A fast transient hyperpolarization occurs during the sea urchin sperm acrosome reaction induced by egg jelly.
The egg jelly-induced sea urchin sperm depolarization, assayed with the membrane potential-sensitive dye diS-C3-(5), is preceded by a fast quenching, which was initially taken as an artifact. Here we show that part of this quenching results from a K+-dependent transient hyperpolarization (approximately 4 s). Seawater containing 25-35 mM KCl inhibits this hyperpolarization, the depolarization and the acrosome reaction induced by egg jelly, or by the acrosome reaction inducing factor purified therefrom. These results suggest that egg jelly induces a transient hyperpolarization mediated by an increase in K+ permeability, which may be involved in triggering the acrosome reaction.
D000177:Acrosome / Q000502:physiology*; D000818:Animals; D002463:Cell Membrane Permeability; D005260:Female; D008297:Male; D008564:Membrane Potentials / Q000187:drug effects; D010063:Ovum / Q000502:physiology*; D011188:Potassium / Q000378:metabolism; D011189:Potassium Chloride / Q000494:pharmacology; D011190:Potassium Cyanide / Q000494:pharmacology; D012617:Sea Urchins; D013050:Spectrometry, Fluorescence; D013094:Spermatozoa / Q000502:physiology*
D011189:Potassium Chloride; D011190:Potassium Cyanide; D011188:Potassium