Testing the gate-control theory of pain in man.

According to the gate-control theory of pain, the electrical stimulation of large nerve fibres should stop the pain induced when only C fibres are active. This kind of pain was induced by pressure, repeated pinprick, cold and heat in the ischaemic limb. The peripheral nerves were electrically stimulated in the same way as is done by patients treating their chronic pain by electrical stimulation. There was no change in the quantity nor the quality of the C fibre pain. In other experiments, electrical stimulation of the peripheral nerves induced no change in pain threshold to a heat stimulus when only C fibres were conducting, nor when the whole spectrum of fibres were conducting. Although many experiments have been reported that are consistent with the gate-control theory, the experiments reported here, and others mentioned, are inconsistent with the theory.