Velocity pulse advances pressure pulse by close to 45° in the rat pial arterioles

摘要: In order to clarify the phase relationship between velocity pulse and pressure propagating along microvessels, red cell intravascular were simultaneously measured in rat pial arterioles of 41-53 microm diameter with a high temporal resolution by laser-Doppler anemometer servo-null micropressure system. It was found that preceded all 18.7-35.6 ms. The corresponding difference 43.6+/-6.9 degrees (mean +/- SD), which is not statistically different from 45 degrees. value consistent predicted for blood flow microvessels small reflection coefficient at frequencies as low heart rate rats. present results suggest upstream changes are transmitted faster than microvasculature.