Details
| Original language | English |
|---|---|
| Pages (from-to) | 1215-1222 |
| Number of pages | 8 |
| Journal | Pflugers Archiv European Journal of Physiology |
| Volume | 468 |
| Issue number | 7 |
| Early online date | 31 Mar 2016 |
| Publication status | Published - Jul 2016 |
Abstract
Using the double whole-cell patch-clamp technique, we found that the absence of intracellular ATP led to gap junction uncoupling in cochlear-supporting Hensen cells. The uncoupling was observed as a progressive reduction of the gap junctional electrical conductance from a starting value of approximately 40 nS to less than 0.04 nS within 10-20 min. The conductance rundown was partly avoided by at least 3 mM ATP and completely suppressed by 5 mM ATP or 5'-adenylyl-imidodiphosphate (AMP-PNP), the non-hydrolysable ATP analog, in the pipette filling solution, suggesting that ATP was needed as ligand and not as a hydrolysable energy supplier or substrate for enzymatic reactions. The effect of intracellular ATP was mimicked by the external application of barium, a nonselective blocker of inwardly rectifying K(+) (Kir) channels, and glibenclamide, an inhibitor of the ATP-sensitive Kir channels (KATP). Moreover a Ba(2+)-sensitive whole-cell inward current was observed in absence of internal ATP. We propose that the internal ATP kept the KATP channels in a closed state, thereby maintaining the gap junction coupling of Hensen cells. The immunostaining of guinea pig cochlear tissue revealed for the first time the expression of the KATP channel subunits Kir6.1 and SUR1 in Hensen cells and supported the proposed hypothesis. The results suggest that KATP channels, as regulator of the gap junction coupling in Hensen cells, could be the physiological link between the metabolic state of the supporting cells and K(+) recycling in the organ of Corti.
Keywords
- Adenosine Monophosphate/metabolism, Adenosine Triphosphate/metabolism, Animals, Cochlea/drug effects, Electrophysiology/methods, Gap Junctions/drug effects, Glyburide/pharmacology, Guinea Pigs, KATP Channels/metabolism, Membrane Potentials/drug effects, Potassium/metabolism, Potassium Channels, Inwardly Rectifying/metabolism, Sulfonylurea Receptors/metabolism, Hensen cells, SUR1, Gap junction, Kir6.1, Cochlea, Double whole-cell patch-clamp, ATP-sensitive K channels
ASJC Scopus subject areas
- Medicine(all)
- Physiology (medical)
- Biochemistry, Genetics and Molecular Biology(all)
- Physiology
- Biochemistry, Genetics and Molecular Biology(all)
- Clinical Biochemistry
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In: Pflugers Archiv European Journal of Physiology, Vol. 468, No. 7, 07.2016, p. 1215-1222.
Research output: Contribution to journal › Article › Research › peer review
}
TY - JOUR
T1 - ATP-sensitive K(+) channels (Kir6.1/SUR1) regulate gap junctional coupling in cochlear-supporting cells
AU - Blödow, Alexander
AU - Begandt, Daniela
AU - Bader, Almke
AU - Becker, Annegret
AU - Burghard, Alice
AU - Kühne, Daniela
AU - Kral, Andrej
AU - Ngezahayo, Anaclet
PY - 2016/7
Y1 - 2016/7
N2 - Using the double whole-cell patch-clamp technique, we found that the absence of intracellular ATP led to gap junction uncoupling in cochlear-supporting Hensen cells. The uncoupling was observed as a progressive reduction of the gap junctional electrical conductance from a starting value of approximately 40 nS to less than 0.04 nS within 10-20 min. The conductance rundown was partly avoided by at least 3 mM ATP and completely suppressed by 5 mM ATP or 5'-adenylyl-imidodiphosphate (AMP-PNP), the non-hydrolysable ATP analog, in the pipette filling solution, suggesting that ATP was needed as ligand and not as a hydrolysable energy supplier or substrate for enzymatic reactions. The effect of intracellular ATP was mimicked by the external application of barium, a nonselective blocker of inwardly rectifying K(+) (Kir) channels, and glibenclamide, an inhibitor of the ATP-sensitive Kir channels (KATP). Moreover a Ba(2+)-sensitive whole-cell inward current was observed in absence of internal ATP. We propose that the internal ATP kept the KATP channels in a closed state, thereby maintaining the gap junction coupling of Hensen cells. The immunostaining of guinea pig cochlear tissue revealed for the first time the expression of the KATP channel subunits Kir6.1 and SUR1 in Hensen cells and supported the proposed hypothesis. The results suggest that KATP channels, as regulator of the gap junction coupling in Hensen cells, could be the physiological link between the metabolic state of the supporting cells and K(+) recycling in the organ of Corti.
AB - Using the double whole-cell patch-clamp technique, we found that the absence of intracellular ATP led to gap junction uncoupling in cochlear-supporting Hensen cells. The uncoupling was observed as a progressive reduction of the gap junctional electrical conductance from a starting value of approximately 40 nS to less than 0.04 nS within 10-20 min. The conductance rundown was partly avoided by at least 3 mM ATP and completely suppressed by 5 mM ATP or 5'-adenylyl-imidodiphosphate (AMP-PNP), the non-hydrolysable ATP analog, in the pipette filling solution, suggesting that ATP was needed as ligand and not as a hydrolysable energy supplier or substrate for enzymatic reactions. The effect of intracellular ATP was mimicked by the external application of barium, a nonselective blocker of inwardly rectifying K(+) (Kir) channels, and glibenclamide, an inhibitor of the ATP-sensitive Kir channels (KATP). Moreover a Ba(2+)-sensitive whole-cell inward current was observed in absence of internal ATP. We propose that the internal ATP kept the KATP channels in a closed state, thereby maintaining the gap junction coupling of Hensen cells. The immunostaining of guinea pig cochlear tissue revealed for the first time the expression of the KATP channel subunits Kir6.1 and SUR1 in Hensen cells and supported the proposed hypothesis. The results suggest that KATP channels, as regulator of the gap junction coupling in Hensen cells, could be the physiological link between the metabolic state of the supporting cells and K(+) recycling in the organ of Corti.
KW - Adenosine Monophosphate/metabolism
KW - Adenosine Triphosphate/metabolism
KW - Animals
KW - Cochlea/drug effects
KW - Electrophysiology/methods
KW - Gap Junctions/drug effects
KW - Glyburide/pharmacology
KW - Guinea Pigs
KW - KATP Channels/metabolism
KW - Membrane Potentials/drug effects
KW - Potassium/metabolism
KW - Potassium Channels, Inwardly Rectifying/metabolism
KW - Sulfonylurea Receptors/metabolism
KW - Hensen cells
KW - SUR1
KW - Gap junction
KW - Kir6.1
KW - Cochlea
KW - Double whole-cell patch-clamp
KW - ATP-sensitive K channels
UR - http://www.scopus.com/inward/record.url?scp=84962280821&partnerID=8YFLogxK
U2 - 10.1007/s00424-016-1815-8
DO - 10.1007/s00424-016-1815-8
M3 - Article
C2 - 27030354
VL - 468
SP - 1215
EP - 1222
JO - Pflugers Archiv European Journal of Physiology
JF - Pflugers Archiv European Journal of Physiology
SN - 0031-6768
IS - 7
ER -