Extracellular protons activate K+ current in a subpopulation of frog taste receptor cells.

Based on morphological and electrophysiological criteria, two distinct subpopulations (group A and group B) taste receptor cells (TRCs) isolated from frog (Rana temporaria) taste disks were identified. TRCs from the group A were depolarized by acid stimuli which, in contrast, caused hyperpolarizing responses in group B TRCs. By using patch clamp technique we explored ion mechanisms mediating the pH dependent TRC hyperpolarization, and found that K+ conductance of TRCs from the group B increased as bath solution pH reduced. Our findings provide rationale to hypothesize that TRC from the group B express H+ gated K+ channels.