Institute of Physiology, Pécs University Medical School, Pécs, Hungary.
Brain Res Bull. 2012 Sep 1;88(6):589-95. doi: 10.1016/j.brainresbull.2012.06.001. Epub 2012 Jun 9.
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 60min period. Liquid food intake of male Wistar rats was measured after bilateral intraamygdaloid administration of RFRP-1 (25, 50 or 100ng/side, RFRP-1 dissolved in 0.15M sterile NaCl/0.4μl, respectively). The 50ng dose of RFRP-1 microinjections resulted in significant decrease of food intake. The 25 and 100ng had no effect. Action of 50ng (37.8pmol) RFRP-1 was eliminated by 20ng (41.4pmol) RF9 NPFF-R antagonist pretreatment. In open-field test 50ng 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.
几种 RFamide 肽家族成员已知在调节进食中起作用。例如，神经肽 FF 和催乳素释放肽导致厌食症，而 26RFa 和 QRFP 则在啮齿动物中产生食欲亢进的效果。下丘脑室旁核内微量注射神经肽 RFRP-1 可显著减少雏鸡的食物和水摄入量。然而，RFRP-1 对哺乳动物摄食的影响尚未得到研究。杏仁核中央区（CeA）在调节摄食和体重方面起着重要作用。在大鼠下丘脑检测到 RFRP-1 阳性神经细胞，并在 CeA 中鉴定出 RFRP-1 免疫反应纤维。RFRP 类似物与 NPFF1 和 NPFF2 受体（NPFF-R）具有相对较高的亲和力结合。RFRP-1 对 NPFF1 具有很强的活性。在 CeA 中检测到 NPFF1 的显著表达。为了评估 RFRP-1 在摄食调节中的作用，向大鼠脑室内注射不同剂量的 RFRP-1，并在 60 分钟内定量其食物摄入量。在双侧杏仁核内注射 RFRP-1（25、50 或 100ng/侧，RFRP-1 溶解在 0.15M 无菌 NaCl/0.4μl 中）后，测量雄性 Wistar 大鼠的液体食物摄入量。50ng 的 RFRP-1 微注射导致食物摄入量显著减少。25 和 100ng 没有效果。20ng（41.4pmol）RF9 NPFF-R 拮抗剂预处理消除了 50ng（37.8pmol）RFRP-1 的作用。在旷场试验中，50ng RFRP-1 不改变动物的自发运动活动，动物的一般行为也没有改变。我们的结果是首次报道，向 CeA 注射 RFRP-1 会导致液体食物消耗减少。这是一种受体相关的作用，因为它被一种选择性的 NPFF-R 拮抗剂消除。
