Sodium is the main cation in the extracellular fluid and it regulates various physiological functions. Depletion of sodium in the body increases the hedonic value of sodium taste, which drives animals towards sodium consumption1,2. By contrast, oral sodium detection rapidly quenches sodium appetite3,4, suggesting that taste signals have a central role in sodium appetite and its satiation. Nevertheless, the neural mechanisms of chemosensory-based appetite regulation remain poorly understood. Here we identify genetically defined neural circuits in mice that control sodium intake by integrating chemosensory and internal depletion signals. We show that a subset of excitatory neurons in the pre-locus coeruleus express prodynorphin, and that these neurons are a critical neural substrate for sodium-intake behaviour. Acute stimulation of this population triggered robust ingestion of sodium even from rock salt, while evoking aversive signals. Inhibition of the same neurons reduced sodium consumption selectively. We further demonstrate that the oral detection of sodium rapidly suppresses these sodium-appetite neurons. Simultaneous in vivo optical recording and gastric infusion revealed that sodium taste—but not sodium ingestion per se—is required for the acute modulation of neurons in the pre-locus coeruleus that express prodynorphin, and for satiation of sodium appetite. Moreover, retrograde-virus tracing showed that sensory modulation is in part mediated by specific GABA (γ-aminobutyric acid)-producing neurons in the bed nucleus of the stria terminalis. This inhibitory neural population is activated by sodium ingestion, and sends rapid inhibitory signals to sodium-appetite neurons. Together, this study reveals a neural architecture that integrates chemosensory signals and the internal need to maintain sodium balance.
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Geerling, J. C. & Loewy, A. D. Central regulation of sodium appetite. Exp. Physiol. 93, 177–209 (2008).
Johnson, A. K. & Thunhorst, R. L. The neuroendocrinology of thirst and salt appetite: visceral sensory signals and mechanisms of central integration. Front. Neuroendocrinol. 18, 292–353 (1997).
Nachman, M. & Valentino, D. A. Roles of taste and post-ingestional factors in the satiation of sodium appetite in rats. J. Comp. Physiol. Psychol. 62, 280–283 (1966).
Wolf, G., Schulkin, J. & Simson, P. E. Multiple factors in the satiation of salt appetite. Behav. Neurosci. 98, 661–673 (1984).
Augustine, V., Gokce, S. K. & Oka, Y. Peripheral and central nutrient sensing underlying appetite regulation. Trends Neurosci. 41, 526–539 (2018).
Faraco, G. et al. Dietary salt promotes neurovascular and cognitive dysfunction through a gut-initiated TH17 response. Nat. Neurosci. 21, 240–249 (2018).
Milan, A., Mulatero, P., Rabbia, F. & Veglio, F. Salt intake and hypertension therapy. J. Nephrol. 15, 1–6 (2002).
Oka, Y., Ye, M. & Zuker, C. S. Thirst driving and suppressing signals encoded by distinct neural populations in the brain. Nature 520, 349–352 (2015).
Rowland, N. E. & Fregly, M. J. Sodium appetite: species and strain differences and role of renin-angiotensin-aldosterone system. Appetite 11, 143–178 (1988).
Richter, C. P. Increased salt appetite in adrenalectomized rats. Am. J. Physiol. 115, 155–161 (1936).
Denton, D. A. & Sabine, J. R. The selective appetite for Na+ shown by Na+-deficient sheep. J. Physiol. (Lond.) 157, 97–116 (1961).
Dicara, L. V. & Wilson, L. M. Role of gustation in sodium appetite. Physiol. Psychol. 2, 43–44 (1974).
Sakai, R. R., Nicolaïdis, S. & Epstein, A. N. Salt appetite is suppressed by interference with angiotensin II and aldosterone. Am. J. Physiol. 251, R762–R768 (1986).
Jarvie, B. C. & Palmiter, R. D. HSD2 neurons in the hindbrain drive sodium appetite. Nat. Neurosci. 20, 167–169 (2017).
Matsuda, T. et al. Distinct neural mechanisms for the control of thirst and salt appetite in the subfornical organ. Nat. Neurosci. 20, 230–241 (2017).
Resch, J. M. et al. Aldosterone-sensing neurons in the NTS exhibit state-dependent pacemaker activity and drive sodium appetite via synergy with angiotensin II signaling. Neuron 96, 190–206 (2017).
Stein, M. K. & Loewy, A. D. Area postrema projects to FoxP2 neurons of the pre-locus coeruleus and parabrachial nuclei: brainstem sites implicated in sodium appetite regulation. Brain Res. 1359, 116–127 (2010).
Hull, C. L. Principles of Behavior: An Introduction to Behavior Theory (Appleton-Century, Oxford, 1943).
Augustine, V. et al. Hierarchical neural architecture underlying thirst regulation. Nature 555, 204–209 (2018).
Betley, J. N. et al. Neurons for hunger and thirst transmit a negative-valence teaching signal. Nature 521, 180–185 (2015).
Chen, Y., Lin, Y. C., Kuo, T. W. & Knight, Z. A. Sensory detection of food rapidly modulates arcuate feeding circuits. Cell 160, 829–841 (2015).
Zimmerman, C. A. et al. Thirst neurons anticipate the homeostatic consequences of eating and drinking. Nature 537, 680–684 (2016).
Chandrashekar, J. et al. The cells and peripheral representation of sodium taste in mice. Nature 464, 297–301 (2010).
Heck, G. L., Mierson, S. & DeSimone, J. A. Salt taste transduction occurs through an amiloride-sensitive sodium transport pathway. Science 223, 403–405 (1984).
Geerling, J. C. & Loewy, A. D. Aldosterone-sensitive neurons in the nucleus of the solitary tract: efferent projections. J. Comp. Neurol. 497, 223–250 (2006).
Zardetto-Smith, A. M., Beltz, T. G. & Johnson, A. K. Role of the central nucleus of the amygdala and bed nucleus of the stria terminalis in experimentally-induced salt appetite. Brain Res. 645, 123–134 (1994).
Smith, C. M. & Lawrence, A. J. Salt appetite, and the influence of opioids. Neurochem. Res. 43, 12–18 (2018).
Sternson, S. M. & Eiselt, A. K. Three pillars for the neural control of appetite. Annu. Rev. Physiol. 79, 401–423 (2017).
Beutler, L. R. et al. Dynamics of gut-brain communication underlying hunger. Neuron 96, 461–475 (2017).
Su, Z., Alhadeff, A. L. & Betley, J. N. Nutritive, post-ingestive signals are the primary regulators of AgRP neuron activity. Cell Rep. 21, 2724–2736 (2017).
Paxinos, G. & Franklin, K. B. The Mouse Brain in Stereotaxic Coordinates 2nd edn (Academic, London, UK, 2001).
Sadio, A. et al. A mouse intra-intestinal infusion model and its application to the study of nanoparticle distribution. Front. Physiol. 7, 579 (2016).
Ueno, A. et al. Mouse intragastric infusion (iG) model. Nat. Protocols 7, 771–781 (2012).
Berndt, A. et al. Structural foundations of optogenetics: determinants of channelrhodopsin ion selectivity. Proc. Natl Acad. Sci. USA 113, 822–829 (2016).
Roth, B. L. DREADDs for neuroscientists. Neuron 89, 683–694 (2016).
Oka, Y., Butnaru, M., von Buchholtz, L., Ryba, N. J. & Zuker, C. S. High salt recruits aversive taste pathways. Nature 494, 472–475 (2013).
Peng, Y. et al. Sweet and bitter taste in the brain of awake behaving animals. Nature 527, 512–515 (2015).
Allen, W. E. et al. Thirst-associated preoptic neurons encode an aversive motivational drive. Science 357, 1149–1155 (2017).
Leib, D. E. et al. The forebrain thirst circuit drives drinking through negative reinforcement. Neuron 96, 1272–1281.e4 (2017).
Lerner, T. N. et al. Intact-brain analyses reveal distinct information carried by SNc dopamine subcircuits. Cell 162, 635–647 (2015).
Callaway, E. M. & Luo, L. Monosynaptic circuit tracing with glycoprotein-deleted rabies viruses. J. Neurosci. 35, 8979–8985 (2015).
Petreanu, L., Huber, D., Sobczyk, A. & Svoboda, K. Channelrhodopsin-2-assisted circuit mapping of long-range callosal projections. Nat. Neurosci. 10, 663–668 (2007).
Geerling, J. C. & Loewy, A. D. Sodium deprivation and salt intake activate separate neuronal subpopulations in the nucleus of the solitary tract and the parabrachial complex. J. Comp. Neurol. 504, 379–403 (2007).
Geerling, J. C. et al. FoxP2 expression defines dorsolateral pontine neurons activated by sodium deprivation. Brain Res. 1375, 19–27 (2011).
Hurley, S. W. & Johnson, A. K. The biopsychology of salt hunger and sodium deficiency. Pflugers Arch. Eur. J. Physiol. 467, 445–456 (2015).
Stuber, G. D. & Wise, R. A. Lateral hypothalamic circuits for feeding and reward. Nat. Neurosci. 19, 198–205 (2016).
Andermann, M. L. & Lowell, B. B. Toward a wiring diagram understanding of appetite control. Neuron 95, 757–778 (2017).
Tye, K. M. Neural circuit motifs in valence processing. Neuron 100, 436–452 (2018).
We thank the members of the Oka laboratory and D. J. Anderson for discussion and comments; B. Lowell and M. Krashes for providing PDYN–Cre mice; A. Fejes-Toth for HSD2–Cre mice; and Y. Peng for real-time mouse tracking software. This work was supported by Startup funds from California Institute of Technology. Y.O. is supported by the Searle Scholars Program, the Mallinckrodt Foundation, the McKnight Foundation, the Klingenstein-Simons Foundation, and the National Institutes of Health (NIH) (R56MH113030, R01NS109997). D.K. is supported by the NIH (R01 DK108797 and R01 NS107315). H.E. is supported by the Japan Society for the Promotion of Science.
Nature thanks Charles Bourque, Ivan de Araujo and Michael McKinley for their contribution to the peer review of this work.
Extended data figures and tables
Extended Data Fig. 1 Behavioural paradigms for sodium-appetite induction and histological analysis of the pre-LC.
a, Experimental protocols for inducing thirst and sodium appetite. Intraperitoneal injection of furosemide (FURO) (50 mg per kg body weight) was used to induce sodium appetite. b, Sodium-depleted animals showed a strong preference for sodium whereas water-deprived animals preferred water over sodium (n = 9). c, Water-deprivation for 48 h induced robust c-FOS expression in the subfornical organ. However, it did not activate the pre-LC (representative image for one out of four mice that were tested). d, FISH showing that PDYN–Cre expression (visualized in the Ai3 transgenic line, green) overlaps with endogenous PDYN transcripts in the pre-LC (red, one out of two mice). e, Pre-LCPDYN neurons also overlap with FOXP2 expression, which is a known marker in the pre-LC43,44 (93.8 ± 1.1% (mean ±s.e.m.); n = 3). Scale bars, 50 μm. **P < 0.01 by two-tailed Wilcoxon test. Data are mean ± s.e.m.
a, Photostimulation of pre-LCPDYN neurons increased the intake of a lower concentration of NaCl (0.06 M and 0.15 M, n = 5 for eYFP, n = 4 for ChR2). b, Photostimulation triggered sodium appetite in both sexes (left, n = 7 female, n = 4 male), at any time of the day (right, n = 7). Data were partially reanalysed from Fig. 1e and g. c, Left, pre-LCPDYN-stimulated animals favoured NaCl over KCl (n = 9). Right, NaCl consumption was reduced in the presence of amiloride (n = 8). 0.5 M solutions were used for NaCl and KCl. d, Left, representative plots showing lick events during the 5 s of water or KCl access. Right, the effect of amiloride on water and KCl intake was quantified under water deprivation and sodium depletion. The total number of licks from five trials with amiloride was averaged and divided by that without amiloride (n = 9). *P < 0.05, **P < 0.01, ***P < 0.001 by two-tailed Mann–Whitney U-test or Friedman test (with Dunn’s multiple comparison). Data are mean ± s.e.m.
a, Electrophysiological recording in fresh brain slices. Illumination with 473-nm light strongly suppressed firing of pre-LCPDYN neurons expressing iC++ (10 out of 10 neurons from two mice). b, Representative image of AAV-DIO-iC++-eYFP expression in the pre-LC of a PDYN–Cre animal (one out of seven mice). c, Suppression of pre-LCPDYN neurons did not affect water intake in water-deprived animals (n = 5). d, AAV-DIO-eYFP controls for optogenetic inhibition (n = 5). e, AAV-DIO-hM4Di(Gi)-mCherry was bilaterally injected into the pre-LC. Representative recording demonstrates chemogenetic inhibition of pre-LCPDYN neurons by CNO (13 out of 14 neurons from two mice). f, Representative image of AAV-DIO-hM4Di(Gi)-mCherry expression in the pre-LC (one out of nine mice). g, Chemogenetic inhibition of pre-LCPDYN neurons reduced sodium intake in sodium-depleted animals. The same manipulation did not affect thirst (n = 9). h, CNO administration did not affect thirst or sodium appetite in animals that were injected with AAV-DIO-mCherry (n = 7). Scale bars, 50 μm. **P < 0.01 by two-tailed Wilcoxon test. Data are mean ± s.e.m.
a, A diagram of the training paradigm using foot shock (FS). Each lever press pauses continuous foot shock for 20 s. b, Total number of lever presses in each condition during the 30-min session (n = 5 for eYFP and n = 6 for ChR2). c, Animals were conditioned to press the lever without foot-shock pre-training sessions (n = 6). *P < 0.05 by two-tailed Wilcoxon test. Data are mean ± s.e.m.
a, Placement of an implanted optic fibre and GCaMP6s expression in the pre-LC. Scale bar, 50 μm. b, A low concentration (0.06 M) of NaCl had inhibitory effects on pre-LCPDYN neurons (n = 7). c, Licking an empty spout had no inhibitory effect on pre-LCPDYN neurons (n = 4 for eYFP, n = 4 for GCaMP6s). d, Peristimulus time histogram of GCaMP signals around the start of sodium ingestion. Data were magnified from c and Fig. 3a. Fluorescence changes (ΔF/F) from −1 to 0 s were calculated. e, Activity change per lick was quantified for Fig. 3d and e. *P < 0.05, **P < 0.01 by two-tailed Wilcoxon or two-tailed Mann–Whitney U-test. Data are mean ± s.e.m.
a, Functional validation of PDYN–GFP transgenic animals. Similar to the PDYN–Cre line, GFP-positive neurons in the pre-LC were activated by sodium depletion in PDYN–GFP mice (one out of two mice). b, A diagram of optogenetic stimulation of NTSHSD2 neurons. FOXP2-positive pre-LC neurons express c-FOS after HSD2 stimulation (n = 6 hemispheres from 3 mice). c, Relationship between the number of NTSHSD2 neurons in the NTS and c-FOS-positive neurons in the pre-LC. More than 95% of c-FOS-positive neurons expressed FOXP2. d, The number of FOXP2-positive neurons was not affected by the ablation of NTSHSD2 neurons (n = 18 hemispheres from 9 mice for +CASP3, and n = 8 hemispheres from 4 mice for –CASP3). Scale bars, 50 μm. **P < 0.01 by two-tailed Wilcoxon test. Data are mean ± s.e.m.
Extended Data Fig. 7 Histological analysis of putative upstream brain structures of pre-LCPDYN neurons.
a, Control monosynaptic tracing experiments without rabies glycoprotein (one out of three mice). Scale bars, 100 μm. b, Most PDYN neurons in the dBNST (green) are inhibitory neurons (red, 77.3 ± 1.7% (mean ± s.e.m.); n = 3). c, CAV2-positive neurons in the dBNST, labelled in a retrograde manner from the pre-LC (red), are inhibitory neurons (one out of three mice). Scale bars, 50 μm.
a, PDYN–Cre mice were injected with AAV-DIO-ChR2-mCherry into the pre-LC. Representative axonal projections are shown (one out of six mice). ARC, arcuate nucleus; DMH, dorsomedial hypothalamic nucleus; LH, lateral hypothalamus; PVT, paraventricular thalamic nucleus; vBNST, ventral bed nucleus of the stria terminalis; VTA, ventral tegmental area. Scale bars, 50 μm. b, A wiring diagram of upstream and downstream neural connections of pre-LCPDYN neurons. It is feasible that the ventral tegmental area and lateral hypothalamus process the reward aspect of sodium appetite45,46, whereas the BNST and paraventricular thalamic nucleus may regulate preference and valence towards sodium47,48. Besides the hindbrain, the BNST also receives interoceptive information from subfornical neurons that express angiotensin receptor (SFOAgtr1a)15.