The Effects Of Chloride Channels Blockers On The Gaba-activated Current In Acutely Dissociated Rat Drg Neurons

Part 1. The effects of chloride channel blockers on GABA-activated current of isolated adult rat dorsal root ganglion neuronsObjective: To investigate the effect of calcium-activated chloride channels (CaCC) blocker niflum -ic acid and volume-regulated chloride channels (VRCC) blocker NPPB on GABA- activated curr ent (IGABA).Methods: The effect of CaCC blocker niflumic acid and VRCH blocker NPPB on GABA-activat- ed current was examined in acutely dissociated neurons of rat dorsal root ganglia by using whole- cell patch clamp methods.Conclusion: It was suggested that CaCC and VRCH may be involved in the IGABA in rat DRG ne- urons. The increase of intracellular Ca²⁺ concentration caused by influx of extracellular Ca²⁺ may be able to activate CaCC and modulate the IGABA .Part 2. The effects of niflumic acid on rat's behavior response in formalin test.Objective: To investigate the analgesic effect of niflumic acid in rat formalin induced inflammato- ry pain .Methods: 24 SD rats were randomly divided into 3 groups, Group NS: normal saline group; Gro- up F: formalin group; Group NFA: Niflumic acid group. Investigate and record the fliching , bitin- gand liching time after 5min, 10 min, 15 min, 20 min, 25 min, 30 min, 35 min, 40 min, 45 min, 50 min, 55 min, 60 min.Results:(1) Compare the F group and the NFA group with the NS group,fliching , biting/liching ti- me obviously increased (P<0.05),except 5min ¹0 min showed no diff-erence (P>0.05), fliching , biting/liching time obviously increased (P<0.05). (2) Compare NFA group with F group, the flich- ing and biting/liching time obviously increased in the first phase (p < 0.05), the fliching and biting /liching time obviously decreased obviously in the second phase 20²5 min,25 ³0 min,30 35 min,35 40 min (P<0.05).Conclusion: According to the experimental results, effects of niflumic acid increase pain in the f- irst phase of formalin test by inhibiting the presynaptic inhibition and release pain in the second p- hase of formalin test by inhibiting the synthesis of PGs.