RESUMEN
Acupuncture effects are frequently modified by additional acupuncture stimulations. In this study we tried to clarify the mechanisms of such phenomena using the rat jaw opening reflex. The reflex response was elicited by an electrical stimulus of the tooth pulp. The reflex EMG's were recorded from the digastric muscles. Single electroacupuncture stimulation (CS1) was delivered to the skin of a rat.<br>CS1 facilitated the reflex for 20ms after the stimulation, and then inhibited it from 40ms to 250ms. When CS1 was preceded by another electroacupuncture stimulation (CS2), the facilitatory effect induced by CS1 was enhanced CS2-CS1 interval being within 10ms. Then the reflex was inhibited when CS2-CS1 interval was 40-150ms. On the other hand CS1's inhibitory effect was suppressed by CS2 and the reflex reappeared while CS2 preceded CS1 at an interval of 100ms to 1.5s.
RESUMEN
Effects of repetitive electro-acupuncture stimulation on the blink reflex were studied in 23 healthy adults. The blink reflex was elicited by an electrical stimulus of the supraorbital nerve. The reflex EMG's were recorded from the orbicularis oculi muscle. The EMG's were composed of the early component (R1), ipsilaterel to the supraorbital stimulation, with about 10m sec latency and the bilateral late ones (R2) with about 30m sec latency. Electro-acupuncture stimulations consisting of single pulse and a train pulse were given to the skin on “Hogu” point, respectively.<br>Single pulse electro-acupuncture stimulation inhibited the R2 components for 30m sec to 1 sec after the stimulation and its inhibitory effect reached maximum about 100m sec after it. The R2 components were also suppressed when the skin was stimulated by a train of ten pulses with frequency of 2c/s to 20c/s, but the inhibitory effect decreased significantly compared with that of single pulse stimulation. The inhibitory effect was also diminished by 10 to 200 pulses electro-acupuncture stimulation with a frequency of 2c/s.