title: ATPases, ion exchangers and human sperm motility.
abstract: Human sperm has several mechanisms to control its ionic milieu, such as the Na,K-ATPase (NKA), the Ca-ATPase of the plasma membrane (PMCA), the Na(+)/Ca(2) (+)-exchanger (NCX) and the Na(+)/H(+)-exchanger (NHE). On the other hand, the dynein-ATPase is the intracellular motor for sperm motility. In this work, we evaluated NKA, PMCA, NHE, NCX and dynein-ATPase activities in human sperm and investigated their correlation with sperm motility. Sperm motility was measured by Computer Assisted Semen Analysis. It was found that the NKA activity is inhibited by ouabain with two Ki (7.9 × 10(-9) and 9.8 × 10(-5) M), which is consistent with the presence of two isoforms of α subunit of the NKA in the sperm plasma membranes (α1 and α4), being α4 more sensitive to ouabain. The decrease in NKA activity is associated with a reduction in sperm motility. In addition, sperm motility was evaluated in the presence of known inhibitors of NHE, PMCA and NCX, such as amiloride, eosin, and KB-R7943, respectively, as well as in the presence of nigericin after incubation with ouabain. Amiloride, eosin and KB-R7943 significantly reduced sperm motility. Nigericin reversed the effect of ouabain and amiloride on sperm motility. Dynein-ATPase activity was inhibited by acidic pH and micromolar concentrations of Ca(2) (+). We explain our results in terms of inhibition of the dynein-ATPase in the presence of higher cytosolic H(+) and Ca(2) (+), and therefore inhibition of sperm motility.
authors.affiliation: Laboratorio de Bioenergética CelularInstituto Venezolano de Investigaciones Científicas (IVIC-CBB), AP 21827, Caracas 1020A, VenezuelaDepartamento de Biología de OrganismosUniversidad Simón Bolívar, Caracas, VenezuelaLaboferclaMaternidad Leopoldo Aguerrevere, Caracas, Venezuela.
authors.forename: Rubén D
authors.initials: RD
authors.lastname: Peralta-Arias
authors.affiliation: Laboratorio de Bioenergética CelularInstituto Venezolano de Investigaciones Científicas (IVIC-CBB), AP 21827, Caracas 1020A, VenezuelaDepartamento de Biología de OrganismosUniversidad Simón Bolívar, Caracas, VenezuelaLaboferclaMaternidad Leopoldo Aguerrevere, Caracas, Venezuela.
authors.forename: Carmen Y
authors.initials: CY
authors.lastname: Vívenes
authors.affiliation: Laboratorio de Bioenergética CelularInstituto Venezolano de Investigaciones Científicas (IVIC-CBB), AP 21827, Caracas 1020A, VenezuelaDepartamento de Biología de OrganismosUniversidad Simón Bolívar, Caracas, VenezuelaLaboferclaMaternidad Leopoldo Aguerrevere, Caracas, Venezuela.
authors.forename: María I
authors.initials: MI
authors.lastname: Camejo
authors.affiliation: Laboratorio de Bioenergética CelularInstituto Venezolano de Investigaciones Científicas (IVIC-CBB), AP 21827, Caracas 1020A, VenezuelaDepartamento de Biología de OrganismosUniversidad Simón Bolívar, Caracas, VenezuelaLaboferclaMaternidad Leopoldo Aguerrevere, Caracas, Venezuela.
authors.forename: Sandy
authors.initials: S
authors.lastname: Piñero
authors.affiliation: Laboratorio de Bioenergética CelularInstituto Venezolano de Investigaciones Científicas (IVIC-CBB), AP 21827, Caracas 1020A, VenezuelaDepartamento de Biología de OrganismosUniversidad Simón Bolívar, Caracas, VenezuelaLaboferclaMaternidad Leopoldo Aguerrevere, Caracas, Venezuela.
authors.forename: Teresa
authors.initials: T
authors.lastname: Proverbio
authors.affiliation: Laboratorio de Bioenergética CelularInstituto Venezolano de Investigaciones Científicas (IVIC-CBB), AP 21827, Caracas 1020A, VenezuelaDepartamento de Biología de OrganismosUniversidad Simón Bolívar, Caracas, VenezuelaLaboferclaMaternidad Leopoldo Aguerrevere, Caracas, Venezuela.
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Martínez
authors.affiliation: Laboratorio de Bioenergética CelularInstituto Venezolano de Investigaciones Científicas (IVIC-CBB), AP 21827, Caracas 1020A, VenezuelaDepartamento de Biología de OrganismosUniversidad Simón Bolívar, Caracas, VenezuelaLaboferclaMaternidad Leopoldo Aguerrevere, Caracas, Venezuela.
authors.forename: Reinaldo
authors.initials: R
authors.lastname: Marín
authors.affiliation: Laboratorio de Bioenergética CelularInstituto Venezolano de Investigaciones Científicas (IVIC-CBB), AP 21827, Caracas 1020A, VenezuelaDepartamento de Biología de OrganismosUniversidad Simón Bolívar, Caracas, VenezuelaLaboferclaMaternidad Leopoldo Aguerrevere, Caracas, Venezuela fproverb@yahoo.com fproverb@ivic.gob.ve.
authors.forename: Fulgencio
authors.initials: F
authors.lastname: Proverbio
mesh_terms: D002118:Calcium / Q000494:pharmacology*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006801:Humans; D007474:Ion Exchange; D008297:Male; D017923:Sodium-Hydrogen Exchangers / Q000378:metabolism*; D000254:Sodium-Potassium-Exchanging ATPase / Q000037:antagonists & inhibitors / Q000378:metabolism*; D013081:Sperm Motility / Q000187:drug effects / Q000502:physiology*; D013094:Spermatozoa / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*
chemical_list: D004791:Enzyme Inhibitors; D017923:Sodium-Hydrogen Exchangers; D000254:Sodium-Potassium-Exchanging ATPase; D002118:Calcium