Table 3.

Effects of locally applied lignocaine on the amplitude and time course of the NTIs recorded from polymodal and cold-sensitive receptors

	n	+Peak	−Peak	+dV/dt max(normalized)	−dV/dt max(normalized)	Ratio
Polymodal(electrically evoked)
Hepes	6	0.96 ± 0.04	0.94 ± 0.05	1.04 ± 0.05	1.04 ± 0.10	1.02 ± 0.16
2.5 mM lignocaine	7	0.87 ± 0.06*	0.98 ± 0.24	0.86 ± 0.04*	0.75 ± 0.04**	1.30 ± 0.15
20mM lignocaine	6	0.80 ± 0.09*	0.67 ± 0.05**†	1.21 ± 0.19	0.56 ± 0.07**†	2.28 ± 0.47*†
Cold (spontaneous)
Hepes	7	0.99 ± 0.04	0.95 ± 0.04	1.13 ± 0.07	1.16 ± 0.09	0.99 ± 0.06
2.5 mM lignocaine	9	0.92 ± 0.04*	0.81 ± 0.07*	0.93 ± 0.05	0.91 ± 0.07	1.12 ± 0.11
20mM lignocaine	7	0.77 ± 0.06**†	0.75 ± 0.10*	0.96 ± 0.05	1.09 ± 0.15	0.98 ± 0.13

^*All values are the mean ±s.e.m. of the test values expressed relative to the control values. Prior to calculating the relative change in the maximum rates (V s⁻¹) of rise and fall, the values were normalized with respect to NTI amplitude by dividing them by the peak-positive amplitude (see Methods). The ratio was calculated by dividing +dV/dt max by −dV/dt max. Statistical comparisons between control and test values were made using one-sided, paired t tests (P < 0.05)

^**All values are the mean ±s.e.m. of the test values expressed relative to the control values. Prior to calculating the relative change in the maximum rates (V s⁻¹) of rise and fall, the values were normalized with respect to NTI amplitude by dividing them by the peak-positive amplitude (see Methods). The ratio was calculated by dividing +dV/dt max by −dV/dt max. Statistical comparisons between control and test values were made using one-sided, paired t tests (P < 0.01).

^†Statistical comparisons between the effects of 2.5 and 20mM lignocaine on NTIs were made using unpaired t tests (P < 0.05).