Sensory discrimination between innocuous and noxious cold by TRPM8-expressing DRG neurons of rats

Molecular Pain

Table 1 Membrane parameters of TTXs/TRPM8 and TTXr/TRPM8 DRG neurons

Cell type	RMP (mV)	Threshold (mV)	AP width (W _1/2,ms)	AHP amplitude (mV)	AHP peak (mV)	Input R (MΩ)
TTXs/TRPM8 n = 12	−51.7 ± 0.7	−30.9 ± 1.4†	3.5 ± 0.2†	15.4 ±1.0†	−46.2 ± 1.1	437 ± 71
TTXr/TRPM8 n = 11	−51.0 ± 1.3	−19.3 ± 2.0	4.9 ± 0.4	25.8 ± 1.5	−45.1 ± 1.4	535 ± 35

Cells were pre-identified by the Ca²⁺ imaging method for their cold- and menthol-sensitivity and by voltage-clamp recording for the sensitivity of voltage-activated Na⁺ channel currents to 500 nM TTX. TTXs/TRPM8: TTXs cells that are sensitive to menthol and cold; TTXr/TRPM8: TTXr cells that are sensitive to menthol- and cold. Cells were then under current-clamp configuration and experiments were performed at 24°C. RMP: resting membrane potential; AP: action potential; AHP: afterhyperpolarization; R: resistant. Data represent mean ± SEM. † P < 0.05, TTXs/TRPM8 vs. TTXr/TRPM8.

ISSN: 1744-8069