1
|
Pedersen S, Kverneland M, Nakken KO, Rudi K, Iversen PO, Gervin K, Selmer KK. Genome-wide decrease in DNA methylation in adults with epilepsy treated with modified ketogenic diet: A prospective study. Epilepsia 2022; 63:2413-2426. [PMID: 35762681 PMCID: PMC9796519 DOI: 10.1111/epi.17351] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Revised: 06/27/2022] [Accepted: 06/27/2022] [Indexed: 01/01/2023]
Abstract
OBJECTIVE The aim of this study was to investigate the impact of the modified ketogenic diet on DNA methylation in adults with epilepsy. METHODS In this prospective study, we investigated the genome-wide DNA methylation in whole blood in 58 adults with epilepsy treated with the modified ketogenic for 12 weeks. Patients were recruited from the National Center for Epilepsy, Norway, from March 1, 2011 to February 28, 2017. DNA methylation was analyzed using the Illumina Infinium MethylationEPIC BeadChip array. Analysis of variance and paired t-test were used to identify differentially methylated loci after 4 and 12 weeks of dietary treatment. A false discovery rate approach with a significance threshold of <5% was used to adjust for multiple comparisons. RESULTS We observed a genome-wide decrease in DNA methylation, both globally and at specific sites, after 4 and 12 weeks of dietary treatment. A substantial share of the differentially methylated positions (CpGs) were annotated to genes associated with epilepsy (n = 7), lipid metabolism (n = 8), and transcriptional regulation (n = 10). Furthermore, five of the identified genes were related to inositol phosphate metabolism, which may represent a possible mechanism by which the ketogenic diet attenuates seizures. SIGNIFICANCE A better understanding of the modified ketogenic diet's influence at the molecular level may be the key to unraveling the mechanisms by which the diet can ameliorate seizures and possibly to identifying novel therapeutic targets for epilepsy.
Collapse
Affiliation(s)
- Sigrid Pedersen
- National Center for EpilepsyOslo University HospitalOsloNorway
| | | | | | - Knut Rudi
- Department of Chemistry, Biotechnology, and Food ScienceNorwegian University of Life SciencesÅsNorway
| | - Per Ole Iversen
- Department of NutritionUniversity of OsloOsloNorway,Department of HematologyOslo University HospitalOsloNorway
| | - Kristina Gervin
- Department of Research and InnovationOslo University HospitalOsloNorway
| | - Kaja Kristine Selmer
- National Center for EpilepsyOslo University HospitalOsloNorway,Department of Research and InnovationOslo University HospitalOsloNorway
| |
Collapse
|
2
|
Thomas MP, Mills SJ, Potter BVL. The "Other" Inositols and Their Phosphates: Synthesis, Biology, and Medicine (with Recent Advances in myo-Inositol Chemistry). Angew Chem Int Ed Engl 2016; 55:1614-50. [PMID: 26694856 PMCID: PMC5156312 DOI: 10.1002/anie.201502227] [Citation(s) in RCA: 112] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2015] [Indexed: 12/24/2022]
Abstract
Cell signaling via inositol phosphates, in particular via the second messenger myo-inositol 1,4,5-trisphosphate, and phosphoinositides comprises a huge field of biology. Of the nine 1,2,3,4,5,6-cyclohexanehexol isomers, myo-inositol is pre-eminent, with "other" inositols (cis-, epi-, allo-, muco-, neo-, L-chiro-, D-chiro-, and scyllo-) and derivatives rarer or thought not to exist in nature. However, neo- and d-chiro-inositol hexakisphosphates were recently revealed in both terrestrial and aquatic ecosystems, thus highlighting the paucity of knowledge of the origins and potential biological functions of such stereoisomers, a prevalent group of environmental organic phosphates, and their parent inositols. Some "other" inositols are medically relevant, for example, scyllo-inositol (neurodegenerative diseases) and d-chiro-inositol (diabetes). It is timely to consider exploration of the roles and applications of the "other" isomers and their derivatives, likely by exploiting techniques now well developed for the myo series.
Collapse
Affiliation(s)
- Mark P Thomas
- Department of Pharmacy & Pharmacology, University of Bath, Claverton Down, Bath, BA2 7AY, UK
| | - Stephen J Mills
- Department of Pharmacy & Pharmacology, University of Bath, Claverton Down, Bath, BA2 7AY, UK
| | - Barry V L Potter
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford, OX1 3QT, UK.
| |
Collapse
|
3
|
Thomas MP, Mills SJ, Potter BVL. Die “anderen” Inositole und ihre Phosphate: Synthese, Biologie und Medizin (sowie jüngste Fortschritte in dermyo-Inositolchemie). Angew Chem Int Ed Engl 2015. [DOI: 10.1002/ange.201502227] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Mark P. Thomas
- Department of Pharmacy & Pharmacology; University of Bath; Claverton Down Bath BA2 7AY Vereinigtes Königreich
| | - Stephen J. Mills
- Department of Pharmacy & Pharmacology; University of Bath; Claverton Down Bath BA2 7AY Vereinigtes Königreich
| | - Barry V. L. Potter
- Department of Pharmacology; University of Oxford; Mansfield Road Oxford OX1 3QT Vereinigtes Königreich
| |
Collapse
|
4
|
Zhang XY, Yang ZY, Li JM, Li HX, Wang L, Gong QY, Zhou D. Longitudinal ¹H MRS assessment of the thalamus in a Coriaria lactone-induced rhesus monkey status epilepticus model. NMR IN BIOMEDICINE 2012; 25:1196-201. [PMID: 22389048 DOI: 10.1002/nbm.2789] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2011] [Revised: 12/03/2011] [Accepted: 01/15/2012] [Indexed: 02/05/2023]
Abstract
Neurophysiological, biochemical and anatomical evidence implicates the thalamus as playing a role in epileptic seizures. Until recently, however, longitudinal characterization of in vivo thalamus dynamics had not been reported. In this study, we investigated the metabolism in the thalamus to identify the changes that occur following Coriaria lactone (CL)-induced status epilepticus (SE) and to observe whether the epileptiform discharges could present a difference between the left and right thalami. Five rhesus monkeys underwent whole-brain MRI and single-voxel MRS on a Siemens Trio Tim 3-T MR scanner with a 12-channel head coil. Spectra were processed using LCModel. Scans were performed in five animals before SE and at 1, 7, 21 and 42 days after the onset of SE. Statistical analysis of the data obtained demonstrated no significant difference in the bilateral thalamus of healthy macaques. Our MRS data showed symmetrical distributions of N-acetylaspartate in the right and left thalami after SE (p = 0.003). In addition, this longitudinal study demonstrated elevated glutamate/glutamine (p < 0.05) and reduced myo-inositol (p < 0.05) in the bilateral thalamus 1 day after SE, and all metabolites approached their baseline levels by the fifth scan. Our results demonstrate that metabolic changes occur in the thalamus during CL-induced SE in rhesus monkeys. The various metabolic changes may indicate that the left thalamus is more vulnerable to epileptic strike.
Collapse
Affiliation(s)
- Xiao-Yun Zhang
- Department of Neurology, West China Hospital of Sichuan University, Chengdu, China
| | | | | | | | | | | | | |
Collapse
|
5
|
Rowley NM, Smith MD, Lamb JG, Schousboe A, White HS. Hippocampal betaine/GABA transporter mRNA expression is not regulated by inflammation or dehydration post-status epilepticus. J Neurochem 2011; 117:82-90. [PMID: 21219332 DOI: 10.1111/j.1471-4159.2011.07174.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Seizure activity can alter GABA transporter and osmoprotective gene expression, which may be involved in the pathogenesis of epilepsy. However, the response of the betaine/GABA transporter (BGT1) is unknown. The goal of the present study was to compare the expression of BGT1 mRNA to that of other osmoprotective genes and GABA transporters following status epilepticus (SE). The possible contributory role of dehydration and inflammation was also investigated because both have been shown to be involved in the regulation of GABA transporter and/or osmoprotective gene expression. BGT1 mRNA was increased 24 h post-SE, as were osmoprotective genes. BGT1 was decreased 72 h and 4 weeks post-SE, as were the GABA transporter mRNAs. The mRNA values for osmoprotective genes following 24-h water withdrawal were significantly lower than the values obtained 24 h post-SE despite similarities in their plasma osmolality values. BGT1 mRNA was not altered by lipopolysaccharide-induced inflammation while the transcription factor tonicity-responsive enhancer binding protein and the GABA transporters 1 and 3 were. These results suggest that neither plasma osmolality nor inflammation fully account for the changes seen in BGT1 mRNA expression post-SE. However, it is evident that BGT1 mRNA expression is altered by SE and displays a temporal pattern with similarities to both GABA and osmolyte transporters. Further investigation of BGT1 regulation in the brain is warranted.
Collapse
Affiliation(s)
- Nicole M Rowley
- Anticonvulsant Drug Development Program, Department of Pharmacology Toxicology, University of Utah, Salt Lake City, Utah 84108, USA
| | | | | | | | | |
Collapse
|
6
|
Azab AN, Agam G, Kaplanski J, Delbar V, Greenberg ML. Inositol depletion: a good or bad outcome of valproate treatment? FUTURE NEUROLOGY 2008. [DOI: 10.2217/14796708.3.3.275] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Bipolar affective disorder is a severe and chronic disabling illness affecting 1.5% of the general population. Lithium, valproate and other mood stabilizers are used to treat bipolar disorder; however, these are ineffective for, and not tolerated by, a significant percentage of patients, underscoring the urgent need for better medications. Although not universally accepted, the inositol-depletion hypothesis is one of the main hypotheses suggested to explain the therapeutic mechanism of mood-stabilizing drugs. This paper reviews the relevance of the inositol-depletion hypothesis, paying special attention to the inhibition of inositol de novo synthesis by valproate. It also discusses inositol supplementation as a treatment strategy for multiple neurological disorders, including prophylactic use against valproate-induced neural tube defects.
Collapse
Affiliation(s)
- Abed N Azab
- Ben-Gurion University of the Negev, School for Community Health Professions, Faculty of Health Sciences, PO Box 653, Beer-Sheva 84105, Israel
| | - Galila Agam
- Ben-Gurion University of the Negev, Psychiatry Research Unit & Department of Clinical Biochemistry, Faculty of Health Sciences, PO Box 4600, Beer-Sheva 84170, Israel
| | - Jacob Kaplanski
- Ben-Gurion University of the Negev, Department of Clinical Pharmacology, Faculty of Health Sciences, PO Box 653, Beer-Sheva 84105, Israel
| | - Vered Delbar
- Ben-Gurion University of the Negev, School for Community Health Professions, Faculty of Health Sciences, PO Box 653, Beer-Sheva 84105, Israel
| | - Miriam L Greenberg
- Wayne State University, Department of Biological Sciences, Detroit, MI 48202, USA
| |
Collapse
|
7
|
Belmaker RH, Bersudsky Y. Lithium–pilocarpine seizures as a model for lithium action in mania. Neurosci Biobehav Rev 2007; 31:843-9. [PMID: 17602744 DOI: 10.1016/j.neubiorev.2007.05.001] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2006] [Revised: 05/08/2007] [Accepted: 05/09/2007] [Indexed: 10/23/2022]
Abstract
Lithium (Li) pre-treatment of rats or mice given low dose pilocarpine induces a unique limbic seizure syndrome. This syndrome is stereospecifically reversed by myo-inositol, which suggests that it is a behavioral model for Li depletion of brain inositol. However, this syndrome has little face validity because seizures are not a component of bipolar disorder. Moreover, other animal species that maintain higher brain inositol levels than mice or rats do not show Li-pilocarpine seizures and a study in humans suggests that humans do not show this syndrome as well. It could be suggested that Li-pilocarpine seizures are an in vivo bioassay for inositol depletion. Recent studies of knockout mice lacking inositol monophosphatase-1 or the sodium myo-inositol transporter-1 found that both these knockout mice given pilocarpine develop limbic seizures as if they had been pre-treated with Li. These mice in addition to such pilocarpine sensitivity have other behaviors such as decreased immobility in the Porsolt forced swim test that suggests that their inositol depletion has Li-like effects. Thus, the Li-pilocarpine seizure model may, despite its lack of face validity, be a biochemical marker for a model of mania treatment in animals.
Collapse
Affiliation(s)
- R H Belmaker
- Ben Gurion University of the Negev, Beersheva Mental Health Center, P.O. Box 4600, Beersheva, Israel.
| | | |
Collapse
|
8
|
Riederer F, Bittsanský M, Schmidt C, Mlynárik V, Baumgartner C, Moser E, Serles W. 1H magnetic resonance spectroscopy at 3 T in cryptogenic and mesial temporal lobe epilepsy. NMR IN BIOMEDICINE 2006; 19:544-53. [PMID: 16521092 DOI: 10.1002/nbm.1029] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
The objectives of this work were to compare concentrations of N-acetylaspartate (NAA), glutamate (Glu), glutamine (Gln), Glx (=Glu + Gln), myo-inositol (mI), total creatine (Cre) and other metabolites in the temporal lobes of patients with mesial temporal lobe epilepsy (mTLE), cryptogenic TLE (cTLE), who show no abnormalities in high-resolution MRI, and healthy controls using single voxel (1)H MRS at 3 T. Twelve patients with mTLE, nine with cTLE and 22 controls were investigated using a short echo time STEAM protocol. Voxels were positioned bilaterally in the medial and lateral temporal lobes. Spectra were processed with LCModel. Significantly lower mean NAA were detected in mTLE patients (P < 0.001) and a trend towards lower NAA in cTLE patients compared to controls (P = 0.053). Glx was not different between groups. Estimates of Glu showed a different metabolic pattern in mTLE with elevated Glu in lateral compared with medial voxels on the ipsilateral side to seizure onset (P = 0.019). MI concentrations were significantly lower in cTLE (P < 0.001) and in mTLE patients (P = 0.005) compared with healthy controls. MI/Cre was significantly reduced in cTLE patients only (P = 0.004). The results confirm low NAA in mTLE and to a lesser extent in cTLE patients. MI and mI/Cre were identified as potential metabolic indicators of the epileptogenic area in cTLE.
Collapse
Affiliation(s)
- Franz Riederer
- Universitätsklinik für Neurologie, Abteilung für Klinische Epilepsieforschung, Medizinische Universität Wien, A-1090 Vienna, Austria
| | | | | | | | | | | | | |
Collapse
|
9
|
Einat H, Manji HK. Cellular plasticity cascades: genes-to-behavior pathways in animal models of bipolar disorder. Biol Psychiatry 2006; 59:1160-71. [PMID: 16457783 DOI: 10.1016/j.biopsych.2005.11.004] [Citation(s) in RCA: 102] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/22/2005] [Revised: 11/11/2005] [Accepted: 11/17/2005] [Indexed: 11/28/2022]
Abstract
BACKGROUND Despite extensive research, the molecular/cellular underpinnings of bipolar disorder (BD) remain to be fully elucidated. Recent data has demonstrated that mood stabilizers exert major effects on signaling that regulate cellular plasticity; however, a direct extrapolation to mechanisms of disease demands proof that manipulation of candidate genes, proteins, or pathways result in relevant behavioral changes. METHODS We critique and evaluate the behavioral changes induced by manipulation of cellular plasticity cascades implicated in BD. RESULTS Not surprisingly, the behavioral data suggest that several important signaling molecules might play important roles in mediating facets of the complex symptomatology of BD. Notably, the protein kinase C and extracellular signal-regulated kinase cascades might play important roles in the antimanic effects of mood stabilizers, whereas glycogen synthase kinase (GSK)-3 might mediate facets of lithium's antimanic/antidepressant actions. Glucocorticoid receptor (GR) modulation also seems to be capable to inducing affective-like changes observed in mood disorders. And Bcl-2, amino-3-hydroxy-5-methylisoxazole-4-propionic acid receptors, and inositol homeostasis represent important pharmacological targets for mood stabilizers, but additional behavioral research is needed to more fully delineate their behavioral effects. CONCLUSIONS Behavioral data support the notion that regulation of cellular plasticity is involved in affective-like behavioral changes observed in BD. These findings are leading to the development of novel therapeutics for this devastating illness.
Collapse
Affiliation(s)
- Haim Einat
- College of Pharmacy, Duluth, University of Minnesota, 55812, USA.
| | | |
Collapse
|
10
|
Shaldubina A, Einat H, Bersudsky Y, Belmaker RH. Epi-inositol is ineffective in Porsolt Forced Swim Test model of depression. Neuropsychiatr Dis Treat 2005; 1:189-90. [PMID: 18568066 PMCID: PMC2413201 DOI: 10.2147/nedt.1.2.189.61052] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Affiliation(s)
- Alona Shaldubina
- Stanley Center for Bipolar Research, Faculty of Health Sciences, Ben-Gurion University of the Negev Beer-Sheva, Israel.
| | | | | | | |
Collapse
|
11
|
Vitelio C, Bellomo A, Brovetto M, Seoane G, Gonzalez D. Concise chemoenzymatic synthesis of epi-inositol. Carbohydr Res 2004; 339:1773-8. [PMID: 15220087 DOI: 10.1016/j.carres.2004.04.011] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2003] [Accepted: 04/15/2004] [Indexed: 11/25/2022]
Abstract
epi-Inositol was synthesized in six steps in 40% overall yield from a bacterial bromobenzene metabolite. The chemoenzymatic route involved toluene dioxygenase oxidation, substrate-directed catalytic osmylation, m-CPBA epoxidation, radical debromination, and Amberlite-catalized hydrolysis. The route described is amenable to scaleup and could allow access to cis-inositol, and deoxy derivatives of epi-inositol.
Collapse
Affiliation(s)
- Cecilia Vitelio
- Departamento de Química Orgánica, Facultad de Química, Universidad de la República, C.C. 1157, Montevideo, Uruguay
| | | | | | | | | |
Collapse
|
12
|
Shaldubina A, Ju S, Vaden DL, Ding D, Belmaker RH, Greenberg ML. Epi-inositol regulates expression of the yeast INO1 gene encoding inositol-1-P synthase. Mol Psychiatry 2002; 7:174-80. [PMID: 11840310 DOI: 10.1038/sj.mp.4000965] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/26/2001] [Revised: 06/21/2001] [Accepted: 06/27/2001] [Indexed: 11/08/2022]
Abstract
Myo-inositol exerts behavioral effects in animal models of psychiatric disorders and is effective in clinical trials in psychiatric patients. Interestingly, epi-inositol exerts behavioral effects similar to myo-inositol, even though epi-inositol is not a substrate for synthesis of phosphatidylinositol. We postulated that the behavioral effects of epi-inositol may be due to its effects on gene expression. Yeast INO1expression was measured in northern blots. INM1 was determined by beta-galactosidase activity in a strain containing the fusion gene INM1-lacZintegrated into the genome. Epi-inositol affects regulation of expression of the INO1 gene (encoding inositol-1-P synthase), even though it cannot support growth of an inositol auxotroph (suggesting that, as in mammalian cells, it is not incorporated into phosphatidylinositol). Like myo-inositol, although to a lesser extent, epi-inositol causes a significant reduction in INO1 expression, and reverses the lithium- or valproate-induced increase in INO1 expression. However, it does not affect regulation of INM1 (encoding inositol monophosphatase), the expression of which is up-regulated by myo-inositol. The observed regulatory effects of epi-inositol on expression of the most highly regulated gene in the inositol biosynthetic pathway may help to explain how this inositol isomer can exert behavioral effects without being incorporated into phosphatidylinositol.
Collapse
Affiliation(s)
- A Shaldubina
- Zlotowski Center for Neuroscience, Faculty of Health Sciences, Ben Gurion University of the Negev, Beersheva, Israel
| | | | | | | | | | | |
Collapse
|
13
|
|
14
|
Bersudsky Y, Einat H, Stahl Z, Belmaker RH. Epi-inositol and inositol depletion: two new treatment approaches in affective disorder. Curr Psychiatry Rep 1999; 1:141-7. [PMID: 11122916 DOI: 10.1007/s11920-999-0023-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Inositol is a simple polyol precursor in a second messenger system important in brain myo-insitol, the natural isomer, which has been found to be therapeutically effective in depression, panic disorder, and obsessive-compulsive disorder in double-blind controlled trials. Recently, epi-inositol, an unnatural stereoisomer of myo-inositol, was found to have effects similar to those of myo-inositol to reverse lithium-pilocarpine seizures. We measured the behavior of rats in an elevated plus maze model of anxiety after chronic treatment of 11 daily intraperitoneal injections of epi-inositol, myo-inositol, or control solution. Epi-inositol reduced anxiety levels of rats compared with controls, and its effect was stronger than that of myo- inositol. Lithium has been hypothesized to alleviate mania by reducing brain inositol levels. Inositol in brain derives from the second messenger cycle, from new synthesis, or from diet via transport across the blood brain barrier. Because the first two are inhibited by lithium, we propose that an inositol-free diet will augment lithium action in mania by enhancing restriction of inositol.
Collapse
Affiliation(s)
- Y Bersudsky
- Beer-Sheba Mental Health Center, PO Box 4600, Beer-Sheba, Israel
| | | | | | | |
Collapse
|
15
|
Kofman O, Patishi Y. Interactions of lithium and drugs that affect signal transduction on behaviour in rats. Eur Neuropsychopharmacol 1999; 9:385-97. [PMID: 10523045 DOI: 10.1016/s0924-977x(99)00009-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The therapeutic mechanism of the action of lithium in the treatment of bipolar affective disorder is not known, in spite of a burgeoning number of biochemical studies linking lithium to signal transduction processes. This article reviews a decade of studies examining the behavioural manifestations of manipulating inositol, cyclic adenosine monophosphate (cAMP) and G proteins in rats. Inositol, forskolin, dibutyryl cAMP and pertussis toxin all interacted with lithium when rearing behavior was measured. Lithium potentiated the increase in locomotion induced by injections of cholera toxin into the nucleus accumbens, consistent with the hypothesis that it inactivates inhibitory G proteins. More specific interactions were found between lithium and inositol following cholinergic and serotonergic stimulation. Inositol, but not forskolin, attenuated lithium-pilocarpine seizures and the enhancement of the serotonin syndrome; however, inositol had no effect on lithium-induced attenuation of wet dog shakes following an injection of 5-hydroxytryptophan. Behavioural evidence supports biochemical findings suggesting that lithium's interactions with the phoshphatidyl inositol and cyclic AMP signal transduction systems may be relevant to its therapeutic effects in bipolar disorder. Further research on more specific behaviours may elucidate the relevant pharmacological mechanisms underlying the therapeutic effect of lithium.
Collapse
Affiliation(s)
- O Kofman
- Department of Behavioral Sciences, Faculty of Social Sciences and Humanities, Ben-Gurion University of the Negev, Beer-Sheva, Israel.
| | | |
Collapse
|
16
|
Nonaka M, Kohmura E, Yamashita T, Yamauchi A, Fujinaka T, Yoshimine T, Tohyama M, Hayakawa T. Kainic acid-induced seizure upregulates Na(+)/myo-inositol cotransporter mRNA in rat brain. BRAIN RESEARCH. MOLECULAR BRAIN RESEARCH 1999; 70:179-86. [PMID: 10407166 DOI: 10.1016/s0169-328x(99)00127-8] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
A major organic osmolyte, myo-inositol protects cells from perturbing effects of high intracellular concentrations of electrolytes. Myo-inositol is accumulated into cells through Na(+)/myo-inositol cotransporter (SMIT). In order to investigate the regulation of SMIT in generalized seizure, we employed Northern blot analysis and in situ hybridization to study the changes in SMIT mRNA expression in kainic acid-injected rats. Northern blot analysis demonstrated that SMIT mRNA began to increase in the brain 2 h after onset of seizure, and peaked at 12 h. In situ hybridization revealed rapid increase of SMIT mRNA (2 h of seizure) in the CA3 hippocampal pyramidal cells and in the dentate granular cells. Then, at 4-6 h SMIT mRNA expression was observed in the other limbic structure such as amygdala and piriform cortex. Finally, in neocortex and in CA1 pyramidal cells, SMIT mRNA was slowly increased and peaked at 12 h. Microautoradiogram demonstrated that cells expressed SMIT mRNA were mainly neurons. These results suggest that SMIT mRNA is upregulated by kainic acid-induced seizure primarily in structures involved in seizure activity.
Collapse
Affiliation(s)
- M Nonaka
- Department of Neurosurgery, Osaka University School of Medicine, 2-2 Yamadaoka, Suita, Osaka, 565-0871, Japan.
| | | | | | | | | | | | | | | |
Collapse
|
17
|
Richards MH, Belmaker RH. Epi-inositol is biochemically active in reversing lithium effects on cytidine monophosphorylphosphatidate (CMP-PA). Short communication. J Neural Transm (Vienna) 1996; 103:1281-5. [PMID: 9013414 DOI: 10.1007/bf01271188] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
In CHOm3 cells and rat cerebral cortex slices, epi-inositol was less potent but as effective as myo-inositol in reversing carbachol/lithium-stimulated CMP-PA accumulation whereas L-chiro- and scyllo-inositol were less active or inactive. These results with the four inositol isomers in two tissues correlate exactly with their effects on lithium-pilocarpine induced seizures and suggest a common mechanism of action for biochemical and behavioural effects.
Collapse
Affiliation(s)
- M H Richards
- Marion Merrell Research Institute, Strasbourg, France
| | | |
Collapse
|