Gastric pH measurementsUsing non-se

Gastric pH measurements

Using non-selective electrodes we could demonstrate that no potential exists between the stomach lumen and the bath solution (Fig. S2 A). In contrast H+-selective electrodes recorded a negative potential of approximately 100 mV between gastric lumen a bath solution (Fig 2S B). Acute changes (up to 20 min) of the bath solution pH could not affect the gastric pH (Fig. S2 C). We additionally tested the effects of starvation on gastric pH homeostasis demonstrating decreased gastric pH in starved animals (Fig. S3). As the maintenance of high proton gradients between stomach lumen and the environment can be considered energetically expensive, decreased gastric pH can be considered an energy saving mode in response to starvation.