[Cerebral circulatory autoregulation in the presence of orthostatic stimuli]

Autoregulation of cerebral blood flow (ACBF) under orthostatic tests (OT) was estimated in acute experiments on rabbits and cats under local anesthesia according to changes of perfusion pressure (PP) in carotid arteries, cerebral blood flow, pressure in the venous system of the brain, and resistance of cerebral vessels. OT was modeled by turning a special table with animal fixed stop of it from horizontal position to head up or down position for 40--80 degrees. In most experiments ACBF correlated with the changes of PP. Different variations of ACBF and its possible mechanisms are discussed.