WARM CELLS REVEALED BY MICROFLUORIMETRY OF CA2-ROOT GANGLION NEURONS(IN CULTURED DORSAL)

Warm cells were identified by Fura-PES-based microfluorimetry of Ca2in cultured dorsal root ganglion (DRG) neurons. In response to a physi ologically relevant stimulus temperature (43 degrees C), a subpopulati on of small DRG neurons from new born rats increased the intracellular Ca2+ concentration ([Ca2+](i)). Seven percent of the cells responded to the warm stimulus. The stimulus evoked elevation in [Ca2+](i) from 52.5 +/- 9.5 nM (mean +/- S.D., n = 18) to 171.0 +/- 15.6 nM in cells between 15 and 25 mu m in diameter. The depletion of extracellular Ca2 + diminished the Ca2+ elevation. The Naf-free condition also diminishe d the response. We concluded that the heat stimulation opens nonselect ive cation channels in putative warm cells from DRG neurons. (C) 1998 Elsevier Science B.V. All rights reserved.