Ciuraszkiewicz_2013_J.Physiol_591_3271

Previous attempts to measure the functional properties of recombinant nicotinic acetylcholine receptors (nAChRs) composed of known receptor subunits have yielded conflicting results. The use of knockout mice that lack alpha5, beta2, alpha5beta2 or alpha5beta2alpha7 nAChR subunits enabled us to measure the single-channel properties of distinct alpha3beta4, alpha3beta4alpha5 and alpha3beta4beta2 receptors in superior cervical ganglion (SCG) neurons. Using this approach, we found that alpha3beta4 receptors had a principal conductance level of 32.6 +/- 0.8 pS (mean +/- SEM) and both higher and lower secondary conductance levels. alpha3beta4alpha5 receptors had the same conductance as alpha3beta4 receptors, but differed from alpha3beta4 receptors by having an increased channel open time and increased burst duration. By contrast, alpha3beta4beta2 receptors differed from alpha3beta4 and alpha3beta4alpha5 receptors by having a significantly smaller conductance level (13.6 +/- 0.5 pS). After dissecting the single-channel properties of these receptors using our knockout models, we then identified these properties - and hence the receptors themselves - in wild-type SCG neurons. This study is the first to identify the single-channel properties of distinct neuronal nicotinic receptors in their native environment.