[Functioning of the microvascular mechanisms in the pial artery system]

In rabbits, the functional behavior of the pial arterial offshoots (PAO), the pial arterial anastomoses (PAA), and the precortical arteries (PCA), was studied. In functional and postischemic hyperemia, as well as on changes of cerebral blood flow (caused by changes of the systemic arterial pressure), dilatatory and constrictory responses of the active portions of the microvessels suggest that the PAO and PAA participate mainly in the regulation of blood supply to the cerebral cortex adequate to its metabolic demands, while the PCA get involved during superfluous inflow of blood to the cerebral cortex.