Cyclic AMP-induced mucin exocytosis is independent of Cl- movements in human colonic epithelial cells (HT29-Cl.16E).
The human colonic epithelial goblet cell line HT29-Cl.16E was used to test whether stimulated Cl- transport is involved in the mucin exocytotic response to an increase in intracellular cyclic AMP by measuring in parallel the short-circuit current (Isc) and mucin exocytosis. Addition of 50 microM forskolin to HT29-Cl.16E cells resulted in a 2-fold stimulation of mucin release and an increase in Isc by 20 microA/cm2. To evaluate the requirement for cosecretion of Cl-, the Cl- flux was altered by three different manipulations: (1) Cl- in the medium was replaced by the poorly transported anion gluconate; (2) basolateral Cl- influx through the Na(+)-K(+)-2Cl- cotransporter was inhibited by bumetanide; and (3) an inward Cl- flux through the apical plasma membrane was generated by reversing the Cl- gradient. These manipulations did not change the forskolin-stimulated mucin release and thereby provide evidence that Cl- movements are not required for fusion of mucin granules with the plasma membrane.
Jarry
A
A
Groupe de Recherche 'Fonctions Sécrétoires des Epithéliums Digestifs' (CJF INSERM 94-04), Nantes, France.
Merlin
D
D
Hopfer
U
U
Laboisse
C L
CL
D000666:Amphotericin B / Q000031:analogs & derivatives / Q000494:pharmacology; D001692:Biological Transport; D002352:Carrier Proteins / Q000037:antagonists & inhibitors; D002463:Cell Membrane Permeability / Q000187:drug effects; D002478:Cells, Cultured; D002712:Chlorides / Q000378:metabolism / Q000493:pharmacokinetics* / Q000502:physiology; D005576:Colforsin / Q000494:pharmacology; D003106:Colon / Q000166:cytology / Q000378:metabolism / Q000502:physiology*; D003470:Culture Media; D000242:Cyclic AMP / Q000378:metabolism / Q000502:physiology*; D004847:Epithelial Cells; D004848:Epithelium / Q000378:metabolism; D005089:Exocytosis / Q000187:drug effects / Q000502:physiology*; D006801:Humans; D007413:Intestinal Mucosa / Q000378:metabolism; D007424:Intracellular Fluid / Q000378:metabolism; D008564:Membrane Potentials / Q000187:drug effects / Q000502:physiology; D009077:Mucins / Q000378:metabolism*; D028021:Sodium-Potassium-Chloride Symporters; D013268:Stimulation, Chemical
D002352:Carrier Proteins; D002712:Chlorides; D003470:Culture Media; D009077:Mucins; D028021:Sodium-Potassium-Chloride Symporters; D005576:Colforsin; C041989:amphotericin A; D000666:Amphotericin B; D000242:Cyclic AMP