[Descending vasoconstrictor fibers in the thoracic region of the spinal cord]

Analysis of the arterial pressure responses to electric stimulation of the spinal cord structures at T1 to L3 showed two zones of the maximal pressure activity in the lateral and medial parts of the lateral funiculus. After destruction of the lateral part at T1-T2 level, a decrease in the systemic arterial pressure occurred after stimulation of the pressor zone of the vasomotor center and structures of the spinal cord at the levels of C5 and ischiatic nerve. These and previously obtained data suggest that the pressor responses to stimulation of the lateral part of the lateral funiculus of the spinal cord are of the reticulospinal origin. Participation of the propriospinal fibers in the pressor responses to stimulation of the medial zone of the lateral funiculus is discussed.