Fig. 4

2R, 6R-HNK reverses the activation of several brain nuclei induced by LF-PENS. a Schematic diagram of nuclei of interest in brain slices. ACC: Amy: amygdala; Pir: piriform cortex; LHb, lateral habenular nucleus; VMH: ventromedial nucleus of hypothalamus; DM: dorsomedial hypothalamic nucleus. b-c Representative images and quantification of the number of c-Fos⁺, p-CREB⁺ or p-ERK⁺ cells showing that 2R, 6R-HNK pretreatment suppressed the increases in their expression in the bilateral Amy, Pir, LHb, VMH or DM at 3 h after LF-PENS. d-e Representative images and quantification of the number of p-ERK⁺ cells indicating that multiple 2R, 6R-HNK appliance suppressed the increases of neuron excitability markers’ expression in bilateral ACC, Pir and VMH at 30 d (n = 5 mice/group, 4 sections/mouse), ^*p < 0.05, ^**p < 0.01, ^***p < 0.001, ^****p < 0.0001 between groups