Table 1.

Ca²⁺ transients in subpopulations of small-diameter DRG neurons

Subpopulation	n	Δ[Ca2+]i (nm)	T50 (s)
IB4+	96	445 ± 52	12.4 ± 0.9**
IB4−	31	416 ± 21	6.2 ± 0.5
CAP+	85	395 ± 19*	10.8 ± 0.9
CAP−	42	482 ± 45	11.1 ± 1.3
IB4+/CAP+	65	397 ± 20	12.0 ± 1.2
IB4+/CAP−	31	458 ± 50	13.2 ± 1.6
IB4−/CAP+	20	390 ± 57	6.7 ± 0.7
IB4−/CAP−	11	548 ± 97	5.2 ± 0.7

The magnitude (Δ[Ca²⁺]_i) and decay (T₅₀) of high-K⁺-evoked Ca²⁺ transients were analysed in subpopulations of small-diameter (i.e. < 30 μm) DRG neurons. Subpopulations were defined by IB₄ binding, capsaicin (CAP) sensitivity, or the combination of the two and differences between groups (i.e. IB₄+versus IB_4–) were assessed. The decay of evoked Ca²⁺ transients was significantly

^**P < 0.01 slower in IB₄+ neurons than in IB_4– neurons. The magnitude of the evoked Ca²⁺ transient was significantly

^*P < 0.05 smaller in CAP+ neurons than that in CAP– neurons. There was a significant (P < 0.01) group effect in the decay of evoked Ca²⁺ transients when subpopulations defined by the combination of IB₄ binding and CAP sensitivity were compared. Post hoc analysis indicated that the decay of the transient in IB₄+/CAP– neurons was significantly slower than that in IB_4–/CAP+ (P < 0.05) and IB_4–/CAP– neurons (P < 0.05). There were no other significant differences between groups.