Electric-acupuncture increases blood flow to the ovaries The purpose of the present study was to investigate changes in ovarian blood flow in response to electric acupuncture stimulation at different frequencies and intensities in anaesthetized rats. Whether the ovarian sympathetic nerves were involved in ovarian blood flow responses was elucidated by severance of the ovarian sympathetic nerves. In addition, how changes in the systemic circulation affected ovarian blood flow was evaluated by continuously recording blood pressure. ovarian blood flow was measured on the surface of the left ovary using laser Doppler flowmeter. Acupuncture needles with a diameter of 0.3 mm were inserted bilaterally into the abdominal and the hindlimb muscles and connected to an electrical stimulator. Two frequencies—2 Hz (low) and 80 Hz (high)— with three different intensities—1.5, 3, and 6 mA—were applied for 35 s. Both low- and high-frequency electric acupuncture at 1.5 mA and high-frequency electric acupuncture at 3 mA had no effect on ovarian blood flow or mean arterial blood pressure (MAP). Low-frequency electric acupuncture at 3 and 6 mA elicited significant increases in ovarian blood flow. In contrast, high-frequency electric acupuncture with an intensity of 6 mA evoked significant decreases in ovarian blood flow, followed by decreases in MAP. After severance of the ovarian sympathetic nerves, the increases in the ovarian blood flow responses to low-frequency electric acupuncture at 3 and 6 mA were totally abolished, and the responses at 6 mA showed a tendency to decrease, probably because of concomitant decreases in MAP. The decreased OBF and MAP responses to high-frequency electric acupuncture at 6 mA remained after the ovarian sympathectomy, and the difference in the responses before and after ovarian sympathectomy was nonsignificant. In conclusion, the present study showed that low-frequency electric acupuncture stimulation increases ovarian blood flow as a reflex response via the ovarian sympathetic nerves, whereas high-frequency electric acupuncture stimulation decreases ovarian blood flow as a passive response following systemic circulatory changes. Reference Stener-Victori et al. (2003) Ovarian blood flow responses to electro-acupuncture stimulation at different frequencies and intensities in anaesthetized rats. Autonomic Neuroscience: Basic and Clinical 108, 50– 56.