1
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Kellogg CM, Pham K, Ko S, Cox JE, Machalinski AH, Stout MB, Sharpe AL, Beckstead MJ, Chucair-Elliott AJ, Ocañas SR, Freeman WM. Specificity and efficiency of tamoxifen-mediated Cre induction is equivalent regardless of age. iScience 2023; 26:108413. [PMID: 38058312 PMCID: PMC10696116 DOI: 10.1016/j.isci.2023.108413] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2023] [Revised: 10/15/2023] [Accepted: 11/02/2023] [Indexed: 12/08/2023] Open
Abstract
Temporally controlling Cre recombination through tamoxifen (Tam) induction has many advantages for biomedical research. Most studies report early post-natal/juvenile (<2 m.o.) Tam induction, but age-related neurodegeneration and aging studies can require Cre induction in older mice (>12 m.o.). While anecdotally reported as problematic, there are no published comparisons of Tam-mediated Cre induction at early and late ages. Here, microglial-specific Cx3cr1creERT2 mice were crossed to a floxed NuTRAP reporter to compare Cre induction at early (3-6 m.o.) and late (20 m.o.) ages. Specificity and efficiency of microglial labeling at 21-22 m.o. were identical in mice induced with Tam at early and late ages. Age-related microglial translatomic changes were also similar regardless of Tam induction age. Each Cre and flox mouse line should be independently validated, however, these findings demonstrate that Tam-mediated Cre induction can be performed even into older mouse ages and should be generalizable to other inducible Cre models.
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Affiliation(s)
- Collyn M. Kellogg
- Genes & Human Disease Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA
- Department of Biochemistry & Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Kevin Pham
- Genes & Human Disease Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA
| | - Sunghwan Ko
- Genes & Human Disease Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA
- Neuroscience Graduate Program, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Jillian E.J. Cox
- Genes & Human Disease Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA
- Neuroscience Graduate Program, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Adeline H. Machalinski
- Genes & Human Disease Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA
| | - Michael B. Stout
- Aging & Metabolism Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA
| | - Amanda L. Sharpe
- Department of Pharmaceutical Sciences, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
- Neuroscience Graduate Program, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Michael J. Beckstead
- Aging & Metabolism Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA
- Oklahoma City Veterans Affairs Medical Center, Oklahoma City, OK, USA
| | - Ana J. Chucair-Elliott
- Genes & Human Disease Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA
| | - Sarah R. Ocañas
- Genes & Human Disease Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA
- Neuroscience Graduate Program, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
- Department of Physiology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Willard M. Freeman
- Genes & Human Disease Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA
- Department of Biochemistry & Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
- Oklahoma City Veterans Affairs Medical Center, Oklahoma City, OK, USA
- Neuroscience Graduate Program, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
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2
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Blankenship HE, Carter KA, Cassidy NT, Markiewicz AN, Thellmann MI, Sharpe AL, Freeman WM, Beckstead MJ. VTA dopamine neurons are hyperexcitable in 3xTg-AD mice due to casein kinase 2-dependent SK channel dysfunction. bioRxiv 2023:2023.11.16.567486. [PMID: 38014232 PMCID: PMC10680865 DOI: 10.1101/2023.11.16.567486] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2023]
Abstract
Alzheimer's disease (AD) patients exhibit neuropsychiatric symptoms that extend beyond classical cognitive deficits, suggesting involvement of subcortical areas. Here, we investigated the role of midbrain dopamine (DA) neurons in AD using the amyloid + tau-driven 3xTg-AD mouse model. We found deficits in reward-based operant learning in AD mice, suggesting possible VTA DA neuron dysregulation. Physiological assessment revealed hyperexcitability and disrupted firing in DA neurons caused by reduced activity of small-conductance calcium-activated potassium (SK) channels. RNA sequencing from contents of single patch-clamped DA neurons (Patch-seq) identified up-regulation of the SK channel modulator casein kinase 2 (CK2). Pharmacological inhibition of CK2 restored SK channel activity and normal firing patterns in 3xTg-AD mice. These findings shed light on a complex interplay between neuropsychiatric symptoms and subcortical circuits in AD, paving the way for novel treatment strategies.
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3
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Kellogg CM, Pham K, Machalinski AH, Porter HL, Blankenship HE, Tooley KB, Stout MB, Rice HC, Sharpe AL, Beckstead MJ, Chucair-Elliott AJ, Ocañas SR, Freeman WM. Correction to: Microglial MHC‑I induction with aging and Alzheimer's is conserved in mouse models and humans. GeroScience 2023; 45:3101-3102. [PMID: 37556087 PMCID: PMC10643469 DOI: 10.1007/s11357-023-00881-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/10/2023] Open
Affiliation(s)
- Collyn M Kellogg
- Genes and Human Disease Program, Oklahoma Medical Research Foundation, 825 NE 13Th Street, Oklahoma City, OK, USA
- Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Kevin Pham
- Genes and Human Disease Program, Oklahoma Medical Research Foundation, 825 NE 13Th Street, Oklahoma City, OK, USA
| | - Adeline H Machalinski
- Genes and Human Disease Program, Oklahoma Medical Research Foundation, 825 NE 13Th Street, Oklahoma City, OK, USA
| | - Hunter L Porter
- Genes and Human Disease Program, Oklahoma Medical Research Foundation, 825 NE 13Th Street, Oklahoma City, OK, USA
| | - Harris E Blankenship
- Department of Physiology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Kyla B Tooley
- Genes and Human Disease Program, Oklahoma Medical Research Foundation, 825 NE 13Th Street, Oklahoma City, OK, USA
- Department of Physiology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Michael B Stout
- Aging and Metabolism Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA
| | - Heather C Rice
- Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Amanda L Sharpe
- Department of Pharmaceutical Sciences, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Michael J Beckstead
- Genes and Human Disease Program, Oklahoma Medical Research Foundation, 825 NE 13Th Street, Oklahoma City, OK, USA
- Aging and Metabolism Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA
- Oklahoma City Veterans Affairs Medical Center, Oklahoma City, OK, USA
| | - Ana J Chucair-Elliott
- Genes and Human Disease Program, Oklahoma Medical Research Foundation, 825 NE 13Th Street, Oklahoma City, OK, USA
| | - Sarah R Ocañas
- Genes and Human Disease Program, Oklahoma Medical Research Foundation, 825 NE 13Th Street, Oklahoma City, OK, USA
- Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Willard M Freeman
- Genes and Human Disease Program, Oklahoma Medical Research Foundation, 825 NE 13Th Street, Oklahoma City, OK, USA.
- Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA.
- Oklahoma City Veterans Affairs Medical Center, Oklahoma City, OK, USA.
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Kellogg CM, Pham K, Machalinski AH, Porter HL, Blankenship HE, Tooley KB, Stout MB, Rice HC, Sharpe AL, Beckstead MJ, Chucair-Elliott AJ, Ocañas SR, Freeman WM. Microglial MHC-I induction with aging and Alzheimer's is conserved in mouse models and humans. GeroScience 2023; 45:3019-3043. [PMID: 37393197 PMCID: PMC10643718 DOI: 10.1007/s11357-023-00859-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2023] [Accepted: 06/21/2023] [Indexed: 07/03/2023] Open
Abstract
Major histocompatibility complex I (MHC-I) CNS cellular localization and function is still being determined after previously being thought to be absent from the brain. MHC-I expression has been reported to increase with brain aging in mouse, rat, and human whole tissue analyses, but the cellular localization was undetermined. Neuronal MHC-I is proposed to regulate developmental synapse elimination and tau pathology in Alzheimer's disease (AD). Here, we report that across newly generated and publicly available ribosomal profiling, cell sorting, and single-cell data, microglia are the primary source of classical and non-classical MHC-I in mice and humans. Translating ribosome affinity purification-qPCR analysis of 3-6- and 18-22-month-old (m.o.) mice revealed significant age-related microglial induction of MHC-I pathway genes B2m, H2-D1, H2-K1, H2-M3, H2-Q6, and Tap1 but not in astrocytes and neurons. Across a timecourse (12-23 m.o.), microglial MHC-I gradually increased until 21 m.o. and then accelerated. MHC-I protein was enriched in microglia and increased with aging. Microglial expression, and absence in astrocytes and neurons, of MHC-I-binding leukocyte immunoglobulin-like (Lilrs) and paired immunoglobin-like type 2 (Pilrs) receptor families could enable cell -autonomous MHC-I signaling and increased with aging in mice and humans. Increased microglial MHC-I, Lilrs, and Pilrs were observed in multiple AD mouse models and human AD data across methods and studies. MHC-I expression correlated with p16INK4A, suggesting an association with cellular senescence. Conserved induction of MHC-I, Lilrs, and Pilrs with aging and AD opens the possibility of cell-autonomous MHC-I signaling to regulate microglial reactivation with aging and neurodegeneration.
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Affiliation(s)
- Collyn M Kellogg
- Genes and Human Disease Program, Oklahoma Medical Research Foundation, 825 NE 13Th Street, Oklahoma City, OK, USA
- Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Kevin Pham
- Genes and Human Disease Program, Oklahoma Medical Research Foundation, 825 NE 13Th Street, Oklahoma City, OK, USA
| | - Adeline H Machalinski
- Genes and Human Disease Program, Oklahoma Medical Research Foundation, 825 NE 13Th Street, Oklahoma City, OK, USA
| | - Hunter L Porter
- Genes and Human Disease Program, Oklahoma Medical Research Foundation, 825 NE 13Th Street, Oklahoma City, OK, USA
| | - Harris E Blankenship
- Department of Physiology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Kyla B Tooley
- Genes and Human Disease Program, Oklahoma Medical Research Foundation, 825 NE 13Th Street, Oklahoma City, OK, USA
- Department of Physiology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Michael B Stout
- Aging and Metabolism Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA
| | - Heather C Rice
- Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Amanda L Sharpe
- Department of Pharmaceutical Sciences, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Michael J Beckstead
- Aging and Metabolism Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA
- Oklahoma City Veterans Affairs Medical Center, Oklahoma City, OK, USA
| | - Ana J Chucair-Elliott
- Genes and Human Disease Program, Oklahoma Medical Research Foundation, 825 NE 13Th Street, Oklahoma City, OK, USA
| | - Sarah R Ocañas
- Genes and Human Disease Program, Oklahoma Medical Research Foundation, 825 NE 13Th Street, Oklahoma City, OK, USA
- Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Willard M Freeman
- Genes and Human Disease Program, Oklahoma Medical Research Foundation, 825 NE 13Th Street, Oklahoma City, OK, USA.
- Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA.
- Oklahoma City Veterans Affairs Medical Center, Oklahoma City, OK, USA.
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5
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Kellogg CM, Pham K, Ko S, Cox JEJ, Machalinski AH, Stout MB, Sharpe AL, Beckstead MJ, Chucair-Elliott AJ, Ocañas SR, Freeman WM. Consistent specificity and efficiency of tamoxifen-mediated cre induction across ages. bioRxiv 2023:2023.09.19.558482. [PMID: 37781585 PMCID: PMC10541132 DOI: 10.1101/2023.09.19.558482] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/03/2023]
Abstract
Temporally controlling cre recombination through tamoxifen (Tam) induction has many advantages for biomedical research. Most studies report Tam induction at early post-natal/juvenile (<2 m.o.) mouse ages, but age-related neurodegeneration and aging studies can require cre induction in older mice (>12 m.o.). While anecdotally reported as problematic, there are no published comparisons of Tam mediated cre induction at early and late ages. Here, microglial-specific Cx3cr1 creERT 2 mice were crossed to a floxed NuTRAP reporter to compare cre induction at early (3-6 m.o.) and late (20 m.o.) ages. Specificity and efficiency of microglial labeling at 21-22 m.o. were identical in mice induced with Tam at 3-6 m.o. or 20 m.o. of age. Age-related microglial translatomic changes were also similar regardless of Tam induction age. Each cre and flox mouse line should be validated independently, however, these findings demonstrate that Tam-mediated cre induction can be performed even into older mouse ages.
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6
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Kellogg CM, Pham K, Machalinski AH, Porter HL, Blankenship HE, Tooley K, Stout MB, Rice HC, Sharpe AL, Beckstead MJ, Chucair-Elliott AJ, Ocañas SR, Freeman WM. Microglial MHC-I induction with aging and Alzheimer's is conserved in mouse models and humans. bioRxiv 2023:2023.03.07.531435. [PMID: 36945372 PMCID: PMC10028873 DOI: 10.1101/2023.03.07.531435] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/12/2023]
Abstract
Major Histocompatibility Complex I (MHC-I) CNS cellular localization and function is still being determined after previously being thought to be absent from the brain. MHC-I expression has been reported to increase with brain aging in mouse, rat, and human whole tissue analyses but the cellular localization was undetermined. Neuronal MHC-I is proposed to regulate developmental synapse elimination and tau pathology in Alzheimer's disease (AD). Here we report that across newly generated and publicly available ribosomal profiling, cell sorting, and single-cell data, microglia are the primary source of classical and non-classical MHC-I in mice and humans. Translating Ribosome Affinity Purification-qPCR analysis of 3-6 and 18-22 month old (m.o.) mice revealed significant age-related microglial induction of MHC-I pathway genes B2m , H2-D1 , H2-K1 , H2-M3 , H2-Q6 , and Tap1 but not in astrocytes and neurons. Across a timecourse (12-23 m.o.), microglial MHC-I gradually increased until 21 m.o. and then accelerated. MHC-I protein was enriched in microglia and increased with aging. Microglial expression, and absence in astrocytes and neurons, of MHC-I binding Leukocyte Immunoglobulin-like (Lilrs) and Paired immunoglobin-like type 2 (Pilrs) receptor families could enable cell-autonomous MHC-I signaling and increased with aging in mice and humans. Increased microglial MHC-I, Lilrs, and Pilrs were observed in multiple AD mouse models and human AD data across methods and studies. MHC-I expression correlated with p16INK4A , suggesting an association with cellular senescence. Conserved induction of MHC-I, Lilrs, and Pilrs with aging and AD opens the possibility of cell-autonomous MHC-I signaling to regulate microglial reactivation with aging and neurodegeneration.
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Affiliation(s)
- Collyn M. Kellogg
- Genes & Human Disease Program, Oklahoma Medical Research Foundation, Oklahoma City, OK USA
- Department of Biochemistry & Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK USA
| | - Kevin Pham
- Genes & Human Disease Program, Oklahoma Medical Research Foundation, Oklahoma City, OK USA
| | - Adeline H. Machalinski
- Genes & Human Disease Program, Oklahoma Medical Research Foundation, Oklahoma City, OK USA
| | - Hunter L. Porter
- Genes & Human Disease Program, Oklahoma Medical Research Foundation, Oklahoma City, OK USA
| | - Harris E. Blankenship
- Department of Physiology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Kyla Tooley
- Genes & Human Disease Program, Oklahoma Medical Research Foundation, Oklahoma City, OK USA
- Department of Physiology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Michael B. Stout
- Aging & Metabolism Program, Oklahoma Medical Research Foundation, Oklahoma City, OK USA
| | - Heather C. Rice
- Department of Biochemistry & Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK USA
| | - Amanda L. Sharpe
- Department of Pharmaceutical Sciences, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Michael J. Beckstead
- Aging & Metabolism Program, Oklahoma Medical Research Foundation, Oklahoma City, OK USA
- Oklahoma City Veterans Affairs Medical Center, Oklahoma City, OK USA
| | - Ana J. Chucair-Elliott
- Genes & Human Disease Program, Oklahoma Medical Research Foundation, Oklahoma City, OK USA
| | - Sarah R. Ocañas
- Genes & Human Disease Program, Oklahoma Medical Research Foundation, Oklahoma City, OK USA
- Department of Biochemistry & Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK USA
| | - Willard M. Freeman
- Genes & Human Disease Program, Oklahoma Medical Research Foundation, Oklahoma City, OK USA
- Department of Biochemistry & Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK USA
- Oklahoma City Veterans Affairs Medical Center, Oklahoma City, OK USA
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7
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Dominguez-Lopez S, Ahn B, Sataranatarajan K, Ranjit R, Premkumar P, Van Remmen H, Beckstead MJ. Long-term methamphetamine self-administration increases mesolimbic mitochondrial oxygen consumption and decreases striatal glutathione. Neuropharmacology 2023; 227:109436. [PMID: 36693561 PMCID: PMC10080784 DOI: 10.1016/j.neuropharm.2023.109436] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Revised: 12/26/2022] [Accepted: 01/20/2023] [Indexed: 01/22/2023]
Abstract
Neurotoxic regimens of methamphetamine (METH) are known to increase reactive oxygen species (ROS), affect redox homeostasis, and lead to damage in dopamine neurons. Functional changes induced by long-term METH self-administration on mitochondrial respiratory metabolism and redox homeostasis are less known. To fill this gap, we implanted a jugular catheter into adult male mice and trained them to nose poke for METH infusions. After several weeks of METH exposure, we collected samples of the ventral striatum (vST) and the ventral midbrain (vMB). We used HPLC to determine the levels of the ROS scavenger glutathione in its reduced (GSH) and oxidized forms. Then, we used high-resolution respirometry to determine the oxygen consumption rate (OCR) of mitochondrial complexes. Finally, using in vivo electrophysiology, we assessed changes in dopamine neuron firing activity in the VTA. METH self-administration produced a decrease of the GSH pool in vST, correlating with lifetime METH intake. We observed increased mitochondrial respiration across the two mesolimbic regions. METH self-administration decreases firing rate and burst activity but increases the number of spontaneously active dopamine neurons per track. We conclude that METH self-administration progressively decreased the antioxidant pool in sites of higher dopamine release and produced an increase in mitochondrial metabolism in the mesolimbic areas, probably derived from the increased number of dopamine neurons actively firing. However, dopamine neuron firing activity is decreased by METH self-administration, reflecting a new basal level of dopamine neurotransmission.
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Affiliation(s)
- Sergio Dominguez-Lopez
- Department of Anatomy and Neurobiology, University of Maryland, School of Medicine, Baltimore, MD, 21201, USA; Aging and Metabolism Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, 73104, USA.
| | - Bumsoo Ahn
- Aging and Metabolism Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, 73104, USA
| | | | - Rojina Ranjit
- Aging and Metabolism Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, 73104, USA
| | - Pavithra Premkumar
- Aging and Metabolism Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, 73104, USA
| | - Holly Van Remmen
- Aging and Metabolism Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, 73104, USA; Oklahoma City Veterans Affairs Medical Center, Oklahoma City, OK, 73104, USA
| | - Michael J Beckstead
- Aging and Metabolism Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, 73104, USA; Oklahoma City Veterans Affairs Medical Center, Oklahoma City, OK, 73104, USA
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8
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Higgs MH, Jones JA, Wilson CJ, Beckstead MJ. SK and Kv4 channels limit spike timing perturbations in pacemaking dopamine neurons. eNeuro 2023; 10:ENEURO.0445-22.2023. [PMID: 36973012 PMCID: PMC10088984 DOI: 10.1523/eneuro.0445-22.2023] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Revised: 01/18/2023] [Accepted: 02/04/2023] [Indexed: 03/29/2023] Open
Abstract
Midbrain dopamine (DA) neurons are among the best characterized pacemaker neurons, having intrinsic, rhythmic firing activity even in the absence of synaptic input. However, the mechanisms of DA neuron pacemaking have not been systematically related to how these cells respond to synaptic input. The input-output properties of pacemaking neurons can be characterized by the phase resetting curve (PRC), which describes the sensitivity of inter-spike interval (ISI) length to inputs arriving at different phases of the firing cycle. Here we determined PRCs of putative DA neurons in the substantia nigra pars compacta (SNc) in brain slices from male and female mice using gramicidin-perforated current-clamp recordings with electrical noise stimuli applied through the patch pipette. On average, and compared to nearby putative GABA neurons, DA neurons showed a low, nearly constant level of sensitivity across most of the ISI, but individual cells had PRCs showing relatively greater sensitivity at early or late phases. Pharmacological experiments showed that DA neuron PRCs are shaped by small-conductance calcium-activated potassium (SK) and Kv4 channels, which limit input-sensitivity across early and late phases of the ISI. Our results establish the PRC as a tractable experimental measurement of individual DA neuron input-output relationships and identify two of the major ionic conductances that limit perturbations to rhythmic firing. These findings have applications in modeling and for identifying biophysical changes in response to disease or environmental manipulations.SIGNIFICANCE STATEMENTIn substantia nigra pars compacta dopamine neurons, pacemaking mechanisms determine the response to an instantaneous synaptic input according to the phase resetting curve (PRC). Here we measured PRCs of dopamine neurons and determined how they are shaped by small-conductance calcium-activated potassium (SK) and Kv4 channels, which regulate pacemaking rate and regularity. We found that both types of channel limit sensitivity to perturbations in firing. Thus, the currents responsible for slow pacemaking also control spike time responses to synaptic input.
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Affiliation(s)
- Matthew H Higgs
- Aging & Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK
| | - James A Jones
- Department of Neuroscience, Developmental, and Regenerative Biology, University of Texas at San Antonio, San Antonio, TX
| | - Charles J Wilson
- Department of Neuroscience, Developmental, and Regenerative Biology, University of Texas at San Antonio, San Antonio, TX
| | - Michael J Beckstead
- Aging & Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK
- Oklahoma City VA Medical Center, Oklahoma City, OK
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9
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Bhaskaran S, Kumar G, Thadathil N, Piekarz KM, Mohammed S, Lopez SD, Qaisar R, Walton D, Brown JL, Murphy A, Smith N, Saunders D, Beckstead MJ, Plafker S, Lewis TL, Towner R, Deepa SS, Richardson A, Axtell RC, Van Remmen H. Neuronal deletion of MnSOD in mice leads to demyelination, inflammation and progressive paralysis that mimics phenotypes associated with progressive multiple sclerosis. Redox Biol 2023; 59:102550. [PMID: 36470129 PMCID: PMC9720104 DOI: 10.1016/j.redox.2022.102550] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2022] [Revised: 11/17/2022] [Accepted: 11/21/2022] [Indexed: 11/27/2022] Open
Abstract
Neuronal oxidative stress has been implicated in aging and neurodegenerative disease. Here we investigated the impact of elevated oxidative stress induced in mouse spinal cord by deletion of Mn-Superoxide dismutase (MnSOD) using a neuron specific Cre recombinase in Sod2 floxed mice (i-mn-Sod2 KO). Sod2 deletion in spinal cord neurons was associated with mitochondrial alterations and peroxide generation. Phenotypically, i-mn-Sod2 KO mice experienced hindlimb paralysis and clasping behavior associated with extensive demyelination and reduced nerve conduction velocity, axonal degeneration, enhanced blood brain barrier permeability, elevated inflammatory cytokines, microglia activation, infiltration of neutrophils and necroptosis in spinal cord. In contrast, spinal cord motor neuron number, innervation of neuromuscular junctions, muscle mass, and contractile function were not altered. Overall, our findings show that loss of MnSOD in spinal cord promotes a phenotype of demyelination, inflammation and progressive paralysis that mimics phenotypes associated with progressive multiple sclerosis.
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Affiliation(s)
- Shylesh Bhaskaran
- Aging & Metabolism Research Program, Oklahoma Medical Research Foundation, OK, USA
| | - Gaurav Kumar
- Arthritis & Clinical Immunology, Oklahoma Medical Research Foundation, OK, USA
| | - Nidheesh Thadathil
- Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, OK, USA
| | - Katarzyna M Piekarz
- Aging & Metabolism Research Program, Oklahoma Medical Research Foundation, OK, USA
| | - Sabira Mohammed
- Stephenson Cancer Center, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | | | - Rizwan Qaisar
- Aging & Metabolism Research Program, Oklahoma Medical Research Foundation, OK, USA
| | - Dorothy Walton
- Aging & Metabolism Research Program, Oklahoma Medical Research Foundation, OK, USA
| | - Jacob L Brown
- Aging & Metabolism Research Program, Oklahoma Medical Research Foundation, OK, USA; Oklahoma City VA Medical Center, Oklahoma City, OK, USA
| | - Ashley Murphy
- Aging & Metabolism Research Program, Oklahoma Medical Research Foundation, OK, USA
| | - Nataliya Smith
- Advanced Magnetic Resonance Center, Oklahoma Medical Research Foundation, OK, USA
| | - Debra Saunders
- Advanced Magnetic Resonance Center, Oklahoma Medical Research Foundation, OK, USA
| | - Michael J Beckstead
- Aging & Metabolism Research Program, Oklahoma Medical Research Foundation, OK, USA; Oklahoma City VA Medical Center, Oklahoma City, OK, USA
| | - Scott Plafker
- Aging & Metabolism Research Program, Oklahoma Medical Research Foundation, OK, USA
| | - Tommy L Lewis
- Aging & Metabolism Research Program, Oklahoma Medical Research Foundation, OK, USA
| | - Rheal Towner
- Advanced Magnetic Resonance Center, Oklahoma Medical Research Foundation, OK, USA
| | - Sathyaseelan S Deepa
- Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, OK, USA; Stephenson Cancer Center, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Arlan Richardson
- Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, OK, USA; Stephenson Cancer Center, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA; Oklahoma City VA Medical Center, Oklahoma City, OK, USA
| | - Robert C Axtell
- Arthritis & Clinical Immunology, Oklahoma Medical Research Foundation, OK, USA.
| | - Holly Van Remmen
- Aging & Metabolism Research Program, Oklahoma Medical Research Foundation, OK, USA; Oklahoma City VA Medical Center, Oklahoma City, OK, USA.
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10
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Troyano-Rodriguez E, Blankenship HE, Handa K, Branch SY, Beckstead MJ. Preservation of dendritic D2 receptor transmission in substantia nigra dopamine neurons with age. Sci Rep 2023; 13:1025. [PMID: 36658269 PMCID: PMC9852430 DOI: 10.1038/s41598-023-28174-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Accepted: 01/13/2023] [Indexed: 01/20/2023] Open
Abstract
Substantia nigra pars compacta (SNc) dopamine neurons are required for voluntary movement and reward learning, and advanced age is associated with motor and cognitive decline. In the midbrain, D2-type dopamine receptors located at dendrodendritic synapses between dopamine neurons control cell firing through G protein-activated potassium (GIRK) channels. We previously showed that aging disrupts dopamine neuron pacemaker firing in mice, but only in males. Here we show that the amplitude of D2-receptor inhibitory postsynaptic currents (D2-IPSCs) are moderately reduced in aged male mice. Local application of dopamine revealed a reduction in the amplitude of the D2-receptor currents in old males compared to young, pointing to a postsynaptic mechanism. Further experiments indicated that reduced D2 receptor signaling was not due to a general reduction in GIRK channel currents or degeneration of the dendritic arbor. Kinetic analysis showed no differences in D2-IPSC shape in old versus young mice or between sexes. Potentiation of D2-IPSCs by corticotropin releasing factor (CRF) was also not affected by age, indicating preservation of one mechanism of plasticity. These findings have implications for understanding dopamine transmission in aging, and reduced D2 receptor inhibition could contribute to increased susceptibility of males to SNc dopamine neuron degeneration in Parkinson's disease.
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Affiliation(s)
- Eva Troyano-Rodriguez
- Aging and Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA
| | - Harris E Blankenship
- Aging and Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA
| | - Kylie Handa
- Aging and Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA
| | - Sarah Y Branch
- Department of Cellular and Integrative Physiology, University of Texas Health, San Antonio, TX, USA
| | - Michael J Beckstead
- Aging and Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA.
- Oklahoma City VA Medical Center, Oklahoma City, OK, USA.
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11
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Perez-Bonilla P, Ramirez-Virella J, Menon P, Troyano-Rodriguez E, Arriaga SK, Makela A, Bugescu R, Beckstead MJ, Leinninger GM. Developmental or adult-onset deletion of neurotensin receptor-1 from dopamine neurons differentially reduces body weight. Front Neurosci 2022; 16:874316. [PMID: 36213756 PMCID: PMC9537700 DOI: 10.3389/fnins.2022.874316] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2022] [Accepted: 08/17/2022] [Indexed: 11/13/2022] Open
Abstract
Central neurotensin signaling via neurotensin receptor-1 (NtsR1) modulates various aspects of physiology, including suppressing feeding and promoting locomotor activity that can support weight loss. However, it remains unclear when and where NtsR1 expression contributes to control of body weight vs. other effects. We previously showed that activating ventral tegmental area (VTA) dopamine (DA) neurons that express NtsR1 promotes weight loss. We therefore hypothesized that deleting NtsR1 from DA neurons would promote weight gain by increasing food intake and decreasing physical activity. In contrast, developmental deletion of NtsR1 from DA neurons (by crossing DATCre mice with NtsR1flox/flox mice) had no impact on the feeding or body weight of mice fed a chow diet, though it augmented locomotor activity. Developmental deletion of NtsR1 from DA neurons protected mice from diet-induced obesity, but not via altering feeding, physical activity, or energy expenditure. Given that NtsR1 may exert distinct roles within development vs. adulthood, we then examined the impact of adult-onset deletion of NtsR1 from VTA DA neurons. We injected adult NtsR1flox/flox mice in the VTA with adeno associated virus to Cre-dependently delete NtsR1 in the VTA (VTAR1Null mice) and compared them to mice with intact NtsR1 (Controls). Again, in contrast to our hypothesis, VTAR1Null mice gained less weight than Controls while on normal chow or high fat diets. Moreover, VTAR1Null mice exhibited blunted feeding after fasting, suggesting a role for NtsR1 in adult VTA DA neurons in coordinating energy need and intake. Altogether, these data suggest that intact expression of NtsR1 in DA neurons is necessary for appropriate regulation of body weight, but a lack of NtsR1 in the developing vs. adult DA system protects from weight gain via different mechanisms. These findings emphasize the need for temporal and site-specific resolution to fully understand the role of NtsR1 within the brain.
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Affiliation(s)
- Patricia Perez-Bonilla
- Neuroscience Graduate Program, Michigan State University, East Lansing, MI, United States
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, MI, United States
| | - Jariel Ramirez-Virella
- Neuroscience Graduate Program, Michigan State University, East Lansing, MI, United States
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, MI, United States
| | - Pooja Menon
- Department of Physiology, Michigan State University, East Lansing, MI, United States
| | - Eva Troyano-Rodriguez
- Aging and Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, United States
| | - Sydney K. Arriaga
- Department of Physiology, Michigan State University, East Lansing, MI, United States
| | - Anna Makela
- Department of Physiology, Michigan State University, East Lansing, MI, United States
| | - Raluca Bugescu
- Department of Physiology, Michigan State University, East Lansing, MI, United States
| | - Michael J. Beckstead
- Aging and Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, United States
- Oklahoma City Veterans Affairs Medical Center, Oklahoma City, OK, United States
| | - Gina M. Leinninger
- Department of Physiology, Michigan State University, East Lansing, MI, United States
- *Correspondence: Gina M. Leinninger,
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12
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Sharpe AL, Trzeciak M, Eliason NL, Blankenship HE, Byrd BM, Douglas PD, Freeman WM, Beckstead MJ. Repeated cocaine or methamphetamine treatment alters astrocytic CRF2 and GLAST expression in the ventral midbrain. Addict Biol 2022; 27:e13120. [PMID: 34825430 PMCID: PMC9872560 DOI: 10.1111/adb.13120] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2021] [Revised: 11/02/2021] [Accepted: 11/04/2021] [Indexed: 01/26/2023]
Abstract
Dopamine neurons in the substantia nigra (SN) and ventral tegmental area (VTA) play a central role in the reinforcing properties of abused drugs including methamphetamine and cocaine. Chronic effects of psychostimulants in the SN/VTA also involve non-dopaminergic transmitters, including glutamate and the stress-related peptide corticotropin-releasing factor (CRF). In the SN/VTA, astrocytes express a variety of membrane-bound neurotransmitter receptors and transporters that influence neurotransmission. CRF receptor type 2 (CRF2) activity in the VTA is important for stress-induced relapse and drug-seeking behaviour, but the localization of its effects is incompletely understood. Here, we first identified CRF2 transcript in astrocytes of the SN/VTA using RNA-Seq in Aldh1l1;NuTRAP mice and confirmed it using in situ hybridization (RNAscope) in wild-type mice. We then used immunofluorescence to quantify the astrocytic marker protein S100β, glial-specific glutamate/aspartate transporter GLAST, and CRF2 in the SN/VTA following 12 days of treatment (i.p.) with methamphetamine (3 mg/kg), cocaine (10 mg/kg), or saline. We observed a significant decrease in GLAST immunofluorescence in brains of psychostimulant treated mice compared with saline controls. In addition, we observed increased labelling of CRF2 in drug treated groups, a decrease in the number of S100β positive cells, and an increase of co-staining of CRF2 with both S100β and tyrosine hydroxylase (dopamine neurons). Our results suggest a significant interaction between CRF2, GLAST, and astrocytes in the midbrain that emerges with repeated exposure to psychostimulants. These findings provide rationale for future investigation of astrocyte-based strategies for altering cellular and circuit function in response to stress and drug exposure.
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Affiliation(s)
- Amanda L. Sharpe
- Department of Pharmaceutical Sciences, University of Oklahoma College of Pharmacy, Oklahoma City, OK, 73117
| | - Marta Trzeciak
- Aging & Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, 73104
| | - Nicole L. Eliason
- Department of Pharmaceutical Sciences, University of Oklahoma College of Pharmacy, Oklahoma City, OK, 73117
| | - Harris E. Blankenship
- Aging & Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, 73104
| | - Bre’Ana M. Byrd
- Department of Pharmaceutical Sciences, University of Oklahoma College of Pharmacy, Oklahoma City, OK, 73117
| | - Phillip D. Douglas
- Aging & Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, 73104
| | - Willard M. Freeman
- Genes & Human Disease Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, 73104
| | - Michael J. Beckstead
- Aging & Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, 73104
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13
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Beckstead MJ, Howell RD. Progressive parkinsonism due to mitochondrial impairment: Lessons from the MitoPark mouse model. Exp Neurol 2021; 341:113707. [PMID: 33753138 PMCID: PMC8169575 DOI: 10.1016/j.expneurol.2021.113707] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Revised: 03/17/2021] [Accepted: 03/18/2021] [Indexed: 12/21/2022]
Abstract
The cardinal pathophysiological finding of Parkinson's disease (PD) is a chronic, progressive degeneration of dopamine (DA) neurons in the substantia nigra, which is responsible for the motor and some of the non-motor symptomatology. While the primary causes of nigrostriatal degeneration are hotly debated, considerable evidence supports a central role for impaired mitochondrial function. Postmortem analysis of PD patients reveals impaired respiratory chains and increased mutations of mitochondrial DNA (mtDNA), in addition to increased markers of oxidative stress indicative of mitochondrial impairment. Most animal models of PD, both genetic and toxin-based, target some component of mitochondrial function to reproduce aspects of the human disease. One model that continues to gain attention is the MitoPark mouse, created through a cell type-specific knockout of mitochondrial transcription factor A specifically in midbrain DA neurons. This model effectively recapitulates the slowly developing, adult onset motor decline seen in PD due to mass loss of DA neurons. MitoPark mice therefore represent an effective tool for studying the sequence of events that occurs in the early stages of DA neuron degeneration following mitochondrial impairment, as well as for testing the efficacy of potential disease-modifying therapies in a progressive model of neurodegeneration. A targeted review of key findings from MitoPark mice has not been published since the early years following the initial report of the model in 2007. The current review synthesizes findings from several groups that are exploring MitoPark mice and discusses implications for the future identification of disease-modifying treatments for PD.
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Affiliation(s)
- Michael J Beckstead
- Oklahoma Medical Research Foundation, Aging & Metabolism Research Program, USA.
| | - Rebecca D Howell
- Oklahoma Medical Research Foundation, Aging & Metabolism Research Program, USA
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14
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Dominguez‐Lopez S, Sharma R, Beckstead MJ. Neurotensin receptor 1 deletion decreases methamphetamine self-administration and the associated reduction in dopamine cell firing. Addict Biol 2021; 26:e12854. [PMID: 31742874 DOI: 10.1111/adb.12854] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2019] [Revised: 09/26/2019] [Accepted: 10/28/2019] [Indexed: 12/26/2022]
Abstract
We previously reported that a non-selective pharmacological blockade of neurotensin receptors in the ventral tegmental area (VTA) decreases methamphetamine (METH) self-administration in mice. Here, we explored the consequences of genetic deletion of neurotensin receptor 1 (NtsR1) on METH self-administration and VTA dopamine neuron firing activity. We implanted mice with an indwelling jugular catheter and trained them to nose-poke for intravenous infusions of METH. Mice with NtsR1 deletion (KO) acquired self-administration similar to wildtype (WT) and heterozygous (HET) littermates. However, in NtsR1 KO and HET mice, METH intake and motivated METH seeking decreased when the response requirement was increased to a fixed ratio 3 and when mice were tested on a progressive ratio protocol. After completion of METH self-administration, single cell in vivo extracellular recordings of dopamine firing activity in the VTA were obtained in anesthetized mice. Non-bursting dopamine neurons from KO mice fired at slower rates than those from WT mice, supporting an excitatory role for NtsR1 on VTA dopamine neuronal activity. In WT mice, a history of METH self-administration decreased dopamine cell firing frequency compared with cells from drug-naïve controls. NtsR1 KO and HET mice did not exhibit this decline in dopamine cell firing activity after METH experience. We also observed an increase in population activity following METH self-administration that was strongest in the WT group. Our results suggest a role for NtsR1 in METH-seeking behavior and indicate that ablation of NtsR1 prevents the detrimental effects of prolonged METH self-administration on VTA dopamine cell firing frequency.
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Affiliation(s)
- Sergio Dominguez‐Lopez
- Aging & Metabolism Research Program, Oklahoma Medical Research Foundation Oklahoma City OK USA
| | - Ramaswamy Sharma
- Department of Cell Systems & Anatomy, UT Health San Antonio San Antonio TX USA
| | - Michael J. Beckstead
- Aging & Metabolism Research Program, Oklahoma Medical Research Foundation Oklahoma City OK USA
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15
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Chucair-Elliott AJ, Ocañas SR, Stanford DR, Ansere VA, Buettner KB, Porter H, Eliason NL, Reid JJ, Sharpe AL, Stout MB, Beckstead MJ, Miller BF, Richardson A, Freeman WM. Inducible cell-specific mouse models for paired epigenetic and transcriptomic studies of microglia and astroglia. Commun Biol 2020; 3:693. [PMID: 33214681 PMCID: PMC7678837 DOI: 10.1038/s42003-020-01418-x] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Accepted: 10/23/2020] [Indexed: 12/24/2022] Open
Abstract
Epigenetic regulation of gene expression occurs in a cell type-specific manner. Current cell-type specific neuroepigenetic studies rely on cell sorting methods that can alter cell phenotype and introduce potential confounds. Here we demonstrate and validate a Nuclear Tagging and Translating Ribosome Affinity Purification (NuTRAP) approach for temporally controlled labeling and isolation of ribosomes and nuclei, and thus RNA and DNA, from specific central nervous system cell types. Analysis of gene expression and DNA modifications in astrocytes or microglia from the same animal demonstrates differential usage of DNA methylation and hydroxymethylation in CpG and non-CpG contexts that corresponds to cell type-specific gene expression. Application of this approach in LPS treated mice uncovers microglia-specific transcriptome and epigenome changes in inflammatory pathways that cannot be detected with tissue-level analysis. The NuTRAP model and the validation approaches presented can be applied to any brain cell type for which a cell type-specific cre is available. Ana Chucair-Elliott, Sarah Ocaňas et al. present a NuTRAP approach for simultaneous analysis of transcript expression and DNA modifications in two specific mouse brain cell types, astrocytes and microglia. They further apply this approach to identify molecular changes in microglia following LPS treatment and identify both transcriptomic and epigenomic alterations not apparent in tissue-level analyses.
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Affiliation(s)
- Ana J Chucair-Elliott
- Genes & Human Disease Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA
| | - Sarah R Ocañas
- Genes & Human Disease Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA.,Department of Physiology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - David R Stanford
- Genes & Human Disease Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA
| | - Victor A Ansere
- Genes & Human Disease Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA.,Department of Physiology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Kyla B Buettner
- Genes & Human Disease Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA.,Department of Physiology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Hunter Porter
- Genes & Human Disease Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA.,Oklahoma Center for Neuroscience, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Nicole L Eliason
- Department of Pharmaceutical Sciences, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Justin J Reid
- Aging & Metabolism Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA
| | - Amanda L Sharpe
- Department of Pharmaceutical Sciences, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Michael B Stout
- Department of Nutritional Sciences, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Michael J Beckstead
- Aging & Metabolism Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA
| | - Benjamin F Miller
- Aging & Metabolism Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA
| | - Arlan Richardson
- Department of Biochemistry, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA.,Oklahoma City Veterans Affairs Medical Center, Oklahoma City, OK, USA
| | - Willard M Freeman
- Genes & Human Disease Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA. .,Department of Biochemistry, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA. .,Oklahoma City Veterans Affairs Medical Center, Oklahoma City, OK, USA.
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16
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Howell RD, Dominguez-Lopez S, Ocañas SR, Freeman WM, Beckstead MJ. Female mice are resilient to age-related decline of substantia nigra dopamine neuron firing parameters. Neurobiol Aging 2020; 95:195-204. [PMID: 32846275 DOI: 10.1016/j.neurobiolaging.2020.07.025] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Revised: 06/03/2020] [Accepted: 07/25/2020] [Indexed: 02/06/2023]
Abstract
Degeneration of substantia nigra pars compacta dopamine neurons is a central feature in the pathology of Parkinson's disease, which is characterized by progressive loss of motor and cognitive functions. The largest risk factors for Parkinson's disease are age and sex; most cases occur after age 60 and males have nearly twice the incidence as females. Preclinical work has scarcely considered the influence of these 2 factors to disease risk and presentation. Here, we observed a progressive decline in dopamine neuron firing activity in male C57BL/6 mice by 18 months of age, while dopamine neurons from females remained largely unaffected. This was accompanied by increased mRNA expression of PINK1 in both males and females, and PARK2 primarily in males, both of which have been linked to Parkinson's. Since the declining cell properties were accompanied by only slight decreases in locomotion in both sexes, it is likely that these age-related impairments in males represent a vulnerability to further insults that could predispose the neurons to neurodegenerative processes such as in Parkinson's.
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Affiliation(s)
- Rebecca D Howell
- Aging & Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK; Department of Physiology, University of Oklahoma Health Sciences Center, Oklahoma City, OK
| | - Sergio Dominguez-Lopez
- Aging & Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK
| | - Sarah R Ocañas
- Department of Physiology, University of Oklahoma Health Sciences Center, Oklahoma City, OK; Genes & Human Disease Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK
| | - Willard M Freeman
- Department of Physiology, University of Oklahoma Health Sciences Center, Oklahoma City, OK
| | - Michael J Beckstead
- Aging & Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK.
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17
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Tschumi CW, Daszkowski AW, Sharpe AL, Trzeciak M, Beckstead MJ. A history of ethanol drinking increases locomotor stimulation and blunts enhancement of dendritic dopamine transmission by methamphetamine. Addict Biol 2020; 25:e12763. [PMID: 31062485 DOI: 10.1111/adb.12763] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2018] [Revised: 02/15/2019] [Accepted: 03/22/2019] [Indexed: 12/19/2022]
Abstract
Ethanol and psychostimulant use disorders exhibit comorbidity in humans and cross-sensitization in animal models, but the neurobiological underpinnings of this are not well understood. Ethanol acutely increases dopamine neuron excitability, and psychostimulants such as cocaine or methamphetamine increase extracellular dopamine through inhibition of uptake through the dopamine transporter (DAT) and/or vesicular monoamine transporter 2 (VMAT2). Psychostimulants also depress dopamine neuron activity by enhancing dendritic dopamine neurotransmission. Here, we show that mice with a previous history of ethanol drinking are more sensitive to the locomotor-stimulating effects of a high dose (5 mg/kg), but not lower doses (1 and 3 mg/kg) of methamphetamine or any tested dose of cocaine (3, 10, and 18 mg/kg), compared with water-drinking controls. We next investigated the impact of a history of ethanol drinking, in a separate group of mice, on methamphetamine- or cocaine-induced enhancement of dendritic dopamine transmission using whole-cell voltage clamp electrophysiology in mouse brain slices. Methamphetamine, applied at a concentration (10 μM) that affects both DAT and VMAT2, enhanced D2 receptor-mediated inhibitory postsynaptic currents (D2-IPSCs) in both groups, but this effect was blunted in mice with a history of ethanol drinking. As methamphetamine action at VMAT2 disrupts dopamine neurotransmission, these results may suggest enhanced action of methamphetamine at VMAT2. Furthermore, there were no differences in low-dose methamphetamine or cocaine-induced enhancement of D2-IPSCs, suggesting intact DAT function. Disruption of methamphetamine-induced enhancement of dendritic dopamine transmission would result in decreased inhibition of dopamine neurons, ultimately increasing downstream release and the behavioral effects of methamphetamine.
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Affiliation(s)
- Christopher W. Tschumi
- Aging and Metabolism Research Program Oklahoma Medical Research Foundation Oklahoma City Oklahoma USA
- Department of Cellular and Integrative Physiology University of Texas Health Science Center at San Antonio San Antonio Texas USA
| | - Anna W. Daszkowski
- Department of Cellular and Integrative Physiology University of Texas Health Science Center at San Antonio San Antonio Texas USA
| | - Amanda L. Sharpe
- Department of Pharmaceutical Sciences University of Oklahoma Health Sciences Center Oklahoma City Oklahoma USA
| | - Marta Trzeciak
- Aging and Metabolism Research Program Oklahoma Medical Research Foundation Oklahoma City Oklahoma USA
| | - Michael J. Beckstead
- Aging and Metabolism Research Program Oklahoma Medical Research Foundation Oklahoma City Oklahoma USA
- Department of Cellular and Integrative Physiology University of Texas Health Science Center at San Antonio San Antonio Texas USA
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18
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Newman AH, Cao J, Keighron JD, Jordan CJ, Bi GH, Liang Y, Abramyan AM, Avelar AJ, Tschumi CW, Beckstead MJ, Shi L, Tanda G, Xi ZX. Translating the atypical dopamine uptake inhibitor hypothesis toward therapeutics for treatment of psychostimulant use disorders. Neuropsychopharmacology 2019; 44:1435-1444. [PMID: 30858517 PMCID: PMC6785152 DOI: 10.1038/s41386-019-0366-z] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Revised: 02/27/2019] [Accepted: 02/27/2019] [Indexed: 11/10/2022]
Abstract
Medication-assisted treatments are unavailable to patients with cocaine use disorders. Efforts to develop potential pharmacotherapies have led to the identification of a promising lead molecule, JJC8-091, that demonstrates a novel binding mode at the dopamine transporter (DAT). Here, JJC8-091 and a structural analogue, JJC8-088, were extensively and comparatively assessed to elucidate neurochemical correlates to their divergent behavioral profiles. Despite sharing significant structural similarity, JJC8-088 was more cocaine-like, increasing extracellular DA concentrations in the nucleus accumbens shell (NAS) efficaciously and more potently than JJC8-091. In contrast, JJC8-091 was not self-administered and was effective in blocking cocaine-induced reinstatement to drug seeking. Electrophysiology experiments confirmed that JJC8-091 was more effective than JJC8-088 at inhibiting cocaine-mediated enhancement of DA neurotransmission. Further, when VTA DA neurons in DAT-cre mice were optically stimulated, JJC8-088 produced a significant leftward shift in the stimulation-response curve, similar to cocaine, while JJC8-091 shifted the curve downward, suggesting attenuation of DA-mediated brain reward. Computational models predicted that JJC8-088 binds in an outward facing conformation of DAT, similar to cocaine. Conversely, JJC8-091 steers DAT towards a more occluded conformation. Collectively, these data reveal the underlying molecular mechanism at DAT that may be leveraged to rationally optimize leads for the treatment of cocaine use disorders, with JJC8-091 representing a compelling candidate for development.
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Affiliation(s)
- Amy Hauck Newman
- Molecular Targets and Medications Discovery Branch, National Institute on Drug Abuse, Intramural Research Program, National Institutes of Health, 333 Cassell Drive, Baltimore, MD, 21224, USA.
| | - Jianjing Cao
- 0000 0004 1936 8075grid.48336.3aMolecular Targets and Medications Discovery Branch, National Institute on Drug Abuse, Intramural Research Program, National Institutes of Health, 333 Cassell Drive, Baltimore, MD 21224 USA
| | - Jacqueline D. Keighron
- 0000 0004 1936 8075grid.48336.3aMolecular Targets and Medications Discovery Branch, National Institute on Drug Abuse, Intramural Research Program, National Institutes of Health, 333 Cassell Drive, Baltimore, MD 21224 USA
| | - Chloe J. Jordan
- 0000 0004 1936 8075grid.48336.3aMolecular Targets and Medications Discovery Branch, National Institute on Drug Abuse, Intramural Research Program, National Institutes of Health, 333 Cassell Drive, Baltimore, MD 21224 USA
| | - Guo-Hua Bi
- 0000 0004 1936 8075grid.48336.3aMolecular Targets and Medications Discovery Branch, National Institute on Drug Abuse, Intramural Research Program, National Institutes of Health, 333 Cassell Drive, Baltimore, MD 21224 USA
| | - Ying Liang
- 0000 0004 1936 8075grid.48336.3aMolecular Targets and Medications Discovery Branch, National Institute on Drug Abuse, Intramural Research Program, National Institutes of Health, 333 Cassell Drive, Baltimore, MD 21224 USA
| | - Ara M. Abramyan
- 0000 0004 1936 8075grid.48336.3aMolecular Targets and Medications Discovery Branch, National Institute on Drug Abuse, Intramural Research Program, National Institutes of Health, 333 Cassell Drive, Baltimore, MD 21224 USA
| | - Alicia J. Avelar
- 0000 0001 0629 5880grid.267309.9Department of Cellular and Integrative Physiology, UT Health Science Center, San Antonio, TX USA
| | - Christopher W. Tschumi
- 0000 0001 0629 5880grid.267309.9Department of Cellular and Integrative Physiology, UT Health Science Center, San Antonio, TX USA ,0000 0000 8527 6890grid.274264.1Aging & Metabolism Research Group, Oklahoma Medical Research Foundation, Oklahoma City, OK USA
| | - Michael J. Beckstead
- 0000 0001 0629 5880grid.267309.9Department of Cellular and Integrative Physiology, UT Health Science Center, San Antonio, TX USA ,0000 0000 8527 6890grid.274264.1Aging & Metabolism Research Group, Oklahoma Medical Research Foundation, Oklahoma City, OK USA
| | - Lei Shi
- 0000 0004 1936 8075grid.48336.3aMolecular Targets and Medications Discovery Branch, National Institute on Drug Abuse, Intramural Research Program, National Institutes of Health, 333 Cassell Drive, Baltimore, MD 21224 USA
| | - Gianluigi Tanda
- 0000 0004 1936 8075grid.48336.3aMolecular Targets and Medications Discovery Branch, National Institute on Drug Abuse, Intramural Research Program, National Institutes of Health, 333 Cassell Drive, Baltimore, MD 21224 USA
| | - Zheng-Xiong Xi
- 0000 0004 1936 8075grid.48336.3aMolecular Targets and Medications Discovery Branch, National Institute on Drug Abuse, Intramural Research Program, National Institutes of Health, 333 Cassell Drive, Baltimore, MD 21224 USA
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19
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Parikh I, Lopez SD, Howell RD, Beckstead MJ. Age‐Related Dysregulation of Neuronal Activity in Single Dopaminergic Neurons. FASEB J 2019. [DOI: 10.1096/fasebj.2019.33.1_supplement.737.4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Ishita Parikh
- Aging and MetabolismOklahoma Medical Research FoundationOklahoma CityOK
| | | | - Rebecca D. Howell
- Aging and MetabolismOklahoma Medical Research FoundationOklahoma CityOK
- University of Oklahoma Health Science CenterOklahoma CityOK
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Lopez SD, Ahn B, Premkumar P, Van Remmen H, Beckstead MJ. Mitochondrial Oxidative Metabolism and Dopamine Neurodegeneration in the Mesolimbic Pathway after Prolonged Methamphetamine Self‐Administration in Mice. FASEB J 2019. [DOI: 10.1096/fasebj.2019.33.1_supplement.805.17] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
| | - Bumsoo Ahn
- Aging and MetabolismOklahoma Medical Research FoundationOklahoma CityOK
| | | | - Holly Van Remmen
- Aging and MetabolismOklahoma Medical Research FoundationOklahoma CityOK
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Trzeciak M, Sharpe AL, Douglas P, Beckstead MJ. Methamphetamine and cocaine administration increases CRF‐R2 and decreases S100‐beta astrocytic immunoreactivity in the VTA. FASEB J 2019. [DOI: 10.1096/fasebj.2019.33.1_supplement.805.16] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Marta Trzeciak
- Aging and Metabolism Research ProgramOklahoma Medical Research FoundationOklahoma CityOK
| | - Amanda L. Sharpe
- Aging and Metabolism Research ProgramOklahoma Medical Research FoundationOklahoma CityOK
- Department of Pharmaceutical SciencesUniversity of Oklahoma College of PharmacyOklahoma CityOK
| | - Phillip Douglas
- Aging and Metabolism Research ProgramOklahoma Medical Research FoundationOklahoma CityOK
| | - Michael J. Beckstead
- Aging and Metabolism Research ProgramOklahoma Medical Research FoundationOklahoma CityOK
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22
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Piccart E, Tschumi CW, Beckstead MJ. Acute and subchronic PCP attenuate D2 autoreceptor signaling in substantia nigra dopamine neurons. Eur Neuropsychopharmacol 2019; 29:444-449. [PMID: 30686631 PMCID: PMC6421099 DOI: 10.1016/j.euroneuro.2019.01.108] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/06/2017] [Revised: 01/09/2019] [Accepted: 01/14/2019] [Indexed: 11/17/2022]
Abstract
Phencyclidine (PCP) administration is commonly used to model schizophrenia in laboratory animals. While PCP is well-characterized as an antagonist of glutamate-sensitive N-methyl-D-aspartate (NMDA) receptors, its effects on dopamine signaling are not well understood. Here we used whole-cell and cell-attached patch-clamp electrophysiology of substantia nigra dopamine neurons to determine the effects of acute and subchronic PCP exposure on both dopamine D2 autoreceptor-mediated currents and burst firing evoked by glutamate receptor activation. Acute PCP affected D2 autoreceptor-mediated currents through two apparently distinct mechanisms: a low-concentration dopamine transporter (DAT) inhibition and a high-concentration potassium (GIRK) channel inhibition. Subchronic administration of PCP (5 mg/kg, i.p., every 12 h for 7 days) decreased sensitivity to low dopamine concentrations, and also enhanced evoked burst firing of dopamine neurons. These findings suggest the effects of PCP on dopaminergic signaling in the midbrain could enhance burst firing and contribute to the development of schizophreniform behavior.
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Affiliation(s)
| | - Christopher W Tschumi
- Oklahoma Medical Research Foundation, Aging & Metabolism Research Program, Oklahoma City, OK 73104, USA; University of Texas Health, San Antonio, Department of Cellular & Integrative Physiology, San Antonio, TX 78228, USA
| | - Michael J Beckstead
- Oklahoma Medical Research Foundation, Aging & Metabolism Research Program, Oklahoma City, OK 73104, USA; University of Texas Health, San Antonio, Department of Cellular & Integrative Physiology, San Antonio, TX 78228, USA.
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Lynch WB, Tschumi CW, Sharpe AL, Branch SY, Chen C, Ge G, Li S, Beckstead MJ. Progressively disrupted somatodendritic morphology in dopamine neurons in a mouse Parkinson's model. Mov Disord 2018; 33:1928-1937. [PMID: 30440089 DOI: 10.1002/mds.27541] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2018] [Revised: 08/10/2018] [Accepted: 09/16/2018] [Indexed: 12/26/2022] Open
Abstract
BACKGROUND Parkinson's disease is characterized by the progressive loss of dopamine neurons in the substantia nigra, leading to severe motor deficits. Although the disease likely begins to develop years before observable motor symptoms, the specific morphological and functional alterations involved are poorly understood. OBJECTIVES MitoPark mice lack the gene coding for mitochondrial transcription factor A specifically in dopamine neurons, which over time produces a progressive decline of neuronal function and related behavior that phenotypically mirrors human parkinsonism. Our previous work identified a progressive decrease in cell capacitance in dopamine neurons from MitoPark mice, possibly suggesting reduced membrane surface area. We therefore sought to identify and quantify somatodendritic parameters in this model across age. METHODS We used whole-cell patch clamp and fluorescent labeling to quantify somatodendritic morphology of single, neurobiotin-filled dopamine neurons in acutely isolated brain slices from MitoPark mice. RESULTS We found that MitoPark mice exhibit an adult-onset, age-dependent reduction of neuritic branching and soma size in dopamine neurons. This decline proceeds similarly in MitoPark mice of both sexes, but does not begin until after the age that early decrements in ion channel physiology and behavior have previously been observed. CONCLUSIONS A progressive and severe decline in somatodendritic morphology occurs prior to cell death, but is not responsible for the subtle decrements observable in the earliest stages of neurodegeneration. This work could help identify the ideal time window for specific treatments to halt disease progression and avert debilitating motor deficits in Parkinson's patients. © 2018 International Parkinson and Movement Disorder Society.
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Affiliation(s)
- William B Lynch
- Aging and Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma, USA
| | - Christopher W Tschumi
- Aging and Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma, USA.,Department of Cellular and Integrative Physiology, University of Texas Health, San Antonio, Texas, USA
| | - Amanda L Sharpe
- Aging and Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma, USA.,Department of Pharmaceutical Sciences, University of Oklahoma College of Pharmacy, Oklahoma City, Oklahoma, USA
| | - Sarah Y Branch
- Department of Cellular and Integrative Physiology, University of Texas Health, San Antonio, Texas, USA
| | - Cang Chen
- Department of Medicine, University of Texas Health, San Antonio, Texas, USA
| | - Guo Ge
- Department of Medicine, University of Texas Health, San Antonio, Texas, USA
| | - Senlin Li
- Department of Medicine, University of Texas Health, San Antonio, Texas, USA
| | - Michael J Beckstead
- Aging and Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma, USA.,Department of Cellular and Integrative Physiology, University of Texas Health, San Antonio, Texas, USA
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24
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Dominguez-Lopez S, Piccart E, Lynch WB, Wollet MB, Sharpe AL, Beckstead MJ. Antagonism of Neurotensin Receptors in the Ventral Tegmental Area Decreases Methamphetamine Self-Administration and Methamphetamine Seeking in Mice. Int J Neuropsychopharmacol 2018; 21:361-370. [PMID: 29272412 PMCID: PMC5888879 DOI: 10.1093/ijnp/pyx117] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/07/2017] [Revised: 12/13/2017] [Accepted: 12/18/2017] [Indexed: 12/24/2022] Open
Abstract
Background Neurotensin is a peptide that modulates central dopamine neurotransmission and dopamine-related behaviors. Methamphetamine self-administration increases neurotensin levels in the ventral tegmental area, but the consequences for self-administration behavior have not been described. Here we test the hypothesis that antagonizing neurotensin receptors in the ventral tegmental area attenuates the acquisition of methamphetamine self-administration and methamphetamine intake. Methods We implanted mice with an indwelling catheter in the right jugular vein and bilateral cannulae directed at the ventral tegmental area. Mice were then trained to nose-poke for i.v. infusions of methamphetamine (0.1 mg/kg/infusion) on a fixed ratio 3 schedule. Results Mice receiving microinfusions of the neurotensin NTS1/NTS2 receptor antagonist SR142948A in the ventral tegmental area (10 ng/side) prior to the first 5 days of methamphetamine self-administration required more sessions to reach acquisition criteria. Methamphetamine intake was decreased in SR142948A-treated mice both during training and later during maintenance of self-administration. Drug seeking during extinction, cue-induced reinstatement, and progressive ratio schedules was also reduced in the SR142948A group. The effects of SR142948A were not related to changes in basal locomotor activity or methamphetamine psychomotor properties. In both SR142948A- and saline-treated mice, a strong positive correlation between methamphetamine intake and enhanced locomotor activity was observed. Conclusion Our results suggest that neurotensin input in the ventral tegmental area during initial methamphetamine exposure contributes to the acquisition of methamphetamine self-administration and modulates later intake and methamphetamine-seeking behavior in mice. Furthermore, our results highlight the role of endogenous neurotensin in the ventral tegmental area in the reinforcing efficacy of methamphetamine, independent of its psychomotor effects.
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Affiliation(s)
- Sergio Dominguez-Lopez
- Aging & Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK
- Department of Cellular and Integrative Physiology, University of Texas Health, San Antonio, Texas
| | - Elisabeth Piccart
- Department of Cellular and Integrative Physiology, University of Texas Health, San Antonio, Texas
| | - William B Lynch
- Aging & Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK
- Department of Cellular and Integrative Physiology, University of Texas Health, San Antonio, Texas
| | - Mackenna B Wollet
- Department of Cellular and Integrative Physiology, University of Texas Health, San Antonio, Texas
| | - Amanda L Sharpe
- Department of Pharmaceutical Sciences, Feik School of Pharmacy, University of the Incarnate Word, San Antonio, Texas
- College of Pharmacy, University of Oklahoma Health Sciences Center, Oklahoma City, OK
| | - Michael J Beckstead
- Aging & Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK
- Department of Cellular and Integrative Physiology, University of Texas Health, San Antonio, Texas
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25
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Tschumi CW, Beckstead MJ. D2 Autoreceptor Signaling is Depressed by Neurotensin Released from Discrete Inputs to Midbrain Dopamine Neurons. FASEB J 2018. [DOI: 10.1096/fasebj.2018.32.1_supplement.680.7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Christopher W. Tschumi
- Aging and Metabolism Research ProgramOklahoma Medical Research FoundationOklahoma CityOK
- Department of Cellular and Integrative PhysiologyUniversity of Texas Health Science CenterSan AnotnioSan AntonioTX
| | - Michael J. Beckstead
- Aging and Metabolism Research ProgramOklahoma Medical Research FoundationOklahoma CityOK
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Tschumi CW, Beckstead MJ. Diverse actions of the modulatory peptide neurotensin on central synaptic transmission. Eur J Neurosci 2018; 49:784-793. [PMID: 29405480 DOI: 10.1111/ejn.13858] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2017] [Revised: 01/29/2018] [Accepted: 01/30/2018] [Indexed: 12/27/2022]
Abstract
Neurotensin (NT) is a 13 amino acid neuropeptide that is expressed throughout the central nervous system and is implicated in the etiology of multiple diseases and disorders. Many primary investigations of NT-induced modulation of neuronal excitability at the level of the synapse have been conducted, but they have not been summarized in review form in nearly 30 years. Therefore, the goal of this review is to discuss the many actions of NT on neuronal excitability across brain regions as well as NT circuit architecture. In the basal ganglia as well as other brain nuclei, NT can act through diverse intracellular signaling cascades to enhance or depress neuronal activity by modulating activity of ion channels, ionotropic and metabotropic neurotransmitter receptors, and presynaptic release of neurotransmitters. Further, NT can produce indirect effects by evoking endocannabinoid release, and recently has itself been identified as a putative retrograde messenger. In the basal ganglia, the diverse actions and circuit architecture of NT signaling allow for input-specific control of reward-related behaviors.
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Affiliation(s)
- Christopher W Tschumi
- Aging & Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, 73104-5005, USA
| | - Michael J Beckstead
- Aging & Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, 73104-5005, USA
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Tschumi CW, Beckstead MJ. Neurotensin speeds inhibition of dopamine neurons through temporal modulation of GABA A and GABA B receptor-mediated synaptic input. Neuropharmacology 2018; 131:414-423. [PMID: 29307543 DOI: 10.1016/j.neuropharm.2018.01.004] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2017] [Revised: 12/02/2017] [Accepted: 01/02/2018] [Indexed: 01/20/2023]
Abstract
Midbrain dopamine neurons play physiological roles in many processes including reward learning and motivated behavior, and are tonically inhibited by γ-aminobutyric acid (GABA)ergic input from multiple brain regions. Neurotensin (NT) is a neuropeptide which acutely modulates midbrain dopamine neuron excitability through multiple mechanisms, one of which is a decrease of GABA-mediated inhibition. However, the mechanisms through which NT depresses GABA signaling are not known. Here we used whole cell patch-clamp electrophysiology of dopamine neurons in mouse brain slices to show that NT acts both presynaptically to increase GABAA and postsynaptically to decrease GABAB receptor-mediated currents in the substantia nigra. The active peptide fragment NT8-13 enhanced GABAA signaling presynaptically by causing an increase in the size of the readily releasable pool of GABA via activation of the NT type-1 receptor and protein kinase A. Conversely, NT8-13 depressed GABAB signaling postsynaptically via the NT type-2 receptor in a process that was modulated by protein kinase C. Both forms of plasticity could be observed simultaneously in single dopamine neurons. Thus, as the kinetics of GABAA signaling are significantly faster than those of GABAB signaling, NT functionally speeds GABAergic input to midbrain dopamine neurons. This finding contributes to our understanding of how neuropeptide-induced plasticity can simultaneously differentiate and integrate signaling by a single neurotransmitter in a single cell and provides a basis for understanding how neuropeptides use temporal shifts in synaptic strength to encode information.
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Affiliation(s)
- Christopher W Tschumi
- Aging and Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, 73104-5005, USA; Department of Cellular and Integrative Physiology, University of Texas Health, San Antonio, San Antonio, TX, 78229, USA
| | - Michael J Beckstead
- Aging and Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, 73104-5005, USA; Department of Cellular and Integrative Physiology, University of Texas Health, San Antonio, San Antonio, TX, 78229, USA.
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Donegan JJ, Tyson JA, Branch SY, Beckstead MJ, Anderson SA, Lodge DJ. Stem cell-derived interneuron transplants as a treatment for schizophrenia: preclinical validation in a rodent model. Mol Psychiatry 2017; 22:1492-1501. [PMID: 27480492 PMCID: PMC5290293 DOI: 10.1038/mp.2016.121] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/15/2015] [Revised: 06/17/2016] [Accepted: 06/21/2016] [Indexed: 01/28/2023]
Abstract
An increasing literature suggests that schizophrenia is associated with a reduction in hippocampal interneuron function. Thus, we posit that stem cell-derived interneuron transplants may be an effective therapeutic strategy to reduce hippocampal hyperactivity and attenuate behavioral deficits in schizophrenia. Here we used a dual-reporter embryonic stem cell line to generate enriched populations of parvalbumin (PV)- or somatostatin (SST)-positive interneurons, which were transplanted into the ventral hippocampus of the methylazoxymethanol rodent model of schizophrenia. These interneuron transplants integrate within the existing circuitry, reduce hippocampal hyperactivity and normalize aberrant dopamine neuron activity. Further, interneuron transplants alleviate behaviors that model negative and cognitive symptoms, including deficits in social interaction and cognitive inflexibility. Interestingly, PV- and SST-enriched transplants produced differential effects on behavior, with PV-enriched populations effectively normalizing all the behaviors examined. These data suggest that the stem cell-derived interneuron transplants may represent a novel therapeutic strategy for schizophrenia.
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Affiliation(s)
- J J Donegan
- Department of Pharmacology and Center for Biomedical Neuroscience, University of Texas Health Science Center, San Antonio, TX, USA
| | - J A Tyson
- Department of Psychiatry, Children's Hospital of Philadelphia, University of Pennsylvania School of Medicine, Philadelphia, PA, USA
| | - S Y Branch
- Department of Physiology and Center for Biomedical Neuroscience, University of Texas Health Science Center, San Antonio, TX, USA
| | - M J Beckstead
- Department of Physiology and Center for Biomedical Neuroscience, University of Texas Health Science Center, San Antonio, TX, USA
| | - S A Anderson
- Department of Psychiatry, Children's Hospital of Philadelphia, University of Pennsylvania School of Medicine, Philadelphia, PA, USA
| | - D J Lodge
- Department of Pharmacology and Center for Biomedical Neuroscience, University of Texas Health Science Center, San Antonio, TX, USA
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29
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Avelar AJ, Cao J, Newman AH, Beckstead MJ. Atypical dopamine transporter inhibitors R-modafinil and JHW 007 differentially affect D2 autoreceptor neurotransmission and the firing rate of midbrain dopamine neurons. Neuropharmacology 2017. [PMID: 28625719 DOI: 10.1016/j.neuropharm.2017.06.016] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Abuse of psychostimulants like cocaine that inhibit dopamine (DA) reuptake through the dopamine transporter (DAT) represents a major public health issue, however FDA-approved pharmacotherapies have yet to be developed. Recently a class of ligands termed "atypical DAT inhibitors" has gained attention due to their range of effectiveness in increasing extracellular DA levels without demonstrating significant abuse liability. These compounds not only hold promise as therapeutic agents to treat stimulant use disorders but also as experimental tools to improve our understanding of DAT function. Here we used patch clamp electrophysiology in mouse brain slices to explore the effects of two atypical DAT inhibitors (R-modafinil and JHW 007) on the physiology of single DA neurons in the substantia nigra and ventral tegmental area. Despite their commonalities of being DAT inhibitors that lack cocaine-like behavioral profiles, these compounds exhibited surprisingly divergent cellular effects. Similar to cocaine, R-modafinil slowed DA neuron firing in a D2 receptor-dependent manner and rapidly enhanced the amplitude and duration of D2 receptor-mediated currents in the midbrain. In contrast, JHW 007 exhibited little effect on firing, slow DAT blockade, and an unexpected inhibition of D2 receptor-mediated currents that may be due to direct D2 receptor antagonism. Furthermore, pretreatment with JHW 007 blunted the cellular effects of cocaine, suggesting that it may be valuable to investigate similar DAT inhibitors as potential therapeutic agents. Further exploration of these and other atypical DAT inhibitors may reveal important cellular effects of compounds that will have potential as pharmacotherapies for treating cocaine use disorders.
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Affiliation(s)
- Alicia J Avelar
- Department of Cellular and Integrative Physiology, UT Health Science Center, San Antonio, TX, 78229, USA.
| | - Jianjing Cao
- Medicinal Chemistry Section, Molecular Targets and Medications Discovery Branch, National Institute on Drug Abuse, Intramural Research Program, National Institutes of Health, Baltimore, MD, 21224, USA.
| | - Amy Hauck Newman
- Medicinal Chemistry Section, Molecular Targets and Medications Discovery Branch, National Institute on Drug Abuse, Intramural Research Program, National Institutes of Health, Baltimore, MD, 21224, USA.
| | - Michael J Beckstead
- Department of Cellular and Integrative Physiology, UT Health Science Center, San Antonio, TX, 78229, USA.
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McCall NM, Kotecki L, Dominguez-Lopez S, Marron Fernandez de Velasco E, Carlblom N, Sharpe AL, Beckstead MJ, Wickman K. Selective Ablation of GIRK Channels in Dopamine Neurons Alters Behavioral Effects of Cocaine in Mice. Neuropsychopharmacology 2017; 42:707-715. [PMID: 27468917 PMCID: PMC5240170 DOI: 10.1038/npp.2016.138] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/16/2016] [Revised: 07/23/2016] [Accepted: 07/25/2016] [Indexed: 12/20/2022]
Abstract
The increase in dopamine (DA) neurotransmission stimulated by in vivo cocaine exposure is tempered by G protein-dependent inhibitory feedback mechanisms in DA neurons of the ventral tegmental area (VTA). G protein-gated inwardly rectifying K+ (GIRK/Kir3) channels mediate the direct inhibitory effect of GABAB receptor (GABABR) and D2 DA receptor (D2R) activation in VTA DA neurons. Here we examined the effect of the DA neuron-specific loss of GIRK channels on D2R-dependent regulation of VTA DA neuron excitability and on cocaine-induced, reward-related behaviors. Selective ablation of Girk2 in DA neurons did not alter the baseline excitability of VTA DA neurons but significantly reduced the magnitude of D2R-dependent inhibitory somatodendritic currents and blunted the impact of D2R activation on spontaneous activity and neuronal excitability. Mice lacking GIRK channels in DA neurons exhibited increased locomotor activation in response to acute cocaine administration and an altered locomotor sensitization profile, as well as increased responding for and intake of cocaine in an intravenous self-administration test. These mice, however, showed unaltered cocaine-induced conditioned place preference. Collectively, our data suggest that feedback inhibition to VTA DA neurons, mediated by GIRK channel activation, tempers the locomotor stimulatory effect of cocaine while also modulating the reinforcing effect of cocaine in an operant-based self-administration task.
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Affiliation(s)
- Nora M McCall
- Graduate Program in Neuroscience, University of Minnesota, Minneapolis, MN, USA
| | - Lydia Kotecki
- Department of Pharmacology, University of Minnesota, Minneapolis, MN, USA
| | - Sergio Dominguez-Lopez
- Department of Physiology, The University of Texas Health Science Center at San Antonio, San Antonio, TX, USA
| | | | - Nicholas Carlblom
- Department of Pharmacology, University of Minnesota, Minneapolis, MN, USA
| | - Amanda L Sharpe
- Department of Physiology, The University of Texas Health Science Center at San Antonio, San Antonio, TX, USA,Feik School of Pharmacy, University of the Incarnate Word, San Antonio, TX, USA
| | - Michael J Beckstead
- Department of Physiology, The University of Texas Health Science Center at San Antonio, San Antonio, TX, USA
| | - Kevin Wickman
- Department of Pharmacology, University of Minnesota, Minneapolis, MN, USA,Department of Pharmacology, University of Minnesota, 6-120 Jackson Hall, 321 Church Street S.E., Minneapolis, MN 55455, USA, Tel: +1 612 624 5966, Fax: +1 612 625 8408, E-mail:
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31
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Paredes RM, Piccart E, Navaira E, Cruz D, Javors MA, Koek W, Beckstead MJ, Walss-Bass C. Physiological and behavioral effects of amphetamine in BACE1(-/-) mice. Genes Brain Behav 2015; 14:411-8. [PMID: 25912880 DOI: 10.1111/gbb.12222] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2014] [Revised: 04/17/2015] [Accepted: 04/23/2015] [Indexed: 01/01/2023]
Abstract
β-Site APP-cleaving Enzyme 1 (BACE1) is a protease that has been linked to schizophrenia, a severe mental illness that is potentially characterized by enhanced dopamine (DA) release in the striatum. Here, we used acute amphetamine administration to stimulate neuronal activity and investigated the neurophysiological and locomotor-activity response in BACE1-deficient (BACE1(-/-) ) mice. We measured locomotor activity at baseline and after treatment with amphetamine (3.2 and 10 mg/kg). While baseline locomotor activity did not vary between groups, BACE1(-/-) mice exhibited reduced sensitivity to the locomotor-enhancing effects of amphetamine. Using high-performance liquid chromatography (HPLC) to measure DA and DA metabolites in the striatum, we found no significant differences in BACE1(-/-) compared with wild-type mice. To determine if DA neuron excitability is altered in BACE1(-/-) mice, we performed patch-clamp electrophysiology in putative DA neurons from brain slices that contained the substantia nigra. Pacemaker firing rate was slightly increased in slices from BACE1(-/-) mice. We next measured G protein-coupled potassium currents produced by activation of D2 autoreceptors, which strongly inhibit firing of these neurons. The maximal amplitude and decay times of D2 autoreceptor currents were not altered in BACE1(-/-) mice, indicating no change in D2 autoreceptor-sensitivity and DA transporter-mediated reuptake. However, amphetamine (30 µm)-induced potassium currents produced by efflux of DA were enhanced in BACE1(-/-) mice, perhaps indicating increased vesicular DA content in the midbrain. This suggests a plausible mechanism to explain the decreased sensitivity to amphetamine-induced locomotion, and provides evidence that decreased availability of BACE1 can produce persistent adaptations in the dopaminergic system.
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Affiliation(s)
- R Madelaine Paredes
- Department of Psychiatry, University of Texas Health Science Center, San Antonio
| | - E Piccart
- Department of Psychiatry, University of Texas Health Science Center, San Antonio
| | - E Navaira
- Department of Psychiatry, University of Texas Health Science Center, San Antonio
| | - D Cruz
- Department of Psychiatry, University of Texas Health Science Center, San Antonio
| | - M A Javors
- Department of Psychiatry, University of Texas Health Science Center, San Antonio
| | - W Koek
- Department of Psychiatry, University of Texas Health Science Center, San Antonio
| | - M J Beckstead
- Department of Psychiatry, University of Texas Health Science Center, San Antonio
| | - C Walss-Bass
- Department of Psychiatry and Behavioral Sciences, University of Texas Health Science Center at Houston, Houston, TX, USA
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Abstract
BACKGROUND Methamphetamine is a psychomotor stimulant with abuse liability and a substrate for catecholamine uptake transporters. Acute methamphetamine elevates extracellular dopamine, which in the midbrain can activate D2 autoreceptors to increase a G-protein gated inwardly rectifying potassium (GIRK) conductance that inhibits dopamine neuron firing. These studies examined the neurophysiological consequences of methamphetamine self-administration on GIRK channel-mediated currents in dopaminergic neurons in the substantia nigra and ventral tegmental area. METHODS Male DBA/2J mice were trained to self-administer intravenous methamphetamine. A dose response was conducted as well as extinction and cue-induced reinstatement. In a second study, after at least 2 weeks of stable self-administration of methamphetamine, electrophysiological brain slice recordings were conducted on dopamine neurons from self-administering and control mice. RESULTS In the first experiment, ad libitum-fed, nonfood-trained mice exhibited a significant increase in intake and locomotion following self-administration as the concentration of methamphetamine per infusion was increased (0.0015-0.15mg/kg/infusion). Mice exhibited extinction in responding and cue-induced reinstatement. In the second experiment, dopamine cells in both the substantia nigra and ventral tegmental area from adult mice with a history of methamphetamine self-administration exhibited significantly smaller D2 and GABAB receptor-mediated currents compared with control mice, regardless of whether their daily self-administration sessions had been 1 or 4 hours. Interestingly, the effects of methamphetamine self-administration were not present when intracellular calcium was chelated by including BAPTA in the recording pipette. CONCLUSIONS Our results suggest that methamphetamine self-administration decreases GIRK channel-mediated currents in dopaminergic neurons and that this effect may be calcium dependent.
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Affiliation(s)
- Amanda L Sharpe
- Department of Pharmaceutical Sciences, Feik School of Pharmacy, University of the Incarnate Word, San Antonio, Texas (Dr Sharpe, L. Bettinger); Department of Physiology, University of Texas Health Science Center at San Antonio, San Antonio, Texas (Dr Sharpe, E. Varela, and Dr Beckstead); Center for Biomedical Neuroscience, University of Texas Health Science Center at San Antonio, San Antonio, Texas (Dr Beckstead)
| | - Erika Varela
- Department of Pharmaceutical Sciences, Feik School of Pharmacy, University of the Incarnate Word, San Antonio, Texas (Dr Sharpe, L. Bettinger); Department of Physiology, University of Texas Health Science Center at San Antonio, San Antonio, Texas (Dr Sharpe, E. Varela, and Dr Beckstead); Center for Biomedical Neuroscience, University of Texas Health Science Center at San Antonio, San Antonio, Texas (Dr Beckstead)
| | - Lynne Bettinger
- Department of Pharmaceutical Sciences, Feik School of Pharmacy, University of the Incarnate Word, San Antonio, Texas (Dr Sharpe, L. Bettinger); Department of Physiology, University of Texas Health Science Center at San Antonio, San Antonio, Texas (Dr Sharpe, E. Varela, and Dr Beckstead); Center for Biomedical Neuroscience, University of Texas Health Science Center at San Antonio, San Antonio, Texas (Dr Beckstead)
| | - Michael J Beckstead
- Department of Pharmaceutical Sciences, Feik School of Pharmacy, University of the Incarnate Word, San Antonio, Texas (Dr Sharpe, L. Bettinger); Department of Physiology, University of Texas Health Science Center at San Antonio, San Antonio, Texas (Dr Sharpe, E. Varela, and Dr Beckstead); Center for Biomedical Neuroscience, University of Texas Health Science Center at San Antonio, San Antonio, Texas (Dr Beckstead).
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Branch SY, Beckstead MJ. Methamphetamine produces bidirectional, concentration-dependent effects on dopamine neuron excitability and dopamine-mediated synaptic currents. J Neurophysiol 2012; 108:802-9. [PMID: 22592307 DOI: 10.1152/jn.00094.2012] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Amphetamine-like compounds are commonly used to enhance cognition and to treat attention deficit/hyperactivity disorder, but they also function as positive reinforcers and are self-administered at doses far exceeding clinical relevance. Many of these compounds (including methamphetamine) are substrates for dopamine reuptake transporters, elevating extracellular dopamine by inhibiting uptake and promoting reverse transport. This produces an increase in extracellular dopamine that inhibits dopamine neuron firing through autoreceptor activation and consequently blunts phasic dopamine neurotransmission, an important learning signal. However, these mechanisms do not explain the beneficial behavioral effects observed at clinically useful concentrations. In the present study, we have used patch-clamp electrophysiology in slices of mouse midbrain to show that, surprisingly, low concentrations of methamphetamine actually enhance dopamine neurotransmission and increase dopamine neuron firing through a dopamine transporter-mediated excitatory conductance. Both of these effects are reversed by higher concentrations of methamphetamine, which inhibit firing through dopamine D2 autoreceptor activation and decrease the peak amplitude of dopamine-mediated synaptic currents. These competing, concentration-dependent effects of methamphetamine suggest a mechanistic interplay by which lower concentrations of methamphetamine can overcome autoreceptor-mediated inhibition at the soma to increase phasic dopamine transmission.
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Affiliation(s)
- Sarah Y Branch
- Department of Physiology, University of Texas Health Science Center, San Antonio, Texas 78229, USA
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Beckstead MJ, Gantz SC, Ford CP, Stenzel-Poore MP, Phillips PEM, Mark GP, Williams JT. CRF enhancement of GIRK channel-mediated transmission in dopamine neurons. Neuropsychopharmacology 2009; 34:1926-35. [PMID: 19279570 PMCID: PMC3640552 DOI: 10.1038/npp.2009.25] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Dopamine neurons in the ventral midbrain contribute to learning and memory of natural and drug-related rewards. Corticotropin-releasing factor (CRF), a stress-related peptide, is thought to be involved in aspects of relapse following drug withdrawal, but the cellular actions are poorly understood. This study investigates the action of CRF on G-protein-linked inhibitory postsynaptic currents (IPSCs) mediated by GIRK (Kir3) channels in dopamine neurons. CRF enhanced the amplitude and slowed the kinetics of IPSCs following activation of D2-dopamine and GABA(B) receptors. This action was postsynaptic and dependent on the CRF(1) receptor. The enhancement induced by CRF was attenuated by repeated in vivo exposures to psychostimulants or restraint stress. The results indicate that CRF influences dopamine- and GABA-mediated inhibition in the midbrain, suggesting implications for the chronic actions of psychostimulants and stress on dopamine-mediated behaviors.
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Affiliation(s)
- Michael J Beckstead
- Department of Behavioral Neuroscience, Oregon Health and Science University, Portland, OR, USA;
,Vollum Institute, Oregon Health and Science University, Portland, OR, USA;
| | - Stephanie C Gantz
- Vollum Institute, Oregon Health and Science University, Portland, OR, USA;
| | - Christopher P Ford
- Vollum Institute, Oregon Health and Science University, Portland, OR, USA;
| | - Mary P Stenzel-Poore
- Department of Molecular Microbiology and Immunology, Oregon Health and Science University, Portland, OR, USA;
| | - Paul EM Phillips
- Department of Psychiatry and Behavioral Sciences, University of Washington, Seattle, WA, USA;
,Department of Pharmacology, University of Washington, Seattle, WA, USA
| | - Gregory P Mark
- Department of Behavioral Neuroscience, Oregon Health and Science University, Portland, OR, USA;
| | - John T Williams
- Vollum Institute, Oregon Health and Science University, Portland, OR, USA;
,
Correspondence: Vollum Institute, L474, Oregon Health and Science University, 3181 SW Sam Jackson Park Road, Portland, OR 97239, USA, Tel: + 503 494 5465, Fax + 503 494 6972,
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35
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Beckstead MJ, Phillips TJ. Mice selectively bred for high- or low-alcohol-induced locomotion exhibit differences in dopamine neuron function. J Pharmacol Exp Ther 2009; 329:342-9. [PMID: 19122113 DOI: 10.1124/jpet.108.146316] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Elevated sensitivity to the euphoric or stimulant effects of ethanol is associated with higher levels of alcohol use in some human populations. Midbrain dopamine neurons are thought to be important mediators of both ethanol reward and locomotor stimulation. Patch-clamp recordings were used to examine the electrical properties of dopamine neurons in a genetic model of heightened (FAST) and reduced (SLOW) sensitivity to the locomotor-activating effects of ethanol. Pacemaker firing of dopamine neurons was faster in FAST than SLOW mice, as was the current density through I(H) channels. Acute administration of ethanol accelerated the firing of dopamine neurons to a greater extent in recordings from FAST than SLOW mice. Dopamine neurons from FAST mice also exhibited reduced GABA(A) receptor-mediated synaptic input, compared with SLOW mice. The results suggest that dopamine neuron I(H) channels, firing rate, and GABAergic input may play a role in sensitivity to the locomotor activation observed at early time points after ethanol administration and could underlie differences in sensitivity to alcohol relevant to risk for alcohol abuse.
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Affiliation(s)
- Michael J Beckstead
- Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, Oregon, USA.
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Abstract
The amount of dopamine release from terminals in the forebrain following an electrical stimulus is variable. This dynamic regulation, both between and within trains of electrical stimuli, has fostered the notion that burst firing of dopamine neurons in vivo may be a determinant of dopamine release in projection areas. In the present study dendritic dopamine release was examined in the substantia nigra and ventral tegmental area in mouse brain slices using whole-cell recording of a dopamine-mediated inhibitory postsynaptic current (IPSC). Paired stimuli produced a depression of the IPSC that was not observed with paired pulses of exogenously applied dopamine. Increasing the number of electrical stimuli from one to five produced an increase in the amplitude the dopamine IPSC but the increase was less than additive, indicating a depression of transmission with each successive stimulus. Analysis with fast-scan cyclic voltammetry demonstrated that presynaptic D2-autoreceptors did not contribute to the depression. Facilitation of the IPSC was observed only after the probability of release was reduced. Thus the regulation of dopamine release in the cell body region was dependent on dopamine neuron impulse activity. Under circumstance where there was initially little activity the probability of dopamine release was high and repetitive activation resulted in depression of further release. With increased activity, the release probability decreased and a burst of activity caused a relative facilitation of dopamine release. This form of regulation would be expected to limit activity within the cell body region.
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Affiliation(s)
- Michael J. Beckstead
- Vollum Institute, L474, Oregon Health & Science University, 3181 SW Sam Jackson Park Road., Portland, OR, USA
| | - Christopher P. Ford
- Vollum Institute, L474, Oregon Health & Science University, 3181 SW Sam Jackson Park Road., Portland, OR, USA
| | - Paul E. M. Phillips
- Department of Psychiatry and Behavioural Sciences and Department of Pharmacology, University of Washington, Seattle, WA 98195, USA
| | - John T. Williams
- Vollum Institute, L474, Oregon Health & Science University, 3181 SW Sam Jackson Park Road., Portland, OR, USA
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Abstract
Two determinants of dopamine release from terminals in striatal and limbic structures are the pattern and rate of dopamine neuron firing in the ventral midbrain. This activity is regulated in part by somatodendritic release of dopamine and subsequent feedback inhibition through activation of D2 receptors on dopamine neuron cell bodies and dendrites. This study describes stimulus-dependent long-term depression (LTD) of IPSCs mediated by dopamine. This LTD was blocked by chelation of postsynaptic intracellular calcium, was dependent on the activation of D2 receptors and was independent of glutamate-mediated transmission. Application of a high concentration of dopamine mimicked depression of the IPSC and prevented additional attempts to induce LTD, suggesting that the mechanism of the depression is agonist-dependent receptor activation. Using extracellular recording, there is an inhibition of firing that follows electrical stimulation, and after the induction of LTD the duration of that inhibition was decreased. Reduced inhibition could increase burst firing and action potential-dependent release of dopamine in terminal regions in vivo.
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Affiliation(s)
| | - John T. Williams
- Vollum Institute, Oregon Health and Science University, Portland, Oregon, 97239
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Paladini CA, Beckstead MJ, Weinshenker D. Electrophysiological properties of catecholaminergic neurons in the norepinephrine-deficient mouse. Neuroscience 2006; 144:1067-74. [PMID: 17156935 PMCID: PMC1847415 DOI: 10.1016/j.neuroscience.2006.10.032] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2006] [Revised: 10/03/2006] [Accepted: 10/14/2006] [Indexed: 11/22/2022]
Abstract
To determine how norepinephrine affects the basic physiological properties of catecholaminergic neurons, brain slices containing the substantia nigra pars compacta and locus coeruleus were studied with cell-attached and whole-cell recordings in control and dopamine beta-hydroxylase knockout (Dbh -/-) mice that lack norepinephrine. In the cell-attached configuration, the spontaneous firing rate and pattern of locus coeruleus neurons recorded from Dbh -/- mice were the same as the firing rate and pattern recorded from heterozygous littermates (Dbh +/-). During whole-cell recordings, synaptic stimulation produced an alpha-2 receptor-mediated outward current in the locus coeruleus of control mice that was absent in Dbh -/- mice. Normal alpha-2 mediated outward currents were restored in Dbh -/- slices after pre-incubation with norepinephrine. Locus coeruleus neurons also displayed similar changes in holding current in response to bath application of norepinephrine, UK 14304, and methionine-enkephalin. Dopamine neurons recorded in the substantia nigra pars compacta similarly showed no differences between slices harvested from Dbh -/- and control mice. These results indicate that endogenous norepinephrine is not necessary for the expression of catecholaminergic neuron firing properties or responses to direct agonists, but is necessary for auto-inhibition mediated by indirect alpha-2 receptor stimulation.
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Affiliation(s)
- C A Paladini
- Biology Department, University of Texas at San Antonio, One UTSA Circle, San Antonio, TX 78249, USA.
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Abstract
In the midbrain, dopamine neurons can release dopamine somatodendritically. This results in an inhibitory postsynaptic current (IPSC) within adjacent dopamine cells that occurs by the activation of inhibitory D(2) autoreceptors. Kappa, but not mu/delta, opioid receptors inhibit this IPSC. The aim of the present study was to determine the mechanism by which kappa-opioid receptors inhibit the dopamine IPSC. In both the ventral tegmental area (VTA) and substantia nigra compacta (SNc) the kappa-receptor agonist U69593 inhibited the IPSC, but not the current induced by the exogenous iontophoretic application of dopamine. The endogenous peptide dynorphin A (1-13) also inhibited IPSCs in the VTA and SNc, but also the dopamine iontophoretic current in the VTA. Although both kappa agonists induced a postsynaptic outward current in the VTA, the current induced by dynorphin was dramatically larger. This suggests that the decrease in iontophoretic dopamine current was the result of occlusion. Occlusion alone, however, could not completely account for suppression of the IPSC. The kappa opioid inhibition of the IPSC was not affected by global increases or decreases in dopamine cell activity within the slice. These findings suggest that, although kappa opioid receptors can hyperpolarize dopamine neurons, they also suppress dopamine release by direct actions at the release site. The results thus demonstrate both pre- and postsynaptic actions of kappa receptor agonists. The actions of dynorphin indicate that VTA dopamine cells are selectively regulated by kappa receptors.
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Affiliation(s)
- Christopher P Ford
- Vollum Institute, Oregon Health and Science University, 3181 SW Sam Jackson Park Road, Portland, OR 97239, USA
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40
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Beckstead MJ, Grandy DK, Wickman K, Williams JT. Vesicular dopamine release elicits an inhibitory postsynaptic current in midbrain dopamine neurons. Neuron 2004; 42:939-46. [PMID: 15207238 DOI: 10.1016/j.neuron.2004.05.019] [Citation(s) in RCA: 226] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2004] [Revised: 04/23/2004] [Accepted: 05/18/2004] [Indexed: 10/26/2022]
Abstract
Synchronous activation of dopamine neurons, for instance upon presentation of an unexpected rewarding stimulus, results in the release of dopamine from both terminals in projection areas and somatodendritic sites within the ventral midbrain. This report describes an inhibitory postsynaptic current (IPSC) that was elicited by dopamine in slices from mouse midbrain. The IPSC was tetrodotoxin sensitive, calcium dependent, and blocked by a D2 receptor antagonist. Inhibition of monoamine transporters prolonged the IPSC, indicating that the time course of dopamine neurotransmission is tightly regulated by reuptake. Changing the stimulus intensity altered the amplitude but not the time course of the IPSC, whose onset was faster than could be reproduced with iontophoresis. The results indicate a rapid rise in dopamine concentration at the D2 receptors, suggesting that dopamine that is released by a train of action potentials acts in a localized area rather than in a manner consistent with volume transmission.
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Affiliation(s)
- Michael J Beckstead
- Vollum Institute, Oregon Health and Science University, Portland, OR 97239, USA
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Abstract
Despite the prevalence of their use, little is currently known of the molecular mechanisms of action of inhaled drugs of abuse. Recent studies have shown effects on NMDA, GABA(A) and glycine receptors in vitro, suggesting that inhalants may exert at least some of their pharmacological effects on ligand-gated ion channels. Enhancement of serotonin-3 receptor function has been shown to play a role in the reinforcing properties of drugs of abuse. We tested the hypothesis that the commonly abused inhaled agents 1,1,1-trichloroethane, trichloroethylene, and toluene enhance serotonin-3 receptor function. All three inhalants significantly and reversibly potentiated, in a dose-dependent manner, serotonin-activated currents mediated by mouse serotonin-3A receptors expressed in Xenopus oocytes. Our findings add the serotonin-3 receptor to the growing list of molecular targets commonly affected by both inhalants and classic CNS depressants such as ethanol and the volatile anesthetics.
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Affiliation(s)
- Gregory F Lopreato
- Section of Neurobiology, Waggoner Center for Alcohol & Addiction Research, Institute for Neuroscience, and the Institute for Cellular & Molecular Biology, University of Texas at Austin, Austin, TX 78712-0159, USA.
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Abstract
Strychnine-sensitive glycine receptors mediate inhibitory neurotransmission occurring in the brain stem and spinal cord. Alcohols, volatile anesthetics and inhaled drugs of abuse are positive allosteric modulators of glycine receptor function, normally enhancing function only in the presence of glycine. A complication in studying allosteric actions on ligand-gated ion channels is in the dissection of their effects on neurotransmitter binding from their effects on channel opening. Mutation of an aspartate residue at position 97 to arginine in the glycine receptor alpha1 subunit simulated the effects of glycine binding, producing receptors that exhibited tonic channel opening in the absence of neurotransmitter; i.e. these receptors demonstrated a dissociation of channel opening from neurotransmitter binding. In these receptors, ethanol, enflurane, chloroform, halothane, 1,1,1-trichloroethane and toluene elicited inward currents in the absence of glycine. We previously identified mutations on ligand-gated ion channels that eliminate ethanol, anesthetic and inhalant actions (such as S267I on alpha1 glycine receptors). The double mutant (D97R and S267I) receptors were both constitutively active and resistant to the enhancing effects of ethanol and enflurane. These data demonstrate that ethanol and volatile anesthetics can affect glycine receptor channel opening independently of their effects on enhancing neurotransmitter binding.
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Affiliation(s)
- Michael J Beckstead
- Department of Physiology and Pharmacology, Wake Forest University School of Medicine, Winston-Salem, North Carolina, USA
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Mascia MP, Maiya R, Borghese CM, Lobo IA, Hara K, Yamakura T, Gong DH, Beckstead MJ. Does Acetaldehyde Mediate Ethanol Action in the Central Nervous System? Alcohol Clin Exp Res 2001. [DOI: 10.1111/j.1530-0277.2001.tb02163.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Mascia MP, Maiya R, Borghese CM, Lobo IA, Hara K, Yamakura T, Gong DH, Beckstead MJ. Does acetaldehyde mediate ethanol action in the central nervous system? Alcohol Clin Exp Res 2001; 25:1570-5. [PMID: 11707631] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/22/2023]
Abstract
BACKGROUND Some of the effects of ethanol in the central nervous system are due to changes in function of ligand-gated ion channels. Production of detectable amounts of acetaldehyde, a primary metabolite of ethanol, has been demonstrated in brain homogenates. The aim of this study was to determine whether central actions that are often attributed to ethanol may actually be mediated by acetaldehyde. METHODS The effects of acetaldehyde (1-1000 microM) were tested by two-electrode voltage-clamp electrophysiology in Xenopus laevis oocytes expressing 10 different ligand-gated ion channel receptors [alpha1 glycine; alpha1beta2gamma2Sgamma-aminobutyric acid (GABA)A; rho1 GABAc; 5-hydroxytryptamine-3A; NR1a/NR2A NMDA; GluR1/GluR2 AMPA; GluR6/KA2 kainate; and alpha4beta2, alpha4beta4, and alpha2beta4 nicotinic-acetylcholine] and the G-protein-coupled inward rectifying potassium channel GIRK2. We also investigated the effect of acetaldehyde on the dopamine transporter (DAT), performing dopamine uptake assays in oocytes expressing DAT. RESULTS Acetaldehyde (1 and 10 microM) significantly enhanced alpha1 glycine receptor-mediated currents. Acetaldehyde did not affect the function of any of the other receptors tested or the potassium currents measured in GIRK2 channels. Moreover, acetaldehyde did not alter the DAT-mediated dopamine uptake. CONCLUSIONS Our results suggest a potential minor role for acetaldehyde in the glycine receptor-mediated effects of ethanol. Otherwise, acetaldehyde does not modulate function of the neuronal receptors tested in this study, in GIRK channels or DAT, when expressed recombinantly in Xenopus laevis oocytes.
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MESH Headings
- Acetaldehyde/pharmacology
- Animals
- Central Nervous System/drug effects
- Dopamine Plasma Membrane Transport Proteins
- Drug Interactions
- Electric Conductivity
- Ethanol/pharmacology
- Female
- G Protein-Coupled Inwardly-Rectifying Potassium Channels
- Gene Expression
- Humans
- Membrane Glycoproteins
- Membrane Transport Proteins/drug effects
- Membrane Transport Proteins/genetics
- Membrane Transport Proteins/physiology
- Nerve Tissue Proteins
- Oocytes/metabolism
- Patch-Clamp Techniques
- Potassium Channels/drug effects
- Potassium Channels/genetics
- Potassium Channels/physiology
- Potassium Channels, Inwardly Rectifying
- Receptors, Cholinergic/drug effects
- Receptors, Cholinergic/genetics
- Receptors, Cholinergic/physiology
- Receptors, GABA/drug effects
- Receptors, GABA/genetics
- Receptors, GABA/physiology
- Receptors, Glutamate/drug effects
- Receptors, Glutamate/genetics
- Receptors, Glutamate/physiology
- Receptors, Glycine/drug effects
- Receptors, Glycine/genetics
- Receptors, Glycine/physiology
- Receptors, Kainic Acid/drug effects
- Receptors, Kainic Acid/genetics
- Receptors, Kainic Acid/physiology
- Receptors, N-Methyl-D-Aspartate/drug effects
- Receptors, N-Methyl-D-Aspartate/genetics
- Receptors, N-Methyl-D-Aspartate/physiology
- Receptors, Nicotinic/drug effects
- Receptors, Nicotinic/genetics
- Receptors, Nicotinic/physiology
- Receptors, Serotonin/drug effects
- Receptors, Serotonin/genetics
- Receptors, Serotonin/physiology
- Recombinant Proteins
- Xenopus laevis
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Affiliation(s)
- M P Mascia
- Consiglio Nazionale delle Ricerche, Department of Experimental Biology, Center of Neuropharmacology, University of Cagliari, Cagliari, Italy
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Abstract
Recent studies suggest that alcohols, volatile anesthetics, and inhaled drugs of abuse, which enhance gamma-aminobutyric acid, type A, and glycine receptor-activated ion channel function, may share common or overlapping molecular sites of action on these receptors. To investigate this possibility, these compounds were applied singly and in combination to wild-type glycine alpha(1) receptors expressed in Xenopus laevis oocytes. Data obtained from concentration-response curves of the volatile anesthetic enflurane constructed in the presence and absence of ethanol, chloroform, or toluene were consistent with competition for a common binding pocket on these receptors. A mutant glycine receptor, insensitive to the enhancing effects of ethanol but not anesthetics or inhalants, demonstrated antagonism of anesthetic and inhalant effects on this receptor. Although ethanol (25-200 mm) had no effect on its own in this receptor, it was able to inhibit reversibly the enhancing effect of enflurane, toluene, and chloroform in a concentration-dependent manner. These data suggest the existence of overlapping molecular sites of action for ethanol, inhalants, and volatile anesthetics on glycine receptors and illustrate the feasibility of pharmacological antagonism of the effects of volatile anesthetics.
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Affiliation(s)
- M J Beckstead
- Department of Physiology and Pharmacology, Wake Forest University School of Medicine, Winston-Salem, NC 27157, USA.
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Beckstead MJ, Weiner JL, Eger EI, Gong DH, Mihic SJ. Glycine and gamma-aminobutyric acid(A) receptor function is enhanced by inhaled drugs of abuse. Mol Pharmacol 2000; 57:1199-205. [PMID: 10825391] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/16/2023] Open
Abstract
Inhalable solvents possess significant abuse liability and produce many of the neurobehavioral effects typically associated with central nervous system-depressant agents, including motor incoordination, anxiolysis, and the elicitation of signs of physical dependence on withdrawal. We tested the hypothesis that the commonly abused solvents toluene, 1,1,1-trichloroethane (TCE), and trichloroethylene (TCY) affect ligand-gated ion channel activity, as do other classes of central nervous system-depressive agents. TCE and toluene, like ethanol, reversibly enhanced gamma-aminobutyric acid (GABA)(A) receptor-mediated synaptic currents in rat hippocampal slices. All three inhalants significantly and reversibly enhanced neurotransmitter-activated currents at alpha1beta1 GABA(A) and alpha1 glycine receptors expressed in Xenopus oocytes. We previously identified specific amino acids of glycine and GABA(A) receptor subunits mediating alcohol and volatile anesthetic enhancement of receptor function. Toluene, TCE, and TCY were tested on several glycine receptor mutants, some of which were insensitive to ethanol and/or enflurane. Toluene and TCY enhancement of glycine receptor function was seen in all these mutants. However, the potentiating effects of TCE were abolished in three mutants and enhanced in two, a pattern more akin to that seen with enflurane than ethanol. These data suggest that inhaled drugs of abuse affect ligand-gated ion channels, and that the molecular sites of action of these compounds may overlap with those of ethanol and the volatile anesthetics.
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Affiliation(s)
- M J Beckstead
- Department of Physiology and Pharmacology, Wake Forest University School of Medicine, Winston-Salem, NC, USA
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