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Exposure to intermittent hypoxia for 7 days does not alter the intracellular pH response of NTS neurons to hypercapnic acidosis
Author(s) -
Luo Zili,
Mifflin Steve
Publication year - 2011
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.25.1_supplement.669.5
The nucleus of the solitary tract (NTS) contains neurons whose action potential discharge rate can either increase or decrease when exposed to hypercapnic acidosis (HA). The present study was designed to investigate if the responses of neurons in caudal NTS to HA are altered after 7 days exposure to intermittent hypoxia (IH). Brain stem slices containing the NTS were obtained from adult rats maintained in a normoxic environment and rats exposed to IH (8am and 4pm alternate 21% and 10%O 2 for 3 min of every 10 min for 7 days to mimic the arterial hypoxemia that occurs during sleep apnea). Intracellular pH (pHi) was measured using 2′, 7′‐bis(carboxyethyl)‐5(6)‐carboxyfluorescein‐acetomethyl ester (BCECF‐AM) before, during and after inducing HA by switching superfusion of the slice from an aCSF gassed with 95% O2 and 5% CO2 to aCSF gassed with 85% O2 and 15% CO2. HA reduced the pH i of NTS neurons from 7.45 ± 0.01 to 7.25 ± 0.01 in the normoxic group (n=28 neurons measured in slices from 10 rats) and from 7.46 ± 0.01 to 7.26 ± 0.02 in the IH exposed group (n=18 neurons measured in slices from 5 rats). The data indicate that exposures to IH do not alter the level of intracellular acidification of neurons within NTS during HA.