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Can robots patch‐clamp as well as humans? Characterization of a novel sodium channel mutation
Author(s) -
Estacion M.,
Choi J. S.,
Eastman E. M.,
Lin Z.,
Li Y.,
Tyrrell L.,
Yang Y.,
DibHajj S. D.,
Waxman S. G.
Publication year - 2010
Publication title -
the journal of physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.802
H-Index - 240
eISSN - 1469-7793
pISSN - 0022-3751
DOI - 10.1113/jphysiol.2009.186114
Subject(s) - patch clamp , sodium channel , ion channel , mutant , biophysics , voltage clamp , clamp , electrophysiology , chemistry , computer science , membrane potential , sodium , biology , neuroscience , clamping , biochemistry , receptor , organic chemistry , gene , computer vision
Ion channel missense mutations cause disorders of excitability by changing channel biophysical properties. As an increasing number of new naturally occurring mutations have been identified, and the number of other mutations produced by molecular approaches such as in situ mutagenesis has increased, the need for functional analysis by patch‐clamp has become rate limiting. Here we compare a patch‐clamp robot using planar‐chip technology with human patch‐clamp in a functional assessment of a previously undescribed Na v 1.7 sodium channel mutation, S211P, which causes erythromelalgia. This robotic patch‐clamp device can increase throughput (the number of cells analysed per day) by 3‐ to 10‐fold. Both modes of analysis show that the mutation hyperpolarizes activation voltage dependence (−8 mV by manual profiling, −11 mV by robotic profiling), alters steady‐state fast inactivation so that it requires an additional Boltzmann function for a second fraction of total current (∼20% manual, ∼40% robotic), and enhances slow inactivation (hyperpolarizing shift −15 mV by human, −13 mV robotic). Manual patch‐clamping demonstrated slower deactivation and enhanced (∼2‐fold) ramp response for the mutant channel while robotic recording did not, possibly due to increased temperature and reduced signal‐to‐noise ratio on the robotic platform. If robotic profiling is used to screen ion channel mutations, we recommend that each measurement or protocol be validated by initial comparison to manual recording. With this caveat, we suggest that, if results are interpreted cautiously, robotic patch‐clamp can be used with supervision and subsequent confirmation from human physiologists to facilitate the initial profiling of a variety of electrophysiological parameters of ion channel mutations.