Comparative aspects of actions of a short-chain phospholipid on epithelial Na+ channels and tight junction conductance.
Ion transport in both the frog skin (a high-resistance epithelium) and the rabbit nasal airway epithelium (a low-resistance epithelium) are dominated by electrogenic Na+ absorption via apical membrane amiloride-sensitive Na+ channels, and short-circuit current (ISC) is essentially a measure of Na+ absorption in both epithelia. In both epithelia, mucosal application of the short-chain phospholipid didecanoyl-L-alpha-phosphatidylcholine (DDPC) dose-dependently inhibited the amiloride-sensitive ISC and caused an initial decrease in epithelial conductance (Gt) followed by an increase in Gt to steady-state values above control level. The effects were reversible. It is concluded that DDPC (a) inhibits epithelial amiloride-sensitive Na+ channels and (b) induces an increase in paracellular tight junction conductance. These effects may involve changes in non-specific lipid-protein interactions at the cell membrane level.
Röpke
M
M
Department of Medical Physiology, Panum Institute, University of Copenhagen, Denmark.
Unmack
M A
MA
Willumsen
N J
NJ
Frederiksen
O
O
D000818:Animals; D004848:Epithelium / Q000502:physiology; D009297:Nasal Mucosa / Q000502:physiology; D009431:Neural Conduction / Q000502:physiology*; D010713:Phosphatidylcholines / Q000494:pharmacology; D010743:Phospholipids / Q000502:physiology*; D011817:Rabbits / Q000502:physiology*; D011896:Rana temporaria / Q000502:physiology*; D012879:Skin Physiological Phenomena; D015222:Sodium Channels / Q000502:physiology*; D019108:Tight Junctions / Q000502:physiology*
D010713:Phosphatidylcholines; D010743:Phospholipids; D015222:Sodium Channels; C015132:1,2-didecanoylphosphatidylcholine