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Progress report on new antiepileptic drugs: A summary of the Tenth Eilat Conference (EILAT X). Epilepsy Res 2010; 92:89-124. [DOI: 10.1016/j.eplepsyres.2010.09.001] [Citation(s) in RCA: 125] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2010] [Revised: 08/25/2010] [Accepted: 09/12/2010] [Indexed: 01/09/2023]
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52
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Christiansen SH, Woldbye DPD. Regulation of the galanin system by repeated electroconvulsive seizures in mice. J Neurosci Res 2010; 88:3635-43. [PMID: 20936701 DOI: 10.1002/jnr.22517] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2010] [Revised: 07/30/2010] [Accepted: 08/26/2010] [Indexed: 11/07/2022]
Abstract
Even though induction of seizures by electroconvulsive stimulation (ECS) is a treatment widely used for major depression in humans, the working mechanism of ECS remains uncertain. The antiepileptic effect of ECS has been suggested to be involved in mediating the therapeutic effect of ECS. The neuropeptide galanin exerts antiepileptic and antidepressant-like effects and has also been implicated in the pathophysiology of depression. To explore a potential role of galanin in working mechanisms of ECS, the present study examined effects of repeated ECS on the galanin system using QRT-PCR, in situ hybridization, and [(125) I]galanin receptor binding. ECS was administered to adult mice daily for 14 days, and this paradigm was confirmed to exert antidepressant-like effect in the tail suspension test. Prominent increases in galanin gene expression were found in several brain regions involved in regulation of epileptic activity and depression, including the piriform cortex, hippocampal dentate gyrus, and amygdala. Likewise, GalR2 gene expression was up-regulated in both the central and the medial amygdala, whereas GalR1 gene expression showed a modest down-regulation in the medial amygdala. [(125) I]galanin receptor binding in the piriform cortex, hippocampus, and amygdala was found to be significantly down-regulated. These data show that the galanin system is regulated by repeated ECS in a number of brain regions implicated in seizure regulation and depression. These changes may play a role in the therapeutic effect of ECS.
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Affiliation(s)
- S H Christiansen
- Laboratory of Neuropsychiatry, Psychiatric Centre Copenhagen, and Department of Neuroscience and Pharmacology, University of Copenhagen, Copenhagen, Denmark
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53
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GalR2-positive allosteric modulator exhibits anticonvulsant effects in animal models. Proc Natl Acad Sci U S A 2010; 107:15229-34. [PMID: 20660766 DOI: 10.1073/pnas.1008986107] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Galanin receptors type 1 (GalR1) and/or type 2 (GalR2) represent unique pharmacological targets for treatment of seizures and epilepsy. Previous studies have shown that the endogenous peptide ligand galanin exerts powerful anticonvulsant effect through activation of these two G protein-coupled receptors, which are highly expressed in the temporal lobe of rodent brain. Here we report the characterization of a putative GalR2-positive allosteric modulator CYM2503. CYM2503 potentiated the galanin-stimulated IP1 accumulation in HEK293 cells stably expressing GalR2 receptor, whereas it exhibited no detectable affinity for the (125)I galanin-binding site of GalR2 receptor, an effect consistent with that of a positive allosteric modulator. In the rat Li-pilocarpine status epilepticus model, CYM2503, injected intraperitoneally, increased the latency to first electrographic seizure and the latency to first stage 3 behavioral seizure, decreased the latency to the establishment of status epilepticus, and dramatically decreased the mortality. In a Li-pilocarpine seizure model in mice, CYM2503 increased the latency to first electrographic seizure and decreased the total time in seizure. CYM2503 also attenuated electroshock-induced seizures in mice. Thus, CYM2503 provides a starting point for the development of anticonvulsant therapy using the galanin R2 receptor as target.
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Sankar R, Auvin S, Kwon YS, Pineda E, Shin D, Mazarati A. Evaluation of development-specific targets for antiepileptogenic therapy using rapid kindling. Epilepsia 2010; 51 Suppl 3:39-42. [PMID: 20618398 PMCID: PMC2912152 DOI: 10.1111/j.1528-1167.2010.02607.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We used the method of rapid hippocampal kindling to assess the potential antiepileptogenic efficacy of a number of anticonvulsant medications. This method afforded a higher throughput than methods based on traditional kindling or post-status epilepticus models of epileptogenesis. This "compressed epileptogenesis" model also permitted the study of age-dependent pharmacologic targets, and distinguished among antiepileptic drugs (AEDs) on the basis of their age-specific antiepileptogenic efficacy. We found retigabine to be the most effective anticonvulsant therapy during early development. Topiramate seemed most effective further along development, whereas some drugs did not demonstrate an age-specific effect. The method also reproduced some of the paradoxical pharmacologic findings previously shown with lamotrigine. Although the utility of this model for screening the antiepileptogenic therapies requires further validation, it introduces the ability to undertake development-specific testing and a more rapid throughput than conventional methods.
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Affiliation(s)
- Raman Sankar
- Department of Pediatrics, David Geffen School of Medicine at UCLA, Los Angeles, California, USA.
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55
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Zhang L, Robertson CR, Green BR, Pruess TH, White HS, Bulaj G. Structural requirements for a lipoamino acid in modulating the anticonvulsant activities of systemically active galanin analogues. J Med Chem 2010; 52:1310-6. [PMID: 19199479 DOI: 10.1021/jm801397w] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Introduction of lipoamino acid (LAA), Lys-palmitoyl, and cationization into a series of galanin analogues yielded systemically active anticonvulsant compounds. To study the relationship between the LAA structure and anticonvulsant activity, orthogonally protected LAAs were synthesized in which the Lys side chain was coupled to fatty acids varying in length from C(8) to C(18) or was coupled to a monodispersed polyethylene glycol, PEG(4). Galanin receptor affinity, serum stability, lipophilicity (log D), and activity in the 6 Hz mouse model of epilepsy of each of the newly synthesized analogues were determined following systemic administration. The presence of various LAAs or Lys(MPEG(4)) did not affect the receptor binding properties of the modified peptides, but their anticonvulsant activities varied substantially and were generally correlated with their lipophilicity. Our results suggest that varying the length or polarity of the LAA residue adjacent to positively charged amino acid residues may effectively modulate the antiepileptic activity of the galanin analogues.
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Affiliation(s)
- Liuyin Zhang
- Department of Medicinal Chemistry, College of Pharmacy, University of Utah, Salt Lake City, Utah, 84108, USA
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56
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Emerging roles for G protein-gated inwardly rectifying potassium (GIRK) channels in health and disease. Nat Rev Neurosci 2010; 11:301-15. [PMID: 20389305 DOI: 10.1038/nrn2834] [Citation(s) in RCA: 454] [Impact Index Per Article: 32.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
G protein-gated inwardly rectifying potassium (GIRK) channels hyperpolarize neurons in response to activation of many different G protein-coupled receptors and thus control the excitability of neurons through GIRK-mediated self-inhibition, slow synaptic potentials and volume transmission. GIRK channel function and trafficking are highly dependent on the channel subunit composition. Pharmacological investigations of GIRK channels and studies in animal models suggest that GIRK activity has an important role in physiological responses, including pain perception and memory modulation. Moreover, abnormal GIRK function has been implicated in altering neuronal excitability and cell death, which may be important in the pathophysiology of diseases such as epilepsy, Down's syndrome, Parkinson's disease and drug addiction. GIRK channels may therefore prove to be a valuable new therapeutic target.
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57
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Robertson CR, Scholl EA, Pruess TH, Green BR, White HS, Bulaj G. Engineering galanin analogues that discriminate between GalR1 and GalR2 receptor subtypes and exhibit anticonvulsant activity following systemic delivery. J Med Chem 2010; 53:1871-5. [PMID: 20121116 DOI: 10.1021/jm9018349] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Galanin modulates seizures in the brain through two galanin receptor subtypes, GalR1 and GalR2. To generate systemically active galanin receptor ligands that discriminate between GalR1 and GalR2, the GalR1-preferring analogue Gal-B2 (or NAX 5055) was rationally redesigned to yield GalR2-preferring analogues. Systematic truncations of the N-terminal backbone led to [N-Me,des-Sar]Gal-B2, containing N-methyltryptophan. This analogue exhibited 18-fold preference in binding toward GalR2, maintained agonist activity, and exhibited potent anticonvulsant activity in mice following intraperitoneal administration.
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Affiliation(s)
- Charles R Robertson
- Department of Medicinal Chemistry, College of Pharmacy, University of Utah, 421 WakaraWay, Salt Lake City, Utah 84108, USA
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58
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Abstract
In the last fifteen years, new antiepileptic medications have been offered for the treatment of patients with epilepsy. Nevertheless, despite optimal medical treatment, up to 30% of patients still experience recurrent seizures and the challenge for new, more efficacious and better-tolerated drugs continues. New antiepileptic drugs include the evolution of pre-existing drugs and new compounds identified through the investigation of additional molecular targets, such as SV2A synaptic vesicle protein, voltage-gated potassium channels, ionotropic and metabotropic glutamate receptors, and gap junctions. This paper reviews the available information on various classes of molecules that are in the pipeline as well as on the innovative approaches to the treatment of epilepsy.
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Affiliation(s)
- Pasquale Striano
- Muscular & Neurodegenerative Diseases Unit, Institute G. Gaslini, Genova, Italy
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59
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Binding of Chimeric Peptides M617 and M871 to Galanin Receptor Type 3 Reveals Characteristics of Galanin Receptor–Ligand Interaction. Int J Pept Res Ther 2010. [DOI: 10.1007/s10989-009-9197-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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60
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Mitsukawa K, Lu X, Bartfai T. Galanin, galanin receptors, and drug targets. EXPERIENTIA SUPPLEMENTUM (2012) 2010; 102:7-23. [PMID: 21299058 DOI: 10.1007/978-3-0346-0228-0_2] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Galanin, a neuropeptide widely expressed in the central and peripheral nervous systems and in the endocrine system, has been shown to regulate numerous physiological and pathological processes through interactions with three G-protein-coupled receptors, GalR1 through GalR3. Over the past decade, some of the receptor subtype-specific effects have been elucidated through pharmacological studies using subtype selective ligands, as well as through molecular approaches involving knockout animals. In this chapter, we summarize the current data which constitute the basis of targeting GalR1, GalR2, and GalR3 for the treatment of various human diseases and pathological conditions, including seizure, Alzheimer's disease, mood disorders, anxiety, alcohol intake in addiction, metabolic diseases, pain and solid tumors.
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Affiliation(s)
- K Mitsukawa
- Molecular and Integrative Neurosciences Department, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
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61
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Counts SE, Perez SE, Ginsberg SD, Mufson EJ. Neuroprotective role for galanin in Alzheimer's disease. EXPERIENTIA SUPPLEMENTUM (2012) 2010; 102:143-62. [PMID: 21299067 DOI: 10.1007/978-3-0346-0228-0_11] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Galanin (GAL) and GAL receptors (GALR) are overexpressed in degenerating brain regions associated with cognitive decline in Alzheimer's disease (AD). The functional consequences of GAL plasticity in AD are unclear. GAL inhibits cholinergic transmission in the hippocampus and impairs spatial memory in rodent models, suggesting that GAL overexpression exacerbates cognitive impairment in AD. By contrast, gene expression profiling of individual cholinergic basal forebrain (CBF) neurons aspirated from AD tissue revealed that GAL hyperinnervation positively regulates mRNAs that promote CBF neuronal function and survival. GAL also exerts neuroprotective effects in rodent models of neurotoxicity. These data support the growing concept that GAL overexpression preserves CBF neuron function, which may in turn delay the onset of symptoms of AD. Further elucidation of GAL activity in selectively vulnerable brain regions will help gauge the therapeutic potential of GALR ligands in the treatment of AD.
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Affiliation(s)
- Scott E Counts
- Department of Neurological Sciences, Rush University Medical Center, 1735 West Harrison Street, Suite 300, Chicago, IL 60612, USA
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62
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Runesson J, Saar I, Lundström L, Järv J, Langel U. A novel GalR2-specific peptide agonist. Neuropeptides 2009; 43:187-92. [PMID: 19467704 DOI: 10.1016/j.npep.2009.04.004] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/18/2008] [Revised: 03/16/2009] [Accepted: 04/17/2009] [Indexed: 01/08/2023]
Abstract
The galanin peptide family and its three receptors have with compelling evidence been implicated in several high-order physiological disorders. The co-localization with other neuromodulators and the distinct up-regulation during and after pathological disturbances has drawn attention to this neuropeptide family. In the current study we present data on receptor binding and functional response for a novel galanin receptor type 2 (GalR2) selective chimeric peptide, M1145 [(RG)(2)-N-galanin(2-13)-VL-(P)(3)-(AL)(2)-A-amide]. The M1145 peptide shows more than 90-fold higher affinity for GalR2 over GalR1 and a 76-fold higher affinity over GalR3. Furthermore, the peptide yields an agonistic effect in vitro, seen as an increase in inositol phosphate (IP) accumulation, both in the absence or the presence of galanin. The peptide design with a N-terminal extension of galanin(2-13), prevails new insights in the assembly of novel subtype specific ligands for the galanin receptor family and opens new possibilities to apply the galanin system as a putative drug target.
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Affiliation(s)
- Johan Runesson
- Department of Neurochemistry, Stockholm University, Svante Arrheniusv. 21A, SE-10691 Stockholm, Sweden.
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63
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White HS, Scholl EA, Klein BD, Flynn SP, Pruess TH, Green BR, Zhang L, Bulaj G. Developing novel antiepileptic drugs: characterization of NAX 5055, a systemically-active galanin analog, in epilepsy models. Neurotherapeutics 2009; 6:372-80. [PMID: 19332332 PMCID: PMC4402707 DOI: 10.1016/j.nurt.2009.01.001] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2008] [Accepted: 01/09/2009] [Indexed: 11/25/2022] Open
Abstract
The endogenous neuropeptide galanin and its associated receptors galanin receptor 1 and galanin receptor 2 are highly localized in brain limbic structures and play an important role in the control of seizures in animal epilepsy models. As such, galanin receptors provide an attractive target for the development of novel anticonvulsant drugs. Our efforts to engineer galanin analogs that can penetrate the blood-brain-barrier and suppress seizures, yielded NAX 5055 (Gal-B2), a systemically-active analog that maintains low nanomolar affinity for galanin receptors and displays a potent anticonvulsant activity. In this report, we show that NAX 5055 is active in three models of epilepsy: 1) the Frings audiogenic seizure-susceptible mouse, 2) the mouse corneal kindling model of partial epilepsy, and 3) the 6 Hz model of pharmacoresistant epilepsy. NAX 5055 was not active in the traditional maximal electroshock and subcutaneous pentylenetetrazol seizure models. Unlike most antiepileptic drugs, NAX 5055 showed high potency in the 6 Hz model of epilepsy across all three different stimulation currents; i.e., 22, 32 and 44 mA, suggesting a potential use in the treatment of pharmacoresistant epilepsy. Furthermore, NAX 5055 was found to be biologically active after intravenous, intraperitoneal, and subcutaneous administration, and efficacy was associated with a linear pharmacokinetic profile. The results of the present investigation suggest that NAX 5055 is a first-in-class neurotherapeutic for the treatment of epilepsy in patients refractory to currently approved antiepileptic drugs.
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Affiliation(s)
- H Steve White
- Department of Pharmacology, College of Pharmacy, University of Utah, Salt Lake City, Utah 84108, USA.
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64
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Brown JS. Effects of bisphenol-A and other endocrine disruptors compared with abnormalities of schizophrenia: an endocrine-disruption theory of schizophrenia. Schizophr Bull 2009; 35:256-78. [PMID: 18245062 PMCID: PMC2643957 DOI: 10.1093/schbul/sbm147] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
In recent years, numerous substances have been identified as so-called "endocrine disruptors" because exposure to them results in disruption of normal endocrine function with possible adverse health outcomes. The pathologic and behavioral abnormalities attributed to exposure to endocrine disruptors like bisphenol-A (BPA) have been studied in animals. Mental conditions ranging from cognitive impairment to autism have been linked to BPA exposure by more than one investigation. Concurrent with these developments in BPA research, schizophrenia research has continued to find evidence of possible endocrine or neuroendocrine involvement in the disease. Sufficient information now exists for a comparison of the neurotoxicological and behavioral pathology associated with exposure to BPA and other endocrine disruptors to the abnormalities observed in schizophrenia. This review summarizes these findings and proposes a theory of endocrine disruption, like that observed from BPA exposure, as a pathway of schizophrenia pathogenesis. The review shows similarities exist between the effects of exposure to BPA and other related chemicals with schizophrenia. These similarities can be observed in 11 broad categories of abnormality: physical development, brain anatomy, cellular anatomy, hormone function, neurotransmitters and receptors, proteins and factors, processes and substances, immunology, sexual development, social behaviors or physiological responses, and other behaviors. Some of these similarities are sexually dimorphic and support theories that sexual dimorphisms may be important to schizophrenia pathogenesis. Research recommendations for further elaboration of the theory are proposed.
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Affiliation(s)
- James S Brown
- Department of Psychiatry, VCU School of Medicine, Richmond, VA, USA.
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Kong S, Lorenzana A, Deng Q, McNeill TH, Schauwecker PE. Variation in Galr1 expression determines susceptibility to exocitotoxin-induced cell death in mice. GENES BRAIN AND BEHAVIOR 2008; 7:587-98. [PMID: 18363852 DOI: 10.1111/j.1601-183x.2008.00395.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Inbred strains of mice differ in their susceptibility to excitotoxin-induced cell death, but the genetic basis of individual variation in differential susceptibility is unknown. Previously, we identified a highly significant quantitative trait locus (QTL) on chromosome 18 that influenced susceptibility to kainic acid-induced cell death (Sicd1). Comparison of susceptibility to seizure-induced cell death between reciprocal congenic lines for Sicd1 and parental background mice indicates that genes influencing this trait were captured in both strains. Two positional gene candidates, Galr1 and Mbp, map to 55 cM, where the Sicd1 QTL had been previously mapped. Thus, this study was undertaken to determine if Galr1 and/or Mbp could be considered as candidate genes. Genomic sequence comparison of these two functional candidate genes from the C57BL/6J (resistant at Sicd1) and the FVB/NJ (susceptible at Sicd1) strains showed no single-nucleotide polymorphisms. However, expression studies confirmed that Galr1 shows significant differential expression in the congenic and parental inbred strains. Galr1 expression was downregulated in the hippocampus of C57BL/6J mice and FVB.B6-Sicd1 congenic mice when compared with FVB/NJ or B6.FVB-Sicd1 congenic mice. A survey of Galr1 expression among other inbred strains showed a significant effect such that 'susceptible' strains showed a reduction in Galr1 expression as compared with 'resistant' strains. In contrast, no differences in Mbp expression were observed. In summary, these results suggest that differential expression of Galr1 may contribute to the differences in susceptibility to seizure-induced cell death between cell death-resistant and cell death-susceptible strains.
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Affiliation(s)
- S Kong
- Department of Biochemistry and Molecular Biology, University of Southern California Keck School of Medicine, Los Angeles, CA, USA
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66
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Bulaj G, Green BR, Lee HK, Robertson CR, White K, Zhang L, Sochanska M, Flynn SP, Scholl EA, Pruess TH, Smith MD, White HS. Design, Synthesis, and Characterization of High-Affinity, Systemically-Active Galanin Analogues with Potent Anticonvulsant Activities. J Med Chem 2008; 51:8038-47. [DOI: 10.1021/jm801088x] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Grzegorz Bulaj
- Department of Medicinal Chemistry, Department of Pharmacology and Toxicology, College of Pharmacy, University of Utah, Salt Lake City, Utah 84108
| | - Brad R. Green
- Department of Medicinal Chemistry, Department of Pharmacology and Toxicology, College of Pharmacy, University of Utah, Salt Lake City, Utah 84108
| | - Hee-Kyoung Lee
- Department of Medicinal Chemistry, Department of Pharmacology and Toxicology, College of Pharmacy, University of Utah, Salt Lake City, Utah 84108
| | - Charles R. Robertson
- Department of Medicinal Chemistry, Department of Pharmacology and Toxicology, College of Pharmacy, University of Utah, Salt Lake City, Utah 84108
| | - Karen White
- Department of Medicinal Chemistry, Department of Pharmacology and Toxicology, College of Pharmacy, University of Utah, Salt Lake City, Utah 84108
| | - Liuyin Zhang
- Department of Medicinal Chemistry, Department of Pharmacology and Toxicology, College of Pharmacy, University of Utah, Salt Lake City, Utah 84108
| | - Marianna Sochanska
- Department of Medicinal Chemistry, Department of Pharmacology and Toxicology, College of Pharmacy, University of Utah, Salt Lake City, Utah 84108
| | - Sean P. Flynn
- Department of Medicinal Chemistry, Department of Pharmacology and Toxicology, College of Pharmacy, University of Utah, Salt Lake City, Utah 84108
| | - Erika Adkins Scholl
- Department of Medicinal Chemistry, Department of Pharmacology and Toxicology, College of Pharmacy, University of Utah, Salt Lake City, Utah 84108
| | - Timothy H. Pruess
- Department of Medicinal Chemistry, Department of Pharmacology and Toxicology, College of Pharmacy, University of Utah, Salt Lake City, Utah 84108
| | - Misty D. Smith
- Department of Medicinal Chemistry, Department of Pharmacology and Toxicology, College of Pharmacy, University of Utah, Salt Lake City, Utah 84108
| | - H. Steve White
- Department of Medicinal Chemistry, Department of Pharmacology and Toxicology, College of Pharmacy, University of Utah, Salt Lake City, Utah 84108
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Bialer M, Johannessen SI, Levy RH, Perucca E, Tomson T, White HS. Progress report on new antiepileptic drugs: a summary of the Ninth Eilat Conference (EILAT IX). Epilepsy Res 2008; 83:1-43. [PMID: 19008076 DOI: 10.1016/j.eplepsyres.2008.09.005] [Citation(s) in RCA: 157] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2008] [Revised: 09/07/2008] [Accepted: 09/15/2008] [Indexed: 12/18/2022]
Abstract
The Ninth Eilat Conference on New Antiepileptic Drugs (AEDs)-EILAT IX, took place in Sitges, Barcelona from the 15th to 19th of June 2008. Over 300 basic scientists, clinical pharmacologists and neurologists from 25 countries attended the conference, whose main themes included old and new AEDs in generalized epilepsies, novel formulations and routes of administration of AEDs, common targets and mechanisms of action of drugs for treating epilepsy and other central nervous system (CNS) disorders, and opportunities and perspectives in new AED discovery. Consistent with previous formats of this conference, a large part of the programme was devoted to a review of AEDs in development, as well as updates on AEDs introduced since 1989. Unlike previous EILAT manuscripts, the current (EILAT IX) manuscript focuses only on the preclinical and clinical pharmacology of AEDs that are currently in development. These include brivaracetam, carisbamate (RWJ-333369), 2-deoxy-d-glucose, eslicarbazepine acetate (BIA-2-093), ganaxolone, huperzine, JZP-4, lacosamide, NAX-5055, propylisopropylacetamide (PID), retigabine, T-2000, tonabersat, valrocemide and YKP-3089. The CNS efficacy of these compounds in anticonvulsant animal models as well as other disease model systems are presented in first and second tables and their proposed mechanisms of action are summarized in the third table.
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Affiliation(s)
- Meir Bialer
- Department of Pharmaceutics, School of Pharmacy and David R. Bloom Centre for Pharmacy, Faculty of Medicine, Ein Karem, The Hebrew University of Jerusalem, 91120 Jerusalem, Israel.
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68
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Abstract
Galanin (GAL) and GAL receptors (GALRs) are overexpressed in degenerating brain regions associated with cognitive decline in Alzheimer's disease (AD). The functional consequences of GAL plasticity in AD are unclear. GAL inhibits cholinergic transmission in the hippocampus and impairs spatial memory in rodent models, suggesting GAL overexpression exacerbates cognitive impairment in AD. By contrast, gene expression profiling of individual cholinergic basal forebrain (CBF) neurons aspirated from AD tissue revealed that GAL hyperinnervation positively regulates mRNAs that promote CBF neuronal function and survival. GAL also exerts neuroprotective effects in rodent models of neurotoxicity. These data support the growing concept that GAL overexpression preserves CBF neuron function which in turn may slow the onset of AD symptoms. Further elucidation of GAL activity in selectively vulnerable brain regions will help gauge the therapeutic potential of GALR ligands for the treatment of AD.
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Affiliation(s)
- S. E. Counts
- Department of Neurological Sciences, Rush University Medical Center, 1735 West Harrison Street Suite 300, Chicago, Ilinois 60612 USA
| | - S. E. Perez
- Department of Neurological Sciences, Rush University Medical Center, 1735 West Harrison Street Suite 300, Chicago, Ilinois 60612 USA
| | - E. J. Mufson
- Department of Neurological Sciences, Rush University Medical Center, 1735 West Harrison Street Suite 300, Chicago, Ilinois 60612 USA
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69
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Mazarati A, Wu J, Shin D, Kwon YS, Sankar R. Antiepileptogenic and antiictogenic effects of retigabine under conditions of rapid kindling: an ontogenic study. Epilepsia 2008; 49:1777-86. [PMID: 18503560 DOI: 10.1111/j.1528-1167.2008.01674.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
PURPOSE To examine antiepileptogenic and antiictogenic potential of retigabine (RTG) under conditions of rapid kindling epileptogenesis during different stages of development. METHODS The experiments were performed in postnatal day 14 (P14), P21, and P35 male Wistar rats. After stereotaxic implantation of hippocampal stimulating and recording electrodes, the effects of RTG on baseline afterdischarge (AD) properties were studied. Next, the animals underwent rapid kindling (sixty 10 s trains, bipolar 20 Hz square wave pulses delivered every 5 min). The progression of seizures (kindling acquisition), and responses to test stimulations after kindling (retention) were compared between RTG and vehicle-treated rats. Additionally, the effects of RTG on the severity of seizures in previously kindled animals were examined. RESULTS When administered intraperitoneally in doses that induced only mild, or no motor deficits, RTG significantly dampened brain excitability, evident as the increase of AD threshold and shortening of AD duration. During kindling, RTG delayed the development of focal seizures in P14 rats, and prevented the occurrence of full limbic seizures at all three ages. At P14 and P21, but not at P35, pretreatment with RTG prevented the establishment of kindling-induced enhanced seizure susceptibility. Administration of RTG to kindled animals decreased the severity of seizures induced by test stimulation. The effect was most prominent at P14. DISCUSSION RTG exerted both antiepileptogenic and antiictogenic effects under conditions of rapid kindling model. These effects were apparent during postneonatal, early childhood, and adolescent stages of development.
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Affiliation(s)
- Andréy Mazarati
- Department of Pediatrics, Neurology Division, David Geffen School of Medicine at UCLA, Los Angeles, California 90095-1752, USA.
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Kanter-Schlifke I, Toft Sørensen A, Ledri M, Kuteeva E, Hökfelt T, Kokaia M. Galanin gene transfer curtails generalized seizures in kindled rats without altering hippocampal synaptic plasticity. Neuroscience 2007; 150:984-92. [DOI: 10.1016/j.neuroscience.2007.09.056] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2007] [Revised: 09/10/2007] [Accepted: 09/28/2007] [Indexed: 11/26/2022]
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Abstract
1. In recent decades evidence has accumulated demonstrating the birth and functional integration of new neurons in specific regions of the adult mammalian brain, including the dentate gyrus of the hippocampus and the subventricular zone. 2. Studies in a variety of models have revealed genetic, environmental and pharmacological factors that regulate adult neurogenesis. The present review examines some of the molecular and cellular mechanisms that could be mediating these regulatory effects in both the normal and dysfunctional brain. 3. The dysregulation of adult neurogenesis may contribute to the pathogenesis of neurodegenerative disorders, such as Huntington's, Alzheimer's and Parkinson's disease, as well as psychiatric disorders such as depression. Recent evidence supports this idea and, furthermore, also indicates that factors promoting neurogenesis can modify the onset and progression of specific brain disorders, including Huntington's disease and depression.
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Affiliation(s)
- Helen E Grote
- University Laboratory of Physiology, University of Oxford, Oxford, United Kingdom
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Mazarati A, Shin D, Auvin S, Caplan R, Sankar R. Kindling epileptogenesis in immature rats leads to persistent depressive behavior. Epilepsy Behav 2007; 10:377-83. [PMID: 17368107 PMCID: PMC1958957 DOI: 10.1016/j.yebeh.2007.02.001] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/09/2007] [Revised: 02/06/2007] [Accepted: 02/07/2007] [Indexed: 11/30/2022]
Abstract
Depression is a frequent comorbidity in epilepsy patients. A variety of biological factors may underlie epilepsy-associated depression. We examined whether kindling-induced chronic increase in seizure susceptibility is accompanied by behavioral symptoms of depression. Three-week-old Wistar rats underwent rapid kindling: 84 initially subconvulsant electrical stimulations of ventral hippocampus delivered every 5 minutes, followed by depression-specific behavioral tests performed 2 and 4 weeks later. Kindled animals exhibited a sustained increase in immobility time in the forced swim test and the loss of taste preference toward calorie-free saccharin, as compared with controls. Initial loss of preference toward the intake of calorie-containing sucrose was followed by the increased consumption at 4 weeks. At both time points, animals exhibited enhanced seizure susceptibility on test stimulations of the hippocampus. We conclude that neuronal plastic changes associated with the kindling state are accompanied by the development of depressive behavior.
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Affiliation(s)
- Andréy Mazarati
- Department of Pediatrics, David Geffen School of Medicine at UCLA, Room 22-474 MDCC, Los Angeles, CA 90095-1752, USA.
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