Capsaicin activates a nonselective cation channel in cultured neonatal rat dorsal root ganglion neurons

Uhtaek Oh, Sun Wook Hwang, Donghee Kim

Research output: Contribution to journalArticle

185 Citations (Scopus)

Abstract

Capsaicin (CAP), a neurotoxin, has been reported to activate a nonselective cation current in dorsal root ganglion (DRG) neurons. In this paper, we identify and describe the properties of CAP-activated single channels in cultured neonatal rat DRG neurons. We first identified CAP- sensitive whole-cell currents that reversed near 0 mV in physiological solution. In solution containing 140 mM Na+, extracellular application of CAP to outside-out patches caused activation of an ion channel in a concentration-dependent manner (EC50 = 1.1 μM). The channel was blocked by the CAP antagonist capsazepine (10 μM). The channel was also activated by 2- 10 nM resiniferatoxin, a potent analog of CAP. In symmetrical 140 mM Na+, the single-channel slope conductances were 45.3 ± 1.0 and 80.0 ± 4.2 pS at -60 and +60 mV, respectively, showing outward rectification (n = 9). The reversal potential did not shift significantly when Na+ was replaced by K+, Cs+, Rb+, or Li+, showing that the channel discriminated poorly among cations. The channel was also permeable to Ca2+. Although acid (pH < 6.2) was suggested to be an endogenous activator of the CAP receptor, an acid solution (pH 5.9-6.0) tailed to activate the channels in outside-out patches. This is the first clear demonstration of the presence of the CAP-activated ion channel in DRG neuron. Opening of these ligand-gated, cation-selective channels gives rise to the whole-cell CAP-activated current in DRG neurons and may underlie the neurotoxic effects of CAP.

Original languageEnglish
Pages (from-to)1659-1667
Number of pages9
JournalJournal of Neuroscience
Volume16
Issue number5
Publication statusPublished - 1996 Mar 1
Externally publishedYes

Fingerprint

Capsaicin
Spinal Ganglia
Cations
Neurons
Ion Channels
TRPV Cation Channels
Acids
Neurotoxins
Ligands

Keywords

  • capsaicin
  • capsazepine
  • DRG
  • nonselective cation channel
  • pain
  • resiniferatoxin

ASJC Scopus subject areas

  • Neuroscience(all)

Cite this

Capsaicin activates a nonselective cation channel in cultured neonatal rat dorsal root ganglion neurons. / Oh, Uhtaek; Hwang, Sun Wook; Kim, Donghee.

In: Journal of Neuroscience, Vol. 16, No. 5, 01.03.1996, p. 1659-1667.

Research output: Contribution to journalArticle

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