Table 1.
Comparative analysis of transport responses of endogenous NHE1 and transfected NHE3 to 10−4 M HOE
| 10−4m HOE 694% inhibition of NHE activity | |||
|---|---|---|---|
| Cell line | NHE3 construct | NHE3 | NHE1 |
| A6-NHE3 | Wild type | 48.7 ± 4.3*† (4) | 89.8 ± 4.6* (3) |
| A6-NHE36ser | S513G, S552A, S575A, S661A, S690G, S804G | 56.2 ± 2.2*† (4) | 84.4 ± 7.7* (4) |
| A6-NHE3S513G | S513G | 56.6 ± 4.6*† (4) | 84.8 ± 2.0* (3) |
| A6-NHE3S552A | S552A | 54.8 ± 11.0*†(4) | 87.2 ± 7.0* (4) |
| A6-NHE3S575A | S575A | 64.3 ± 2.7† (4) | 87.8 ± 2.8* (4) |
| A6-NHE3S605G | S605G | 59.2 ± 5.4*† (5) | 88.3 ± 1.2* (3) |
| A6-NHE3S634A | S634A | 62.3 ± 6.4*† (4) | 84.9 ± 0.8* (4) |
| A6-NHE3S661A | S661A | 55.9 ± 4.7† (3) | 85.9 ± 1.4* (3) |
| A6-NHE3S690G | S690G | 53.7 ± 3.5† (6) | 86.2 ± 3.4* (4) |
| A6-NHE3S804G | S804G | 62.0 ± 1.8*† (4) | 85.5 ± 1.6* (5) |
The effect of HOE 694 on NHE activity was assessed by comparison of the rate of pHi recovery from an NH4Cl-induced acid load in the absence or presence of the inhibitor. Data represent the means ± s.e.m. of inhibition of pHi recovery rates following a 2 min exposure of apical NHE3 or basolateral NHE1 to 10−4m HOE 694. The number of experiments performed under identical experimental conditions is given in parentheses.
*
Significant vs. control
†
significant vs. basolateral effect of HOE 694.