Extended Data Fig. 1: Gastrointestinal osmolarity influences drinking behaviour and biases salt preference.
From: A gut-to-brain signal of fluid osmolarity controls thirst satiation
a, b, Additional data related to Fig. 1b, c. a, Cumulative water or 300 mM NaCl intake after dehydration (n = 5 mice). b, Example of SFO neuron dynamics during drinking after dehydration. c, Ingestion of hypertonic fluids activates SFO neurons regardless of hydration state. Average SFO activity and drinking behaviour of hydrated mice given ad libitum access to isotonic (300 mM sucrose) or hypertonic (300 mM sucrose + 600 mM mannitol) sugar solutions of similar sweetness (n = 5 mice). d, Increases in gastrointestinal osmolarity bias salt and water preference. Left, preference in a two-bottle test after intragastric treatment with hypertonic (red; n = 8 mice) or isotonic (black; n = 9 mice) NaCl (two-way ANOVA, Holm–Šídák correction). Right, cumulative water (solid lines) and 300 mM NaCl (dashed lines) intakes in the same two-bottle test. e–g, Post-ingestive SFO neuron activity does not reflect the delayed consequences of taste or sensorimotor experience associated with an individual drinking bout. e, Mice initially do not distinguish between bottles that contain water and bottles that contain 300 mM NaCl in a three-bottle test after dehydration (n = 4 mice, linear regression, R2 = 0.3163, P = 0.0233). f, Example of SFO neuron dynamics during drinking from water (black) and 300 mM NaCl (blue, red) bottles after dehydration. g, Left, SFO neuron dynamics during individual water (42 bouts) or NaCl (71 bouts) drinking bouts in trials 1 and 2 of the three-bottle test. Right, average SFO activity after individual drinking bouts (n = 4 mice). In this experiment (e–g), gastrointestinal osmolarity quickly becomes hypertonic as the dehydrated mice alternate between drinking from water and NaCl bottles, such that SFO neuron activity rebounds even after water-drinking bouts; this suggests that the stabilization signal that either quenches or re-activates SFO neurons after ingestion reflects gastrointestinal osmolarity. Error bars represent mean ± s.e.m. Shaded areas in a, c–e, g represent mean ± s.e.m.; shaded areas in b represent individual licks; shaded area in the linear regression (right) in e represents 95% confidence interval for the line of best fit; shaded areas in f represent individual drinking bouts. **P < 0.01, ***P < 0.001.
