Effect of magnesium on sodium transport in toad urinary bladder.
Voltage-clamp techniques were employed to examine the effect of magnesium (Mg) on sodium transport in the isolated urinary bladder of the Dominican toad. Substitution of 1 mM Mg had no effect, but 3-mM Mg substitution resulted in a reversible increase in short-circuit current (27%) and potential difference (19%) and decrease in transepithelial resistance (14%); no greater effect was seen with 5- or 10-mM Mg substitution. The effect was produced by mucosal or mucosal and serosal Mg substitution; serosal Mg substitution was without effect. Analysis of electrical parameters disclosed that magnesium increased net sodium transport via an effect on the sodium pump.
D000818:Animals; D001692:Biological Transport / Q000187:drug effects; D002024:Bufo marinus; D005260:Female; D008274:Magnesium / Q000494:pharmacology*; D009092:Mucous Membrane / Q000378:metabolism; D012704:Serous Membrane / Q000378:metabolism; D012964:Sodium / Q000378:metabolism*; D001743:Urinary Bladder / Q000187:drug effects / Q000378:metabolism*
D012964:Sodium; D008274:Magnesium