Effects of L-type calcium channel blockers on tramadol-induced analgesia in mice / 中国药理学通报

ABSTRACT

Aim To investigate the effects of L-type calcium channel blockers on tramadol-induced analgesia.Methods Hot-plate test and writhing test were used to measure the analgesia induced by tramadol. Verapamil, nimodipine or nifedipine was co-administrated with tramadol to determine its effects on tramadol analgesia.Results Tramadol (10, 20, 40 mg?kg -1 in hot-plate test or 2, 5,10 mg?kg -1 in writhing test) produced significantly analgesia in hot-plate test and writhing test. Co-administration of verapamil and tramadol prolonged the latency of pain response of mice in hot-plate test.In writhing test, verapamil, nimodipine and nifedipine could potentiate the analgesic effect of tramadol in a dose-dependent manner.Conclusion L-type calcium channel blockers can potentiate tramadol-induced analgesia. Calcium influx mediated by L-type calcium channels may be involved in tramadol-induced analgesia.