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Clark RM, Clark CM, Lewis KE, Dyer MS, Chuckowree JA, Hoyle JA, Blizzard CA, Dickson TC. Intranasal neuropeptide Y1 receptor antagonism improves motor deficits in symptomatic SOD1 ALS mice. Ann Clin Transl Neurol 2023; 10:1985-1999. [PMID: 37644692 PMCID: PMC10647012 DOI: 10.1002/acn3.51885] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2023] [Accepted: 08/09/2023] [Indexed: 08/31/2023] Open
Abstract
OBJECTIVE Neuropeptide Y (NPY) is a 36 amino acid peptide widely considered to provide neuroprotection in a range of neurodegenerative diseases. In the fatal motor neuron disease amyotrophic lateral sclerosis (ALS), recent evidence supports a link between NPY and ALS disease processes. The goal of this study was to determine the therapeutic potential and role of NPY in ALS, harnessing the brain-targeted intranasal delivery of the peptide, previously utilised to correct motor and cognitive phenotypes in other neurological conditions. METHODS To confirm the association with clinical disease characteristics, NPY expression was quantified in post-mortem motor cortex tissue of ALS patients and age-matched controls. The effect of NPY on ALS cortical pathophysiology was investigated using slice electrophysiology and multi-electrode array recordings of SOD1G93A cortical cultures in vitro. The impact of NPY on ALS disease trajectory was investigated by treating SOD1G93A mice intranasally with NPY and selective NPY receptor agonists and antagonists from pre-symptomatic and symptomatic phases of disease. RESULTS In the human post-mortem ALS motor cortex, we observe a significant increase in NPY expression, which is not present in the somatosensory cortex. In vitro, we demonstrate that NPY can ameliorate ALS hyperexcitability, while brain-targeted nasal delivery of NPY and a selective NPY Y1 receptor antagonist modified survival and motor deficits specifically within the symptomatic phase of the disease in the ALS SOD1G93A mouse. INTERPRETATION Taken together, these findings highlight the capacity for non-invasive brain-targeted interventions in ALS and support antagonism of NPY Y1Rs as a novel strategy to improve ALS motor function.
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Affiliation(s)
- Rosemary M. Clark
- Menzies Institute for Medical ResearchUniversity of TasmaniaHobartTasmania7000Australia
| | - Courtney M. Clark
- Menzies Institute for Medical ResearchUniversity of TasmaniaHobartTasmania7000Australia
| | - Katherine E.A. Lewis
- Menzies Institute for Medical ResearchUniversity of TasmaniaHobartTasmania7000Australia
| | - Marcus S. Dyer
- Menzies Institute for Medical ResearchUniversity of TasmaniaHobartTasmania7000Australia
| | - Jyoti A. Chuckowree
- Menzies Institute for Medical ResearchUniversity of TasmaniaHobartTasmania7000Australia
| | - Joshua A. Hoyle
- Menzies Institute for Medical ResearchUniversity of TasmaniaHobartTasmania7000Australia
| | - Catherine A. Blizzard
- Tasmanian School of Medicine, College of Health and MedicineUniversity of TasmaniaHobartTasmania7000Australia
| | - Tracey C. Dickson
- Menzies Institute for Medical ResearchUniversity of TasmaniaHobartTasmania7000Australia
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Cattaneo S, Verlengia G, Marino P, Simonato M, Bettegazzi B. NPY and Gene Therapy for Epilepsy: How, When,... and Y. Front Mol Neurosci 2021; 13:608001. [PMID: 33551745 PMCID: PMC7862707 DOI: 10.3389/fnmol.2020.608001] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2020] [Accepted: 12/21/2020] [Indexed: 12/18/2022] Open
Abstract
Neuropeptide Y (NPY) is a neuropeptide abundantly expressed in the mammalian central and peripheral nervous system. NPY is a pleiotropic molecule, which influences cell proliferation, cardiovascular and metabolic function, pain and neuronal excitability. In the central nervous system, NPY acts as a neuromodulator, affecting pathways that range from cellular (excitability, neurogenesis) to circuit level (food intake, stress response, pain perception). NPY has a broad repertoire of receptor subtypes, each activating specific signaling pathways in different tissues and cellular sub-regions. In the context of epilepsy, NPY is thought to act as an endogenous anticonvulsant that performs its action through Y2 and Y5 receptors. In fact, its overexpression in the brain with the aid of viral vectors can suppress seizures in animal models of epilepsy. Therefore, NPY-based gene therapy may represent a novel approach for the treatment of epilepsy patients, particularly for pharmaco-resistant and genetic forms of the disease. Nonetheless, considering all the aforementioned aspects of NPY signaling, the study of possible NPY applications as a therapeutic molecule is not devoid of critical aspects. The present review will summarize data related to NPY biology, focusing on its anti-epileptic effects, with a critical appraisal of key elements that could be exploited to improve the already existing NPY-based gene therapy approaches for epilepsy.
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Affiliation(s)
- Stefano Cattaneo
- Vita-Salute San Raffaele University, Milan, Italy.,San Raffaele Scientific Institute, Milan, Italy
| | - Gianluca Verlengia
- San Raffaele Scientific Institute, Milan, Italy.,Department of Neuroscience and Rehabilitation, Section of Pharmacology, University of Ferrara, Ferrara, Italy
| | - Pietro Marino
- Department of Neuroscience and Rehabilitation, Section of Pharmacology, University of Ferrara, Ferrara, Italy.,Department of Medical Sciences, Section of Pediatrics, University of Ferrara, Ferrara, Italy
| | - Michele Simonato
- Vita-Salute San Raffaele University, Milan, Italy.,San Raffaele Scientific Institute, Milan, Italy.,Department of Neuroscience and Rehabilitation, Section of Pharmacology, University of Ferrara, Ferrara, Italy
| | - Barbara Bettegazzi
- Vita-Salute San Raffaele University, Milan, Italy.,San Raffaele Scientific Institute, Milan, Italy
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3
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Clark CM, Clark RM, Hoyle JA, Dickson TC. Pathogenic or protective? Neuropeptide Y in amyotrophic lateral sclerosis. J Neurochem 2020; 156:273-289. [PMID: 32654149 DOI: 10.1111/jnc.15125] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2020] [Revised: 06/16/2020] [Accepted: 06/24/2020] [Indexed: 12/13/2022]
Abstract
Neuropeptide Y (NPY) is an endogenous peptide of the central and enteric nervous systems which has gained significant interest as a potential neuroprotective agent for treatment of neurodegenerative disease. Amyotrophic lateral sclerosis (ALS) is an aggressive and fatal neurodegenerative disease characterized by motor deficits and motor neuron loss. In ALS, recent evidence from ALS patients and animal models has indicated that NPY may have a role in the disease pathogenesis. Increased NPY levels were found to correlate with disease progression in ALS patients. Similarly, NPY expression is increased in the motor cortex of ALS mice by end stages of the disease. Although the functional consequence of increased NPY levels in ALS is currently unknown, NPY has been shown to exert a diverse range of neuroprotective roles in other neurodegenerative diseases; through modulation of potassium channel activity, increased production of neurotrophins, inhibition of endoplasmic reticulum stress and autophagy, reduction of excitotoxicity, oxidative stress, neuroinflammation and hyperexcitability. Several of these mechanisms and signalling pathways are heavily implicated in the pathogenesis of ALS. Therefore, in this review, we discuss possible effects of NPY and NPY-receptor signalling in the ALS disease context, as determining NPY's contribution to, or impact on, ALS disease mechanisms will be essential for future studies investigating the NPY system as a therapeutic strategy in this devastating disease.
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Affiliation(s)
- Courtney M Clark
- Menzies Institute for Medical Research, College of Health and Medicine, University of Tasmania, Hobart, TAS, Australia
| | - Rosemary M Clark
- Menzies Institute for Medical Research, College of Health and Medicine, University of Tasmania, Hobart, TAS, Australia
| | - Joshua A Hoyle
- Menzies Institute for Medical Research, College of Health and Medicine, University of Tasmania, Hobart, TAS, Australia
| | - Tracey C Dickson
- Menzies Institute for Medical Research, College of Health and Medicine, University of Tasmania, Hobart, TAS, Australia
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4
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Damasceno S, Gómez-Nieto R, Garcia-Cairasco N, Herrero-Turrión MJ, Marín F, Lopéz DE. Top Common Differentially Expressed Genes in the Epileptogenic Nucleus of Two Strains of Rodents Susceptible to Audiogenic Seizures: WAR and GASH/Sal. Front Neurol 2020; 11:33. [PMID: 32117006 PMCID: PMC7031349 DOI: 10.3389/fneur.2020.00033] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2019] [Accepted: 01/10/2020] [Indexed: 11/16/2022] Open
Abstract
The Wistar Audiogenic Rat (WAR) and the Genetic Audiogenic Seizure Hamster from Salamanca (GASH/Sal) strains are audiogenic epilepsy models, in which seizures are triggered by acoustic stimulation. These strains were developed by selective reproduction and have a genetic background with minimal or no variation. In the current study, we evaluated the transcriptome of the inferior colliculus, the epileptogenic nucleus, of both audiogenic models, in order to get insights into common molecular aspects associated to their epileptic phenotype. Based on GASH/Sal RNA-Seq and WAR microarray data, we performed a comparative analysis that includes selection and functional annotation of differentially regulated genes in each model, transcriptional evaluation by quantitative reverse transcription PCR of common genes identified in both transcriptomes and immunohistochemistry. The microarray data revealed 71 genes with differential expression in WAR, and the RNA-Seq data revealed 64 genes in GASH/Sal, showing common genes in both models. Analysis of transcripts showed that Egr3 was overexpressed in WAR and GASH/Sal after audiogenic seizures. The Npy, Rgs2, Ttr, and Abcb1a genes presented the same transcriptional profile in the WAR, being overexpressed in the naïve and stimulated WAR in relation to their controls. Npy appeared overexpressed only in the naïve GASH/Sal compared to its control, while Rgs2 and Ttr genes appeared overexpressed in naïve GASH/Sal and overexpressed after audiogenic seizure. No statistical difference was observed in the expression of Abcb1a in the GASH/Sal model. Compared to control animals, the immunohistochemical analysis of the inferior colliculus showed an increased immunoreactivity for NPY, RGS2, and TTR in both audiogenic models. Our data suggest that WAR and GASH/Sal strains have a difference in the timing of gene expression after seizure, in which GASH/Sal seems to respond more quickly. The transcriptional profile of the Npy, Rgs2, and Ttr genes under free-seizure conditions in both audiogenic models indicates an intrinsic expression already established in the strains. Our findings suggest that these genes may be causing small changes in different biological processes involved in seizure occurrence and response, and indirectly contributing to the susceptibility of the WAR and GASH/Sal models to audiogenic seizures.
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Affiliation(s)
- Samara Damasceno
- Institute of Neurosciences of Castilla y León, University of Salamanca, Salamanca, Spain
| | - Ricardo Gómez-Nieto
- Institute of Neurosciences of Castilla y León, University of Salamanca, Salamanca, Spain.,Salamanca Institute for Biomedical Research, Salamanca, Spain
| | | | - Manuel Javier Herrero-Turrión
- Institute of Neurosciences of Castilla y León, University of Salamanca, Salamanca, Spain.,INCYL Neurological Tissue Bank (BTN-INCYL), Salamanca, Spain
| | - Faustino Marín
- Department of Human Anatomy and Psychobiology, School of Medicine, University of Murcia, Murcia, Spain
| | - Dolores E Lopéz
- Institute of Neurosciences of Castilla y León, University of Salamanca, Salamanca, Spain.,Salamanca Institute for Biomedical Research, Salamanca, Spain
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5
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Tulke S, Haas CA, Häussler U. Expression of brain‐derived neurotrophic factor and structural plasticity in the dentate gyrus and
CA
2 region correlate with epileptiform activity. Epilepsia 2019; 60:1234-1247. [DOI: 10.1111/epi.15540] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2018] [Revised: 04/17/2019] [Accepted: 04/22/2019] [Indexed: 01/29/2023]
Affiliation(s)
- Susanne Tulke
- Experimental Epilepsy Research Department of Neurosurgery Medical Center - University of Freiburg Faculty of Medicine University of Freiburg Freiburg im Breisgau Germany
- Faculty of Biology University of Freiburg Freiburg im Breisgau Germany
| | - Carola A. Haas
- Experimental Epilepsy Research Department of Neurosurgery Medical Center - University of Freiburg Faculty of Medicine University of Freiburg Freiburg im Breisgau Germany
- BrainLinks‐BrainTools Cluster of Excellence University of Freiburg Freiburg im Breisgau Germany
| | - Ute Häussler
- Experimental Epilepsy Research Department of Neurosurgery Medical Center - University of Freiburg Faculty of Medicine University of Freiburg Freiburg im Breisgau Germany
- BrainLinks‐BrainTools Cluster of Excellence University of Freiburg Freiburg im Breisgau Germany
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6
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Domin H, Przykaza Ł, Jantas D, Kozniewska E, Boguszewski PM, Śmiałowska M. Neuropeptide Y Y2 and Y5 receptors as promising targets for neuroprotection in primary neurons exposed to oxygen-glucose deprivation and in transient focal cerebral ischemia in rats. Neuroscience 2017; 344:305-325. [PMID: 28057538 DOI: 10.1016/j.neuroscience.2016.12.040] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2016] [Revised: 12/21/2016] [Accepted: 12/22/2016] [Indexed: 01/08/2023]
Abstract
It was postulated that neuropeptide Y (NPY)-ergic system could be involved in the ischemic pathophysiology, however, the role of particular subtypes of NPY receptors (YRs) in neuroprotection against ischemia is still not well known. Therefore, we investigated the effect of NPY and YR ligands using in vitro and in vivo experimental ischemic stroke models. Our in vitro findings showed that NPY (0.5-1μM) and specific agonists of Y2R (0.1-1μM) and Y5R (0.5-1μM) but not that of Y1R produced neuroprotective effects against oxygen-glucose deprivation (OGD)-induced neuronal cell death, being also effective when given 30min after the end of OGD. The neuroprotective effects of Y2R and Y5R agonists were reversed by appropriate antagonists. Neuroprotection mediated by NPY, Y2R and Y5R agonists was accompanied by the inhibition of both OGD-induced calpain activation and glutamate release. Data from in vivo studies demonstrated that Y2R agonist (10μg/6μl; i.c.v.) not only diminished the infarct volume in rats subjected to transient middle cerebral artery occlusion (MCAO) but also improved selected gait parameters in CatWalk behavioral test, being also effective after delayed treatment. Moreover, we found that a Y5R agonist (10μg/6μl; i.c.v.) did not reduce MCAO-evoked brain damage but improved stride length, when it was given 30min after starting the occlusion. In conclusion, our studies indicate that Y5 and especially Y2 receptors may be promising targets for neuroprotection against ischemic damage.
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Affiliation(s)
- Helena Domin
- Institute of Pharmacology, Polish Academy of Sciences, Department of Neurobiology, 31-343 Kraków, Smętna Street 12, Poland.
| | - Łukasz Przykaza
- Mossakowski Medical Research Centre, Polish Academy of Sciences, Department of Neurosurgery, Laboratory of Experimental Neurosurgery, Pawińskiego Street 5, 02-106 Warsaw, Poland
| | - Danuta Jantas
- Institute of Pharmacology, Polish Academy of Sciences, Department of Experimental Neuroendocrinology, 31-343 Kraków, Smętna Street 12, Poland
| | - Ewa Kozniewska
- Mossakowski Medical Research Centre, Polish Academy of Sciences, Department of Neurosurgery, Laboratory of Experimental Neurosurgery, Pawińskiego Street 5, 02-106 Warsaw, Poland; Medical University of Warsaw, Department of Experimental and Clinical Physiology, Pawińskiego Street 3C, 02-106 Warsaw, Poland
| | - Paweł M Boguszewski
- Laboratory of Animal Models, Neurobiology Centre, Nencki Institute of Experimental Biology of Polish Academy of Sciences, 3 Pasteur Str., 02-093 Warsaw, Poland
| | - Maria Śmiałowska
- Institute of Pharmacology, Polish Academy of Sciences, Department of Neurobiology, 31-343 Kraków, Smętna Street 12, Poland
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7
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Ramírez-Franco JJ, Munoz-Cuevas FJ, Luján R, Jurado S. Excitatory and Inhibitory Neurons in the Hippocampus Exhibit Molecularly Distinct Large Dense Core Vesicles. Front Cell Neurosci 2016; 10:202. [PMID: 27630542 PMCID: PMC5005380 DOI: 10.3389/fncel.2016.00202] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2016] [Accepted: 08/05/2016] [Indexed: 12/21/2022] Open
Abstract
Hippocampal interneurons comprise a diverse family of inhibitory neurons that are critical for detailed information processing. Along with gamma-aminobutyric acid (GABA), interneurons secrete a myriad of neuroactive substances via secretory vesicles but the molecular composition and regulatory mechanisms remain largely unknown. In this study, we have carried out an immunohistofluorescence analysis to describe the molecular content of vesicles in distinct populations of hippocampal neurons. Our results indicate that phogrin, an integral protein of secretory vesicles in neuroendocrine cells, is highly enriched in parvalbumin-positive interneurons. Consistently, immunoelectron microscopy revealed phogrin staining in axon terminals of symmetrical synapses establishing inhibitory contacts with cell bodies of CA1 pyramidal neurons. Furthermore, phogrin is highly expressed in CA3 and dentate gyrus (DG) interneurons which are both positive for PV and neuropeptide Y. Surprisingly, chromogranin B a canonical large dense core vesicle marker, is excluded from inhibitory cells in the hippocampus but highly expressed in excitatory CA3 pyramidal neurons and DG granule cells. Our results provide the first evidence of phogrin expression in hippocampal interneurons and suggest the existence of molecularly distinct populations of secretory vesicles in different types of inhibitory neurons.
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Affiliation(s)
| | | | - Rafael Luján
- Synaptic Structure Laboratory, Departamento de Ciencias Médicas, Facultad de Medicina, Instituto de Investigación en Discapacidades Neurológicas, Universidad Castilla-La ManchaAlbacete, Spain
| | - Sandra Jurado
- Department of Pharmacology, University of Maryland School of MedicineBaltimore, MD, USA
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8
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Neuropeptide FF receptors as novel targets for limbic seizure attenuation. Neuropharmacology 2015; 95:415-23. [DOI: 10.1016/j.neuropharm.2015.04.030] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2014] [Revised: 04/23/2015] [Accepted: 04/26/2015] [Indexed: 01/08/2023]
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9
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Expression of neuropeptide Y1 receptors in the amygdala and hippocampus and anxiety-like behavior associated with Ammon's horn sclerosis following intrahippocampal kainate injection in C57BL/6J mice. Epilepsy Behav 2014; 37:175-83. [PMID: 25050777 DOI: 10.1016/j.yebeh.2014.06.033] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/09/2014] [Revised: 06/24/2014] [Accepted: 06/26/2014] [Indexed: 11/22/2022]
Abstract
Damage to the amygdala is often linked to Ammon's horn sclerosis (AHS) in surgical specimens of patients suffering from temporal lobe epilepsy (TLE). Moreover, amygdalar pathology is thought to contribute to the development of anxiety symptoms frequently found in TLE. The neuropeptide Y (NPY) Y1 receptor is critical in the regulation of anxiety-related behavior and epileptiform activity in TLE. Therefore, intrahippocampal kainate (KA) injection was performed to induce AHS-associated TLE and to investigate behavioral and cytoarchitectural changes that occur in the amygdala related to Y1 receptor expression. Status epilepticus was induced by intrahippocampal KA injection in C57BL/6J mice. Anxiety-like behavior was assessed using the elevated plus maze (EPM). Pathology of hippocampus and amygdala (volume loss and gliosis) was examined in KA-injected and saline-injected controls. Y1 receptor expression was measured using immunohistochemistry and ELISA. Animal injected with KA showed increased anxiety-like behaviors and reduced risk assessment in the EPM test compared with saline-injected controls. In the ipsilateral hippocampus of KA-injected animals, CA1 ablation, granule cell dispersion, and volume reduction were accompanied by astrogliosis indicating the development of AHS. In the amygdala, a significant decrease in the volume of nuclei and numbers of neurons was observed in the ipsilateral lateral, basolateral, and central amygdalar nuclei, which was accompanied by astrogliosis. In addition, a decrease in Y1 receptor-expressing cells in the ipsilateral CA1 and CA3 sectors of the hippocampus, ipsilateral and contralateral granule cell layer of the dentate gyrus, and ipsilateral central nucleus of the amygdala was found, consistent with a reduction in Y1 receptor protein levels. Our results suggest that plastic changes in hippocampal and/or amygdalar Y1 receptor expression may negatively impact anxiety levels. Moreover, intrahippocampal KA injection can induce amygdalar damage suggesting that AHS-associated amygdala damage may contribute to behavioral alterations seen in patients with TLE.
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10
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Ghahramanian Golzar M, Babri S, Ataie Z, Ebrahimi H, Mirzaie F, Mohaddes G. NPY Receptors Blockade Prevents Anticonvulsant Action of Ghrelin in the Hippocampus of Rat. Adv Pharm Bull 2013; 3:265-71. [PMID: 24312846 DOI: 10.5681/apb.2013.043] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2012] [Revised: 01/10/2013] [Accepted: 01/13/2013] [Indexed: 01/13/2023] Open
Abstract
PURPOSE Ghrelin has been shown to have antiepileptic function. However, the underlying mechanisms by which, ghrelin exerts its antiepileptic effects are still unclear. In the present study, we investigated whether neuropeptide Y (NPY) mediates ghrelin anticonvulsant effect in the brain through its Y1, Y2 or Y5 receptors. METHODS Male Wistar rats were bilaterally microinjected with ghrelin 0.3 nmol/μl/side and NPY antagonists; GR231118 (Y1 receptor antagonist), BIIE0246 (Y2 receptor antagonist), CGP71683 (Y5 receptor antagonist) or solvents (Saline, DMSO) into the dorsal hippocampus 20 minutes before ghrelin administration. Thirty minutes after ghrelin microinjection, a single convulsive dose of pentylenetetrazole (PTZ) (50 mg/kg) was injected intraperitoneally (ip). Afterwards, duration of seizure and total seizure score (TSS) were assessed for 30 minutes in all animals. RESULTS Intrahippocampal injection of 0.3 nmol/μl/side ghrelin decreased duration of seizure and TSS induced by PTZ. The suppression of both duration (p<0.001) and TSS (p<0.001) induced by ghrelin in hippocampus were significantly blocked by GR231118 (10 μg/μl/side), BIIE0246 (400 pmol/μl/side) and CGP 71683A (5 nmol/μl/side). CONCLUSION Our findings suggest that NPY Y1, Y2 and Y5 receptors in the hippocampus may somehow mediate the anticonvulsive action of ghrelin. Therefore, it is possible to speculate that ghrelin acts in the hippocampus to modulate seizures via NPY.
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11
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Neuropeptide Y increases in vivo hippocampal extracellular glutamate levels through Y1 receptor activation. Neurosci Lett 2012; 510:143-7. [DOI: 10.1016/j.neulet.2012.01.023] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2011] [Revised: 12/20/2011] [Accepted: 01/09/2012] [Indexed: 01/19/2023]
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12
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Lukasiuk K, Pitkänen A. Molecular basis of acquired epileptogenesis. HANDBOOK OF CLINICAL NEUROLOGY 2012; 107:3-12. [DOI: 10.1016/b978-0-444-52898-8.00001-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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13
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Olesen MV, Christiansen SH, Gøtzsche CR, Nikitidou L, Kokaia M, Woldbye DPD. Neuropeptide Y Y1 receptor hippocampal overexpression via viral vectors is associated with modest anxiolytic-like and proconvulsant effects in mice. J Neurosci Res 2011; 90:498-507. [PMID: 21971867 DOI: 10.1002/jnr.22770] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2011] [Revised: 07/15/2011] [Accepted: 07/24/2011] [Indexed: 02/06/2023]
Abstract
Neuropeptide Y (NPY) exerts anxiolytic- and antidepressant-like effects in rodents that appear to be mediated via Y1 receptors. Gene therapy using recombinant viral vectors to induce overexpression of NPY in the hippocampus or amygdala has previously been shown to confer anxiolytic-like effect in rodents. The present study explored an alternative and more specific approach: overexpression of Y1 receptors. Using a recombinant adeno-associated viral vector (rAAV) encoding the Y1 gene (rAAV-Y1), we, for the first time, induced overexpression of functional transgene Y1 receptors in the hippocampus of adult mice and tested the animals in anxiety- and depression-like behavior. Hippocampal Y1 receptors have been suggested to mediate seizure-promoting effect, so the effects of rAAV-induced Y1 receptor overexpression were also tested in kainate-induced seizures. Y1 receptor transgene overexpression was found to be associated with modest anxiolytic-like effect in the open field and elevated plus maze tests, but no effect was seen on depression-like behavior using the tail suspension and forced swim tests. However, the rAAV-Y1 vector modestly aggravated kainate-induced seizures. These data indicate that rAAV-induced overexpression of Y1 receptors in the hippocampus could confer anxiolytic-like effect accompanied by a moderate proconvulsant adverse effect. Further studies are clearly needed to determine whether Y1 gene therapy might have a future role in the treatment of anxiety disorders.
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Affiliation(s)
- M V Olesen
- Laboratory of Neuropsychiatry, Psychiatric Centre Copenhagen and Protein Laboratory, Department of Neuroscience and Pharmacology, University of Copenhagen, Copenhagen, Denmark
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14
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Woldbye DPD, Angehagen M, Gøtzsche CR, Elbrønd-Bek H, Sørensen AT, Christiansen SH, Olesen MV, Nikitidou L, Hansen TVO, Kanter-Schlifke I, Kokaia M. Adeno-associated viral vector-induced overexpression of neuropeptide Y Y2 receptors in the hippocampus suppresses seizures. ACTA ACUST UNITED AC 2010; 133:2778-88. [PMID: 20688813 DOI: 10.1093/brain/awq219] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Gene therapy using recombinant adeno-associated viral vectors overexpressing neuropeptide Y in the hippocampus exerts seizure-suppressant effects in rodent epilepsy models and is currently considered for clinical application in patients with intractable mesial temporal lobe epilepsy. Seizure suppression by neuropeptide Y in the hippocampus is predominantly mediated by Y2 receptors, which, together with neuropeptide Y, are upregulated after seizures as a compensatory mechanism. To explore whether such upregulation could prevent seizures, we overexpressed Y2 receptors in the hippocampus using recombinant adeno-associated viral vectors. In two temporal lobe epilepsy models, electrical kindling and kainate-induced seizures, vector-based transduction of Y2 receptor complementary DNA in the hippocampus of adult rats exerted seizure-suppressant effects. Simultaneous overexpression of Y2 and neuropeptide Y had a more pronounced seizure-suppressant effect. These results demonstrate that overexpression of Y2 receptors (alone or in combination with neuropeptide Y) could be an alternative strategy for epilepsy treatment.
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Affiliation(s)
- David P D Woldbye
- Experimental Epilepsy Group, Wallenberg Neuroscience Center, Lund University Hospital, Lund, Sweden
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15
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Lin EJD, Lin S, Aljanova A, During MJ, Herzog H. Adult-onset hippocampal-specific neuropeptide Y overexpression confers mild anxiolytic effect in mice. Eur Neuropsychopharmacol 2010; 20:164-75. [PMID: 19781916 DOI: 10.1016/j.euroneuro.2009.08.004] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/01/2009] [Revised: 07/09/2009] [Accepted: 08/18/2009] [Indexed: 01/29/2023]
Abstract
The anticonvulsive properties of neuropeptide Y (NPY) are opening up opportunity for the development of NPY gene transfer as a therapy for epilepsy. In order to pursue the potential clinical translation of this approach, the effects of somatic NPY gene transfer on other hippocampal functions need to be assessed. The present study characterized the behavioral effects of recombinant adeno-associated viral vector (rAAV)-mediated hippocampal NPY overexpression in adult male mice and also Y1 receptor knockout mice. In wild-type mice, there were no obvious adverse effects on the general health, motor function and cognition following rAAV-NPY treatment. Moreover, hippocampal NPY overexpression induced a moderate anxiolytic effect in the open field test and elevated plus maze. Intriguingly, the treatment also increased depressive-like behavior in the tail suspension test. Elevated hippocampal NPY levels in the absence of Y1 signalling had no effects on anxiety or cognition and actually improved the depressive-like phenotype observed in the wild-type mice treated with rAAV-NPY.
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Affiliation(s)
- En-Ju Deborah Lin
- Neurobiology Program, Garvan Institute of Medical Research, Sydney, Australia.
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16
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Smiałowska M, Domin H, Zieba B, Koźniewska E, Michalik R, Piotrowski P, Kajta M. Neuroprotective effects of neuropeptide Y-Y2 and Y5 receptor agonists in vitro and in vivo. Neuropeptides 2009; 43:235-49. [PMID: 19318226 DOI: 10.1016/j.npep.2009.02.002] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/03/2008] [Revised: 02/12/2009] [Accepted: 02/13/2009] [Indexed: 11/15/2022]
Abstract
It is generally assumed that neurodegeneration is connected with glutamatergic hyperactivity, and that neuropeptide Y (NPY) inhibits glutamate release. Some earlier studies indicated that NPY may have neuroprotective effect; however, the results obtained so far are still divergent, and the role of different Y receptors remains unclear. Therefore in the presented study we investigated the neuroprotective potential of NPY and its Y2, Y5 or Y1 receptor (R) ligands against the kainate (KA)-induced excitotoxicity in neuronal cultures in vitro, as well as in vivo after intrahippocampal KA injection and also in an ischemic middle cerebral artery occlusion model after intraventricular injection of Y2R agonist. NPY compounds were applicated 30 min, 1, 3 or 6 h after the start of the exposure to KA, or 30 min after the onset of ischemia. Our results indicate the neuroprotective activity of NPY and its Y2R and Y5R ligands against the kainate-induced excitotoxicity in primary cortical and hippocampal cultures. Importantly, NPY was effective when given as late as 6 h, while Y2R or Y5R agonists 3 h, after starting the exposure to KA. In in vitro studies those protective effects were inhibited by the respective receptor antagonists. Neuroprotection was also observed in vivo after intrahippocampal injection of Y2R and Y5R agonists 30 min or 1 h after KA. No protection was found either in vitro or in vivo after the Y1R agonist. The Y2R agonist also showed neuroprotective activity in the ischemic model. The obtained results indicate that neuropeptide Y produces neuroprotective effect via Y2 and Y5 receptors, and that the compounds may be effective after delayed application.
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Affiliation(s)
- Maria Smiałowska
- Department of Neurobiology, Institute of Pharmacology, Polish Academy of Sciences, Smetna 12, 31-343 Kraków, Poland.
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Noè F, Pool AH, Nissinen J, Gobbi M, Bland R, Rizzi M, Balducci C, Ferraguti F, Sperk G, During MJ, Pitkänen A, Vezzani A. Neuropeptide Y gene therapy decreases chronic spontaneous seizures in a rat model of temporal lobe epilepsy. Brain 2008; 131:1506-15. [DOI: 10.1093/brain/awn079] [Citation(s) in RCA: 133] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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18
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Palop JJ, Chin J, Roberson ED, Wang J, Thwin MT, Bien-Ly N, Yoo J, Ho KO, Yu GQ, Kreitzer A, Finkbeiner S, Noebels JL, Mucke L. Aberrant excitatory neuronal activity and compensatory remodeling of inhibitory hippocampal circuits in mouse models of Alzheimer's disease. Neuron 2007; 55:697-711. [PMID: 17785178 PMCID: PMC8055171 DOI: 10.1016/j.neuron.2007.07.025] [Citation(s) in RCA: 1184] [Impact Index Per Article: 69.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2006] [Revised: 05/11/2007] [Accepted: 07/18/2007] [Indexed: 11/27/2022]
Abstract
Neural network dysfunction may play an important role in Alzheimer's disease (AD). Neuronal circuits vulnerable to AD are also affected in human amyloid precursor protein (hAPP) transgenic mice. hAPP mice with high levels of amyloid-beta peptides in the brain develop AD-like abnormalities, including cognitive deficits and depletions of calcium-related proteins in the dentate gyrus, a region critically involved in learning and memory. Here, we report that hAPP mice have spontaneous nonconvulsive seizure activity in cortical and hippocampal networks, which is associated with GABAergic sprouting, enhanced synaptic inhibition, and synaptic plasticity deficits in the dentate gyrus. Many Abeta-induced neuronal alterations could be simulated in nontransgenic mice by excitotoxin challenge and prevented in hAPP mice by blocking overexcitation. Aberrant increases in network excitability and compensatory inhibitory mechanisms in the hippocampus may contribute to Abeta-induced neurological deficits in hAPP mice and, possibly, also in humans with AD.
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Affiliation(s)
- Jorge J. Palop
- Gladstone Institute of Neurological Disease, San Francisco, CA 94158, USA
- Department of Neurology, University of California, San Francisco, San Francisco, CA 94158, USA
- Correspondence: or
| | - Jeannie Chin
- Gladstone Institute of Neurological Disease, San Francisco, CA 94158, USA
- Department of Neurology, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Erik D. Roberson
- Gladstone Institute of Neurological Disease, San Francisco, CA 94158, USA
- Department of Neurology, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Jun Wang
- Gladstone Institute of Neurological Disease, San Francisco, CA 94158, USA
| | - Myo T. Thwin
- Gladstone Institute of Neurological Disease, San Francisco, CA 94158, USA
| | - Nga Bien-Ly
- Gladstone Institute of Neurological Disease, San Francisco, CA 94158, USA
| | - Jong Yoo
- Developmental Neurogenetics Laboratory, Department of Neurology, Baylor College of Medicine, Houston, TX 77030, USA
| | - Kaitlyn O. Ho
- Gladstone Institute of Neurological Disease, San Francisco, CA 94158, USA
| | - Gui-Qiu Yu
- Gladstone Institute of Neurological Disease, San Francisco, CA 94158, USA
| | - Anatol Kreitzer
- Gladstone Institute of Neurological Disease, San Francisco, CA 94158, USA
- Department of Physiology, University of California, San Francisco, San Francisco, CA 94158, USA
- Neuroscience Graduate Program, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Steven Finkbeiner
- Gladstone Institute of Neurological Disease, San Francisco, CA 94158, USA
- Department of Neurology, University of California, San Francisco, San Francisco, CA 94158, USA
- Department of Physiology, University of California, San Francisco, San Francisco, CA 94158, USA
- Neuroscience Graduate Program, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Jeffrey L. Noebels
- Developmental Neurogenetics Laboratory, Department of Neurology, Baylor College of Medicine, Houston, TX 77030, USA
| | - Lennart Mucke
- Gladstone Institute of Neurological Disease, San Francisco, CA 94158, USA
- Department of Neurology, University of California, San Francisco, San Francisco, CA 94158, USA
- Neuroscience Graduate Program, University of California, San Francisco, San Francisco, CA 94158, USA
- Correspondence: or
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Xapelli S, Silva AP, Ferreira R, Malva JO. Neuropeptide Y can rescue neurons from cell death following the application of an excitotoxic insult with kainate in rat organotypic hippocampal slice cultures. Peptides 2007; 28:288-94. [PMID: 17212973 DOI: 10.1016/j.peptides.2006.09.031] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/08/2006] [Accepted: 09/22/2006] [Indexed: 10/23/2022]
Abstract
In the present work we investigated the neuroprotective role of neuropeptide Y (NPY) after an excitotoxic insult in rat organotypic hippocampal slice cultures. Exposure of 2 week-old rat hippocampal slice cultures to 12muM kainate (KA) for 24h induced neuronal death in dentate gyrus (DG) granular cell layer, CA1 and CA3 pyramidal cell layers, as quantified by cellular propidium iodide (PI) uptake. The activation of Y(1) or Y(2) receptors 30min after starting the exposure to the excitotoxic insult with kainate resulted in neuroprotection by reducing the PI uptake in DG, CA1 and CA3 cell layers. The use of Y(1) or Y(2) receptors antagonists, BIBP3226 (1muM) or BIIE0246 (1muM), resulted in the loss of the neuroprotection induced by the activation of Y(1) or Y(2) receptors, respectively, in all hippocampal subfields. Taken together these results suggest that activation of NPY Y(1) or Y(2) receptors activates neuroprotective pathways that are able to rescue neurons from excitotoxic cell death.
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Affiliation(s)
- S Xapelli
- Center for Neuroscience and Cell Biology of Coimbra, 3004-517 Coimbra, Portugal
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20
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Abstract
Neuropeptide Y (NPY) is contained in at least four types of GABAergic interneurons in the dentate gyrus, many of which also contain somatostatin and give rise to the dense NPY innervation of the dentate outer molecular layer. In humans but not rats, minute amounts of NPY are also normally expressed in dentate granule cells, while seizure activity in rats induces robust NPY expression in granule cells. Y1 and Y2 receptors are the most abundant NPY receptors expressed in the dentate gyrus. Y1 receptors are postsynaptic receptors, primarily located on granule cell dendrites in the molecular layer and some interneurons, while Y2 receptors are presynaptic receptors mediating inhibition of glutamate release, and potentially that of NPY and GABA depending on their presynaptic localization, and may also be expressed on some hilar interneurons. In humans, monkeys and mice, Y2 receptors are also present on mossy fibers, but not in most rat species, though functional evidence suggests their presence. Hilar interneurons containing NPY degenerate in temporal lobe epilepsy and in Alzheimer's disease and reduced levels of NPY in dentate hilus are associated with depression. By activating Y1 receptors, NPY also exerts powerful neuroproliferative effects on subgranular zone progenitor cells, increasing the number of newly born granule cells in the adult dentate gyrus. Functionally, NPY exerts anticonvulsive actions mediated by Y2 receptors at mossy fiber terminals, but there are no presynaptic responses to NPY at perforant path inputs to dentate granule cells in rats or mice. NPY also has potentially complicated actions on NPY-containing interneurons. Elevated expression of NPY in mossy fibers of the rat, sprouting of NPY interneurons in the human dentate, and over-expression of Y2 receptors in mossy fibers indicate an anticonvulsive role of endogenous NPY in epilepsy. However, the physiological role of NPY in the healthy dentate gyrus remains unclear.
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Affiliation(s)
- Günther Sperk
- Department of Pharmacology, Medical University Innsbruck, Peter-Mayr-Str. 1a, 6020 Innsbruck, Austria.
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21
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Kokaia M, Lundberg C. Neuropeptide gene therapy for epilepsy: viral vectors, stem cells and neurogenesis. FUTURE NEUROLOGY 2006. [DOI: 10.2217/14796708.1.6.843] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Gene therapy for epilepsy is a relatively novel concept compared with previous approaches, which have relied on primary embryonic cells to deliver gene products of interest into localized brain regions. In vivo and ex vivo gene transfer offer promising, but yet insufficiently explored, possibilities to inhibit seizures, either by genetically modifying postmitotic neurons of the brain using viral vectors, or by transplanting genetically modified and in vitro tested cell lines, particularly stem cell lines, to produce and release gene products of interest. In this regard, neuropeptides are discussed as emerging candidates for such gene therapy approaches. Selective modification of newly generated neurons in the dentate gyrus by retroviral vector-based gene delivery opens novel possibilities in gene therapy for epilepsy. However, the limited number of new neurons targeted remains a main obstacle. Despite its early stage, gene therapy for epilepsy might not be a remote prospect for clinical trials, particularly in patients with intractable temporal lobe epilepsy. Ex vivo gene transfer using encapsulated genetically modified cells could be of particular value for such initial trials.
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Affiliation(s)
- Merab Kokaia
- Wallenberg Neuroscience Center, Experimental Epilepsy Group, Lund University Hospital, 221 84 Lund, Sweden
| | - Cecilia Lundberg
- Wallenberg Neuroscience Center, CNS Gene Therapy Group, Lund University Hospital, 221 84 Lund, Sweden
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22
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Eva C, Serra M, Mele P, Panzica G, Oberto A. Physiology and gene regulation of the brain NPY Y1 receptor. Front Neuroendocrinol 2006; 27:308-39. [PMID: 16989896 DOI: 10.1016/j.yfrne.2006.07.002] [Citation(s) in RCA: 101] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/29/2005] [Revised: 07/18/2006] [Accepted: 07/25/2006] [Indexed: 10/24/2022]
Abstract
Neuropeptide Y (NPY) is one of the most prominent and abundant neuropeptides in the mammalian brain where it interacts with a family of G-protein coupled receptors, including the Y(1) receptor subtype (Y(1)R). NPY-Y(1)R signalling plays a prominent role in the regulation of several behavioural and physiological functions including feeding behaviour and energy balance, sexual hormone secretion, stress response, emotional behaviour, neuronal excitability and ethanol drinking. Y(1)R expression is regulated by neuronal activity and peripheral hormones. The Y(1)R gene has been isolated from rodents and humans and it contains multiple regulatory elements that may participate in the regulation of its expression. Y(1)R expression in the hypothalamus is modulated by changes in energetic balance induced by a wide variety of conditions (fasting, pregnancy, hyperglycaemic challenge, hypophagia, diet induced obesity). Estrogens up-regulate responsiveness to NPY to stimulate preovulatory GnRH and gonadotropin surges by increasing Y(1)R gene expression both in the hypothalamus and the pituitary. Y(1)R expression is modulated by different kinds of brain insults, such as stress and seizure activity, and alteration in its expression may contribute to antidepressant action. Chronic modulation of GABA(A) receptor function by benzodiazepines or neuroactive steroids also affects Y(1)R expression in the amygdala, suggesting that a functional interaction between the GABA(A) receptor and Y(1)R mediated signalling may contribute to the regulation of emotional behaviour. In this paper, we review the state of the art concerning Y(1)R function and gene expression, including our personal contribution to many of the subjects mentioned above.
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Affiliation(s)
- Carola Eva
- Sezione di Farmacologia, Dipartimento di Anatomia, Farmacologia e Medicina Legale, Università di Torino, Italy; Centro Rita Levi Montalcini, Università di Torino, Italy.
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23
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Eva C, Oberto A, Mele P, Serra M, Biggio G. Role of brain neuroactive steroids in the functional interplay between the GABA(A) and the NPY-Y1 receptor mediated signals in the amygdala. Pharmacol Biochem Behav 2006; 84:568-80. [PMID: 16824587 DOI: 10.1016/j.pbb.2006.05.014] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/03/2006] [Accepted: 05/17/2006] [Indexed: 11/18/2022]
Abstract
Various lines of evidence suggest a functional interaction between GABA(A) and Neuropeptide Y (NPY)-Y(1) receptor (Y(1)R) mediated transmissions in various brain regions, which can be important in the regulation of sedation, feeding, anxious behaviour and neuronal excitability. By using a transgenic mouse model carrying the murine Y(1)R gene promoter fused to the lacZ reporter gene (Y(1)R/LacZ mice), we showed that prolonged pharmacologically or physiologically induced changes in the cerebrocortical concentrations of the neuroactive steroids 3alpha-hydroxy-5alpha-pregnan- 20-one (3alpha,5alpha TH PROG) and tetrahydrodeoxycorticosterone (3alpha,5alpha TH DOC) increases Y(1)R/LacZ transgene expression in the central and medial amygdala, an effect similar to that induced by long-term treatment with positive modulators of the GABA(A) receptor complex (diazepam or abecarnil). We also demonstrated that fluctuations in the cerebrocortical concentrations of 3alpha,5alpha-TH PROG and 3alpha,5alpha TH DOC during voluntary ethanol consumption and ethanol withdrawal induces a marked increase in Y(1)R gene expression that becomes apparent 48 h after withdrawal. These data provide evidence that neuroactive steroids may play an important role in the functional interaction between the GABA(A) receptor and NPY-Y(1)R mediated pathways in the amygdala, which might represent an important regulatory mechanism for modulation of several functions, including ethanol withdrawal.
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Affiliation(s)
- Carola Eva
- Dipartimento di Anatomia, Farmacologia e Medicina Legale, Sezione di Farmacologia, Via Pietro Giuria 13, 10125, Università di Torino, Torino, Italy.
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24
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Lin EJD, Young D, Baer K, Herzog H, During MJ. Differential actions of NPY on seizure modulation via Y1 and Y2 receptors: evidence from receptor knockout mice. Epilepsia 2006; 47:773-80. [PMID: 16650144 DOI: 10.1111/j.1528-1167.2006.00500.x] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
PURPOSE Neuropeptide Y (NPY) has been shown to modulate seizure activities. To provide further understanding of the involvement of two of the most abundantly expressed NPY receptors, Y1 and Y2, we assessed the effect of Y1 and Y2 gene deletion on systemic kainic acid-induced seizures. We also examined the effect of rAAV-mediated hippocampal NPY overexpression on seizure susceptibility in these receptor knockout mice. METHODS Recombinant adeno-associated viral vector overexpressing NPY (rAAV-NPY) or an empty vector control (rAAV-Empty) was injected into the hippocampus of adult C57BL/6-129/SvJ wild-type male mice and mice deficient of Y1 or Y2 receptors on the same background. Four weeks after vector injection, mice were subjected to systemic kainic acid-induced seizures, and the seizure behaviors were scored. RESULTS The rAAV-mediated hippocampal overexpression of NPY led to a twofold reduction in seizures induced by systemic kainic acid in wild-type mice and Y1 receptor knockout mice but not in mice deficient of Y2 receptors. A differential action by the receptors was observed in the seizure-induced mortality rate, with increased fatality in Y2-/- mice. In addition, although NPY overexpression did not significantly affect the mortality rate in Y2-/- and wild-type mice, it abolished KA-induced mortality in Y1-/-mice. CONCLUSIONS This study shows for the first time an altered susceptibility to chemically induced seizures in Y1 and Y2 knockout mice and demonstrates a differential seizure modulation mediated by these receptors via a genetic approach.
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Affiliation(s)
- En-Ju Deborah Lin
- Department of Molecular Medicine and Pathology, University of Auckland, Auckland, New Zealand.
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25
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Scharfman HE, Gray WP. Plasticity of neuropeptide Y in the dentate gyrus after seizures, and its relevance to seizure-induced neurogenesis. EXS 2006:193-211. [PMID: 16383008 PMCID: PMC4398306 DOI: 10.1007/3-7643-7417-9_15] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
In summary, NPY is clearly an important peptide in the adult rat dentate gyrus because it has the potential to influence synaptic transmission and neurogenesis. It may even have other functions, as yet undiscovered, mediated by glia or vasculature. The remarkable plasticity of NPY puts it in a position to allow dentate gyrus function to be modified in a changing environment. The importance of this plasticity in the context of epilepsy cannot be emphasized enough. It could help explain a range of observations about epilepsy that currently is poorly understood. For example, rapid increases in NPY could mediate postictal depression, the period of depression that can last for several hours after generalized seizures. It may mediate the "priming effect," which is a reduction in seizure threshold following an initial period of seizures. Finally, it could contribute to the resistance of dentate granule cells to degeneration after seizures. However, despite the focus in this review on seizure-induced changes, the changes described here also appear to occur after other types of manipulations, which considerably broadens the scope of NPY's role in the brain.
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Affiliation(s)
- Helen E Scharfman
- Departments of Pharmacology and Neurology, Columbia University, New York, USA.
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26
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Csaba Z, Pirker S, Lelouvier B, Simon A, Videau C, Epelbaum J, Czech T, Baumgartner C, Sperk G, Dournaud P. Somatostatin receptor type 2 undergoes plastic changes in the human epileptic dentate gyrus. J Neuropathol Exp Neurol 2005; 64:956-69. [PMID: 16254490 DOI: 10.1097/01.jnen.0000186923.50215.50] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Temporal lobe epilepsy (TLE) is characterized by hippocampal sclerosis together with profound losses and phenotypic changes of different classes of interneurons, including those expressing somatostatin (SRIF). To understand the functional significance of the plasticity of SRIF transmission in TLE, unraveling the status of SRIF receptors is, however, a prerequisite. To address this issue, we characterized expression and distribution of the major SRIF receptor, the sst2 subtype, in hippocampal tissue resected in patients with TLE using complementary neuroanatomic approaches. In patients with hippocampal sclerosis, the number of cells expressing sst2 receptor mRNA as well as sst2 receptor-binding sites and immunoreactivity decreased significantly in the CA1-3, reflecting neuronal loss. By contrast, in the dentate gyrus, sst2 receptor mRNA expression was strongly increased in the granule cell layer, and sst2 receptor-binding sites and immunoreactivity was preserved in the inner but decreased significantly in the outer molecular layer. In this latter region, pronounced changes in SRIF terminal fields were observed. Decreased receptor density in the distal dendrites of granule cells is likely to reflect downregulation of sst2 receptors in response to physiopathologic release of SRIF. Because sst2 receptors have anticonvulsant and antiepileptogenic properties, this phenomenon may contribute to the etiology of TLE seizures.
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Affiliation(s)
- Zsolt Csaba
- Neuroendocrine Research Laboratory, Hungarian Academy of Sciences and Department of Human Morphology and Developmental Biology, Semmelweis University, Budapest
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27
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Zhang LP, Wang L. Changes of brain neuropeptide Y and its receptors in rats with flurazepam tolerance and dependence. Acta Pharmacol Sin 2005; 26:1290-6. [PMID: 16225749 DOI: 10.1111/j.1745-7254.2005.00179.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
AIM Anticonvulsant tolerance and dependence are two obstacles that restrict the clinical use of benzodiazepines (BDZ). In order to explore the mechanism of these two adverse reactions, changes of neuropeptide Y (NPY) and its receptors in the hippocampus of rat models, in relation to flurazepam (FZP, a member of BDZ) tolerance and dependence, were investigated. METHODS The mRNA of preproNPY and its receptors (Y1, Y2, and Y5) in the hippocampus were determined by competitive RT-PCR, and the distribution of NPY in the hippocampus was examined by immunohistochemistry. RESULTS A decrease of preproNPY mRNA in the hippocampus was found in tolerant and dependent rats. The level of preproNPY mRNA in the hippocampus was reversely correlated with the degree of tolerance and dependence, measured by the threshold of pentylenetetrazol-induced seizures. Immunohistochemistry indicated a decrease of NPY-immunoreactive material in neurons of the CA1, CA3, and dentate gyrus regions of both tolerant and dependent rats. The mRNA of NPY receptors Y1 and Y5 decreased in tolerant rats but did not change in dependent rats. The mRNA of NPY receptor Y2 increased in tolerant rats but decreased in dependent rats. CONCLUSION A decrease of NPY in the hippocampus might be involved in anticonvulsant tolerance and dependence following long-term treatment with FZP. Y1, Y2, and Y5 mRNA were also altered in FZP tolerance and dependence.
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Affiliation(s)
- Li-Ping Zhang
- Department of Pediatrics, Peking University First Hospital, Beijing 100034, China
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28
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Woldbye DPD, Nanobashvili A, Sørensen AT, Husum H, Bolwig TG, Sørensen G, Ernfors P, Kokaia M. Differential suppression of seizures via Y2 and Y5 neuropeptide Y receptors. Neurobiol Dis 2005; 20:760-72. [PMID: 15979311 DOI: 10.1016/j.nbd.2005.05.010] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2004] [Revised: 04/14/2005] [Accepted: 05/12/2005] [Indexed: 10/25/2022] Open
Abstract
Neuropeptide Y (NPY) prominently inhibits epileptic seizures in different animal models. The NPY receptors mediating this effect remain controversial partially due to lack of highly selective agonists and antagonists. To circumvent this problem, we used various NPY receptor knockout mice with the same genetic background and explored anti-epileptic action of NPY in vitro and in vivo. In Y2 (Y2-/-) and Y5 (Y5-/-) receptor knockouts, NPY partially inhibited 0 Mg2+-induced epileptiform activity in hippocampal slices. In contrast, in double knockouts (Y2Y5-/-), NPY had no effect, suggesting that in the hippocampus in vitro both receptors mediate anti-epileptiform action of NPY in an additive manner. Systemic kainate induced more severe seizures in Y5-/- and Y2Y5-/-, but not in Y2-/- mice, as compared to wild-type mice. Moreover, kainate seizures were aggravated by administration of the Y5 antagonist L-152,804 in wild-type mice. In Y5-/- mice, hippocampal kindling progressed faster, and afterdischarge durations were longer in amygdala, but not in hippocampus, as compared to wild-type controls. Taken together, these data suggest that, in mice, both Y2 and Y5 receptors regulate hippocampal seizures in vitro, while activation of Y5 receptors in extra-hippocampal regions reduces generalized seizures in vivo.
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Affiliation(s)
- David P D Woldbye
- Section of Restorative Neurology, Wallenberg Neuroscience Center, BMC A-11, Lund University Hospital, S-221 84 Lund, Sweden
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29
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Vezzani A, Sperk G. Overexpression of NPY and Y2 receptors in epileptic brain tissue: an endogenous neuroprotective mechanism in temporal lobe epilepsy? Neuropeptides 2004; 38:245-52. [PMID: 15337376 DOI: 10.1016/j.npep.2004.05.004] [Citation(s) in RCA: 133] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/07/2004] [Accepted: 05/15/2004] [Indexed: 11/23/2022]
Abstract
Recurrent epileptic seizures in the rat enhance the expression of neuropeptide Y (NPY) and its mRNA in various brain areas including the hippocampus, cerebral cortex and the amygdala. In the hippocampus, the most prominent expression of NPY is observed in mossy fibers and in GABAergic interneurons. At the same time, expression of Y2 receptors is also increased whereas Y1 receptors are reduced. Similar changes in Y1 and Y2 receptors were observed in the hippocampus of patients with temporal lobe epilepsy (TLE). In contrast to the rat, NPY expression is not enhanced in mossy fibers in TLE. In the same tissue, surviving NPY interneurons show marked axonal sprouting into areas innervated by mossy fibers (dentate hilus, stratum lucidum, inner molecular layer of the dentate gyrus). Stimulation of presynaptic Y2 receptors inhibits glutamate release, and exert an anticonvulsant action in experimental models. Y1 receptors mediate a weak excitatory component of NPY action. These findings suggest that changes in the NPY system induced by seizures represent an endogenous adaptive mechanism aimed at counteracting hyperexcitability underlying epileptic activity. This concept is strongly supported by evidence that genetically modified rats overexpressing the NPY gene are less susceptible to seizures while deletion of NPY or Y2 receptor genes results in increased susceptibility to seizures.
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Affiliation(s)
- Annamaria Vezzani
- Department of Neuroscience, Laboratory of Experimental Neurology, Mario Negri Institute for Pharmacology Research, Via Eritrea 62, 20157 Milan, Italy.
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30
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Abstract
The endogenous NPY system in the brain is centrally involved in seizure regulation. The present paper reviews the evidence that exogenously applied NPY receptor ligands can inhibit epileptic seizures in various rodent in vitro and in vivo models. Agonists at Y2 and/or Y5 receptors and antagonists at Y1 receptors appear to inhibit seizures, depending on the seizure model studied. Although progress has been made, further studies are needed using transgenic animals as well as novel selective agonists and antagonists to firmly identify the NPY receptors mediating antiepileptic effects. This may lead to the development of future antiepileptic drug treatments targeting the NPY system.
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Affiliation(s)
- D P D Woldbye
- Laboratory of Neuropsychiatry, Rigshospitalet University Hospital and Department of Pharmacology, University of Copenhagen, 9 Blegdamsvej, DK-2100 Copenhagen, Denmark.
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31
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Baraban SC. Neuropeptide Y and epilepsy: recent progress, prospects and controversies. Neuropeptides 2004; 38:261-5. [PMID: 15337378 DOI: 10.1016/j.npep.2004.04.006] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/25/2004] [Accepted: 04/24/2004] [Indexed: 10/26/2022]
Abstract
Neuropeptide Y (NPY), a 36 amino-acid member of the pancreatic polypeptide family, has received considerable attention in recent years as an endogenous modulator of epileptic activity. Prominently expressed in brain regions involved in seizure generation and propagation, NPY can exert powerful effects on synaptic transmission. Here, we discuss the anti-epileptic actions of NPY and receptor subtypes responsible.
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Affiliation(s)
- S C Baraban
- Epilepsy Research Laboratory, Department of Neurological Surgery, University of California, 513 Parnassus Avenue, San Francisco, CA 94143, USA.
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Baraban SC, Tallent MK. Interneuron Diversity series: Interneuronal neuropeptides--endogenous regulators of neuronal excitability. Trends Neurosci 2004; 27:135-42. [PMID: 15036878 DOI: 10.1016/j.tins.2004.01.008] [Citation(s) in RCA: 143] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Interneurons are often classified according to neuropeptide content. However, it is becoming increasingly clear that neuropeptides are more than convenient neurochemical markers and can act as important modulators of neuronal activity. Recent advances in understanding neuropeptide release and physiological actions suggest that the interneuronal system of neuropeptides is crucial for maintaining appropriate brain function under normal and pathophysiological conditions. In particular, interneuronal neuropeptides appear to play roles in cognition and as endogenous anti-epileptic agents. This article describes current understanding of the conditions under which neuropeptides are released from interneurons, their specific effects on neuronal excitability and synaptic transmission, and the consequences of their loss of function.
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Affiliation(s)
- Scott C Baraban
- Department of Neurological Surgery and PIBS Graduate Program in Neuroscience, University of California, San Francisco, CA 94143-0520, USA
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Vezzani A. Neuropeptide Y and Y1 Receptors in Kindling Epileptogenesis. Epilepsy Curr 2004; 4:100-2. [PMID: 16059463 PMCID: PMC1176335 DOI: 10.1111/j.1535-7597.2004.43006.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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Malva JO, Silva AP, Cunha RA. Presynaptic modulation controlling neuronal excitability and epileptogenesis: role of kainate, adenosine and neuropeptide Y receptors. Neurochem Res 2003; 28:1501-15. [PMID: 14570395 DOI: 10.1023/a:1025618324593] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Based on the idea that seizures may arise from an overshoot of excitation over inhibition, all substances that may decrease glutamatergic function while having no effect or even increasing GABAergic neurotransmission are likely to be effective anticonvulsants. We now review the possible role of three such neuromodulators, kainate, adenosine, and neuropeptide Y receptors in controlling hyperexcitability and epileptogenesis. Particular emphasis is given on the robust neuromodulatory role of these three groups of receptors on the release of glutamate in the hippocampus, a main focus of epilepsy. Moreover, we also give special attention to the mechanisms of receptor activation and coupled signaling events that can be explored as attractive targets for the treatment of epilepsy and excitotoxicity. The present paper is a tribute to Arsélio Pato de Carvalho who has been the main driving force for the development of Neuroscience in Portugal, notably with a particular emphasis on the presynaptic mechanisms of modulation of neurotransmitter release.
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Affiliation(s)
- João O Malva
- Center for Neuroscience of Coimbra, Institute of Biochemistry, Faculty of Medicine, University of Coimbra, 3004-504 Coimbra, Portugal.
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Benmaamar R, Pham-Lê BT, Marescaux C, Pedrazzini T, Depaulis A. Induced down-regulation of neuropeptide Y-Y1 receptors delays initiation of kindling. Eur J Neurosci 2003; 18:768-74. [PMID: 12925003 DOI: 10.1046/j.1460-9568.2003.02810.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Neuropeptide Y appears to modulate epileptic seizures differentially according to the receptor subtypes involved. In the hippocampus, neuropeptide Y expression and release are enhanced in different models of epileptogenesis. On the contrary, the expression of Y1 receptors is decreased and it has been shown that activation of these receptors has pro-convulsant effects. The aim of our study was to investigate the role of Y1 receptors during hippocampal kindling epileptogenesis using (i) knock-out mice lacking Y1 receptors and (ii) intrahippocampal infusion of Y1 antisense oligodeoxynucleotide in rats. Y1 knock-out mice showed similar susceptibility to seizure induction and presented no difference in kindling development as compared with their control littermates. Conversely, local hippocampal down-regulation of Y1 receptors during the first week of hippocampal kindling, induced by a local infusion of a Y1 antisense oligodeoxynucleotide, significantly increased seizure threshold intensity and decreased afterdischarge duration. A reverse effect was observed during the week following the infusion period, which was confirmed by a significant decrease in the number of hippocampal stimulations necessary to evoke generalized seizures. At the end of this second week, an up-regulation of Y1 receptors was observed in kindled rats infused with the antisense as compared with the mismatch-treated controls. Our results in the rat suggest that the down-regulation of Y1 receptors in the hippocampus participates in the control of the initiation of epileptogenesis. The lack of an effect of the deficiency of Y1 receptors in the control of kindling development in Y1 knock-out mice could be due to compensatory mechanisms.
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Affiliation(s)
- Ramla Benmaamar
- Laboratoire de Neuropharmacologie et Neurobiologie des Epilepsies, 11 Rue Humann, 67085 Strasbourg, France.
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Rodi D, Mazzuferi M, Bregola G, Dumont Y, Fournier A, Quirion R, Simonato M. Changes in NPY-mediated modulation of hippocampal [3H]D-aspartate outflow in the kindling model of epilepsy. Synapse 2003; 49:116-24. [PMID: 12740867 DOI: 10.1002/syn.10216] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The anticonvulsant effect of NPY may depend on Y(2) and/or Y(5) receptor-mediated inhibition of glutamate release in critical areas, such as the hippocampus. However, Y(2) and Y(5) receptor levels have been reported to increase and decrease, respectively, in the epileptic hippocampus, implicating that the profile of NPY effects may change accordingly. The aim of this study was to evaluate the differential effects of NPY on glutamate release in the normal and in the epileptic hippocampus. Thus, we pharmacologically characterized the effects of NPY on the release of [(3)H]D-aspartate, a valid marker of endogenous glutamate, from synaptosomes prepared from the whole hippocampus and from the three hippocampal subregions (dentate gyrus and CA1 and CA3 subfields) of control and kindled rats, killed 1 week after the last stimulus-evoked seizure. In the whole hippocampus, NPY does not significantly affect stimulus-evoked [(3)H]D-aspartate overflow. In synaptosomes prepared from control rats, NPY significantly inhibited 15 mM K(+)-evoked [(3)H]D-aspartate overflow only in the CA1 subfield (approx. -30%). Both Y(2) and Y(5) receptor antagonists (respectively, 1 microM BIIE0246 and 1 microM CGP71683A) prevented this effect, suggesting the involvement of both receptor types. In contrast, in synaptosomes prepared from kindled rats NPY significantly inhibited 15 mM K(+)-evoked [(3)H]D-aspartate overflow in the CA1 subfield and in the dentate gyrus (approx. -30%). Only the Y(2) (not the Y(5)) antagonist prevented these effects. These data indicate a critical role for the Y(2) receptor in the inhibitory control of glutamate release in the kindled hippocampus and, thus, suggest that the anticonvulsant effect of NPY in the epileptic brain is most likely Y(2), but not Y(5), receptor-mediated.
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Affiliation(s)
- Donata Rodi
- Department of Clinical and Experimental Medicine (Section of Pharmacology), University of Ferrara, 44100 Ferrara, Italy
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Fetissov SO, Jacoby AS, Brumovsky PR, Shine J, Iismaa TP, Hökfelt T. Altered hippocampal expression of neuropeptides in seizure-prone GALR1 knockout mice. Epilepsia 2003; 44:1022-33. [PMID: 12887433 DOI: 10.1046/j.1528-1157.2003.51402.x] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
PURPOSE Mice carrying a deletion of the GALR1 galanin receptor have recently showed spontaneous seizure phenotype with 25% penetrance. To better understand the role of neuropeptides, which are known to undergo complex plasticity changes with development of epileptic seizures, we characterized their expression in the hippocampal formation in GALR1- knockout (-KO) mice with or without seizures and in wild-type (WT) mice. METHODS Immunohistochemistry and in situ hybridization were used to study expression of galanin, neuropeptide Y (NPY), substance P, enkephalin, dynorphin, and cholecystokinin (CCK). RESULTS In GALR1-KO mice that had been displaying seizures, a strong upregulation of galanin immunoreactivity (ir) and messenger RNA (mRNA) was found in the polymorph layer of the dentate gyrus; galanin-ir also appeared in a dense fiber network in the supragranular layer. A strong upregulation of enkephalin was found in the granule cells/mossy fibers, whereas dynorphin mRNA levels were modestly decreased. NPY was strongly expressed in the granule cells/mossy fibers, and an increase of NPY mRNA levels in the polymorph cells was paralleled by an increase of NPY-ir in the molecular layer. An upregulation of substance P-ir was confined to the fibers in the granule and molecular layers, whereas substance P mRNA was increased in the cells of the polymorph layer. Both CCK-ir and mRNA were strongly downregulated in the granule cell/mossy fiber system, but CCK-ir appeared increased in the supragranular and molecular layers. No changes in neuropeptide-ir were found in GALR1-KO mice not displaying seizures. CONCLUSIONS Complex changes in neuropeptide expression in some principal hippocampal neurons and interneurons appear as a characteristic feature of the spontaneous-seizure phenotype in GALR1-KO mice. However, to what extent causal relations exist between this "epilepsia peptidergic profile" and development of seizures requires further clarification.
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38
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Paredes MF, Greenwood J, Baraban SC. Neuropeptide Y modulates a G protein-coupled inwardly rectifying potassium current in the mouse hippocampus. Neurosci Lett 2003; 340:9-12. [PMID: 12648746 DOI: 10.1016/s0304-3940(03)00036-3] [Citation(s) in RCA: 37] [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
Neuropeptide Y (NPY) is an abundant brain peptide with endogenous antiepileptic activity. Here we examined the role played by Y1 receptors (Y1R) in the mouse hippocampus. Using whole-cell patch-clamp recordings, we show that hilar neurons in acute mouse hippocampal slices exhibit a G-protein coupled inwardly rectifying potassium (GIRK) current that is significantly enhanced during exogenous NPY application. NPY-mediated enhancement of GIRK current was observed on 47% of putative interneurons and was mimicked by application of Y1R specific agonist (Leu(31)Pro(34) NPY). Immunostaining revealed the presence of Y1R on cell somas of hilar NPY-containing interneurons. Thus, our results suggest that Y1R on hilar interneurons may act as a peptide autoreceptor.
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Affiliation(s)
- Mercedes F Paredes
- Department of Neurological Surgery,University of California, San Francisco, 513 Parnassus Avenue, San Francisco, CA 94143, USA
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39
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Abstract
It is a central tenet of the epilepsy field that seizures result from the imbalance of excitation over inhibition (1). The bulk of excitation is mediated by the neurotransmitter glutamate, whereas inhibition results mainly from the actions of gamma-aminobutyric acid (GABA). In the neocortex and hippocampus, the intrinsic sources of GABA are the interneurons, which lately have come under intense scrutiny. It has become clear that a large number of distinct types of interneurons can be differentiated in part by the array of neuropeptides they coexpress (cf. (2)). Evidence is emerging that the neuropeptide complement of interneurons plays important roles in the way that interneurons regulate excitability. Here we discuss what is known about the relation of one well-characterized neuropeptide, neuropeptide Y (NPY), and epilepsy in experimental animals and humans, and suggest possible roles for the receptors as targets for the control of excessive excitation in epilepsy.
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Affiliation(s)
- William F. Colmers
- Department of Pharmacology, University of Alberta, Edmonton, Alberta, Canada
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40
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Abstract
It is a central tenet of the epilepsy field that seizures result from the imbalance of excitation over inhibition ( 1 ). The bulk of excitation is mediated by the neurotransmitter glutamate, whereas inhibition results mainly from the actions of γ-aminobutyric acid (GABA). In the neocortex and hippocampus, the intrinsic sources of GABA are the interneurons, which lately have come under intense scrutiny. It has become clear that a large number of distinct types of interneurons can be differentiated in part by the array of neuropeptides they coexpress (cf. 2). Evidence is emerging that the neuropeptide complement of interneurons plays important roles in the way that interneurons regulate excitability. Here we discuss what is known about the relation of one well-characterized neuropeptide, neuropeptide Y (NPY), and epilepsy in experimental animals and humans, and suggest possible roles for the receptors as targets for the control of excessive excitation in epilepsy.
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Affiliation(s)
- William F. Colmers
- />Department of Pharmacology, University of Alberta, Edmonton, Alberta, Canada
| | - Bouchaïb El Bahh
- />Department of Pharmacology, University of Alberta, Edmonton, Alberta, Canada
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41
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Scharfman HE, Sollas AL, Smith KL, Jackson MB, Goodman JH. Structural and functional asymmetry in the normal and epileptic rat dentate gyrus. J Comp Neurol 2002; 454:424-39. [PMID: 12455007 PMCID: PMC2519114 DOI: 10.1002/cne.10449] [Citation(s) in RCA: 114] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The rat dentate gyrus is usually described as relatively homogeneous. Here, we present anatomic and physiological data which demonstrate that there are striking differences between the supra- and infrapyramidal blades after status epilepticus and recurrent seizures. These differences appear to be an accentuation of a subtle asymmetry present in normal rats. In both pilocarpine and kainic acid models, there was greater mossy fiber sprouting in the infrapyramidal blade. This occurred primarily in the middle third of the hippocampus. Asymmetric sprouting was evident both with Timm stain as well as antisera to brain-derived neurotrophic factor (BDNF) or neuropeptide Y (NPY). In addition, surviving NPY-immunoreactive hilar neurons were distributed preferentially in the suprapyramidal region of the hilus. Extracellular recordings from infrapyramidal sites in hippocampal slices of pilocarpine-treated rats showed larger population spikes and weaker paired-pulse inhibition in response to perforant path stimulation relative to suprapyramidal recordings. A single stimulus could evoke burst discharges in infrapyramidal granule cells but not suprapyramidal blade neurons. BDNF exposure led to spontaneous epileptiform discharges that were larger in amplitude and longer lasting in the infrapyramidal blade. Stimulation of the infrapyramidal molecular layer evoked larger responses in area CA3 than suprapyramidal stimulation. In slices from the temporal pole, in which anatomic evidence of asymmetry waned, there was little evidence of physiological asymmetry either. Of interest, some normal rats also showed signs of greater evoked responses in the infrapyramidal blade, and this could be detected with both microelectrode recording and optical imaging techniques. Although there were no signs of hyperexcitability in normal rats, the data suggest that there is some asymmetry in the normal dentate gyrus and this asymmetry is enhanced by seizures. Taken together, the results suggest that supra- and infrapyramidal blades of the dentate gyrus could have different circuit functions and that the infrapyramidal blade may play a greater role in activating the hippocampus.
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Affiliation(s)
- Helen E Scharfman
- Center for Neural Recovery and Rehabilitation Research, Helen Hayes Hospital, West Haverstraw, New York 10993-1195, USA.
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42
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Silva AP, Cavadas C, Grouzmann E. Neuropeptide Y and its receptors as potential therapeutic drug targets. Clin Chim Acta 2002; 326:3-25. [PMID: 12417094 DOI: 10.1016/s0009-8981(02)00301-7] [Citation(s) in RCA: 113] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Neuropeptide Y (NPY) is a 36-amino-acid peptide that exhibits a large number of physiological activities in the central and peripheral nervous systems. NPY mediates its effects through the activation of six G-protein-coupled receptor subtypes named Y(1), Y(2), Y(3), Y(4), Y(5), and y(6). Evidence suggests that NPY is involved in the pathophysiology of several disorders, such as the control of food intake, metabolic disorders, anxiety, seizures, memory, circadian rhythm, drug addiction, pain, cardiovascular diseases, rhinitis, and endothelial cell dysfunctions. The synthesis of agonists and antagonists for these receptors could be useful to treat several of these diseases.
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Affiliation(s)
- Antonio P Silva
- Division of Hypertension and Vascular Medicine, Centre Hospitalier Universitaire Vaudois, Av. Pierre Decker, 1011 Lausanne, Switzerland
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43
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Mazarati A, Wasterlain CG. Anticonvulsant effects of four neuropeptides in the rat hippocampus during self-sustaining status epilepticus. Neurosci Lett 2002; 331:123-7. [PMID: 12361856 DOI: 10.1016/s0304-3940(02)00847-9] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
We compared the anticonvulsant actions of dynorphin A (1-13), galanin, neuropeptide Y and somatostatin in a model of self-sustaining status epilepticus (SSSE). SSSE was induced in adult Wistar rats by 30 min intermittent perforant path stimulation. Peptides or saline were injected into the hilus of the dentate gyrus 10 min after the end of perforant path stimulation. EEG was analyzed using Harmonie software (Stellate systems). While all neuropeptides showed significant seizure protecting effects, their anticonvulsant profiles followed different patterns: somatostatin and NPY induced strong, but transient suppression of spikes and seizures, while seizure suppression by dynorphin and galanin was more profound and irreversible.
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Affiliation(s)
- Andrey Mazarati
- Department of Neurology and Brain Research Institute, University of California, Los Angeles, USA.
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Husum H, Gruber SHM, Bolwig TG, Mathé AA. Extracellular levels of NPY in the dorsal hippocampus of freely moving rats are markedly elevated following a single electroconvulsive stimulation, irrespective of anticonvulsive Y1 receptor blockade. Neuropeptides 2002; 36:363-9. [PMID: 12450742 DOI: 10.1016/s0143-4179(02)00086-0] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Neuropeptide Y (NPY) has been proposed to play a role in the pathophysiology of depression and also to act as an endogenous anticonvulsant. Repeated administration of electroconvulsive stimulations (ECS) has been shown to induce a long-term increase in hippocampal NPY neurotransmission, while the effects of single ECS are largely unexplored. In this study, we assessed extracellular levels of NPY in the dorsal hippocampus of freely moving rats following a single ECS. We also studied the effect of locally administered BIBP3226, a selective NPY Y1 receptor antagonist with reported anticonvulsant properties, on the duration of the ECS-induced seizure and NPY release in freely moving animals. Our data demonstrate that a single ECS increases extracellular NPY-like immunoreactivity (LI) levels in the dorsal hippocampus, reaching statistical significance 2h following the treatment. KCl transiently and calcium-dependently increased extracellular levels of NPY, suggesting that the measured NPY-LI is derived from functional neurons. Local BIBP3226 perfusion essentially abolished the ECS-induced seizure but had no effect on the basal NPY-LI outflow or on the ECS-induced rise in extracellular NPY levels. Our data are in line with the hypothesis that one mechanism of action of ECS is to release NPY in the hippocampus and suggest that the increase is in itself not associated with anticonvulsant activity but may represent other properties of NPY.
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Affiliation(s)
- Henriette Husum
- Institution of Clinical Neuroscience, Karolinska Institutet, SE-17177, Stockholm, Sweden.
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45
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Poulsen FR, Jahnsen H, Blaabjerg M, Zimmer J. Pilocarpine-induced seizure-like activity with increased BNDF and neuropeptide Y expression in organotypic hippocampal slice cultures. Brain Res 2002; 950:103-18. [PMID: 12231234 DOI: 10.1016/s0006-8993(02)03009-3] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Organotypic hippocampal slice cultures were treated with the muscarinic agonist pilocarpine to study induced seizure-like activity and changes in neurotrophin and neuropeptide expression. For establishment of a seizure-inducing protocol, 2-week-old cultures derived from 6-8-day-old rats were exposed to 0.1 mM to 5 mM of pilocarpine for 4 h to 7 days. Other cultures were treated with pilocarpine for 7 days and left for 7-14 days in normal medium. Age-matched, non-treated cultures served as controls. Intracellular recordings from CA1 pyramidal cells revealed increased spontaneous activity in 31 of 35 cultures superfused with 0.1 or 5 mM pilocarpine. Epileptiform discharges were recorded in 17 of the 31 cultures, and 19 displayed frequencies specifically in the 6-12-Hz (Theta rhythm) range when superfused with pilocarpine. The pilocarpine effect was blocked by simultaneous superfusion with the muscarinic receptor antagonist atropine (100 microM). Regardless of dose and exposure time, the pilocarpine treatment induced very limited neuronal cell death, recorded as cellular propidium iodide uptake. Cultures exposed to 5 mM pilocarpine for up to 7 days displayed increased BDNF expression when analyzed by Western blot and ELISA. This BDNF increase correlated with increased neuropeptide Y immunoreactivity, known to accompany seizure activity. Addition of BDNF (200 ng/ml) to otherwise untreated cultures also upregulated NPY expression. The pilocarpine-induced seizure-like activity in hippocampal slice cultures, with concomitant increase in BDNF and NPY expression, is compared with in vivo observations and discussed in terms of the potential use of the easily accessible slice cultures in experimental seizure research.
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Affiliation(s)
- Frantz Rom Poulsen
- Department of Anatomy and Neurobiology, University of Southern Denmark-Odense, Winsloewparken 21, DK-5000 C, Odense, Denmark.
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46
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Abstract
PURPOSE Recent evidence suggests an antiepileptic role for neuropeptide Y (NPY) in the central nervous system. The precise receptor subtypes mediating the inhibitory actions of NPY in the hippocampal formation, however, remain unclear. In vitro studies suggest a role for Y2 receptors in modulating excitatory hippocampal synaptic transmission and epileptiform discharge. In vivo studies implicate Y5 receptors. Here we used pharmacologic tools and Y5-receptor knockout mice to examine the role of Y5 receptors in mediating the antiexcitatory and antiepileptic actions of NPY in the hippocampal formation. METHODS Hippocampal slices were obtained from age-matched wild-type (WT; 129 s3/svimj) and Y5-receptor knockout (Y5R KO) mice generated on the same background strain. Extracellular or whole-cell voltage-clamp recordings were obtained in area CA3 pyramidale. Evoked population spikes or excitatory postsynaptic currents were monitored during bath application of NPY, NPY13-36, or human pancreatic polypeptide (hPP). In some slices, zero-magnesium cerebrospinal fluid (CSF) was used to evoke spontaneous epileptiform discharges. RESULTS NPY and NPY agonists with preference for either Y2 (NPY13-36) or Y5 (hPP) receptor subtypes caused a significant reduction in population spike and excitatory postsynaptic current (EPSC) amplitudes in slices from WT mice. NPY (and NPY agonists) also suppressed zero-magnesium epileptiform burst discharge in slices from WT mice. In contrast, bath application of NPY, NPY13-36, or hPP had no effect in slices from Y5R KO mice. CONCLUSIONS NPY modulates excitatory synaptic transmission and inhibits limbic seizure activity in the mouse hippocampus. The antiepileptic actions of NPY, in the mouse, appear to require activation of hippocampal Y5 receptors.
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Affiliation(s)
- Scott C Baraban
- Department of Neurological Surgery, University of California-San Francisco, 513 Parnassus Avenue, San Francisco, CA 94143, USA.
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47
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Vezzani A, Michalkiewicz M, Michalkiewicz T, Moneta D, Ravizza T, Richichi C, Aliprandi M, Mulé F, Pirona L, Gobbi M, Schwarzer C, Sperk G. Seizure susceptibility and epileptogenesis are decreased in transgenic rats overexpressing neuropeptide Y. Neuroscience 2002; 110:237-43. [PMID: 11958866 DOI: 10.1016/s0306-4522(01)00581-4] [Citation(s) in RCA: 81] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Functional studies in epileptic tissue indicate that neuropeptide Y and some of its peptide analogs potently inhibit seizure activity. We investigated seizure susceptibility in transgenic rats overexpressing the rat neuropeptide Y gene under the control of its natural promoter. Seizures were induced in adult transgenic male rats and their wild-type littermates by i.c.v. injection of 0.3 microg kainic acid or by electrical kindling of the dorsal hippocampus. Transgenic rats showed a significant reduction in the number and duration of electroencephalographic seizures induced by kainate by 30% and 55% respectively (P<0.05 and 0.01). Transgenic rats were also less susceptible to epileptogenesis than wild-type littermates as demonstrated by a 65% increase in the number of electrical stimuli required to induce stage 5 seizures (P<0.01). This phenotype was associated with a strong and specific expression of neuropeptide Y mRNA in area CA1, a brain area involved in the seizure network. We conclude that endogenous neuropeptide Y overexpression in the rat hippocampus is associated with inhibition of seizures and epileptogenesis suggesting that this system may be a valuable target for developing novel antiepileptic treatments.
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Affiliation(s)
- A Vezzani
- Department of Neurosciences, Istituo di Richerche Farmacologie Mario Negri, Milan, Italy.
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Abstract
Neuropeptide Y (NPY), a peptide abundantly expressed in the mammalian nervous system, has been extensively studied using traditional pharmacological and behavioral models. Central administration of NPY or synthetic ligands for its receptors has indicated a role of NPY in anxiety-related behaviors, feeding, regulation of blood pressure, circadian rhythm and other functions. Some limitations inherent in pharmacological approaches, such as lack of selectivity of receptor antagonists, can be elegantly circumvented using genetically modified animals. For NPY, mice lacking NPY, the Y1, the Y2 or the Y5 receptors have been generated. In addition, both mice and rats overexpressing NPY in the central nervous system are available. Here, we review the research carried out so far in the NPY-field using genetically modified animals. Together, these models indicate that stress-related behaviors and regulation of voluntary alcohol intake perhaps are among the most important functions of central NPY, and may provide attractive targets for developing novel therapies in depression, anxiety disorders and alcohol dependence.
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Affiliation(s)
- A Thorsell
- 1Department of Neuropharmacology, The Scripps Research Institute, CVN-15, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA.
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49
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Abstract
Marked expression of neuropeptide Y (NPY) and its Y2 receptors in hippocampal mossy fibers has been reported in animal models of epilepsy. Because NPY can suppress glutamate release by activating presynaptic Y2 receptors, these changes have been proposed as an endogenous protective mechanism. Therefore, we investigated whether similar changes in the NPY system may also take place in human epilepsy. We investigated Y1 and Y2 receptor binding and NPY immunoreactivity in hippocampal specimens that were obtained at surgery from patients with temporal lobe epilepsy and in autopsy controls. Significant increases in Y2 receptor binding (by 43-48%) were observed in the dentate hilus, sectors CA1 to CA3, and subiculum of specimens with, but not in those without, hippocampal sclerosis. On the other hand, Y1 receptor binding was significantly reduced (by 62%) in the dentate molecular layer of sclerotic specimens. In the same patients, the total lengths of NPY immunoreactive (NPY-IR) fibers was markedly increased (by 115-958%) in the dentate molecular layer and hilus, in the stratum lucidum of CA3, and throughout sectors CA1 to CA3 and the subiculum, as compared with autopsies. In nonsclerotic specimens, increases in lengths of NPY-IR fibers were more moderate and statistically not significant. NPY mRNA was increased threefold in hilar interneurons of sclerotic and nonsclerotic specimens. It is suggested that abundant sprouting of NPY fibers, concomitant upregulation of Y2 receptors, and downregulation of Y1 receptors in the hippocampus of patients with Ammon's horn sclerosis may be endogenous anticonvulsant mechanisms.
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50
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Reibel S, Nadi S, Benmaamar R, Larmet Y, Carnahan J, Marescaux C, Depaulis A. Neuropeptide Y and epilepsy: varying effects according to seizure type and receptor activation. Peptides 2001; 22:529-39. [PMID: 11287111 DOI: 10.1016/s0196-9781(01)00347-3] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
In vitro and in vivo experiments suggest antiepileptic properties for NPY. In this study, the pharmacology of these effects was examined and compared in different rat models of seizures. Agonists for Y(1), Y(2) and Y(5) receptors reduced seizure-like activity in hippocampal cultures. Intracerebral injection of NPY or Y(5) agonists reduced the expression of focal seizures produced by a single electrical stimulation of the hippocampus. Conversely, NPY agonists increased the duration of generalized convulsive seizures induced by pentylenetetrazol. These results suggest that NPY reduces seizures of hippocampal origin through activation of Y(5) receptors. They also point to probable modulatory effects of NPY in brain structures other than the hippocampus, involved in initiation, propagation or control of seizures.
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Affiliation(s)
- S Reibel
- INSERM U398, Faculté de Médecine, 11 rue Humann, 67085, Strasbourg cedex, France.
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