In vitro models for the effects of sex hormones on neurons.
In vitro models for the effects of sex hormones on neurons.
复制标题
性激素对神经元影响的体外模型。
DOI：
10.1111/j.1749-6632.1996.tb16251.x
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发表时间：
1996
影响因子：
5.2
通讯作者：
Lustig,RH
中科院分区：
文献类型：
--
作者：
Lustig,RH
尽管构成哺乳动物大脑的数十亿个神经元数量众多，种类繁多，但它们在发育过程中有能力组织形成特定的细胞群和纤维束，这些细胞群和纤维束在同一物种的个体之间几乎没有变化。因此，大脑的生长和组织是生物系统中模式形成的一个例子。在其他器官系统中，模式的形成受到细胞间接触或连接的影响。相反，神经元间连接的建立本身就是正常脑个体发育的目标。这些模式对于不同的脑核和区域的发育和整合是必不可少的，这些区域构成了大脑的高级功能。由于这个原因，神经元知道何时与谁形成连接的方式是现代神经生物学的一个基本问题。神经元间的连接主要由突触和间隙连接组成，通过神经元突起之间的特殊接触而发生。突触发生在一个神经元的传入轴突和另一个神经元的传出树突之间，而间隙连接发生在两个神经元的树突之间。因此，任何可以改变树突或轴突发育、形态或过程生长的过程都可能改变zyxwutz体内神经元间连通性的模式。理解脑模式形成调控过程的一个有用策略是比较不同人群中神经元数量或形态、突触或间隙连接数量或频率系统性不同的大脑区域。性激素依赖性神经组织就是这样一个系统。人类神经系统的几个区域已被证明在男性和女性之间存在差异。同样，啮齿类动物边缘系统的许多区域已被证明是有性的，尽管尚未得到证实，但人们认为这些神经解剖学上的差异解释了认知、行为和生殖生理学上的性别差异。此外，在动物模型中，出生前和出生前的性激素环境决定了神经元间连接的模式。这些区域，如大鼠的性二态核（SDN）和腹内侧下丘脑（VMH），在神经发育早期是统一的，但围产期性激素环境导致了不同的产后发育。这些激素诱导的神经解剖学上的性别差异可能是成年后高级脑功能的功能性性别差异的基础。这些发现还表明，在性激素反应神经元中，雌激素和雄激素可能对突触和间隙连接的形成以及树突和轴突的发育有影响。zyxwvutsrqponm
Despite their number and diversity, the several billion neurons that comprise the mammalian brain have the ability to organize during development to form specific cell groups and fiber tracts that vary little among individuals of the same species. Thus, the growth and organization of the brain is an example of pattern formation in a biological system.'In other organ systems, pattern formation is influenced by intercellular contact or connections. In contrast, the establishment of interneuronal connections is itself the goal of normal brain ontogeny. These patterns are essential to the development and integration of distinct brain nuclei and regions that constitute seats of higher brain function. For this reason, the manner by which neurons know when and with whom zyxwvutsrqpo to form connections is a fundamental issue in modern neurobiology. Interneuronal connections occur via specialized contacts between their neuritic processes and consist primarily of synapses and gap junctions. Synapses occur between the afferent axon of one neuron and the efferent dendrite of a second neuron, while gap junctions occur between dendrites of two neurons. Thus, any process that can alter either dendrite or axon development, morphology, or process outgrowth is likely to alter the pattern of interneuronal connectivity in zyxwvutsrqponm vivo.One useful strategy for understanding the regulatory processes of brain pattern formation is to compare brain areas in which neuronal numbers or morphology, or synapse or gap junction number or frequency, is systematically different among populations. One such system is that of sex hormone-dependent neural organization. Several areas of the human nervous system have been shown to differ between males and female^.^-^ Similarly, many areas of the limbic system of rodent species have been shown to be sexually Although not proven, it is thought that these neuroanatomic differences account for sex differences in cognition, behavior, and reproductive physiology. Furthermore, in animal models, the sex hormonal milieu present before and during birth dictates the pattern of interneuronal connectivity. These areas, such as the sexually dimorphic nucleus (SDN) and ventromedial hypothalamus (VMH) of the rat, are unimorphic early in neural development, but the perinatal sex hormone milieu causes divergent postnatal development. These hormone-induced neuroanatomic sex dimorphisms likely underlie functional sex differences in higher brain function in adulthood. l3-l7 These findings also imply that, within sex hormone-responsive neurons, estrogen andlor androgen may have effects on synapse andlor gap junction formation and on dendrite and axon development. zyxwvutsrqponm