title: Effects of ions on the motility of fresh and demembranated paddlefish (Polyodon spathula) spermatozoa.
abstract: This study investigated the effects of different environmental conditions on the motility parameters of paddlefish (Polyodon spathula) spermatozoa. Paddlefish spermatozoa demonstrated the following characteristics: (i) all spermatozoa were motile 10 s after activation with a velocity of 130-160 microm s(-1); (ii) after 2 min, velocity decreased to 80-130 microm s(-1); and (iii) motility was maintained for up to 9 min. Concentrations of 0.5-5.0 mmol KCl l(-1) prevented activation of spermatozoa. After transfer into a swimming medium (20 mmol Tris l(-1), pH 8.2 and 1 mg BSA ml(-1)) containing 0.5 mmol KCl l(-1) (combined with 5 mmol NaCl or MgCl(2) l(-1)), 80-100% of cells were motile with a velocity of about 120-150 microm s(-1). MgCl(2) significantly improved the velocity of spermatozoa at 10, 40, 50 and 60 s after activation and the stable velocity of spermatozoa was about 140 microm s(-1). Very low concentrations of CaCl(2) (0.125 mmol l(-1)) combined with 0.5 mmol KCl l(-1) initiated motility in 20% of spermatozoa, whereas all spermatozoa were activated after 2 min with 0.25 mmol CaCl(2) l(-1) in similar medium for the full period of swimming with velocity of about 120 microm s(-1). This study demonstrated that potassium (5-15 mmol l(-1)) inhibits demembranated spermatozoa. Thus, initiation of movement in paddlefish spermatozoa is under the reciprocal control of potassium and calcium ion concentrations.
authors.affiliation: Joint Laboratory of Genetics, Physiology and Reproduction of Fish, Institute of Animal Physiology and Genetics, 38925 Vodnany, Czech Republic. linhart@vurh.jcu.cz
authors.forename: O
authors.initials: O
authors.lastname: Linhart
authors.forename: J
authors.initials: J
authors.lastname: Cosson
authors.forename: S D
authors.initials: SD
authors.lastname: Mims
authors.forename: W L
authors.initials: WL
authors.lastname: Shelton
authors.forename: M
authors.initials: M
authors.lastname: Rodina
mesh_terms: D000818:Animals; D002118:Calcium / Q000502:physiology*; D002462:Cell Membrane / Q000502:physiology; D002478:Cells, Cultured; D005399:Fishes / Q000502:physiology*; D007477:Ions; D008297:Male; D018715:Microscopy, Video; D009994:Osmolar Concentration; D011188:Potassium / Q000502:physiology*; D013081:Sperm Motility / Q000502:physiology*
chemical_list: D007477:Ions; D011188:Potassium; D002118:Calcium