Capsaicin activates a nonselective cation channel in cultured neonatal rat dorsal root ganglion neurons
抄録
<jats:p>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 microM). The channel was blocked by the CAP antagonist capsazepine (10 microM). 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) failed 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.</jats:p>
収録刊行物
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- The Journal of Neuroscience
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The Journal of Neuroscience 16 (5), 1659-1667, 1996-03-01
Society for Neuroscience
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詳細情報 詳細情報について
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- CRID
- 1360011145183537536
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- ISSN
- 15292401
- 02706474
- http://id.crossref.org/issn/02706474
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- データソース種別
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- Crossref