Verapamil, a Ca2+ channel antagonist, accelerates the in vitro penetration of zona-free hamster eggs by human spermatozoa.
Human spermatozoa were preincubated for 3.5 h with various concentrations (0-100 mumol/l) of verapamil, a Ca2+ channel antagonist, before they were mixed with zona-free hamster eggs. Control spermatozoa penetrated only 3% of the eggs, whereas the highest penetration (40.3%) was reached after preincubation with 100 mumol/l verapamil. Thus, verapamil increases the ability of human spermatozoa to penetrate zona-free hamster eggs, possibly by an acceleration of the acrosome reaction. Although it has been established that the acrosome reaction requires the entry of extracellular Ca2+ into the spermatozoa, the Ca2+ ions do not seem to enter by means of Ca2+ channels.
Department of Anatomy and Reproductive Biology, University of Hawaii School of Medicine, Honolulu 96822.
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Roldan
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Wramsby
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Yanagimachi
D000177:Acrosome / Q000378:metabolism; D000818:Animals; D002118:Calcium / Q000378:metabolism; D006224:Cricetinae; D005260:Female; D005307:Fertilization in Vitro / Q000187:drug effects; D006801:Humans; D008297:Male; D013084:Sperm-Ovum Interactions / Q000187:drug effects*; D013094:Spermatozoa / Q000187:drug effects* / Q000378:metabolism; D014700:Verapamil / Q000494:pharmacology*; D015044:Zona Pellucida
D014700:Verapamil; D002118:Calcium