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Does Phospholipase A 2 Participate in the Acrosome Reaction of Sea Urchin Sperm?: A Pharmacological Study
Author(s) -
Matsumura Kiyotaka,
Aketa Kenji
Publication year - 1991
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.1991.00365.x
Subject(s) - acrosome reaction , sea urchin , sperm , acrosome , ionomycin , activator (genetics) , phospholipase a , melittin , phospholipase a2 , chemistry , biology , intracellular , microbiology and biotechnology , biochemistry , enzyme , botany , membrane , receptor
We examined whether phospholipase A 2 (PLA 2 ) is involved in the initiation of the acrosome reaction of sperm of the sea urchin, Strongylocentrotus intermedius , using inhibitors and an activator of this enzyme. Quinacrine and p‐bromophenacyl bromide (PBPB) inhibited the egg jelly‐induced acrosome reaction at 100 μM, but not the ionomycin‐induced one. Depression of egg jelly‐induced increase of intracellular free Ca 2+ concentration ([Ca 2+ ] i ) by these reagents was expected and examined using fura 2. Quinacrine interfered with the flourescence of fura 2, but PBPB was found to depress at concentrations which could inhibit the acrosome reaction. Furthermore, melittin, which is known to stimulate PLA 2 , caused a [Ca 2+ ] i increase and a formation of acrosomal process‐like structure on sperm head. These results suggest that PLA 2 participates in the early step(s) of the acrosome reaction of sea urchin sperm.