Cell Imaging with Pharmacological Modulators

Most of the techniques used in this study have been described in detail elsewhere [7 (link)]. The bath solution for cell imaging consisted of (in mM) 140 NaCl, 5 KCl, 1.1 MgCl₂, 2.5 CaCl₂, 10 HEPES, with the pH adjusted to 7.2 with NaOH. N-methyl-d-glucamine was added to maintain the solutions’ osmolarity. Five mM glucose was always added to the bath solutions (with or without HK expression), so that HK would be active when present. Solutions were perfused directly over the cells using a gravity-fed eight-way perfusion device (Warner Instruments, Hamden, CT, USA) with electrically controlled solenoids (The Lee Company, Westbrook, CT, USA). Input and output of solution to the recording chamber (glass bottomed Petri dish) were equilibrated to maintain constant flow rates and volumes. Sodium Cyanide (NaCN) and 6-Aminonicotinamide (6-AN) were purchased from Sigma-Aldrich. The inhibitor of ME1 (ME1*) was purchased from (ProbeChem Biochemicals, Shanghai, China).