Do Hemorheological Properties Influence Vasomotor Reactivity of the Brain Arteries? A Transcranial Doppler Study During Hypo-, Normo- and Hypercapnia

It is still a matter of debate whether hemorheological properties influence vasomotor reactivity of cerebral vessels. Experiments in macroglobulinemic mice by Rosenblum and Asofsky [14] showed that the cerebral arterioles of these animals are less responsive to vasoconstrictor stimuli. Haggendahl and Norback [3] were able to curtail the CO2-induced hyperperfusion of the brain by artificial impairment of blood fluidity in cats. Recently, Muizelaar et al. [9] also demonstrated in animal experiments that blood viscosity changes result in a compensatory adjustment of vessel diameter but that this adjustment does not occur if pressure-dependent autoregulation is defective. However, direct evidence of an interaction between hemorheology and cerebral vasomotion in man is still lacking [15].