Central and Peripheral Mechanism of Acupuncture Analgesia on Visceral Pain: A Systematic Review

Figure 3

Schematic illustration of functional and metabolic changes (peptides, proteins, and mRNA) of the brain-gut axis by acupuncture in visceral pain studies. In human, acupuncture consistently enhanced the functional activity in the thalamus and insula, the core brain regions of pain processing. In animal, a great variety of metabolic changes have been reported as well as functional neural activities, demonstrating that acupuncture induces a wide range of changes through the brain-gut axis in visceral pain. ACC: anterior cingulate cortex; AMG: amygdala; CC: central canal; DH: dorsal horn; DRG: dorsal root ganglion; DRN: dorsal raphe nucleus; HyTH: hypothalamus; INS: insula; MED: medulla; NR2B: N-methyl-D-aspartate receptor subunit; PAG: periaqueductal gray; PFC: prefrontal cortex; P2X3: P2X purinoceptor 3; SC: somatosensory cortex; sub P: substance P; TH: thalamus; 4th V: fourth ventricle.