Studies on the relationship between rat renal medullary cell volume and external anion concentration in hyperosmolal media.

Abstract

SUMMARY1. The volumes of cells in slices of rat renal outer medulla have been examined following incubation for 25 min in hyperosmolal media (650 and 950 m-osmole/kg H20) containing independently variable concentrations of Cl (70-235 mM) and HCO3(10-60 mM) (gas phase 95 % 02/5 % C02). 2. For any given level of external Cl concentration cell volumes were reduced by increasing the external HCO3 concentration. These reductions were accompanied by net loss of cellular K and Cl. In confirmation of earlier findings, cell volumes were also reduced by increasing external Cl concentration.3. Experiments in which the HCO3 concentration and pH of the incubation media were independently varied by the use of N-2-hydroxyethylpiperazine-N'-2-ethanesulphonic acid (HEPES)/100% 02 showed that it is the HCO3 anion per se which influences cell volume.4. The anion exchange inhibitor 4-acetamido-4'-isothiocyanatostilbene-2,2'-disulphonic acid (SITS, disodium salt, 1 mM) abolished the dependence of cell volume upon HCO3 but not upon Cl.5. Acetazolamide (1 mM) influenced (reduced) cell volumes only in the presence of low (10 mM) HCO3.6. CNS (25 mm) also markedly reduced cell volumes in media containing 10 mM-HCO3 and, to a lesser extent, 25 mM-HCO3. It was without effect on cell volume when external HCO3 was 60 mM.7. The presence of CNS was associated with the significant cellular net accumulation of Cl in media in which either Cl or HCO3 concentration (or both) was low (70 or 130 mm and 10 mm respectively).8. The outer medullary [35S]CNS space at 25 min, determined for slices incubated in a representative selection of the various media employed in this study, exceeded the [14C]inulin space by 1-77 ,1./10 mg wet weight.

Cellular swelling in slices of rat renal outer medulla incubated in the presence of bovine serum albumin.

“…The latter finding agrees with Rorive, Nielsen & Kleinzeller (1972) Law, 1979), nor does the inset in the present Fig. 1 In a previous report from this laboratory it was stated that pH did not significantly effect cell volume in the presence of constant concentration of HCO0- (Law, 1980 (Longsworth & Jacobsen, 1949). Thus b.s.a.…”

“…Additions were made using the solids or dropwise using molar aqueous solutions. As noted previously (Law, 1980), the pH of media containing HCO-slowly increases with time in the presence of buffers based on sulphonic acid. Preliminary investigations were carried out in order to estimate the likely alteration in pH occurring over 100 min, and buffers were added to media as shortly as possible before the start of experimental incubations.…”

“…This was estimated using a Cl-sensitive electrode (EIL Chloride Electrode Model 8004-2) coupled to a Corning-EEL 109 pH/mV meter as previously described (Law, 1980 (Law, 1975b), and this time was selected not because the volume of distribution has any unique significance but because it affords a useful comparison between the sucrose space in the presence and absence of b.s.a.…”

“…(2) Chloride. This was estimated using a Cl-sensitive electrode (EIL Chloride Electrode Model 8004-2) coupled to a Corning-EEL 109 pH/mV meter as previously described (Law, 1980). Volumes of distribution of sucrose and b.s.a.…”

Characteristics of ionic binding by rat renal tissue in vitro.

“…In one series of experiments slices were incubated for 6 h at 37 0C in medium containing Na acetate (60 mmol/l), bovine serum albumin Fraction V (BDH Biochemicals; 5 g/l) and chondroitinase ABC (Sigma Chemical Company; 0-2 u./ml), adjusted to pH 8-0 with Tris (Yamagata, Saito, Habuchi & Suzuki, 1968) solubility product of AgSCN. In order to overcome this an interpolative method, using a series model NaCl/NaSCN solution, was used as previously described (Law, 1980). P043-also interferes with Cl-estimations.…”