CHEMORECEPTOR-A-FIBERS IN THE HUMAN CAROTID-BODY CONTAIN TYROSINE-HYDROXYLASE AND NEUROFILAMENT IMMUNOREACTIVITY
CHEMORECEPTOR-A-FIBERS IN THE HUMAN CAROTID-BODY CONTAIN TYROSINE-HYDROXYLASE AND NEUROFILAMENT IMMUNOREACTIVITY
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DOI：
10.1016/0306-4522(92)90179-6
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发表时间：
1992-04-01
期刊：
影响因子：
3.3
通讯作者：
HABECK, JO
中科院分区：
文献类型：
--
作者：
KUMMER, W;HABECK, JO
以往对大鼠和豚鼠的逆行追踪研究表明，感觉酪氨酸羟化酶免疫反应神经元通过颈动脉窦神经投射到颈动脉分叉区。本研究以人颈动脉小体的感觉神经支配为研究对象，应用酪氨酸羟化酶抗血清和其他儿茶酚胺合成酶对尸检获得的颈动脉小体进行了免疫组织化学研究。此外，一系列针对内脏传入神经元中存在的非酶抗原的抗血清也被纳入这项研究。球体小叶由球体细胞和支持细胞组成，含有数量不等的酶免疫反应球体细胞。动脉由神经纤维供应，显示交感去甲肾上腺素能轴突的全部表型，即对酪氨酸羟化酶、芳香族L氨基酸脱羧酶和多巴胺β羟基酶免疫反应。肾小叶密集分布于酪氨酸羟化酶免疫反应轴突，对芳香L氨基酸脱羧酶和多巴胺β羟基酶缺乏免疫反应。这些纤维可与神经丝蛋白160kD抗体反应，但对所有被测神经肽(降钙素基因相关肽、生长抑素、P物质)均无免疫反应。在超微结构上，酪氨酸羟化酶/神经丝蛋白160kD免疫反应阳性轴突引起大量充满线粒体和囊泡的轴突肿胀，并与球体细胞建立了广泛的联系。周围有神经鞘的神经束中既有有髓(直径2.0~2.8mU/m)和无髓(0.14~3.0mU/m)酪氨酸羟化酶免疫反应阳性轴突。大多数无髓鞘免疫反应轴突在雪旺细胞鞘内运行。从免疫反应模式及其终末和终末超微结构判断，支配球体细胞的酪氨酸羟基酶免疫反应轴突是感觉性的。虽然逆行追踪的最终证据不能在人类身上提出，但这一结论得到了实验室动物实验证据的支持。有髓免疫反应轴突与化学受体A纤维相对应，而大的无髓鞘免疫反应轴突的分类尚未建立。这种纤维中缺乏多巴胺合成酶-芳香L氨基酸脱羧酶的免疫反应不支持多巴胺是化学感受器传入的主要递质的观点。
Previous retrograde tracing studies on rat and guinea-pig showed a projection of sensory tyrosine hydroxylase-immunoreactive neurons to the region of the carotid bifurcation via the carotid sinus nerve. In the present study, focussing on the sensory innervation of the human carotid body, antisera to tyrosine hydroxylase and other catecholamine synthesizing enzymes were applied for an immunohistochemical investigation of carotid bodies obtained at autopsy. In addition, an array of antisera directed to non-enzyme antigens known to be present in viscero-afferent neurons were incorporated in the study. The glomic lobules consisting of glomus cells and sustentacular cells contained a variable number of enzyme-immunoreactive glomus cells. Arteries were supplied by nerve fibres displaying the full phenotype of sympathetic noradrenergic axons, i.e. immunoreactivity to tyrosine hydroxylase, aromatic-L-amino-acid-decarboxylase and dopamine-beta-hydroxylase. The glomic lobules, however, were densely innervated by tyrosine hydroxylase-immunoreactive axons lacking immunoreactivity to aromatic-L-amino-acid-decarboxylase and dopamine-beta-hydroxylase. These fibres reacted with neurofilament160kD-antibody but were devoid of immunoreactivity to all neuropeptides tested (calcitonin gene-related peptide, somatostatin, substance P). Ultrastructurally, tyrosine hydroxylase/neurofilament160kD-immunoreactive axons gave rise to large axonal swellings filled with mitochondria and vesicles, and established extensive contacts to glomus cells. Nerve bundles surrounded by a perineural sheath contained both myelinated (2.0-2.8-mu-m in diameter) and unmyelinated (0.14-3.0-mu-m) tyrosine hydroxylase-immunoreactive axons. Most of the unmyelinated immunoreactive axons were running singularly within a Schwann cell-sheath.Judged from the pattern of immunoreactivities as well as their preterminal and terminal ultrastructure, tyrosine hydroxylase-immunoreactive axons innervating glomus cells are of sensory origin. Although final proof by retrograde tracing cannot be presented in man, this conclusion is supported by experimental evidence in laboratory animals. The myelinated immunoreactive axons correspond to chemoreceptor A-fibres whereas the classification of the large unmyelinated immunoreactive axons has yet to be established.The lack of immunoreactivity to the dopamine-synthesizing enzyme, aromatic-L-amino-acid-decarboxylase, in this fibre type does not support the view of dopamine being the primary transmitter of chemoreceptor afferents.