title: [Effect of the Ca2+ -activated K+ channel in veratridine-induced cortex neurons damage].
abstract: OBJECTIVE
  To observe the effects of Ca2+ -activated K+ channel of primary cultured fetal SD rat cortex neurons in the veratridine triggered neuronal damage.
  
  
  METHODS
  The patch clamp technique of cell-attach and inside-out mode for these two kinds of single channel recordings were used.
  
  
  RESULTS
  Extracellular veratridine activated the Kca. In Ca2+ bath solution of cell-attach mode, Vp + 30 mV, when the concentration (micromol/L) of veratridine were 15,25,50 and 75, the open probabilities of the channel were 0.014 +/- 0.003, 0.085 +/- 0.010, 0.132 +/- 0.016 and 0.059 +/- 0.006 (P < 0.01) respectively. It appeared concentration-dependent within 50 micromol/L veratridine. In Ca2+ free bath solution of cell-attach mode, Vp = +50 mV, when the concentration (micromol/L) of veratridine were 15, 40,60 and 100, the open probabilities of the channel were 0.014 +/- 0.010, 0.113 +/- 0.006, 0.141 +/- 0.004 and 0.295 +/- 0.009 (P < 0.05) respectively. In the 6 cases of inside-out mode patch clamp, Vp = +40 mV, when the concentration of veratridine were 0, 25 micromol/L and 50 micromol/L, the open probabilities of the channel were 0.011 +/- 0.008, 0.010 +/- 0.010 and 0.012 +/- 0.007 (P > 0.05) respectively. There were no significant difference on open probabilities, average open/close times and amplitudes at different intracellular veratridine concentration.
  
  
  CONCLUSIONS
  Veratridine can affect the activation of the Kca channel through regulating the concentration of cytoplasmic free Ca2+. The opening of Kca activated by increase of intracellular Ca2+ during the early stage of anoxia may be a protection reaction of ischemic neurons.
authors.affiliation: West China Hospital of Sichuan University, Chengdu 610041, China.
authors.forename: Xiao-hui
authors.initials: XH
authors.lastname: Lai
authors.forename: Gang
authors.initials: G
authors.lastname: Xu
authors.forename: Wen-mei
authors.initials: WM
authors.lastname: Zhu
authors.forename: Guang-gu
authors.initials: GG
authors.lastname: Yuan
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D002118:Calcium / Q000378:metabolism; D002478:Cells, Cultured; D009474:Neurons / Q000166:cytology / Q000187:drug effects* / Q000502:physiology*; D018408:Patch-Clamp Techniques; D024681:Potassium Channels, Calcium-Activated / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D014701:Veratridine / Q000494:pharmacology*
chemical_list: D024681:Potassium Channels, Calcium-Activated; D014701:Veratridine; D002118:Calcium