ABSTRACT
The effect of changes in vascular transmural pressure upon differential digital plethysmogram (delta DPG) was studied in seven normal subjects. Changes in vascular transmural pressure were produced by the gravitational potential energy change (GPEC method) of an extremity from the heart level. Delta DPG which was characteristic of stability, discrimination and low speed record by modified devices was applied for the experiments including postural, static and dynamic exercises. Room temperature during experiments was kept constant. The Delta DPG-P wave amplitude in maximal elevation of upper and lower extremities (mean±S. D., n) increased to 162.3±33.5% (38) and 176.7±33.4% (12), respectively, and that in maximal lowering of upper and lower extremities decreased to 36.9±10.5% (35) and 37.5±12.6% (15), respectively. These data reveal that the GPEC method may be useful for the determination of arteriolar sensitivity in humans.
