Fig. 1.

Racemic lactate triggers ASIC1a dependent [Ca²⁺]_cand [Ca²⁺]_msignals.

(A) Illustration of the figure hypothesis;

(B) Representative Fura-2 ratio traces for [Ca²⁺]_c changes monitored in WT primary cultured hippocampal neurons (DIV 10–15) without and with pretreatment of the selective ASIC1a inhibitor PcTx1 (20 nM, 120 s). Neurons were loaded with Fura-2AM (1 μM) and initially superfused with Ringer's solution at pH 7.4. Then, the superfusion was switched to Ringer's solution of pH 7.4 with an addition of DL-lactate (5 mM) as indicated by the arrowhead;

(C) Quantification of the number of cytosolic (cyto) Ca²⁺ peaks (transients) per 180-s time period measured as in (B) for WT neurons untreated (n = 39) and treated (n = 77); Box and whiskers plot show maximal and minimal values and all data points;

(D) Representative Rhod-2 fluorescence traces for [Ca²⁺]_m changes in Rhod-2 AM (1 μM)-loaded WT neurons untreated and treated with PcTX1. Superfusion was switched to pH 7.4 Ringer's solution with DL-lactate;

(E) Quantification of peak [Ca²⁺]_m based on F/F₀ during the maximum phases as in (D) for WT neurons untreated (n = 11) and treated with PcTX1 (n = 65);

(F) Representative Rhod-2 fluorescence traces for [Ca²⁺]_m changes in response to direct puffing of the pH 7.4-DL- lactate solution in primary cultured WT and KO cortical neurons;

(G) Quantification of peak [Ca²⁺]_m based on F/F₀ during the maximum phases as in (F) for WT (n = 6) and KO cortical neurons (n = 5);

All summary data represent mean ± SD, ****p < 0.0001.