Calcium antagonists ameliorate ischemia-induced endothelial cell permeability by inhibiting protein kinase C

Circulation. 1999 May 18;99(19):2523-9. doi: 10.1161/01.cir.99.19.2523.


Background: Dihydropyridines block calcium channels; however, they also influence endothelial cells, which do not express calcium channels. We tested the hypothesis that nifedipine can prevent ischemia-induced endothelial permeability increases by inhibiting protein kinase C (PKC) in cultured porcine endothelial cells.

Methods and results: Ischemia was induced by potassium cyanide/deoxyglucose, and permeability was measured by albumin flux. Ion channels were characterized by patch clamp. [Ca2+]i was measured by fura 2. PKC activity was measured by substrate phosphorylation after cell fractionation. PKC isoforms were assessed by Western blot and confocal microscopy. Nifedipine prevented the ischemia-induced increase in permeability in a dose-dependent manner. Ischemia increased [Ca2+]i, which was not affected by nifedipine. Instead, ischemia-induced PKC translocation was prevented by nifedipine. Phorbol ester also increased endothelial cell permeability, which was dose dependently inhibited by nifedipine. The effects of non-calcium-channel-binding dihydropyridine derivatives were similar. Analysis of the PKC isoforms showed that nifedipine prevented ischemia-induced translocation of PKC-alpha and PKC-zeta. Specific inhibition of PKC isoforms with antisense oligodeoxynucleotides demonstrated a major role for PKC-alpha.

Conclusions: Nifedipine exerts a direct effect on endothelial cell permeability that is independent of calcium channels. The inhibition of ischemia-induced permeability by nifedipine seems to be mediated primarily by PKC-alpha inhibition. Anti-ischemic effects of dihydropyridine calcium antagonists could be due in part to their effects on endothelial cell permeability.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Calcium Channel Blockers / pharmacology*
  • Capillary Permeability / drug effects*
  • Cells, Cultured
  • Endothelium, Vascular / drug effects
  • Endothelium, Vascular / metabolism*
  • Endothelium, Vascular / pathology*
  • Ischemia*
  • Nifedipine / pharmacology*
  • Poisons / toxicity
  • Potassium Cyanide / toxicity
  • Protein Kinase C / antagonists & inhibitors*
  • Swine


  • Calcium Channel Blockers
  • Poisons
  • Protein Kinase C
  • Nifedipine
  • Potassium Cyanide