胎儿视皮质皮质下层含─氧化氮合酶神经元的发育

DEVELOPMENT OF THE NITRIC OXIDE SYNTHASE POSITIVE NEURONS IN THE SUBPLATE OF VISUAL CORTEX OF THE HUMAN FETUSES

本文用出生前１７周至３６周胎儿标本１０个，死后４小时内作常规灌注固定，取脑后作视皮质冰冻切片（３０ｕｍ），用一氧化氮合酶（ＮＯＳ）组织化学法孵育切片２～４小时，在视皮质皮质下层（ＳＰ）可见ＮＯＳ强阳性神经元。这些神经元胞体大小不一、形态各异、突起显示呈高尔基染色外观，部分神经纤维含有膨体和生长锥。２０周以后，从ＳＰ层有ＮＯＳ阳性神经纤维伸入皮质板或白质。随着胎龄增长，ＮＯＳ阳性神经元密度增加，胞体切面积增大，神经元由幼稚趋向成熟。本研究还观察到胎儿ＳＰ内ＮＯＳ阳性神经元可从形态上明显地划分为两个阶段，并推测ＮＯＳ合成的一氧化氮（ＮＯ）在突触建立和修饰、突触间信息传递、传入纤维对靶器官的识别和脑组织局部血流调节等过程中起着重要作用。

The nitric oxide synthase(NOS) histochemical technique was used to investigate the subplate(SP) neurons of the visual cortex in 10 human fetuses. he NOS positive neurons could be found in the SP in different shapes and sizes NOS positive processes presented an appearance of Golgi-like staining, and a part of nerve fibers contained knuckles and growth cones. The numerical density and cross sectional areas of the NOS positive neurons increased with the fetal the age. The duration of the development of the NOS positive neuronscan be divided into two stages: neurogenesis and maturity. It has been demonstrated that the thalamic projective axons terminate in the SP before they reach the conical plate. The SP neurons also send axons back to lateral geniculate nucleus (LGN). Form the above study, we suppose that NO produced by NOS may play an impotant role in snaptogenesis and modification, messerger transmission, recongnition of target neurons and local blood supply in the brain during the visual cortex development.