Ion channels in boar sperm plasma membranes: characterization of a cation selective channel.
Plasma membranes isolated from cauda epididymal and ejaculated boar sperm were inserted into planar lipid bilayers and examined for the presence of ion channels. Channel fusion was frequently observed; the most prominent was a nonselective cation channel which conducted K, Na, Cs, Ca, and Ba. Channel opening did not show a strict dependence on voltage but was partially blocked by verapamil, nitrendipine, and ruthenium red. A channel with these characteristics was observed when plasma membranes were isolated by high-pressure nitrogen cavitation (650 psi, 78% sperm head plasma membranes) or at very low nitrogen pressures (50 psi, 90% sperm head plasma membranes), suggesting that this channel may be present in the plasma membrane overlying the sperm head.
Cox
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Department of Physiology, School of Medicine, Southern Illinois University, Carbondale 62901.
Campbell
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Peterson
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D000818:Animals; D002413:Cations, Divalent / Q000378:metabolism*; D002414:Cations, Monovalent / Q000378:metabolism*; D002462:Cell Membrane / Q000737:chemistry* / Q000378:metabolism; D004822:Epididymis; D007473:Ion Channels / Q000187:drug effects / Q000378:metabolism*; D008051:Lipid Bilayers / Q000737:chemistry; D008297:Male; D008560:Membrane Fluidity / Q000187:drug effects / Q000502:physiology; D009568:Nitrendipine / Q000494:pharmacology; D012430:Ruthenium Red / Q000494:pharmacology; D013094:Spermatozoa / Q000737:chemistry* / Q000378:metabolism; D013552:Swine; D014700:Verapamil / Q000494:pharmacology
D002413:Cations, Divalent; D002414:Cations, Monovalent; D007473:Ion Channels; D008051:Lipid Bilayers; D012430:Ruthenium Red; D009568:Nitrendipine; D014700:Verapamil