Perchec Poupard G, Gatti J L, Cosson J, Jeulin C, Fierville F, Billard R
Laboratoire d'Ichtyologie Générale et Appliquée, URM n.3, Muséum National d'Histoire Naturelle, Paris, France.
J Reprod Fertil. 1997 Jul;110(2):315-27. doi: 10.1530/jrf.0.1100315.
The mechanism by which a hypo-osmotic shock activates motility of carp spermatozoa was studied. The direct role of osmolality at the axoneme was investigated after demembranation of spermatozoa with Triton X-100 and reactivation in various ionic or anionic solutions containing Mg-ATP: demembranated spermatozoa remain motile in solutions of osmolality up to 550 mOsm kg-1 while non-demembranated spermatozoa are immotile when osmolality rises above 250 mOsm kg-1 with the same salt solutions as well as in non-ionic solutions. Suspension in hypo-osmotic saline solutions triggered the swelling of native carp spermatozoa. No motility or swelling occurred above 200-300 mOsm kg-1 and this osmolality is probably that of the cytosol. The swelling of carp spermatozoa is the result of an entrance of water but this was not affected by pCMBS, an inhibitor of the aquaporin CHIP28, or by various inhibitors of the co-transport of water with ions. Various pharmacological agents that affect the motility of different sperm species had no effect on carp sperm motility when used under similar conditions. However, prolonged exposure to a solution devoid of K+ or Cl- affects the activation of motility in a reversible manner, suggesting that these ions have a role in the perception or transduction of the osmotic signal. Altering the concentration of intracellular second messengers such as Ca2+ and cAMP, and the pH did not affect the motility of carp spermatozoa. However, DMSO at 1-20% (400-3200 mOsm kg-1) affects the motility of carp spermatozoa 3-4 min after mixing. These results show that the activation signal of carp sperm motility differs from that known for spermatozoa of other species of fish such as trout. Our results indicate that the activation mechanism may involve a co-transport of ions or specific 'stretch-activated channels' that are sensitive to osmotic pressure.
研究了低渗休克激活鲤鱼精子运动的机制。在用Triton X-100使精子去膜并在含有Mg-ATP的各种离子或阴离子溶液中重新激活后，研究了轴丝处渗透压的直接作用：去膜精子在渗透压高达550 mOsm kg-1的溶液中仍能运动，而未去膜精子在渗透压高于250 mOsm kg-1时则不能运动，所用盐溶液相同，在非离子溶液中也是如此。悬浮于低渗盐溶液中会引发天然鲤鱼精子的肿胀。在200 - 300 mOsm kg-1以上不会发生运动或肿胀，这个渗透压可能就是细胞质溶胶的渗透压。鲤鱼精子的肿胀是水进入的结果，但这不受水通道蛋白CHIP28的抑制剂pCMBS或水与离子协同转运的各种抑制剂的影响。在类似条件下使用时，各种影响不同物种精子运动的药物对鲤鱼精子运动没有影响。然而，长时间暴露于不含K+或Cl-的溶液中会以可逆方式影响运动的激活，表明这些离子在渗透信号的感知或转导中起作用。改变细胞内第二信使如Ca2+和cAMP的浓度以及pH值不会影响鲤鱼精子的运动。然而，1 - 20%（400 - 3200 mOsm kg-1）的二甲基亚砜在混合后3 - 4分钟会影响鲤鱼精子的运动。这些结果表明，鲤鱼精子运动的激活信号与其他鱼类如鳟鱼精子的已知信号不同。我们的结果表明，激活机制可能涉及离子的协同转运或对渗透压敏感的特定“牵张激活通道”。
