Alveolar epithelial ion and fluid transport - Ca2(+)-dependent stimulation of alveolar fluid clearance in near-term fetal guinea pigs

Title

Alveolar epithelial ion and fluid transport - Ca2(+)-dependent stimulation of alveolar fluid clearance in near-term fetal guinea pigs

Creator

Norlin A; Folkesson H G

Publisher

American Journal of Physiology-Lung Cellular and Molecular Physiology

Date

2002
2002-04

Description

We investigated the importance of changes in intracellular Ca2+ concentration ([Ca2+](i)) for amiloride-sensitive alveolar fluid clearance (AFC) in late-gestational guinea pigs. Fetal guinea pigs of 61, 68, and 69 days (term) gestation were investigated under normal conditions and after oxytocin-induced preterm labor. AFC or alveolar fluid secretion was measured using an impermeable tracer technique. At 61 days gestation there was net secretion of fluid into the lungs, and at birth the lungs cleared 49 +/- 7% of the instilled fluid volume over 1 h. Induction of preterm labor with oxytocin induced AFC at 61 days gestation. When present, AFC was inhibited or reversed to net fluid secretion by amiloride (10(-3) M). Inhibition of membrane Ca2+ channels by verapamil (10(-4) M) or depletion of intracellular Ca2+ by thapsigargin (10(-5) M) reduced AFC when net AFC was evident. Amiloride lacked an inhibitory effect on AFC when instilled with verapamil or thapsigargin. The results indicate that AFC via amiloride-sensitive pathways develops during late gestation, and that inducing preterm labor precociously may activate such pathways. Our results suggest that Ca2+ may act as a second messenger in mediating catecholamine-stimulated AFC.

Subject

adrenaline; agonist; amiloride; birth; blood-flow; cation; channel; distal lung epithelium; expression; lamb; liquid; oxytocin-induced preterm labor; Physiology; protein clearance; Respiratory System; sodium transport; surfactant secretion

Format

Journal Article

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Rights

Article information provided for research and reference use only. All rights are retained by the journal listed under publisher and/or the creator(s).

Pages

L642-L649

Issue

4

Volume

282

Citation

Norlin A; Folkesson H G, “Alveolar epithelial ion and fluid transport - Ca2(+)-dependent stimulation of alveolar fluid clearance in near-term fetal guinea pigs,” NEOMED Bibliography Database, accessed October 28, 2021, https://neomed.omeka.net/items/show/6653.

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