Phorbol ester and okadaic acid regulation of Na-2Cl-K cotransport in rabbit tracheal epithelial cells.
We evaluated a role for protein kinase C (PKC) in the regulation of rabbit tracheal epithelial Na-Cl(K) cotransport. Short-term treatment with phorbol 12-myristate 13-acetate (PMA) dose dependently increased bumetanide-sensitive Na and Cl efflux and elevated staurosporine- and bumetanide-sensitive Na, Cl, and K uptake. PMA and the alpha 2A-adrenergic agonist guanabenz both induced contransport with a stoichiometry of 2 Cl:1 Na and 2 Cl:1 Rb and elevated staurosporine-sensitive PKC activity in cytosolic and particulate fractions. Prolonged PMA treatment did not sustain bumetanide-sensitive 2 Cl:1 Na and 2 Cl:1 Rb transport but did block stimulation of bumetanide-sensitive transport by PMA or guanabenz and elevation of PKC activity by PMA and guanabenz in a particulate fraction. Cells treated with okadaic acid exhibited a staurosporine- and bumetanide-sensitive 2 Cl:1 Na and 2 Cl:1 Rb uptake. In cultured monolayers, basolateral perfusion with epinephrine, isoproterenol, or PMA increased short-circuit current (Isc). Basolateral application of bumetanide reduced elevated Isc to baseline levels, indicating a role for Cl secretory cells in a reconstituted tracheal epithelium. Pretreatment of transmonolayer cultures with PMA diminished the stimulatory response to epinephrine. These results indicate that, in rabbit tracheal epithelial cells, alpha-adrenergic stimulation activated Na-2Cl-K cotransport and that PKC is a critical effector in this process.
Liedtke
C M
CM
Department of Pediatrics, Rainbow Babies and Children Hospital, Cleveland, Ohio, USA.
Thomas
L
L
D000818:Animals; D002034:Bumetanide / Q000494:pharmacology; D002352:Carrier Proteins / Q000378:metabolism*; D002478:Cells, Cultured; D004553:Electric Conductivity; D004847:Epithelial Cells; D004848:Epithelium / Q000378:metabolism / Q000502:physiology; D008297:Male; D019319:Okadaic Acid / Q000494:pharmacology*; D010749:Phosphoprotein Phosphatases / Q000378:metabolism; D011493:Protein Kinase C / Q000378:metabolism; D011817:Rabbits; D028021:Sodium-Potassium-Chloride Symporters; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology*; D013997:Time Factors; D014132:Trachea / Q000166:cytology / Q000378:metabolism* / Q000502:physiology
D002352:Carrier Proteins; D028021:Sodium-Potassium-Chloride Symporters; D002034:Bumetanide; D019319:Okadaic Acid; D011493:Protein Kinase C; D010749:Phosphoprotein Phosphatases; D013755:Tetradecanoylphorbol Acetate