ISSN:
1432-2013
Keywords:
Vascular smooth muscle
;
Ion flux studies
;
Membrane potential
;
Intracellular pH
;
Diuretics
;
Furosemide
;
DIDS
Source:
Springer Online Journal Archives 1860-2000
Topics:
Medicine
Notes:
Abstract Cl− efflux into various incubation media (PSS) was studied in pieces of rabbit aortae loaded with36Cl. Replacement of HCO 3 − /CO2 by HEPES/O2 in the PSS increased the rate of Cl− efflux by a factor of 2.4. This effect was suppressed in Cl−-free PSS containing isethionate, propionate, or benzenesulfonate, but not in NO 3 − -PSS, or Br−-PSS. The stimulant effect of HCO 3 − withdrawal on Cl− efflux was reduced by 140 μM DIDS, but not by 1 mM furosemide. The Cl− effux was temperature-dependent (Q10=2.3–2.5), and it was not affected on depolarisation by high [K+]0. — The [Cl−]i of rabbit aorta determined by uptake studies with36Cl, decreased slightly (by 15%) below controls in PSS containing 140 μM DIDS, but drastically (from 32.6 to 13.5 mM, i.e. by 59%) in PSS containing 1 mM furosemide. — Withdrawal of HCO 3 − /CO2 depolarized rabbit pulmonary artery in standard PSS and in Br−-PSS or NO 3 − -PSS, but not in benzenesulfonate-PSS. — The pHi of rabbit aorta determined by the distribution of (14C)-DMO, increased in Cl−-free PSS containing isethionate or glucuronate. — It is concluded that transport mechanisms play a major role in the distribution of Cl− in vascular smooth muscle, and that a membrane anion carrier operates in this tissue which can transport Cl− and HCO 3 − across the cell membrane. This mechanism seems to be involved in the regulation of pHi. However, the known high [Cl−]i of vascular smooth muscle is rather mediated by the furosemide-sensitive Na−K−Cl cotransport than by this anion carrier.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00584750
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