Turner K O, Meizel S
Department of Cell Biology and Human Anatomy, School of Medicine, University of California, Davis 95616-8643, USA.
Biochem Biophys Res Commun. 1995 Aug 24;213(3):774-80. doi: 10.1006/bbrc.1995.2197.
Progesterone is capable of initiating the mammalian sperm acrosome reaction in vitro and is a putative initiator of this essential fertilization event in vivo. Our previous work has suggested that progesterone initiates the human sperm acrosome reaction, at least in part, by activating a unique steroid receptor/Cl- channel resembling a gamma-aminobutyric acidA receptor/Cl- channel (gamma-aminobutyric acidA-like receptor/Cl- channel). Here, the fluorescent intracellular Cl- probe, 6-methoxy-N-ethylquinolinium, was used to detect qualitative changes in sperm cytosolic Cl-. We demonstrate that progesterone can mediate a rapid transient decrease of human sperm cytosolic Cl- inhibitable by the gamma-aminobutyric acidA receptor/Cl- channel antagonists picrotoxin and (+)-bicuculline (which also inhibit the acrosome reaction). These results support the involvement of a gamma-aminobutyric acidA-like receptor/Cl- channel in the P-mediated human acrosome reaction and are the first to demonstrate that a rapid Cl- efflux plays a role in that event.
孕酮能够在体外引发哺乳动物精子顶体反应，并且在体内是这一关键受精事件的假定启动因子。我们之前的研究表明，孕酮至少部分地通过激活一种独特的类固醇受体/氯离子通道来引发人类精子顶体反应，该通道类似于γ-氨基丁酸A受体/氯离子通道（γ-氨基丁酸A样受体/氯离子通道）。在此，使用荧光细胞内氯离子探针6-甲氧基-N-乙基喹啉鎓来检测精子胞质氯离子的定性变化。我们证明，孕酮可介导人类精子胞质氯离子的快速短暂减少，这种减少可被γ-氨基丁酸A受体/氯离子通道拮抗剂印防己毒素和（+）-荷包牡丹碱抑制（它们也抑制顶体反应）。这些结果支持γ-氨基丁酸A样受体/氯离子通道参与孕酮介导的人类顶体反应，并且首次证明快速氯离子外流在该事件中起作用。
