Alavi Sayyed Mohammad Hadi, Cosson Jacky
Department of Fisheries and Environmental Sciences, Faculty of Natural Resources, University of Tehran, P.O. Box: 31585-4314, Karaj, Iran.
Cell Biol Int. 2006 Jan;30(1):1-14. doi: 10.1016/j.cellbi.2005.06.004. Epub 2005 Nov 8.
The spermatozoa of most fish species are immotile in the testis and seminal plasma. Therefore, motility is induced after the spermatozoa are released into the aqueous environment during natural reproduction or into the diluent during artificial reproduction. There are clear relationships between seminal plasma composition and osmolality and the duration of fish sperm motility. Various parameters such as ion concentrations (K+, Na+, and Ca2+), osmotic pressure, pH, temperature and dilution rate affect motility. In the present paper, we review the roles of these ions on sperm motility in Salmonidae, Cyprinidae, Acipenseridae and marine fishes, and their relationship with seminal plasma composition. Results in the literature show that: 1. K+ is a key ion controlling sperm motility in Salmonidae and Acipenseridae in combination with osmotic pressure; this control is more simple in other fish species: sperm motility is prevented when the osmotic pressure is high (Cyprinidae) or low (marine fishes) compared to that of the seminal fluid. 2. Cations (mostly divalent, such as Ca2+) are antagonistic with the inhibitory effect of K+ on sperm motility. 3. In many species, Ca2+ influx and K+ or Na+ efflux through specific ionic channels change the membrane potential and eventually lead to an increase in cAMP concentration in the cell, which constitutes the initiation signal for sperm motility in Salmonidae. 4. Media that are hyper- and hypo-osmotic relative to seminal fluid trigger sperm motility in marine and freshwater fishes, respectively. 5. The motility of fish spermatozoa is controlled through their sensitivity to osmolality and ion concentrations. This phenomenon is related to ionic channel activities in the membrane and governs the motility mechanisms of axonemes.
大多数鱼类的精子在睾丸和精浆中是不活动的。因此，在自然繁殖过程中精子释放到水环境中或人工繁殖过程中释放到稀释液中后，精子的活动能力才会被诱导出来。精浆成分、渗透压与鱼类精子活动持续时间之间存在明确的关系。离子浓度（K⁺、Na⁺和Ca²⁺）、渗透压、pH值、温度和稀释率等各种参数都会影响精子的活动能力。在本文中，我们综述了这些离子在鲑科、鲤科、鲟科鱼类和海水鱼类精子活动中的作用，以及它们与精浆成分的关系。文献结果表明：1. 在鲑科和鲟科鱼类中，K⁺是与渗透压共同控制精子活动的关键离子；在其他鱼类中，这种控制更为简单：与精液相比，当渗透压高（鲤科）或低（海水鱼类）时，精子活动能力受到抑制。2. 阳离子（主要是二价阳离子，如Ca²⁺）与K⁺对精子活动的抑制作用相互拮抗。3. 在许多物种中，Ca²⁺通过特定离子通道内流以及K⁺或Na⁺外流会改变膜电位，最终导致细胞内cAMP浓度升高，这构成了鲑科鱼类精子活动的起始信号。4. 相对于精液，高渗和低渗介质分别触发海水鱼和淡水鱼的精子活动。5. 鱼类精子的活动能力通过它们对渗透压和离子浓度的敏感性来控制。这种现象与膜中的离子通道活性有关，并支配着轴丝的活动机制。
