title: A patch-clamp study on human sperm Cl- channel reassembled into giant liposome.
abstract: OBJECTIVE
  To record the single-channel currents and characterize the electrophysiological properties of the Cl- channels in human sperm membrane.
  
  
  METHODS
  The membrane proteins extracted from the human sperm were reassembled into liposome bilayer, and the liposomes were fused into giant liposomes with a diameter more than 10 microm by dehydration-rehydration procedure. The giant liposomes were used to study the Cl- channel activities by patch-clamp technique.
  
  
  RESULTS
  By patch clamping the giant liposome in an asymmetric NMDG (N-methyl-D-glucamine)-Cl (bath 100// pipette 200 mmol/L) solution system, three kinds of single-channel events with unit conductances of (74.1 +/- 8.3) pS, (117.0 +/- 5.7) pS and (144.7 +/- 4.5) pS, respectively, were detected. Their activities were voltage-dependent and all were blocked by SITS (4-acetamido-4'-isothiocyanato-stilbene-2', 2'-disulfonic acid) in a concentration-dependent manner. By constructing the open and close dwell time distribution histograms and then fitting them with exponential function, two time constants were obtained in both the open and the close states. The burst activity and conductance substate of the channels were observed.
  
  
  CONCLUSIONS
  There exist three kinds of Cl- channels with different conductance in human sperm membrane at least.
authors.affiliation: Key Laboratory of Neurobiology, Institute of Physiology,  Chinese Academy of Sciences, Shanghai.
authors.forename: J P
authors.initials: JP
authors.lastname: Bai
authors.forename: Y L
authors.initials: YL
authors.lastname: Shi
mesh_terms: D012856:4-Acetamido-4'-isothiocyanatostilbene-2,2'-disulfonic Acid / Q000494:pharmacology; D000328:Adult; D018118:Chloride Channels / Q000037:antagonists & inhibitors / Q000502:physiology*; D006801:Humans; D015640:Ion Channel Gating / Q000502:physiology; D008081:Liposomes / Q000378:metabolism; D008297:Male; D008564:Membrane Potentials / Q000187:drug effects / Q000502:physiology; D008565:Membrane Proteins / Q000502:physiology; D008875:Middle Aged; D018408:Patch-Clamp Techniques; D010507:Periodicity; D013094:Spermatozoa / Q000502:physiology*
chemical_list: D018118:Chloride Channels; D008081:Liposomes; D008565:Membrane Proteins; D012856:4-Acetamido-4'-isothiocyanatostilbene-2,2'-disulfonic Acid