Astrocytes function in matching blood flow to metabolic activity.

The brain possesses an intrinsic regulatory mechanism to maintain an adequate supply of O(2) and nutrition despite local increases in neuronal activity. Brain astrocytes function as an intermediary cell type by responding to glutamate released from activated neurons, and they couple cerebral blood flow by producing cytochrome P-450-derived epoxyeicosatrienoic acids that induce vasodilation and increase capillary density.