Appetite (hunger and satiety) is controlled by neural circuits in the brain – particularly in the hypothalamus – and their reciprocal connections to peripheral organs involved in energy metabolism (gut and liver). Understanding the structural organization of these circuits (their synaptic connections) and their neurochemistry (particularly which neurotransmitters are used at which synapses) is of fundamental importance for human health and developing new treatments for metabolic disorders such as obesity and diabetes. Neuroscientist Henning Fenselau at the Max Planck Institute and University of Cologne Germany has made several major discoveries about how food intake and energy metabolism are regulated and the consequences of abnormalities in the underlying neural circuits. Among his recent findings concern how GLP-1 in the gut communicates with the brain via the vagus nerve, and the roles of specific synaptic signals (NPY, opioids, TRH, and GABA).

LINKS

Fenselau laboratory page: https://www.sf.mpg.de/research/fenselau

GLP-1, the vagus nerve, hunger, and sugar metabolism:

https://www.cell.com/action/showPdf?pii=S1550-4131%2821%2900219-9

Synaptic amplifier of hunger:

https://pmc.ncbi.nlm.nih.gov/articles/PMC10160008/pdf/nihms-1882224.pdf

Opioids and sugar appetite

https://www-science-org.proxy1.library.jhu.edu/doi/epdf/10.1126/science.adp1510

Brainstem – amygdala circuit during fasting

https://pmc.ncbi.nlm.nih.gov/articles/PMC11211344/pdf/41467_2024_Article_49766.pdf

One of the most remarkable feats of biological ‘wizardry’ in the animal kingdom is the ability of some cephalopods (octopuses, squids, and cuttlefish) to rapidly change the color, patterning, and texture of their skin so as to blend in with their background. They accomplish these feats through the linking of neural circuits in the visual system and brain to muscle cells that control the dispersion of pigment in specialized skin cells called chromatophores. But the details of the neural circuitry and the computational processes that control the camouflaging process remain largely unknown. In this episode Columbia University neuroscientist Tessa Montague talks about her research on the neurobiology of camouflage and the many challenges that must be overcome to better understand this remarkable phenomenon.

LINKS

Dr. Montague’s cuttlefish lab webpage: Tessamontague.com

Links to camouflaging cephalopods

https://www.youtube.com/watch?v=XocHDvHlcJM

https://www.youtube.com/watch?v=Ojb1pxcSr5E

Articles on the neurobiology of camouflage

https://www.cell.com/action/showPdf?pii=S0960-9822%2823%2901182-X

https://www.sciencedirect.com/science/article/pii/S0959438824000382?via%3Dihub

https://www.cell.com/action/showPdf?pii=S0960-9822%2823%2900757-1

During vigorous exercise lactic acid (lactate) levels increase in the blood and during fasting and extended exercise the levels of the ketone BHB (b-hydroxybutyrate) increase. In this episode I talk with Stanford University professor Jonathan Long about his recent discovery that lactate and BHB in the blood are bound to the amino acid phenylalanine and that they (Lac-Phe and BHB-Phe) have beneficial effects on metabolic and brain health. Lac-Phe levels increase markedly in response to exercise in mice, humans, and race horses. Peripheral administration of Lac-Phe in suppresses food intake and reverses diet-induced obesity and insulin resistance in mice. Genetic ablation of Lac-Phe biosynthesis causes hyperphagy and obesity even in exercising mice showing a critical role for Lac-Phe in the beneficial effects of exercise. BHB-Phe has similar effects on food intake and metabolic health. We talk about the potential benefits of Lac-Phe and BHB-Phe for brain health and resilience.

LINKS

The Long laboratory webpage: https://longlabstanford.org/

Lac-Phe articles:

https://pmc.ncbi.nlm.nih.gov/articles/PMC9767481/pdf/nihms-1852727.pdf

https://pmc.ncbi.nlm.nih.gov/articles/PMC10635077/pdf/nihpp-2023.11.02.565321v1.pdf

BHB-Phe article: https://www.cell.com/action/showPdf?pii=S0092-8674%2824%2901214-5