Inhibition of different pathways influencing Na(+) homeostasis protects organotypic hippocampal slice cultures from hypoxic/hypoglycemic injury

Neuropharmacology. 2000 Jul 24;39(10):1779-87. doi: 10.1016/s0028-3908(00)00027-7.


A prominent feature of cerebral ischemia is the excessive intracellular accumulation of both Na(+) and Ca(2+), which results in subsequent cell death. A large number of studies have focused on pathways involved in the increase of the intracellular Ca(2+) concentration [Ca(2+)](i), whereas the elevation of intracellular Na(+) has received less attention. In the present study we investigated the effects of inhibitors of different Na(+) channels and of the Na(+)/Ca(2+) exchanger, which couples the Na(+) to the Ca(2+) gradient, on ischemic damage in organotypic hippocampal slice cultures. The synaptically evoked population spike in the CA1 region was taken as a functional measure of neuronal integrity. Neuronal cell death was assessed by propidium iodide staining. The Na(+) channel blocker tetrodotoxin, and the NMDA receptor blocker MK 801, but not the AMPA/kainate receptor blocker NBQX prevented ischemic cell death. The novel Na(+)/Ca(2+) exchange inhibitor 2-[2-[4-(4-nitrobenzyloxy)phenyl]ethyl]isothiourea methanesulfonate (KB-R7943), which preferentially acts on the reverse mode of the exchanger, leading to Ca(2+) accumulation, also reduced neuronal damage. At higher concentrations, KB-R7943 also inhibits Ca(2+) extrusion by the forward mode of the exchanger and exaggerates neuronal cell death. Neuroprotection by KB-R7943 may be due to reducing the [Ca(2+)](i) increase caused by the exchanger.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Brain Ischemia / physiopathology
  • Cell Death
  • Culture Techniques
  • Dizocilpine Maleate / pharmacology
  • Electrophysiology
  • Hippocampus / metabolism*
  • Hippocampus / pathology
  • Hippocampus / physiopathology
  • Homeostasis
  • Hypoglycemia / physiopathology*
  • Hypoxia / physiopathology*
  • Neurons / drug effects
  • Neurons / pathology
  • Quinoxalines / pharmacology
  • Rats
  • Rats, Wistar
  • Receptors, AMPA / antagonists & inhibitors
  • Receptors, AMPA / physiology
  • Receptors, Kainic Acid / antagonists & inhibitors
  • Receptors, Kainic Acid / physiology
  • Receptors, N-Methyl-D-Aspartate / antagonists & inhibitors
  • Receptors, N-Methyl-D-Aspartate / physiology
  • Sodium / metabolism*
  • Sodium Channel Blockers
  • Sodium Channels / physiology
  • Sodium-Calcium Exchanger / antagonists & inhibitors
  • Tetrodotoxin / pharmacology
  • Thiourea / analogs & derivatives
  • Thiourea / pharmacology


  • 2-(2-(4-(4-nitrobenzyloxy)phenyl)ethyl)isothiourea methanesulfonate
  • Quinoxalines
  • Receptors, AMPA
  • Receptors, Kainic Acid
  • Receptors, N-Methyl-D-Aspartate
  • Sodium Channel Blockers
  • Sodium Channels
  • Sodium-Calcium Exchanger
  • 2,3-dioxo-6-nitro-7-sulfamoylbenzo(f)quinoxaline
  • Tetrodotoxin
  • Dizocilpine Maleate
  • Sodium
  • Thiourea