수입소동맥 저항과 수출소동맥 저항의 상호 작용에 대한 연구 = Interaction between Efferent and Afferent Arteriolar Resistance

다국어 초록 (Multilingual Abstract)

It has generally been accepted that efferent arteriolar constriction increase GFR. However, it has also been shown in mathematical studies that increases in efferent arteriolar resistance beyond some extent causes GFR to decrease. The aim of the present study is to investigate the occurrence of physiological and/or pathophysiological conditions in which GFR is decreased by efferent constriction. The renal hemodynamic data obtained by several investigators were analyzed with a mathematical model of single nephron GFR (SNGFR). The glomerular model is based on a simulation of flow along a glomerular capillary with negligible resistance and uniform ultrafiltration coefficient (K_(f), 0.09 nl · sec^(-1) · mmHg^(-1)).
The data analyzed are from rats which have been shown to achieve filtration pressure equilibrium(FPE) during filtration along the glomerular capillary. The hemodynamic states of rat kidney is characterized by a high K_(f), low RBF, and high vascular resistance. In these animals, inhibition of the renin-angiotensin system was associated with increases in GFR. This was mainly contributed to the increase in K_(f). Analysis with the present model has shown that lowered efferent arteriolar resistance during angiotensin inhibition augmented GFR response to K_(f). The analysis of the data obtained by manipulating efferent resistance during aortic constriction demonstrated the importance of pregiomerular resistance(R_(PRE)) related to efferent resistance (R_(E)). in this hemodynamic condition. The FPE which determines the sensitivity of SNGFR to SNBF and K_(f) is attained nearer the afferent end as R_(PRE) increases further: On the other hand, R_(PRE) had no effect on FPE.
In conclusion, certain physiological manipulation affects R_(PRE) and K_(f) in such fashion that a decrease in R_(E) may have a beneficial effect on GFR and vice versa. This analysis indicates that it is not limited to theoretical importance; it demonstrated that in rat kidneys which have low flow and high afferent resistance the efferent arteriolar dilation can be associated with the promotion of GFR.