Potassium ion influx and Na+,K+-ATPase activity are required for the hamster sperm acrosome reaction - PubMed (original) (raw)

Potassium ion influx and Na+,K+-ATPase activity are required for the hamster sperm acrosome reaction

R J Mrsny et al. J Cell Biol. 1981 Oct.

Abstract

The role of a K+ ion influx and Na+,K+-ATPase activity in the hamster sperm acrosome reaction (AR) was examined, using a range of concentrations of K+,K+ ionophores and a Na+,K+-ATPase inhibitor. Washed epididymal hamster sperm, capacitated in vitro in an artificial medium containing 2 mM Ca2+, 147 mM Na+, and 3, 6, 12, 18, or 24 mM K+, began undergoing the AR after 3 h of incubation. Sperm incubated in low K+ (0.9 mM) failed to undergo the AR even after 5 h of incubation. Sperm in 0.9 mM K+ could be induced to undergo the AR when either K+ (12 mM) alone or K+ (12 mM) with 0.1 microM nigericin was added after 3.5 h of incubation. The addition of K+ alone stimulated the AR in 30 min, whereas nigericin plus K+ stimulated the AR 15 min after addition. Neither nigericin added alone (0.9 mM K+) nor nigericin plus 12 mM K+ added to a low Ca2+ (0.35 mM) system resulted in acrosome reactions. Valinomycin (1 nM) did not stimulate the AR when added together with K+ (3-24 mM) to sperm incubated in 0.9 mM K+ for 3.5 h but markedly decreased sperm motility. Micromolar levels of ouabain blocked the AR when added between t = 0--3 h to sperm incubated with 3-24 mM K+. Inhibition of AR by the addition of 1 microM ouabain to sperm incubated with 3 mM K+ was completely reversed by the addition of 0.1 microM nigericin at t = 3.5 h. These results suggest that Na+,K+-ATPase activity and the resulting K+ influx are important for the mammalian sperm AR. Some similarities between requirements for the hamster sperm AR and secretory granule exocytosis are discussed.

PubMed Disclaimer

Similar articles

Cited by

References

    1. Nature. 1966 Jan 22;209(5021):403 - PubMed
    1. J Pharmacol Exp Ther. 1964 Apr;144:110-5 - PubMed
    1. J Gen Physiol. 1967 Dec;50(11):2527-45 - PubMed
    1. J Ultrastruct Res. 1969 Jan;26(1):31-43 - PubMed
    1. Experientia. 1970 Jan 15;26(1):20-1 - PubMed

Publication types

MeSH terms

Substances

LinkOut - more resources