Objective Extracellular ATP has been identified as an excitatory neurotransmitter,neuromodulator,or humoral factor which acts via P2 purinoceptors.P2 purinoceptors belong to two major families:a P2X family of ligand-g...
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Objective Extracellular ATP has been identified as an excitatory neurotransmitter,neuromodulator,or humoral factor which acts via P2 purinoceptors.P2 purinoceptors belong to two major families:a P2X family of ligand-gated ion channel receptors and a P2Y family of G protein-coupled *** seven P2X receptor subtypes(P2X1-7) and eight P2Y receptor subtypes(P2Y1,2,4,6,11-14) are *** ATP and P2 purinoceptors play very important roles in the hypothalamo-neurohypophysial *** has been shown that ATP induces a rapid increase in intracellular Ca concentration in the hypothalamic neurosecretory *** injected into paraventricular nucleus (PVN) stimulates the release of vasopressin(VP) from the neurohypophysis via P2 *** has also been presented that multiple P2X receptors are functionally expressed in neurosecretory neurons,at least in those of the supraoptic nucleus(SON).Earlier studies of SON neurons suggested that a P2 receptor-mediated effect of ATP was an intermediate process in VP release evoked by central noradrenergic *** has been shown to excite the neurosecretory VP-containing neurons and the effects were prevented by the P2 receptor antagonist,*** and adrenergic agonists synergize in stimulating VP and OT *** and OT are mainly synthesized in the SON and PVN of the *** studies have demonstrated the distribution of P2X receptors in the SON and PVN of the ***,none of the studies were designed to distinguish different P2 receptor subtypes on VP- and OTcontaining *** Using double-labeling fluorescence immunohistochemistry we have examined the expression of P2X1 -6 receptors and their colocalization with VP or OT in the SON and PVN of the hypothalamus of normal and chronic dehydration *** The results showed that VP-containing neurons expressed P2X2,P2X4,P2X5 and P2X6 receptor and OT-containing neurons expressed P2X2,P2X4 and P2X
目的海马结构内的SGZ（Subgranular zone）是成年哺乳动物脑内两个重要的保留有神经发生的区域之一,其在胚胎脑发生过程中也可能有着重要的作用。在发育过程中,海马结构的位置和形态本身也发生着巨大的变化。本研究旨在阐明人胚胎发育过程中海马结构和SGZ的形成过程及其发生中神经干细胞的分布规律。方法收集胎龄10～32周的水囊引产胎儿25例,分为四个发育阶段:10～12周（n=5）;15～17周（n=8）;22～24周（n=8）和30～32周（n=4）。取含海马结构的颞叶组织做冠状冰冻切片,进行H.E、尼氏和免疫组织化学方法进行染色,对人胎脑海马结构的一般形态、细胞分层和Nestin阳性神经干细胞的分布、形态等进行研究。结果 10～12周海马结构已位于侧脑室下角的底部,呈"C"型,齿状回与海马分界不清楚,但海马结构内细胞呈三个主要细胞层。三层内可见Nestin阳性细胞及突起分布,着色深,细胞圆形或椭圆形。15～17周时,齿状回出现颗粒细胞层,紧紧围绕在门区周围。在海马本部和下托,Nestin阳性细胞主要分布于室床层、多型细胞层和锥体细胞层,室层的阳性细胞胞体体积小,圆形,突起短小,而多型细胞层和锥体细胞层的阳性细胞胞体体积较大,椭圆形或圆形。在VZ、多型细胞层和分子层内可见淡染的波浪状阳性突起向两侧伸展,在齿状回,Nestin阳性细胞分布密集且免疫反应较强主要分布于齿状回的边缘区域。22～24周时,海马结构呈典型的"S"型结构,锥体细胞层和颗粒细胞层明显增厚,Nestin分布的海马各层在形态上明显变薄,齿状回分层明显,Nestin阳性细胞依旧很多,全层分布。30～32周时,海马内Nestin阳性细胞已变得很少,局限在室层,而齿状回内Nestin阳性细胞仍较多,集中分布于颗粒细胞层、紧邻颗粒细胞层的部分分子层和多型细胞层,其中颗粒细胞层与多型细胞层交界处的Nestin阳性细胞最多、密度最大。结论人胎脑海马结构发育过程中,颗粒细胞层出现于15周左右,22～24周时,海马结构呈典型的"S"型结构。随着发育的进行,Nestin阳性细胞的百分比逐次下降,着色减弱。30～32周时Nestin阳性细胞不局限于S G Z。
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