Role of ions and ion channels in the regulation of Atlantic croaker sperm motility.
The effects of the osmolarity and ionic composition of the external media and ion-channel blockers on the induction of sperm motility in the marine teleost, Atlantic croaker (Micropogonias undulatus) were investigated. An in vitro sperm motility assay was developed to determine treatment effects on the percentage of motile sperm, sperm speed, and turning rate, using a computer-aided motion-analysis system. Maximum activation of sperm motility occurred in saline with an osmolarity of 680 mOs/kg. Potassium caused a decrease in the percentage of motile sperm, but only at high nonphysiological concentrations in the presence of high amounts of calcium. Calcium caused an increase in sperm velocity and turning rate. Percent motility was inhibited by the potassium-channel blockers, 4-aminopyridine and veratrine, the calcium-channel blockers, verapamil, diltiazem, and nifedipine; the sodium-channel blocker, amiloride, and the chloride-channel blocker, ethacrynic acid. In addition, the calcium-channel blockers caused a decrease in sperm velocity and turning rate. These results provide evidence for the role of potassium, calcium, and possibly sodium, and chloride ions in Atlantic croaker sperm motility. In addition, this study demonstrates that membrane-bound ion channels are involved in the motility of sperm from a marine teleost.
Detweiler
C
C
University of Texas Marine Science Institute, Port Aransas 78373, USA.
Thomas
P
P
D000818:Animals; D002121:Calcium Channel Blockers / Q000494:pharmacology; D018118:Chloride Channels / Q000037:antagonists & inhibitors; D007473:Ion Channels / Q000378:metabolism*; D008297:Male; D009997:Osmotic Pressure; D010473:Perciformes / Q000502:physiology*; D026902:Potassium Channel Blockers; D012623:Seawater; D012661:Semen / Q000737:chemistry; D026941:Sodium Channel Blockers; D013081:Sperm Motility / Q000187:drug effects / Q000502:physiology*; D013997:Time Factors
D002121:Calcium Channel Blockers; D018118:Chloride Channels; D007473:Ion Channels; D026902:Potassium Channel Blockers; D026941:Sodium Channel Blockers