Glucagon-like peptide-1 (GLP-1) receptor agonists are indicated for the treatment of Type 2 diabetes and obesity, but can cause nausea and emesis in some patients. GLP-1 receptors are distributed widely in the brain, where they contribute to mechanisms of emesis, reduced appetite and aversion, but it is not known if these centrally located receptors also contribute to a modulation of gastric slow wave activity, which is linked causally to nausea. Our aim was to investigate the potential of the GLP-1 receptor agonist, exendin-4, administered into the 3rd ventricle to modulate emesis, feeding and gastric slow wave activity. Thermoregulation and cardiovascular parameters were also monitored, as they are disturbed during nausea.Ferrets were used as common laboratory rodents do not have an emetic reflex. A guide cannula was implanted into the 3rd ventricle for delivering a previously established dose of exendin-4 (10 nmol), which had been shown to induce emesis and behaviours indicative of 'nausea'. Radiotelemetry recorded gastric myoelectric activity (GMA; slow waves), blood pressure and heart rate variability (HRV), and core temperature; food intake and behaviour were also assessed.Exendin-4 (10 nmol, i.c.v.) decreased the dominant frequency of GMA, with an associated increase in the percentage of bradygastric power (lasting ~ 4 h). Food intake was inhibited in all animals, with 63% exhibiting emesis. Exendin-4 also increased blood pressure (lasting ~ 24 h) and heart rate (lasting ~ 7 h), decreased HRV (lasting ~ 24 h), and caused transient hyperthermia. None of the above parameters were emesis-dependent.The present study shows for the first time that gastric slow waves may be modulated by GLP-1 receptors in the brain through mechanisms that appear independent from emesis. Taken together with a reduction in HRV, the findings are consistent with changes associated with the occurrence of nausea in humans.

It is over 30years since the regulatory peptide galanin was discovered by Professor Mutt and co-workers. Galanin exerts its effects by binding to three galanin G-protein coupled receptors, namely GAL1R, GAL2R and GAL3R. Each galanin receptor has a different distribution in the central nervous system and the peripheral nervous system as well as distinctive signaling pathways, which implicates that the receptors are involved in different biological- and pathological effects. The delineation of the galaninergic system is however difficult due to a lack of stable, specific galanin receptor ligands. Herein, a new short GAL2R specific ligand, Ala5-galanin (2-11), is presented. The galanin (2-11) modified analogue Ala5-galanin (2-11) was tested in 125I-galanin competitive binding studies for the three galanin receptors and the G-protein coupled receptor signaling properties was tested by the ability to influence second-messenger molecules like inositol phosphate and cyclic adenosine monophosphate. In addition, two different label-free real-time assays, namely EnSpire® based on an optical biosensor and xCELLigence® based on an electric biosensor, were used for evaluating the signaling properties using cell lines with different levels of receptor expression. Ala5-galanin (2-11) was subsequently found to be a full agonist for GAL2R with more than 375-fold preference for GAL2R compared to both GAL1R and GAL3R. The single amino acid substitution of serine to alanine at position 5 in the short ligand galanin (2-11) resulted in a ligand subsequently unable to bind neither GAL3R nor GAL1R, even at concentrations as high as 0.1mM.

The neuropeptide galanin is widely distributed in the central and peripheral nervous systems and part of a bigger family of bioactive peptides. Galanin exerts its biological activity through three G-protein coupled receptor subtypes, GAL1-3R. Throughout the last 20years, data has accumulated that galanin can have a neuroprotective effect presumably mediated through the activation of GAL1R and GAL2R. In order to test the pharmaceutical potential of galanin receptor subtype selective ligands to inhibit excitotoxic cell death, the GAL1R selective ligand M617 and the GAL2R selective ligand M1145 were compared to the novel GAL1/2R ligand M1154, in their ability to reduce the excitotoxic effects of intracerebroventricular injected kainate acid in rats. The peptide ligands were evaluated in vitro for their binding preference in a competitive (125)I-galanin receptor subtype binding assay, and G-protein signaling was evaluated using both classical signaling and a label-free real-time technique. Even though there was no significant difference in the time course or severity of the kainic acid induced epileptic behavior in vivo, administration of either M617 or M1154 before kainic acid administration significantly attenuated the neuronal cell death in the hippocampus. Our results indicate the potential therapeutic value of agonists selective for GAL1R in the prevention of neuronal cell death.

It is over 30 years since the regulatory peptide galanin was discovered by Professor Mutt and co-workers. Galanin exerts its effects by binding to three galanin G-protein coupled receptors, namely GAL(1)R, GAL(2)R and GAL(3)R. Each galanin receptor has a different distribution in the central nervous system and the peripheral nervous system as well as distinctive signaling pathways, which implicates that the receptors are involved in different biological and pathological effects. The delineation of the galaninergic system is however difficult due to a lack of stable, specific galanin receptor ligands. Herein, a new short GAL(2)R specific ligand, Alas-galanin (2-11), is presented. The galanin (2-11) modified analogue Alas-galanin (2-11) was tested in I-125-galanin competitive binding studies for the three galanin receptors and the G-protein coupled receptor signaling properties was tested by the ability to influence second-messenger molecules like inositol phosphate and cyclic adenosine monophosphate. In addition, two different label-free real-time assays, namely EnSpire (R) based on an optical biosensor and xCELLigence (R) based on an electric biosensor, were used for evaluating the signaling properties using cell lines with different levels of receptor expression. Alas-galanin (2-11) was subsequently found to be a full agonist for GAL(2)R with more than 375-fold preference for GAL(2)R compared to both GAL(1)R and GAL(3)R. The single amino acid substitution of serine to alanine at position 5 in the short ligand galanin (2-11) resulted in a ligand subsequently unable to bind neither GAL(3)R nor GAL(1)R, even at concentrations as high as 0.1 mM. (C) 2016 The Authors. Published by Elsevier Ltd.

Galanin and its receptors (GAL1, GAL2, GAL3) modulate a range of neuronal, immune and vascular activities. In vivo administration of SNAP 37889 (1-phenyl-3-[[3-(trifluoromethyl)phenyl]imino]-1H-indol-2-one), a potent small non-peptidergic antagonist of GAL3, was reported to reduce anxiety- and depression-related behavior, ethanol consumption, and antagonizes the effect of galanin on plasma extravasation in rodent models. Accordingly, SNAP 37889 has been proposed as a potential therapeutic agent to treat anxiety and depression disorders. Therefore, we evaluated the toxicity of SNAP 37889 to different cell types. Our experiments revealed that SNAP 37889 (≥10μM) induced apoptosis in epithelial (HMCB) and microglial (BV-2) cell lines expressing endogenous GAL3, in peripheral blood mononuclear cells and promyelocytic leukemia cells (HL-60) expressing GAL2, and in a neuronal cell line (SH-SY5Y) lacking galanin receptor expression altogether. In conclusion, SNAP 37889 is toxic to a variety of cell types independent of GAL3 expression. We caution that the clinical use of SNAP 37889 at doses that might be used to treat anxiety- or depression- related diseases could have unexpected non-galanin receptor-mediated toxicity, especially on immune cells.

The neuropeptide galanin (GAL) is widely distributed in the central and peripheral nervous systems. It is a modulator of various physiological and pathological processes, and it mediates its effects via three G protein-coupled receptors (GAL(1-3) receptors). A role for GAL as a modulator of mood and anxiety was suggested, because GAL and its receptors are highly expressed in limbic brain structures of rodents. In recent years, numerous studies of animal models have suggested an involvement of GAL and GAL(1) and GAL(2) receptors in anxiety-and depression-related behavior. However, to date, there is sparse literature implicating GAL(3) receptors in behavioral functions. Therefore, we studied the behavior of GAL(3) receptor-deficient (GAL(3)-KO) mice to elucidate whether GAL(3) receptors are involved in mediating behavior-associated actions of GAL. The GAL(3)-KO mouse line exhibited normal breeding and physical development. In addition to behavioral tests, phenotypic characterization included analysis of hematology, amino acid profiles, metabolism, and sudomotor function. In contrast to WT littermates, male GAL(3)-KO mice exhibited an anxiety-like phenotype in the elevated plus maze, open field, and light/dark box tests, and they were less socially affiliated than WT animals to a stranger mouse in a social interaction test. In conclusion, our data suggest involvement of GAL(3) receptors in GAL-mediated effects on mood, anxiety, and behavior, making it a possible target for alternative treatment strategies for mood disorders.

Event Abstract Back to Event Expression of the galanin system in immune cells: hypothetical key players of the immune response. Rodolfo Bianchini1*, Andreas Koller1, Andreas Lang1, Silke Wiesmayr2, Bernhard Brodowicz1, Edith Mueller1 and Barbara Kofler1 1 Paracelsus Medical University, Department of Pediatrics, Austria 2 Paracelsus Medical University, Department of Pediatrics, Austria Neuropeptides participate in innate immunity and tolerance. Galanin is a neuropeptide with a widespread distribution in the central and peripheral nervous systems. Several in vivo studies indicate that galanin plays a role in inflammation. The aim of the present study was to identify immune cells expressing components of the galanin system including, not only the peptide but also its three receptors (GalR1-3). Quantitative RT-PCR analysis was performed on mRNA isolated from different types of human primary immune cells as well as human immune cell lines. We observed the expression of galanin in NK cells, skin mast cells, monocyte and macrophages. Accordingly, galanin expression was detected in the human mast cell line LDA2 and human monocyte cell line THP1. The analysis of GalR1, GalR2 and GalR3 revealed variable expression, which did not correlate with each other. GalR1 was only expressed by skin mast cells and THP1. GalR2 was detected in polymorphonuclear cells (PMNs), monocytes, macrophages, skin mast cells, LDA2 and THP1. GalR3mRNA expression was observed in monocytes, LDA2 and THP1. Moreover, flow cytometric analyses (FACS) revealed expression of GalR3 on T cells, monocytes, B cells and a minority of PMNs. Our results show the presence of galanin and GalRs in several types of immune cells. Experiments on different types of immune cells are under way to elucidate the functional role of galanin on immune cells expressing GalRs. Funding: Austrian Research Promotion Agency (FFG: 822782/THERAPEP) Keywords: Neuropeptides, immune cell expression, Galanin, galanin receptors, RT-PCR Conference: 15th International Congress of Immunology (ICI), Milan, Italy, 22 Aug - 27 Aug, 2013. Presentation Type: Abstract Topic: Immune-mediated disease pathogenesis Citation: Bianchini R, Koller A, Lang A, Wiesmayr S, Brodowicz B, Mueller E and Kofler B (2013). Expression of the galanin system in immune cells: hypothetical key players of the immune response.. Front. Immunol. Conference Abstract: 15th International Congress of Immunology (ICI). doi: 10.3389/conf.fimmu.2013.02.00807 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 24 Jun 2013; Published Online: 22 Aug 2013. * Correspondence: Dr. Rodolfo Bianchini, Paracelsus Medical University, Department of Pediatrics, Salzburg, Salzburg, A-5020, Austria, r.bianchini@salk.at Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Rodolfo Bianchini Andreas Koller Andreas Lang Silke Wiesmayr Bernhard Brodowicz Edith Mueller Barbara Kofler Google Rodolfo Bianchini Andreas Koller Andreas Lang Silke Wiesmayr Bernhard Brodowicz Edith Mueller Barbara Kofler Google Scholar Rodolfo Bianchini Andreas Koller Andreas Lang Silke Wiesmayr Bernhard Brodowicz Edith Mueller Barbara Kofler PubMed Rodolfo Bianchini Andreas Koller Andreas Lang Silke Wiesmayr Bernhard Brodowicz Edith Mueller Barbara Kofler Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.