Intracellular Ionic Composition Research Articles

The effect of chlorpromazine on preservation of kidneys with one hour of warm ischaemia.

Abstract Preservation of pig kidneys for 24 hours following one hour of warm ischaemia has been studied in 15 experiments. The material was divided into three groups of five animals. In group A the renal artery was clamped for one hour after heparinization of the animal. The kidney was then removed and preserved for 24 hours by hypothermic storage (0°C), using a short initial cooling perfusion with a perfusate medium which mimics the intracellular ion composition. In group B the experimental conditions were the same as in group A, with the only exception that the animals were treated with i.v. infusion of chlorpromazine (4 mg/kg) before clamping of the renal artery. In group C the kidneys were preserved by continuous hypothermic plasma perfusion, but otherwise treated as in group B. After transplantation the kidney function was followed by means of the creatinine and urea concentration in plasma, and 31 days after transplantation inulin, creatinine, urea and PAH clearances were measured in all the surviving animals. In group A only one animal survived an experimental period of 1 month while four died uraemic 4–7 days after transplantation. In groups B and C all animals survived. The degree of renal functional depression, judged by the concentration of creatinine and urea in plasma, was of the same order of magnitude in groups B and C during the first days after transplantation. A comparison of the renal clearances 31 days after transplantation showed higher values in group B, when the clearances were expressed per 100 g kidney weight.

Sodium-potassium pump and cell volume regulation in frog bladder

In the so-called nonpolarized preparation of frog bladder the mucosal membranes are blocked by liquid paraffin and the intracellular ionic composition is governed solely by the non-mucosal parts of the cell membranes. Results obtained with this preparation support the original idea of a coupled Na +-K + pump operating in ion-transporting epithelial layers and implied in the frog skin model by Ussing and Koefoed-Johnsen. Under the physiological conditions of a normal Na + gradient the operation of the pump leads to a one-to-one exchange of Na + for K + and is inhibited equally by ouabain and by the absence of K + in the adjacent medium. Along with the coupled pump a mechanism regulating the cell volume is present which is insensitive to treatment with ouabain and to K +-free media but is sensitive to inhibition with 2,4-dinitrophenol.

KIDNEY PRESERVATION BY HYPOTHERMIA USING A PERFUSATE MEDIUM WITH “INTRACELLULAR ION COMPOSITION”

Abstract. Preservation of pig kidneys for 24 hours at 0°C has been studied using combined surface and short‐term initial perfusion cooling. As perfusate and storage medium a solution which mimics the intracellular ion composition has been used. Six consecutive experiments were performed. All the animals survived the transplantation and were observed for three months. Measurements of inulin, endogenous creatinine, urea and PAH clearances 10, 31 and 94 days after transplantation showed normal values as compared to a control group of autotransplanted, not long‐term preserved pig kidneys. Apart from a transitory reduction in the renal function during the first days after transplantation, the only permanent reduction found was a reduced maximal tubular excretion of PAH.

A Model for the Long Time-Constant Transient Voltage Response to Current in Epithelial Tissues

Upon passing a step current through the frog gastric mucosa, a transient response in voltage is observed, which can formally be represented by several types of model systems, although some models require elements which are hard to visualize in terms of the known morphology of the mucosa. A physically reasonable model can be constructed by considering the changes in intracellular ionic composition which arise due to current flow, and the consequent changes in diffusion potentials across the two cell membranes. A simple model has been developed which fits the observed long time-constant portion of the transient at low current densities, and predicts departures from exponential behavior at larger currents. Since reasonable values for membrane resistance and cell volume give a fit, it is proposed that this model may account for the long time-constant portion of the transient response. There is no reason to expect that similar considerations do not hold for epithelial tissues in general.

Transcellular transport of isosmotic volumes by the rabbit gall-bladder in vitro.

1. Fluid transport rate and oxygen consumption (Q(O2)) were studied in rabbit gall-bladder preparations in vitro exposed on both sides to identical Ringer solutions with NaCl concentrations (and osmolarities) varying from 70 to 140 m-equiv Na(+)/l.).2. The time sequence of acute effects on transport rate resulting from sudden changes in the NaCl concentration of the bathing solutions indicated that, (a) as a primary effect, fluid volume transfer rate remained unaffected whereas Na transport rate changed abruptly in direct proportion to the Na concentration of the bathing media; (b) a secondary, delayed and partly reversible depression of fluid transfer rate following elevation of the NaCl concentration was observed only when the rate of transport was relatively high initially.3. A fixed, and highly significant, linear relationship between changes in transport-linked oxygen consumption (DeltaQ(O2)) and measured net fluid volume transport (DeltaT(vol)) was found independent of the NaCl concentration of the bathing media, dQ(O2)/dT(vol) being 0.22 +/- 11% and 0.25 +/- 8% in bladders incubated in solutions containing 140 and 70 m-equiv Na(+)/l. respectively.4. Oxygen consumption per equiv of Na(+) (calculated) transported varied in inverse proportion to the Na concentration of the bathing media, dQ(O2)/dT(Na) being 0.0016 +/- 11% and 0.0036 +/- 8% in ;140 R' and ;70 R' solutions, respectively.5. Removal of K from the bathing solutions was followed by a gradual and partly reversible depression of fluid transport rate to a minimum level (about 100 x 10(-4) mul H(2)O. min(-1).mg(-1)) independent of the initial transport rate.6. It is concluded that the range of absorption rates of isosmotic fluid from the gall-bladder lumen represents a range of energy requiring capacities for transfer of fluid volume units; the data suggest that the intracellular (cytoplasmic) ion composition, depending on the presence of external K, as well as hormonal action may influence the capacity of the transcellular fluid transport mechanism.7. A model (a ;mechanical volume pump') for transcellular transfer of fluid volume units, allowing for flexible specificity with regard to the actively transported solutes, and requiring the presence of Na(+) and Cl(-), is proposed.

The polarographic determination of the respiration of the small intestine of rat

1. 1. Methods are described for the polarographic determination of the oxygen consumption of various preparations of rat small intestine. 2. 2. In the presence of glucose the rate of respiration of sacs of everted jejunum is less than the rate for rings cut from the whole wall of the jejunum. When either pyruvate, glucose, galactose or 3- O-methylglucose is added to the medium, the rate of respiration of rings of the upper jejunal wall is increased above the level found with no substrate present. 3. 3. In the presence of either pyruvate, glucose, galactose or 3- O-methylglucose, the respiration rate of strips of jejunal mucosa in media which contain Na is reduced below the high level found with no exogenous substrate. 4. 4. In the absence of exogenous substrate, the respiration of strips of jejunal mucosa is reduced when either choline, lithium or potassium chloride is substituted for the NaCl in the incubation medium. 5. 5. It is concluded that in the presence of glucose, the respiration rate of the mucosal cells is highest in the case of strips of isolated mucosa, has an intermediate value for the mucosa of rings of the whole wall and has the lowest value in the case of the mucosa of the whole everted sacs. It is suggested that the findings are explicable if the rate of respiration of the mucosal cells is determined in part by the intracellular ionic composition.