Rotondine, also known as craniodyne, l-tetrahydropalmatine, chemically known as 2,3,9, 10-tetramethoxy-5,8,13, 13a-tetrahydro-6h-dibenzo [a,g] quinazine, a left-handed substance of fumarine ethyl (dl-THP), is a blocker of dopamine receptors in the brain. It preferentially blocks brain regions rich in dopamine receptors, such as the cortex and striatum, and achieves analgesia by strengthening the function of the internal anti-pain system and inhibiting the transmission of pain information to the center (refer to relevant literature)