Chronic hypoxia remodels voltage-gated Ca2+ entry in a human airway chemoreceptor cell line.
Arterial and airway chemoreceptors respond to acute hypoxia by depolarizing, thereby activating voltage-gated Ca2+ channels and so permitting Ca2+ entry to trigger transmitter release. Following periods of prolonged hypoxia, these cells undergo a form of remodelling which involves altered expression of ion channels. Here, we use microspectrofluorimetric recordings of voltage-gated Ca2+ entry (activated by exposure of cells to 50 mM K+) to show that chronic hypoxia suppresses such Ca2+ entry in model airway chemoreceptor (H146) cells. Furthermore, Ca2+ entry via L-type channels is suppressed, whilst entry via N-type channels is greatly enhanced. The suppressed response, together with dramatic remodelling of routes available for voltage-gated Ca2+ entry, is likely to alter significantly the acute O2 sensing properties of these cells.
Colebrooke
R L
RL
Institute for Cardiovascular Research, University of Leeds, Leeds LS2 9JT, UK.
Smith
I F
IF
Kemp
P J
PJ
Peers
C
C
D002118:Calcium / Q000378:metabolism*; D002121:Calcium Channel Blockers / Q000494:pharmacology; D015220:Calcium Channels / Q000187:drug effects / Q000378:metabolism*; D020013:Calcium Signaling / Q000187:drug effects / Q000502:physiology*; D002628:Chemoreceptor Cells / Q000187:drug effects / Q000378:metabolism*; D002908:Chronic Disease; D006801:Humans; D000860:Hypoxia / Q000378:metabolism* / Q000503:physiopathology; D008564:Membrane Potentials / Q000187:drug effects / Q000502:physiology; D011188:Potassium / Q000494:pharmacology; D012137:Respiratory System / Q000187:drug effects / Q000378:metabolism*; D014407:Tumor Cells, Cultured
D002121:Calcium Channel Blockers; D015220:Calcium Channels; D011188:Potassium; D002118:Calcium