Table 3.
Rates of acid gain following ion substitutions or additions of DIDS or EIPA
| Rate of gain of acid μm s−1 | |||||
|---|---|---|---|---|---|
| Paired comparison of 1st and 2nd intervals for a single cover slip | 1st interval | 2nd interval | n | P | |
| 1 | NaCl−Hepes: NaCl−Hepes | 7.5 ± 1.8 | 8.0 ± 1.4 | 10 | 0.78 |
| 2 | NaCl−HCO3: NaCl−HCO3 | 12.1 ± 1.9 | 15.0 ± 2.3 | 9 | 0.11 |
| 3 | NaCl−Hepes: NMDGCl−Hepes | 7.8 ± 1.1 | 10.1 ± 1.0 | 15 | < 0.02 |
| 4 | NaCl−Hepes: NaCl−Hepes + 5 μm EIPA | 6.8 ± 1.6 | 11.0 ± 1.0 | 10 | < 0.01 |
| 5 | NaCl−HCO3: NMDGCl−HCO3 | 8.1 ± 1.7 | 33.5 ± 3.8 | 27 | < 0.001 |
| 6 | NaCl−HCO3+ 250 μm DIDS: NMDGCl−HCO3+ 250 μm DIDS1 | 9.1 ± 5.7 | 4.2 ± 8.3 | 6 | 0.25 |
| 7 | NaCl−HCO3: early Na-gluconate−HCO3 | 9.7 ± 1.8 | −20.0 ± 5.0 | 14 | < 0.001 |
| 8 | NaCl−HCO3: late Na-gluconate−HCO32 | 9.7 ± 1.8 | 9.5 ± 2.02 | 14 | 0.75 |
| 9 | NMDGCl−HCO3: early NMDG-gluconate−HCO3 | 19.6 ± 2.8 | −9.1 ± 1.5 | 5 | < 0.005 |
| 10 | Na-gluconate−HCO3: NMDG-gluconate−HCO33 | 12.4 ± 0.8 | 29.6 ± 3.8 | 10 | < 0.001 |
1
DIDS was first applied at the start of loading and was then present throughout.
2
The acidwards drift after removal of Cl− was preceded by an alkaline shift in pH of 0.16 ± 0.03 units (see row 7 and Fig. 5). The rate reported is the slope seen after the transient.
3
Gluconate− replaced Cl− during loading with BCECF and throughout the experiment. 4Initial rates of change, i.e. at the onset of the transient alkalinization.