Magnesium regulates ion transport across canine tracheal epithelium.
We examined the effect of Mg2+ on potential difference (PD) and short circuit current (SCC) of the posterior epithelial membrane of canine trachea using an Ussing chamber. After the exchange to a Mg(2+)-free solution, PD and SCC rapidly increased, reaching maximal values within 3 min, followed by a gradual return towards the baseline over 60 min. In a Ca(2+)-free solution, Mg2+ removal did not alter PD and SCC values. Increased Mg2+ in the solution produced significant gradual decreases in PD and SCC. The decreases in PD and SCC were reversed by the addition of excessive Ca2+ to the solution. Mg2+ removal did not alter significantly isoproterenol-induced increases in PD and SCC values, while increased Mg2+ significantly reduced the increases. These findings indicate that extracellular Mg2+ is an important determinant in ion transport across the airway epithelium, probably through antagonistic actions of Mg2+ and Ca2+.
Satoh
M
M
First Department of Internal Medicine, Tohoku University School of Medicine, Sendai, Japan.
Shimura
S
S
Sasaki
T
T
Yamamoto
M
M
Okayama
H
H
Takishima
T
T
Shirato
K
K
D000584:Amiloride / Q000494:pharmacology; D000818:Animals; D001692:Biological Transport / Q000187:drug effects; D004285:Dogs; D004594:Electrophysiology; D004848:Epithelium / Q000378:metabolism / Q000502:physiology; D005260:Female; D007477:Ions; D007545:Isoproterenol / Q000494:pharmacology; D008274:Magnesium / Q000494:pharmacology*; D015636:Magnesium Chloride / Q000494:pharmacology; D008297:Male; D009994:Osmolar Concentration; D026941:Sodium Channel Blockers; D014132:Trachea / Q000378:metabolism* / Q000502:physiology
D007477:Ions; D026941:Sodium Channel Blockers; D015636:Magnesium Chloride; D000584:Amiloride; D008274:Magnesium; D007545:Isoproterenol