SIEGER, U and BRAHM, J and BAUMANN, R (1994) CHLORIDE AND BICARBONATE TRANSPORT IN CHICK EMBRYONIC RED-BLOOD-CELLS. JOURNAL OF PHYSIOLOGY-LONDON, 477 (3). pp. 393-401. ISSN 0022-3751, 1469-7793
Full text not available from this repository.Abstract
Unidirectional efflux of Cl-36(-) and (HCO3-)-C-14 from erythrocytes of 4- to 16-day-old chick embryos was measured under steady-state conditions at 37 degrees C and pH 7.7. The efflux rates were high, > 3 s(-1), and were, therefore, measured by means of the continuous flow tube method. 2. At day 4 of development the range of permeability coefficients for bicarbonate and chloride (P-HCO3 and P-Cl was 1-30 x 10(-4) cm s(-1), with average values of respectively 10 x 10(-4) and 8 x 10(-4) cm S-1. However, the results can be divided into two groups, one with P-HCO3 and P-Cl above 12 x 10(-4) cm s(-1), and one with values below 5 x 10(-4) cm s(-1). The same range of values was also obtained for day 6 erythrocytes, but the overlap is more conspicuous. At day 16, P-HCO3 and P-Cl were respectively 9 x 10(-4) and 8 x 10(-4) cm s(-1) (37 degrees C, pH 7.7j. In adult chicken red blood cells P-HCO3 and P-Cl were respectively 7 x 10(-4) and 4 x 10(-4) cm s(-1), and in human red blood cells the respective values were 5 6 x 10(-4) and 4 x 10(-4) cm s(-1) 3. Chloride self-exchange, measured at 0 degrees C, was almost completely inhibited by addition of 1mM 4,4 '-diisothiocyanostilbene-2,2'-disulphonate (DIDS) at both days B and 16 of embryonic development, supporting the finding that the embryonic chick erythrocytes also have a transmembrane anion exchanger similar to that of other red cells. 4. The intracellular pH (pH(i)) was measured at constant extracellular pH (pH(i)) using the pH-dependent fluorescent dye SNARF AM-1. The difference between pH(o) and pH(i) decreased from 0.600 units at day 4 to 0.245 units at day 16 of development. 5. The results suggest that a functionally active band 3 protein, AE1, is present in the membrane at very early stages of embryonic development and is capable of transporting monovalent anions. However, at the early stages the anion transporter appears not to be able to regulate intracellular pH as efficiently as in mature cells. During embryonic development the ability of AE1 to regulate pH(i), improves.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | ERYTHROCYTES; KINETICS; WATER; |
| Depositing User: | Dr. Gernot Deinzer |
| Last Modified: | 19 Oct 2022 08:40 |
| URI: | https://pred.uni-regensburg.de/id/eprint/53237 |
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