Table 4.
Action of KCa1.1 channel inhibitors on Cl− and K+ secretion
| IbTx |
Paxilline |
|||||
|---|---|---|---|---|---|---|
| IbTxΔΔIsc, μA/cm2 | IbTxΔΔIsc/secΔIsc | n | paxΔΔIsc, μA/cm2 | paxΔΔIsc/secΔIsc | n | |
| PGE2 | −45.0 ± 15.3* (0.042) | −0.218 ± 0.058* (0.020) | 5 | +0.4 ± 25.1 (0.99) | +0.055 ± 0.127 (0.69) | 4 |
| CCh/PGE2 | +90.4 ± 25.1* (0.023) | +0.499 ± 0.222 (0.088) | 5 | +98.3 ± 19.0* (0.014) | +0.467 ± 0.206 (0.108) | 4 |
Values are means ± SE (P values). Secretagogue-activated Isc (secΔIsc = secretagogue − control) was measured for PGE2 and CCh/PGE2 (Fig. 4), and inhibitor-induced differences in secΔIsc (inhibΔΔIsc = inhibitor − control) were compared as well as the fractional inhibition (inhibΔΔIsc/secΔIsc). PGE2 (3 μM) was added during steady-state epinephrine activation and CCh (10 μM) was added after PGE2. Inhibitors were added prior to secretagogue activation: paxilline (mucosal and serosal) 1.0 μM; IbTx (mucosal) 300 nM. Significant differences from zero are indicated by asterisks (P values).