title: Fowl (Gallus domesticus) sperm motility depends upon mitochondrial calcium cycling driven by extracellular sodium.
abstract: A relationship between extracellular Ca(+2), fowl sperm phospholipase A2 activity, long-chain acylcarnitine content, and motility was demonstrated in previous work. Sperm motility appeared to depend upon Na+-dependent Ca(+2) cycling when sperm were incubated at body temperature without glucose. In the present work, motility decreased as a function of time when sperm were incubated in 2 mM Ca(+2) prepared with either buffered isotonic sucrose or LiCl. However, this effect was less pronounced in the case of LiCl. The sparing effect of Li+ was attributed to the mitochondrial Na+/Ca(+2) exchanger. Motile concentration decreased exponentially in response to micromolar concentrations of CGP 37157, a specific inhibitor of the mitochondrial Na+/Ca(+2) exchanger. KB-R7943 mesylate, an inhibitor of the reverse mode of the Na+/Ca(+2) exchanger, prevented re-initiation of motility when exogenous Ca(+2) was added to sperm rendered immotile by incubation with 1,2-bis-(o-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid, a high-affinity Ca(+2) chelator. The presence of voltage-gated Ca(+2) channels was confirmed by the effect of nifedipine on motile concentration. Neither motile concentration nor straight line velocity was affected by either ouabain or orthovanadate, which inhibit Na+-K+ ATPase and Ca(+2)-ATPase, respectively. In summary, we infer that 1) fowl sperm motility is dependent upon extracellular Ca(+2) cycling through mitochondria; 2) such cycling is dependent upon extracellular Na+; and 3) fowl sperm conserve ATP by moving neither Na+ nor Ca(+2) by active transport. Understanding the relationship between mitochondrial Ca(+2) cycling and ATP production may be applicable to long-term semen storage.
authors.affiliation: Department of Animal Sciences, Oregon State University, Corvallis, Oregon 97331, USA. David.Froman@oregonstate.edu
authors.forename: D P
authors.initials: DP
authors.lastname: Froman
authors.forename: A J
authors.initials: AJ
authors.lastname: Feltmann
mesh_terms: D000818:Animals; D002118:Calcium / Q000378:metabolism*; D020013:Calcium Signaling; D000252:Calcium-Transporting ATPases / Q000037:antagonists & inhibitors / Q000378:metabolism; D002478:Cells, Cultured; D002645:Chickens / Q000502:physiology*; D002998:Clonazepam / Q000031:analogs & derivatives* / Q000494:pharmacology; D004533:Egtazic Acid / Q000031:analogs & derivatives* / Q000494:pharmacology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005109:Extracellular Matrix / Q000187:drug effects / Q000378:metabolism*; D018021:Lithium Chloride / Q000494:pharmacology; D008297:Male; D008928:Mitochondria / Q000187:drug effects / Q000378:metabolism*; D010042:Ouabain / Q000494:pharmacology; D012964:Sodium / Q000378:metabolism*; D019831:Sodium-Calcium Exchanger / Q000037:antagonists & inhibitors / Q000378:metabolism; D013081:Sperm Motility / Q000187:drug effects / Q000502:physiology*; D013841:Thiazepines / Q000494:pharmacology; D013890:Thiourea / Q000031:analogs & derivatives* / Q000494:pharmacology
chemical_list: C101670:2-(2-(4-(4-nitrobenzyloxy)phenyl)ethyl)isothiourea methanesulfonate; D004791:Enzyme Inhibitors; D019831:Sodium-Calcium Exchanger; D013841:Thiazepines; D004533:Egtazic Acid; D010042:Ouabain; D002998:Clonazepam; C079032:CGP 37157; D012964:Sodium; D000252:Calcium-Transporting ATPases; D018021:Lithium Chloride; D013890:Thiourea; C025603:1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid; D002118:Calcium