Single-channel activity of bilayers derived from sea urchin sperm plasma membranes at the tip of a patch-clamp electrode.
Changes in the plasma membrane permeability of echinoderm sperm play a fundamental role in the acrosome reaction. During the reaction there is an increase in intracellular Ca2+ and Na+ and an efflux of H+ and K+. We have formed bilayers at the tip of patch pipets from a mixture of lipid vesicles and sea urchin sperm plasma membranes (12-50 microgram protein/ml). We observed three types of K+ channels (conductances: 22, 46, and 82 pS), two of which are partially blocked by TEA, and one Cl- channel (148 pS). The presence of K+ channels in sperm plasma membranes is consistent with the inhibition by TEA of the acrosome reaction in whole sperm and the membrane potential change that occurs during the reaction.
Lievano
A
A
Sanchez
J A
JA
Darszon
A
A
D000177:Acrosome / Q000502:physiology; D000818:Animals; D002118:Calcium / Q000378:metabolism; D002463:Cell Membrane Permeability; D002712:Chlorides / Q000378:metabolism; D004553:Electric Conductivity; D004566:Electrodes; D004594:Electrophysiology; D006859:Hydrogen / Q000378:metabolism; D007473:Ion Channels / Q000502:physiology*; D008051:Lipid Bilayers / Q000502:physiology*; D008297:Male; D008564:Membrane Potentials; D011188:Potassium / Q000378:metabolism; D012617:Sea Urchins; D012964:Sodium / Q000378:metabolism; D013094:Spermatozoa / Q000166:cytology*; D013757:Tetraethylammonium Compounds / Q000494:pharmacology
D002712:Chlorides; D007473:Ion Channels; D008051:Lipid Bilayers; D013757:Tetraethylammonium Compounds; D006859:Hydrogen; D012964:Sodium; D011188:Potassium; D002118:Calcium