Neuronal nicotinic acetylcholine receptors (nAChRs) are Ca2+-permeable ligand-gated channels widely expressed in the central and peripheral nervous system. One of the most Ca2+ selective isoform is the homopentameric α7-nAChR implicated in schizophrenia. The activity of α7-nAChRs is usually recorded electrophysiologically, which limits the amount of information obtained. Here, we used fluorescence imaging to record Ca2+ transients associated with activation of the α7-nAChR in neuroblastoma cells stably expressing human α7-nAChRs. Application of nicotine (50 μM) consistently evoked transient (30 s), stereotyped Ca2+ responses that were inhibited by the selective α7-nAChRs antagonists methyllycaconitine (MLA) and α-bungarotoxin, and greatly increased and prolonged by the allosteric modulator PNU-120596 (1μM). Unexpectedly, brief (1–5 s), repetitive Ca2+ transients of sub-micrometric dimension were observed in filopodia of cells expressing α7-nAChR. PNU-120596 increased the frequency and slowed the decay kinetics of these miniature Ca2+ elevations, which were insensitive to ryanodine, preserved during hyperpolarisation, and prevented by MLA, α-bungarotoxin, or Ca2+ removal. Global Ca2+ responses were also recorded in ganglion cells of embryo chicken retina during co-application of PNU-120596 and nicotine, together with whole-cell currents and brief current bursts. These data demonstrate that Ca2+ signals generated by α7-nAChRs can be recorded optically both in cell lines and in intact tissues. The possibility to image miniature Ca2+ signals enables to map the location of functional α7-nAChR channel clusters within cells and to analyze their single channel properties optically. Deciphering the rich pattern of intracellular Ca2+ signals generated by the activity of the α7-nAChRs will reveal the physiological role of these receptor-channels.
Gilbert, D., Lecchi, M.M., Arnaudeau, S., Bertrand, D., & Demaurex, N. (2008). Local and global calcium signals associated with the opening of neuronal alpha7 nicotinic acetylcholine receptors. CELL CALCIUM, 45(2), 198-207.
|Citazione:||Gilbert, D., Lecchi, M.M., Arnaudeau, S., Bertrand, D., & Demaurex, N. (2008). Local and global calcium signals associated with the opening of neuronal alpha7 nicotinic acetylcholine receptors. CELL CALCIUM, 45(2), 198-207.|
|Tipo:||Articolo in rivista - Articolo scientifico|
|Carattere della pubblicazione:||Scientifica|
|Titolo:||Local and global calcium signals associated with the opening of neuronal alpha7 nicotinic acetylcholine receptors|
|Autori:||Gilbert, D; Lecchi, MM; Arnaudeau, S; Bertrand, D; Demaurex, N|
|Data di pubblicazione:||2008|
|Digital Object Identifier (DOI):||http://dx.doi.org/10.1016/j.ceca.2008.10.003|
|Appare nelle tipologie:||01 - Articolo su rivista|