Evidence in support of a role for Ca(2+)-activated K+ channels in the hamster sperm acrosome reaction.
The sperm acrosome reaction (AR) is a crucial step for mammalian fertilization. This work describes experiments to test the effect of the cesium ion (Cs+) and charybdotoxin (ChTX) on the Ca2+ or Na+/K+ ionophores stimulated hamster sperm AR in vitro. Cs+ and ChTX, a polypeptide toxin from the venom of the scorpion Leirus quinquestriatus, are considered blockers of Ca(2+)-activated K+ channels in several somatic cells. Both agents inhibited the AR by 55-66%. The inhibition was completely reversed by the Na+/K+ ionophore nigericin, but not by the Ca2+ ionophore A-23187. Results give evidence in support of a role for Ca(2+)-activated K+ channels in K+ influx required for the occurrence of the hamster sperm acrosome reaction.
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Unit of Reproductive Biology, INTA, University of Chile, Santiago.
D000177:Acrosome / Q000187:drug effects / Q000502:physiology*; D000818:Animals; D000001:Calcimycin / Q000494:pharmacology; D018999:Charybdotoxin; D006224:Cricetinae; D005260:Female; D008297:Male; D009550:Nigericin / Q000494:pharmacology; D011188:Potassium / Q000494:pharmacology*; D015221:Potassium Channels / Q000187:drug effects / Q000502:physiology*; D012604:Scorpion Venoms / Q000494:pharmacology; D013081:Sperm Motility; D013084:Sperm-Ovum Interactions / Q000502:physiology*; D013094:Spermatozoa / Q000187:drug effects / Q000502:physiology*
D015221:Potassium Channels; D012604:Scorpion Venoms; D018999:Charybdotoxin; D000001:Calcimycin; D009550:Nigericin; D011188:Potassium