Several members of the RFamide peptide family are known to have role in the regulation of feeding. For example, neuropeptide FF and prolactin-releasing peptide cause anorexigenic, while 26RFa and QRFP result in orexigenic effects in rodents. I.c.v. microinjection of neuropeptide RFRP-1 significantly reduced food and water intake in chicks. However, feeding related effects of RFRP-1 have not been studied in mammals yet. The central part of amygdala (CeA) is essentially involved in the regulation of feeding and body weight. RFRP-1 positive nerve cells were detected in the rat hypothalamus and RFRP-1 immunoreactive fibers were identified in the CeA. RFRP analogs bind with relatively high affinity to the NPFF1 and NPFF2 receptors (NPFF-R). RFRP-1 has potent activity for NPFF1. Significant expression of NPFF1 was detected in the CeA. To evaluate the role of RFRP-1 in feeding regulation rats were microinjected with different doses of RFRP-1 and their food intake were quantified over a 60. min period. Liquid food intake of male Wistar rats was measured after bilateral intraamygdaloid administration of RFRP-1 (25, 50 or 100. ng/side, RFRP-1 dissolved in 0.15. M sterile NaCl/0.4. μl, respectively). The 50. ng dose of RFRP-1 microinjections resulted in significant decrease of food intake. The 25 and 100. ng had no effect. Action of 50. ng (37.8. pmol) RFRP-1 was eliminated by 20. ng (41.4. pmol) RF9 NPFF-R antagonist pretreatment. In open-field test 50. ng RFRP-1 did not modify spontaneous locomotor activity and general behavior of animals did not change. Our results are the first reporting that RFRP-1 injected to the CeA result in a decrease of liquid food consumption. This is a receptor-linked effect because it was eliminated by a NPFF-R selective antagonist.
|Number of pages||7|
|Journal||Brain Research Bulletin|
|Publication status||Published - Sep 1 2012|
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