2022 - Automated patch clamp screening of amiloride and 5-N,N-hexamethyleneamiloride (HMA) analogs identifies 6-iodoamiloride as a potent acid-sensing ion channel inhibitor
SyncroPatch 384PE (a predecessor model of the SyncroPatch 384 instrument) Patchliner Pre-Print Publication in bioRxiv (2022)
Finol-Urdaneta R.K., McArthur J.R., Aboelela A., Bujaroski R.S., Majed H., Rangel A., Adams D.J., Ranson M., Kelso M.J., Buckley B.J.
bioRxiv (2022) doi:10.1101/2022.03.12.484055
Acid-sensing ion channels (ASICs) are transmembrane sensors of extracellular acidosis and potential drug targets in several disease indications, including neuropathic pain and cancer metastasis. The K+-sparing diuretic amiloride is a moderate non-specific inhibitor of ASICs and has been widely used as a probe for elucidating ASIC function. In this work, we screened a library of 6-substituted and 5,6-disubstituted amiloride analogs using a custom-developed automated patch-clamp protocol and identified 6-iodoamiloride as a more potent ASIC1 inhibitor. Follow-up IC50 determinations in tsA-201 cells confirmed higher ASIC1 inhibitory potency for 6-iodoamiloride 97 (hASIC1 97 IC50 88 nM cf. amiloride 11 IC50 1.7 μM). A similar improvement in activity was observed in ASIC3-mediated currents from rat small diameter dorsal root ganglion neurons (rDRG single-concentration 97 IC50 230 nM cf. 11 IC50 2.7 μM). 6-iodoamiloride represents the amiloride analogue of choice for studying the effects of ASIC inhibition on cell physiology.