[Systemic vascular reactions to a decrease in volumetric blood flow velocity during artificial circulation]

In anesthetized cats with artificial circulation, a decrease in the systemic perfusion pressure (SPP) following reduction of the blood flow volume velocity evokes under conditions of weakly pulsating blood flow a constrictory response of neurogenic character which can be compensated for by an opposite myogenic response in conditions of pulsating blood flow. These differences only occur at a high enough initial level of the SPP. The myogenic component of regulation of the resistance vessels tonus seems to be suppressed in conditions of weakly pulsating blood flow. Questions bearing on regulation of the systemic hemodynamics, are discussed.