Modulation of acid-sensing ion channels by Cu(2+) in cultured hypothalamic neurons of the rat

Neuroscience. 2007 Mar 16;145(2):631-41. doi: 10.1016/j.neuroscience.2006.12.009. Epub 2007 Jan 16.


Acid-sensing ion channels (ASICs) are known to distribute throughout the nervous system and serve important roles in various physiological and pathological processes. However, the properties of ASICs in the hypothalamus, an important region of diencephalon, are little known. We herein used whole-cell patch-clamp recordings to characterize proton-induced cation currents in cultured hypothalamic neurons of the rat, and attributed these transient inward currents to ASICs based on their electrophysiological and pharmacological properties. We further examined the effects of Cu(2+), the third most abundant trace element, on ASICs in hypothalamic neurons. Our results showed that this divalent cation reversibly and concentration-dependently inhibited the amplitude of ASIC currents, and slowed down the desensitization of ASIC channels. Our results also displayed that Cu(2+) modulated ASICs independent of change in membrane potential and extracellular protons, suggesting a noncompetitive mechanism. Furthermore, micromolar concentration of Cu(2+) attenuated the acid-induced membrane depolarization. Taken together, our data demonstrate a modulatory effect of Cu(2+) on ASICs in native hypothalamic neurons and suggest a role of this endogenous metal ion in negatively modulating the increased neuronal membrane excitability caused by activation of ASICs.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acid Sensing Ion Channels
  • Animals
  • Animals, Newborn
  • Cell Membrane / drug effects
  • Cell Membrane / metabolism*
  • Copper / metabolism*
  • Copper / pharmacology
  • Dose-Response Relationship, Drug
  • Extracellular Fluid / drug effects
  • Extracellular Fluid / metabolism
  • Hypothalamus / drug effects
  • Hypothalamus / metabolism*
  • Ion Channel Gating / drug effects
  • Ion Channel Gating / physiology
  • Membrane Potentials / drug effects
  • Membrane Potentials / physiology
  • Membrane Proteins / drug effects
  • Membrane Proteins / metabolism*
  • Nerve Tissue Proteins / drug effects
  • Nerve Tissue Proteins / metabolism*
  • Neurons / drug effects
  • Neurons / metabolism*
  • Organ Culture Techniques
  • Patch-Clamp Techniques
  • Rats
  • Rats, Wistar
  • Sodium Channels / drug effects
  • Sodium Channels / metabolism*


  • Acid Sensing Ion Channels
  • Membrane Proteins
  • Nerve Tissue Proteins
  • Sodium Channels
  • Copper