Rat GnRH neurons exhibit large conductance voltage- and Ca2+-activated K+ (BK) currents and express BK channel mRNAs
Rat GnRH neurons exhibit large conductance voltage- and Ca2+-activated K+ (BK) currents and express BK channel mRNAs
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DOI：
10.2170/physiolsci.rp013207
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发表时间：
2008-02-01
影响因子：
2.3
通讯作者：
Kato, Masakatsu
中科院分区：
文献类型：
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作者：
Hiraizumi, Yoshie;Nishimura, Ichiro;Kato, Masakatsu
促性腺激素释放激素（GnRH）神经元形成生殖中枢调节的最终共同通路。与其他神经元一样，动作电位的放电模式对这些神经元正常工作很重要。因此，阐明这些神经元中各种类型离子通道的表达模式非常重要，因为它们决定细胞的兴奋性。迄今为止，电压门控Ca 2+通道和SK通道已被报道在大鼠GnRH神经元中表达。在本研究中，我们专注于K+通道和分析其表达的原代培养的GnRH神经元，制备从GnRH-EGFP转基因大鼠，通过穿孔膜片钳记录。GnRH神经元表现出延迟整流钾电流和大电导电压和钙激活的钾电流。此外，多细胞RT-PCR（逆转录酶-聚合酶链反应）实验揭示了BK通道mRNA（α，β 1，β 2和β 4）的表达。结果表明，延迟整流K+电流和BK电流除了以前报道的慢后超极化电流的存在。这些电流控制动作电位复极，也可能控制放电模式，从而调节GnRH神经元的细胞兴奋性。
Gonadotropin-releasing hormone (GnRH) neurons form the final common pathway for the central regulation of reproduction. As in other neurons, the discharge pattern of action potentials is important for these neurons to function properly. Therefore it is important to elucidate the expression patterns of various types of ion channels in these neurons because they determine cell excitability. To date, voltage-gated Ca2+ channels and SK channels have been reported to be expressed in rat GnRH neurons. In this study, we focused on K+ channels and analyzed their expression in primary cultured GnRH neurons, prepared from GnRH-EGFP transgenic rats, by means of perforated patch-clamp recordings. GnRH neurons exhibited delayed-rectifier K+ currents and large conductance voltage- and Ca2+-activated K+ (BK) currents. Moreover, multicell RT-PCR (reverse transcriptase-polymerase chain reaction) experiments revealed the expression of BK channel mRNAs (alpha, beta 1, beta 2, and beta 4). The results show the presence of delayed-rectifier K+ currents and BK currents besides previously reported slow afterhyperpolarization currents. These currents control the action potential repolarization and probably also the firing pattern, thereby regulating the cell excitability of GnRH neurons.