Roles of neurochemicals in central nerve system of mirror image pain in cancer invasion pain model and effects of gabapentin on them / 中国生化药物杂志

ABSTRACT

Objective To study the roles of neurochemicals as Glu, GABA in the spinal cord and SP, DynA1-13 in the cerebral cortex of mirror image pain in cancer invasion pain model and the effects of gabapentin on them.Methods Male BALB/c mices were randomly divided into native group, sham group (injected inactivated S180 sarcoma cell sap), model group (injected 0.2 mL of S180 sarcoma cell sap on the right leg near the greater trochanter of femur) and GBP group (intraperitoneally injected gabapentin 120 mg/kg on the basis of model mice).Mechanical withdraw threshold of the ipsilateral and contralateral hind paw were evaluated by Von Frey hairs before and after surgery.The levels of Glu and GABA in the L3-L5 spinal cord were measured by the high performance liquid chromatography-fluorescence detector ( HPLC-FLD ) and radioimmunoassay was used to detect the concentrations of SP and DynA1-13 in the cerebral cortex.Results The mechanical withdraw threshold of contralateral mirror sites in model mice appeared same trend and approximate degree of decline, following the generation of cancer invasion pain of ipsilateral hind paw.Compared with native group, the concentrations of Glu in the spinal cord and SP in the cerebral cortex in model group were significantly increased (P<0.05, P<0.01), and the levels of GABA in the spinal cord and Dyn A1-13 in the cerebral cortex in model group were significantly decreased (P<0.05, P<0.01).Gabapentin could significantly increase the bilateral mechanical withdraw threshold of model mice and the analgesic effect could maintain to 240 min after administration (P<0.05 or P<0.01).Moreover, gabapentin could reverse the changes of above neurochemicals in the central nervous system of mirror image pain in cancer invasion pain model mice (P<0.01 or P<0.05).Conclusion The mirror image pain phenomenon does exist in the cancer invasion pain model mice induced by S180 sarcoma.The mechanism of mirror image pain occurr and preserve in cancer invasion pain model may involve the changes of Glu, GABA in the spinal cord and SP, Dyn A1-13 in the cerebral cortex, through which gabapentin can relieve mirror image pain in cancer invasion pain model.