Table 1.

Summary of ionic current signatures in different subpopulations of acutely dissociated sensory neurons

Isolated DRG soma diameter (µm)	Sensory fibre type	ITCa2+-current density	IHVACa2+- current density	INa+TTX-R-current density	ITRPV1-current density	Threshold for mechano-sensory currents	Expression of IB4 imuno	Presumed function In vivo
Small 15–25	C-type Classic	++	++++	++++	++++	High	++	Nociceptive
Small 26–31	C-type T-rich	++++	None	++++	++	High	+++	Nociceptive
Medium 32–45	A-δ	++	++++	++++	++++	n.a.	++++	Nociceptive
Medium 32–45	D-hair	++++	++	+	None	Low	n.a.	Mechanosensory
Large >45	A-α/β	++	++++	+	None	Low	None	Mechanosensory

Data are based on the following references: Nelson et al. (2005), Jagodic et al. (2007), Coste et al. (2007) and Wu et al. (2004). Note that T-currents are expressed in three subpopulations of putative nociceptive and two subpopulations of putative mechanosensory non-nociceptive neurons.

++++, very high; +++, high; ++, moderate; +, low; n.a., not applicable; I_TCa²⁺, T-type Ca²⁺ currents; I_HVACa²⁺, high-voltage-activated Ca²⁺ currents; I_Na⁺_TTX-R, tetrodotoxin-resistant voltage-gated Na⁺ currents; I_TRPV1, transient receptor potential vanilloid 1 (capsaicin-gated) currents; IB₄, isolectin B₄; DRG, dorsal root ganglion.