Effects of GB34 acupuncture on hyperventilation-induced carbon dioxide reactivity and cerebral blood flow velocity in the anterior and middle cerebral arteries of normal subjects

Objectives: To determine whether acupuncture at GB34 affects cerebral blood flow (CBF) via the anterior cerebral arteries (ACAs) and middle cerebral arteries (MCAs). Methods: This study included 10 healthy young male volunteers. CBF velocity and cerebrovascular reactivity (CVR) were measured using transcranial Doppler sonography (TCD). The changes in hyperventilation-induced carbon dioxide (CO₂) reactivity and modified blood flow velocity at 40 mm Hg (CV40) were observed for both ACAs and MCAs before and after GB34 acupuncture treatment. Blood pressure and heart rate were also measured before and after GB34 acupuncture treatment. Results: The CO₂ reactivity of the ipsilateral MCA significantly increased after GB34 acupuncture treatment, compared with that at baseline (P=0.007). In contrast, the CO₂ reactivity of both ACAs and the contralateral MCA remained unchanged. The CV40 of both ACAs and MCAs did not change after GB34 acupuncture treatment and neither did the mean arterial blood pressure and heart rate. Conclusions: GB34 acupuncture treatment increased CO₂ reactivity specifically in the ipsilateral MCA, but had no effect on either the ACAs or the contralateral MCA. These data suggest that GB34 acupuncture treatment improves the vasodilatory potential of the cerebral vasculature to compensate for fluctuations caused by changes in external conditions and could potentially be useful for the treatment of disorders of the ipsilateral MCA circulation.