体循環・腎循環と腎表層容積脈波(RPTG)に関する実験的研究 ： 低酸素負荷による影響と波形成分のフーリエ解析

Abstract

The relation of systemic and renal circulation to renal plethysmogram (RPTG), which reflects the changes in microcirculation of the renal outer cortex, was studied in dogs. The pulse wave of aortic blood pressure (ABP), aortic root blood flow (ABF ; cardiac output), renal blood pressure (RBP), renal blood flow (RBF) and RPTG were simultaneously recorded with ECG during hypoxia induced by respirating gas mixed with 10% O₂ and 90% N₂. The time intervals from the "Q" of ECG to the upstroke point "S", the highest point "P" and the notch "N" of systolic deflection, and the pulse height ratio (Hո/Hр) were measured on the average curve of 5 serial waves. Fourie transport analysis of each wave was done using a microcomputer. During hypoxia, ABF, ABP and heart rate successively increased. RBP increased and RBF decreased, thereby the renal vascular resistance increased. Regarding RPTG, Hո/Hр significantly increased for the first 5 minutes of hypoxia. These results suggest that the vessels in the region near the kidney surface were dilated after the onset of hypoxia. RPTG and the ABF wave were high-frequency, but Fourie analysis showed differences in changes according to the load. The transition of the first component of harmonics in RPTG was similar to the change in total peripheral resistance. These data indicate the possibility of assessing changes in systemic and renal circulation from exermination data of RPTG in both normal and pathological condition.