title: [Blockade of magnesium sulfate on transient outward K+ current and delayed rectifier K+ current in acutely isolated rat hippocampal neurons].
abstract: OBJECTIVE
  To study the effect of magnesium sulfate on transient outward K+ current (IA) and delayed rectifier K+ current (IK) in freshly dissociated hippocampal neurons of rats.
  
  
  METHODS
  The whole-cell patch clamp techniques were used.
  
  
  RESULTS
  Magnesium sulfate reversibly reduced the amplitudes of IA and IK in a concentration-dependent and voltage-dependent, but not frequency-dependent manner. Half-blocking concentration (IC50) on IA and IK were 6.30 mmol.L-1 and 7.60 mmol.L-1, respectively. Magnesium sulfate (6 mmol.L-1) affected the activation process of IA and IK. Before and after application of the drug, the half-activation voltages of IA were (7 +/- 6) mV and (-7 +/- 11) mV (n = 10, P < 0.01), and the half-activation voltages of IK were (20 +/- 6) mV and (28 +/- 4) mV (n = 10, P < 0.01), but the slope factors were not changed. In addition, magnesium sulfate (6 mmol.L-1) also affected the inactivation process of IA. Before and after application of the drug, the half-inactivation voltages of IA were (-65 +/- 5) mV and (-89 +/- 6) mV (n = 10, P < 0.01).
  
  
  CONCLUSIONS
  Magnesium sulfate inhibited IA and IK in freshly dissociated hippocampal neurons of rats, which might contribute to protect the central neuronal system (CNS) against damages induced by ischemia and oxygen deprivation.
authors.affiliation: Institute of Environmental Medicine and Toxicology, Shanxi University, Taiyuan 030006, China.
authors.forename: Nan
authors.initials: N
authors.lastname: Sang
authors.forename: Zi-qiang
authors.initials: ZQ
authors.lastname: Meng
mesh_terms: D000818:Animals; D002469:Cell Separation; D051668:Delayed Rectifier Potassium Channels; D005260:Female; D006624:Hippocampus / Q000166:cytology*; D008278:Magnesium Sulfate / Q000494:pharmacology*; D008297:Male; D009474:Neurons / Q000187:drug effects* / Q000502:physiology; D018696:Neuroprotective Agents / Q000494:pharmacology*; D018408:Patch-Clamp Techniques; D015221:Potassium Channels / Q000187:drug effects / Q000378:metabolism*; D024642:Potassium Channels, Voltage-Gated; D051381:Rats; D017208:Rats, Wistar
chemical_list: D051668:Delayed Rectifier Potassium Channels; D018696:Neuroprotective Agents; D015221:Potassium Channels; D024642:Potassium Channels, Voltage-Gated; D008278:Magnesium Sulfate