On the application of the occlusion time method for measurements of lateral net fluxes in the proximal convolution of the rat kidney

A study of proximal tubular compliances in normotensive and spontaneously hypertensive rats, and the effect of anaesthesia on the compliance

Proximal tubular compliance (C) was measured in free flow microperfusion experiments from the initial slope of the increase in proximal luminal pressure divided by the step input of volume flow delivered from a microperfusion pipette inserted in a downstream proximal convolution. Five groups of rats were studied: Munich Wistar (WU, n = 11) and Sprague-Dawley rats (SPRD, n = 6) anaesthetized with inactin; and SPRD (n = 11), Wistar Kyoto (WKY, n = 9), and spontaneously hypertensive rats (SHR, n = 11) anaesthetized with halothane. In the inactin groups, C was: 0.309 +/- 0.161 and 0.266 +/- 0.136 nl mm Hg-1, respectively. In the halothane groups, C was: 0.125 +/- 0.023, 0.125 +/- 0.029, and 0.119 +/- 0.0127 nl mm Hg-1, respectively. The means in the inactin groups were significantly higher than those from the halothane groups (P less than 0.001). It is concluded that the choice of anaesthetics has a profound influence on the proximal tubular compliance in the rat, and that the compliance of SHR is equal to that of normotensive rats.

Effects of halothane-nitrous oxide inhalation anesthesia and Inactin on overall renal and tubular function in Sprague-Dawley and Wistar rats

Real function, plasma renin concentration (PRC) and prostaglandin (PG) excretion rate was studied in groups of Sprague-Dawley (SPRD) and Wistar (WIST) rats anesthetized with either Halothane-N2O or Inactin. Conscious rats were used as controls. A. In Halothane-N2O anesthesia inulin clearance (CIN) and absolute proximal reabsorption rate (APR) was moderately decreased (by about 20%), while renal plasma flow (RPF), urine flow and solute excretion remained unchanged as compared to conscious rats. There was a linear relationship between the reciprocal of the proximal occlusion time (OT) and CIN in Halothane anesthesia indicating that the proximal luminal diameter was constant and independent of CIN. B. Inactin anesthesia CIN was similarly reduced but APR was more depressed (by about 35%). RPF and solute excretion rate decreased only in SPRD rats, while urine flow was significantly reduced in both strains. 1/OT was invariant to changes in CIN indicating luminal diameter variations in proportion to CIN. Urinary PGE2-and PGF2 alpha excretion rates and PRC were moderately elevated in operated animals of both strains regardless of the anesthetics used. It is concluded that renal functional parameters in surgically prepared rats are more severely depressed by Inactin than by Halothane-N2O anesthesia. The gas anesthesia is equally well tolerated by both strains of rats.

Effects of dextran 40 on urine flow and composition during renal hypoperfusion in dogs with osmotic nephrosis

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