Capacitation of mouse sperm is modulated by gamma-aminobutyric acid (GABA) concentration
Capacitation of mouse sperm is modulated by gamma-aminobutyric acid (GABA) concentration
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DOI：
10.1262/jrd.2019-008
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发表时间：
2019-08-01
影响因子：
1.8
通讯作者：
Tanemura, Kentaro
中科院分区：
文献类型：
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作者：
Kurata, Shouhei;Hiradate, Yuuki;Tanemura, Kentaro
在哺乳动物中，射出的精子在通过雌性生殖道的迁移过程中获得它们的可吸收性，这分泌了几种有助于精子获能的因子。γ-氨基丁酸（GABA）是中枢神经系统中的一种众所周知的神经递质，但也能增强大鼠和奶牛的精子顶体反应。然而，GABA浓度对精子功能的详细影响仍不清楚。本研究用免疫印迹法和免疫细胞化学法分别检测了小鼠附睾精子和精子顶体中GABA A型受体（GABAA）的存在。我们还研究了GABA对精子受精能力的影响。我们发现，GABA促进精子蛋白的酪氨酸磷酸化，这是精子获能的指标。GABA还促进顶体反应，这是由选择性GABAA受体拮抗剂抑制。然后，我们发现，顶体反应的有效GABA浓度对应于精子浓度，但我们没有检测到任何显着的影响GABA对精子活力使用计算机辅助精子分析系统。用免疫组织化学方法检测小鼠子宫和输卵管上皮中GABA的表达。此外，我们发现，谷氨酸脱羧酶（Gad），从L-谷氨酸产生GABA的mRNA水平，在输卵管比在子宫中更高，Gad mRNA水平在发情期比在间情期更高。这些结果表明，GABA浓度可以作为顶体反应和精子获能在雌性生殖道的调节剂。
In mammals, ejaculated sperm acquire their fertilizing ability during migration through the female reproductive tract, which secretes several factors that contribute to sperm capacitation. Gamma-aminobutyric acid (GABA) is a well-known neurotransmitter in the central nervous system, but additionally enhances the sperm acrosome reaction in the rat and cow. However, the detailed effects of GABA concentration on sperm function remain unclear. In this study, we detected the presence of the GABA type A receptor (GABA A) in mouse epididymal sperm by western blot analysis and in the sperm acrosome by immunocytochemistry. We also investigated the effects of GABA on sperm fertilizing ability. We found that GABA facilitated the tyrosine phosphorylation of sperm proteins, which is an index of sperm capacitation. GABA also promoted the acrosome reaction, which was suppressed by a selective GABA A receptor antagonist. We then found that the effective GABA concentration for the acrosome reaction corresponds to sperm concentration, but we did not detect any marked effect of GABA on sperm motility using a computer-assisted sperm analysis system. Using immunohistochemistry, we also detected GABA expression in the epithelia of the mouse uterus and oviduct. Furthermore, we found that the mRNA levels of glutamate decarboxylase (Gad), which generates GABA from L-glutamate, were higher in the oviduct than in the uterus, and that Gad mRNA levels were higher at estrus than at the diestrus stage. These results indicate that the GABA concentration can act as a modulator of the acrosome reaction and sperm capacitation in the female reproductive tract.