Alveolar fluid clearance in late-gestational guinea pigs after labor induction: mechanisms and regulation

Title

Alveolar fluid clearance in late-gestational guinea pigs after labor induction: mechanisms and regulation

Creator

Norlin A; Folkesson H G

Publisher

American Journal of Physiology-Lung Cellular and Molecular Physiology

Date

2001
2001-04

Description

We tested the hypothesis that labor-induced epinephrine release would stimulate alveolar fluid clearance in preterm fetuses. Preterm fetuses were obtained by cesarean section from timed-pregnant guinea pigs at 61-69 days postconception. Fetal guinea pigs were euthanized and placed on continuous positive airway pressure oxygenation, and an isosmolar 5% albumin solution was instilled. Alveolar fluid clearance was measured over 1 h. The fetal lung began to absorb fluid at 64-66 days postconception, and at birth, alveolar fluid clearance quadrupled. Baseline alveolar fluid clearance when present was sensitive to propranolol inhibition and depended on beta -adrenergic stimulation. Measurements of plasma epinephrine in fetal animals confirmed high epinephrine levels in 66- to 69-day postconception fetuses. Prenatal alveolar fluid clearance when present was highly amiloride sensitive, suggesting that amiloride-sensitive Na+ channels were critical. Oxytocin-induced labor initiated an amiloride- and propranolol-sensitive net alveolar fluid clearance in 61-day-gestation animals. Moreover, oxytocin induced significant epinephrine release in all fetuses. These results have clinical implications for infants delivered by cesarean section before the onset of labor. Use of pharmacological agents to induce labor may reduce the occurrence and severity of perinatal respiratory distress.

Subject

absorption; adrenaline; alveolar epithelium; beta-adrenergic stimulation; birth; catecholamines; developmental-changes; distress syndrome; epinephrine; fetal sheep; infant respiratory; lung liquid clearance; newborn rabbits; Physiology; prenatal development; Respiratory System; sodium transport; transport; ventilated rats

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

L606-L616

Issue

4

Volume

280

Citation

Norlin A; Folkesson H G, “Alveolar fluid clearance in late-gestational guinea pigs after labor induction: mechanisms and regulation,” NEOMED Bibliography Database, accessed May 7, 2021, https://neomed.omeka.net/items/show/6652.

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