Code R A, Carr C E
Department of Zoology, University of Maryland, College Park 20742-4415, USA.
Hear Res. 1995 Jul;87(1-2):69-83. doi: 10.1016/0378-5955(95)00080-n.
Mammalian lateral olivocochlear (LOC) neurons that are immunoreactive for choline acetyltransferase (ChAT) are also immunoreactive for enkephalin (Enk). To determine whether cochlear efferent neurons in birds might also contain Enk-like immunoreactivity (Enk-LI), we studied the auditory brainstem of the domestic chicken using antisera to ChAT, leucine-enkephalin (L-Enk) and methionine-enkephalin (M-Enk). Enk-LI terminals are found around, but not within, the superior olivary nucleus (SO) and the nucleus of the lateral lemniscus, pars intermedia (LLi). A moderate concentration of Enk-LI terminals is found ventromedial to the ventral facial nucleus (VIIv) where the ventrolateral group of ChAT-I cochlear efferent neurons is located. After colchicine injections into the lateral ventricle, a population of intensely stained Enk-LI perikarya was found in the nucleus of the lateral lemniscus, pars ventralis (LLv) with scattered cells in the LLi and the nucleus subceruleus ventralis (SCv). The distribution of Enk-LI and ChAT-I somata, however, never overlapped, even in adjacent sections. Thus, in the chick, Enk-LI perikarya are not distributed in areas where cochlear efferent neurons are found. Instead, a dense concentration of Enk-I terminals can be found in areas containing ChAT-I cochlear efferent neurons. The source of these enkephalinergic terminals may be a population of Enk-LI cells in the LLv.
对胆碱乙酰转移酶（ChAT）呈免疫反应的哺乳动物外侧橄榄耳蜗（LOC）神经元，对脑啡肽（Enk）也呈免疫反应。为了确定鸟类的耳蜗传出神经元是否也可能含有脑啡肽样免疫反应性（Enk-LI），我们使用针对ChAT、亮氨酸脑啡肽（L-Enk）和甲硫氨酸脑啡肽（M-Enk）的抗血清，研究了家鸡的听觉脑干。在 Superior橄榄核（SO）和外侧丘系核中间部（LLi）周围而非内部发现了Enk-LI终末。在腹侧面神经核（VIIv）腹内侧发现了中等浓度Enk-LI终末，ChAT免疫反应性耳蜗传出神经元的腹外侧组位于此处。向侧脑室注射秋水仙碱后，在外侧丘系核腹侧部（LLv）发现了一群强烈染色的Enk-LI核周体，在LLi和蓝斑腹侧核（SCv）有散在细胞。然而，即使在相邻切片中，Enk-LI和ChAT免疫反应性胞体的分布也从不重叠。因此，在雏鸡中，Enk-LI核周体并不分布在发现耳蜗传出神经元的区域。相反，在含有ChAT免疫反应性耳蜗传出神经元的区域可以发现密集的Enk免疫反应性终末。这些脑啡肽能终末的来源可能是LLv中的一群Enk-LI细胞。
