Potassium currents recorded in type I carotid body cells from the neonatal rat and their modulation by chemoexcitatory agents

Brain Res. 1990 Jul 9;522(2):259-66. doi: 10.1016/0006-8993(90)91470-2.


Whole cell patch clamp recordings were made from type I cells of the neonatal rat carotid body, isolated and maintained in primary culture for up to 48 h. Depolarizing voltage steps applied from a holding potential of -70 mV evoked outward currents positive to approximately -30 mV. Currents were strongly blocked by extracellular tetraethylammonium (25 mM), and were therefore attributed to activation of voltage-dependent K+ channels. Currents were also suppressed by 4-aminopyridine, removal of extracellular Ca2+, and replacement of extracellular Ca2+ with Ba2+. These results suggest there are Ca2(+)-dependent and Ca2(+)-independent components of the K+ currents. No evidence was found to suggest that ATP-sensitive K+ channels were present. The effects of 3 chemoexcitatory agents (NaCN, almitrine and reduced extracellular pH) on K+ currents in isolated type I cells were investigated. All three agents suppressed K+ currents to similar degrees. The effects of lowered pH and NaCN were reversible, and NaCN-induced reductions occurred regardless of the presence of intracellular ATP. The effect of almitrine was irreversible for up to 30 min of recording. It is concluded that the reduction of K+ currents by chemoexcitants may play a role in the mechanism of chemotransduction in the carotid body.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenosine Triphosphate / pharmacology
  • Almitrine / pharmacology
  • Animals
  • Animals, Newborn / physiology*
  • Carotid Body / drug effects
  • Carotid Body / physiology*
  • Carotid Body / ultrastructure
  • Hydrogen-Ion Concentration
  • Microscopy, Electron
  • Potassium Channels / drug effects
  • Potassium Channels / physiology*
  • Rats
  • Rats, Inbred Strains
  • Sodium Cyanide / pharmacology


  • Potassium Channels
  • Adenosine Triphosphate
  • Almitrine
  • Sodium Cyanide