Rodd H D, Loescher A R, Boissonade F M
Department of Child Dental Health, School of Clinical Dentistry, Claremont Crescent, Sheffield, U.K.
Arch Oral Biol. 1998 Jun;43(6):445-54. doi: 10.1016/s0003-9969(98)00025-9.
Characteristics of the pulpal innervation in teeth obtained from a 4-year-old Asian boy with hereditary sensory and autonomic neuropathy, type II (HSAN) were investigated. Four minimally carious primary teeth were split longitudinally and prepared for either fluorescent immunocytochemistry or electron microscopy. The occurrence and distribution of specific neuropeptides were determined by the use of antisera to calcitonin gene-related peptide (CGRP), substance P (SP), neuropeptide Y (NPY), and vasoactive intestinal polypeptide (VIP). The overall innervation of the pulps was visualized using antiserum to protein gene product 9.5; an antiserum to dopamine beta-hydroxylase was used to identify postganglionic sympathetic fibres. Pulpal innervation in HSAN was notably different from that of normal teeth: in comparison with the controls, HSAN teeth had an overall marked reduction in pulpal innervation with an absence of large nerve bundles and the subodontoblastic plexus. CGRP- and SP-immunoreactivity was absent in HSAN specimens and VIP-immunoreactivity was reduced. However, NPY-immunoreactivity appeared to be increased within certain regions of the pulp/dentine complex. In addition, there was evidence of NPY-immunoreactive fibres extending into dentine, a feature not seen in the controls. Electron microscopy revealed an absence of myelinated nerve fibres and a paucity of unmyelinated fibres. CGRP and SP have a well-established role in nociceptive processing and their absence in the HSAN teeth would seem to correspond with the clinical presentation of marked peripheral sensory deficit, characteristic of this condition. An up-regulation of NPY-immunoreactivity has previously been reported in animal teeth following nerve injury and a similar mechanism may have stimulated increased NPY expression in HSAN teeth, but the functional significance of its presence within dentinal nerves is not known.
对一名患有遗传性感觉和自主神经病变II型（HSAN）的4岁亚洲男孩的牙齿牙髓神经支配特征进行了研究。将四颗轻度龋坏的乳牙纵向劈开，制备用于荧光免疫细胞化学或电子显微镜检查的样本。通过使用降钙素基因相关肽（CGRP）、P物质（SP）、神经肽Y（NPY）和血管活性肠多肽（VIP）的抗血清来确定特定神经肽的出现和分布。使用针对蛋白质基因产物9.5的抗血清来观察牙髓的整体神经支配；使用针对多巴胺β-羟化酶的抗血清来识别节后交感神经纤维。HSAN牙髓的神经支配与正常牙齿明显不同：与对照组相比，HSAN牙齿的牙髓神经支配总体上显著减少，没有大的神经束和成牙本质细胞下丛。HSAN样本中不存在CGRP和SP免疫反应性，VIP免疫反应性降低。然而，NPY免疫反应性在牙髓/牙本质复合体的某些区域似乎增加。此外，有证据表明NPY免疫反应性纤维延伸到牙本质中，这一特征在对照组中未见。电子显微镜显示无髓神经纤维缺失，无髓纤维稀少。CGRP和SP在伤害性感受处理中具有既定作用，它们在HSAN牙齿中的缺失似乎与这种疾病特有的明显外周感觉缺陷的临床表现相符。先前在动物牙齿神经损伤后报道了NPY免疫反应性上调，类似的机制可能刺激了HSAN牙齿中NPY表达增加，但其在牙本质神经中的功能意义尚不清楚。
