A VOLATILE INHIBITOR IMMOBILIZES SEA-URCHIN SPERM IN SEMEN BY DEPRESSING THE INTRACELLULAR PH
A VOLATILE INHIBITOR IMMOBILIZES SEA-URCHIN SPERM IN SEMEN BY DEPRESSING THE INTRACELLULAR PH
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DOI：
10.1016/0012-1606(83)90378-0
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发表时间：
1983-01-01
影响因子：
2.7
通讯作者：
EPEL, D
中科院分区：
文献类型：
--
作者：
JOHNSON, CH;CLAPPER, DL;EPEL, D
海胆的精子在精液中通常是静止的，但可以通过增加精液上的气体流量来启动运动，例如，在一层薄薄的精液上吹氮气。这一结果表明精子的活力不受氧气的限制，并表明精液中含有一种挥发性的活力抑制物，这是导致精液中精子瘫痪的原因。这种抑制剂可能是二氧化碳，它可以可逆地固定精子。~(31)P-核磁共振pH测量表明，精液在海水中稀释后，精子胞内pH(Phi)增加0.36个pH单位。由于先前的研究表明，这种幅度的pH升高足以触发精子活力，挥发性抑制剂可能通过抑制phi来抑制精液中的精子活力。解释这些观察结果的一个简单假设是，挥发性运动抑制物是二氧化碳，它可以将phi酸化为一种可扩散的弱酸。在这方面，精子被稀释到海水中释放出酸；这种酸的释放与phi的增加和运动的启动有关。事实上，精子稀释后释放的酸中有近1/2是挥发性的，因此可能是由于二氧化碳排出。大多数酸不能归因于二氧化碳的释放，因为它不挥发。因此，当精子被稀释到海水中时，它们通过将二氧化碳和质子从细胞质释放到周围的海水中来提高其phi。
Sea urchin [Lytechinus pictus Strongylocentrotus purpuratus] spermatozoa are normally immotile in semen, but motility can be initiated by increasing gas flow over the semen, for example, by blowing N2 gas over a thin layer of semen. This result indicates that sperm motility is not O2 limited and suggests that seminal fluid contains a volatile inhibitor of motility which is responsible for the paralysis of sperm in semen. This inhibitor might be CO2, which reversibly immobilizes sperm. 31P-NMR measurements of pH show that the sperm intracellular pH (pHi) increases by 0.36 pH unit upon dilution of semen into seawater. Since previous studies have shown that this magnitude of pH increase is sufficient to trigger sperm motility, the volatile inhibitor may be inhibiting sperm motility in semen by depressing the pHi. A simple hypothesis that explains these observations is that the volatile motility inhibitor is CO2, which could acidify pHi as a diffusable weak acid. In this regard, sperm diluted into seawater release acid; this acid release is related to the pHi increase and motility initiation. In fact, nearly 1/2 of the acid released by sperm upon dilution is volatile and may therefore be due to CO2 efflux. Most of the acid, cannot be attributed to CO2 release because it is not volatile. Thus, when sperm are diluted into seawater, they raise their pHi by releasing CO2 and protons from the cytoplasm into the surrounding seawater.