Focal Cortical Blood Flow Activation Is Regulated by Intrinsic Cortical Cholinergic Neurons

We evaluated the cholinergic mechanism underlying focal cortical vascular response to neuronal activation, using positron emission tomography for use on animals to measure cerebral blood flow and glucose metabolism activation upon vibrotactile stimulation in cats. Bromopyruvate, which blocks acetylcholine synthesis through inhibition of the production of acetyl CoA, was injected into the cerebral cortex and basal forebrain as well as the sphenopalatine ganglion, all of which have been confirmed to supply cholinergic terminals to the cerebral cortex. Although glucose metabolism was preserved, indicating that the neuronal activities were enhanced, cerebral blood flow increase during cortical neuronal activation was abolished by bromopyruvate injection into only the cerebral cortex and not other cholinergic systems. We conclude that the cholinergic intrinsic neurons control the focal cerebral blood flow increase in response to neuronal activation.