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Properties of Ca 2+ oscillations in rat carotid body chemoreceptor cells
Author(s) -
Kim Donghee,
Hogan James O.
Publication year - 2018
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.2018.32.1_supplement.601.2
Subject(s) - carotid body , glomus cell , extracellular , hypoxia (environmental) , chemoreceptor , intracellular , medicine , endocrinology , biophysics , chemistry , perfusion , calcium , receptor , biology , stimulation , biochemistry , oxygen , organic chemistry
Hypoxia elevates intracellular Ca 2+ concentration ([Ca 2+ ]) in carotid body (CB) Type 1 (glomus) cells and thereby stimulates the secretory activity. To understand Ca 2+ signaling mechanisms in more detail, we examined the effects of a wide range of pO 2 on [Ca 2+ ]. Basal level of Ca 2+ oscillations were observed in normoxia. The frequency of Ca 2+ oscillations was highly dependent on perfusion temperature. At 37°C, >60% of cells showed spontaneous Ca 2+ oscillations. The mean frequency of Ca 2+ oscillations in O 2 ‐sensitive cells was ~0.5 per min. Severe hypoxia and anoxia (<20 mmHg) usually elicited a sustained elevation of [Ca 2+ ]. Mild and moderate levels of hypoxia (20–50 mmHg) caused an increase in the frequency of Ca 2+ oscillations by ~20% and ~60%, respectively. Ca 2+ oscillations were inhibited by 0.1 mM 2‐APB (an inhibitor of IP 3 receptor and store‐operated Ca 2+ entry), as well as by removal of extracellular Ca 2+ . Secretory activity was also blocked by 2‐APB and removal of extracellular Ca 2+ . Block of voltage‐dependent K+ channels with 3 mM TEA enhanced hypoxia‐induced increase in Ca 2+ oscillations by ~20%, indicating that Kv helps limit the Ca 2+ response to mild and moderate hypoxia. Our results show that an increase Ca 2+ oscillations, rather than a sustained rise in [Ca 2+ ], underlies the stimulatory effects of mild and moderate levels of hypoxia on glomus cell activity. Support or Funding Information Supported by NIHCa 2+ oscillationsThis abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal .