Effects of chemical labyrinthectomy on stress analgesia induced by rotation in mice / 药学实践杂志

ABSTRACT

Objective To investigate the role of vestibular organs on stress analgesia induced by rotation in mice. Methods Female mice were randomly divided into morphine group and rotation group. After 15 minutes of intraperitoneal injection of naloxone or normal saline, the hot plate latency of mice in each group was observed following morphine injection or rotation (250 r/min, 15 s on with 5 s off). After subcutaneous injecting morphine for 7 consecutive days, tolerance was formed and the hot plate latency in morphine-tolerant mice after rotation was observed. P-aminophenylarsonic acid was injected into the inner ear to damage the vestibular organs of the mice and the hot plate latency was observed in chemically labyrinthectomy mice. Results Compared with the normal saline group, the hot plate latency of mice in the naloxone group did not change significantly after rotation (P>0.05), and the hot plate latency decreased significantly after subcutaneous injection of morphine (P<0.05). The morphine-tolerant mice had no significant change in the hot plate latency after rotation compared with the normal saline group (P>0.05). After injection of p-aminophenylarsonic acid into the inner ear, the recovery time of the righting reflex in mice was significantly increased, and the swimming ability was significantly reduced (P<0.05), and the hot plate latency of mice with chemical labyrinthectomy was significantly shortened after rotation (P<0.05). Conclusion Chemical labyrinthectomy completely blocked the rotation-induced stress analgesia in mice. Vestibular organs play an important role in rotation-induced stress analgesia, and this stress analgesia may be mediated by a non-opioid system.