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Calcium and Cyclic AMP Mediate Sperm Activation, but Ca 2+ Alone Contributes Sperm Chemotaxis in the Ascidian, Ciona savignyi
Author(s) -
Yoshida Manabu,
Inaba Kazuo,
Ishida Katsumi,
Morisawa Masaaki
Publication year - 1994
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.1994.00589.x
Subject(s) - sperm , chemotaxis , ciona , sea urchin , ciona intestinalis , sperm motility , strongylocentrotus purpuratus , biology , calcium , microbiology and biotechnology , chemistry , biochemistry , receptor , botany , organic chemistry , gene
Sperm‐activating and ‐attracting factor (SAAF) released from the ascidian, Ciona savignyi , was partially purified from egg seawater with ethanol extraction and separation with the two‐phase system of chloroform and water. SAAF did not activate sperm motility and cAMP synthesis in calcium‐free seawater (CaFSW), but activated the both in the presence of Ca 2+ . Sperm activation by SAAF in Ca 2+ ‐containing medium was inhibited by flunarizine, a T‐type Ca 2+ channel antagonist, but L‐type Ca 2+ channel specific antagonists had no effect. Theophylline, a phosphodiesterase inhibitor, induced the increase of cAMP level and sperm activation in CaFSW without SAAF. On the other hand, the theophylline‐activated sperm in CaFSW did not exhibit chemotaxis toward the tip of glass capillary containing SAAF, but upon the addition of Ca 2+ they were attracted toward SAAF in the same manner as chemotaxis in normal artificial seawater. These results suggest that sperm activation is induced by the increased cAMP level caused by Ca 2+ influx through T‐type Ca 2+ channel, and that Ca 2+ alone mediates the sperm chemotaxis in Ciona .