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Keil MF, Briassoulis G, Stratakis CA. The Role of Protein Kinase A in Anxiety Behaviors. Neuroendocrinology 2016; 103:625-39. [PMID: 26939049 DOI: 10.1159/000444880] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/27/2015] [Accepted: 02/19/2016] [Indexed: 11/19/2022]
Abstract
This review focuses on the genetic and other evidence supporting the notion that the cyclic AMP (cAMP) signaling pathway and its mediator, the protein kinase A (PKA) enzyme, which respond to environmental stressors and regulate stress responses, are central to the pathogenesis of disorders related to anxiety. We describe the PKA pathway and review in vitro animal studies (mouse) and other evidence that support the importance of PKA in regulating behaviors that lead to anxiety. Since cAMP signaling and PKA have been pharmacologically exploited since the 1940s (even before the identification of cAMP as a second messenger with PKA as its mediator) for a number of disorders from asthma to cardiovascular diseases, there is ample opportunity to develop therapies using this new knowledge about cAMP, PKA, and anxiety disorders.
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Affiliation(s)
- Margaret F Keil
- Section on Endocrinology and Genetics, Program in Developmental Endocrinology and Genetics, Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), National Institutes of Health, Bethesda, Md., USA
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Featherstone RE, McMullen MF, Ward KR, Bang J, Xiao J, Siegel SJ. EEG biomarkers of target engagement, therapeutic effect, and disease process. Ann N Y Acad Sci 2015; 1344:12-26. [DOI: 10.1111/nyas.12745] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Affiliation(s)
- Robert E. Featherstone
- Translational Neuroscience Program; Department of Psychiatry; University of Pennsylvania; Philadelphia Pennsylvania
| | - Mary F. McMullen
- Translational Neuroscience Program; Department of Psychiatry; University of Pennsylvania; Philadelphia Pennsylvania
| | - Katelyn R. Ward
- Translational Neuroscience Program; Department of Psychiatry; University of Pennsylvania; Philadelphia Pennsylvania
| | - Jakyung Bang
- Translational Neuroscience Program; Department of Psychiatry; University of Pennsylvania; Philadelphia Pennsylvania
| | - Jane Xiao
- Translational Neuroscience Program; Department of Psychiatry; University of Pennsylvania; Philadelphia Pennsylvania
| | - Steven J. Siegel
- Translational Neuroscience Program; Department of Psychiatry; University of Pennsylvania; Philadelphia Pennsylvania
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Lin RE, Ambler L, Billingslea EN, Suh J, Batheja S, Tatard-Leitman V, Featherstone RE, Siegel SJ. Electroencephalographic and early communicative abnormalities in Brattleboro rats. Physiol Rep 2013; 1:e00100. [PMID: 24303172 PMCID: PMC3841036 DOI: 10.1002/phy2.100] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2013] [Accepted: 08/29/2013] [Indexed: 12/31/2022] Open
Abstract
Reductions in the levels of the neuropeptide vasopressin (VP) and its receptors have been associated with schizophrenia. VP is also critical for appropriate social behaviors in humans as well as rodents. One of the prominent symptoms of schizophrenia is asociality and these symptoms may develop prodromally. A reduction in event-related potential (ERP) peak amplitudes is an endophenotype of schizophrenia. In this study, we use the Brattleboro (BRAT) rat to assess the role of VP deficiency in vocal communication during early development and on auditory ERPs during adulthood. BRAT rats had similar vocal communication to wild-type littermate controls during postnatal days 2 and 5 but the time between vocalizations was increased and the power of the vocalizations was reduced beginning at postnatal day 9. During adulthood, BRAT rats had deficits in auditory ERPs including reduced N40 amplitude and reduced low and high gamma intertrial coherence. These results suggest that the role of VP on vocal communication is an age-dependent process. Additionally, the deficits in ERPs indicate an impairment of auditory information processing related to the reduction in VP. Therefore, manipulation of the VP system could provide a novel mechanism for treatment for negative symptoms of schizophrenia.
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Affiliation(s)
- Robert E Lin
- Department of Psychiatry, Translational Neuroscience Program, School of Medicine, University of Pennsylvania Philadelphia, Pennsylvania
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Animal models and measures of perceptual processing in schizophrenia. Neurosci Biobehav Rev 2013; 37:2092-8. [PMID: 23867801 DOI: 10.1016/j.neubiorev.2013.06.016] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2013] [Revised: 06/16/2013] [Accepted: 06/18/2013] [Indexed: 01/14/2023]
Abstract
This paper summarizes the discussions regarding animal paradigms for assessing perception at the seventh meeting of the Cognitive Neuroscience Treatment Research to Improve Cognition in Schizophrenia (CNTRICS). A breakout group at the meeting addressed candidate tests in animals that might best parallel the human paradigms selected previously in the CNTRICS program to assess two constructs in the domain of perception: gain control and visual integration. The perception breakout group evaluated the degree to which each of the nominated tasks met pre-specified criteria: comparability of tasks across multiple species; construct validity; neuroanatomical homology between species; and dynamic range across parametric variation.
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Collins MT, Singer FR, Eugster E. McCune-Albright syndrome and the extraskeletal manifestations of fibrous dysplasia. Orphanet J Rare Dis 2012; 7 Suppl 1:S4. [PMID: 22640971 PMCID: PMC3359955 DOI: 10.1186/1750-1172-7-s1-s4] [Citation(s) in RCA: 143] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Fibrous dysplasia (FD) is sometimes accompanied by extraskeletal manifestations that can include any combination of café-au-lait macules, hyperfunctioning endocrinopathies, such as gonadotropin-independent precocious puberty, hyperthyroidism, growth hormone excess, FGF23-mediated renal phosphate wasting, and/or Cushing syndrome, as well as other less common features. The combination of any of these findings, with or without FD, is known as McCune-Albright syndrome (MAS). The broad spectrum of involved tissues and the unpredictable combination of findings owe to the fact that molecular defect is due to dominant activating mutations in the widely expressed signaling protein, Gsα, and the fact these mutations arises sporadically, often times early in development, prior to gastrulation, and can distribute across many or few tissues.The complexity can be mastered by a systematic screening of potentially involved tissues and cognizance that the pattern of involved tissues is established, to some degree, in utero. Thorough testing allows the clinician to establish, often times at presentation, the full extent of the disease, and importantly as well what tissues are unaffected. Treatment and follow-up can then be focused on affected systems and a meaningful prognosis can be offered to the patient and family. The authors outline screening and treatment strategies that allow for effective management of the extraskeletal manifestations of FD.
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Affiliation(s)
- Michael T Collins
- Skeletal Clinical Studies Unit, Craniofacial and Skeletal Diseases Branch, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD, USA
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Lazarewicz MT, Ehrlichman RS, Maxwell CR, Gandal MJ, Finkel LH, Siegel SJ. Ketamine Modulates Theta and Gamma Oscillations. J Cogn Neurosci 2010; 22:1452-64. [DOI: 10.1162/jocn.2009.21305] [Citation(s) in RCA: 169] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Abstract
Ketamine, an N-methyl-d-aspartate (NMDA) receptor glutamatergic antagonist, has been studied as a model of schizophrenia when applied in subanesthetic doses. In EEG studies, ketamine affects sensory gating and alters the oscillatory characteristics of neuronal signals in a complex manner. We investigated the effects of ketamine on in vivo recordings from the CA3 region of mouse hippocampus referenced to the ipsilateral frontal sinus using a paired-click auditory gating paradigm. One issue of particular interest was elucidating the effect of ketamine on background network activity, poststimulus evoked and induced activity. We find that ketamine attenuates the theta frequency band in both background activity and in poststimulus evoked activity. Ketamine also disrupts a late, poststimulus theta power reduction seen in control recordings. In the gamma frequency range, ketamine enhances both background and evoked power, but decreases relative induced power. These findings support a role for NMDA receptors in mediating the balance between theta and gamma responses to sensory stimuli, with possible implications for dysfunction in schizophrenia.
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Mouse behavioral endophenotypes for schizophrenia. Brain Res Bull 2010; 83:147-61. [PMID: 20433908 DOI: 10.1016/j.brainresbull.2010.04.008] [Citation(s) in RCA: 125] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2009] [Revised: 12/25/2009] [Accepted: 04/19/2010] [Indexed: 01/20/2023]
Abstract
An endophenotype is a heritable trait that is generally considered to be more highly, associated with a gene-based neurological deficit than a disease phenotype itself. Such, endophenotypic deficits may therefore be observed in the non-affected relatives of disease patients. Once endophenotypes have been established for a given illness, such as schizophrenia, mechanisms of, action may then be established and treatment options developed in order to target such measures. The, current paper describes and assesses the merits and limitations of utilizing behavioral and, electrophysiological endophenotypes of schizophrenia in mice. Such endophenotypic deficits include: decreased auditory event related potential (ERP) amplitude and gating (specifically, that of the P20, N40, P80 and P120); impaired mismatch negativity (MMN); changes in theta and gamma frequency, analyses; decreased pre-pulse inhibition (PPI); impaired working and episodic memories (for instance, novel object recognition [NOR], contextual and cued fear conditioning, latent inhibition, Morris and, radial arm maze identification and nose poke); sociability; and locomotor activity. A variety of, pharmacological treatments, including ketamine, MK-801 and phencyclidine (PCP) can be used to, induce some of the deficits described above, and numerous transgenic mouse strains have been, developed to address the mechanisms responsible for such endophenotypic differences. We also, address the viability and validity of using such measures regarding their potential clinical implications, and suggest several practices that could increase the translatability of preclinical data.
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Breier MR, Lewis B, Shoemaker JM, Light GA, Swerdlow NR. Sensory and sensorimotor gating-disruptive effects of apomorphine in Sprague Dawley and Long Evans rats. Behav Brain Res 2010; 208:560-5. [PMID: 20080128 DOI: 10.1016/j.bbr.2009.12.037] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2009] [Revised: 12/28/2009] [Accepted: 12/31/2009] [Indexed: 11/30/2022]
Abstract
RATIONALE Rat strains differ in sensitivity to the disruptive effects of dopamine agonists on sensorimotor gating, measured by prepulse inhibition (PPI) of startle. For example, Sprague Dawley (SD) rats are more sensitive to PPI-disruptive effects of apomorphine (APO) compared to Long Evans (LE) rats; F1 (SDxLE) and N2 generations exhibit intermediate phenotypes. We reported that APO increased S2/S1 ratios and reduced S1 amplitudes of the N40 event-related potential (ERP) in SD rats, suggesting that it reduced sensory gating and/or sensory registration. Here, we investigated whether SD and LE rats differ in sensitivity to APO effects on N40 gating or amplitude. METHODS PPI and N40 gating were assessed contemporaneously in male SD and LE rats after APO, in a 4-day within-subject design. RESULTS Compared to SD rats, LE rats were less sensitive to the PPI-disruptive effects of APO. APO increased S2/S1 ratios paralleled by a dose-dependent reduction in S1 amplitude; SD and LE rats did not differ significantly in this measure. No clear relationship was evident between APO effects on PPI and N40 gating, nor between APO effects on startle magnitude and S1 amplitude, across strains. CONCLUSION SD and LE rats differ in their sensitivity to the disruptive effects of dopamine receptor activation on sensorimotor gating (PPI) but not sensory gating (N40 suppression) or sensory registration (S1 amplitude). These data suggest differences in both the neural and genetic regulation of dopamine agonist effects on these measures.
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Affiliation(s)
- Michelle R Breier
- Department of Psychiatry, University of California, San Diego School of Medicine, La Jolla, CA 92093-0804, USA
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Freedman R, Goldowitz D. Studies on the hippocampal formation: From basic development to clinical applications: Studies on schizophrenia. Prog Neurobiol 2009; 90:263-75. [PMID: 19853005 DOI: 10.1016/j.pneurobio.2009.10.008] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2008] [Revised: 07/31/2009] [Accepted: 10/09/2009] [Indexed: 10/20/2022]
Abstract
The hippocampal formation plays a critical role in cognitive function. The developmental events that shape the hippocampal formation are continuing to be elucidated and their implications for brain function are emerging as well as applying those advances to interventions that have important possibilities for the treatment of brain dysfunction. The story told in this chapter is about the use of the in oculo transplant method to illuminate intrinsic and extrinsic features that underlie the development of the dentate gyrus and adjacent hippocampus and the role of one molecule in the hippocampus and schizophrenia. Schizophrenia, originally conceptualized as a dysfunction in dopaminergic neurotransmission, is now known to involve multiple neuronal systems. Dysfunction of hippocampal neurons is emerging as one of its signature pathological features. Basic insights into the development and function of hippocampal interneurons form the basis of a new treatment initiative for this illness. Evidence for the role of the alpha 7-nicotinic acetylcholine receptor in the development and function of these neurons in rodents has led to human trials of nicotinic agonists for cognitive dysfunction in schizophrenia and the possibility of improving hippocampal development in children at risk for schizophrenia by perinatal supplementation with choline, which can act as an alpha 7-nicotinic acetylcholine receptor agonist.
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Affiliation(s)
- Robert Freedman
- Dept Psychiatry, University of Colorado at Denver and Health Sciences Center, 13001 E. 17th Pl., Campus Box F546, Aurora, CO 800045, USA
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Rudnick ND, Koehler C, Picciotto MR, Siegel SJ. Role of beta2-containing nicotinic acetylcholine receptors in auditory event-related potentials. Psychopharmacology (Berl) 2009; 202:745-51. [PMID: 18931833 DOI: 10.1007/s00213-008-1358-6] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/30/2008] [Accepted: 09/26/2008] [Indexed: 01/26/2023]
Abstract
RATIONALE Nicotine improves sensory processing in schizophrenic individuals, as measured by changes in auditory event-related potentials (ERPs). Nicotine administration also alters ERPs in mice by increasing the amplitude and gating of the P20 ERP component while decreasing the amplitude of the N40 ERP component. Less is known about the role of specific nicotinic acetylcholine receptor (nAChR) subtypes. OBJECTIVES In this study, we examined whether nAChRs containing the beta2 subunit contribute to nicotine's effects on auditory ERPs. MATERIALS AND METHODS We tested the effect of nicotine in wild-type mice and mice lacking the beta2 nAChR subunit. Mice underwent stereotaxic implantation of stainless steel electrodes located in the CA3 region of the hippocampus, and 50 paired click stimuli were delivered during each drug condition. RESULTS There was no significant difference in P20 or N40 amplitude or gating between genotypes during the control condition, suggesting that beta2-containing receptors are not essential for the baseline auditory ERP response. Nicotine increased P20 amplitude and enhanced gating in wild-type and beta2 knockout mice, but only decreased N40 amplitude in wild-type mice. There was no effect of nicotine on N40 gating in either genotype. CONCLUSIONS beta2-containing receptors are necessary for nicotine's effects on the N40 component of the mouse auditory ERP. These results suggest that beta2-containing nAChRs modulate sensory processing and may serve as a therapeutic target in schizophrenic individuals.
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Affiliation(s)
- Noam D Rudnick
- Stanley Center for Experimental Therapeutics, Department of Psychiatry, University of Pennsylvania, Philadelphia, PA 19312, USA
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Turetsky BI, Greenwood TA, Olincy A, Radant AD, Braff DL, Cadenhead KS, Dobie DJ, Freedman R, Green MF, Gur RE, Gur RC, Light GA, Mintz J, Nuechterlein KH, Schork NJ, Seidman LJ, Siever LJ, Silverman JM, Stone WS, Swerdlow NR, Tsuang DW, Tsuang MT, Calkins ME. Abnormal auditory N100 amplitude: a heritable endophenotype in first-degree relatives of schizophrenia probands. Biol Psychiatry 2008; 64:1051-9. [PMID: 18701089 PMCID: PMC2653714 DOI: 10.1016/j.biopsych.2008.06.018] [Citation(s) in RCA: 102] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/18/2008] [Revised: 06/05/2008] [Accepted: 06/30/2008] [Indexed: 01/31/2023]
Abstract
BACKGROUND N100 evoked potential amplitude and gating abnormalities have been widely observed in schizophrenia patients. However, previous studies have been inconclusive as to whether similar deficits are present in unaffected family members. The Consortium on the Genetics of Schizophrenia (COGS) is a multisite National Institute of Mental Health (NIMH) initiative examining neurocognitive and neurophysiological measures as endophenotypes for genetic studies of schizophrenia. We report initial results from the COGS dataset of auditory N100 amplitude and gating as candidate endophenotypes. METHODS Evoked potential data were acquired from 142 schizophrenia probands, 373 unaffected first-degree relatives, and 221 community comparison subjects (CCS), using an auditory paired-click stimulation paradigm. Amplitude of the N100 response to each click and the click 2/click 1 ratio were dependent variables. Heritability was estimated based on kinships using Solar v.2.1.2. Group differences were examined after subjects were categorized as either "broad" or "narrow," based on the presence (broad) or absence (narrow) of nonpsychotic psychiatric comorbidity. RESULTS Heritability estimates were .40 and .29 for click1 and click2 amplitudes and .22 for the ratio. Broad and narrow patients both had impaired click 1 amplitudes. Broad relatives, but not narrow relatives, exhibited similar impairments. There were no group differences for either click 2 amplitude or the gating ratio. CONCLUSIONS N100 amplitude is a heritable measure that is abnormal in patients and a subset of relatives for whom psychiatric comorbidity may be a genetically associated phenotype. Auditory N100 gating, although heritable, is less viable as a schizophrenia endophenotype.
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Affiliation(s)
- Bruce I. Turetsky
- Department of Psychiatry, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Tiffany A. Greenwood
- Department of Psychiatry, University of California San Diego, San Diego, California, USA
| | - Ann Olincy
- Department of Psychiatry, University of Colorado Health Sciences Center, Denver, Colorado, USA
| | - Allen D. Radant
- Department of Psychiatry and Behavioral Sciences, University of Washington, Seattle, Washington, and VA Puget Sound Health Care System, Seattle, Washington, USA
| | - David L. Braff
- Department of Psychiatry, University of California San Diego, San Diego, California, USA
| | - Kristin S. Cadenhead
- Department of Psychiatry, University of California San Diego, San Diego, California, USA
| | - Dorcas J. Dobie
- Department of Psychiatry and Behavioral Sciences, University of Washington, Seattle, Washington, and VA Puget Sound Health Care System, Seattle, Washington, USA
| | - Robert Freedman
- Department of Psychiatry, University of Colorado Health Sciences Center, Denver, Colorado, USA
| | - Michael F. Green
- Department of Psychiatry and Biobehavioral Sciences, Geffen School of Medicine at University of California Los Angeles, Los Angeles, California, USA.,VA Greater Los Angeles Healthcare System
| | - Raquel E. Gur
- Department of Psychiatry, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Ruben C. Gur
- Department of Psychiatry, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Gregory A. Light
- Department of Psychiatry, University of California San Diego, San Diego, California, USA
| | - James Mintz
- Department of Psychiatry and Biobehavioral Sciences, Geffen School of Medicine at University of California Los Angeles, Los Angeles, California, USA
| | - Keith H. Nuechterlein
- Department of Psychiatry and Biobehavioral Sciences, Geffen School of Medicine at University of California Los Angeles, Los Angeles, California, USA
| | - Nicholas J. Schork
- Scripps Genomic Medicine, La Jolla, CA, USA,Department of Molecular and Experimental Medicine, The Scripps Research Institute, La Jolla, CA, USA
| | - Larry J. Seidman
- Massachusetts Mental Health Center Public Psychiatry Division of the Beth Israel Deaconess Medical Center, Harvard Medical School Department of Psychiatry, Boston, Massachusetts, and Harvard Institute of Psychiatric Epidemiology and Genetics, Boston, Massachusetts, USA
| | - Larry J. Siever
- Department of Psychiatry, The Mount Sinai School of Medicine, New York, New York, USA.,James J. Peters VA Medical Center and VISN3 MIRECC
| | - Jeremy M. Silverman
- Department of Psychiatry, The Mount Sinai School of Medicine, New York, New York, USA
| | - William S. Stone
- Massachusetts Mental Health Center Public Psychiatry Division of the Beth Israel Deaconess Medical Center, Harvard Medical School Department of Psychiatry, Boston, Massachusetts, and Harvard Institute of Psychiatric Epidemiology and Genetics, Boston, Massachusetts, USA
| | - Neal R. Swerdlow
- Department of Psychiatry, University of California San Diego, San Diego, California, USA
| | - Debby W. Tsuang
- Department of Psychiatry and Behavioral Sciences, University of Washington, Seattle, Washington, and VA Puget Sound Health Care System, Seattle, Washington, USA
| | - Ming T. Tsuang
- Department of Psychiatry, University of California San Diego, San Diego, California, USA.,Massachusetts Mental Health Center Public Psychiatry Division of the Beth Israel Deaconess Medical Center, Harvard Medical School Department of Psychiatry, Boston, Massachusetts, and Harvard Institute of Psychiatric Epidemiology and Genetics, Boston, Massachusetts, USA
| | - Monica E. Calkins
- Department of Psychiatry, University of Pennsylvania, Philadelphia, Pennsylvania, USA
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Ehrlichman RS, Gandal MJ, Maxwell CR, Lazarewicz MT, Finkel LH, Contreras D, Turetsky BI, Siegel SJ. N-methyl-d-aspartic acid receptor antagonist-induced frequency oscillations in mice recreate pattern of electrophysiological deficits in schizophrenia. Neuroscience 2008; 158:705-12. [PMID: 19015010 DOI: 10.1016/j.neuroscience.2008.10.031] [Citation(s) in RCA: 140] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2008] [Revised: 10/16/2008] [Accepted: 11/14/2008] [Indexed: 12/20/2022]
Abstract
INTRODUCTION Electrophysiological responses to auditory stimuli have provided a useful means of elucidating mechanisms and evaluating treatments in psychiatric disorders. Deficits in gating during paired-click tasks and lack of mismatch negativity following deviant stimuli have been well characterized in patients with schizophrenia. Recently, analyses of basal, induced, and evoked frequency oscillations have gained support as additional measures of cognitive processing in patients and animal models. The purpose of this study is to examine frequency oscillations in mice across the theta (4-7.5 Hz) and gamma (31-61 Hz) bands in the context of N-methyl-d-aspartic acid receptor (NMDAR) hypofunction and dopaminergic hyperactivity, both of which are thought to serve as pharmacological models of schizophrenia. EXPERIMENTAL PROCEDURES Electroencephalograms (EEG) were recorded from mice in five treatment groups that consisted of haloperidol, risperidone, amphetamine, ketamine, or ketamine plus haloperidol during an auditory task. Basal, induced and evoked powers in both frequencies were calculated. RESULTS Ketamine increased basal power in the gamma band and decreased the evoked power in the theta band. The increase in basal gamma was not blocked by treatment with a conventional antipsychotic. No other treatment group was able to fully reproduce this pattern in the mice. CONCLUSIONS Ketamine-induced alterations in EEG power spectra are consistent with abnormalities in the theta and gamma frequency ranges reported in patients with schizophrenia. Our findings support the hypothesis that NMDAR hypofunction contributes to the deficits in schizophrenia and that the dopaminergic pathways alone may not account for these changes.
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Affiliation(s)
- R S Ehrlichman
- Stanley Center for Experimental Therapeutics in Psychiatry, Department of Psychiatry, University of Pennsylvania, Philadelphia, PA 19104, USA
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Halene TB, Siegel SJ. Antipsychotic-like properties of phosphodiesterase 4 inhibitors: evaluation of 4-(3-butoxy-4-methoxybenzyl)-2-imidazolidinone (RO-20-1724) with auditory event-related potentials and prepulse inhibition of startle. J Pharmacol Exp Ther 2008; 326:230-9. [PMID: 18420599 DOI: 10.1124/jpet.108.138586] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Antipsychotic medications function through antagonism of D2 dopamine receptors. Blockade of D2 receptors causes an increase in intracellular cAMP, a ubiquitous second messenger. Inhibition of phosphodiesterase (PDE) activity, a family of enzymes that degrade cyclic nucleotides, causes the same effect. The conceptual linkage between dopamine D2 receptors and PDE activity via cAMP suggests a possible therapeutic potential for PDE inhibitors in schizophrenia. The limited number of studies in support of this hypothesis used rolipram, a specific inhibitor of the PDE4 family. In this study, we investigated the impact of 4-(3-butoxy-4-methoxybenzyl)-2-imidazolidinone (RO-20-1724), another PDE4-specific inhibitor, on auditory event-related potentials (ERPs), prepulse inhibition (PPI) of the startle reflex, and locomotor activity in mice. The ability to reverse amphetamine-induced alterations in ERPs and PPI was used as a model for psychosis. ERPs after RO-20-1724 revealed increased amplitude for the P20 and N40 ERP components. RO-20-1724 reversed the disruptive effect of amphetamines on ERPs and restored gating at a dose that did not impair locomotor activity. However, RO-20-1724 failed to reverse a amphetamine-induced decrease of PPI. Inconsistent results between these two psychosis models suggest that pure sensory processing, as measured with auditory ERPs, may be more sensitive to the effects of intracellular cAMP than sensorimotor effects as assessed with PPI. It remains unclear whether antipsychotic-like properties are a common feature of PDE4 inhibition, or if they are restricted to the pharmacological profile of rolipram. Future studies should examine how PDE4 subtype specificity might contribute to differences between rolipram and RO-20-1724 in sensorimotor gating.
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Affiliation(s)
- T B Halene
- International Research Training Group 1328 Schizophrenia and Autism, Department of Psychiatry and Psychotherapy, RWTH Aachen University, Aachen, Germany
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PDE inhibitors in psychiatry--future options for dementia, depression and schizophrenia? Drug Discov Today 2007; 12:870-8. [PMID: 17933689 DOI: 10.1016/j.drudis.2007.07.023] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2007] [Revised: 07/21/2007] [Accepted: 07/23/2007] [Indexed: 02/07/2023]
Abstract
Phosphodiesterases are key enzymes in cellular signalling pathways. They degrade cyclic nucleotides and their inhibition via specific inhibitors offers unique 'receptor-independent' opportunities to modify cellular function. An increasing number of in vitro and animal model studies point to innovative treatment options in neurology and psychiatry. This review critiques a selection of recent studies and developments with a focus on dementia/neuroprotection, depression and schizophrenia. Despite increased interest among the clinical neurosciences, there are still no approved PDE inhibitors for clinical use in neurology or psychiatry. Adverse effects are a major impediment for clinical approval. It is therefore necessary to search for more specific inhibitors at the level of different PDE sub-families and isoforms.
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