Weekend Food: Flavor Science – QRFP – Food mixes with mood

QRFP: not only food but also mood


The hypothalamus is a brain region implicated in several vital functions such as feeding, thermoregulation, reproduction, stress and metabolic regulation. Dozens of hypothalamic neuropeptides have been shown to be involved in the regulation of food intake and body weight homeostasis. The extreme heterogeneity of these chemical signals and the complex sub-architecture of the hypothalamus participate in regulating homeostatic adaptations.
Information about the body’s energy store is gathered by the arcuate nucleus (Arc), a small hypothalamic nucleus, and then transmitted to second order neurons, including ones localized in the paraventricular nucleus (PVN) and others in the lateral hypothalamic area (LHA), to evoke hunger sensation and feeding behavior. Since the seminal study of Anand and Brubeck (1951), the LHA has been identified as the “feeding center of the brain”. However, the exact contribution of each hypothalamic nucleus remains poorly understood and far from fully explored.
QRFP, a recently identified hypothalamic neuropeptide, has emerged as an interesting chemical signal in the LHA and adjacent regions. What is the function of this novel peptide?
In a recent PLOS ONE article, Okamoto and colleagues from the Kanazawa University in Japan, decided to explore the functions of this neuropeptide. Here is what they found.
QRFP, feeding and energy homeostasis
To examine the physiological role of QRFP, the authors generated a transgenic mouse line (Qrfp-/-) by replacing the entire prepro-QRFP sequence with the enhanced green fluorescent protein (eGFP) gene. Interestingly, under standard diet the body weight of Qrfp-/- mice was significantly lower than that of wildtype littermates. This phenotype was also maintained when the mice were exposed to high-fat diet, a protocol known to induce obesity and metabolic disorders. These experiments strongly suggest that QRFP may play a critical role in influencing feeding behavior and central energy homeostasis.
Localization of QRFP in the mouse hypothalamus (Okamoto et al., 2016)
The two major neuronal populations that control food intake are the arcuate POMC and AgRP neurons. Taking advantage of the eGFP expression of QRFP-expressing LHA neurons, the authors observed that arcuate AgRP neurons were able to contact those cells, thus suggesting a synaptic link. Interestingly, “the area of distribution of AgRP fibers in the hypothalamus overlapped with that of QRFP-positive neurons”, say Kitaro Okamoto, the leading author of the study.
QRFP: not only food but also mood
Interestingly, most substances that affect food intake show effects on mood and motivation simultaneously, and eating disorders are (more above at the link)

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