title: Ion transport in cultured fetal and adult rabbit tracheal epithelia.
abstract: Transepithelial potential difference (Vte), short circuit current (Isc), and transepithelial resistance (Rte) were measured to assess Na+ and Cl- transport in cultured tracheal epithelial cells from fetal and adult rabbits. Cultured fetal and adult cells developed differentiated morphology as determined by electron microscopy. Base-line Vte, Isc, and Rte were equivalent in late gestation (28-30 days) and adult cultures. Amiloride (10(-4) M) (Na+ transport inhibitor) reduced Isc by 7.4 +/- 1.2 microA/cm2 (24%) in adult cultures but only by 1.8 +/- 0.7 microA/cm2 (7%) in fetal cultures (P less than 0.001). Furosemide (10(-4) M) (Cl- transport inhibitor) diminished Isc by 16.5 +/- 3.2 microA/cm2 (53%) in adult cultures and 18.8 +/- 2.8 microA/cm2 (74%) in fetal cultures (P less than 0.01). Epinephrine (10(-6) M) stimulated Isc by 24.2 +/- 5.8 microA/cm2 (72%) in adult cells but only by 7.0 +/- 1.1 microA/cm2 (32%) in fetal cells (P less than 0.05). After epinephrine exposure, furosemide-sensitive Isc increased to 41.5 +/- 7.7 microA/cm2 in adult cells but remained unchanged in fetal cells (P less than 0.001). Our results suggest that fetal cells absorb less Na+ and secrete more Cl- than adult cells and that the Cl- secretory response to epinephrine is greater in adult than in fetal cells.
authors.affiliation: Department of Physiology, Johns Hopkins University School of Medicine, Baltimore, Maryland.
authors.forename: P L
authors.initials: PL
authors.lastname: Zeitlin
authors.forename: G M
authors.initials: GM
authors.lastname: Loughlin
authors.forename: W B
authors.initials: WB
authors.lastname: Guggino
mesh_terms: D000584:Amiloride / Q000494:pharmacology; D000818:Animals; D001693:Biological Transport, Active; D002712:Chlorides / Q000378:metabolism*; D004594:Electrophysiology; D004837:Epinephrine / Q000494:pharmacology; D004848:Epithelium / Q000378:metabolism; D005260:Female; D008854:Microscopy, Electron; D011247:Pregnancy; D011817:Rabbits; D011943:Receptors, Adrenergic, beta / Q000378:metabolism; D012964:Sodium / Q000378:metabolism*; D014132:Trachea / Q000378:metabolism*
chemical_list: D002712:Chlorides; D011943:Receptors, Adrenergic, beta; D000584:Amiloride; D012964:Sodium; D004837:Epinephrine