TRPM4 mediates a subthreshold membrane potential oscillation in respiratory chemoreceptor neurons that drives pacemaker firing and breathing.
Cell Rep
; 34(5): 108714, 2021 02 02.
Article
en En
| MEDLINE
| ID: mdl-33535052
ABSTRACT
Brainstem networks that control regular tidal breathing depend on excitatory drive, including from tonically active, CO2/H+-sensitive neurons of the retrotrapezoid nucleus (RTN). Here, we examine intrinsic ionic mechanisms underlying the metronomic firing activity characteristic of RTN neurons. In mouse brainstem slices, large-amplitude membrane potential oscillations are evident in synaptically isolated RTN neurons after blocking action potentials. The voltage-dependent oscillations are abolished by sodium replacement; blocking calcium channels (primarily L-type); chelating intracellular Ca2+; and inhibiting TRPM4, a Ca2+-dependent cationic channel. Likewise, oscillation voltage waveform currents are sensitive to calcium and TRPM4 channel blockers. Extracellular acidification and serotonin (5-HT) evoke membrane depolarization that augments TRPM4-dependent oscillatory activity and action potential discharge. Finally, inhibition of TRPM4 channels in the RTN of anesthetized mice reduces central respiratory output. These data implicate TRPM4 in a subthreshold oscillation that supports the pacemaker-like firing of RTN neurons required for basal, CO2-stimulated, and state-dependent breathing.
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Texto completo:
1
Bases de datos:
MEDLINE
Asunto principal:
Respiración
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Células Quimiorreceptoras
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Canales Catiónicos TRPM
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Potenciales de la Membrana
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Neuronas
Límite:
Animals
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Humans
Idioma:
En
Revista:
Cell Rep
Año:
2021
Tipo del documento:
Article
País de afiliación:
Estados Unidos