Mechanisms of bicarbonate secretion: lessons from the airways.
Early studies showed that airway cells secrete HCO(3)(-) in response to cAMP-mediated agonists and HCO(3)(-) secretion was impaired in cystic fibrosis (CF). Studies with Calu-3 cells, an airway serous model with high expression of CFTR, also show the secretion of HCO(3)(-) when cells are stimulated with cAMP-mediated agonists. Activation of basolateral membrane hIK-1 K(+) channels inhibits HCO(3)(-) secretion and stimulates Cl(-) secretion. CFTR mediates the exit of both HCO(3)(-) and Cl(-) across the apical membrane. Entry of HCO(3)(-) on a basolateral membrane NBC or Cl(-) on the NKCC determines which anion is secreted. Switching between these two secreted anions is determined by the activity of hIK-1 K(+) channels.
Department of Physiology and Biophysics, Rosalind Franklin University of Medicine and Sciences, North Chicago, IL 60064, USA. bob.bridges@rosalindfranklin.edu
Robert J
RJ
Bridges
D001562:Benzimidazoles / Q000494:pharmacology; D001639:Bicarbonates / Q000037:antagonists & inhibitors / Q000378:metabolism*; D001980:Bronchi / Q000166:cytology / Q000378:metabolism*; D002118:Calcium / Q000378:metabolism; D002120:Calcium Channel Agonists / Q000494:pharmacology; D015220:Calcium Channels / Q000187:drug effects; D002460:Cell Line; D005576:Colforsin / Q000494:pharmacology; D000242:Cyclic AMP / Q000037:antagonists & inhibitors; D003550:Cystic Fibrosis / Q000378:metabolism; D019005:Cystic Fibrosis Transmembrane Conductance Regulator / Q000378:metabolism / Q000502:physiology*; D017097:Electric Impedance; D006801:Humans; D051660:Intermediate-Conductance Calcium-Activated Potassium Channels / Q000187:drug effects / Q000502:physiology; D008564:Membrane Potentials / Q000187:drug effects; D008839:Microelectrodes; D012704:Serous Membrane / Q000187:drug effects
D001562:Benzimidazoles; D001639:Bicarbonates; C505032:CFTR protein, human; D002120:Calcium Channel Agonists; D015220:Calcium Channels; D051660:Intermediate-Conductance Calcium-Activated Potassium Channels; D019005:Cystic Fibrosis Transmembrane Conductance Regulator; D005576:Colforsin; D000242:Cyclic AMP; C102635:1-ethyl-2-benzimidazolinone; D002118:Calcium