Calcium-induced quiescence of sperm motility in the bluegill (Lepomis macrochirus).
Before dilution in hypoosmotic media sperm of freshwater fish are maintained quiescent by a range of factors including osmolality, K+ and pH, and the onset of motility is generally associated with an increase in cytoplasmic Ca2+. In contrast, Ca2+ in conjunction with osmolality was found to inhibit motility of intact bluegill sperm. Consistent with seminal plasma composition, 0.16 mmol/L Ca2+ and greater, in conjunction with an osmotic concentration of 290 mOsm/kg, inhibited the onset of bluegill sperm motility; sperm diluted in saline at 290 mOsm/kg without Ca2+ became motile. Cations Mn2+ and Sr2+, in conjunction with osmolality, had an inhibitory effect on initiation of sperm motility similar to that of Ca2+. Sperm motility was inhibited by Ca2+ channel blockers nimodipine and nifedipine, the mitochondrial Ca2+ uniporter inhibitor ruthenium red and the calmodulin inhibitors W-7 and trifluoperazine dihydrochloride. These results provide evidence that elevated cytoplasmic Ca2+ inhibits sperm motility and yet low levels permit or promote motility. This study demonstrates a unique inhibitory action of Ca2+ on the motility of intact fish sperm at physiologically relevant levels.
Zuccarelli
Micah D
MD
Department of Biological Sciences, Center for Reproductive Biology, University of Idaho, Moscow, Idaho, USA.
Ingermann
Rolf L
RL
D000818:Animals; D002121:Calcium Channel Blockers / Q000494:pharmacology; D002122:Calcium Chloride / Q000494:pharmacology*; D002712:Chlorides / Q000494:pharmacology; D003593:Cytoplasm / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004347:Drug Interactions; D008297:Male; D017895:Manganese Compounds / Q000494:pharmacology; D009543:Nifedipine / Q000494:pharmacology; D009553:Nimodipine / Q000494:pharmacology; D009995:Osmosis; D009997:Osmotic Pressure; D010473:Perciformes / Q000502:physiology*; D012430:Ruthenium Red / Q000494:pharmacology; D012661:Semen / Q000737:chemistry; D013081:Sperm Motility / Q000187:drug effects* / Q000502:physiology; D013094:Spermatozoa / Q000187:drug effects* / Q000502:physiology; D013324:Strontium / Q000494:pharmacology; D013449:Sulfonamides / Q000494:pharmacology; D014268:Trifluoperazine / Q000494:pharmacology
D002121:Calcium Channel Blockers; D002712:Chlorides; D017895:Manganese Compounds; D013449:Sulfonamides; D012430:Ruthenium Red; D014268:Trifluoperazine; D009553:Nimodipine; C017967:W 7; C025700:strontium chloride; D009543:Nifedipine; D002122:Calcium Chloride; C025340:manganese chloride; D013324:Strontium