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 C /Ca 2C -exchanger (NCX) and the NaOn 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 K i (7.9!10 K9 and 9.8!10 K5 M), which is consistent with the presence of two isoforms of a subunit of the NKA in the sperm plasma membranes (a1 and a4), being a4 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 2C. We explain our results in terms of inhibition of the dynein-ATPase in the presence of higher cytosolic H C and Ca 2C, and therefore inhibition of sperm motility.

Semen characteristics in consecutive ejaculates with short abstinence in subfertile males

“…Therefore biochemical changes between first and consecutive ejaculates could help explain sperm motility changes. Similarly, biochemical changes such acidic pH and micromolar concentrations of Ca 2+ affect dynein-ATPase activities and therefore decrease sperm motility (Peralta-Arias et al, 2015) and this provides another possible explanation for observed differences between the two consecutive ejaculates.…”

Sperm Parameters before and after Swim-Up of a Second Ejaculate after a Short Period of Abstinence

“…Regarding the possible reasons for these improvements, the authors discussed also about the biochemical changes between the two consecutive ejaculates [9]. The decrease in Na + and Ca 2+ concentrations and the decrease in the cytoplasmic pH in spermatozoa from the caput to the cauda of the epididymis [29] could be involved in the increase in sperm motility in the second ejaculate.…”

Sodium-Hydrogen-Exchanger expression in human sperm and its relationship with semen parameters

“…Here, we found that the abnormal expression of sNHE is significantly associated with dysfunction of motility, indicating that this exchanger might be a target molecule of asthenozoospermia. In addition, Liu et al reported that immunization of female mice with the sNHE DNA vaccine showed decreased fecundity, since the antiserum and vaginal fluid in these immunized mice could induce sperm agglutination and decrease sperm motility; chemical inhibitor of NHE, amiloride, also showed the potential of impeding sperm motility, suggesting that these inhibitors of sNHE applied as contraceptive needed to be further investigated [34,35].…”