Cholinergic vasodilative system in the cerebral cortex: effects of acupuncture and aging

This article presents a review of our studies on the cholinergic vasodilative system in the cerebral cortex in relation to the effects of acupuncture and aging. In anesthetized rats, manual acupuncture-like stimulation of the cheek, forepaw, upper arm, and hindpaw increases the cortical cerebral blood flow (CBF). The mechanism for the increased response of CBF due to forepaw stimulation has been found to be a reflex response whose afferents are Groups III and IV somatic afferent fibers and whose efferents are cholinergic fibers that originate in the nucleus basalis of Meynert. Although the cholinergic cortical vasodilation to nucleus basalis of Meynert stimulation at high intensities declines with age, the increased response of CBF induced by natural somatic afferent stimulation, such as an acupuncture-like stimulation of a forepaw, is well maintained even in very old rats (approximately 3 years of age). These findings in anesthetized rats may support the application of acupuncture to elderly people and patients with disturbances in the CBF by activating the intracranial cholinergic vasodilative system.