[The Analgesia of Oxymatrine Affecting Calcium Channel and GABA Release].

Objective: To explore the analgesia of oxymatrine (OMT) affecting high voltage-dependent calcium channels (HVDCCs) and GABA release under neuropathic pain condition.

Methods: Totally 66 C57BL/6 mice were randomly divided into the sham-operation group, the model group, and the OMT group, 22 in each group. Neuropathic pain models were established by partial sciatic nerve ligation (PSNL). Hind paw plantar mechanical response threshold (MWT) was measured by up-and-down method with Von-Frey filament. mRNA expression of HVDCCs in brains and spinal cords was detected with Real-time PCR and concentration of GABA was determined using ELISA kit.

Results: Compared with day 0, the left hind paw MWTwas decreased on day 7, 10, and 14 in the model group (P < 0.05). Compared with the sham-operation group, the left hind paw MWT was significantly reduced in the model group on day 7 (P < 0.05). The MWT of PSNL ipsilateral hind paw was decreased on day 7 before OMT administration, when compared with day 0 (P < 0.05), and increased after OMT administration (P < 0.05). Compared with the sham-operation group, mRNA levels of Cav1.2, Cav1.3, Cav2.1, and Cav2.3 in brain tissues were increased and those of Cav2.2 were decreased significantly in the model group (P < 0.05). In spinal cord tissues, mRNA levels of Cav1.2 and Cav1.3 were increased, but those of Cav2.1, Cav2.2, and Cav2. 3 were decreased significantly in the model group, when compared with those of the sham-operation group (P < 0.05). Compared with the model group, mRNA levels of Cavl.2, Cavl.3, Cav2.1, and Cav2. 3 in brain tissues were decreased, and those of Cav2.2 were increased significantly in the OMT group (P < 0.05). In spinal cord tissues of the OMT group, mRNA levels of Cav1.3 decreased and those of Cav2.1, Cav2.2, and Cav2.3 increased significantly with statistical difference, when compared with those of the model group (P < 0.05). Compared with the sham-operation group, GABA levels in brain tissues decreased in the model group (P < 0.05). Compared with the model group, GABA levels in brain tissues increased in the OMT group (P < 0.05). There was no statistical difference in GABA levels of spinal cord tissues among these groups (P > 0.05).

Conclusions: OMT had analgesic effect on neuropathic pain, which might be probably related to HVDDCs. Cav2.2 might directly affect GABA release.