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The Role of External Potassium Ion in Activation of Sea Urchin Spermatozoa
Author(s) -
MITA MASATOSHI,
YASUMASU IKUO
Publication year - 1984
Publication title -
development, growth and differentiation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.864
H-Index - 66
eISSN - 1440-169X
pISSN - 0012-1592
DOI - 10.1111/j.1440-169x.1984.00489.x
Subject(s) - hemicentrotus , sea urchin , seawater , sperm , respiration , dilution , sperm motility , chemistry , potassium , artificial seawater , biology , biophysics , botany , ecology , physics , thermodynamics , organic chemistry
When sperm of the sea urchin, Hemicentrotus pulcherrimus, are diluted into K + ‐free seawater, the pH of the suspension gradually decreases, whereas a rapid decline in pH is observed following dilution into regular seawater. Sperm motility and respiration are also activated after dilution into K + ‐free seawater, but levels of activity are less than those observed following dilution into regular seawater. Upon addition of 10 mM K + to K + ‐free seawater, rapid acid release occurs and motility and respiratory rate in sperm are reactivated. The effect of K + on respiration was competitive with respect to the external Na + concentrations. Harmaline, a potent inhibitor of Na + /K + ‐ATPase, causes a decrease in movement and respiration of the sperm. Harmaline does not inhibit the rapid decline in pH, although it depresses the release of acid from mitochondria. These results suggest that external K + plays an important role in intracellular alkalinization of sea urchin sperm.