Neuromodulatory Effect of GnRH on the Synaptic Transmission of the Olfactory Bulbar Neural Circuit in Goldfish, Carassius auratus
Neuromodulatory Effect of GnRH on the Synaptic Transmission of the Olfactory Bulbar Neural Circuit in Goldfish, Carassius auratus
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DOI：
10.1152/jn.00639.2010
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发表时间：
2010-12-01
影响因子：
2.5
通讯作者：
Oka, Yoshitaka
中科院分区：
文献类型：
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作者：
Kawai, Takafumi;Abe, Hideki;Oka, Yoshitaka
Kawai T, Abe H, Akazome Y, Oka Y. GnRH对金鱼嗅球神经回路突触传递的神经调节作用。中国生物医学工程学报，2009,31(2):559 - 559。首次发表于2010年10月20日；doi: 10.1152 / jn.00639.2010。促性腺激素释放激素（GnRH）是一种众所周知的促性腺激素，产生于下丘脑，促进垂体促性腺激素的释放。另一方面，下丘脑外GnRH系统的功能仍然难以捉摸。在这里，我们研究了嗅球神经回路的活动是否受到主要来自金鱼（Carassius auratus）末梢神经（TN） GnRH系统的GnRH的调节。作为形态学基础，我们首先观察到金鱼TNs主要表达鲑鱼GnRH (sGnRH) mRNA，并且sGnRH免疫反应纤维分布在二尖瓣层和颗粒细胞层。然后，我们通过细胞外记录检查了GnRH对二尖瓣细胞到颗粒细胞突触活动引起的体外电诱发场电位的影响。我们发现GnRH增强了场电位的振幅。此外，在两种情况下，分别通过刺激外侧或内侧嗅道来激发场电位，分别传递功能不同的感觉信息时，观察到这些影响，并表明GnRH可能调节嗅球对各种气味的反应。由于GnRH也改变了配对脉冲比，因此提示场电位振幅的增加是由于二尖瓣细胞突触前谷氨酸释放的变化，而不是颗粒细胞谷氨酸受体敏感性的增加。这些结果表明，TN通过在嗅球神经回路中释放sGnRH肽来调节动物的嗅觉反应性。
Kawai T, Abe H, Akazome Y, Oka Y. Neuromodulatory effect of GnRH on the synaptic transmission of the olfactory bulbar neural circuit in goldfish, Carassius auratus. J Neurophysiol 104: 3540-3550, 2010. First published October 20, 2010; doi:10.1152/jn.00639.2010. Gonadotropin-releasing hormone (GnRH) is well known as a hypophysiotropic hormone that is produced in the hypothalamus and facilitates the release of gonadotropins from the pituitary gonadotropes. On the other hand, the functions of extrahypothalamic GnRH systems still remain elusive. Here we examined whether the activity of the olfactory bulbar neural circuits is modulated by GnRH that originates mainly from the terminal nerve (TN) GnRH system in goldfish (Carassius auratus). As the morphological basis, we first observed that goldfish TNs mainly express salmon GnRH (sGnRH) mRNA and that sGnRH-immunoreactive fibers are distributed in both the mitral and the granule cell layers. We then examined by extracellular recordings the effect of GnRH on the electrically evoked in vitro field potentials that arise from synaptic activities from mitral to granule cells. We found that GnRH enhances the amplitude of the field potentials. Furthermore, these effects were observed in both cases when the field potentials were evoked by stimulating either the lateral or the medial olfactory tract, conveying functionally different sensory information, separately, and suggesting that GnRH may modulate the responsiveness to wide categories of odorants in the olfactory bulb. Because GnRH also changed the paired-pulse ratio, it is suggested that the increased amplitude of the field potential results from changes in the presynaptic glutamate release of mitral cells rather than the increase in the glutamate receptor sensitivity of granule cells. These results suggest that TN regulates the olfactory responsiveness of animals appropriately by releasing sGnRH peptides in the olfactory bulbar neural circuits.