Electroacupuncture intervention relieves pain possibly by promoting MOR endocytosis in locus coeruleus in bone cancer pain rats with morphine tolerance

• Published in: Zhēncì yánjiū Vol. 44; no. 3; p. 161
• Main Authors: Shi, Ren-Yi, Fu, Tao-Fang, Cai, Yang-Qian, Du, Jun-Ying, Fang, Jun-Fan, Fang, Jian-Qiao, Liang, Yi
• Format: Journal Article
• Language: Chinese
• Published: China 25.03.2019
• Subjects: Morphine tolerance; µ-opioid receptor; Locus coeruleus (LC); Electroacupuncture; Bone cancer pain; Endocytosis of receptor
• ISSN: 1000-0607
• DOI: 10.13702/j.1000-0607.180635

To observe the effect of electroacupuncture (EA) on pain behavior and expression of µ-opioid receptor (MOR) and Rab5 (an important protein molecule for internalization of MOR) in the locus coeruleus (LC) region in bone cancer pain (BCP) rats with morphine tolerance (MT), so as to explore its mechanisms underlying improvement of BCP and MT. The present study included two parts. In the first part, 23 female SD rats were randomized into sham BCP ( ＝6), BCP ( ＝9) and BCP＋MT ( ＝8) groups, and in the second part, 61 female SD rats were randomized into 5 groups: sham BCP ( ＝11), BCP ( ＝11), BCP＋MT ( ＝13), BCP＋MT＋EA ( ＝13) and BCP＋MT＋sham EA ( ＝13). The BCP morphine tolerance (BCP＋MT) model was established by injection of 10 µL of human Walker 256 breast cancer cells (MRMT-1 breast cancer cells, 1 x10 cells/µL) into the bone marrow cavity at the upper part of the left tibia and intraperitoneal injection of morphine hydrochloride (10 mg/kg, once per 12 h, for 11 successive days). On day 21 after inoculation, EA (2 Hz/