The dogs and rabbits, electrical stimulation of the vertebral nerve reduced the pressure in the carotid and the vertebral--basillar arterial systems leaving the general arterial pressure unaltered. Simultaneously the values of pH, PO2 PCO2, and buffer bases decreased in the blood flowing from the dog brain. The data obtained suggest that stimulation of the vertebral nerve reduces the blood flow in the vertebral artery which, in conditions of occlusion of the contralateral vertebral artery, leads to the circulatory regional hypoxia of the brain.