Department of Neurology and Division of Otolaryngology & Dentistry, Department of Surgery, University of Toledo College of Medicine and Life Sciences, Toledo, OH, USA.
Department of Neurology and Division of Otolaryngology & Dentistry, Department of Surgery, University of Toledo College of Medicine and Life Sciences, Toledo, OH, USA.
Hear Res. 2018 Dec;370:264-271. doi: 10.1016/j.heares.2018.08.008. Epub 2018 Aug 25.
There is evidence for a function of acetylcholine in the cochlear nucleus, primarily in a feedback, modulatory effect on auditory processing. Using a microdissection and quantitative microassay approach, choline acetyltransferase activity was mapped in the trapezoid bodies of rats, in which the activity is relatively higher than in cats or hamsters. Maps of series of sections through the trapezoid body demonstrated generally higher choline acetyltransferase activity rostrally than caudally, particularly in its portion ventral to the medial part of the spinal trigeminal tract. In the lateral part of the trapezoid body, near the cochlear nucleus, activities tended to be higher in more superficial portions than in deeper portions. Calculation of choline acetyltransferase activity in the total trapezoid body cross-section of a rat with a comprehensive trapezoid body map gave a value 3-4 times that estimated for the centrifugal labyrinthine bundle, which is mostly composed of the olivocochlear bundle, in the same rat. Comparisons with other rats suggest that the ratio may not usually be this high, but it is still consistent with our previous results suggesting that the centrifugal cholinergic innervation of the rat cochlear nucleus reaching it via a trapezoid body route is much higher than that reaching it via branches from the olivocochlear bundle. The higher choline acetyltransferase activity rostrally than caudally in the trapezoid body is consistent with evidence that the centrifugal cholinergic innervation of the cochlear nucleus derives predominantly from locations at or rostral to its anterior part, in the superior olivary complex and pontomesencephalic tegmentum.
有证据表明乙酰胆碱在耳蜗核中有功能，主要是在听觉处理的反馈调节作用。使用微切割和定量微分析方法，在大鼠的梯形体内绘制了胆碱乙酰转移酶活性图，其中活性相对高于猫或仓鼠。通过一系列穿过梯形体的切片图表明，胆碱乙酰转移酶活性通常在头侧比尾侧更高，特别是在靠近三叉神经脊髓束内侧部分的腹侧部分。在靠近耳蜗核的梯形体外侧部分，活动倾向于在较浅部分比在较深部分更高。根据综合梯形体图谱计算大鼠整个梯形体横截面积中的胆碱乙酰转移酶活性，得到的值是同一大鼠离心迷路束（主要由橄榄耳蜗束组成）估计值的 3-4 倍。与其他大鼠的比较表明，该比值通常不会这么高，但仍与我们之前的结果一致，即大鼠耳蜗核的离心胆碱能支配通过梯形体途径到达耳蜗核的程度要高于通过橄榄耳蜗束分支到达的程度。梯形体头侧比尾侧的胆碱乙酰转移酶活性更高，这与证据一致，即耳蜗核的离心胆碱能支配主要来自其前部或前部的位置，在橄榄上核复合体和桥脑被盖。
