Abstract:Under anesthesa and sterilised surgery, a pe of Stainless Steel filament(4mm in length and 0. 5-0. 8mm in diameter)was inserted into the L5 intervertebral foramen in the rat,thus producing a chronic and steady compression on the dorsal root poghon(DRG)and its nerve roots. Test of foot withdeawal latency caused by rthe heat showed that the hind pow of the injured side registered a sboificant reduction in foot withdrawal latency and manifested a persistent hyperalgesia 5 to 42 days after surgery. Spotuneous boarge of A-type fiber from neurons in the injured DRG Ptesental a markedly increased incmence and various rhythm petterns. Thde neurons in the injured DRG had a gredy enhanced sensitivity to mechanital compression stimulation and a obviously prolollged after discharge. Relatively specific excitutory responses occurred when the injured DRG was immernd in m soution. Application of this experimentul model may promote further research and understandings of the neural mechanisms by which chronic compression of DRG induces low hack pein and sciatica.
