GnRH suppresses excitability of visual processing neurons in the optic tectum.
GnRH suppresses excitability of visual processing neurons in the optic tectum.
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DOI：
10.1152/jn.00710.2015
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发表时间：
2015-09
影响因子：
2.5
通讯作者：
Chie Umatani;Ryosuke Misu;S. Oishi;K. Yamaguchi;H. Abe;Y. Oka
中科院分区：
文献类型：
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作者：
Chie Umatani;Ryosuke Misu;S. Oishi;K. Yamaguchi;H. Abe;Y. Oka
动物会根据环境中的感官线索以及生理状态改变其行为。例如，人们普遍认为，它们的性行为是根据季节性环境变化或个体的成熟/生殖状态进行调节的，并且神经肽在这一过程中发挥了重要作用。一些行为调制来自中枢神经系统中感觉信息处理的神经肽调制，但神经机制仍然未知。在这里，我们集中在脊椎动物的视觉加工的神经肽调制的神经基础。含有促性腺激素释放激素3（TN-GnRH 3）的终末神经元被认为调节生殖行为，并有大量投射到视顶盖（OT），在视觉处理中起重要作用。在本研究中，研究是否GnRH 3调节视网膜顶盖神经传递的OT，我们分析了GnRH 3的电生理和形态学的影响。我们发现，场电位引起的视束纤维刺激，这代表视网膜顶盖神经传递，调制突触后GnRH 3。视网膜-顶盖通路中突触后神经元的全细胞记录表明，GnRH 3激活大电导Ca（2+）激活的K（+）（BK）通道，从而抑制膜兴奋性。此外，我们使用荧光标记的GnRH肽改进的形态学分析表明，GnRH受体主要定位于突触后神经元的细胞体周围。我们的研究结果表明，TN-GnRH 3神经元调节视网膜-顶盖神经传递抑制投射神经元的兴奋性在OT，这是神经肽GnRH 3的行为相关的视觉信息处理的神经调节的基础。
Animals change their behavior in response to sensory cues in the environment as well as their physiological status. For example, it is generally accepted that their sexual behavior is modulated according to seasonal environmental changes or the individual's maturational/reproductive status, and neuropeptides have been suggested to play important roles in this process. Some behavioral modulation arises from neuropeptide modulation of sensory information processing in the central nervous system, but the neural mechanisms still remain unknown. Here we focused on the neural basis of neuropeptide modulation of visual processing in vertebrates. The terminal nerve neurons that contain gonadotropin-releasing hormone 3 (TN-GnRH3 neurons) are suggested to modulate reproductive behavior and have massive projections to the optic tectum (OT), which plays an important role in visual processing. In the present study, to examine whether GnRH3 modulates retino-tectal neurotransmission in the OT, we analyzed the effect of GnRH3 electrophysiologically and morphologically. We found that field potentials evoked by optic tract fiber stimulation, which represent retino-tectal neurotransmission, were modulated postsynaptically by GnRH3. Whole cell recording from postsynaptic neurons in the retino-tectal pathway suggested that GnRH3 activates large-conductance Ca(2+)-activated K(+) (BK) channels and thereby suppresses membrane excitability. Furthermore, our improved morphological analysis using fluorescently labeled GnRH peptides showed that GnRH receptors are localized mainly around the cell bodies of postsynaptic neurons. Our results indicate that TN-GnRH3 neurons modulate retino-tectal neurotransmission by suppressing the excitability of projection neurons in the OT, which underlies the neuromodulation of behaviorally relevant visual information processing by the neuropeptide GnRH3.