A single injection of neuropeptide QRFP in the lateral hypothalamus decreased food intake.

Background and aim: Severe eating disorders, such as obesity, bulimia, and anorexia, keep increasing to epidemic proportions worldwide. Understanding of neuropeptides' role in complex hunger/satiety mechanisms may allow new prospects for treatment and prevention. Pyroglutamylated arginine-phenylalanine-amide peptides (QRFPs) are thought to enhance feeding following the central administration.

Methods: In our study, QRFP-26 was delivered into the lateral hypothalamic area of male Wistar rats by direct microinjections, as QRFP-26 expressing neurons and binding sights are densely present in this neural structure. The consumption of liquid food was measured over 60-min.

Results: Both doses (100 and 200 ng) significantly decreased food intake compared to the control treatment. Neuropeptide Y Y1R/NPFF (neuropeptide FF) antagonist BIBP3226 eliminated the anorexigenic effect caused by QRFP-26 administration. QRFP-26 affects neither general locomotion, behavioral patterns examined in the Open Field Test, nor anxiety.

Conclusion: This study is the first to report the anorexigenic action of QRFP-26 following direct administration into the hypothalamus, emphasizing steady locomotion and anxiety levels. We have shown that the effect of QRFP can be linked to the neuropeptide Y (NPY) Y1 or NPFF receptors.