Table 4.
Effects of low and high luminal calcium concentration, calcium chelator, Ca-ATPase inhibitor, and IP3 receptor antagonist on flow-induced changes in chloride absorption under low and high perfusion rates in mouse proximal tubules
| 5 nl/min |
20 nl/min |
||||||
|---|---|---|---|---|---|---|---|
| Group | n | JCla, pmol·min−1·mm−1 | n | JClb, pmol·min−1·mm−1 | ΔJCl (JClb − JCla) | ΔJCl/JCla*100 | (ΔJCl/JCla)/(Δ T/Tr) |
| Control (1.2 mM CaCl2) | 15 | 56.3 ± 5.2 | 15 | 63.8 ± 6.0 | 7.45 ± 7.9 | 13.2 ± 10.7 | 0.30 ± 0.24 |
| 5 mM CaCl2 | 6 | 37.2 ± 10.1NS | 6 | 40.8 ± 10.9nsNS | 3.60 ± 14.8NS | 9.7 ± 29.3NS | 0.15 ± 0.44NS |
| 0 mM CaCl2+ EGTA | 6 | 56.4 ± 7.9NS | 6 | 64.1 ± 11.5nsNS | 7.74 ± 14.0NS | 13.7 ± 20.4NS | 0.37 ± 0.55NS |
| BAPTA+0 mM CaCl2 +EGTA | 6 | 63.7 ± 14.1NS | 6 | 20.8 ± 4.4*††† | −42.86 ± 14.8†† | −67.3 ± 6.9††† | −1.68 ± 0.17††† |
| Thapsigargin | 6 | 24.0 ± 5.9†† | 6 | 29.8 ± 9.8ns†† | 5.79 ± 11.4NS | 24.1 ± 40.6NS | 0.60 ± 1.02NS |
| 2-APB | 7 | 47.4 ± 6.1NS | 7 | 8.4 ± 7.5**††† | −38.98 ± 9.6†† | −82.2 ± 15.7††† | −1.52 ± 0.29††† |
Values are means ± SE. n, no. of perfused tubules; JCl, chloride absorption; ΔJCl, the differences in JCl between perfusion rates of 5 and 20 nl/min; ΔJCl/JCla*100, percent changes in chloride reabsorption from low flow rate. ns, Not significantly different from low flow rates in the same group.
Significant difference from low flow rates in the same group (*P < 0.05, **P < 0.01, ***P < 0.001). NS, not significantly different compared with control at the similar flow rates.
Significant difference compared with control at the similar flow rates (†P < 0.05, ††P < 0.01, †††P < 0.001).