Cai Dawei, Yang Zhiliang*, Wu Ruiliang (The Department of Acupuncture Anesthesia Investigation, Shanghai First People's Hospital)
*The Department of Education, Shanghai Normal University.
Pain consists of two components: sensation and emotion. The analgesic effect of needling has been verified by a great number of animal experiments as well as many observations on human bodies. Does the needling exert its influence on the pain sensation or on the emotion component or on both? Our experiments were done on normal human bodies to observe the influence of the electric needling stimulation on the pain sensation and the emotion components. Observations were made with the same nerve electric needling and electric needling of the traditional acupuncture points respectively, which are the two commonly used methods in clinical practice.
Effect of the Same Nerve Electric Needling Stimulation.
The same nerve electric needling implies that the nerve impulses induced by the electric needling and traumatic stimulation all conducted along the same nerve to the central nervous system. The experiments were carried out in normal human bodies, and observations were made on the correlation between the intensity of stimulation and the type of nerve fibres excited, between pain sensation and emotion, and also on the influence of the same nerve electric needling on A ë wave of the compound action potential produced by pain stimulus, the pain sensation and the emotion components.
Experiments were proceeded in 12 human subjects. Using 0.3 ms single square wave, the distal end of the sural nerve was stimulated conitnuously once per second for 100 seconds. With gradual increase of the intensity of stimulation until the subject would have feelings of touch, slight numbness, marked numbness, slight pain (i.e. pain threshold), moderate pain (between the slight and severe pain), severe pain (pain unwillingly borne, generally referred to as unbearable pain threshold) and exceedingly severe pain, altogether seven degrees of sensation. In the same time, the emotional changes of the subjects during different feelings, the electrical response of the sural nerve were recorded. Using the stimulus intensities producing slight, moderate and severe degrees of pain and corresponding emotional changes and electrical responses as control, stimulation of the middle-portion of the sural nerve proximal to the pain stimulus was made by electric needling with a frequency of 200 Hz, and the intensity of current was gradually increased not causing marked pain and receptable to the subjects throughout the 30 minutes' stimulation. The effect of electric needling on the sensation of pain, the emotional reaction to pain and the electrical response of the sural nerve was observed during the electric needling and 30 minutes after it.
The excitation of A á- fibres induced a sensation of touch or numbness without marked change of emotion while the stimulation of A á--ë fibres induced pain sensation. A stronger stimulation heightened the pain sensation from bearable to unbearable degree with marked emotional changes.
Various intensities of electric needling produced different inhibitory effects on the emotion, the pain sensation and the Aë wave of the action potential induced by slight, moderate and strong pain stimuli. The inhiibtory effect of electric needling exciting Aë wave was distinctly greater than that of non-exciting Aë wave. With the same intensity of electric needling, the inhibitory effect was most marked on the emotional reaction toward pain, less so on the action potential and least on pain sensation. The experimental results suggest that side from blocking, to some extent, the conduction of peripheral pain impulses the same nerve electric needling could distinctly improve the emotional reaction to pain, and change the original unbearable sensation in response to the severe pain stimulus into a bearable one. Hence, in investigating the mechanism of the same nerve electric needling, it is deemed to be necessary to consider both effects of needling, the effect on the pain sensation and that on the pain emotion.
A slow increase of the intensity of high frequency continuous stimulation may excite A ë fibres but not cause pain sensation. It is possible to make use of this "adaptation" phenomenon to improve the analgesic effect of electric needling.
*The Department of Education, Shanghai Normal University.
Pain consists of two components: sensation and emotion. The analgesic effect of needling has been verified by a great number of animal experiments as well as many observations on human bodies. Does the needling exert its influence on the pain sensation or on the emotion component or on both? Our experiments were done on normal human bodies to observe the influence of the electric needling stimulation on the pain sensation and the emotion components. Observations were made with the same nerve electric needling and electric needling of the traditional acupuncture points respectively, which are the two commonly used methods in clinical practice.
Effect of the Same Nerve Electric Needling Stimulation.
The same nerve electric needling implies that the nerve impulses induced by the electric needling and traumatic stimulation all conducted along the same nerve to the central nervous system. The experiments were carried out in normal human bodies, and observations were made on the correlation between the intensity of stimulation and the type of nerve fibres excited, between pain sensation and emotion, and also on the influence of the same nerve electric needling on A ë wave of the compound action potential produced by pain stimulus, the pain sensation and the emotion components.
Experiments were proceeded in 12 human subjects. Using 0.3 ms single square wave, the distal end of the sural nerve was stimulated conitnuously once per second for 100 seconds. With gradual increase of the intensity of stimulation until the subject would have feelings of touch, slight numbness, marked numbness, slight pain (i.e. pain threshold), moderate pain (between the slight and severe pain), severe pain (pain unwillingly borne, generally referred to as unbearable pain threshold) and exceedingly severe pain, altogether seven degrees of sensation. In the same time, the emotional changes of the subjects during different feelings, the electrical response of the sural nerve were recorded. Using the stimulus intensities producing slight, moderate and severe degrees of pain and corresponding emotional changes and electrical responses as control, stimulation of the middle-portion of the sural nerve proximal to the pain stimulus was made by electric needling with a frequency of 200 Hz, and the intensity of current was gradually increased not causing marked pain and receptable to the subjects throughout the 30 minutes' stimulation. The effect of electric needling on the sensation of pain, the emotional reaction to pain and the electrical response of the sural nerve was observed during the electric needling and 30 minutes after it.
The excitation of A á- fibres induced a sensation of touch or numbness without marked change of emotion while the stimulation of A á--ë fibres induced pain sensation. A stronger stimulation heightened the pain sensation from bearable to unbearable degree with marked emotional changes.
Various intensities of electric needling produced different inhibitory effects on the emotion, the pain sensation and the Aë wave of the action potential induced by slight, moderate and strong pain stimuli. The inhiibtory effect of electric needling exciting Aë wave was distinctly greater than that of non-exciting Aë wave. With the same intensity of electric needling, the inhibitory effect was most marked on the emotional reaction toward pain, less so on the action potential and least on pain sensation. The experimental results suggest that side from blocking, to some extent, the conduction of peripheral pain impulses the same nerve electric needling could distinctly improve the emotional reaction to pain, and change the original unbearable sensation in response to the severe pain stimulus into a bearable one. Hence, in investigating the mechanism of the same nerve electric needling, it is deemed to be necessary to consider both effects of needling, the effect on the pain sensation and that on the pain emotion.
A slow increase of the intensity of high frequency continuous stimulation may excite A ë fibres but not cause pain sensation. It is possible to make use of this "adaptation" phenomenon to improve the analgesic effect of electric needling.
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