Regulation of mucociliary transport. Response of mucous cells to stimulation by amiloride applied to the frog palate in vitro.
Mucociliary transport (MCT) over the surface of isolated frog palatal epithelium was significantly inhibited by the diuretic drug amiloride (50% at 10(-5)M); this occurred when the drug was applied to the mucosal but not to the submucosal surface. The rate of ciliary beating was unchanged by treatment with amiloride (13.5 +/- 1.3 Hz, amiloride; 13.4 +/- 1.4 Hz, control). Spontaneous reversal of inhibition of MCT occurred after extended rinsing (1.5 to 3 h) with Ringer's solution; however, addition of mucus immediately restored MCT to control level. Amiloride applied to the mucosal surface stimulated 2.5 to 3 times as many cells to discharge mucus; this was correlated with an increase of 28% in apparent viscoelasticity of the mucus transport layer measured in situ (approximated by determining breaking strength of mucus using a surface tension balance). Other effects of mucosal application of amiloride included reduction of the transepithelial electrical potential by 62% and increased sodium (17%) in secreted mucus. This is the first report of a stimulatory effect by amiloride on mucous secretory cells.
D000584:Amiloride / Q000494:pharmacology*; D000818:Animals; D001692:Biological Transport / Q000187:drug effects; D002923:Cilia / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D004848:Epithelium / Q000502:physiology; D066298:In Vitro Techniques; D008564:Membrane Potentials / Q000187:drug effects; D009061:Mouth Mucosa / Q000166:cytology / Q000378:metabolism*; D009093:Mucus / Q000378:metabolism; D010159:Palate / Q000166:cytology / Q000378:metabolism*; D011719:Pyrazines / Q000494:pharmacology*; D011898:Ranidae
D011719:Pyrazines; D000584:Amiloride