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pH‐sensitive K + current in glial cells of the retrotrapezoid nucleus (RTN)
Author(s) -
Mulkey D K,
Kreneisz O,
Sun Y,
Chen X,
Nishiyama A
Publication year - 2009
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.23.1_supplement.621.11
Subject(s) - depolarization , chemoreceptor , membrane potential , neuroscience , current clamp , patch clamp , neuroglia , biophysics , electrophysiology , voltage clamp , neuron , chemistry , biology , central nervous system , biochemistry , receptor
The RTN contains pH‐sensitive neurons that sense changes in arterial pH to dive breathing (i.e., chemoreceptor). RTN glial cells are also thought to contribute to chemoreception by an unknown mechanism. We hypothesize that select glial cells in the RTN are intrinsically pH sensitive. To test this we made whole cell voltage clamp recordings from glial cells in transverse brain slices (300 ìm) from rats (P7‐12). Glial cells were defined based on a membrane potential <‐75 mV and an inability to generate action potentials. We found a subset of RTN glial cells feature a pH‐sensitive current; alkalization increased outward current whereas acidification decreased outward current. The I‐V relationship of the pH‐sensitive current reveals a voltage‐independent current which reverses near EK (‐90 mV, N=14). Duel current clamp recordings from pH‐sensitive glial and RTN chemoreceptors identify an interaction between glia cells and neurons (cross correlation coefficient, 0.8); glial cell depolarization initiates neuronal depolarization with a delay of ~50 ms. These results indicate that i) RTN glial cells can respond to physiologically relevant changes in pH; ii) a voltage‐independent K + channel likely confers pH‐sensitivity to RTN glia; iii) pH‐sensitive glial cells can interact with RTN chemoreceptors. These results identify a potential mechanism by which RTN glial cells can contribute to central chemoreception.