Properties of voltage-gated currents of microglia developed using macrophage colony-stimulating factor

Pflugers Arch. 1995 Aug;430(4):526-33. doi: 10.1007/BF00373889.


Microglia were isolated from a murine neonatal brain cell culture in which their development had been stimulated by supplementation with the macrophage/microglial growth factor macrophage colony-stimulating factor (M-CSF). Using the whole-cell configuration of the patch-clamp technique, voltage-gated membrane currents were recorded from these microglial cells. Hyperpolarization induced inward rectifying K+ currents, as described for microglia from untreated cultures. These currents activated negative to the K+ equilibrium potential and, with a strong hyperpolarization, displayed time-dependent inactivation. The inactivation was abolished when extracellular NaCl was replaced by N-methyl-D-glucamine (NMG), thereby indicating a partial block of this K+ conductance by Na+. Inward rectifying currents were also blocked by extracellularly applied Cs+ or Ba2+. They were slightly diminished following treatment with extracellular tetraethylammonium chloride (TEA) but were not affected by 4-aminopyridine (4-AP). Upon long lasting depolarizing voltage pulses to potentials positive to 0 mV, the cells exhibited a slowly activating H+ current which could be reduced by application of inorganic polyvalent cations (Ba2+, Cd2+, Co2+, La3+, Ni2+, Zn2+) as well as by 4-AP or TEA. Based on their kinetics and pharmacological characteristics, both currents detected on M-CSF-grown microglia are suggested to correspond to the inward rectifier and the H+ current of macrophages.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Animals, Newborn
  • Barium / metabolism
  • Cations / metabolism
  • Cells, Cultured
  • Electrophysiology
  • Hydrogen-Ion Concentration
  • Ion Channel Gating / drug effects
  • Ion Channel Gating / physiology*
  • Ion Channels / drug effects
  • Ion Channels / physiology*
  • Macrophage Colony-Stimulating Factor / physiology*
  • Membrane Potentials / drug effects
  • Mice
  • Mice, Inbred C3H
  • Microglia / drug effects
  • Microglia / metabolism
  • Microglia / physiology*
  • Patch-Clamp Techniques
  • Potassium / physiology
  • Tetraethylammonium Compounds / pharmacology


  • Cations
  • Ion Channels
  • Tetraethylammonium Compounds
  • Barium
  • Macrophage Colony-Stimulating Factor
  • Potassium