title: Regulation of mucociliary transport. Response of mucous cells to stimulation by amiloride applied to the frog palate in vitro.
abstract: 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.
mesh_terms: 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
chemical_list: D011719:Pyrazines; D000584:Amiloride