The membrane potential changes polarity during capacitation of murine epididymal sperm.
The membrane potential in murine epididymal sperm was determined with a voltage-sensitive, fluorescent probe. In freshly collected sperm, the potential was inside-negative, viz., -13 mV, and was associated with an intracellular K+ concentration of about 122 mM. Following incubation of sperm in a medium capable of sustaining capacitation and fertilization efficacy, the potential became gradually positive. An inside-positive potential, +24 mV, was obtained after 40 min of incubation, concomitant with an intracellular K+ concentration of approximately 30 mM. At this time, about 70 percent of sperm had capacitated. An inside-positive membrane potential may play a role in facilitating the acrosome reaction.
Chou
K
K
Department of Animal Science, Michigan State University, East Lansing 48824.
Chen
J
J
Yuan
S X
SX
Haug
A
A
D000818:Animals; D052160:Benzothiazoles; D002232:Carbocyanines; D002462:Cell Membrane / Q000502:physiology; D004822:Epididymis; D005456:Fluorescent Dyes; D007700:Kinetics; D008163:Luminescent Measurements; D008297:Male; D008564:Membrane Potentials; D051379:Mice; D008815:Mice, Inbred Strains; D013050:Spectrometry, Fluorescence; D013075:Sperm Capacitation; D013094:Spermatozoa / Q000502:physiology*
D052160:Benzothiazoles; D002232:Carbocyanines; D005456:Fluorescent Dyes; C012944:3,3'-dipropyl-2,2'-thiadicarbocyanine