Abstract
The objective of this study was to investigate the possible causal role of renal interstitial hydrostatic pressure (RIHP) in the natriuretic and diuretic resonses of the Wistar rat. The relationship between renal perfusion pressure (RPP), RIHP, and fractional excretion of sodium (FE(Na)) was established in the acutely decapsulated kidney and the contralateral control kidney of the same rat. The renal response to acute saline volume expansion was also studied in control and decapsulated kidney. When RPP was allowed to increase from 100 ± 1.2 to 123 ± 1.3 mmHg in male Wistar rats (n = 10), RIHP and FE(Na) increased significantly from 3.3 ± 0.4 mmHg and 0.57 ± 0.15% to 4.3 ± 0.4 mmHg and 1.77 ± 0.41% in the decapsulated kidney and from 4.1 ± 0.4 mmHg and 0.86 ± 0.17% to 6.9 ± 0.5 mmHg and 2.56 ± 0.38% in control kidney. During saline volume expansion, RIHP and FE(Na) increased significantly from 6.3 ± 0.5 mmHg and 1.30 ± 0.43% to 9.8 ± 0.5 mmHg and 7.53 ± 0.88% in the decapsulated kidney. In the control kidney, RIHP and FE(Na) were 8.3 ± 0.6 mmHg and 1.81 ± 0.35% during control period and increased significantly to 12.7 ± 0.4 mmHg and 9.31 ± 0.50% during acute saline volume expansion. We conclude that the renal capsule is essential for the full increase in RIHP and for the full expression of the natriuretic and diuretic responses of pressure natriuresis and acute volume expansion of Wistar rats.
Original language | British English |
---|---|
Pages (from-to) | 26/1 |
Journal | American Journal of Physiology - Regulatory Integrative and Comparative Physiology |
Volume | 257 |
Issue number | 1 |
State | Published - 1989 |