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Regulation of flagellar bending by cAMP and Ca 2+ in hamster sperm
Author(s) -
Aoki Fugaku,
Sakai Senkiti,
Kohmoto Kaoru
Publication year - 1999
Publication title -
molecular reproduction and development
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.745
H-Index - 105
eISSN - 1098-2795
pISSN - 1040-452X
DOI - 10.1002/(sici)1098-2795(199905)53:1<77::aid-mrd9>3.0.co;2-c
Subject(s) - sperm , flagellum , biology , hamster , extracellular , calmodulin , intracellular , microbiology and biotechnology , mesocricetus , biophysics , biochemistry , endocrinology , genetics , gene , enzyme
Hamster sperm were immotile in the medium at free Ca 2+ concentrations ([Ca 2+ ]) below 1 × 10 –4 M. The flagellum was acutely bent in the opposite direction to the curve of the hook‐shaped heads. This phenomenon seemed to be caused by the decrease in the intracellular cAMP concentration, since the cAMP concentration was low at [Ca 2+ ] below 1 × 10 –4 M and increased abruptly at 1 × 10 –3 M, at which sperm were swimming actively. In addition, sperm became motile due to treatment with 8‐bromo‐cAMP, a membrane permeable analogue of cAMP, in a medium without Ca 2+ . These results suggested that extracellular Ca 2+ is involved in the regulation of flagellar movement via increasing intracellular cAMP concentration. By the treatment with W‐13, a calmodulin inhibitor, sperm also became motile, although cAMP concentration remained at a low level. These results suggested that cAMP is not always required for the flagellar movement when the function of calmodulin is depressed. Mol. Reprod. Dev. 53:77–83, 1999. © 1999 Wiley‐Liss, Inc.