| Objective: In this study,we firstly set up the chronic constriction injury of the sciatic nerve model of SD rats as the neuropathic pain model, and then used dorsal root ganglion (DRG) of this model to observe the role of GABA on DRG neurons and explore its mechanisms by using Intracellular recording technique in neuropathic conditions in order to provide with some experimental basis for further discussing the mechanism of neuropathic pain.Methods: 1) CCI model: 30 male SD rats were randomly divided into three groups: control group (n=10), sham-operation group (n=10), and CCI group (n=10), sham and CCI groups were anesthsized under 1 % carbrital (40 mg/kg) and the hot plate test was given to measure paw withdrawal thermal latency (PTWL) at 0 d before operation and at 1 d, 3 d, 5 d, 7 d, 9 d, 11 d and 14 d after operation; 2) In freshly isolated rat DRG samples from control goup, CCI-Ispi group and CCI-contra group, we applied intracellular recording technique,and perfused GABA (10-510-3 mol/L) to observe the role of GABA on DRG neurons in normal and neuropathic conditions.Results: 1) The value of PWTL began to decrease at 1 d after operation, peaked at 7 d after operation and lasted through the whole experiment in neuropathic pain model. (P<0.01); 2) The rest membrane potential were -51±3 mV (n=63),-49±4 mV (n=60) and -50±3 mV (n=58) in control group, CCI Ipsi group and CCI contra group respectively.(P>0.05); 3) The depolarization responses induced by same concentration of GABA were lower in CCI group than in control group. Different concentration induced GABA depolarization responses in both groups showed significant difference. (n≥6, P<0.05)Conclusions: 1) CCI animal model can be considered as an ideal model to explore the mechanism of neuropathic pain; 2) In neuropathic pain, GABA mediated presynaptic inhibition is attenuated which facilitates the nociceptive transmission;... |
PDF Full Text Request