1
|
Shiraishi JI, Yanagita K, Tanizawa H, Bungo T. Glycyl-l-glutamine attenuates NPY-induced hyperphagia via the melanocortin system. Neurosci Lett 2020; 736:135303. [PMID: 32800923 DOI: 10.1016/j.neulet.2020.135303] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2020] [Revised: 08/03/2020] [Accepted: 08/10/2020] [Indexed: 11/26/2022]
Abstract
This study aimed to determine whether glycyl-l-glutamine (Gly-Gln; β-endorphin (30-31)), a non-opioid peptide derived from β-endorphin processing, modulates neuropeptide Y (NPY)-induced feeding and hypothalamic mRNA expression of peptide hormones in male broiler chicks. Intracerebroventricular injection of NPY (235 pmol) generated a hyperphagic response in ad libitum chicks within 30 min. Co-administration of Gly-Gln (100 nmol) attenuated this response, inducing a 30 % decrease. This was not attributable to Gly-Gln hydrolysis because co-administration of glycine (Gly) and glutamine (Gln) had no effect on NPY-induced hyperphagia. Gly-Gln injected alone also showed no effect. The hypothalamic pro-opiomelanocortin mRNA expression in the co-injection group was significantly higher than that in the NPY alone group. These data indicate that endogenous Gly-Gln may contribute to regulate feeding behavior via the central melanocortin system in chicks and acts as a counter regulator of the neural activity in energy metabolism.
Collapse
Affiliation(s)
- Jun-Ichi Shiraishi
- Laboratory of Applied Animal Biochemistry, Graduate School of Applied Life Science, Nippon Veterinary and Life Science University, Tokyo, 180-8602, Japan.
| | - Kouichi Yanagita
- Laboratory of Animal Behavior and Physiology, Graduate School of Integrated Sciences for Life, Hiroshima University, Higashi-Hiroshima, 739-8528, Japan
| | - Hiroshi Tanizawa
- Laboratory of Animal Behavior and Physiology, Graduate School of Integrated Sciences for Life, Hiroshima University, Higashi-Hiroshima, 739-8528, Japan
| | - Takashi Bungo
- Laboratory of Animal Behavior and Physiology, Graduate School of Integrated Sciences for Life, Hiroshima University, Higashi-Hiroshima, 739-8528, Japan
| |
Collapse
|
2
|
Pharmacological characterization, cellular localization and expression profile of NPY receptor subtypes Y2 and Y7 in large yellow croaker, Larimichthys crocea. Comp Biochem Physiol B Biochem Mol Biol 2019; 238:110347. [PMID: 31499219 DOI: 10.1016/j.cbpb.2019.110347] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2019] [Revised: 09/02/2019] [Accepted: 09/04/2019] [Indexed: 11/23/2022]
Abstract
Neuropeptide Y (NPY) receptors are suggested to mediate the multi-physiological functions of NPY family peptides, such as food intake, in teleost fish. However, the structure and signaling of fish NPY receptors are yet to be fully elucidated. In this study, we report the cloning and characterization of two neuropeptide Y receptor subtypes, Y2 (NPY2R) and Y7 (NPY7R), in yellow croaker Larimichthys crocea (L. crocea) (LcNPY2R, LcNPY7R). The gene structure, pharmacological characterization, cell location, and tissue expression of these two receptors were explored. The phylogenetic results showed that LcNPY2R and LcNPY7R had typical G protein-coupled receptor profiles, associated with the Y2 subfamily, with coding sequences that are highly conserved in vertebrates. The expression of both LcNPY2R and LcNPY7R could be activated by LcNPY in HEK293 cells. However, truncated LcNPY18-36 was only able to activate LcNPY2R at the same level as full length LcNPY. Expression analysis revealed that LcNPY2R mRNA was predominantly expressed in the intestine and liver, whereas LcNPY7R was expressed in the stomach, which indicated that both receptors were related to the digestive system. Overall, our data establishes a molecular basis to determine the actions of LcNPY2R and LcNPY7R, which could be used to elucidate the conserved roles of these receptor-ligand pairs in vertebrates.
Collapse
|
3
|
Gøtzsche CR, Woldbye DPD. The role of NPY in learning and memory. Neuropeptides 2016; 55:79-89. [PMID: 26454711 DOI: 10.1016/j.npep.2015.09.010] [Citation(s) in RCA: 108] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/13/2015] [Revised: 09/29/2015] [Accepted: 09/29/2015] [Indexed: 01/07/2023]
Abstract
High levels of NPY expression in brain regions important for learning and memory together with its neuromodulatory and neurotrophic effects suggest a regulatory role for NPY in memory processes. Therefore it is not surprising that an increasing number of studies have provided evidence for NPY acting as a modulator of neuroplasticity, neurotransmission, and memory. Here these results are presented in relation to the types of memory affected by NPY and its receptors. NPY can exert both inhibitory and stimulatory effects on memory, depending on memory type and phase, dose applied, brain region, and NPY receptor subtypes. Thus NPY act as a resilience factor by impairing associative implicit memory after stressful and aversive events, as evident in models of fear conditioning, presumably via Y1 receptors in the amygdala and prefrontal cortex. In addition, NPY impairs acquisition but enhances consolidation and retention in models depending on spatial and discriminative types of associative explicit memory, presumably involving Y2 receptor-mediated regulations of hippocampal excitatory transmission. Moreover, spatial memory training leads to increased hippocampal NPY gene expression that together with Y1 receptor-mediated neurogenesis could constitute necessary steps in consolidation and long-term retention of spatial memory. Altogether, NPY-induced effects on learning and memory seem to be biphasic, anatomically and temporally differential, and in support of a modulatory role of NPY at keeping the system in balance. Obtaining further insight into memory-related effects of NPY could inspire the engineering of new therapeutics targeting diseases where impaired learning and memory are central elements.
Collapse
Affiliation(s)
- C R Gøtzsche
- Laboratory of Neural Plasticity, Department of Neuroscience and Pharmacology, University of Copenhagen, Denmark.
| | - D P D Woldbye
- Laboratory of Neural Plasticity, Department of Neuroscience and Pharmacology, University of Copenhagen, Denmark
| |
Collapse
|
4
|
Tasan RO, Verma D, Wood J, Lach G, Hörmer B, de Lima TCM, Herzog H, Sperk G. The role of Neuropeptide Y in fear conditioning and extinction. Neuropeptides 2016; 55:111-26. [PMID: 26444585 DOI: 10.1016/j.npep.2015.09.007] [Citation(s) in RCA: 79] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/06/2015] [Revised: 09/10/2015] [Accepted: 09/10/2015] [Indexed: 12/23/2022]
Abstract
While anxiety disorders are the brain disorders with the highest prevalence and constitute a major burden for society, a considerable number of affected people are still treated insufficiently. Thus, in an attempt to identify potential new anxiolytic drug targets, neuropeptides have gained considerable attention in recent years. Compared to classical neurotransmitters they often have a regionally restricted distribution and may bind to several distinct receptor subtypes. Neuropeptide Y (NPY) is a highly conserved neuropeptide that is specifically concentrated in limbic brain areas and signals via at least 5 different G-protein-coupled receptors. It is involved in a variety of physiological processes including the modulation of emotional-affective behaviors. An anxiolytic and stress-reducing property of NPY is supported by many preclinical studies. Whether NPY may also interact with processing of learned fear and fear extinction is comparatively unknown. However, this has considerable relevance since pathological, inappropriate and generalized fear expression and impaired fear extinction are hallmarks of human post-traumatic stress disorder and a major reason for its treatment-resistance. Recent evidence from different laboratories emphasizes a fear-reducing role of NPY, predominantly mediated by exogenous NPY acting on Y1 receptors. Since a reduction of fear expression was also observed in Y1 receptor knockout mice, other Y receptors may be equally important. By acting on Y2 receptors, NPY promotes fear extinction and generates a long-term suppression of fear, two important preconditions that could support cognitive behavioral therapies in human patients. A similar effect has been demonstrated for the closely related pancreatic polypeptide (PP) when acting on Y4 receptors. Preliminary evidence suggests that NPY modulates fear in particular by activation of Y1 and Y2 receptors in the basolateral and central amygdala, respectively. In the basolateral amygdala, NPY signaling activates inhibitory G protein-coupled inwardly-rectifying potassium channels or suppresses hyperpolarization-induced I(h) currents in a Y1 receptor-dependent fashion, favoring a general suppression of neuronal activity. A more complex situation has been described for the central extended amygdala, where NPY reduces the frequency of inhibitory and excitatory postsynaptic currents. In particular the inhibition of long-range central amygdala output neurons may result in a Y2 receptor-dependent suppression of fear. The role of NPY in processes of learned fear and fear extinction is, however, only beginning to emerge, and multiple questions regarding the relevance of endogenous NPY and different receptor subtypes remain elusive. Y2 receptors may be of particular interest for future studies, since they are the most prominent Y receptor subtype in the human brain and thus among the most promising therapeutic drug targets when translating preclinical evidence to potential new therapies for human anxiety disorders.
Collapse
Affiliation(s)
- R O Tasan
- Department of Pharmacology, Medical University Innsbruck, 6020 Innsbruck, Austria.
| | - D Verma
- Institute of Physiology I, University of Münster, D-48149 Münster, Germany
| | - J Wood
- Department of Pharmacology, Medical University Innsbruck, 6020 Innsbruck, Austria
| | - G Lach
- Department of Pharmacology, Medical University Innsbruck, 6020 Innsbruck, Austria; Capes Foundation, Ministry of Education of Brazil, 70040-020 Brasília/DF, Brazil
| | - B Hörmer
- Department of Pharmacology, Medical University Innsbruck, 6020 Innsbruck, Austria
| | - T C M de Lima
- Department of Pharmacology, Federal University of Santa Catarina, 88049-970 Florianópolis, Brazil
| | - H Herzog
- Neuroscience Research Program, Garvan Institute of Medical Research, Darlinghurst, Sydney, NSW 2010, Australia
| | - G Sperk
- Department of Pharmacology, Medical University Innsbruck, 6020 Innsbruck, Austria
| |
Collapse
|
5
|
Wang F, Chen W, Lin H, Li W. Cloning, expression, and ligand-binding characterization of two neuropeptide Y receptor subtypes in orange-spotted grouper, Epinephelus coioides. FISH PHYSIOLOGY AND BIOCHEMISTRY 2014; 40:1693-1707. [PMID: 25007879 DOI: 10.1007/s10695-014-9960-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2014] [Accepted: 06/24/2014] [Indexed: 06/03/2023]
Abstract
As one of the most important multifunctional peptides, neuropeptide Y (NPY) performs its physiological functions through different subtype receptors. In this study, full-length cDNAs of two NPY receptors (YRs) in orange-spotted grouper (Epinephelus coioides) were cloned and named npy8br (y8b) and npy2r (y2). Phylogenetic analysis indicated that the Y8b receptor is an ortholog of the teleostean Y8b receptor, which belongs to the Y1 subfamily, and the Y2 receptor is an ortholog of the teleostean Y2 receptor, which belongs to the Y2 subfamily. Both of the YRs have G protein-coupled receptor family profiles. Multiple alignments demonstrate that the extracellular loop regions of YRs have distinctive residues of each species. Expression profile analysis revealed that the grouper Y8b receptor mRNA is primarily expressed in the brain, stomach and intestine, while the grouper Y2 receptor mRNA is primarily expressed in the brain, ovary, liver and heart. Double immunofluorescence analysis determined that the grouper YRs interact with the grouper NPY around the human embryonic kidney 293T cell surface. Furthermore, site-directed mutagenesis in a phage display system revealed that Asp(6.59) might be a common NPY-binding site, while Asp(2.68) of the Y8b receptor and Glu(5.24) of the Y2 receptor could be likely involved in subtype-specific binding. Combining the expression profile and ligand-binding feature, the grouper Y8b receptor could be involved in regulating food intake via the brain-gut axis and the grouper Y2 receptor might play a role in balancing the regulatory activity of the Y8b receptor and participate in metabolism in the liver and ovary.
Collapse
Affiliation(s)
- Fei Wang
- State Key Laboratory of Biocontrol, Institute of Aquatic Economic Animals, Guangdong Provincial Key Laboratory for Aquatic Economic Animals, School of Life Sciences, Sun Yat-Sen University, Guangzhou, 510275, People's Republic of China
| | | | | | | |
Collapse
|
6
|
Babri S, Amani M, Mohaddes G, Mirzaei F, Mahmoudi F. Effects of intrahippocampal injection of ghrelin on spatial memory in PTZ-induced seizures in male rats. Neuropeptides 2013; 47:355-60. [PMID: 23790400 DOI: 10.1016/j.npep.2013.05.005] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/12/2012] [Revised: 05/23/2013] [Accepted: 05/27/2013] [Indexed: 11/18/2022]
Abstract
Ghrelin (gh) is a peptide hormone that may affect learning and memory. There is some evidence that ghrelin can have antiepileptic effects. So we decided to investigate the possible effects of ghrelin on spatial memory following PTZ-induced seizures in male rats. Ninety male rats were divided into 9 groups including control, saline, ghrelin (0.3, 1.5 or 3 nmol) and pentylenetetrazol (PTZ, 50 mg/kg, i.p.) plus saline or ghrelin (0.3, 1.5 or 3 nmol). All groups were trained in Morris water maze (MWM) for two consecutive days. Our results showed that ghrelin significantly improves spatial memory at the doses of 1.5 or 3 nmol (P<0.05) in normal rats. We also demonstrated the significant impairment of spatial memory in PTZ group (P<0.05). Intrahippocampal injection of ghrelin at the dose of 3 nmol significantly improved spatial memory in PTZ+gh group compared to PTZ group (P<0.05). These findings suggest that ghrelin as a neuropeptide can improve spatial memory in PTZ-treated rats.
Collapse
Affiliation(s)
- Shirin Babri
- Neuroscience Research Center, Tabriz University of Medical Sciences, Tabriz, Iran.
| | | | | | | | | |
Collapse
|
7
|
dos Santos VV, Santos DB, Lach G, Rodrigues ALS, Farina M, De Lima TCM, Prediger RD. Neuropeptide Y (NPY) prevents depressive-like behavior, spatial memory deficits and oxidative stress following amyloid-β (Aβ(1-40)) administration in mice. Behav Brain Res 2013; 244:107-15. [PMID: 23396168 DOI: 10.1016/j.bbr.2013.01.039] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2012] [Revised: 01/25/2013] [Accepted: 01/28/2013] [Indexed: 12/25/2022]
Abstract
Neuropeptide Y (NPY) is a 36-amino acid peptide widely distributed in the central nervous system (CNS) that has been associated with the modulation of several functions including food intake, learning and memory, mood and neuroprotection. There is great interest in understanding the role of NPY in the deleterious effects induced by the central accumulation of amyloid-β (Aβ) peptides, a pathological hallmark of Alzheimer's disease (AD). Herein, we evaluated the effects of a single intracerebroventricular (i.c.v.) administration of NPY (0.0234 μmol/μL) 15 min prior to the i.c.v. injection of aggregated Aβ1-40 peptide (400 pmol/mouse) in behavioral and neurochemical parameters related to oxidative stress in mice. Pretreatment with NPY prevented Aβ1-40-induced depressive-like responses and spatial memory impairments evaluated in the tail suspension and object location tasks, respectively. The protective effects of NPY on spatial memory of Aβ1-40-treated mice were abolished by the pretreatment with the selective Y2 receptor antagonist BIIE0246. On the other hand, the administration of NPY and Aβ1-40 did not alter the performance of the animals in the elevated plus-maze and open field arena, indicating lack of effects on anxiety state and locomotor function. Although Aβ1-40 infusion did not change hippocampal and cortical glutathione peroxidase (GPx) activity and glutathione (GSH) levels, Aβ1-40-infused animals showed an increased lipid peroxidation in hippocampus and prefrontal cortex that were blunted by NPY administration. These findings indicate that central administration of NPY prevents Aβ1-40-induced depressive-like behavior and spatial memory deficits in mice and that this response is mediated, at least in part, by the activation of Y2 receptors and prevention of oxidative stress.
Collapse
Affiliation(s)
- Vanessa V dos Santos
- Programa de Pós-Graduação em Neurociências, Centro de Ciências Biológicas, Universidade Federal de Santa Catarina, UFSC, Florianópolis-SC, Brazil
| | | | | | | | | | | | | |
Collapse
|
8
|
Kong FJ, Tang YW, Lou AF, Chen H, Xu LH, Zhang XM, Lu HS. Effects of isoflurane exposure during pregnancy on postnatal memory and learning in offspring rats. Mol Biol Rep 2011; 39:4849-55. [DOI: 10.1007/s11033-011-1279-z] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2011] [Accepted: 09/15/2011] [Indexed: 12/01/2022]
|
9
|
Walther C, Mörl K, Beck-Sickinger AG. Neuropeptide Y receptors: ligand binding and trafficking suggest novel approaches in drug development. J Pept Sci 2011; 17:233-46. [PMID: 21351324 DOI: 10.1002/psc.1357] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2010] [Revised: 12/22/2010] [Accepted: 01/07/2011] [Indexed: 12/27/2022]
Abstract
NPY, PYY and PP constitute the so-called NPY hormone family, which exert its biological functions in humans through YRs (Y₁, Y₂, Y₄ and Y₅). Systematic modulation of YR function became important as this multireceptor/multiligand system is known to mediate various essential physiological key functions and is involved in a variety of major human diseases such as epilepsy, obesity and cancer. As several YRs have been found to be overexpressed on different types of malignant tumors they emerge as promising target in modern drug development. Here, we summarize the current understanding of YRs function and the molecular mechanisms of ligand binding and trafficking. We further address recent advances in YR-based drug design, the development of promising future drug candidates and novel approaches in YR-targeted tumor diagnostics and therapy opportunities.
Collapse
Affiliation(s)
- Cornelia Walther
- Institute of Biochemistry, Faculty of Biosciences, Pharmacy and Psychology, Leipzig University, Leipzig, Germany
| | | | | |
Collapse
|
10
|
Böhme I, Stichel J, Walther C, Mörl K, Beck-Sickinger AG. Agonist induced receptor internalization of neuropeptide Y receptor subtypes depends on third intracellular loop and C-terminus. Cell Signal 2008; 20:1740-9. [DOI: 10.1016/j.cellsig.2008.05.017] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2008] [Accepted: 05/26/2008] [Indexed: 10/22/2022]
|
11
|
Sørensen AT, Kanter-Schlifke I, Carli M, Balducci C, Noe F, During MJ, Vezzani A, Kokaia M. NPY gene transfer in the hippocampus attenuates synaptic plasticity and learning. Hippocampus 2008; 18:564-74. [DOI: 10.1002/hipo.20415] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
|
12
|
Merten N, Lindner D, Rabe N, Römpler H, Mörl K, Schöneberg T, Beck-Sickinger AG. Receptor Subtype-specific Docking of Asp6.59 with C-terminal Arginine Residues in Y Receptor Ligands. J Biol Chem 2007; 282:7543-51. [PMID: 17204471 DOI: 10.1074/jbc.m608902200] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Y receptors (YRs) are G protein-coupled receptors whose Y(1)R, Y(2)R, and Y(5)R subtypes preferentially bind neuropeptide Y (NPY) and peptide YY, whereas mammalian Y(4)Rs show a higher affinity for pancreatic polypeptide (PP). Comparison of YR orthologs and paralogs revealed Asp(6.59) to be fully conserved throughout all of the YRs reported so far. By replacing this conserved aspartic acid residue with alanine, asparagine, glutamate, and arginine, we now show that this residue plays a crucial role in binding and signal transduction of NPY/PP at all YRs. Sensitivity to distinct replacements is, however, receptor subtype-specific. Next, we performed a complementary mutagenesis approach to identify the contact site of the ligand. Surprisingly, this conserved residue interacts with two different ligand arginine residues by ionic interactions; although in Y(2)R and Y(5)R, Arg(33) is the binding partner of Asp(6.59), in Y(1)R and Y(4)R, Arg(35) of human PP and NPY interacts with Asp(6.59). Furthermore, Arg(25) of PP and NPY is involved in ligand binding only at Y(2)R and Y(5)R. This suggests significant differences in the docking of YR ligands between Y(1/4)R and Y(2/5)R and provides new insights into the molecular binding mode of peptide agonists at GPCRs. Furthermore, the proposed model of a subtype-specific binding mode is in agreement with the evolution of YRs.
Collapse
Affiliation(s)
- Nicole Merten
- Institute of Biochemistry, Faculty of Bioscience, Pharmacy and Psychology, University of Leipzig, Brüderstrasse 34, 04103 Leipzig, Germany
| | | | | | | | | | | | | |
Collapse
|
13
|
Merten N, Beck-Sickinger AG. Molecular ligand-receptor interaction of the NPY/PP peptide family. EXS 2006:35-62. [PMID: 16382996 DOI: 10.1007/3-7643-7417-9_3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Affiliation(s)
- Nicole Merten
- Institute of Biochemistry, Brüderstr. 34, 04103 Leipzig, Germany
| | | |
Collapse
|
14
|
Cougnon N, Hudspith MJ, Munglani R. The therapeutic potential of neuropeptide Y in central nervous system disorders with special reference to pain and sympathetically maintained pain. Expert Opin Investig Drugs 2005; 6:759-69. [PMID: 15989639 DOI: 10.1517/13543784.6.6.759] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Neuropeptide Y (NPY), a widely distributed peptide, has been shown to have numerous effects in both the central and peripheral nervous systems. In particular, NPY has an important role in mediating analgesia and hyperalgesia by distinct central and peripheral mechanisms. At least six NPY receptor subtypes are known to exist and the development of subtype-specific ligands targeted at NPY receptors will offer novel therapeutic agents. This article will review the involvement of NPY in diverse pathologies of the nervous system, including pain, and will propose a role for NPY in the maintenance of sympathetically maintained pain.
Collapse
Affiliation(s)
- N Cougnon
- Cambridge University Department of Anaesthesia, Addenbrookes Hospital, Cambridge CB2 QQ, UK
| | | | | |
Collapse
|
15
|
Abstract
Intracerebroventricular injection of neuropeptide Y (NPY) produces potent 'anxiolytic' effects in animal models of anxiety. Administration of opioid receptor antagonists suppresses NPY-induced food intake and thermogenesis. The present study examined whether the opiate antagonist naloxone would also suppress the 'anxiolytic' effects of neuropeptide Y. Following training and stabilization of responding in an operant conflict model of anxiety, rats were injected with either NPY or diazepam. Both NPY (veh., 2, 4, 6 microg, i.c.v.) and chlordiazepoxide (veh., 2, 4, 6 mg/kg, i.p.) produced a dose-dependent increase in punished responding in the conflict test. The 'anxiolytic' effects of NPY were not blocked by the administration of flumazenil (3, 6, 12 mg/kg, i.p.). The administration of naloxone (0.25-2.0 mg/kg, s.c.) antagonized the effects of NPY. Central administration of the selective mu opiate antagonist CTAP (1 microg, i.c.v.) partially blocked NPY-induced conflict responding. These results support the hypothesis that NPY may play an important role in experimental anxiety independent of the benzodiazepine receptor and further implicate the opioid system in the behavioral expression of anxiety.
Collapse
Affiliation(s)
- K T Britton
- Department of Psychiatry, San Diego VA Medical Center and University of California, San Diego, CA 92161, USA.
| | | |
Collapse
|
16
|
Rasmusson AM, Hauger RL, Morgan CA, Bremner JD, Charney DS, Southwick SM. Low baseline and yohimbine-stimulated plasma neuropeptide Y (NPY) levels in combat-related PTSD. Biol Psychiatry 2000; 47:526-39. [PMID: 10715359 DOI: 10.1016/s0006-3223(99)00185-7] [Citation(s) in RCA: 177] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
BACKGROUND Consistent with many studies demonstrating enhanced reactivity of the sympathetic nervous system in posttraumatic stress disorder (PTSD), the administration of yohimbine, a noradrenergic alpha(2)-antagonist, has been shown to increase core symptoms of PTSD and to induce greater increases in plasma 3-methyl-4-hydroxy-phenyl-glycol (MHPG) in subjects with PTSD compared with healthy control subjects. In turn, neuropeptide Y (NPY) has been shown to inhibit the release of norepinephrine from sympathetic noradrenergic neurons. METHODS In the following study, plasma NPY responses to yohimbine and placebo were measured in a subgroup of 18 subjects with PTSD and 8 healthy control subjects who participated in the previous study of the effect of yohimbine on plasma MHPG. RESULTS The PTSD subjects had lower baseline plasma NPY and blunted yohimbine-stimulated increases in plasma NPY compared with the healthy control subjects. Within the PTSD group, baseline plasma NPY levels correlated negatively with combat exposure scale scores, baseline PTSD and panic symptoms, and yohimbine-stimulated increases in MHPG and systolic blood pressure. CONCLUSIONS This study suggests that combat stress-induced decreases in plasma NPY may mediate, in part, the noradrenergic system hyperreactivity observed in combat-related PTSD. The persistence of this decrease in plasma NPY may contribute to symptoms of hyperarousal and the expression of exaggerated alarm reactions, anxiety reactions, or both in combat veterans with PTSD long after war.
Collapse
Affiliation(s)
- A M Rasmusson
- VA Connecticut Healthcare System and National Center for PTSD, West Haven and the Department of Psychiatry, Yale University School of Medicine, New Haven, Connecticut, USA
| | | | | | | | | | | |
Collapse
|
17
|
Bracci-Laudiero L, Aloe L, Lundeberg T, Theodorsson E, Stenfors C. Altered levels of neuropeptides characterize the brain of lupus prone mice. Neurosci Lett 1999; 275:57-60. [PMID: 10554984 DOI: 10.1016/s0304-3940(99)00737-5] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
It has been reported that more than 50% of lupus patients show various forms of neurological deficits including impaired cognitive functions and psychiatric disorders. Using an animal model of lupus we investigated the production of neuropeptides in the brain of NZB/W F1 female hybrid mice and its parental strain NZB and NZW. Our results indicate that the alteration in learning and memory described in lupus mice are paralleled by a decrease in calcitonin gene-related peptide, substance P and neuropeptide Y (NPY) levels in the hippocampus and a significant decrease of NPY in the cortex. These findings are interesting in the light of previously reported results suggesting that these neuropeptides can play an important role in cognitive functions. We also observed a decrease of NPY and vasoactive intestinal polypeptide levels in the hypothalamus of lupus prone mice and these changes may be related to the disregulation of the hypothalamus-pituitary-adrenal axis observed in lupus prone mice.
Collapse
Affiliation(s)
- L Bracci-Laudiero
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden.
| | | | | | | | | |
Collapse
|
18
|
Picker MJ, Allen RM, Morgan D, Levine AS, O'Hare E, Cleary JP. Effects of neuropeptide Y on the discriminative stimulus and antinociceptive properties of morphine. Pharmacol Biochem Behav 1999; 64:161-4. [PMID: 10495011 DOI: 10.1016/s0091-3057(99)00110-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Previous research indicates that opioid receptor blockade diminishes the effects of neuropeptide Y (NPY) on feeding and memory. Conversely, NPY attenuates naloxone-precipitated morphine withdrawal. The present study evaluated the effects of NPY on the discriminative stimulus and antinociceptive effects produced by the prototypical mu opioid, morphine. Rats were trained to discriminate 5.6 mg/kg morphine (IP) from saline using a standard two-lever, food-reinforced, drug discrimination procedure. Across a range of doses (3.0, 5.0, and 10 microg), intracerebroventricular (ICV) injection of NPY failed to substitute for, antagonize, or potentiate the discriminative stimulus effects of morphine. A warm-water tail-withdrawal procedure was used to examine the antinociceptive effects of morphine and NPY, alone and in combination. NPY (3.0 and 10 microg, ICV) failed to alter tail-withdrawal latencies from 52 degrees and 56 degrees C water, whereas morphine (1.0-30 mg/kg, IP) produced a dose-related increase in latencies at both water temperatures. A 10-microg dose of NPY also failed to alter the antinociceptive effects of morphine. This study does not support the idea that the discriminative stimulus and antinociceptive effects of morphine are dependent on an NPYergic pathway.
Collapse
Affiliation(s)
- M J Picker
- Department of Psychology, University of North Carolina at Chapel Hill, 27599-3270, USA
| | | | | | | | | | | |
Collapse
|
19
|
Whittaker E, Vereker E, Lynch MA. Neuropeptide Y inhibits glutamate release and long-term potentiation in rat dentate gyrus. Brain Res 1999; 827:229-33. [PMID: 10320715 DOI: 10.1016/s0006-8993(99)01302-5] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The effect of intracerebroventricular injection of neuropeptide Y (NPY) was assessed on LTP in dentate gyrus. We report that NPY attenuated LTP and inhibited KCl-induced glutamate release in synaptosomes prepared from dentate gyrus. Activity of the stress-activated kinase, c-Jun NH2-terminal kinase (JNK) in synaptosomes was increased by incubation with NPY or following intracerebroventricular injection. Activation of JNK might underlie the inhibitory effect of NPY on LTP.
Collapse
Affiliation(s)
- E Whittaker
- Department of Physiology, Trinity College, Dublin 2, Ireland
| | | | | |
Collapse
|
20
|
Delalle I, Evers P, Kostović I, Uylings HB. Laminar distribution of neuropeptide Y-immunoreactive neurons in human prefrontal cortex during development. J Comp Neurol 1997; 379:515-22. [PMID: 9067840 DOI: 10.1002/(sici)1096-9861(19970324)379:4<515::aid-cne4>3.0.co;2-5] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Neuropeptide Y (NPY) is present in neurons of the adult human cerebral cortex. In view of the reported roles of NPY in the central nervous system in health and during certain disease conditions, we have studied normal development of NPY immunoreactivity (-ir) in the human prefrontal cortex (PFC), Brodmann areas 9 and 46. Twenty-six specimens ranging from the ages of 14 postovulatory weeks to 34 years exhibited patterns that revealed six periods in the development of the laminar distribution and density of NPY-ir neurons. Changes during prenatal and perinatal periods reflect the onset, development, and resolution of the transient fetal telencephalic compartments, including the subplate zone, in which NPY-ir neurons are especially abundant. Before the age of 1 year, the majority of NPY-ir neurons were found in the subplate zone, whereas, after 1 year, the majority were seen in the cortical layers. This is in contrast with the human visual cortex, where the majority of NPY-ir neurons were still located in the white matter. The density of cortical NPY-ir neurons increased in the fifth developmental period (ages 4-7 years), coinciding with the increase of cortical volume and marked progression of cognitive functions. The adult pattern of a relatively low density of cortical NPY-ir neurons was reached in period 6 (from about 8 years), when individual variation also became apparent. Our data point to a protracted maturation of NPY-ir in the human PFC and to different distribution patterns of NPY-ir neurons in different cortical areas.
Collapse
Affiliation(s)
- I Delalle
- Croatian Institute for Brain Research, School of Medicine, University of Zagreb, Croatia
| | | | | | | |
Collapse
|
21
|
Rudski JM, Grace M, Kuskowski MA, Billington CJ, Levine AS. Behavioral effects of naloxone on neuropeptide Y-induced feeding. Pharmacol Biochem Behav 1996; 54:771-7. [PMID: 8853202 DOI: 10.1016/0091-3057(96)00019-6] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
We evaluated the effect of naloxone on neuropeptide Y (NPY)-induced feeding behavior using two methods; operant chambers and observational analysis. In the first study rats were trained on a FR 80 (first pellet) FR 3 (subsequent pellets) reinforcement schedule. Following training, rats were injected with NPY (intraventricular, 5 micrograms) and various doses of naloxone (subcutaneous, 0, 0.1, 0.3, 1, 3, and 10 mg/kg). NPY significantly increased the number of pellets consumed during the one hour session and naloxone (1, 3, and 10 mg/kg) blocked this effect. NPY failed to alter the time to the first response, but did decrease the time needed to complete the first ratio (FR 80). Naloxone (3 and 10 mg/kg) increased the latency to the first response and blocked NPY's effect on completion of the first ratio. In the second study, we observed rats continually following injection of saline. NPY (5 micrograms i.c.v.) and/or naloxone (1 mg/kg s.c.). NPY increased food intake during the 1-h session and naloxone blocked this effect. NPY decreased the latency to eat, but naloxone failed to significantly antagonize this effect. The amount of time spent eating was greater in the NPY group compared to the saline group and naloxone antagonized this effect. Lag sequential analysis indicated that NPY induced a move-eat-move behavioral sequence that disappeared following naloxone administration. These data lend support to the notion that opioids are involved in maintenance of NPY-induced feeding but affect meal initiation in a minor way. Only relatively high doses of naloxone (3 and 10 mg/kg) altered NPY-induced changes in meal initiation.
Collapse
Affiliation(s)
- J M Rudski
- Veterans Affairs Medical Center, Research Service (151), Minneapolis, MN 55417, USA
| | | | | | | | | |
Collapse
|
22
|
Cleary J, Hittner JM, Semotuk M, Mantyh P, O'Hare E. Beta-amyloid(1-40) effects on behavior and memory. Brain Res 1995; 682:69-74. [PMID: 7552329 DOI: 10.1016/0006-8993(95)00323-i] [Citation(s) in RCA: 66] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Beta amyloid 1-40 is a primary protein in plaques found in the brains of patients with Alzheimer's disease. There is evidence that unaggregated soluble beta-amyloid may be neurotoxic and may have behavioral effects on some types of memory. In the current study, the 1-40 fragment of beta-amyloid protein (beta A4), or vehicle, was bilaterally injected into the rostral hippocampus of rats performing under stable food-maintained schedules of reinforcement or under a delayed conditional discrimination procedure. Under the first procedure, rats were trained to stability under a multiple fixed interval 15 s, fixed ratio 30 reinforcement schedule. This reinforcement schedule has proven sensitive to low-dose drug effects. Acute bilateral hippocampal beta A4 (1.0, 2.0 and 3.0 microliters of 10(-3) M) administration did not significantly alter responding, compared to vehicle, under either reinforcement condition. Following the acute single-injection regimen, rats were administered chronic daily beta A4 (1 microliter of 10(-3) M), bilaterally, for 15 days. No significant changes in lever-pressing performance were observed during the chronic injection regimen, but performance declined significantly 30 days after termination of the chronic daily regimen. Histological examination revealed three of six rats showed positive reactions under Thioflavin S staining in and around the area of cannulae termination. The second assessment employed a delayed conditional discrimination procedure to evaluate the effects of intrahippocampal injections of beta A4 on short-term working memory. This conditional discrimination procedure assesses appropriate responding, dependent on a previously presented stimulus, after delays of various lengths have been imposed between the stimulus and the response opportunity.(ABSTRACT TRUNCATED AT 250 WORDS)
Collapse
Affiliation(s)
- J Cleary
- GRECC (11G), Veterans Affairs Medical Center, Minneapolis, MN 55417, USA
| | | | | | | | | |
Collapse
|
23
|
Abstract
Neuropeptide Y (NPY) is a 36-amino acid peptide belonging to the pancreatic polypeptide family that has marked and diverse biological activity across species. NPY originally was isolated from mammalian brain tissue somewhat more than 10 years ago and, since that time, has been the subject of numerous scientific publications. NPY and its proposed three receptors (Y1, Y2 and Y3) are relatively abundant in and uniquely distributed throughout the brain and spinal cord. This review will highlight the results from a number of research-oriented studies that have examined how NPY is involved in CNS function and behavior, and how these studies may relate to the possible development of medicines, either NPY-like agonists or antagonists, directed towards the treatment of disorders such as anxiety, pain, hypertension, schizophrenia, memory dysfunction, abnormal eating behavior and depression.
Collapse
|
24
|
Abstract
This article is the 17th installment of our annual review of research concerning the opiate system. It includes papers published during 1994 involving the behavioral, nonanalgesic, effects of the endogenous opiate peptides. The specific topics covered this year include stress; tolerance and dependence; eating; drinking; gastrointestinal, renal, and hepatic function; mental illness and mood; learning, memory, and reward; cardiovascular responses; respiration and thermoregulation; seizures and other neurological disorders; electrical-related activity; general activity and locomotion; sex, pregnancy, and development; immunological responses; and other behaviors.
Collapse
Affiliation(s)
- G A Olson
- Department of Psychology, University of New Orleans, LA 70148, USA
| | | | | |
Collapse
|