<prompt> Tetraethylammonium TEA is a blocker of the:Na channelsK channelsChloride channelsCa channels  <response>: Tetraethylammonium TEA ion is known to block the K channels. It is used sometimes to stop the K currents, in order to study the other ionic currents and their effects on membrane potential. Tetrodotoxin TTX and saxitoxin STX are the blockers of Na channels. Niflumic acid is Cl- channel blocker used in scientific research studies. 