Reuss Stefan, Disque-Kaiser Ursula, Antoniou-Lipfert Patricia, Gholi Maryam Najaf, Riemann Elke, Riemann Randolf
Department of Anatomy and Cell Biology, School of Medicine, Johannes Gutenberg-University, Mainz, Germany.
Anat Rec (Hoboken). 2009 Apr;292(4):461-71. doi: 10.1002/ar.20881.
The present study was conducted to characterize the superior olivary complex (SOC) of the lower brain stem in the pigmented Djungarian hamster Phodopus sungorus. Using Nissl-stained serial cryostat sections from fresh-frozen brains, we determined the borders of the SOC nuclei. We also identified olivocochlear (OC) neurons by retrograde neuronal tracing upon injection of Fluoro-Gold into the scala tympani. To evaluate the SOC as a putative source of neuronal nitric oxide synthase (nNOS), arginine-vasopressin (AVP), oxytocin (OT), vasoactive intestinal polypeptide (VIP), or pituitary adenylate cyclase-activating polypeptide (PACAP) that were all found in the cochlea, we conducted immunohistochemistry on sections exhibiting retrogradely labeled neurons. We did not observe AVP-, OT-, or VIP-immunoreactivity, neither in OC neurons nor in the SOC at all, revealing that cochlear AVP, OT, and VIP are of nonolivary origin. However, we found nNOS, the enzyme responsible for nitric oxide synthesis in neurons, and PACAP in neuronal perikarya of the SOC. Retrogradely labeled neurons of the lateral olivocochlear (LOC) system in the lateral superior olive did not contain PACAP and were only infrequently nNOS-immunoreactive. In contrast, some shell neurons and some of the medial OC (MOC) system exhibited immunofluorescence for either substance. Our data obtained from the dwarf hamster Phodopus sungorus confirm previous observations that a part of the LOC system is nitrergic. They further demonstrate that the medial olivocochlear system is partly nitrergic and use PACAP as neurotransmitter or modulator.
本研究旨在描述有色毛足田鼠（Phodopus sungorus）脑干下部上橄榄复合体（SOC）的特征。我们使用新鲜冷冻脑的尼氏染色连续低温切片，确定了SOC核的边界。通过向鼓阶注射荧光金进行逆行神经元追踪，我们还鉴定了橄榄耳蜗（OC）神经元。为了评估SOC作为神经元一氧化氮合酶（nNOS）、精氨酸加压素（AVP）、催产素（OT）、血管活性肠肽（VIP）或垂体腺苷酸环化酶激活肽（PACAP）的假定来源，这些物质均在耳蜗中被发现，我们对显示逆行标记神经元的切片进行了免疫组织化学研究。我们在OC神经元或整个SOC中均未观察到AVP、OT或VIP免疫反应性，这表明耳蜗中的AVP、OT和VIP并非起源于橄榄。然而，我们在SOC的神经元胞体中发现了负责神经元一氧化氮合成的酶nNOS和PACAP。外侧上橄榄核中外侧橄榄耳蜗（LOC）系统的逆行标记神经元不含有PACAP，且仅偶尔有nNOS免疫反应性。相比之下，一些壳神经元和一些内侧OC（MOC）系统对这两种物质均表现出免疫荧光。我们从毛足田鼠获得的数据证实了先前的观察结果，即LOC系统的一部分是含氮能的。它们进一步证明内侧橄榄耳蜗系统部分是含氮能的，并使用PACAP作为神经递质或调节剂。
