AIMTo investigate the action and mechanism of Syn-1A in reversing the activation of K(ATP) channel induced by weak acidic pH.

METHODSThe patches excised from Kir6.2/SUR2A expressing HEK-293 cells were used to establish inside-out configuration. To examine the actions of weak acidic pH in activation of the channel and the reverse action of Syn-1A on it, the inside-out patches were continuously perfused with the solution of pH from 7.4, 7.0, 6.8, 6.5 to 6.0 with or without Syn-1A. In vitro binding was employed to study the influence of different pH to the binding of Syn-1A to SUR2A subunit.

RESULTSSyn-1A blocked pH 6.5, 6.8 and 7.0 induced activation of the channel, and Syn-1A binding to SUR2A were increased by reducing pH from 7.4 to 6.0.

CONCLUSIONSyn-1A would assert some inhibition of the KATP channels, which might temper the fluctuation of acidic pH-induced K(ATP) channel opening that could induce fatal re-entrant arrhythmias.