Effect of acupuncture on the blood flow of the rat fore- and hind-limb skin

The change in blood flow of the fingers and foot pads induced by acupuncture needle insertion (acupuncture) or by electrical stimulation delivered through the needles (electro-acupuncture) to acupuncture points (Hegu, Waiguan, or Housanli) was bilaterally measured with a laser blood flow meter in rats anesthetized with pentobarbital sodium. Acupuncture and electro-acupuncture of the Hegu significantly increased mean blood flow of the ipsilateral finger pad to 221% and 190% (mean blood flow before needle insertion, 100%) 5 min after stimulation, and 172% and 175% 15 min after stimulation, respectively. Electroacupuncture of the Hegu bilaterally decreased blood flow of foot pads 15 min after removal of the stimulating needle. Acupuncture and electro-acupuncture stimuli applied to the Waiguan increased blood flow of the ipsilateral fingerto 155% and 166% 5 min afterstimulation and 154% and 156% 15 min after stimulation, respectively. Acupuncture and electro-acupuncture stimulation of the Housanli decreased blood flow in the ipsilateral food pad to 84% and 90% 5 min after stimulation, 89% and 91% 15 min after stimulation, and 91% and 90% 15 min after needle removal, respectively. Both treatments also decreased blood flow of the contralateral foot pads and bilateral finger pads 5 min after stimulation. These results show that acupuncture and electro-acupuncture of the Hegu and Waiguan increased blood flow of the ipsilateral fingers, while acupuncture and electro-acupuncture of the Housanli induced a sustained decrease in blood flow of the ipsilateral foot pad during stimulation and a transient decrease in blood flow of the contralateral foot pad and of the ipsilateral and contralateral fingers