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X. W. Fu, C. A. Nurse, E. Cutz
Expression of functional purinergic receptors in pulmonary neuroepithelial bodies and their role in hypoxia chemotransmission
Adenine nucleotides act through specific cell surface receptors to invoke a variety of biological responses. Here we show that cells of neuroepithelial bodies (NEB), presumed O2 airway sensors in neonatal hamster lung, express functional P2X receptors (P2XR). Positive immunostaining was detected in NEB cells using doublelabel immunohistochemistry with antibodies against P2X2 and P2X3 receptor subunits, which colocalized with serotonin (5-HT), a marker of NEB cells. For electrophysiological characterization of P2X2-R in NEB cells, fresh neonatal hamster lung slice preparation was used. Under wholecell patch clamp, perfusion with ATP induced a concentrationdependent, nondesensitizing inward current (EC50=12 uM). Perfusion with ?, ?-methylene ATP also induced a slowdesensitizing inward current (EC50=8.2 uM). Suramin (IC50 ca. 43 M) and TNPATP (IC50 ca. 8 uM) blocked the currents evoked by both ATP and ?, ?methylene ATP. Using carbon fiber amperometry we observed that hypoxia and ATP induced 5-HT release from NEB cells and that this release was blocked by suramin. These data suggest that functional P2X2/3 heteromeric receptors are expressed in NEB cells. The possible function of these purinoreceptors in NEB cells could include modulation of hypoxia chemotransmission.
Biological Chemistry, Walter de Gruyter
Print ISSN: 1431-6730
Volume: 385, 04/2004
Pages: 275 - 284