The Acrosome Reaction Induced by Dimethylsulfoxide in Sea Urchin Sperm |
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Authors: | KAORI MIKAMI-TAKEI AKIKO FUJIWARA IKUO YASUMASU |
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Institution: | Department of Biology, School of Education, Waseda University, 1-6-1, Nishiwaseda, Shinjuku-ku, Tokyo 160, Japan |
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Abstract: | The acrosome reaction in sea urchin sperm, as judged by disappearance of the acrosomal vesicles in Nomarski optics, was induced by dimethylsulfoxide (DMSO) at concentration above 0.1% in normal artificial sea water. The number of the acrosome-reacted spermatozoa increased in proportion to DMSO concentration. The DMSO-induced acrosome reaction, as well as the jelly water- or A23187-induced one, was inhibited by nifedipine and hardly occurred in Ca2+-free artificial sea water. However, the DMSO-induced acrosome reaction was found in a few number of spermatozoa in the presence of Ca2+at above 0.5 mM, though the jelly water- or A23187-induced acrosome reaction did not occur at external Ca2+levels lower than 1 mM. Dependency of the acrosome reaction by DMSO on external Ca2+is somewhat lower than that of the reaction by jelly water. In Ca2+-free artificial sea water, the acrosomal regions of DMSO-treated spermatozoa attached to their own tails. In some cases, spermatozoa thus treated with DMSO in Ca2+free artificial sea water caused formation of fertilization membrane in a few number of eggs kept in Ca2+-free artificial sea water. Even in the absence of extermal Ca2+, preliminary step of the acrosome reaction seems to be completed probably by DMSO-induced weak Ca2+-mobilization in spermatozoa. |
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