title: Ca2+ is essential for the motility of plasma membrane-intact, but not of demembranated, hamster spermatozoa.
abstract: Extracellular Ca2+ is essential for the flagellar motility of membrane-intact hamster spermatozoa. When suspended in a medium completely free of Ca2+, most spermatozoa quickly lost their motility, and remained motionless until they were transferred back to Ca2+-containing medium. The motility could not be restored after the spermatozoa had been in Ca2+-free medium for more than 2 hr. Unlike membrane-intact spermatozoa, demembranated spermatozoa (spermatozoa without plasma membranes) exhibited active movement in Ca2+-free medium, and their motility was inhibited by Ca2+. In view of these facts, we suggest that the "hyperactivated motility" which membrane-intact spermatozoa display upon capacitation may be due to the activation of a Ca2+-dependent adenylate cyclase (and the resultant increase in intracellular cAMP), rather than being a direct effect of a rise in the intracellular Ca2+ concentration.
authors.affiliation: Department of Anatomy, University of Hawaii, Honolulu.
authors.forename: B
authors.initials: B
authors.lastname: Feng
authors.forename: A
authors.initials: A
authors.lastname: Bhattacharyya
authors.forename: R
authors.initials: R
authors.lastname: Yanagimachi
mesh_terms: D000818:Animals; D002118:Calcium / Q000502:physiology*; D002462:Cell Membrane / Q000502:physiology*; D006224:Cricetinae; D008297:Male; D013081:Sperm Motility; D013094:Spermatozoa / Q000502:physiology*
chemical_list: D002118:Calcium