人胎视皮质皮质下层NPY－IR神经元的发育

本文用免疫组化方法研究了１６周至足月人胎视皮质皮质下层ＮＰＹ－ＩＲ神经元的发育。各胎龄视皮质ＳＰ层内均有ＮＰＹ－ＩＲ神经元分布。从１６周至２６周，ＮＰＹ－ＩＲ神经元密度逐渐增高并于２６周达高峰；３２周以后阳性神经元密度随胎龄增长而下降。人胎视皮质ＳＰ层ＮＰＹ－ＩＲ神经元形态也随胎龄而变化；２０周以前，ＮＰＹ－ＩＲ神经元大多是胞体较小，突起短而少的未分化神经元、ＳＰ层内ＮＰＹ－ＩＲ纤维少。２０周以后，ＮＰＹ－ＩＲ神经元胞体增大，突起增多、变长；多极和双极、双簇神经元随胎龄增长而增多；ＳＰ层内的ＮＰＹ－ＩＲ纤维大量增加，部分纤维穿入皮质板。３２周以后，多极ＮＰＹ－ＩＲ神经元逐渐减少，双极双簇神经元所占比例相对增高。ＮＰＹ免疫组化结合ＮＡＤＰＨ－ｄ组化显示人胎视皮质ＳＰ层大多数ＮＰＹ－ＩＲ神经元同时呈ＮＯＳ阳性。本研究观察到人胎视皮质ＳＰ层内ＮＰＹ－ＩＲ神经元发育可分为发生、成熟和退化三个阶段。

DEVELOPMENT OF NPY-IR NEURONS IN THE SUBPLATE OF VISUAL CORTEX OF THE HUMAN FETUSES

Development of NPY-- immunoreactive (NPY--IR) neurons in the subplate (SP) of primary visual cortex (VC) of human fetuses aged from 16 weeks to full term was studied immunohistochemically. NPY--IR neurons were distributed in the SP of the VC of all age fetuses. The numerical density of NPY--IR neurons in SP of VC increased from 16w to 26w andpeaked at about 26w, but declined after 32w. The morphology of the NPY--IR neurons in SPof VC was changing during development. Before 20 weeks, most NPY--IR neurons werewithout process or unipolar, and poorly stained. A few N13Y--IR fibres located in SP. After20 weeks, most NPY--IR neurons were the multipolar, bipolar or bituted in shape which usually had a large somata with complex dendrite--like processes. NPY--IR fibres' in the SP increased markedly, and ran in different directions, some penetrated into the conical plate (C.P. ) After 32w, ac,ost multipolar NPY--IR neuron diminished gradually, leading the percentage of the bipolar of bitufted neurons being highest. It has been shown that most SPY--IRneurons were also NOS-- positive by the study combining immunohistochemistry withNADPH-- d histocaemistry The presert study indicates the prenatal development of NPY--IRSP neurons in human visual cortex undergoes three stages, e. g, neurogenesis, maturationand regression stages.