In:
The Journal of Physiology, Wiley, Vol. 571, No. 3 ( 2006-03), p. 503-517
Abstract:
Airway ciliated cells express an ATP‐gated P2X receptor channel of unknown subunit composition (P2X cilia ) which is modulated by Na + and by long exposures to ATP. P2X cilia was investigated by recording currents from freshly dissociated rabbit airway ciliated cells with the patch‐clamp technique in the whole‐cell configuration. During the initial continuous exposure to extracellular ATP, P2X cilia currents gradually increase in magnitude (priming), yet the permeability to N ‐methyl‐ d ‐glucamine (NMDG) does not change, indicating that priming does not arise from a progressive change in pore diameter. Na + , which readily permeates P2X cilia receptor channels, was found to inhibit the channel extracellular to the electric field. The rank order of permeability to various monovalent cations is: Li + , Na + , K + , Rb + , Cs + , NMDG + and TEA + , with a relative permeability of 1.35, 1.0, 0.99, 0.91, 0.79, 0.19 and 0.10, respectively. The rank order for the alkali cations follows an Eisenman series XI for a high‐strength field site. Ca 2+ has been estimated to be 7‐fold more permeant than Na + . The rise in [Ca 2+ ] i in ciliated cells, induced by the activation of P2X cilia , is largely inhibited by either Brilliant Blue G or KN‐62, indicating that P2X 7 may be a part of P2X cilia . P2X cilia is augmented by Zn 2+ and by ivermectin, and P2X 4 receptor protein is detected by immunolabelling at the basal half of the cilia, strongly suggesting that P2X 4 is a component of P2X cilia receptor channels. Taken together, these results suggest that P2X cilia is either assembled from P2X 4 and P2X 7 subunits, or formed from modified P2X 4 subunits.
Type of Medium:
Online Resource
ISSN:
0022-3751
,
1469-7793
DOI:
10.1113/jphysiol.2005.103408
Language:
English
Publisher:
Wiley
Publication Date:
2006
detail.hit.zdb_id:
1475290-6
SSG:
12
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