侧面神经核内侧的脑桥网状结构中，以及展神经根的外侧。偶尔，在交叉的背侧耳蜗束和靠近尾侧大细胞性核（NM）背侧边界的内侧前庭核中发现小的ChAT-I细胞。在NM、角状核、层状核、外侧丘系核或中脑外侧核背侧部均未观察到ChAT-I神经元或纤维。为了确定哪些胆碱能神经元投射到耳蜗，采用了一种双重标记技术，将ChAT-I与生物素化葡聚糖胺（BDA）从内耳的逆行运输相结合。在腹外侧和背内侧细胞群中双侧均发现了双重标记的细胞，但SO背侧的大型ChAT-I细胞除外，这些细胞似乎不投射到耳蜗。投射到耳蜗的胆碱能细胞分为三种形态类型：多极、细长和圆形至椭圆形。腹外侧和背内侧细胞群似乎都有这些不同细胞类型的混合。胆碱能耳蜗传出神经元的平均体细胞面积为246平方微米。然而，只有约70%的耳蜗传出神经元是胆碱能的。
