Involvement of Na(+)-K(+)-2Cl(-) cotransporters in hypertonicity-induced rise in intracellular calcium concentration.
A hypertonic saline containing propylene glycol facilitates calcium (Ca(2+)) influx through voltage-dependent Ca(2+) channels. The present study performed experiments to elucidate the mechanism by which Na(+)-K(+)-2Cl(-) cotransporters participate in the rise in the intracellular calcium concentration ([Ca(2+)]i) under the hypertonic condition. Both furosemide and ethacryonic acid significantly decreased the [Ca(2+)]i raised by hypertonicity. Similarly, Na(+)-, K(+)-, or Cl(-)-free saline also reduced it. Both norepinephrine and dopamine significantly enhanced the rise in [Ca(2+)]i. In conclusion, the findings obtained indicate that the Na+-K+-2Cl- cotransporters evoke cell depolarization and that this depolarization raises the [Ca(2+)]i by activating voltage-dependent Ca(2+) channels.
Hattori
Toshimi
T
Department of Dental Pharmacology, Matsumoto Dental University, Shiojiri, Japan. hattori@po.mdu.ac.jp
Wang
Pao-Li
PL
D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002712:Chlorides / Q000493:pharmacokinetics; D004298:Dopamine / Q000494:pharmacology; D015259:Dopamine Agents / Q000494:pharmacology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004976:Ethacrynic Acid / Q000494:pharmacology; D005665:Furosemide / Q000494:pharmacology; D008564:Membrane Potentials / Q000187:drug effects / Q000502:physiology; D009474:Neurons / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D009638:Norepinephrine / Q000494:pharmacology; D016716:PC12 Cells; D011188:Potassium / Q000493:pharmacokinetics; D051381:Rats; D012462:Saline Solution, Hypertonic / Q000494:pharmacology; D012964:Sodium / Q000493:pharmacokinetics; D049994:Sodium Potassium Chloride Symporter Inhibitors / Q000494:pharmacology; D028021:Sodium-Potassium-Chloride Symporters / Q000378:metabolism*; D013566:Sympathomimetics / Q000494:pharmacology; D014882:Water-Electrolyte Balance / Q000187:drug effects / Q000502:physiology*
D002712:Chlorides; D015259:Dopamine Agents; D004791:Enzyme Inhibitors; D012462:Saline Solution, Hypertonic; D049994:Sodium Potassium Chloride Symporter Inhibitors; D028021:Sodium-Potassium-Chloride Symporters; D013566:Sympathomimetics; D005665:Furosemide; D012964:Sodium; D004976:Ethacrynic Acid; D011188:Potassium; D002118:Calcium; D004298:Dopamine; D009638:Norepinephrine