Figure 5

HC-030031 has no effect on mechanical firing in A fiber nociceptors. A) Example of an A-mechanoreceptor from rat responding to increasing sustained force (40 mN, 100 mN, 150 mN; 10 sec each) after a 10 min incubation of the receptive field with either vehicle (1% DMSO; top; conduction velocity: 8.65 m/s; von Frey threshold: 11.7 mN) or HC-030031 (100 μM; bottom; conduction velocity: 6.27 m/s; von Frey threshold: 14.6 mN). Action potential waveform is shown at the right of each trace. B) Average number of action potentials evoked per second in A-mechanoreceptors by a 10 sec, sustained mechanical force applied in increasing intensities in the presence of vehicle (solid squares) or HC-030031 (100 μM open circles). Y-axis bars represent the SEM for each mean data point. HC-030031 had no effect on the mechanical firing rate of A-mechanoreceptors at any stimulus intensity (p > 0.05; 2-way repeated measures ANOVA). C) Adaptation rate of action potential firing in A-mechanoreceptors during a 10 sec, 100 mN mechanical force in the presence of vehicle (black bars) or HC-030031 (100 μM; grey bars). HC-030031 had no effect on the adaptation rate (p > 0.05, 2-way ANOVA).