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Cell Biology International (2006) 30, 1–14 (Printed in Great Britain)
Sperm motility in fishes. (II) Effects of ions and osmolality: A review
Sayyed Mohammad Hadi Alavia and Jacky Cossonb*
aDepartment of Fisheries and Environmental Sciences, Faculty of Natural Resources, University of Tehran, P.O. Box: 31585-4314, Karaj, Iran
bLaboratory of Developmental Biology, UMR 7009 CNRS, University Pierre et Marie Curie, F-06230 Villefranche-sur-Mer, France


Abstract

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.


Key words: Calcium (Ca2+), Cyprinids, Motility initiation, Osmotic pressure, Potassium (K+), Salmonids, Sodium (Na+), Sperm motility, Spermatozoa, Sturgeon.

*Corresponding author.


Received 24 November 2004/27 May 2005; accepted 8 June 2005

doi:10.1016/j.cellbi.2005.06.004


ISSN Print: 1065-6995
ISSN Electronic: 1095-8355
Published by Portland Press Limited on behalf of the International Federation for Cell Biology (IFCB)