| Journal: | Brazilian journal of medical and biological research |
| Database: | PERIÓDICA |
| System number: | 000350346 |
| ISSN: | 0100-879X |
| Authors: | Tararthuch, A.L1 Fernandez, R2 Malnic, G1 |
| Institutions: | 1Universidade de Sao Paulo, Instituto de Ciencias Biomedicas, Sao Paulo. Brasil 2Universidade Federal do Parana, Setor de Ciencias Biologicas, Curitiba, Parana. Brasil |
| Year: | 2007 |
| Season: | May |
| Volumen: | 40 |
| Number: | 5 |
| Pages: | 687-696 |
| Country: | Brasil |
| Language: | Inglés |
| Document type: | Artículo |
| Approach: | Experimental, aplicado |
| English abstract | The interaction between H+ extrusion via H+-ATPase and Cl- conductance was studied in the C11 clone of MDCK cells, akin to the intercalated cells of the collecting duct. Cell pH (pHi) was measured by fluorescence microscopy using the fluorescein-derived probe BCECF-AM. Control recovery rate measured after a 20 mM NH4Cl acid pulse was 0.136 ± 0.008 pH units/min (dpHi/dt) in Na+ Ringer and 0.032 ± 0.003 in the absence of Na+ (0 Na+). With 0 Na+ plus the Cl- channel inhibitor NPPB (10 µM), recovery was reduced to 0.014 ± 0.001 dpHi/dt. 8-Br-cAMP, known to activate CFTR Cl- channels, increased dpHi/dt in 0 Na+ to 0.061 ± 0.009 and also in the presence of 46 nM concanamycin and 50 µM Schering 28080. Since it is thought that the Cl- dependence of H+-ATPase might be due to its electrogenic nature and the establishment of a +PD (potential difference) across the cell membrane, the effect of 10 µM valinomycin at high (100 mM) K+ was tested in our cells. In Na+ Ringer, dpHi/dt was increased, but no effect was detected in 0 Na+ Ringer in the presence of NPPB, indicating that in intact C11 cells the effect of blocking Cl- channels on dpHi/dt was not due to an adverse electrical gradient. The effect of 100 µM ATP was studied in 0 Na+ Ringer solution; this treatment caused a significant inhibition of dpHi/dt, reversed by 50 µM Bapta. We have shown that H+-ATPase present in MDCK C11 cells depends on Cl- ions and their channels, being regulated by cAMP and ATP, but not by the electrical gradient established by electrogenic H+ transport |
| Disciplines: | Medicina |
| Keyword: | Biología celular, pH, ATP, Transporte iónico, Valinomicina |
| Keyword: | Medicine, Cell biology, pH, ATP, Ion transport, Valinomycin |
| Full text: | Texto completo (Ver HTML) |
