CA2+ RELEASE OF LHRH FROM CULTURED LHRH NEURONS FROM EMBRYONIC OLFACTORY PLACODE

目的：探讨钙离子在LHRH释放中的作用。 体外培养。结果在之前的一项研究中，我们已经报告了培养的 猴胚胎嗅觉胎盘来源的LHRH神经元 以脉动的方式将LHRH释放到介质中，大约50分钟 间隔时间。作为研究LHRH脉冲机制的第一步 ，我们研究了钙在LHRH释放中的作用 培养的LHRH神经元。研究结果总结如下：1) 将细胞暴露在低钙(10 NM)缓冲溶液中会受到抑制 2)刺激培养的LHRH细胞释放LHRH 由L类钙通道激动剂Bay K8644(1M)，而它是 被L型钙通道阻滞剂硝苯地平(1M)抑制，但 不是由N型通道阻滞剂w-芋螺毒素(1M)引起的；3) 胞内Ca~(2+)([Ca~(2+)]i)转运ATP酶拮抗剂， Thapsigargin(10M)抑制LHRH释放，而细胞内LHRH释放 钙离子刺激剂兰诺定(1 M)刺激LHRH释放；4) 乙酰-氰化物-对三氟甲氧基苯肼(FCCP，1 mm)，a 线粒体钙激动剂倾向于刺激LHRH的释放。这些 结果表明：1)LHRH的释放受其存在的影响 胞外Ca~(2+)([Ca~(2+)]e)，2)Ca~(2+)通过L型进入细胞内 通道，而不是N型通道；3)[Ca~(2+)]i的动员 对LHRH释放很重要。得出的结论是， [Ca~(2+)]e和Ca~(2+)进入细胞是搏动性LHRH所必需的 在培养的LHRH神经元中释放。此外，[Ca2+]i的动员 似乎有助于LHRH在细胞内的释放。我们的未来方向 将研究LHRH释放是否与[Ca~(2+)]i振荡相关。 关键词LHRH神经元，搏动性，猴胚胎，LHRH释放 体外，细胞内钙离子

OBJECTIVE: To determine the role of Ca2+ in LHRH release in vitro. RESULTS In a previous study we have reported that cultured LHRH neurons derived from the olfactory placode of monkey embryos release LHRH into media in a pulsatile manner at approximately 50-min intervals. As a first step in studying the mechanism of LHRH pulse generation, we examined the role of calcium in LHRH release using cultured LHRH neurons. The results are summarized as follows 1) Exposing the cells to a low Ca2+ (10 nM) buffer solution suppressed LHRH release; 2) LHRH release from cultured LHRH cells was stimulated by the L-type Ca2+ channel stimulant, Bay K 8644 (1 M), while it was suppressed by the L-type Ca2+ channel blocker, nifedipine (1 M), but not by the N-type channel blocker, w-conotoxin (1 M); 3) The intracellular Ca2+ ([Ca2+]i) transporting ATPase antagonist, thapsigargin (10 M), suppressed LHRH release, while the intracellular Ca2+ stimulant, ryanodine (1 M) stimulated LHRH release; 4) Carbonyl-cyanide-P-trifluoromethoxyphenyl hydrazone (FCCP, 1 mM), a mitochondrial Ca2+ mobilizer, tended to stimulate LHRH release. These results indicate that 1) release of LHRH is influenced by the presence of extracellular Ca2+ ([Ca2+]e), 2) Ca2+ enters the cell via L-type channels, but not N-type channels, and 3) mobilization of [Ca2+]i is important for LHRH release. It is concluded that the presence of [Ca2+]e and Ca2+ entry into the cell are essential for pulsatile LHRH release in cultured LHRH neurons. Moreover, mobilization of [Ca2+]i appears to contribute to LHRH release in cells. FUTURE DIRECTIONS We will examine if LHRH release is correlated to [Ca2+]i oscillations. KEY WORDS LHRH neurons, pulsatility, monkey embryos, LHRH release in vitro, intracellular Ca2+