Fig. 5.

Noxious stimulation applied to the somatic area where referred mechanical sensitivity develops after MI increases SNA and HR. A Schematic (left) and experimental protocol (right) of electrophysiological recording of SNA and VNA in MI rats. Peripheral non-noxious (brush) or noxious stimuli [pinch, 3-mA electrical stimulation (ES), noxious heat (48°C)] applied either to the sensitized (PC6 in the forearm) or unsensitized (SP6 in the hindlimb) areas in MI rats. B Representative traces of SNA, VNA, and HR in MI rats before (baseline) and after stimulation applied to the sensitized and unsensitized areas. C–E Frequencies of SNA (C), VNA (D) ,and HR (E) before and after stimulation (n = 4–6/group; *P <0.05, **P <0.01 vs baseline; ^#P <0.05, ^##P <0.01 vs sensitized area). Two-way ANOVA with Bonferroni test was used to compare groups, and the paired t-test was used to compare sensitized and non-sensitized areas in C–E.