Mechanisms of blood pressure oscillation caused by central nervous system ischemic response

The experimental results on the hemodynamics and mechanisms of the systemic arterial pressure oscillation (SAPO) produced by the side pressure exertion procedure (SPEP) are presented. The SAPO has revealed us the existence of reciprocal structure at the base of the nervous integration of the cardiovascular system. The reciprocity is found between the type I and type II vasomotor neurons in the bulbar cardiovascular center. The latter is in charge of making the hierarchical set-up in the cardiovascular system, in which blood is supplied to the brain and the cardiac muscle at the expense of blood supply to the other organs. The former is in charge of building antihierarchical set-up, in which blood is provided to the other organs including the cardiac muscle at the sacrifice of blood supply to the brain. During the SAPO, the two groups of the reticular vasomotor neurons alternately discharge, and the two set-ups appear by turns in the cardiovascular system. Thus the animal can survive the SPEP for hours. The SAPO is caused by the coupling of the existing reciprocity with a newly generated central oscillator. The central oscillator has a segmental structure. It is composed of unit oscillators combined in series. This structure works as a ruler of the powerful CNS ischemic response and endows the SAPO with both rigidity and plasticity. It has shown the existence of segmental organization in the CNS in the chronological aspect also and the role of the CNS as that more than mere reflex centers. The study on the SAPO has opened a way to the physiology on emergence of a new order in the animal body.