Showing papers on "Sperm plasma membrane published in 1972"
TL;DR: The effect of a variety of agents upon the swimming speed of sea urchin spermatozoa was tested and strong positively-charged quaternary ammonium compounds had little affect on swim rate presumably because of their inability to penetrate the sperm plasma membrane.
Abstract: The effect of a variety of agents upon the swimming speed of sea urchin spermatozoa was tested. Some of the substances were those which influence membrane transport and transmission in excitable systems. The spermatozoa react intensely to small increases in environmental potassium; increasing potassium from 10 to 15 meq/liter slows the sperm by 30% while doubling the amount by addition of an equimolar amount of potassium chloride to the sea water medium reduces motility nearly 50%. Most of the other agents tested exerted a biphasic effect on swimming speed. While higher concentrations slowed the sperm lower concentratio ns speeded up descent to the bottom of the tube. 1 mM eserine sulfate a competitive inhibitor of acetylcholinesterase depressed motility about 40% while 1 mcgM accelerated it nearly 40% above control rate and 100 nM caused only about a 10% increase. Strong positively-charged quaternary ammonium compounds (tetraethylammonium neostigmine and acetylcholine) had little affect on swim rate presumably because of their inability to penetrate the sperm plasma membrane. Ouabain and eserine sulfate evoked a dose-dependent response. Sea urchin spermatozoa respond with extreme sensitivity to relatively small changes in external potassium but the spermatozoa are somewhat less affect in other species. Mytilus spermatozoa reportedly manifested no visible change in swimming behavior in the presence of various potassium levels. Arbacia (sea urchin) sperm motility determined by the change in optical density of centrifugally oriented suspensions averaged 187 mcm/second.
38 citations