The Japanese journal of physiology
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The effect of acupuncture-like stimulation of various areas (cheek, forepaw, upper arm, chest, back, lower leg, hindpaw, perineum) on cortical cerebral blood flow (CBF) was examined in anesthetized rats. An acupuncture needle (diameter, 340 microm) was inserted into the skin and underlying muscles at a depth of about 5 mm and twisted to the right and left once a second for 1 min. CBF of the cortex was measured using a laser Doppler flowmeter. ⋯ The increase in CBF induced by forepaw stimulation was almost abolished by intravenous administration of muscarinic and nicotinic cholinergic blocking agents (atropine 5 mg/kg and mecamylamine 20 mg/kg), and by bilateral lesions in the nucleus basalis of Meynert. Acupuncture-like stimulation of a forepaw increased acetylcholine release in the cerebral cortex. We concluded that the increase in CBF, independent of systemic blood pressure, elicited by acupuncture stimulation is a reflex response in which the afferent nerve pathway is composed of somatic group III and IV afferent nerves, and efferent nerve pathway includes intrinsic cholinergic vasodilators originating in the nucleus basalis of Meynert.