Acupuncture and sensory thresholds.

The effect of acupuncture on sensory thresholds was studied in 6 healthy subjects. The modes of acupuncture studied were: 1. manual stimulation, 2. electrical stimulation at 2 Hz, 3. electrical stimulation at 80 Hz. Superfiscial-acupuncture was used as placebo. Insertions of needles or application of electrodes were bilateral, at St 7 (intrasegmental) or Li 4 (extrasegmental). The study showed that manual or electro-acupuncture were effective when used intrasegmentally, raising pain threshold values 1.1 to 1.4 times that prior to stimulation. The pain threshold elevation obtained was not significantly related to plasma levels of beta-endorphin, ACTH or prolactin. Other sensory thresholds, thermal, vibrotactile and electrotactile were unaffected by such conditioned stimulation. Superfiscial-acupuncture had no significant effect on the sensory thresholds tested.