Figure 3. Responses of orexin cells to glucose in the presence of different cytosolic concentrations of pyruvate and lactate.

A, representative membrane potential response of an orexin cell to 1→5 mm switch in glucose in the presence of 5 mm pipette pyruvate (typical response ofn = 4 cells).B, representative membrane potential response of an orexin cell to 1→5 mm switch in glucose in the presence of 20 mm pipette lactate (typical response ofn = 6 cells).C, dose–response of pyruvate or lactate-induced inhibition of the current (at –40 mV) induced by 1→5 mm switch in extracellular glucose (n = 4–7 cells per point, IC₅₀ values are 0.47 mm and 17.4 mm respectively, fit details are given in Methods).