Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2014 Feb;39(3):605-13.
doi: 10.1038/npp.2013.235. Epub 2013 Sep 4.

Leptin signaling in the medial nucleus tractus solitarius reduces food seeking and willingness to work for food

Affiliations

Leptin signaling in the medial nucleus tractus solitarius reduces food seeking and willingness to work for food

Scott E Kanoski et al. Neuropsychopharmacology. 2014 Feb.

Abstract

The adipose-derived hormone leptin signals in the medial nucleus tractus solitarius (mNTS) to suppress food intake, in part, by amplifying within-meal gastrointestinal (GI) satiation signals. Here we show that mNTS leptin receptor (LepRb) signaling also reduces appetitive and motivational aspects of feeding, and that these effects can depend on energy status. Using the lowest dose that significantly suppressed 3-h cumulative food intake, unilateral leptin (0.3 μg) administration to the mNTS (3 h before testing) reduced operant lever pressing for sucrose under increasing work demands (progressive ratio reinforcement schedule) regardless of whether animals were energy deplete (food restricted) or replete (ad libitum fed). However, in a separate test of food-motivated responding in which there was no opportunity to consume food (conditioned place preference (CPP) for an environment previously associated with a palatable food reward), mNTS leptin administration suppressed food-seeking behavior only in chronically food-restricted rats. On the other hand, mNTS LepRb signaling did not reduce CPP expression for morphine reinforcement regardless of energy status, suggesting that mNTS leptin signaling differentially influences motivated responding for food vs opioid reward. Overall results show that mNTS LepRb signaling reduces food intake and appetitive food-motivated responding independent of energy status in situations involving orosensory and postingestive contact with food, whereas food-seeking behavior independent of food consumption is only reduced by mNTS LepRb activation in a state of energy deficit. These findings reveal a novel appetitive role for LepRb signaling in the mNTS, a brain region traditionally linked with processing of meal-related GI satiation signals.

PubMed Disclaimer

Figures

Figure 1
Figure 1
Representative mNTS injection site.
Figure 2
Figure 2
Cumulative home cage food intake in non-restricted rats following mNTS leptin administration (means±SEM; *indicates P-value<0.01).
Figure 3
Figure 3
Operant lever pressing for sucrose in a progressive ratio reinforcement test for both food-restricted and non-restricted rats, shown as: (a) the number of reinforcers (45 mg sucrose pellets) earned before reaching breakpoint criterion, and (b) the number of active lever presses performed before reaching breakpoint criterion (means±SEM; *indicates P-value<0.01).
Figure 4
Figure 4
Conditioned place preference expression for an environment previously associated with consuming palatable food (high fat and high sucrose) for both food-restricted and non-restricted rats (means±SEM; *indicates P-value<0.01).
Figure 5
Figure 5
Conditioned place preference expression for a location previously associated with morphine reinforcement for both food-restricted and non-restricted rats (means±SEM).

References

    1. Ahima RS, Saper CB, Flier JS, Elmquist JK. Leptin regulation of neuroendocrine systems. Front Neuroendocrinol. 2000;21:263–307. - PubMed
    1. Alhadeff AL, Rupprecht LE, Hayes MR. GLP-1 Neurons in the nucleus of the solitary tract project directly to the ventral tegmental area and nucleus accumbens to control for food intake. Endocrinology. 2012;153:647–658. - PMC - PubMed
    1. Appleyard SM, Bailey TW, Doyle MW, Jin YH, Smart JL, Low MJ, et al. Proopiomelanocortin neurons in nucleus tractus solitarius are activated by visceral afferents: regulation by cholecystokinin and opioids. J Neurosci. 2005;25:3578–3585. - PMC - PubMed
    1. Baldo BA, Kelley AE. Discrete neurochemical coding of distinguishable motivational processes: insights from nucleus accumbens control of feeding. Psychopharmacology (Berl) 2007;191:439–459. - PubMed
    1. Baldo BA, Pratt WE, Will MJ, Hanlon EC, Bakshi VP, Cador M.2013Principles of motivation revealed by the diverse functions of neuropharmacological and neuroanatomical substrates underlying feeding behavior Neurosci Biobehav Rev(e-pub ahead of print). - PMC - PubMed

Publication types

MeSH terms

LinkOut - more resources