Abstract
Local metabolites have long been considered to play an important physiological role in regulating regional cerebral blood flow (rCBF). However, the evidence reviewed here emphasizes that the regulation of rCBF by central cholinergic nerves is independent of regional metabolism. Activation of the intra cranial cholinergic fibers originating in the nucleus basalis of Meynert (NBM) and septal complex releases acetylcholine in the cortex and hippocampus, which results in vasodilation and an increase in rCBF in the cortex and hippocampus via activation of both muscarinic and nicotinic acetylcholine receptors. Cutaneous sensory stimulation activates the cholinergic nerves originating from the NBM to enhance rCBF. The increase in rCBF at the defuse cortices during walking appears to include an excitation of this NBM-originating cholinergic vasodilation system. Other various inputs to the NBM may have a similar effects to enhance rCBF via activation of that cholinergic system, provided the stimulation is delivered properly. Thus thecombination of pharmacological and nonpharmacological techniques may provide a balance in our attempts to improve cholinergic replacement therapy.
