Figure 5.

Glucose-induced excitation implies the catabolism of glucose in neurons. A, Excitatory effect of glucose on the spontaneous firing activity of identified sleep-active cells under synaptic uncoupling conditions (low Ca²⁺/high Mg²⁺) (n = 4). Data are presented as mean ± SEM. *p < 0.05, permutation test. B, Effect of the application of a nonmetabolizable glucose analog (2-DG) on the spontaneous firing activity of identified putative sleep-promoting and glucose-excited neurons (n = 4). Data are presented as mean ± SEM. *p < 0.05, permutation test: ns. C, Effect of the blockade of lactate transporters (4-CIN) and glucokinase inhibition (alloxan) on the glucose-induced increase in resting membrane potential of identified sleep-active neurons. Data are presented as mean ± SEM with group sizes for each condition. **p < 0.01, Mann–Whitney test: ns. D, Gel electrophoresis of scRT-PCR products of three characterized sleep-promoting cells expressing GK mRNAs, with the third neuron expressing GK and GLUT3 mRNAs. MW, Molecular weight (100 bp ladder).