Fig. 5: Depolarization and action potential firing induced by lactate in glomus cells.

a–c Representative examples of lactate (10 mM)-induced reversible depolarization in a current clamped cell (perforated patch) maintained at the spontaneous resting potential (RP ≈ 30-40 mV). c In cells hyperpolarized to ~ −70 mV by current injection (red line and arrow) lactate (10 mM) induced larger depolarizations and the firing of action potentials. b Box plots representing the amplitudes of lactate (10 mM)-induced depolarizations in the two conditions. Mean ± SEM values were: 9.5 ± 1 mV (n = 17 cells from 16 mice) at RP; 31.2 ± 4 mV (n = 16 cells from 10 mice) at ~ −70 mV. The boxplot represents the median (middle line), 25th, 75th percentile (box), and largest and smallest values extending no further than 1.5× interquartile range (whiskers). Source data are provided as a Source data file. d Cell hyperpolarization and abolition of the lactate (10 mM)-induced depolarization after replacement of extracellular Na⁺ with N-methyl-D-glucamine (NMDG). Similar results were obtained in all cells tested (7 cells from 4 mice). e Inhibition of lactate (10 mM)-induced depolarization and action potential firing by application of a short pulse of pyruvate (Pyr, 5 mM). Representative example of 8 cells recorded from 5 mice. Red line indicates current injection through the recording electrode to maintain a resting potential of ~ −70 mV. f Inhibition of lactate (10 mM)-induced depolarization and action potential firing by 2-APB (10 μM), a non-selective cation channel blocker. Representative example of 3 cells recorded from 3 mice. Red line indicates current injection through the recording electrode to maintain a resting potential of approximately −70 mV. Note that action potential amplitude is truncated due to the relatively long sampling interval (4 ms). g Reversible inhibition of the lactate (20 mM)-induced secretory response by 2-APB (10 μM). Representative example of 4 experiments in 3 mice.