Characterization of compounds on nicotinic acetylcholine receptor alpha7 channels using higher throughput electrophysiology
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Alpha7 nicotinic acetylcholine receptor channels are important ligand-gated ion channels that are fast desensitizing, cation selective and have been implicated in the pathophysiology of schizophrenia and Alzheimer’s disease. We report here high quality 7 parallel patch clamp recordings using the QPatch automated patch clamp system. The QPatch patch clamps up to 48 cells in parallel with the same high fidelity as conventional patch clamp. EC50 and IC50 values were comparable to values obtained with conventional patch clamp. The EC50 value for acetylcholine (ACh) on the QPatch with area under the curve (AUC) analysis was 26M compared to a value of 29M determined from conventional patch clamp experiments. Sequential additions of ACh can be made with minimal decay of the peak amplitude. The competitive7 antagonistmethyllycaconitine (MLA) blocked currents with an IC50 value of 0.25nM which is similar to published IC50 values for MLA. Finally, two different classes of positive allosteric modulators represented by PNU-120596 and NS-1738 elicited characteristic responses, thus allowing accurate characterization of modulation and measurements of potency. These results demonstrate that 7 nicotinic acetylcholine receptor channels can be studied reliably in a higher throughput, parallel manner with the QPatch automated patch clamp system.