A novel type of cold-sensitive neuron in rat dorsal root ganglia with rapid adaptation to cooling stimuli.
Cold sensing in mammals is heterogeneous and more than one type of receptor molecule is likely to be involved in the transduction process. Most features of innocuous cold receptors have been explained by TRPM8, the cold and menthol receptor, but their fast adaptation to cooling has not yet been reproduced in cellular systems. In this study we have used a newly developed system for applying fast thermal stimuli to dissociated dorsal root ganglia (DRG) neurons from young rats (150-200 g) in primary culture. We describe a novel type of cold-sensitive rat DRG neuron with rapid adaptation to cooling. These cells (4.3% of the total DRG population) do not express either TRPM8 or the other cold-activated TRP channel, TRPA1, and the epithelial sodium channel (ENaC) is not involved in their transduction. Increases in intracellular calcium induced by cooling in rapidly adapting neurons are caused by calcium entry. These neurons express a large and rapidly adapting cold-induced inward current with a time constant of adaptation in the seconds range, and may correspond to the rapidly adapting cold receptors described in vivo.
Babes
Alexandru
A
Department of Animal Physiology and Biophysics, Faculty of Biology, University of Bucharest, Splaiul Independentei 91-95, Bucharest, Romania. babes@physiologie1.uni-erlangen.de
Zorzon
Daniel
D
Reid
Gordon
G
D000222:Adaptation, Physiological / Q000502:physiology; D000584:Amiloride / Q000494:pharmacology; D000818:Animals; D017487:Ankyrins; D015220:Calcium Channels / Q000187:drug effects / Q000378:metabolism; D020013:Calcium Signaling / Q000187:drug effects / Q000502:physiology; D002164:Camphor / Q000494:pharmacology; D002478:Cells, Cultured; D003080:Cold Temperature; D005727:Ganglia, Spinal / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D008610:Menthol / Q000494:pharmacology; D009475:Neurons, Afferent / Q000187:drug effects / Q000378:metabolism*; D018408:Patch-Clamp Techniques; D051381:Rats; D017208:Rats, Wistar; D000074025:TRPA1 Cation Channel; D050052:TRPC Cation Channels; D050053:TRPM Cation Channels / Q000378:metabolism; D050916:TRPV Cation Channels / Q000378:metabolism; D013697:Thermosensing / Q000502:physiology*; D013997:Time Factors
D017487:Ankyrins; D015220:Calcium Channels; D000074025:TRPA1 Cation Channel; D050052:TRPC Cation Channels; D050053:TRPM Cation Channels; D050916:TRPV Cation Channels; C480976:Trpa1 protein, rat; C498947:Trpm8 protein, rat; C493922:Trpv1 protein, rat; D008610:Menthol; D002164:Camphor; D000584:Amiloride