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Tjahjono N, Jin Y, Hsu A, Roukes M, Tian L. Letting the little light of mind shine: Advances and future directions in neurochemical detection. Neurosci Res 2022; 179:65-78. [PMID: 34861294 PMCID: PMC9508992 DOI: 10.1016/j.neures.2021.11.012] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [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: 11/28/2021] [Accepted: 11/29/2021] [Indexed: 12/12/2022]
Abstract
Synaptic transmission via neurochemical release is the fundamental process that integrates and relays encoded information in the brain to regulate physiological function, cognition, and emotion. To unravel the biochemical, biophysical, and computational mechanisms of signal processing, one needs to precisely measure the neurochemical release dynamics with molecular and cell-type specificity and high resolution. Here we reviewed the development of analytical, electrochemical, and fluorescence imaging approaches to detect neurotransmitter and neuromodulator release. We discussed the advantages and practicality in implementation of each technology for ease-of-use, flexibility for multimodal studies, and challenges for future optimization. We hope this review will provide a versatile guide for tool engineering and applications for recording neurochemical release.
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Affiliation(s)
- Nikki Tjahjono
- Biomedical Engineering Graduate Group, University of California, Davis, Davis, CA, 95616, USA
| | - Yihan Jin
- Neuroscience Graduate Group, University of California, Davis, Davis, CA, 95618, USA
| | - Alice Hsu
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, 91125, USA
| | - Michael Roukes
- Department of Physics, California Institute of Technology, Pasadena, CA, 91125, USA
| | - Lin Tian
- Department of Biochemistry and Molecular Medicine, School of Medicine, University of California, Davis, Davis, CA, 95616, USA.
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2
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McLaurin KA, Harris M, Madormo V, Harrod SB, Mactutus CF, Booze RM. HIV-Associated Apathy/Depression and Neurocognitive Impairments Reflect Persistent Dopamine Deficits. Cells 2021; 10:2158. [PMID: 34440928 PMCID: PMC8392364 DOI: 10.3390/cells10082158] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [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: 07/06/2021] [Revised: 08/10/2021] [Accepted: 08/18/2021] [Indexed: 12/12/2022] Open
Abstract
Individuals living with human immunodeficiency virus type 1 (HIV-1) are often plagued by debilitating neurocognitive impairments and affective alterations;the pathophysiology underlying these deficits likely includes dopaminergic system dysfunction. The present review utilized four interrelated aims to critically examine the evidence for dopaminergic alterations following HIV-1 viral protein exposure. First, basal dopamine (DA) values are dependent upon both brain region andexperimental approach (i.e., high-performance liquid chromatography, microdialysis or fast-scan cyclic voltammetry). Second, neurochemical measurements overwhelmingly support decreased DA concentrations following chronic HIV-1 viral protein exposure. Neurocognitive impairments, including alterations in pre-attentive processes and attention, as well as apathetic behaviors, provide an additional line of evidence for dopaminergic deficits in HIV-1. Third, to date, there is no compelling evidence that combination antiretroviral therapy (cART), the primary treatment regimen for HIV-1 seropositive individuals, has any direct pharmacological action on the dopaminergic system. Fourth, the infection of microglia by HIV-1 viral proteins may mechanistically underlie the dopamine deficit observed following chronic HIV-1 viral protein exposure. An inclusive and critical evaluation of the literature, therefore, supports the fundamental conclusion that long-term HIV-1 viral protein exposure leads to a decreased dopaminergic state, which continues to persist despite the advent of cART. Thus, effective treatment of HIV-1-associated apathy/depression and neurocognitive impairments must focus on strategies for rectifying decreases in dopamine function.
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Affiliation(s)
| | | | | | | | | | - Rosemarie M. Booze
- Department of Psychology, University of South Carolina, Columbia, SC 29208, USA; (K.A.M.); (M.H.); (V.M.); (S.B.H.); (C.F.M.)
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3
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Rusheen AE, Gee TA, Jang DP, Blaha CD, Bennet KE, Lee KH, Heien ML, Oh Y. Evaluation of electrochemical methods for tonic dopamine detection in vivo. Trends Analyt Chem 2020; 132:116049. [PMID: 33597790 PMCID: PMC7885180 DOI: 10.1016/j.trac.2020.116049] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Dysfunction in dopaminergic neuronal systems underlie a number of neurologic and psychiatric disorders such as Parkinson's disease, drug addiction, and schizophrenia. Dopamine systems communicate via two mechanisms, a fast "phasic" release (sub-second to second) that is related to salient stimuli and a slower "tonic" release (minutes to hours) that regulates receptor tone. Alterations in tonic levels are thought to be more critically important in enabling normal motor, cognitive, and motivational functions, and dysregulation in tonic dopamine levels are associated with neuropsychiatric disorders. Therefore, development of neurochemical recording techniques that enable rapid, selective, and quantitative measurements of changes in tonic extracellular levels are essential in determining the role of dopamine in both normal and disease states. Here, we review state-of-the-art advanced analytical techniques for in vivo detection of tonic levels, with special focus on electrochemical techniques for detection in humans.
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Affiliation(s)
- Aaron E. Rusheen
- Department of Neurologic Surgery, Mayo Clinic, Rochester, MN, 55905, United States
- Medical Scientist Training Program, Mayo Clinic, Rochester, MN, 55905, United States
| | - Taylor A. Gee
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ, 85721, United States
| | - Dong P. Jang
- Department of Biomedical Engineering, Hanyang University, Seoul, 04763, Republic of Korea
| | - Charles D. Blaha
- Department of Neurologic Surgery, Mayo Clinic, Rochester, MN, 55905, United States
| | - Kevin E. Bennet
- Department of Neurologic Surgery, Mayo Clinic, Rochester, MN, 55905, United States
- Division of Engineering, Mayo Clinic, Rochester, MN, 55905, United States
| | - Kendall H. Lee
- Department of Neurologic Surgery, Mayo Clinic, Rochester, MN, 55905, United States
- Department of Biomedical Engineering, Mayo Clinic, Rochester, MN, 55905, United States
| | - Michael L. Heien
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ, 85721, United States
| | - Yoonbae Oh
- Department of Neurologic Surgery, Mayo Clinic, Rochester, MN, 55905, United States
- Department of Biomedical Engineering, Mayo Clinic, Rochester, MN, 55905, United States
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El-Sherbeni AA, Stocco MR, Wadji FB, Tyndale RF. Addressing the instability issue of dopamine during microdialysis: the determination of dopamine, serotonin, methamphetamine and its metabolites in rat brain. J Chromatogr A 2020; 1627:461403. [PMID: 32823108 PMCID: PMC7484461 DOI: 10.1016/j.chroma.2020.461403] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [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: 05/01/2020] [Revised: 07/10/2020] [Accepted: 07/12/2020] [Indexed: 12/27/2022]
Abstract
Dopamine is a catecholamine neurotransmitter that degrades rapidly in aqueous solutions; hence, its analysis following brain microdialysis is challenging. The aim of the current study was to develop and validate a new microdialysis coupled LC-MS/MS system with improved accuracy, precision, simplicity and turnaround time for dopamine, serotonin, methamphetamine, amphetamine, 4-hydroxymethamphetamine and 4-hydroxyamphetamine analysis in the brain. Dopamine degradation was studied with different stabilizing agents under different storage conditions. The modified microdialysis system was tested in vitro, and was optimized for best probe recovery, assessed by %gain. LC-MS/MS assay was developed and validated for the targeted compounds. Stabilizing agents (ascorbic acid, EDTA and acetic acid) as well as internal and cold standards were added on-line to the dialysate flow. Assay linearity range was 0.01-100 ng/mL, precision and accuracy passed criteria, and LOQ and LLOQ were 0.2 and 1.0 pg, respectively. The new microdialysis coupled LC-MS/MS system was used in Wistar rats striatum after 4 mg/kg subcutaneous methamphetamine. Methamphetamine rapidly distributed to rat striatum reaching an average ~200 ng/mL maximum, ~82.5 min post-dose. Amphetamine, followed by 4-hydroxymethamphetamine, was the most abundant metabolite. Dopamine was released following methamphetamine injection, while serotonin was not altered. In conclusion, we proposed and tested an innovative and simplified solution to improve stability, accuracy and turnover time to monitor unstable molecules, such as dopamine, by microdialysis.
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Affiliation(s)
- Ahmed A El-Sherbeni
- Department of Pharmacology and Toxicology, University of Toronto, Toronto, Ontario, Canada; Department of Clinical Pharmacy, Faculty of Pharmacy, Tanta University, Tanta, Egypt
| | - Marlaina R Stocco
- Department of Pharmacology and Toxicology, University of Toronto, Toronto, Ontario, Canada
| | - Fariba Baghai Wadji
- Department of Pharmacology and Toxicology, University of Toronto, Toronto, Ontario, Canada
| | - Rachel F Tyndale
- Department of Pharmacology and Toxicology, University of Toronto, Toronto, Ontario, Canada; Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, Ontario, Canada; Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada.
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5
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Taylor IM, Patel NA, Freedman NC, Castagnola E, Cui XT. Direct in Vivo Electrochemical Detection of Resting Dopamine Using Poly(3,4-ethylenedioxythiophene)/Carbon Nanotube Functionalized Microelectrodes. Anal Chem 2019; 91:12917-12927. [PMID: 31512849 DOI: 10.1021/acs.analchem.9b02904] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Dopamine (DA) is a monoamine neurotransmitter responsible for the maintenance of a variety of vital life functions. In vivo DA signaling occurs over multiple time scales, from subsecond phasic release due to dopamine neuron firing to tonic release responsible for long-term DA concentration changes over minutes to hours. Due to the complex, multifaceted nature of DA signaling, analytical sensing technology must be capable of recording DA from multiple locations and over multiple time scales. Decades of research has focused on improving in vivo detection capabilities for subsecond phasic DA, but the accurate detection of absolute resting DA levels in real time has proven challenging. We have developed a poly(3,4-ethylenedioxythiophene) (PEDOT)-based nanocomposite coating that exhibits excellent DA sensing capabilities for resting DA. PEDOT/functionalized carbon nanotube (PEDOT/CNT)-coated carbon fiber microelectrodes (CFEs) are capable of directly measuring resting DA using square wave voltammetry (SWV) with high sensitivity and selectivity. Incorporation of a PEDOT/CNT coating significantly increases the sensitivity for the detection of resting DA by a factor of 422. SWV measurements performed at PEDOT/CNT-functionalized CFEs implanted in the rat dorsal striatum reveal the absolute basal DA concentration to be 82 ± 6 nM. Systemic administration of the dopamine transporter inhibitor nomifensine increases resting DA to a maximum 207 ± 16 nM at 28 ± 2 min following injection. PEDOT/CNT was also functionalized onto individual gold electrode sites along silicon microelectrode arrays (MEAs) to produce a multisite DA sensing electrode. MEA implantation allows for the quantification of basal DA from different brain regions with excellent spatial resolution. SWV detection paired with PEDOT/CNT functionalization is highly adaptable and shows great promise for tonic DA detection with high spatial and temporal resolution.
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Affiliation(s)
- Ian Mitchell Taylor
- Department of Bioengineering , University of Pittsburgh , Pittsburgh , Pennsylvania 15261 , United States.,Department of Chemistry , Saint Vincent College , Latrobe , Pennsylvania 15650 , United States
| | - Nikita Anurag Patel
- Department of Bioengineering , University of Pittsburgh , Pittsburgh , Pennsylvania 15261 , United States
| | - Noah Chaim Freedman
- Department of Bioengineering , University of Pittsburgh , Pittsburgh , Pennsylvania 15261 , United States
| | - Elisa Castagnola
- Department of Bioengineering , University of Pittsburgh , Pittsburgh , Pennsylvania 15261 , United States
| | - Xinyan Tracy Cui
- Department of Bioengineering , University of Pittsburgh , Pittsburgh , Pennsylvania 15261 , United States
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Felmer AC, Janson MT, Summers KE, Wallace LJ. Extracellular dopamine kinetic parameters consistent with amphetamine effects. Synapse 2019; 73:e22129. [DOI: 10.1002/syn.22129] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2019] [Revised: 08/20/2019] [Accepted: 08/22/2019] [Indexed: 02/03/2023]
Affiliation(s)
- Anna C. Felmer
- Division of Pharmacology College of Pharmacy The Ohio State University Columbus Ohio
| | - Marnie T. Janson
- Division of Pharmacology College of Pharmacy The Ohio State University Columbus Ohio
| | - Katherine E. Summers
- Division of Pharmacology College of Pharmacy The Ohio State University Columbus Ohio
| | - Lane J. Wallace
- Division of Pharmacology College of Pharmacy The Ohio State University Columbus Ohio
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Rooney KE, Wallace LJ. Computational modeling of extracellular dopamine kinetics suggests low probability of neurotransmitter release. Synapse 2015; 69:515-25. [PMID: 26248886 DOI: 10.1002/syn.21845] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [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: 05/13/2015] [Revised: 06/25/2015] [Accepted: 07/11/2015] [Indexed: 02/03/2023]
Abstract
Dopamine in the striatum signals the saliency of current environmental input and is involved in learned formation of appropriate responses. The regular baseline-firing rate of dopaminergic neurons suggests that baseline dopamine is essential for proper brain function. The first goal of the study was to estimate the likelihood of full exocytotic dopamine release associated with each firing event under baseline conditions. A computer model of extracellular space associated with a single varicosity was developed using the program MCell to estimate kinetics of extracellular dopamine. Because the literature provides multiple kinetic values for dopamine uptake depending on the system tested, simulations were run using different kinetic parameters. With all sets of kinetic parameters evaluated, at most, 25% of a single vesicle per varicosity would need to be released per firing event to maintain a 5-10 nM extracellular dopamine concentration, the level reported by multiple microdialysis experiments. The second goal was to estimate the fraction of total amount of stored dopamine released during a highly stimulated condition. This was done using the same model system to simulate published measurements of extracellular dopamine following electrical stimulation of striatal slices in vitro. The results suggest the amount of dopamine release induced by a single electrical stimulation may be as large as the contents of two vesicles per varicosity. We conclude that dopamine release probability at any particular varicosity is low. This suggests that factors capable of increasing release probability could have a powerful effect on sculpting dopamine signals.
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Affiliation(s)
- Katherine E Rooney
- Division of Pharmacology, College of Pharmacy, the Ohio State University, 500 W. 12th Avenue Columbus, Ohio, 43210
| | - Lane J Wallace
- Division of Pharmacology, College of Pharmacy, the Ohio State University, 500 W. 12th Avenue Columbus, Ohio, 43210.,500 West 12th Avenue Columbus, Ohio, 43210
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Xin HL, He XR, Li W, Zhou ZD, Zhang S, Wang GJ. The effect of borneol on the concentration of meropenem in rat brain and blood. J Asian Nat Prod Res 2014; 16:648-657. [PMID: 24827508 DOI: 10.1080/10286020.2014.916282] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2013] [Accepted: 04/15/2014] [Indexed: 06/03/2023]
Abstract
Meropenem is a carbapenem antibiotic with a wide spectrum of activity against both Gram-positive and Gram-negative bacteria. Because of its clinical efficacy, meropenem is an excellent choice for the treatment of serious infections in both adults and children. The knowledge of tissue concentrations of antibiotic in an infection site is valuable for the prediction of treatment outcome. The aim of the present study is to investigate the effect of borneol on the concentration of meropenem in rat brain and blood and to find the potential relationships of the combined use of medicine and traditional Chinese medicine. Analysis of meropenem in the dialysates was achieved using the microdialysis technique and HPLC. At 40 min after the administration of an intraperitoneal injection of meropenem, the concentration of meropenem in brain in borneol+meropenem group was 2.25 (0.35) μg ml(-1), which was significantly higher than that in meropenem group [1.20 (0.12) μg ml(-1); P < 0.01]. Within 80 min of drug administration, the AUCbrain/AUCblood (area under the curve, AUC) in the borneol+meropenem group was 1.2 times that of the meropenem group. Borneol can increase the concentration of meropenem in the cerebrospinal fluid, but has no influence on its blood concentration. This study represents a successful application of the microdialysis technique, which is an effective method for the study of pharmacokinetics of meropenem.
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Affiliation(s)
- Hai-Li Xin
- a Department of Pharmaceutical Care , The General Hospital of the People's Liberation Army , Beijing 100853 , China
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9
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Slaney TR, Mabrouk OS, Porter-Stransky KA, Aragona BJ, Kennedy RT. Chemical gradients within brain extracellular space measured using low flow push-pull perfusion sampling in vivo. ACS Chem Neurosci 2013; 4:321-9. [PMID: 23421683 DOI: 10.1021/cn300158p] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Although populations of neurons are known to vary on the micrometer scale, little is known about whether basal concentrations of neurotransmitters also vary on this scale. We used low-flow push-pull perfusion to test if such chemical gradients exist between several small brain nuclei. A miniaturized polyimide-encased push-pull probe was developed and used to measure basal neurotransmitter spatial gradients within brain of live animals with 0.004 mm(3) resolution. We simultaneously measured dopamine (DA), norepinephrine, serotonin (5-HT), glutamate, γ-aminobutyric acid (GABA), aspartate (Asp), glycine (Gly), acetylcholine (ACh), and several neurotransmitter metabolites. Significant differences in basal concentrations between midbrain regions as little as 200 μm apart were observed. For example, dopamine in the ventral tegmental area (VTA) was 4.8 ± 1.5 nM but in the red nucleus was 0.5 ± 0.2 nM. Regions of high glutamate concentration and variability were found within the VTA of some individuals, suggesting hot spots of glutamatergic activity. Measurements were also made within the nucleus accumbens core and shell. Differences were not observed in dopamine and 5-HT in the core and shell; but their metabolites homovanillic acid (460 ± 60 nM and 130 ± 60 nM respectively) and 5-hydroxyindoleacetic acid (720 ± 200 nM and 220 ± 50 nM respectively) did differ significantly, suggesting differences in dopamine and 5-HT activity in these brain regions. Maintenance of these gradients depends upon a variety of mechanisms. Such gradients likely underlie highly localized effects of drugs and control of behavior that have been found using other techniques.
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Affiliation(s)
- Thomas R. Slaney
- Department of Chemistry, University of Michigan, 930 N. University Ave. Ann
Arbor, Michigan 48109, United States
| | - Omar S. Mabrouk
- Department of Chemistry, University of Michigan, 930 N. University Ave. Ann
Arbor, Michigan 48109, United States
| | - Kirsten A. Porter-Stransky
- Department of Psychology, University of Michigan, 530 Church St., Ann Arbor,
Michigan 48109, United States
| | - Brandon J. Aragona
- Department of Psychology, University of Michigan, 530 Church St., Ann Arbor,
Michigan 48109, United States
| | - Robert T. Kennedy
- Department of Chemistry, University of Michigan, 930 N. University Ave. Ann
Arbor, Michigan 48109, United States
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Zhu J, Bardo MT, Green TA, Wedlund PJ, Dwoskin LP. Nicotine increases dopamine clearance in medial prefrontal cortex in rats raised in an enriched environment. J Neurochem 2011; 103:2575-88. [PMID: 17953677 DOI: 10.1111/j.1471-4159.2007.04951.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Environmental enrichment results in differential behavioral and neurochemical responsiveness to nicotine. The present study investigates dopamine clearance (CL(DA) ) in striatum and medial prefrontal cortex (mPFC) using in vivo voltammetry in rats raised in enriched (EC) or impoverished conditions (IC) and administered nicotine (0.4 mg/kg) or saline. Baseline CL(DA) in striatum or mPFC was not different between EC and IC. Across repeated DA application, striatal CL(DA) increased in saline-control EC and IC. CL(DA) increased in mPFC in saline-control IC; CL(DA) did not change in saline-control EC. Thus, enrichment differentially alters dynamic responses of the dopamine transporter (DAT) to repeated DA application in mPFC, but not in striatum. In EC, nicotine increased mPFC CL(DA) compared to saline-control, but had no effect on CL(DA) in IC; nicotine had no effect in striatum in EC or IC. Compared to respective saline-controls, nicotine increased dihydroxyphenylacetic acid content in striatum and mPFC in EC, but not in IC. Nicotine also had no effect on DA content in striatum or mPFC in EC or IC. Results indicate that enrichment eliminated the dynamic response of mPFC DAT to repeated DA application in saline-control and augmented the nicotine-induced increase in DAT function in mPFC, but not in striatum.
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Affiliation(s)
- Jun Zhu
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, Lexington, Kentucky, USA
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11
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Kroener S, Chandler LJ, Phillips PEM, Seamans JK. Dopamine modulates persistent synaptic activity and enhances the signal-to-noise ratio in the prefrontal cortex. PLoS One 2009; 4:e6507. [PMID: 19654866 PMCID: PMC2715878 DOI: 10.1371/journal.pone.0006507] [Citation(s) in RCA: 125] [Impact Index Per Article: 8.3] [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] [Subscribe] [Scholar Register] [Received: 03/04/2009] [Accepted: 07/11/2009] [Indexed: 11/19/2022] Open
Abstract
Background The importance of dopamine (DA) for prefrontal cortical (PFC) cognitive functions is widely recognized, but its mechanisms of action remain controversial. DA is thought to increase signal gain in active networks according to an inverted U dose-response curve, and these effects may depend on both tonic and phasic release of DA from midbrain ventral tegmental area (VTA) neurons. Methodology/Principal Findings We used patch-clamp recordings in organotypic co-cultures of the PFC, hippocampus and VTA to study DA modulation of spontaneous network activity in the form of Up-states and signals in the form of synchronous EPSP trains. These cultures possessed a tonic DA level and stimulation of the VTA evoked DA transients within the PFC. The addition of high (≥1 µM) concentrations of exogenous DA to the cultures reduced Up-states and diminished excitatory synaptic inputs (EPSPs) evoked during the Down-state. Increasing endogenous DA via bath application of cocaine also reduced Up-states. Lower concentrations of exogenous DA (0.1 µM) had no effect on the up-state itself, but they selectively increased the efficiency of a train of EPSPs to evoke spikes during the Up-state. When the background DA was eliminated by depleting DA with reserpine and alpha-methyl-p-tyrosine, or by preparing corticolimbic co-cultures without the VTA slice, Up-states could be enhanced by low concentrations (0.1–1 µM) of DA that had no effect in the VTA containing cultures. Finally, in spite of the concentration-dependent effects on Up-states, exogenous DA at all but the lowest concentrations increased intracellular current-pulse evoked firing in all cultures underlining the complexity of DA's effects in an active network. Conclusions/Significance Taken together, these data show concentration-dependent effects of DA on global PFC network activity and they demonstrate a mechanism through which optimal levels of DA can modulate signal gain to support cognitive functioning.
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Affiliation(s)
- Sven Kroener
- Department of Neurosciences, Medical University of South Carolina, Charleston, South Carolina, United States of America.
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Lapish CC, Ahn S, Evangelista LM, So K, Seamans JK, Phillips AG. Tolcapone enhances food-evoked dopamine efflux and executive memory processes mediated by the rat prefrontal cortex. Psychopharmacology (Berl) 2009; 202:521-30. [PMID: 18854987 DOI: 10.1007/s00213-008-1342-1] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.9] [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: 08/17/2008] [Accepted: 09/16/2008] [Indexed: 11/30/2022]
Abstract
BACKGROUND AND RATIONALE Genetic variations in catechol-O-methyl transferase (COMT) or administration of COMT inhibitors have a robust impact on cognition and executive function in humans. The COMT enzyme breaks down extracellular dopamine (DA) and has a particularly important role in the prefrontal cortex (PFC) where DA transporters are sparse. As such, the beneficial cognitive effects of the COMT inhibitor tolcapone are postulated to be the result of increased bioavailability of DA in the PFC. Furthermore, it has been shown previously that COMT inhibitors increase pharmacologically evoked DA but do not affect basal levels in the PFC. OBJECTIVES The current study characterized the ability of tolcapone to increase DA release in response to behaviorally salient stimuli and improve performance of the delayed spatial win-shift (DSWSh) task. RESULTS AND CONCLUSIONS Tolcapone enhanced PFC DA efflux associated with the anticipation and consumption of food when compared to saline controls. Chronic and acute treatment with tolcapone also reduced the number of errors committed during acquisition of the DSWSh. However, no dissociable effects were observed in experiments designed to selectively assay encoding or recall in well-trained animals, as both experiments showed improvement with tolcapone treatment. Taken together, these data suggest a generalized positive influence on cognition. Furthermore, these data support the conclusion of Apud and Weinberger (CNS Drugs 21:535-557, 2007) that agents which selectively potentiate PFC DA release may confer cognitive enhancement without the unwanted side effects produced by drugs that increase basal DA levels in cortical and subcortical brain regions.
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Affiliation(s)
- C C Lapish
- Department of Psychiatry, University of British Columbia, 2255 Wesbrook Mall, Vancouver BCV6T2A1, Canada.
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13
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Mulla IAL, Lowry JP, Serra PA, O'Neill RD. Development of a voltammetric technique for monitoring brain dopamine metabolism: compensation for interference caused by DOPAC electrogenerated during homovanillic acid detection. Analyst 2009; 134:893-8. [DOI: 10.1039/b810227a] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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14
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Adachi YU, Watanabe K, Satoh T, Vizi ES. Halothane potentiates the effect of methamphetamine and nomifensine on extracellular dopamine levels in rat striatum: a microdialysis study. Br J Anaesth 2001; 86:837-45. [PMID: 11573593 DOI: 10.1093/bja/86.6.837] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Brain microdialysis was used to study the in vivo release and metabolism of dopamine (DA) in the rat striatum during halothane anaesthesia. Concentrations were measured in microdialysates collected every 20 min and applied directly to an on-line high-performance liquid chromatograph. Halothane was administered at concentrations of 0.5, 1.0, 1.5 and 2.0%. In another series of experiments, rats were treated intraperitoneally or locally with methamphetamine, a drug of abuse, or with nomifensine, a dopamine uptake blocker and antidepressant, in combination with 0.5 or 1.5% halothane. Halothane anaesthesia did not affect the dialysate (extracellular) concentration of DA at 2.0%. By contrast, the concentrations of DA metabolites [3-methoxytyramine (3-MT), 3,4-dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA)] increased during inhaled halothane anaesthesia in a dose-dependent manner and recovered after anaesthesia. Halothane potentiated the ability of methamphetamine to increase the extracellular concentration of DA when administered systemically, whereas only a small increase in DA accumulation was seen when methamphetamine was administered locally via the perfusate. Similarly, the increase in extracellular DA was accentuated by systemic nomifensine during halothane anaesthesia, but no obvious enhancement was observed when it was applied locally. It has been shown that the neurotoxic effect of methamphetamine is mediated by the suboxidation of DA released from the cytoplasm into the extracellular space and transformed into highly reactive free radicals. On the basis of our results, it is suggested that care should be exercised when halothane anaesthesia is used in patients abusing phenylethylamines (amphetamines) or being treated with DA uptake blockers (nomifensine).
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Affiliation(s)
- Y U Adachi
- Department of Anesthesiology, National Defense Medical College, Tokorozawa, Saitama, Japan
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Teismann P, Ferger B. The salicylate hydroxylation assay to measure hydroxyl free radicals induced by local application of glutamate in vivo or induced by the Fenton reaction in vitro. Brain Res Brain Res Protoc 2000; 5:204-10. [PMID: 10775842 DOI: 10.1016/s1385-299x(00)00014-3] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The direct measurement of hydroxyl radicals in vivo is extremely difficult. Therefore, the indirect determination of hydroxyl radicals using salicylate (2-hydroxybenzoate) is widely accepted. Reverse microdialysis with glutamate led to a dose-dependent production of hydroxyl free radicals indicated by the hydroxylation adduct of salicylate, namely 2,3-dihydroxybenzoic acid. The local stimulation of hydroxyl free radical formation seems to be suitable to investigate a radical-scavenging property of potential neuroprotective drugs. In vitro experiments using the Fenton reaction may be a helpful tool to assess whether or not a substance is able to act as a radical scavenger in a cell free environment, which is easy to handle and a simple screening method before in vivo experiments were performed. In the present study we present an in vivo approach using local application of glutamate into the striatum and an in vitro screening using the Fenton reaction to induce hydroxyl radical formation. The main goal is to reliable measure hydroxyl free radicals, which are the most reactive oxygen radicals in biology and medicine.
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Affiliation(s)
- P Teismann
- Institute of Pharmacology and Toxicology, Faculty of Pharmacy, University of Marburg, Ketzerbach 63, D-35032, Marburg, Germany
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Cass WA, Manning MW, Dugan MT. Effects of neurotoxic doses of methamphetamine on potassium and amphetamine evoked overflow of dopamine in the striatum of awake rats. Neurosci Lett 1998; 248:175-8. [PMID: 9654337 DOI: 10.1016/s0304-3940(98)00374-7] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [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] [Indexed: 02/08/2023]
Abstract
The effects of neurotoxic doses of methamphetamine on basal and evoked overflow of dopamine in the striatum were examined in awake rats using microdialysis. Male Fischer-344 rats were administered methamphetamine (5 mg/kg s.c.) or saline four times in 1 day at 2-h intervals. Microdialysis experiments were carried out 1 week later. Basal levels of dopamine, 3,4-dihydroxyphenylacetic acid, and homovanillic acid were reduced in the striatum of the methamphetamine-treated animals. Local application of excess potassium (100 mM) and amphetamine (100 microM), and intraperitoneal injection of amphetamine (1.5 mg/ kg), led to increased levels of extracellular dopamine in the striatum of both methamphetamine- and saline-treated rats. However, the increase was significantly less in the methamphetamine-treated animals. Tissue levels of dopamine and metabolites were reduced in the striata of rats treated with methamphetamine. These results indicate that treatment with neurotoxic doses of methamphetamine can lead to functional changes in dopamine release in the striatum of Fischer-344 rats.
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Affiliation(s)
- W A Cass
- Department of Anatomy and Neurobiology, MN 224 Chandler Medical Center, University of Kentucky College of Medicine, Lexington 40536 0084, USA.
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Abstract
Delayed tissue damage is proposed to be caused by reactive oxygen species. We investigated the effects of microdialysis probe penetration into rat piriform cortex on hydrogen peroxide (H2O2) in brain extracellular fluid (ECF). H2O2 decreased immediately after probe insertion into the brain, but increased over 300% in samples within minutes after collection. We assessed H2O2 changes in vitro in microdialysis perfusion media containing various ascorbic acid concentrations and confirmed ascorbic acid is a source of H2O2. We conclude that decreased H2O2 concentrations in perfusion media as it passes through the brain reflect an extracellular antioxidant effect, whereas the increase in H2O2 with time after sample collection indicates that H2O2 generating substances are present in ECF. Thus, the potential for producing reactive oxygen species in brain ECF exists following penetration injury, especially if transition metals are released into the neuronal microenvironment.
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Affiliation(s)
- M E Layton
- Department of Psychiatry and Behavioral Sciences, University of Washington, Seattle 98195, USA.
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