A: Representative photographs of a coronal section showing SP expression in the spinal cord. Photographs (200 ×) illustrate SP immunoreactive neurons in the mouse superficial dorsal horn (SDH) of L3–5 levels. (a) Control, (b) Tumor control, (c) EA treated group. Arrows indicate SP positive cells. B&C: EA treatment increased the level of β-endorphin in blood and brain compared to untreated tumor control. B: level of β-endorphin in blood C: level of β-endorphin in brain. Values of β-endorphin are expressed as means ± SE. Different superscripts(a, b, c) indicate p < 0.05 statistical significance between groups using ANOVA test-Turkey's procedure.