Contribution of proton transporter to acid-induced receptor potential in frog taste cells.

1. The generative mechanism of the acid-induced receptor potential in frog taste cells was re-examined with micro-electrodes. 2. The amplitude of receptor potentials in a taste cell induced by 1 mM acetic acid increased as the concentration of Ca2+, Sr2+ and Ba2+ on the tongue surface was increased. 3. The amplitude of the acid-induced receptor potential was inhibited by about 40% by a proton pump blocker DCCD (N,N'-dicyclohexylcarbodiimide) added to superficial normal saline. 4. It is concluded that most of the acid-induced response in a frog taste cell was generated by current carried through proton-gated Ca2+ channel of the apical receptive membrane. The remaining part of the acid response was generated by current carried through a DCCD-sensitive proton transporter of the receptive membrane.