Abstract
We investigated the role of Ca2+-activated K+
-channels
in the endothelial derived hyperpolarization-induced
renal vasodilation in vitro and in vivo in rats. Also,
the possible role of K+
- induced activation of inward
rectifier K+ (Kir) channels and Na+
/K+
-ATPase was
assessed. Furthermore, involvement of renal myoendothelial
gap junctions was evaluated in vitro.
Because assessment of endothelial derived hyperpolarization-induced
renal vasodilation in vivo is hampered
by experimental limitations, we have combined
in vivo and in vitro experiments. Isometric tension in
rat renal interlobar arteries was measured using a wire
myograph. Renal blood flow was measured in isoflurane
and pentobarbital anesthetized rats. The ACh-induced
response was measured before and after
inhibition of the nitric oxide synthase with L-NAME
and cyclooxygenase using indomethacin. Blockade of
small conductance Ca2+-activated K+
-channels (SKCa)
by apamin and intermediate conductance Ca2+-activated
K+
-channels (IKCa) by TRAM-34 significantly
decreased the endothelial derived hyperpolarization-induced
vasorelaxation in vitro but had no effect
in vivo. Inhibition of Kir-channels by Ba2+ and Na+
/
K+
-ATPases by ouabain significantly attenuated renal
vasorelaxation in vitro but had no effect in vivo. In
vitro, inhibition of gap junctions using carbenoxolone
or 18a-glycyrrhetinic acid significantly reduced the
endothelial derived hyperpolarization-induced vasorelaxation.
In conclusion we found that in vitro, renal
vascular SKCa and IKCa-channels are essential for the
endothelial derived hyperpolarization-induced vasorelaxation.
Furthermore, activation of Kir-channels,
Na+
/K+
-ATPases and vascular gap junctions play a significant
role in the renal vascular endothelial derived
hyperpolarization-response in vitro. In vivo the
endothelial derived hyperpolarization response seems
unaffected by the present blockade of various K+
channels.
| Original language | English |
|---|---|
| Journal | Acta Physiologica |
| Volume | 215 |
| Issue number | Suppl. 703 - Meeting abstract |
| Pages (from-to) | 13-13 |
| ISSN | 1748-1708 |
| Publication status | Published - 2015 |
| Event | Meeting on Endothelium-Dependent Hyperpolarizations in Health and Disease - Nyborg, Denmark Duration: 14 Sept 2015 → 17 Sept 2015 |
Workshop
| Workshop | Meeting on Endothelium-Dependent Hyperpolarizations in Health and Disease |
|---|---|
| Country/Territory | Denmark |
| City | Nyborg |
| Period | 14/09/2015 → 17/09/2015 |