ISSN:
1432-2013
Schlagwort(e):
Distal renal tubule
;
Amphiuma
;
Basolateral membrane potential
;
Volume reabsorption
;
Calcium
;
Diuretics
Quelle:
Springer Online Journal Archives 1860-2000
Thema:
Medizin
Notizen:
Abstract In the distal tubule of the isolated kidney of Amphiuma net volume reabsorption (split-oil droplet method) and basolateral membrane potential (Ψ b ) were measured. Luminal perfusion solution could be changed rapidly from 108 mmol·l−1 NaCl plus 0.1 mmol·l−1 calcium to solutions containing 103 or 97 mmol·l−1 NaCl plus 3.6 or plus 7.2 mmol·l−1 calcium. Furthermore, 10−4 mol·l−1 furosemide or chlorothiazide were applied luminally. (1) Addition of 7.2 mmol·l−1 calcium hyperpolarized Ψ b from −73.4 mV to −108.3 mV and inhibited net volume reabsorption. (2) Similarly, when furosemide was injected, Ψ b was hyperpolarized and net volume reabsorption reduced. Application of both high calcium and furosemide further inhibited volume reabsorption. (3) The effects of chlorothiazide were similar to those of furosemide. However, when both high calcium and chlorothiazide were administered Ψ b and volume reabsorption were almost normalized. (4) The data are consistent with the hypothesis that calcium and the diuretics interfere primarly with chloride uptake across the luminal membrane and thus reduce sodium chloride transport. When chlorothiazide in the presence of high luminal calcium almost normalized chloride transport, it is likely that its effects were by stimulating calcium transport and thus increasing intracellular calcium activity.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1007/BF00582101
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