ISSN:
1432-1424
Keywords:
parachloromercuribenzoic acid
;
Cl/OH exchange
;
sulfhydryl reagents
;
chloride transport
;
DIDS
;
brush-border membranes
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Chemistry and Pharmacology
Notes:
Summary The effect of the sulfhydryl reagent parachloromercuribenzoic acid (PCMB) on chloride transport was examined in rabbit renal brush-border membrane vesicles (BBMV). PCMB had no effect on the chloride conductive pathway. In the presence of an inside-alkaline pH gradient and a K+/valinomycin voltage clamp, the addition of PCMB stimulated36Cl uptake and induced a threefold overshoot above the equilibrium value, indicating Cl/OH exchange. The effect of PCMB was reversed by dithiothreitol. Cl/OH exchange was not observed in the absence of PCMB. PCMB-activated Cl/OH exchange persisted even when the membrane potential was made inside-negative relative to the controls, thus, demonstrating that PCMB's effect on36Cl uptake under pH-gradient conditions is not mediated by parallel Cl− and H+ conductive pathways. PCMB-activated Cl/OH exchange was inhibited by 4,4′-diisothiocyanostilbene-2,2′-disulfonic acid (DIDS) and 5-nitro-2-(3-phenylpropylamino)-benzoic acid (NPPB) with IC50 values of 290 and 80 μm, respectively. These results demonstrate that modification of sulfhydryl groups by PCMB activates Cl/OH exchange in BBMV.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01871164
Permalink
