Pii: S0304-3940(01)02479-x

Arterial and airway chemoreceptors respond to acute hypoxia by depolarizing, thereby activating voltage-gated Ca channels and so permitting Ca 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 Ca entry (activated by exposure of cells to 50 mM K) to show that chronic hypoxia suppresses such Ca entry in model airway chemoreceptor (H146) cells. Furthermore, Ca 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 Ca entry, is likely to alter significantly the acute O2 sensing properties of these cells. q 2002 Elsevier Science Ireland Ltd. All rights reserved.