Endocrine,behavioral and autonomic effects of neuropeptide AF Miklós Jászberényi a , Zsolt Bagosi a , Balázs Thurzó a , Imre Földesi b , Gyula Szabó a , Gyula Telegdy a, ⁎ a Department of Pathophysiology, University of Szeged, H-6701,Szeged, Semmelweis u. 1., PO Box: 427, Hungary b Department of Internal Medicine: Endocrine Unit, University of Szeged, Szeged, Hungary a b s t r a c t a r t i c l e i n f o Article history: Received 16 September 2008 Revised 20 February 2009 Accepted 22 February 2009 Available online 6 March 2009 Keywords: Neuropeptide AF Hypothalamic-pituitary-adrenal axis Corticosterone ACTH Open-field Elevated plus-maze Telemetry Superfusion The actions ofneuropeptide AF (NPAF),on the hypothalamic-pituitary-adrenal (HPA) axis, behavior and autonomic functions were investigated.NPAF (0.25, 0.5, 1, 2 nmol) was administered intracerebro- ventricularly to rats, the behavior of which was monitored by means of telemetry,open-field (OF) observationsand elevated plus-maze (EPM) tests. The temperature and heartrate were recorded by telemetry,and the plasma ACTH and corticosterone levels were used as indices of the HPA activation. The dopamine release from striataland amygdala slices afterpeptide treatment(100 nM and 1 μM) was measured with a superfusion apparatus. To establish the transmission of the HPA response, animals were pretreated with the corticotrophin-releasing hormone (CRH) receptor antagonist antalarmin or astressin 2B (0.5 nmol).In the OF test, the animals were pretreated with antalarmin or haloperidol (10 μg/kg), while in the EPM test they were pretreated with antalarmin or diazepam (1 mg/kg). NPAF stimulated ACTH and corticosterone release, which was inhibited by antalarmin.It activated exploratory locomotion (square crossings and rearings) and grooming in OF observations, and decreased the entries to and the time spent in the open arms during the EPM tests. The antagonists inhibited the locomotor responses, and also attenuated grooming and the EPM responses. NPAF also increased spontaneous locomotion, and tended to decrease the core temperature and the heart rate in telemetry, while it augmented the dopamine release from striatal and amygdala slices. These results demonstrate, that acute administration of exogenous NPAF stimulates the HPA axis and behavioral paradigms through CRH and dopamine release. © 2009 Elsevier Inc. All rights reserved. Introduction Neuropeptide AF (NPAF), which is closely related to neuropeptide FF (NPFF) is a mammalian RFamide neuropeptide. After its discovery ( Yang et al.,1985),it was categorized as an orphan ligand until the identification ofits G protein-coupled receptor (Elshourbagy et al., 2000). It is highly concentrated in the pituitary, hypothalamus and other central nervous system (CNS) regions. Precursor proteins have been identified in the mouse, rat, bovine and human brain (Kivipelto et al., 1989; Panula et al., 1996). Its related peptides are NPFF, prolactin-releasing peptide (PrRP), RFamide-related peptides, metas- tin/Kisspeptins and the most recently identified, pyroglutamylated RFamide peptide, (Fukusumi et al., 2006).They are produced by five different genes (farp-1 to 5),and NPAF and NPFF are alternatively spliced products of the transcription of farp-1. They have an N- terminal sequence homology, but they differ considerably in structure (NPFF contains only 8,and NPAF 18 amino acids) and they bind to different receptors (NPAF to GPR74/NPGPR/HLWAR77/NPFF-2 and NPFF to GPR147/NPFF-1/OT7T022) processed from the product of the same receptor gene rfr-3 (Fukusumi et al., 2006). As concerns RFamide neuropeptides, a great deal of information is available on the function of PrRP, and several papers have dealt with the role of NPFF in the modulation of nociception and other CNS processes. The highest level of PrRP and its receptor have been detected in the hypothalamus,pituitary and medulla oblongata (Fukusumiet al., 2006).The peptide has proved to be a stimulator of prolactin release (Kawamata et al., 2000),and a potent activator of the hypothalamic- pituitary-adrenal(HPA) axis (Matsumoto et al., 2000) and pressor response (Horiuchiet al., 2002). It has also been demonstrated to inhibit feeding (Lawrence et al., 2000), to increase the core temperature (Lawrence et al., 2004) and to facilitate stereotyped (species typical, highly conserved action pattern) behavioral paradigms such as grooming (Lawrence et al., 2002). NPFF, like NPAF, is most abundantly expressed in the hypothalamus, the nucleus of the solitary tract, the amygdala and the thalamus (Kivipelto et al., 1989). Its receptor is predominantly expressed in hypothalamic, thalamic, mesolimbic and brainstem regions (Fukusumi et al., 2006 ). Its role in pain modulation has been thoroughly investigated (Panula et al., 1999),whereas only a few papers have reported that NPFF increases blood pressure (Roth et al., 1987), inhibits feeding (Murase et al., 1996) and locomotion (Cador et al., 2002), and elicits a hypothermic response (Desprat and Zajac, 1997).It seems, therefore,that in some respects the structurally related RFamide Hormones and Behavior 56 (2009) 24–34 ⁎ Corresponding author. Fax: +36 62 545710. E-mail address: telegdy@patph.szote.u-szeged.hu (G. Telegdy). 0018-506X/$ – see front matter © 2009 Elsevier Inc. All rights reserved. doi:10.1016/j.yhbeh.2009.02.006 Contents lists available at ScienceDirect Hormones and Behavior j o u r n a l h o m e p a g e : w w w. e l s ev i e r. c o m / l o c a t e / y h b e h