Role of input from saphenous afferents in altered spinal processing of noxious signal that follows sciatic nerve constriction in rats

An investigation was made into a possible contribution of saphenous nerve to altered central processing of noxious information following sciatic nerve chronic constriction (CCI) in rats. Spinal sciatic neuron spontaneous and noxious evoked activities were recorded in CCI rats, CCI rats with saphenous nerve sectioned just before the sciatic nerve constriction and sham operated rats. The results show (1) high values of spontaneous and noxious evoked activities with prolonged afterdischarges in CCI rats with intact saphenous, (2) comparable high values of spontaneous activity, but significantly reduced noxious evoked activity and afterdischarges in CCI rats with sectioned saphenous, (3) values in the normal range in the sham rats. Potential mechanisms underlying these results are discussed.