Developmental changes in intracellular Ca2+ response of carotid chemoreceptor cells to hypoxia

L. M. Sterni, O. S. Bamford, S. M. Tomares, M. H. Montrose, J. L. Carroll

Research output: Contribution to journalArticlepeer-review

Abstract

The carotid chemoreceptor response to hypoxia is weak just after birth and increases during postnatal development. The mechanisms underlying chemoreceptor maturation are unknown. We tested the hypothesis that carotid chemoreceptor maturation occurs at the glomus cell level by measuring intracellular calcium ([Ca2+](i)) mobilization in response to hypoxia, anoxia, and NaCN in freshly dissociated cells from newborn vs. adult rabbit carotid bodies. Cells were loaded with fura 2 and superfused at 37°C with balanced salt solution equilibrated with 5% CO2. [Ca2+](i) mobilization in response to 3-min challenges of hypoxia (PO2 ~15 mmHg), anoxia (PO2 ~0 mmHg), and NaCN (1 mM) was measured using a digital imaging microscope. The fluorescence intensity ratio was used to calculate [Ca2+](i). Peak [Ca2+](i) responses to all three challenges were three- to fivefold greater in glomus cells from adult compared with newborn carotid chemoreceptors. In addition, the average normoxic [Ca2+](i) baseline was approximately threefold higher in the adult glomus cells. These results suggest that carotid chemoreceptor glomus cell sensitivity to natural stimuli, as reflected by the [Ca2+](i) response, depends on the level of postnatal maturity.

Original languageEnglish (US)
Pages (from-to)L801-L808
JournalAmerican Journal of Physiology - Lung Cellular and Molecular Physiology
Volume268
Issue number5 12-5
DOIs
StatePublished - Jan 1 1995

Keywords

  • carotid body
  • control of breathing
  • fluorescence imaging
  • fura 2
  • rabbit

ASJC Scopus subject areas

  • Physiology
  • Pulmonary and Respiratory Medicine
  • Physiology (medical)
  • Cell Biology

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