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Ca(2+)-dependent stimulation of alveolar fluid clearance in near-term fetal guinea pigs.

Norlin, Andreas and Folkesson, Hans LU (2002) In American Journal of Physiology: Lung Cellular and Molecular Physiology 282(4). p.642-649
Abstract
We investigated the importance of changes in intracellular Ca(2+) concentration ([Ca(2+)](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 plus minus 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(minus sign3) M).... (More)
We investigated the importance of changes in intracellular Ca(2+) concentration ([Ca(2+)](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 plus minus 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(minus sign3) M). Inhibition of membrane Ca(2+) channels by verapamil (10(minus sign4) M) or depletion of intracellular Ca(2+) by thapsigargin (10(minus sign5) 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 Ca(2+) may act as a second messenger in mediating catecholamine-stimulated AFC. (Less)
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keywords
Ca(2+)-Transporting ATPase/antagonists & inhibitors/metabolism, Calcium/metabolism/*pharmacokinetics, Calcium Channel Blockers/pharmacology, Diuretics/pharmacology, Enzyme Inhibitors/pharmacology, Extravascular Lung Water/*metabolism, Female, Fetus/metabolism, Gestational Age, Guinea Pigs, Oxytocin/pharmacology, Pregnancy, Pulmonary Alveoli/*embryology/*metabolism, Sodium/metabolism, Support, Non-U.S. Gov't, Verapamil/pharmacology, Thapsigargin/pharmacology, Animal, Amiloride/pharmacology
in
American Journal of Physiology: Lung Cellular and Molecular Physiology
volume
282
issue
4
pages
642 - 649
publisher
American Physiological Society
external identifiers
  • wos:000174231500006
  • pmid:11880288
  • scopus:0036550601
ISSN
1522-1504
DOI
10.1152/ajplung.00417.2000
language
English
LU publication?
yes
id
a0067def-f4a1-4593-afd9-d1af35edc799 (old id 106281)
alternative location
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=11880288&dopt=Abstract
date added to LUP
2007-07-23 12:54:22
date last changed
2017-10-22 03:51:13
@article{a0067def-f4a1-4593-afd9-d1af35edc799,
  abstract     = {We investigated the importance of changes in intracellular Ca(2+) concentration ([Ca(2+)](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 plus minus 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(minus sign3) M). Inhibition of membrane Ca(2+) channels by verapamil (10(minus sign4) M) or depletion of intracellular Ca(2+) by thapsigargin (10(minus sign5) 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 Ca(2+) may act as a second messenger in mediating catecholamine-stimulated AFC.},
  author       = {Norlin, Andreas and Folkesson, Hans},
  issn         = {1522-1504},
  keyword      = {Ca(2+)-Transporting ATPase/antagonists & inhibitors/metabolism,Calcium/metabolism/*pharmacokinetics,Calcium Channel Blockers/pharmacology,Diuretics/pharmacology,Enzyme Inhibitors/pharmacology,Extravascular Lung Water/*metabolism,Female,Fetus/metabolism,Gestational Age,Guinea Pigs,Oxytocin/pharmacology,Pregnancy,Pulmonary Alveoli/*embryology/*metabolism,Sodium/metabolism,Support,Non-U.S. Gov't,Verapamil/pharmacology,Thapsigargin/pharmacology,Animal,Amiloride/pharmacology},
  language     = {eng},
  number       = {4},
  pages        = {642--649},
  publisher    = {American Physiological Society},
  series       = {American Journal of Physiology: Lung Cellular and Molecular Physiology},
  title        = {Ca(2+)-dependent stimulation of alveolar fluid clearance in near-term fetal guinea pigs.},
  url          = {http://dx.doi.org/10.1152/ajplung.00417.2000},
  volume       = {282},
  year         = {2002},
}