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Consequences of Acute or Chronic Methylphenidate Exposure Using Ex Vivo Neurochemistry and In Vivo Electrophysiology in the Prefrontal Cortex and Striatum of Rats. Int J Mol Sci 2022; 23:ijms23158588. [PMID: 35955717 PMCID: PMC9369023 DOI: 10.3390/ijms23158588] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2022] [Revised: 07/29/2022] [Accepted: 08/01/2022] [Indexed: 01/27/2023] Open
Abstract
Methylphenidate (MPH) is among the main drugs prescribed to treat patients with attention-deficit and hyperactivity disease (ADHD). MPH blocks both the norepinephrine and dopamine reuptake transporters (NET and DAT, respectively). Our study was aimed at further understanding the mechanisms by which MPH could modulate neurotransmitter efflux, using ex vivo radiolabelled neurotransmitter assays isolated from rats. Here, we observed significant dopamine and norepinephrine efflux from the prefrontal cortex (PFC) after MPH (100 µM) exposure. Efflux was mediated by both dopamine and norepinephrine terminals. In the striatum, MPH (100 µM) triggered dopamine efflux through both sodium- and vesicular-dependent mechanisms. Chronic MPH exposure (4 mg/kg/day/animal, voluntary oral intake) for 15 days, followed by a 28-day washout period, increased the firing rate of PFC pyramidal neurons, assessed by in vivo extracellular single-cell electrophysiological recordings, without altering the responses to locally applied NMDA, via micro-iontophoresis. Furthermore, chronic MPH treatment resulted in decreased efficiency of extracellular dopamine to modulate NMDA-induced firing activities of medium spiny neurons in the striatum, together with lower MPH-induced (100 µM) dopamine outflow, suggesting desensitization to both dopamine and MPH in striatal regions. These results indicate that MPH can modulate neurotransmitter efflux in brain regions enriched with dopamine and/or norepinephrine terminals. Further, long-lasting alterations of striatal and prefrontal neurotransmission were observed, even after extensive washout periods. Further studies will be needed to understand the clinical implications of these findings.
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Altidor LKP, Bruner MM, Deslauriers JF, Garman TS, Ramirez S, Dirr EW, Olczak KP, Maurer AP, Lamb DG, Otto KJ, Burke SN, Bumanglag AV, Setlow B, Bizon JL. Acute vagus nerve stimulation enhances reversal learning in rats. Neurobiol Learn Mem 2021; 184:107498. [PMID: 34332068 DOI: 10.1016/j.nlm.2021.107498] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Revised: 07/01/2021] [Accepted: 07/24/2021] [Indexed: 01/19/2023]
Abstract
Cognitive flexibility is a prefrontal cortex-dependent neurocognitive process that enables behavioral adaptation in response to changes in environmental contingencies. Electrical vagus nerve stimulation (VNS) enhances several forms of learning and neuroplasticity, but its effects on cognitive flexibility have not been evaluated. In the current study, a within-subjects design was used to assess the effects of VNS on performance in a novel visual discrimination reversal learning task conducted in touchscreen operant chambers. The task design enabled simultaneous assessment of acute VNS both on reversal learning and on recall of a well-learned discrimination problem. Acute VNS delivered in conjunction with stimuli presentation during reversal learning reliably enhanced learning of new reward contingencies. Enhancement was not observed, however, if VNS was delivered during the session but was not coincident with presentation of to-be-learned stimuli. In addition, whereas VNS delivered at 30 HZ enhanced performance, the same enhancement was not observed using 10 or 50 Hz. Together, these data show that acute VNS facilitates reversal learning and indicate that the timing and frequency of the VNS are critical for these enhancing effects. In separate rats, administration of the norepinephrine reuptake inhibitor atomoxetine also enhanced reversal learning in the same task, consistent with a noradrenergic mechanism through which VNS enhances cognitive flexibility.
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Affiliation(s)
| | - Matthew M Bruner
- Department of Neuroscience, University of Florida, Gainesville, FL, USA
| | | | - Tyler S Garman
- Department of Neuroscience, University of Florida, Gainesville, FL, USA
| | - Saúl Ramirez
- Department of Neuroscience, University of Florida, Gainesville, FL, USA
| | - Elliott W Dirr
- J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville, FL, USA
| | - Kaitlynn P Olczak
- J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville, FL, USA
| | - Andrew P Maurer
- Department of Neuroscience, University of Florida, Gainesville, FL, USA; J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville, FL, USA; Evelyn F. & William L. McKnight Brain Institute, University of Florida, USA; Engineering School of Sustainable Infrastructure and Environment, University of Florida, Gainesville, FL, USA
| | - Damon G Lamb
- Department of Neuroscience, University of Florida, Gainesville, FL, USA; Department of Psychiatry, University of Florida, Gainesville, FL, USA; J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville, FL, USA; Evelyn F. & William L. McKnight Brain Institute, University of Florida, USA; Brain Rehabilitation Research Center, Malcom Randall VAMC, Gainesville, FL, USA
| | - Kevin J Otto
- Department of Neuroscience, University of Florida, Gainesville, FL, USA; J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville, FL, USA; Evelyn F. & William L. McKnight Brain Institute, University of Florida, USA
| | - Sara N Burke
- Department of Neuroscience, University of Florida, Gainesville, FL, USA; Evelyn F. & William L. McKnight Brain Institute, University of Florida, USA
| | - Argyle V Bumanglag
- Department of Neuroscience, University of Florida, Gainesville, FL, USA; Evelyn F. & William L. McKnight Brain Institute, University of Florida, USA
| | - Barry Setlow
- Department of Psychiatry, University of Florida, Gainesville, FL, USA; Evelyn F. & William L. McKnight Brain Institute, University of Florida, USA
| | - Jennifer L Bizon
- Department of Neuroscience, University of Florida, Gainesville, FL, USA; Evelyn F. & William L. McKnight Brain Institute, University of Florida, USA.
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Abstract
Background:Tics, defined as quick, rapid, sudden, recurrent, non-rhythmic motor movements or vocalizations are required components of Tourette Syndrome (TS) - a complex disorder characterized by the presence of fluctuating, chronic motor and vocal tics, and the presence of co-existing neuropsychological problems. Despite many advances, the underlying pathophysiology of tics/TS remains unknown.Objective:To address a variety of controversies surrounding the pathophysiology of TS. More specifically: 1) the configuration of circuits likely involved; 2) the role of inhibitory influences on motor control; 3) the classification of tics as either goal-directed or habitual behaviors; 4) the potential anatomical site of origin, e.g. cortex, striatum, thalamus, cerebellum, or other(s); and 5) the role of specific neurotransmitters (dopamine, glutamate, GABA, and others) as possible mechanisms (Abstract figure).Methods:Existing evidence from current clinical, basic science, and animal model studies are reviewed to provide: 1) an expanded understanding of individual components and the complex integration of the Cortico-Basal Ganglia-Thalamo-Cortical (CBGTC) circuit - the pathway involved with motor control; and 2) scientific data directly addressing each of the aforementioned controversies regarding pathways, inhibition, classification, anatomy, and neurotransmitters.Conclusion:Until a definitive pathophysiological mechanism is identified, one functional approach is to consider that a disruption anywhere within CBGTC circuitry, or a brain region inputting to the motor circuit, can lead to an aberrant message arriving at the primary motor cortex and enabling a tic. Pharmacologic modulation may be therapeutically beneficial, even though it might not be directed toward the primary abnormality.
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Affiliation(s)
- Harvey S. Singer
- Department of Neurology, Johns Hopkins Hospital, Baltimore, MD, United States
| | - Farhan Augustine
- Department of Neurology, Johns Hopkins Hospital, Baltimore, MD, United States
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Augustine F, Singer HS. Merging the Pathophysiology and Pharmacotherapy of Tics. Tremor Other Hyperkinet Mov (N Y) 2019; 8:595. [PMID: 30643668 PMCID: PMC6329776 DOI: 10.7916/d8h14jtx] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2018] [Accepted: 09/28/2018] [Indexed: 12/14/2022] Open
Abstract
Background Anatomically, cortical-basal ganglia-thalamo-cortical (CBGTC) circuits have an essential role in the expression of tics. At the biochemical level, the proper conveyance of messages through these circuits requires several functionally integrated neurotransmitter systems. In this manuscript, evidence supporting proposed pathophysiological abnormalities, both anatomical and chemical is reviewed. In addition, the results of standard and emerging tic-suppressing therapies affecting nine separate neurotransmitter systems are discussed. The goal of this review is to integrate our current understanding of the pathophysiology of Tourette syndrome (TS) with present and proposed pharmacotherapies for tic suppression. Methods For this manuscript, literature searches were conducted for both current basic science and clinical information in PubMed, Google-Scholar, and other scholarly journals to September 2018. Results The precise primary site of abnormality for tics remains undetermined. Although many pathophysiologic hypotheses favor a specific abnormality of the cortex, striatum, or globus pallidus, others recognize essential influences from regions such as the thalamus, cerebellum, brainstem, and ventral striatum. Some prefer an alteration within direct and indirect pathways, whereas others believe this fails to recognize the multiple interactions within and between CBGTC circuits. Although research and clinical evidence supports involvement of the dopaminergic system, additional data emphasizes the potential roles for several other neurotransmitter systems. Discussion A greater understanding of the primary neurochemical defect in TS would be extremely valuable for the development of new tic-suppressing therapies. Nevertheless, recognizing the varied and complex interactions that exist in a multi-neurotransmitter system, successful therapy may not require direct targeting of the primary abnormality.
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Affiliation(s)
- Farhan Augustine
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Harvey S. Singer
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
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Gronier B, Savignac HM, Di Miceli M, Idriss SM, Tzortzis G, Anthony D, Burnet PWJ. Increased cortical neuronal responses to NMDA and improved attentional set-shifting performance in rats following prebiotic (B-GOS ®) ingestion. Eur Neuropsychopharmacol 2018; 28:211-224. [PMID: 29174530 PMCID: PMC5857269 DOI: 10.1016/j.euroneuro.2017.11.001] [Citation(s) in RCA: 62] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/03/2017] [Revised: 09/13/2017] [Accepted: 11/02/2017] [Indexed: 12/13/2022]
Abstract
We have previously shown that prebiotics (dietary fibres that augment the growth of indigenous beneficial gut bacteria) such as Bimuno™ galacto-oligosaccharides (B-GOS®), increased N-methyl-D-aspartate (NMDA) receptor levels in the rat brain. The current investigation examined the functional correlates of these changes in B-GOS®-fed rats by measuring cortical neuronal responses to NMDA using in vivo NMDA micro-iontophoresis electrophysiology, and performance in the attentional set-shifting task. Adult male rats were supplemented with B-GOS® in the drinking water 3 weeks prior to in vivo iontophoresis or behavioural testing. Cortical neuronal responses to NMDA iontophoresis, were greater (+30%) in B-GOS® administered rats compared to non-supplemented controls. The intake of B-GOS® also partially hindered the reduction of NMDA responses by the glycine site antagonist, HA-966. In the attentional set-shifting task, B-GOS® -fed rats shifted from an intra-dimensional to an extra-dimensional set in fewer trials than controls, thereby indicating greater cognitive flexibility. An initial exploration into the mechanisms revealed that rats ingesting B-GOS® had increased levels of plasma acetate, and cortical GluN2B subunits and Acetyl Co-A Carboxylase mRNA. These changes were also observed in rats fed daily for 3 weeks with glyceryl triacetate, though unlike B-GOS®, cortical histone deacetylase (HDAC1, HDAC2) mRNAs were also increased which suggested an additional epigenetic action of direct acetate supplementation. Our data demonstrate that a pro-cognitive effect of B-GOS® intake in rats is associated with an increase in cortical NMDA receptor function, but the role of circulating acetate derived from gut bacterial fermentation of this prebiotic requires further investigation.
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Affiliation(s)
- Benjamin Gronier
- Leicester School of Pharmacy, De Montfort University, The Gateway, Leicester LE1 9BH, UK
| | | | - Mathieu Di Miceli
- Leicester School of Pharmacy, De Montfort University, The Gateway, Leicester LE1 9BH, UK
| | - Sherif M Idriss
- Center of Brain, Behavior and Metabolism (CBBM), University of Lubeck, 23562 Lubeck, Germany
| | | | - Daniel Anthony
- Department of Pharmacology, University of Oxford, Oxford OX1 3QT, UK
| | - Philip W J Burnet
- Department of Psychiatry, University of Oxford, Warneford Hospital, Oxford OX3 7JX, UK.
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Blockade of α2-adrenergic receptors in prelimbic cortex: impact on cocaine self-administration in adult spontaneously hypertensive rats following adolescent atomoxetine treatment. Psychopharmacology (Berl) 2017; 234:2897-2909. [PMID: 28730282 PMCID: PMC5693724 DOI: 10.1007/s00213-017-4681-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/05/2017] [Accepted: 06/25/2017] [Indexed: 12/17/2022]
Abstract
RATIONALE Research with the spontaneously hypertensive rat (SHR) model of attention deficit/hyperactivity disorder demonstrated that chronic methylphenidate treatment during adolescence increased cocaine self-administration established during adulthood under a progressive ratio (PR) schedule. Compared to vehicle, chronic atomoxetine treatment during adolescence failed to increase cocaine self-administration under a PR schedule in adult SHR. OBJECTIVES We determined if enhanced noradrenergic transmission at α2-adrenergic receptors within prefrontal cortex contributes to this neutral effect of adolescent atomoxetine treatment in adult SHR. METHODS Following treatment from postnatal days 28-55 with atomoxetine (0.3 mg/kg) or vehicle, adult male SHR and control rats from Wistar-Kyoto (WKY) and Wistar (WIS) strains were trained to self-administer 0.3 mg/kg cocaine. Self-administration performance was evaluated under a PR schedule of cocaine delivery following infusion of the α2-adrenergic receptor antagonist idazoxan (0 and 10-56 μg/side) directly into prelimbic cortex. RESULTS Adult SHR attained higher PR break points and had greater numbers of active lever responses and infusions than WKY and WIS. Idazoxan dose-dependently increased PR break points and active lever responses in SHR following adolescent atomoxetine vs. vehicle treatment. Behavioral changes were negligible after idazoxan pretreatment in SHR following adolescent vehicle or in WKY and WIS following adolescent atomoxetine or vehicle. CONCLUSIONS α2-Adrenergic receptor blockade in prelimbic cortex of SHR masked the expected neutral effect of adolescent atomoxetine on adult cocaine self-administration behavior. Moreover, greater efficacy of acute idazoxan challenge in adult SHR after adolescent atomoxetine relative to vehicle is consistent with the idea that chronic atomoxetine may downregulate presynaptic α2A-adrenergic autoreceptors in SHR.
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Acute orexigenic effect of agmatine involves interaction between central α2-adrenergic and GABAergic receptors. Biomed Pharmacother 2017; 93:939-947. [DOI: 10.1016/j.biopha.2017.07.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2017] [Revised: 06/14/2017] [Accepted: 07/03/2017] [Indexed: 02/02/2023] Open
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Neonatal domoic acid alters in vivo binding of [ 11C]yohimbine to α 2-adrenoceptors in adult rat brain. Psychopharmacology (Berl) 2016; 233:3779-3785. [PMID: 27557950 DOI: 10.1007/s00213-016-4416-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/30/2016] [Accepted: 08/10/2016] [Indexed: 12/31/2022]
Abstract
RATIONALE Epilepsy is a debilitating seizure disorder that affects approximately 50 million people. Noradrenaline reduces neuronal excitability, has anticonvulsant effects and is protective against seizure onset. OBJECTIVE We investigated the role of α2-adrenoceptors in vivo in a neonatal domoic acid (DOM) rat model of epilepsy. METHODS We injected male Sprague-Dawley rats daily from postnatal day 8-14 with saline or one of two sub-convulsive doses, 20 μg/kg (DOM20) or 60 μg/kg (DOM60) DOM, an AMPA/kainate receptor agonist. The rats were observed in open field, social interaction and forced swim tests at day 50, 75 and 98, respectively. At ~120 days of age, four rats per group were injected and scanned with [11C]yohimbine, an α2-adrenoceptor antagonist, and scanned in a Mediso micro positron emission tomography (PET) scanner to measure α2-adrenoceptor binding. RESULTS DOM60-treated rats spent more time in the periphery during the open field test and had a significant 26-33 % reduction in [11C]yohimbine binding in the hypothalamus, hippocampus and orbital prefrontal cortex compared to saline-treated rats. On the other hand, DOM20 rats had a significant 34-40 % increase in [11C]yohimbine binding in the hypothalamus, amygdala and entorhinal cortex compared to saline-treated rats, with no obvious behavioural differences. CONCLUSIONS The current data clearly indicate that low concentrations of DOM given to rats in their second week of life induces long-term changes in α2-adrenoceptor binding in rat brain that may have relevance to the progression of an epilepsy phenotype.
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Kirkpatrick DC, Walton LR, Edwards MA, Wightman RM. Quantitative analysis of iontophoretic drug delivery from micropipettes. Analyst 2016; 141:1930-8. [PMID: 26890395 PMCID: PMC4783294 DOI: 10.1039/c5an02530c] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Microiontophoresis is a drug delivery method in which an electric current is used to eject molecular species from a micropipette. It has been primarily utilized for neurochemical investigations, but is limited due to difficulty controlling and determining the ejected quantity. Consequently the concentration of an ejected species and the extent of the affected region are relegated to various methods of approximation. To address this, we investigated the principles underlying ejection rates and examined the concentration distribution in microiontophoresis using a combination of electrochemical, chromatographic, and fluorescence-based approaches. This involved a principal focus on how the iontophoretic barrel solution affects ejection characteristics. The ion ejection rate displayed a direct correspondence to the ionic mole fraction, regardless of the ejection current polarity. In contrast, neutral molecules are ejected by electroosmotic flow (EOF) at a rate proportional to the barrel solution concentration. Furthermore, the presence of EOF was observed from barrels containing high ionic strength solutions. In practice, use of a retaining current draws extracellular ions into the barrel and will alter the barrel solution composition. Even in the absence of a retaining current, diffusional exchange at the barrel tip will occur. Thus behavior of successive ejections may slightly differ. To account for this, electrochemical or fluorescence markers can be incorporated into the barrel solution in order to compare ejection quantities. These may also be used to provide an estimate of the ejected amount and distribution provided accurate use of calibration procedures.
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Affiliation(s)
- D C Kirkpatrick
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-3290, USA.
| | - L R Walton
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-3290, USA.
| | - M A Edwards
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-3290, USA.
| | - R M Wightman
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-3290, USA. and Neuroscience Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-3290, USA
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Noradrenergic signaling in the medial prefrontal cortex and amygdala differentially regulates vicarious trial-and-error in a spatial decision-making task. Behav Brain Res 2015; 297:104-11. [PMID: 26341318 DOI: 10.1016/j.bbr.2015.09.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2015] [Revised: 08/29/2015] [Accepted: 09/01/2015] [Indexed: 11/23/2022]
Abstract
In uncertain choice situations, we deliberately search and evaluate possible options before taking an action. Once we form a preference regarding the current situation, we take an action more automatically and with less deliberation. In rats, the deliberation process can be seen in vicarious trial-and-error behavior (VTE), which is a head-orienting behavior toward options at a choice point. Recent neurophysiological findings suggest that VTE reflects the rat's thinking about future options as deliberation, expectation, and planning when rats feel conflict. VTE occurs depending on the demand: an increase occurs during initial learning, and a decrease occurs with progression in learning. However, the brain circuit underlying the regulation of VTE has not been thoroughly examined. In situations in which VTE often appears, the medial prefrontal cortex (mPFC) and the amygdala (AMY) are crucial for learning and decision making. Our previous study reported that noradrenaline regulates VTE. Here, to investigate whether the mPFC and AMY are involved in regulation of VTE, we examined the effects of local injection of clonidine, an alpha2 adrenergic autoreceptor agonist, into either region in rats during VTE and choice behavior during a T-maze choice task. Injection of clonidine into either region impaired selection of the advantageous choice in the task. Furthermore, clonidine injection into the mPFC suppressed occurrence of VTE in the early phase of the task, whereas injection into the AMY inhibited the decrease in VTE in the later phase and thus maintained a high level of VTE throughout the task. These results suggest that the mPFC and AMY play a role in the increase and decrease in VTE, respectively, and that noradrenergic mechanisms mediate the dynamic regulation of VTE over experiences.
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Di Miceli M, Gronier B. Psychostimulants and atomoxetine alter the electrophysiological activity of prefrontal cortex neurons, interaction with catecholamine and glutamate NMDA receptors. Psychopharmacology (Berl) 2015; 232:2191-205. [PMID: 25572531 DOI: 10.1007/s00213-014-3849-y] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/07/2014] [Accepted: 12/12/2014] [Indexed: 12/29/2022]
Abstract
RATIONALE Attention-deficit hyperactivity disorder (ADHD) is the most frequently diagnosed neuropsychiatric disorder in childhood. Currently available ADHD drugs include the psychostimulants methylphenidate (MPH) and D-amphetamine (D-AMP), acting on norepinephrine and dopamine transporters/release, and atomoxetine (ATX), a selective norepinephrine uptake inhibitor. Recent evidence suggests an involvement of glutamate neurotransmission in the pathology and treatment of ADHD, via mechanisms to be clarified. OBJECTIVE We have investigated how ADHD drugs could modulate, through interaction with catecholamine receptors, basal and glutamate-induced excitability of pyramidal neurons in the prefrontal cortex (PFC), a region which plays a major role in control of attention and impulsivity. METHODS We have used the technique of extracellular single-unit recording in anaesthetised rats coupled with microiontophoresis. RESULTS Both MPH (1-3 mg/kg) and D-AMP (1-9 mg/kg) increased the firing activity of PFC neurons in a dopamine D1 receptor-dependent manner. ATX administration (1-6 mg/kg) also increased the firing of neurons, but this effect is not significantly reversed by D1 (SCH 23390) or alpha1 (prazosin) receptor antagonists but potentiated by alpha2 antagonist (yohimbine). All drugs induced a clear potentiation of the excitatory response of PFC neurons to the microiontophoretic application of the glutamate agonist N-methyl-D-aspartate (NMDA), but not to the glutamate agonist α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA). The potentiating effect of D-AMP on NMDA-induced activation of PFC neurons was partially reversed or prevented by dopamine D1 receptor blockade. CONCLUSION Our data shows that increase in excitability of PFC neurons in basal conditions and via NMDA receptor activation may be involved in the therapeutic response to ADHD drugs.
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Affiliation(s)
- Mathieu Di Miceli
- Leicester School of Pharmacy, De Montfort University, The Gateway, Leicester, LE1 9BH, UK
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Spencer RC, Devilbiss DM, Berridge CW. The cognition-enhancing effects of psychostimulants involve direct action in the prefrontal cortex. Biol Psychiatry 2015; 77:940-50. [PMID: 25499957 PMCID: PMC4377121 DOI: 10.1016/j.biopsych.2014.09.013] [Citation(s) in RCA: 117] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/29/2014] [Revised: 09/16/2014] [Accepted: 09/18/2014] [Indexed: 01/22/2023]
Abstract
Psychostimulants are highly effective in the treatment of attention-deficit/hyperactivity disorder. The clinical efficacy of these drugs is strongly linked to their ability to improve cognition dependent on the prefrontal cortex (PFC) and extended frontostriatal circuit. The procognitive actions of psychostimulants are only associated with low doses. Surprisingly, despite nearly 80 years of clinical use, the neurobiology of the procognitive actions of psychostimulants has only recently been systematically investigated. Findings from this research unambiguously demonstrate that the cognition-enhancing effects of psychostimulants involve the preferential elevation of catecholamines in the PFC and the subsequent activation of norepinephrine α2 and dopamine D1 receptors. In contrast, while the striatum is a critical participant in PFC-dependent cognition, where examined, psychostimulant action within the striatum is not sufficient to enhance cognition. At doses that moderately exceed the clinical range, psychostimulants appear to improve PFC-dependent attentional processes at the expense of other PFC-dependent processes (e.g., working memory, response inhibition). This differential modulation of PFC-dependent processes across dose appears to be associated with the differential involvement of noradrenergic α2 versus α1 receptors. Collectively, this evidence indicates that at low, clinically relevant doses, psychostimulants are devoid of the behavioral and neurochemical actions that define this class of drugs and instead act largely as cognitive enhancers (improving PFC-dependent function). This information has potentially important clinical implications as well as relevance for public health policy regarding the widespread clinical use of psychostimulants and for the development of novel pharmacologic treatments for attention-deficit/hyperactivity disorder and other conditions associated with PFC dysregulation.
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Affiliation(s)
- Robert C Spencer
- Department of Psychology, University of Wisconsin, Madison, Wisconsin
| | - David M Devilbiss
- Department of Psychology, University of Wisconsin, Madison, Wisconsin
| | - Craig W Berridge
- Department of Psychology, University of Wisconsin, Madison, Wisconsin.
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Lu Y, Li C, Zhou M, Luo P, Huang P, Tan J, Lu Q, Xu X, He Z, Guo L. Clonidine ameliorates cognitive impairment induced by chronic cerebral hypoperfusion via up-regulation of the GABABR1 and GAD67 in hippocampal CA1 in rats. Pharmacol Biochem Behav 2015; 132:96-102. [DOI: 10.1016/j.pbb.2015.01.018] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/24/2014] [Revised: 01/21/2015] [Accepted: 01/26/2015] [Indexed: 12/20/2022]
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Bédard ACV, Schulz KP, Krone B, Pedraza J, Duhoux S, Halperin JM, Newcorn JH. Neural mechanisms underlying the therapeutic actions of guanfacine treatment in youth with ADHD: a pilot fMRI study. Psychiatry Res 2015; 231:353-6. [PMID: 25659477 DOI: 10.1016/j.pscychresns.2015.01.012] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/19/2014] [Revised: 11/06/2014] [Accepted: 01/12/2015] [Indexed: 01/23/2023]
Abstract
Twenty-five youth with attention-deficit/hyperactivity disorder (ADHD) were scanned with functional magnetic resonance imaging (fMRI) while performing a Go/No-go task before and after 6-8 weeks of randomized once-daily treatment with either the α₂A-adrenergic receptor agonist guanfacine or placebo. Clinical improvement was greater for guanfacine than placebo and was differentially associated with reduced activation for guanfacine compared with placebo in the right midcingulate cortex/supplementary motor area and the left posterior cingulate cortex.
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Affiliation(s)
- Anne-Claude V Bédard
- Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Kurt P Schulz
- Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY, USA.
| | - Beth Krone
- Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Juan Pedraza
- Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Stephanie Duhoux
- Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Jeffrey M Halperin
- Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY, USA; Department of Psychology, Queens College of the City University of New York, Flushing, NY, USA
| | - Jeffrey H Newcorn
- Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY, USA
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Espay AJ, LeWitt PA, Kaufmann H. Norepinephrine deficiency in Parkinson's disease: The case for noradrenergic enhancement. Mov Disord 2014; 29:1710-9. [PMID: 25297066 DOI: 10.1002/mds.26048] [Citation(s) in RCA: 169] [Impact Index Per Article: 16.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2014] [Revised: 09/02/2014] [Accepted: 09/11/2014] [Indexed: 12/28/2022] Open
Affiliation(s)
- Alberto J. Espay
- Gardner Family Center for Parkinson's Disease and Movement Disorders; Department of Neurology; University of Cincinnati; Cincinnati Ohio USA
| | - Peter A. LeWitt
- Departments of Neurology; Henry Ford Hospital and Wayne State University School of Medicine; West Bloomfield Michigan USA
| | - Horacio Kaufmann
- Dysautonomia Center; Department of Neurology; NYU School of Medicine; New York New York USA
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Marinho da Silva S, Carrettiero DC, Chadi DRF. Glutamate requires NMDA receptors to modulate alpha2 adrenoceptor in medulla oblongata cultured cells of newborn rats. Neurosci Lett 2014; 564:83-8. [PMID: 24530256 DOI: 10.1016/j.neulet.2014.02.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2013] [Revised: 01/27/2014] [Accepted: 02/03/2014] [Indexed: 11/19/2022]
Abstract
α2 Adrenoceptors (α2-ARs) are important in regulating the central control of blood pressure in medulla oblongata. However, it is unclear how this receptor is modulated by different receptors, especially the glutamatergic. In the present study, we studied the influence of ionotropic glutamatergic receptors over the α2-ARs in cultured cells of the medulla oblongata of newborn rats. For this purpose, the protein level of the α2-ARs was assessed after administration to the cultured cells of glutamate (glu), the agonists NMDA and kainate (KA), the NMDA receptor antagonist MK801 and the KA receptor antagonist DNQX. Results indicate that the α2-AR protein levels were increased after the treatments with glu and NMDA, and the addition of MK801 to this treatment thwarted this increase. Notwithstanding the fact that KA did not alter the receptor protein level, the combined treatment of DNQX with glu prevented the α2-AR protein modulation. In conclusion, the present study suggests that ionotropic glutamatergic receptors could be related to the α2-AR protein regulation in the medulla oblongata.
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Affiliation(s)
- Sergio Marinho da Silva
- Department of Physiology, Institute of Biosciences, University of São Paulo, São Paulo, Brazil
| | - Daniel C Carrettiero
- Centro de Ciências Naturais e Humanas, Universidade Federal do ABC (UFABC), Santo André, Brazil
| | - Débora R F Chadi
- Department of Physiology, Institute of Biosciences, University of São Paulo, São Paulo, Brazil.
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Gronier B, Waters S, Ponten H. The dopaminergic stabilizer pridopidine increases neuronal activity of pyramidal neurons in the prefrontal cortex. J Neural Transm (Vienna) 2013; 120:1281-94. [DOI: 10.1007/s00702-013-1002-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2012] [Accepted: 02/17/2013] [Indexed: 12/29/2022]
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Schulz KP, Clerkin SM, Fan J, Halperin JM, Newcorn JH. Guanfacine modulates the influence of emotional cues on prefrontal cortex activation for cognitive control. Psychopharmacology (Berl) 2013; 226:261-71. [PMID: 23086020 PMCID: PMC3567242 DOI: 10.1007/s00213-012-2893-8] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/18/2012] [Accepted: 10/06/2012] [Indexed: 11/25/2022]
Abstract
RATIONALE Functional interactions between limbic regions that process emotions and frontal networks that guide response functions provide a substrate for emotional cues to influence behavior. Stimulation of postsynaptic α₂ adrenoceptors enhances the function of prefrontal regions in these networks. However, the impact of this stimulation on the emotional biasing of behavior has not been established. OBJECTIVES This study tested the effect of the postsynaptic α₂ adrenoceptor agonist guanfacine on the emotional biasing of response execution and inhibition in prefrontal cortex. METHODS Fifteen healthy young adults were scanned twice with functional magnetic resonance imaging while performing a face emotion go/no-go task following counterbalanced administration of single doses of oral guanfacine (1 mg) and placebo in a double-blind, cross-over design. RESULTS Lower perceptual sensitivity and less response bias for sad faces resulted in fewer correct responses compared to happy and neutral faces but had no effect on correct inhibitions. Guanfacine increased the sensitivity and bias selectively for sad faces, resulting in response accuracy comparable to happy and neutral faces, and reversed the valence-dependent variation in response-related activation in left dorsolateral prefrontal cortex (DLPFC), resulting in enhanced activation for response execution cued by sad faces relative to happy and neutral faces, in line with other frontoparietal regions. CONCLUSIONS These results provide evidence that guanfacine stimulation of postsynaptic α₂ adrenoceptors moderates DLPFC activation associated with the emotional biasing of response execution processes. The findings have implications for the α₂ adrenoceptor agonist treatment of attention-deficit hyperactivity disorder.
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Affiliation(s)
- Kurt P. Schulz
- Department of Psychiatry, The Mount Sinai School of Medicine, One Gustave L. Levy Place, Box 1230, New York, NY 10029, USA, Tel: +1 212 241 6623, Fax: +1 212 659 8986
| | - Suzanne M. Clerkin
- Department of Psychiatry, The Mount Sinai School of Medicine, One Gustave L. Levy Place, Box 1230, New York, NY 10029, USA
| | - Jin Fan
- Department of Psychiatry, The Mount Sinai School of Medicine, One Gustave L. Levy Place, Box 1230, New York, NY 10029, USA. Department of Psychology, Queens College of the City University of New York, Flushing, NY 11367, USA
| | - Jeffrey M. Halperin
- Department of Psychiatry, The Mount Sinai School of Medicine, One Gustave L. Levy Place, Box 1230, New York, NY 10029, USA. Department of Psychology, Queens College of the City University of New York, Flushing, NY 11367, USA
| | - Jeffrey H. Newcorn
- Department of Psychiatry, The Mount Sinai School of Medicine, One Gustave L. Levy Place, Box 1230, New York, NY 10029, USA
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Calligaris L, Vidoni A, Bruno I, Vidoni M, Barbi E. Efficacy of clonidine in hyperammonemia induced hyperexcitability syndrome. Paediatr Anaesth 2013; 23:202-4. [PMID: 23289776 DOI: 10.1111/pan.12088] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Affiliation(s)
- Lorenzo Calligaris
- Department of Pediatric Emergency; Institute for Maternal and Child Health - IRCCS ‘Burlo Garofolo’; Trieste; Italy
| | - Annarita Vidoni
- Intensive Care Unit; Institute for Maternal and Child Health - IRCCS ‘Burlo Garofolo’; Trieste; Italy
| | - Irene Bruno
- Department of Pediatric; Institute for Maternal and Child Health - IRCCS ‘Burlo Garofolo’; Trieste; Italy
| | - Michael Vidoni
- Department of Pediatric; Institute for Maternal and Child Health - IRCCS ‘Burlo Garofolo’; Trieste; Italy
| | - Egidio Barbi
- Department of Pediatric Emergency; Institute for Maternal and Child Health - IRCCS ‘Burlo Garofolo’; Trieste; Italy
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Frånberg O, Marcus MM, Svensson TH. Involvement of 5-HT2A receptor and α2-adrenoceptor blockade in the asenapine-induced elevation of prefrontal cortical monoamine outflow. Synapse 2012; 66:650-60. [DOI: 10.1002/syn.21551] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2011] [Accepted: 02/14/2012] [Indexed: 12/30/2022]
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Gottesmann C. The involvement of noradrenaline in rapid eye movement sleep mentation. Front Neurol 2011; 2:81. [PMID: 22180750 PMCID: PMC3235734 DOI: 10.3389/fneur.2011.00081] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2011] [Accepted: 11/23/2011] [Indexed: 01/19/2023] Open
Abstract
Noradrenaline, one of the main brain monoamines, has powerful central influences on forebrain neurobiological processes which support the mental activities occurring during the sleep-waking cycle. Noradrenergic neurons are activated during waking, decrease their firing rate during slow wave sleep, and become silent during rapid eye movement (REM) sleep. Although a low level of noradrenaline is still maintained during REM sleep because of diffuse extrasynaptic release without rapid withdrawal, the decrease observed during REM sleep contributes to the mentation disturbances that occur during dreaming, which principally resemble symptoms of schizophrenia but seemingly also of attention deficit hyperactivity disorder.
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Affiliation(s)
- Claude Gottesmann
- Département de Biologie, Université de Nice-Sophia AntipolisNice, France
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