β-endorphin alters electrical activity of gonadotropin releasing hormone neurons located in the terminal nerve of the teleost medaka (Oryzias latipes)
β-endorphin alters electrical activity of gonadotropin releasing hormone neurons located in the terminal nerve of the teleost medaka (Oryzias latipes)
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DOI：
10.1016/j.ygcen.2006.07.004
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发表时间：
2007-01-01
影响因子：
2.7
通讯作者：
Kuwahara, Kenrick
中科院分区：
文献类型：
--
作者：
Wayne, Nancy L.;Kuwahara, Kenrick
内源性阿片肽（EOPs）是下丘脑-垂体轴的一类重要调节剂;阿片类药物治疗可抑制GnRH和LH分泌，抑制生殖功能。然而，很少有人研究阿片类药物对GnRH神经元电活动的影响，而GnRH神经元最终控制GnRH分泌。本研究的目的是探讨EOP β-内啡肽对位于嗅球相关终末神经（TN）的GnRH神经元电活动的影响。我们使用了一个切除的完整的大脑制备转基因青鳉，其中绿色荧光蛋白（GFP）的基因表达在TN-GnRH神经元。然后将这些表达GFP的神经元靶向用于全细胞电流钳记录。治疗β-内啡肽导致的变化，在几个特征的电活动，包括去极化的膜电位和减少尖峰振幅类似于观察到的响应去极化高K+治疗。这一发现表明了一种模型，其中β-内啡肽使膜电位去极化，导致Na+通道失活，随后抑制动作电位振幅。另一方面，β-内啡肽对突触分离的GnRH神经元的膜电位没有影响。这些结果表明，β-内啡肽间接作用于TN-GnRH神经元，抑制动作电位放电。(c)2006爱思唯尔公司All rights reserved.
Endogenous opioid peptides (EOPs) are an important class of modulators of the hypothalamo-pituitary axis; treatment with opiates leads to inhibition of GnRH and LH secretion and suppression of reproductive functions. However, little work has been done to investigate the effect of opiates on the electrical activity of GnRH neurons, which ultimately controls GnRH secretion. The purpose of the present study was to investigate the effects of the EOP beta-endorphin on electrical activity of GnRH neurons located in the terminal nerve (TN) associated with the olfactory bulb. We used an excised intact brain preparation from transgenic medaka in which green fluorescent protein (GFP) is genetically expressed in TN-GnRH neurons. These GFP-expressing neurons were then targeted for whole-cell current clamp recordings. Treatment with beta-endorphin led to changes in several characteristics of electrical activity, including depolarization of membrane potential and a decrease in spike amplitude-similar to that observed in response to depolarizing high K+ treatment. This finding suggests a model in which beta-endorphin depolarizes membrane potential leading to Na+-channel inactivation, and subsequent suppression of action-potential amplitude. On the other hand, beta-endorphin had no effect on membrane potential in synaptically isolated GnRH neurons. These results suggest that beta-endorphin is acting indirectly on TN-GnRH neurons to inhibit action potential firing. (c) 2006 Elsevier Inc. All rights reserved.