高亲和性的神经营养因子受体TrkB和TrkC免疫阳性神经元在人脑干内的分布

HIGH-AFINITY NEUROTROPHIN RECEPTOR TrkB AND TrkC IMMUNOREACTIVE NEURONS IN THE BRAINSTEM IN HUMANS

用免疫组化方法对６例人脑干神经营养因子高亲和受体ｔｒｋＢ和ｔｒｋＣ的分布进行了研究．证明ｔｒｋＢ和ｔｒｋＣ阳性胞体和突起广泛分布于脑干不同区域．除ｔｒｋＣ含膨体的轴突较多、分布较ｔｒｋＢ为广外，两者分布模式基本一致．脑桥及下橄榄核含ｔｒｋＢ和ｔｒｋＣ强阳性神经元；脑神经运动核及部分感觉核含两者的中等或较强神经元。上、下丘，大脑脚背盖，中缝核，网状核也含有两者的阳性神经元．黑质及蓝斑区色素细胞内仅见很淡的两者阳性产物．但黑质网状部的非黑色素神经元则为中等或强阳性．黑质、脚间核、脑桥和下橄榄核合有两者的强阳性纤维，其他区域神经毯呈中等度阳性。在分布模式及染色强度上未见年龄差别．以上结果表明两者在人脑干内广泛且有选。择性地分布，说明神经营养因子３在成年及老年脑干神经通路中具有调节作用．

We have described the detailed distribution of trkB and trkC-immunoreactive (-ir) neurons in the human brainstem, using immunohistochemistry with antibodies that recognize specifically the full-Iength trkB andtrkC, respectively. Human brains, obtained at autopsy from 6 neurologically normal patients aged from 47 to 88years, were fixed by perfusion with formaldehyde fixative through cerebral arteries. Brainstems were cut and imunohistochemistry was carried out on serial sections. TrkB and trkC-ir neurons and neuronal processes were present widely throughout the brainstem, with differential regional distributions. The patterns between trkB-ir andtrkC-ir were similar, except that trkC-ir varicose axons were more numerous and widespread than trkB-ir ones.The pontine and inferior olivary nuclei contained intensively labelled cell bodies and neuropil for both trkB andtrkC. Moderate intensity of trkB and trkC-immunoreactivities were found in neurons of all cranial motor and somesensory nuclei (the mesencephalic trigeminal, principal trigeminal, dorsal column nuclei). Subgroups of neuronspositive for either trkB or trkC were present in superior and inferior colliculi, pedunculopontine tegmental, raphe,and reticular nuclei. Faint labelling of trkB or trkC was observed in the melanin-pigment containing neurons of thesubstantia nigra and locus ceoruleus, though non-melanin pigmented neurons of the substantia nigra were positivefor trkB and trkC. Intensive trkB and trkC-ir neuropil was seen in the substantia nigra, interpeduncular, pontineand inferior olivary nuclei. Moderate intensity of neuropil staining of both irk proteins was found in widespread regions. No apparent age differences were observed in regional pattern or cellular distribution of both trk proteins.Our results indicate a widespread but selective distribution of full-length trkB and trkC proteins in the humanbrainstem, suggesting that brain-derived neurotrophic factor and neurotrophin-3 may play a role in regulating neuronal circuitry in mature human brainstem.