Changes in oxygen sensitivity of TASK in carotid body glomus cells during early postnatal development

Respir Physiol Neurobiol. 2011 Aug 15;177(3):228-35. doi: 10.1016/j.resp.2011.04.012. Epub 2011 Apr 16.

Abstract

A post-natal increase in carotid body (CB) hypoxia responsiveness occurs at the level of carotid sinus nerve activity, intracellular calcium, cell membrane depolarization and hypoxic inhibition of O(2)-sensitive background K(+) conductance. TASK-1, TASK-1/3 and TASK-3 are functionally expressed in CB glomus cells, with TASK-1/3 providing the major part of the O(2)-sensitive TASK-like background K(+) conductance. Here we report the effects of graded hypoxia on TASK-like channel activity in CB glomus cells from rats aged 0 to 1, 6 to 7 and 16 to 18 days; the time frame of postnatal CB functional maturation. TASK was active in nearly all cell-attached patches and TASK activity during normoxia did not differ across ages. Hypoxia produced a progressive decrease in channel opening frequency with graded decreases in O(2) level and also produced glomus cell depolarization, as assessed by the shift in reversal potential of TASK single channel current. Hypoxic inhibition of TASK activity was least at P0-P1 and increased with age mainly between 6-7 and 16-18 days. The O(2)-sensitive TASK activity was significantly greater in glomus cells from P16 to P18 when compared to cells from P0 to P1 day old rats. These results support the hypothesis that postnatal carotid body functional maturation is due, at least in part, to changes in the sensitivity of TASK to the hypoxic signals generated in glomus cells.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Age Factors
  • Analysis of Variance
  • Animals
  • Animals, Newborn
  • Biophysics
  • Carotid Body / cytology*
  • Carotid Body / growth & development*
  • Cell Hypoxia / drug effects
  • Cell Hypoxia / physiology*
  • Cells, Cultured
  • Chemoreceptor Cells / drug effects
  • Chemoreceptor Cells / physiology*
  • Electric Stimulation
  • Gene Expression Regulation, Developmental / physiology
  • Membrane Potentials / drug effects
  • Membrane Potentials / physiology
  • Nerve Tissue Proteins
  • Oxygen / metabolism*
  • Oxygen / pharmacology
  • Patch-Clamp Techniques
  • Potassium Channels, Tandem Pore Domain / metabolism*
  • Rats

Substances

  • Nerve Tissue Proteins
  • Potassium Channels, Tandem Pore Domain
  • potassium channel subfamily K member 3
  • Oxygen