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Spike frequency adaptation in avian intrapulmonary chemoreceptors does not rely on Na + /H + exchange (1092.9)
Author(s) -
Sheridan Krystal,
Hempleman Steven,
Lonjaret JeanGuillaume,
Meehan Shane,
Bassett Peter
Publication year - 2014
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.28.1_supplement.1092.9
Subject(s) - tonic (physiology) , chemistry , chemoreceptor , intracellular ph , biophysics , amiloride , intracellular , control of respiration , medicine , respiratory system , endocrinology , anesthesia , biochemistry , sodium , biology , receptor , organic chemistry
IPC are essential for avian breath‐by‐breath respiratory control and are inversely sensitive to lung P CO2 . Evidence suggests IPC detect intracellular pH rather than molecular CO 2 , and that pH i reflects a dynamic interaction of intracellular CO 2 hydration/dehydration, buffering, and transmembrane acid/base exchange. We used the Na + /H + exchange (NHE) blocker dimethyl amiloride (DMA) to test NHE’s role in single‐unit IPC response to combined phasic and tonic CO 2 step stimuli in anesthetized mallards (n=9) . DMA depressed mean (tonic) IPC discharge response to CO 2 step stimuli by 15%, 31%, 51%, and 58% at 1,3,8, and 13 µmol/kg, (p<0.05), but did not affect phasic discharge (spike frequency adaptation index, SFA). Depression of tonic CO 2 response confirms earlier reports, and the new result that NHE has no effect on the phasic part of IPC step response demonstrates that other mechanisms must underlie SFA. Grant Funding Source : Supported by: NIH R15 HL087269‐02 and R25 GM056931‐15.