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. 2019 Aug 13;14(8):e0220937. doi: 10.1371/journal.pone.0220937

Fig 3. Glucose depletion decreases SBPM.

Fig 3

A) Cartoon schematic of substrate depletion-repletion experimental protocol described in Materials and Methods. Each wash-incubate-equilibrate-record epoch was performed using fresh media regardless of substrate composition. B) Synchronous burst frequency decreases following 10min incubation in the absence of extracellular glucose (25mM) and pyruvate (0.22mM), and significantly further still following a second 10min incubation. Replenishment of glucose alone is sufficient to restore a significantly higher SBPM. No substrate 20min versus glucose and pyruvate P = 0.013; no substrate 20min versus no substrate 10min P = 0.003; glucose alone versus no substrate 20min P = 0.012; N = 4. C) Only the metabolically active D-isoform of glucose (not L-glucose) can sustain a significantly higher SBPM in physiologically-relevant conditions containing 5mM D- or L-glucose, 5mM DL-lactate (racemic mixture) and 0.22mM pyruvate. L-glucose 20min versus D-glucose control P < 0.001; L-glucose 20min versus L-glucose 10min P = 0.027; D-glucose replenishment versus L-glucose 20min P = 0.014; N = 4.