Figure 4. Effects of lactate on acid-induced currents in AVP-eGFP neurons.

A, lactate enhances acid-gated currents in a concentration-dependent manner and does not directly activate ASICs. Currents induced by a change to pH 6.3 increased with lactate concentration and showed no saturation up to 30 mm. B, proton dose response of the currents in the presence or absence of 15 mm lactate. C, lactate enhanced the current only if it was applied with the stimulating solution and 30 s preincubation had no additional effect. The ratio of ‘b’ to ‘a’ is 1.03 ± 0.03, and that of ‘d’ to ‘c’ is 0.99 ± 0.03 (P > 0.05 compared with each basal, n= 4).