Thermal sensitivity of voltage-gated Na+ channels and A-type K+ channels contributes to somatosensory neuron excitability at cooling temperatures.
Cooling temperatures may modify action potential firing properties to alter sensory modalities. Herein, we investigated how cooling temperatures modify action potential firing properties in two groups of rat dorsal root ganglion (DRG) neurons, tetrodotoxin-sensitive (TTXs) Na(+) channel-expressing neurons and tetrodotoxin-resistant (TTXr) Na(+) channel-expressing neurons. We found that multiple action potential firing in response to membrane depolarization was suppressed in TTXs neurons but maintained or facilitated in TTXr neurons at cooling temperatures. We showed that cooling temperatures strongly inhibited A-type K(+) currents (IA) and TTXs Na(+) channels but had fewer inhibitory effects on TTXr Na(+) channels and non-inactivating K(+) currents (IK). We demonstrated that the sensitivity of A-type K(+) channels and voltage-gated Na(+) channels to cooling temperatures and their interplay determine somatosensory neuron excitability at cooling temperatures. Our results provide a putative mechanism by which cooling temperatures modify different sensory modalities including pain.
Department of Anesthesiology and the Graduate Program in Neuroscience, The University of Cincinnati College of Medicine, Cincinnati, OH, USA.
Ignacio
I
Sarria
Jennifer
J
Ling
Jianguo G
JG
Gu
D000818:Animals; D002478:Cells, Cultured; D003080:Cold Temperature / Q000009:adverse effects*; D005260:Female; D008297:Male; D010146:Pain / Q000209:etiology / Q000378:metabolism / Q000503:physiopathology; D026902:Potassium Channel Blockers / Q000494:pharmacology; D024642:Potassium Channels, Voltage-Gated / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D011984:Sensory Receptor Cells / Q000166:cytology / Q000378:metabolism / Q000502:physiology*; D026941:Sodium Channel Blockers / Q000494:pharmacology; D015222:Sodium Channels / Q000378:metabolism*; D013779:Tetrodotoxin / Q000494:pharmacology
D026902:Potassium Channel Blockers; D024642:Potassium Channels, Voltage-Gated; D026941:Sodium Channel Blockers; D015222:Sodium Channels; D013779:Tetrodotoxin