Vasoactive intestinal polypeptide regulates dynamic changes in astrocyte morphometry: Impact on gonadotropin-releasing hormone neurons
Vasoactive intestinal polypeptide regulates dynamic changes in astrocyte morphometry: Impact on gonadotropin-releasing hormone neurons
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DOI：
10.1210/en.2005-1262
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发表时间：
2006-05-01
期刊：
影响因子：
4.8
通讯作者：
Wise, PM
中科院分区：
文献类型：
--
作者：
Gerhold, LM;Wise, PM
最近的研究表明，星形胶质细胞调节GnRH诱导的LH峰。特别是，我们已经表明，表面积的星形胶质细胞的鞘GnRH神经元表现出昼夜节律。血管活性肠多肽（VIP）影响多个脑区星形胶质细胞功能的许多方面，是视交叉上核（SCN）中影响GnRH神经元的神经递质。本研究的目的是：1）评估GnRH神经元周围的星形胶质细胞是否表达VIP受体，2）确定SCN中VIP抑制对GnRH神经元周围星形胶质细胞形态测量学的影响，3）评估这种影响是否模拟星形胶质细胞表面积的衰老样变化。年轻的大鼠卵巢切除术（d 0），植入套管到SCN（d5），注射VIP反义（antioligo）或随机序列寡核苷酸，植入胶囊含有17 β-雌二醇溶解在油（d 7），并在0300，1400和1800小时（d 9）灌注。处理脑用于免疫细胞化学。我们的研究结果表明，星形胶质细胞在密切的贴壁GnRH神经元表达VIP受体。Antioligo处理阻断了星形胶质细胞表面区域的昼夜节律，从而鞘化GnRH神经元。昼夜节律的缺乏类似于中年大鼠的观察结果。总之，这些研究结果表明，在SCN中的VIP神经元的能力，以继电器昼夜信息的GnRH神经元可能是通过影响的动态变化，围绕GnRH神经元的星形胶质细胞的形态。此外，衰老动物中VIP节律的缺乏可能通过星形胶质细胞依赖性机制导致GnRH活性改变。
Recent studies suggest that astrocytes modulate the GnRH-induced LH surge. In particular, we have shown that the surface area of astrocytes that ensheath GnRH neurons exhibits diurnal rhythms. Vasoactive intestinal polypeptide (VIP) influences numerous aspects of astrocyte function in multiple brain regions and is a neurotransmitter in the suprachiasmatic nucleus (SCN) that affects GnRH neurons. The goals of this study were to: 1) assess whether astrocytes that surround GnRH neurons express VIP receptors, 2) determine the effects VIP suppression in the SCN on the morphometry of astrocytes surrounding GnRH neurons, and 3) assess whether this effect mimics aging-like changes in surface area of astrocytes. Young rats were ovariectomized (d0), implanted with cannulae into the SCN (d5), injected with VIP antisense (antioligo) or random sequence oligonucleotides, implanted with capsules containing 17 beta-estradiol dissolved in oil (d 7), and perfused at 0300, 1400, and 1800 h (d 9). Brains were processed for immunocytochemistry. Our results demonstrate that astrocytes in close apposition to GnRH neurons express VIP receptors. Antioligo treatment blocked diurnal rhythms in surface area of astrocytes ensheathing GnRH neurons. The absence of diurnal rhythms resembles observations in middle-aged rats. Together these findings suggest that the ability of the VIP-containing neurons in the SCN to relay diurnal information to GnRH neurons may be by influencing dynamic changes in the morphometry of astrocytes that surround GnRH neurons. Furthermore, the absence of a VIP rhythm in aging animals may lead to altered GnRH activity via astrocyte-dependent mechanisms.