Milner T A, Joh T H, Pickel V M
J Neurosci. 1986 Sep;6(9):2585-603. doi: 10.1523/JNEUROSCI.06-09-02585.1986.
We sought to determine the ultrastructural localization and the extrinsic sources of the catecholamine-synthesizing enzyme, tyrosine hydroxylase (TH), in the lateral parabrachial region (PBR) of adult male rats. In the first portion of the study, a rabbit antiserum to TH was immunocytochemically localized in coronal sections through the lateral PBR from acrolein-fixed brains using the peroxidase-antiperoxidase method. Electron-microscopic analysis revealed that perikarya and dendrites with peroxidase immunoreactivity for TH constituted only 17% of the total labeled profiles. Afferents to the TH-labeled perikarya and dendrites usually failed to exhibit immunoreactivity and were thus considered noncatecholaminergic. Somatic synapses were most commonly detected on small immunoreactive perikarya in the central lateral nucleus of the PBR. Other labeled perikarya located in the dorsal lateral or ventral lateral nuclei received few somatic synapses and were morphologically distinct in terms of their larger size, infolded nuclear membrane, and abundance of cytoplasmic organelles. Axons and axon terminals with peroxidase immunoreactivity constituted the remaining labeled profiles in the lateral PBR. These terminals primarily formed symmetric synapses with unlabeled and a few labeled dendrites. The labeled axon terminals were categorized into 2 types: Type I was small (0.3-0.6 micron), contained many small clear vesicles, and exhibited few well-defined synaptic densities. The second type was large (0.8-1.4 micron), contained both small clear and large dense core vesicles, and exhibited well-defined synaptic densities. The 2 types of terminals were morphologically similar to dopaminergic terminals. The location of catecholaminergic neurons contributing to the TH-labeled terminals was determined by combining peroxidase-antiperoxidase immunocytochemistry for TH with retrograde transport of wheat germ agglutinin-conjugated horseradish peroxidase (WGA-HRP). The tracer was unilaterally injected into the PBR of anesthetized adult rats. Immunocytochemical labeling for TH was seen as a brown reaction product within neurons in known catecholaminergic cell groups. A black granular reaction product formed by a cobalt-intensified and diaminobenzidine-stabilized tetramethyl benzidine reaction for WGA-HRP was evident within many TH-labeled and unlabeled neurons.(ABSTRACT TRUNCATED AT 400 WORDS)
我们试图确定成年雄性大鼠外侧臂旁核（PBR）中儿茶酚胺合成酶酪氨酸羟化酶（TH）的超微结构定位及其外在来源。在研究的第一部分，使用过氧化物酶-抗过氧化物酶方法，将兔抗TH血清免疫细胞化学定位在丙烯醛固定脑的外侧PBR冠状切片中。电子显微镜分析显示，对TH具有过氧化物酶免疫反应性的胞体和树突仅占总标记轮廓的17%。TH标记的胞体和树突的传入纤维通常不显示免疫反应性，因此被认为是非儿茶酚胺能的。在PBR中央外侧核的小免疫反应性胞体上最常检测到体突触。位于背外侧或腹外侧核的其他标记胞体接受的体突触很少，并且在形态上有所不同，它们更大、核膜折叠且细胞质细胞器丰富。具有过氧化物酶免疫反应性的轴突和轴突终末构成了外侧PBR中其余的标记轮廓。这些终末主要与未标记和少数标记的树突形成对称突触。标记的轴突终末分为2种类型：I型小（0.3 - 0.6微米），含有许多小清亮囊泡，且显示出很少明确的突触小体；第二种类型大（0.8 - 1.4微米），含有小清亮囊泡和大致密核心囊泡，且显示出明确的突触小体。这2种类型的终末在形态上与多巴胺能终末相似。通过将TH的过氧化物酶-抗过氧化物酶免疫细胞化学与小麦胚凝集素结合辣根过氧化物酶（WGA-HRP）的逆行运输相结合，确定了对TH标记终末有贡献的儿茶酚胺能神经元的位置。将示踪剂单侧注入麻醉成年大鼠的PBR。在已知的儿茶酚胺能细胞群的神经元内，TH的免疫细胞化学标记表现为棕色反应产物。在许多TH标记和未标记的神经元内，由WGA-HRP的钴增强和二氨基联苯胺稳定的四甲基联苯胺反应形成的黑色颗粒反应产物很明显。（摘要截断于400字）
