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Wingert JC, Ramos JD, Reynolds SX, Gonzalez AE, Rose RM, Hegarty DM, Aicher SA, Bailey LG, Brown TE, Abbas AI, Sorg BA. Perineuronal Nets in the Rat Medial Prefrontal Cortex Alter Hippocampal-Prefrontal Oscillations and Reshape Cocaine Self-Administration Memories. J Neurosci 2024; 44:e0468242024. [PMID: 38991791 PMCID: PMC11340292 DOI: 10.1523/jneurosci.0468-24.2024] [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: 03/11/2024] [Revised: 06/20/2024] [Accepted: 06/25/2024] [Indexed: 07/13/2024] Open
Abstract
The medial prefrontal cortex (mPFC) is a major contributor to relapse to cocaine in humans and to reinstatement in rodent models of cocaine use disorder. The output from the mPFC is potently modulated by parvalbumin (PV)-containing fast-spiking interneurons, the majority of which are surrounded by perineuronal nets. We previously showed that treatment with chondroitinase ABC (ABC) reduced the consolidation and reconsolidation of a cocaine conditioned place preference memory. However, self-administration memories are more difficult to disrupt. Here we report in male rats that ABC treatment in the mPFC attenuated the consolidation and blocked the reconsolidation of a cocaine self-administration memory. However, reconsolidation was blocked when rats were given a novel, but not familiar, type of retrieval session. Furthermore, ABC treatment prior to, but not after, memory retrieval blocked reconsolidation. This same treatment did not alter a sucrose memory, indicating specificity for cocaine-induced memory. In naive rats, ABC treatment in the mPFC altered levels of PV intensity and cell firing properties. In vivo recordings from the mPFC and dorsal hippocampus (dHIP) during the novel retrieval session revealed that ABC prevented reward-associated increases in high-frequency oscillations and synchrony of these oscillations between the dHIP and mPFC. Together, this is the first study to show that ABC treatment disrupts reconsolidation of the original memory when combined with a novel retrieval session that elicits coupling between the dHIP and mPFC. This coupling after ABC treatment may serve as a fundamental signature for how to disrupt reconsolidation of cocaine memories and reduce relapse.
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Affiliation(s)
- Jereme C Wingert
- R.S. Dow Neurobiology, Legacy Research Institute, Portland, Oregon 97232
| | - Jonathan D Ramos
- R.S. Dow Neurobiology, Legacy Research Institute, Portland, Oregon 97232
| | | | - Angela E Gonzalez
- R.S. Dow Neurobiology, Legacy Research Institute, Portland, Oregon 97232
- Program in Neuroscience, Washington State University, Vancouver, Washington 98686
| | - R Mae Rose
- R.S. Dow Neurobiology, Legacy Research Institute, Portland, Oregon 97232
| | - Deborah M Hegarty
- Department of Chemical Physiology and Biochemistry, Oregon Health & Science University, Portland, Oregon 97239
| | - Sue A Aicher
- Department of Chemical Physiology and Biochemistry, Oregon Health & Science University, Portland, Oregon 97239
| | - Lydia G Bailey
- Program in Neuroscience, Washington State University, Pullman, Washington 99164
| | - Travis E Brown
- Program in Neuroscience, Washington State University, Pullman, Washington 99164
| | - Atheir I Abbas
- Departments of Behavioral Neuroscience, Oregon Health & Science University, Portland, Oregon 97239
- Psychiatry, Oregon Health & Science University, Portland, Oregon 97239
- Research Division, VA Portland Health Care System, Portland, Oregon 97239
| | - Barbara A Sorg
- R.S. Dow Neurobiology, Legacy Research Institute, Portland, Oregon 97232
- Program in Neuroscience, Washington State University, Vancouver, Washington 98686
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Wingert JC, Ramos JD, Reynolds SX, Gonzalez AE, Rose RM, Hegarty DM, Aicher SA, Bailey LG, Brown TE, Abbas AI, Sorg BA. Perineuronal nets in the rat medial prefrontal cortex alter hippocampal-prefrontal oscillations and reshape cocaine self-administration memories. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.02.05.577568. [PMID: 38370716 PMCID: PMC10871211 DOI: 10.1101/2024.02.05.577568] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/20/2024]
Abstract
The medial prefrontal cortex (mPFC) is a major contributor to relapse to cocaine in humans and to reinstatement behavior in rodent models of cocaine use disorder. Output from the mPFC is modulated by parvalbumin (PV)-containing fast-spiking interneurons, the majority of which are surrounded by perineuronal nets (PNNs). Here we tested whether chondroitinase ABC (ABC)- mediated removal of PNNs prevented the acquisition or reconsolidation of a cocaine self-administration memory. ABC injections into the dorsal mPFC prior to training attenuated the acquisition of cocaine self-administration. Also, ABC given 3 days prior to but not 1 hr after memory reactivation blocked cue-induced reinstatement. However, reduced reinstatement was present only in rats given a novel reactivation contingency, suggesting that PNNs are required for the updating of a familiar memory. In naive rats, ABC injections into mPFC did not alter excitatory or inhibitory puncta on PV cells but reduced PV intensity. Whole-cell recordings revealed a greater inter-spike interval 1 hr after ABC, but not 3 days later. In vivo recordings from the mPFC and dorsal hippocampus (dHIP) during novel memory reactivation revealed that ABC in the mPFC prevented reward-associated increases in beta and gamma activity as well as phase-amplitude coupling between the dHIP and mPFC. Together, our findings show that PNN removal attenuates the acquisition of cocaine self-administration memories and disrupts reconsolidation of the original memory when combined with a novel reactivation session. Further, reduced dHIP/mPFC coupling after PNN removal may serve as a key biomarker for how to disrupt reconsolidation of cocaine memories and reduce relapse.
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Angoa-Pérez M, Zagorac B, Francescutti DM, Shaffer ZD, Theis KR, Kuhn DM. Cocaine hydrochloride, cocaine methiodide and methylenedioxypyrovalerone (MDPV) cause distinct alterations in the structure and composition of the gut microbiota. Sci Rep 2023; 13:13754. [PMID: 37612353 PMCID: PMC10447462 DOI: 10.1038/s41598-023-40892-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Accepted: 08/17/2023] [Indexed: 08/25/2023] Open
Abstract
Cocaine is a highly addictive psychostimulant drug of abuse that constitutes an ongoing public health threat. Emerging research is revealing that numerous peripheral effects of this drug may serve as conditioned stimuli for its central reinforcing properties. The gut microbiota is emerging as one of these peripheral sources of input to cocaine reward. The primary objective of the present study was to determine how cocaine HCl and methylenedioxypyrovalerone, both of which powerfully activate central reward pathways, alter the gut microbiota. Cocaine methiodide, a quaternary derivative of cocaine that does not enter the brain, was included to assess peripheral influences on the gut microbiota. Both cocaine congeners caused significant and similar alterations of the gut microbiota after a 10-day course of treatment. Contrary to expectations, the effects of cocaine HCl and MDPV on the gut microbiota were most dissimilar. Functional predictions of metabolic alterations caused by the treatment drugs reaffirmed that the cocaine congeners were similar whereas MDPV was most dissimilar from the other two drugs and controls. It appears that the monoamine transporters in the gut mediate the effects of the treatment drugs. The effects of the cocaine congeners and MDPV on the gut microbiome may form the basis of interoceptive cues that can influence their abuse properties.
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Affiliation(s)
- Mariana Angoa-Pérez
- Research and Development Service, John D. Dingell VA Medical Center, Detroit, MI, USA.
- Department of Psychiatry and Behavioral Neurosciences, Wayne State University School of Medicine, Detroit, MI, USA.
| | - Branislava Zagorac
- Research and Development Service, John D. Dingell VA Medical Center, Detroit, MI, USA
- Department of Psychiatry and Behavioral Neurosciences, Wayne State University School of Medicine, Detroit, MI, USA
| | - Dina M Francescutti
- Research and Development Service, John D. Dingell VA Medical Center, Detroit, MI, USA
- Department of Psychiatry and Behavioral Neurosciences, Wayne State University School of Medicine, Detroit, MI, USA
| | - Zachary D Shaffer
- Department of Physiology, Wayne State University School of Medicine, Detroit, MI, USA
| | - Kevin R Theis
- Department of Biochemistry, Microbiology, and Immunology, Wayne State University School of Medicine, Detroit, MI, USA
| | - Donald M Kuhn
- Research and Development Service, John D. Dingell VA Medical Center, Detroit, MI, USA
- Department of Psychiatry and Behavioral Neurosciences, Wayne State University School of Medicine, Detroit, MI, USA
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Kuebler IRK, Jolton JA, Hermreck C, Hubbard NA, Wakabayashi KT. Contrasting dose-dependent effects of acute intravenous methamphetamine on lateral hypothalamic extracellular glucose dynamics in male and female rats. J Neurophysiol 2022; 128:819-836. [PMID: 36043803 PMCID: PMC9529272 DOI: 10.1152/jn.00257.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2022] [Revised: 08/22/2022] [Accepted: 08/24/2022] [Indexed: 11/22/2022] Open
Abstract
Glucose is the brain's primary energetic resource. The brain's use of glucose is dynamic, balancing delivery from the neurovasculature with local metabolism. Although glucose metabolism is known to differ in humans with and without methamphetamine use disorder (MUD), it is unknown how central glucose regulation changes with acute methamphetamine experience. Here, we determined how intravenous methamphetamine regulates extracellular glucose levels in a brain region implicated in MUD-like behavior, the lateral hypothalamus (LH). We measured extracellular LH glucose in awake adult male and female drug-naive Wistar rats using enzyme-linked amperometric glucose biosensors. Changes in LH glucose were monitored during a single session after: 1) natural nondrug stimuli (novel object presentation and a tail-touch), 2) increasing cumulative doses of intravenous methamphetamine (0.025, 0.05, 0.1, and 0.2 mg/kg), and 3) an injection of 60 mg of glucose. We found second-scale fluctuations in LH glucose in response to natural stimuli that differed by both stimulus type and sex. Although rapid, second-scale changes in LH glucose during methamphetamine injections were variable, slow, minute-scale changes following most injections were robust and resulted in a reduction in LH glucose levels. Dose and sex differences at this timescale indicated that female rats may be more sensitive to the impact of methamphetamine on central glucose regulation. These findings suggest that the effects of MUD on healthy brain function may be linked to how methamphetamine alters extracellular glucose regulation in the LH and point to possible mechanisms by which methamphetamine influences central glucose metabolism more broadly.NEW & NOTEWORTHY Enzyme-linked glucose biosensors were used to monitor lateral hypothalamic (LH) extracellular fluctuations during nondrug stimuli and intravenous methamphetamine injections in drug-naive awake male and female rats. Second-scale glucose changes occurred after nondrug stimuli, differing by modality and sex. Robust minute-scale decreases followed most methamphetamine injections. Sex differences at the minute-scale indicate female central glucose regulation is more sensitive to methamphetamine effects. We discuss likely mechanisms underlying these fluctuations, and their implications in methamphetamine use disorder.
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Affiliation(s)
- Isabel R K Kuebler
- Neurocircuitry of Motivated Behavior Laboratory, Department of Psychology, University of Nebraska-Lincoln, Lincoln, Nebraska
| | - Joshua A Jolton
- Neurocircuitry of Motivated Behavior Laboratory, Department of Psychology, University of Nebraska-Lincoln, Lincoln, Nebraska
| | - Chase Hermreck
- Neurocircuitry of Motivated Behavior Laboratory, Department of Psychology, University of Nebraska-Lincoln, Lincoln, Nebraska
| | - Nicholas A Hubbard
- Neurocircuitry of Motivated Behavior Laboratory, Department of Psychology, University of Nebraska-Lincoln, Lincoln, Nebraska
| | - Ken T Wakabayashi
- Neurocircuitry of Motivated Behavior Laboratory, Department of Psychology, University of Nebraska-Lincoln, Lincoln, Nebraska
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Gonzalez AE, Jorgensen ET, Ramos JD, Harkness JH, Aadland JA, Brown TE, Sorg BA. Impact of Perineuronal Net Removal in the Rat Medial Prefrontal Cortex on Parvalbumin Interneurons After Reinstatement of Cocaine Conditioned Place Preference. Front Cell Neurosci 2022; 16:932391. [PMID: 35966203 PMCID: PMC9366391 DOI: 10.3389/fncel.2022.932391] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Accepted: 06/22/2022] [Indexed: 11/30/2022] Open
Abstract
Parvalbumin (PV)-positive cells are GABAergic fast-spiking interneurons that modulate the activity of pyramidal neurons in the medial prefrontal cortex (mPFC) and their output to brain areas associated with learning and memory. The majority of PV cells within the mPFC are surrounded by a specialized extracellular matrix structure called the perineuronal net (PNN). We have shown that removal of PNNs with the enzyme chondroitinase-ABC (Ch-ABC) in the mPFC prevents the consolidation and reconsolidation of cocaine-associated conditioned place preference (CPP) memories. Here we examined the extent to which retrieval of a CPP memory during cocaine-primed reinstatement altered the levels and function of PV neurons and their surrounding PNNs during the reconsolidation period. We further determined the extent to which PNN removal prior to reinstatement altered PV intensity levels and PV cell function. Male Sprague-Dawley rats were trained for cocaine-induced conditioned place preference (CPP) followed by extinction training, microinjection of Ch-ABC in the prelimbic PFC, and cocaine-induced reinstatement. Rats were sacrificed immediately prior to reinstatement or at 2 h, 6 h, or 48 h after reinstatement for immunohistochemistry or 2 h later for electrophysiology. Our findings indicate that PNN removal only partially diminished reinstatement. Cocaine-primed reinstatement produced only minor changes in PNN or PV intensity in vehicle controls. However, after PNN removal, the intensity of remaining PNN-surrounded PV cells was decreased at all times except at 2 h post-reinstatement, at which time cocaine increased PV intensity. Consistent with this, in vehicle controls, PV neurons naturally devoid of PNNs showed a similar pattern to Ch-ABC-treated rats prior to and after cocaine reinstatement, suggesting a protective effect of PNNs on cocaine-induced changes in PV intensity. Using whole-cell patch-clamp, cocaine-primed reinstatement in Ch-ABC-treated rats decreased the number of elicited action potentials but increased excitatory synaptic transmission, which may have been compensatory. These findings suggest that without PNNs, cocaine-induced reinstatement produces rapid changes in PV intensity and PV cell excitability, which may in turn regulate output of the mPFC post-memory retrieval and diminish the maintenance of cocaine memory during reconsolidation.
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Affiliation(s)
- Angela E. Gonzalez
- Program in Integrative Physiology and Neuroscience, Washington State University, Vancouver, WA, United States
- Dow Neurobiology Laboratories, Legacy Research Institute, Portland, OR, United States
| | - Emily T. Jorgensen
- Neuroscience Graduate Program and School of Pharmacy, University of Wyoming, Laramie, WY, United States
| | - Jonathan D. Ramos
- Dow Neurobiology Laboratories, Legacy Research Institute, Portland, OR, United States
| | | | - Jake A. Aadland
- Neuroscience Graduate Program and School of Pharmacy, University of Wyoming, Laramie, WY, United States
| | - Travis E. Brown
- Neuroscience Graduate Program and School of Pharmacy, University of Wyoming, Laramie, WY, United States
| | - Barbara A. Sorg
- Program in Integrative Physiology and Neuroscience, Washington State University, Vancouver, WA, United States
- Dow Neurobiology Laboratories, Legacy Research Institute, Portland, OR, United States
- *Correspondence: Barbara A. Sorg
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Bjorness TE, Greene RW. Arousal-Mediated Sleep Disturbance Persists During Cocaine Abstinence in Male Mice. Front Neurosci 2022; 16:868049. [PMID: 35812231 PMCID: PMC9260276 DOI: 10.3389/fnins.2022.868049] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2022] [Accepted: 06/06/2022] [Indexed: 11/13/2022] Open
Abstract
Acute cocaine disturbs sleep on a dose-dependent basis; however, the consequences of chronic cocaine remain unclear. While the arousal promotion following cocaine has been well-established, effects of cocaine on sleep after termination of chronic cocaine exposure appear variable in human subjects with few studies in non-human subjects. Here, a within-subjects design (outcomes normalized to baseline, undisturbed behavior) and between-subjects design (repeated experimenter-administered cocaine vs. experimenter-administered saline) was used to investigate sleep homeostasis and sleep/waking under repeated cocaine/saline exposure and prolonged forced abstinence conditions in mice. Overall, during the forced abstinence period increases in arousal, as determined by sleep latency and gamma energy, persisted for 2 weeks. However, the sleep response to externally enforced sleep deprivation was unchanged suggesting that sleep disruptions during the forced abstinence period were driven by enhancement of arousal in the absence of changes in sleep homeostatic responses.
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Affiliation(s)
- Theresa E. Bjorness
- Research Service, Veterans Affairs (VA) North Texas Health Care System, Dallas, TX, United States
- Department of Psychiatry, Peter O’Donnell Jr. Brain Institute, University of Texas Southwestern, Dallas, TX, United States
- *Correspondence: Theresa E. Bjorness,
| | - Robert W. Greene
- Department of Psychiatry, Peter O’Donnell Jr. Brain Institute, University of Texas Southwestern, Dallas, TX, United States
- Department of Neuroscience, Peter O’Donnell Jr. Brain Institute, University of Texas Southwestern Medical Center, Dallas, TX, United States
- International Institute for Integrative Sleep Medicine, University of Tsukuba, Tsukuba, Japan
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Bjorness TE, Greene RW. Interaction between cocaine use and sleep behavior: A comprehensive review of cocaine's disrupting influence on sleep behavior and sleep disruptions influence on reward seeking. Pharmacol Biochem Behav 2021; 206:173194. [PMID: 33940055 DOI: 10.1016/j.pbb.2021.173194] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/06/2020] [Revised: 04/20/2021] [Accepted: 04/27/2021] [Indexed: 12/21/2022]
Abstract
Dopamine, orexin (hypocretin), and adenosine systems have dual roles in reward and sleep/arousal suggesting possible mechanisms whereby drugs of abuse may influence both reward and sleep/arousal. While considerable variability exists across studies, drugs of abuse such as cocaine induce an acute sleep loss followed by an immediate recovery pattern that is consistent with a normal response to loss of sleep. Under more chronic cocaine exposure conditions, an abnormal recovery pattern is expressed that includes a retention of sleep disturbance under withdrawal and into abstinence conditions. Conversely, experimentally induced sleep disturbance can increase cocaine seeking. Thus, complementary, sleep-related therapeutic approaches may deserve further consideration along with development of non-human models to better characterize sleep disturbance-reward seeking interactions across drug experience.
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Affiliation(s)
- Theresa E Bjorness
- Research Service, VA North Texas Health Care System, Dallas, TX 75126, USA; Department of Psychiatry, University of Texas Southwestern Medical Center, Dallas, TX 75390-9111, USA.
| | - Robert W Greene
- Department of Psychiatry, University of Texas Southwestern Medical Center, Dallas, TX 75390-9111, USA; Department of Neuroscience, Peter O'Donnell Jr. Brain Institute, University of Texas Southwestern Medical Center, Dallas, TX 75390-9111, USA; International Institute for Integrative Sleep Medicine, University of Tsukuba, Tsukuba, 305-8577, Japan
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Relationships between oxygen changes in the brain and periphery following physiological activation and the actions of heroin and cocaine. Sci Rep 2021; 11:6355. [PMID: 33737657 PMCID: PMC7973713 DOI: 10.1038/s41598-021-85798-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Accepted: 03/05/2021] [Indexed: 11/09/2022] Open
Abstract
Using two-sensor electrochemical recordings in freely moving rats, we examined the relationship between physiological and drug-induced oxygen fluctuations in the brain and periphery. Animals chronically implanted with oxygen sensors in the nucleus accumbens (NAc) and subcutaneous (SC) space were subjected to several mildly arousing stimuli (sound, tail-pinch and social interaction) and intravenous injections of cocaine and heroin. Arousing stimuli induced rapid increases in NAc oxygen levels followed by and correlated with oxygen decreases in the SC space. Therefore, cerebral vasodilation that increases cerebral blood flow and oxygen entry into brain tissue results from both direct neuronal activation and peripheral vasoconstriction, which redistributes arterial blood from periphery to the brain. The latter factor could also explain a similar pattern of oxygen responses found in the substantia nigra reticulata, suggesting hyperoxia as a global phenomenon with minor structural differences during early time intervals following the stimulus onset. While arousing stimuli and cocaine induced similar oxygen responses in the brain and SC space, heroin induced a biphasic down-up brain oxygen fluctuation associated with a monophasic oxygen decrease in the SC space. Oxygen decreases occurred more rapidly and stronger in the SC space, reflecting a drop in blood oxygen levels due to respiratory depression.
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Kiyatkin EA. The Critical Role of Peripheral Targets in Triggering Rapid Neural Effects of Intravenous Cocaine. Neuroscience 2020; 451:240-254. [PMID: 33010343 DOI: 10.1016/j.neuroscience.2020.09.050] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2020] [Revised: 09/18/2020] [Accepted: 09/23/2020] [Indexed: 01/23/2023]
Abstract
Direct interaction of cocaine with centrally located monoamine transporters is the primary mechanism underlying its reinforcing properties. It is also often assumed that this drug action is responsible for all the physiological and behavioral effects of this drug. The goal of this review is to challenge this basic mechanism and demonstrate the importance of peripheral actions of cocaine in inducing its initial, rapid neural effects. The use of high-resolution electrophysiological, neurochemical and physiological techniques revealed that the effects of intravenous cocaine at behaviorally relevant doses are exceptionally rapid and transient correlating with strong, quick, and transient increases in blood cocaine levels. Some of these effects are mimicked by cocaine-methiodide, a cocaine analog that cannot cross the blood-brain barrier and they are resistant to dopamine (DA) receptor blockade. Therefore, it appears that rapid neural effects of cocaine result from its direct interaction with receptive sites on afferents of sensory nerves densely innervating blood vessels. This interaction creates a rapid neural signal to the CNS that results in generalized neural activation and subsequent changes in different physiological parameters. This drug's action appears to be independent from cocaine's action on central neurons, which requires a definite time to occur and induce neural and physiological effects with longer latencies and durations. The co-existence in the same drug on two timely distinct actions with their subsequent interaction in the CNS could explain consistent changes in physiological and behavioral effects of cocaine following their repeated use, playing a role in the development of drug-seeking and drug-taking behavior.
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Affiliation(s)
- Eugene A Kiyatkin
- Behavioral Neuroscience Branch, National Institute on Drug Abuse - Intramural Research Program, National Institutes of Health, DHHS, Baltimore, MD 21224, USA.
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Abstract
Neural oscillations play an important role in the integration and segregation of brain regions that are important for brain functions, including pain. Disturbances in oscillatory activity are associated with several disease states, including chronic pain. Studies of neural oscillations related to pain have identified several functional bands, especially alpha, beta, and gamma bands, implicated in nociceptive processing. In this review, we introduce several properties of neural oscillations that are important to understand the role of brain oscillations in nociceptive processing. We also discuss the role of neural oscillations in the maintenance of efficient communication in the brain. Finally, we discuss the role of neural oscillations in healthy and chronic pain nociceptive processing. These data and concepts illustrate the key role of regional and interregional neural oscillations in nociceptive processing underlying acute and chronic pains.
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Affiliation(s)
- Junseok A. Kim
- Division of Brain, Imaging and Behaviour, Krembil Brain Institute, Krembil Research Institute, University Health Network, Toronto, Ontario, Canada
- Institute of Medical Science, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Karen D. Davis
- Division of Brain, Imaging and Behaviour, Krembil Brain Institute, Krembil Research Institute, University Health Network, Toronto, Ontario, Canada
- Institute of Medical Science, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
- Department of Surgery, University of Toronto, Toronto, Ontario, Canada
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Thomas SA, Perekopskiy D, Kiyatkin EA. Cocaine added to heroin fails to affect heroin-induced brain hypoxia. Brain Res 2020; 1746:147008. [PMID: 32645379 DOI: 10.1016/j.brainres.2020.147008] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2020] [Revised: 06/10/2020] [Accepted: 06/30/2020] [Indexed: 02/06/2023]
Abstract
Heroin and cocaine are both highly addictive drugs that cause unique physiological and behavioral effects. These drugs are often co-administered and cocaine has been found in ~20% of cases of opioid overdose death. Respiratory depression followed by brain hypoxia is the most dangerous effect of high-dose opioids that could result in coma and even death. Conversely, cocaine at optimal self-administering doses increases brain oxygen levels. Considering these differences, it is unclear what pattern of oxygen changes will occur when these drugs are co-administered. Here, we used high-speed amperometry with oxygen sensors to examine changes in oxygen concentrations in the nucleus accumbens (NAc) induced by intravenous (iv) cocaine, heroin, and their mixtures in freely-moving rats. Cocaine delivered at a range of doses, both below (0.25 mg/kg) and within the optimal range of self-administration (0.5 and 1.0 mg/kg) modestly increased NAc oxygen levels. In contrast, heroin increased oxygen levels at a low reinforcing dose (0.05 mg/kg), but induced a biphasic down-up change at higher reinforcing doses (0.1 and 0.2 mg/kg), and caused a strong monophasic oxygen decrease during overdose (0.6 mg/kg). When combined at moderate doses, cocaine (0.25, 0.5 mg/kg) slightly increased and prolonged oxygen increases induced by heroin alone (0.5 and 0.1 mg/kg), but oxygen decreases were identical when cocaine (1 mg/kg) was combined with heroin at large doses (0.2 and 0.6 mg/kg). Therefore, health dangers of speedball may result from de-compensation of vital functions due to diminished intra-brain oxygen inflow induced by high-dose heroin coupled with enhanced oxygen use induced by cocaine.
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Affiliation(s)
- Shruthi A Thomas
- Behavioral Neuroscience Branch, National Institute on Drug Abuse, Intramural Research Program, National Institutes of Health, DHHS, 251 Bayview Boulevard, Baltimore, MD 21224-6825, USA
| | - David Perekopskiy
- Behavioral Neuroscience Branch, National Institute on Drug Abuse, Intramural Research Program, National Institutes of Health, DHHS, 251 Bayview Boulevard, Baltimore, MD 21224-6825, USA
| | - Eugene A Kiyatkin
- Behavioral Neuroscience Branch, National Institute on Drug Abuse, Intramural Research Program, National Institutes of Health, DHHS, 251 Bayview Boulevard, Baltimore, MD 21224-6825, USA.
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Solis E, Afzal A, Kiyatkin EA. Intravenous Cocaine Increases Oxygen Entry into Brain Tissue: Critical Role of Peripheral Drug Actions. ACS Chem Neurosci 2019; 10:1923-1928. [PMID: 30040399 PMCID: PMC10754540 DOI: 10.1021/acschemneuro.8b00302] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Although it is well established that the direct action of cocaine on centrally located neural substrates is essential in mediating its reinforcing properties, cocaine induces very rapid immediate neural effects that imply cocaine's action on peripheral neural substrates. We employed oxygen sensors coupled with high-speed amperometery to examine the effects of standard cocaine HCl that easily enters the blood-brain barrier and its blood-brain barrier-impermeable methiodide analogue on oxygen levels in the nucleus accumbens in awake, freely moving rats. Both drugs induced strong increases in nucleus accumbens oxygen levels, which displayed similarly short, second-scale latencies and a general similarity with oxygen increases induced by an auditory stimulus. This study provides additional support for the view that the immediate neural effects of intravenous cocaine are triggered via its direct action on peripherally located neural substrates and fast neural transmission to the central nervous system via somatosensory pathways.
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Affiliation(s)
- Ernesto Solis
- In-Vivo Electrophysiology Unit, Behavioral Neuroscience Branch, National Institute on Drug Abuse – Intramural Research Program, National Institutes of Health, DHHS, 333 Cassell Drive, Baltimore, MD 21224, USA
| | - Anum Afzal
- In-Vivo Electrophysiology Unit, Behavioral Neuroscience Branch, National Institute on Drug Abuse – Intramural Research Program, National Institutes of Health, DHHS, 333 Cassell Drive, Baltimore, MD 21224, USA
| | - Eugene A. Kiyatkin
- In-Vivo Electrophysiology Unit, Behavioral Neuroscience Branch, National Institute on Drug Abuse – Intramural Research Program, National Institutes of Health, DHHS, 333 Cassell Drive, Baltimore, MD 21224, USA
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Knyazev GG, Savostyanov AN, Bocharov AV, Brak IV, Osipov EA, Filimonova EA, Saprigyn AE, Aftanas LI. Task-positive and task-negative networks in major depressive disorder: A combined fMRI and EEG study. J Affect Disord 2018; 235:211-219. [PMID: 29656269 DOI: 10.1016/j.jad.2018.04.003] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/14/2017] [Revised: 02/23/2018] [Accepted: 04/02/2018] [Indexed: 10/17/2022]
Abstract
BACKGROUND The study of intrinsic connectivity networks, i.e., sets of brain regions that show a high degree of interconnectedness even in the absence of a task, showed that major depressive disorder (MDD) patients demonstrate an increased connectivity within the default mode network (DMN), which is active in a resting state and is implicated in self-referential processing, and a decreased connectivity in task-positive networks (TPNs), which increase their activity in attention tasks. Cortical localization of this 'dominance' of the DMN over the TPN in MDD patients is not fully understood. Besides, this effect has been investigated using fMRI and its electrophysiological underpinning is not known. METHOD In this study, we tested the dominance hypothesis using seed-based connectivity analysis of resting-state fMRI and EEG data obtained in 41 MDD patients and 23 controls. RESULTS In MDD patients, as compared to controls, insula, pallidum/putamen, amygdala, and left dorso- and ventrolateral prefrontal cortex are more strongly connected with DMN than with TPN seeds. In EEG, all significant effects were obtained in the delta frequency band. LIMITATIONS fMRI and EEG data were not obtained simultaneously during the same session. CONCLUSIONS In MDD patients, major emotion and attention regulation circuits are more strongly connected with DMN than with TPN implying they are more prepared to respond to internally generated self-related thoughts than to environmental challenges.
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Affiliation(s)
- Gennady G Knyazev
- Laboratory of Psychophysiology of Individual Differences, Institute of Physiology and Basic Medicine, Novosibirsk, Russia.
| | - Alexander N Savostyanov
- Laboratory of Psychophysiology of Individual Differences, Institute of Physiology and Basic Medicine, Novosibirsk, Russia; Humanitarian Institute, Novosibirsk State University, Novosibirsk, Russia
| | - Andrey V Bocharov
- Laboratory of Psychophysiology of Individual Differences, Institute of Physiology and Basic Medicine, Novosibirsk, Russia; Humanitarian Institute, Novosibirsk State University, Novosibirsk, Russia
| | - Ivan V Brak
- Laboratory of Affective and Cognitive Neuroscience, Institute of Physiology and Basic Medicine, Novosibirsk, Russia
| | - Evgeny A Osipov
- Laboratory of Affective and Cognitive Neuroscience, Institute of Physiology and Basic Medicine, Novosibirsk, Russia
| | - Elena A Filimonova
- Laboratory of Affective and Cognitive Neuroscience, Institute of Physiology and Basic Medicine, Novosibirsk, Russia
| | - Alexander E Saprigyn
- Laboratory of Psychophysiology of Individual Differences, Institute of Physiology and Basic Medicine, Novosibirsk, Russia
| | - Lyubomir I Aftanas
- Laboratory of Affective and Cognitive Neuroscience, Institute of Physiology and Basic Medicine, Novosibirsk, Russia; Department of Neuroscience, Novosibirsk State University, Novosibirsk, Russia
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14
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Meyers JL, Zhang J, Wang JC, Su J, Kuo SI, Kapoor M, Wetherill L, Bertelsen S, Lai D, Salvatore JE, Kamarajan C, Chorlian D, Agrawal A, Almasy L, Bauer L, Bucholz KK, Chan G, Hesselbrock V, Koganti L, Kramer J, Kuperman S, Manz N, Pandey A, Seay M, Scott D, Taylor RE, Dick DM, Edenberg HJ, Goate A, Foroud T, Porjesz B. An endophenotype approach to the genetics of alcohol dependence: a genome wide association study of fast beta EEG in families of African ancestry. Mol Psychiatry 2017; 22:1767-1775. [PMID: 28070124 PMCID: PMC5503794 DOI: 10.1038/mp.2016.239] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/17/2016] [Revised: 09/24/2016] [Accepted: 10/27/2016] [Indexed: 01/16/2023]
Abstract
Fast beta (20-28 Hz) electroencephalogram (EEG) oscillatory activity may be a useful endophenotype for studying the genetics of disorders characterized by neural hyperexcitability, including substance use disorders (SUDs). However, the genetic underpinnings of fast beta EEG have not previously been studied in a population of African-American ancestry (AA). In a sample of 2382 AA individuals from 482 families drawn from the Collaborative Study on the Genetics of Alcoholism (COGA), we performed a genome-wide association study (GWAS) on resting-state fast beta EEG power. To further characterize our genetic findings, we examined the functional and clinical/behavioral significance of GWAS variants. Ten correlated single-nucleotide polymorphisms (SNPs) (r2>0.9) located in an intergenic region on chromosome 3q26 were associated with fast beta EEG power at P<5 × 10-8. The most significantly associated SNP, rs11720469 (β: -0.124; P<4.5 × 10-9), is also an expression quantitative trait locus for BCHE (butyrylcholinesterase), expressed in thalamus tissue. Four of the genome-wide SNPs were also associated with Diagnostic and Statistical Manual of Mental Disorders Alcohol Dependence in COGA AA families, and two (rs13093097, rs7428372) were replicated in an independent AA sample (Gelernter et al.). Analyses in the AA adolescent/young adult (offspring from COGA families) subsample indicated association of rs11720469 with heavy episodic drinking (frequency of consuming 5+ drinks within 24 h). Converging findings presented in this study provide support for the role of genetic variants within 3q26 in neural and behavioral disinhibition. These novel genetic findings highlight the importance of including AA populations in genetics research on SUDs and the utility of the endophenotype approach in enhancing our understanding of mechanisms underlying addiction susceptibility.
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Affiliation(s)
- J L Meyers
- Department of Psychiatry, State University of New York Downstate Medical Center, Brooklyn, NY, USA
| | - J Zhang
- Department of Psychiatry, State University of New York Downstate Medical Center, Brooklyn, NY, USA
| | - J C Wang
- Department of Neuroscience, Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - J Su
- Department of Psychology, Virginia Commonwealth University, Richmond, VA, USA
| | - S I Kuo
- Department of Psychology, Virginia Commonwealth University, Richmond, VA, USA
| | - M Kapoor
- Department of Neuroscience, Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - L Wetherill
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN, USA
| | - S Bertelsen
- Department of Neuroscience, Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - D Lai
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN, USA
| | - J E Salvatore
- Department of Psychology, Virginia Commonwealth University, Richmond, VA, USA
- Virginia Institute of Psychiatric and Behavioral Genetics, Virginia Commonwealth University, Richmond, VA, USA
| | - C Kamarajan
- Department of Psychiatry, State University of New York Downstate Medical Center, Brooklyn, NY, USA
| | - D Chorlian
- Department of Psychiatry, State University of New York Downstate Medical Center, Brooklyn, NY, USA
| | - A Agrawal
- Department of Psychiatry, Washington University School of Medicine in St Louis, St Louis, MO, USA
| | - L Almasy
- Department of Biomedical and Health Informatics, The Children's Hospital of Philadelphia, Philadelphia, PA, USA
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - L Bauer
- Department of Psychiatry, University of Connecticut School of Medicine, Farmington, CT, USA
| | - K K Bucholz
- Department of Psychiatry, Washington University School of Medicine in St Louis, St Louis, MO, USA
| | - G Chan
- Department of Psychiatry, University of Connecticut School of Medicine, Farmington, CT, USA
| | - V Hesselbrock
- Department of Psychiatry, University of Connecticut School of Medicine, Farmington, CT, USA
| | - L Koganti
- Department of Neuroscience, Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - J Kramer
- Department of Psychiatry, University of Iowa Carver College of Medicine, Iowa City, IA, USA
| | - S Kuperman
- Department of Psychiatry, University of Iowa Carver College of Medicine, Iowa City, IA, USA
| | - N Manz
- Department of Physics, The College of Wooster, Wooster, OH, USA
| | - A Pandey
- Department of Psychiatry, State University of New York Downstate Medical Center, Brooklyn, NY, USA
| | - M Seay
- Department of Psychiatry, State University of New York Downstate Medical Center, Brooklyn, NY, USA
| | - D Scott
- Collaborative Alcohol Research Center, Howard University College of Medicine, Washington, DC, USA
| | - R E Taylor
- Collaborative Alcohol Research Center, Howard University College of Medicine, Washington, DC, USA
| | - D M Dick
- Department of Psychology, Virginia Commonwealth University, Richmond, VA, USA
- Virginia Institute of Psychiatric and Behavioral Genetics, Virginia Commonwealth University, Richmond, VA, USA
| | - H J Edenberg
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN, USA
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN, USA
| | - A Goate
- Department of Neuroscience, Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, USA
- Department of Neurology, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - T Foroud
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN, USA
| | - B Porjesz
- Department of Psychiatry, State University of New York Downstate Medical Center, Brooklyn, NY, USA
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15
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Bola RA, Kiyatkin EA. Inflow of oxygen and glucose in brain tissue induced by intravenous norepinephrine: relationships with central metabolic and peripheral vascular responses. J Neurophysiol 2017; 119:499-508. [PMID: 29118201 DOI: 10.1152/jn.00692.2017] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
As an essential part of sympathetic activation that prepares the organism for "fight or flight," peripheral norepinephrine (NE) plays an important role in regulating cardiac activity and the tone of blood vessels, increasing blood flow to the heart and the brain and decreasing blood flow to the organs not as necessary for immediate survival. To assess whether this effect is applicable to the brain, we used high-speed amperometry to measure the changes in nucleus accumbens (NAc) levels of oxygen and glucose induced by intravenous injections of NE in awake freely moving rats. We found that NE at low doses (2-18 μg/kg) induces correlative increases in NAc oxygen and glucose, suggesting local vasodilation and enhanced entry of these substances in brain tissue from the arterial blood. By using temperature recordings from the NAc, temporal muscle, and skin, we show that this central effect is associated with strong skin vasoconstriction and phasic increases in intrabrain heat production, indicative of metabolic neural activation. A tight direct correlation between NE-induced changes in metabolic activity and NAc levels of oxygen and glucose levels suggests that local cerebral vasodilation is triggered via a neurovascular coupling mechanism. Our data suggest that NE, by changing vascular tone and cardiac activity, triggers a visceral sensory signal that rapidly reaches the central nervous system via sensory nerves and induces neural activation. This neural activation leads to a chain of neurovascular events that promote entry of oxygen and glucose in brain tissue, thus preventing any possible metabolic deficit during functional activation. NEW & NOTEWORTHY Using high-speed amperometry and thermorecording in freely moving rats, we demonstrate that intravenous norepinephrine at physiological doses induces rapid correlative increases in nucleus accumbens oxygen and glucose levels coupled with increased intrabrain heat production. Although norepinephrine cannot cross the blood-brain barrier, by changing cardiac activity and vascular tone, it creates a sensory signal that reaches the central nervous system via sensory nerves, induces neural activation, and triggers a chain of neurovascular events that promotes intrabrain entry of oxygen and glucose.
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Affiliation(s)
- R Aaron Bola
- Behavioral Neuroscience Branch, National Institute on Drug Abuse-Intramural Research Program, National Institutes of Health, Baltimore, Maryland
| | - Eugene A Kiyatkin
- Behavioral Neuroscience Branch, National Institute on Drug Abuse-Intramural Research Program, National Institutes of Health, Baltimore, Maryland
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16
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Solis E, Cameron-Burr KT, Kiyatkin EA. Rapid Physiological Fluctuations in Nucleus Accumbens Oxygen Levels Induced by Arousing Stimuli: Relationships with Changes in Brain Glucose and Metabolic Neural Activation. Front Integr Neurosci 2017; 11:9. [PMID: 28484378 PMCID: PMC5401908 DOI: 10.3389/fnint.2017.00009] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2017] [Accepted: 04/06/2017] [Indexed: 01/01/2023] Open
Abstract
Proper entry of oxygen from arterial blood into the brain is essential for maintaining brain metabolism under normal conditions and during functional neural activation. However, little is known about physiological fluctuations in brain oxygen and their underlying mechanisms. To address this issue, we employed high-speed amperometry with platinum oxygen sensors in freely moving male rats. Recordings were conducted in the nucleus accumbens (NAc), a critical structure for sensorimotor integration. Rats were exposed to arousing stimuli of different nature (brief auditory tone, a 1-min novel object presentation, a 3-min social interaction with a conspecific, and a 3-min tail-pinch). We found that all arousing stimuli increased NAc oxygen levels. Increases were rapid (4–10-s onset latencies), modest in magnitude (1–3 μM or 5%–15% over baseline) and duration (5–20 min), and generally correlated with the arousing potential of each stimulus. Two strategies were used to determine the mechanisms underlying the observed increases in NAc oxygen levels. First, we showed that NAc oxygen levels phasically increase following intra-NAc microinjections of glutamate (GLU) that excite accumbal neurons. Therefore, local neural activation with subsequent local vasodilation is involved in mediating physiological increases in NAc oxygen induced by arousing stimuli. Second, by employing oxygen monitoring in the subcutaneous space, a highly-vascularized area with no metabolic activity, we determined that physiological increases in NAc oxygen also depend on the rise in blood oxygen levels caused by respiratory activation. Due to the co-existence of different mechanisms governing oxygen entry into brain tissue, NAc oxygen responses differ from fluctuations in NAc glucose, which, within a normal behavioral continuum, are regulated exclusively by neuro-vascular coupling due to glucose’s highly stable levels in the blood. Finally, we discuss the relationships between physiological fluctuations in NAc oxygen, glucose and metabolic brain activation assessed by intra-brain heat production.
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Affiliation(s)
- Ernesto Solis
- In-Vivo Electrophysiology Unit, Behavioral Neuroscience Branch, National Institute on Drug Abuse-Intramural Research Program, Department of Health and Human Services, National Institutes of HealthBaltimore, MD, USA
| | - Keaton T Cameron-Burr
- In-Vivo Electrophysiology Unit, Behavioral Neuroscience Branch, National Institute on Drug Abuse-Intramural Research Program, Department of Health and Human Services, National Institutes of HealthBaltimore, MD, USA
| | - Eugene A Kiyatkin
- In-Vivo Electrophysiology Unit, Behavioral Neuroscience Branch, National Institute on Drug Abuse-Intramural Research Program, Department of Health and Human Services, National Institutes of HealthBaltimore, MD, USA
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17
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Wakabayashi KT, Ren SE, Kiyatkin EA. Methylenedioxypyrovalerone (MDPV) mimics cocaine in its physiological and behavioral effects but induces distinct changes in NAc glucose. Front Neurosci 2015; 9:324. [PMID: 26441499 PMCID: PMC4584974 DOI: 10.3389/fnins.2015.00324] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2015] [Accepted: 08/31/2015] [Indexed: 11/17/2022] Open
Abstract
Methylenedioxypyrovalerone (MDPV) is generally considered to be a more potent cocaine-like psychostimulant, as it shares a similar pharmacological profile with cocaine and induces similar physiological and locomotor responses. Recently, we showed that intravenous cocaine induces rapid rise in nucleus accumbens (NAc) glucose and established its relation to neural activation triggered by the peripheral drug actions. This study was conducted to find out whether MDPV, at a behaviorally equivalent dose, shares a similar pattern of NAc glucose dynamics. Using enzyme-based glucose sensors coupled with amperometery in freely moving rats, we found that MDPV tonically decreases NAc glucose levels, a response that is opposite to what we previously observed with cocaine. By analyzing Skin-Muscle temperature differentials, a valid measure of skin vascular tone, we found that MDPV induces vasoconstriction; a similar effect at the level of cerebral vessels could be responsible for the MDPV-induced decrease in NAc glucose. While cocaine also induced comparable, if not slightly stronger peripheral vasoconstriction, this effect was overpowered by local neural activity-induced vasodilation, resulting in rapid surge in NAc glucose. These results imply that cocaine-users may be more susceptible to addiction than MDPV-users due to the presence of an interoceptive signal (i.e., sensory cue), which may result in earlier and more direct reward detection. Additionally, while health complications arising from acute cocaine use are typically cardiovascular related, MDPV may be more dangerous to the brain due to uncompensated cerebral vasoconstriction.
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Affiliation(s)
- Ken T Wakabayashi
- In-Vivo Electrophysiology Unit, Behavioral Neuroscience Branch, National Institute on Drug Abuse - Intramural Research Program, Department of Health and Human Services, National Institutes of Health Baltimore, MD, USA
| | - Suelynn E Ren
- In-Vivo Electrophysiology Unit, Behavioral Neuroscience Branch, National Institute on Drug Abuse - Intramural Research Program, Department of Health and Human Services, National Institutes of Health Baltimore, MD, USA
| | - Eugene A Kiyatkin
- In-Vivo Electrophysiology Unit, Behavioral Neuroscience Branch, National Institute on Drug Abuse - Intramural Research Program, Department of Health and Human Services, National Institutes of Health Baltimore, MD, USA
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18
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Cannabidiol rescues acute hepatic toxicity and seizure induced by cocaine. Mediators Inflamm 2015; 2015:523418. [PMID: 25999668 PMCID: PMC4427116 DOI: 10.1155/2015/523418] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2015] [Accepted: 04/07/2015] [Indexed: 12/17/2022] Open
Abstract
Cocaine is a commonly abused illicit drug that causes significant morbidity and mortality. The most severe and common complications are seizures, ischemic strokes, myocardial infarction, and acute liver injury. Here, we demonstrated that acute cocaine intoxication promoted seizure along with acute liver damage in mice, with intense inflammatory infiltrate. Considering the protective role of the endocannabinoid system against cell toxicity, we hypothesized that treatment with an anandamide hydrolysis inhibitor, URB597, or with a phytocannabinoid, cannabidiol (CBD), protects against cocaine toxicity. URB597 (1.0 mg/kg) abolished cocaine-induced seizure, yet it did not protect against acute liver injury. Using confocal liver intravital microscopy, we observed that CBD (30 mg/kg) reduced acute liver inflammation and damage induced by cocaine and prevented associated seizure. Additionally, we showed that previous liver damage induced by another hepatotoxic drug (acetaminophen) increased seizure and lethality induced by cocaine intoxication, linking hepatotoxicity to seizure dynamics. These findings suggest that activation of cannabinoid system may have protective actions on both liver and brain induced by cocaine, minimizing inflammatory injury promoted by cocaine, supporting its further clinical application in the treatment of cocaine abuse.
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19
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A subpopulation of neurochemically-identified ventral tegmental area dopamine neurons is excited by intravenous cocaine. J Neurosci 2015; 35:1965-78. [PMID: 25653355 DOI: 10.1523/jneurosci.3422-13.2015] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Systemic administration of cocaine is thought to decrease the firing rates of ventral tegmental area (VTA) dopamine (DA) neurons. However, this view is based on categorizations of recorded neurons as DA neurons using preselected electrophysiological characteristics lacking neurochemical confirmation. Without applying cellular preselection, we recorded the impulse activity of VTA neurons in response to cocaine administration in anesthetized adult rats. The phenotype of recorded neurons was determined by their juxtacellular labeling and immunohistochemical detection of tyrosine hydroxylase (TH), a DA marker. We found that intravenous cocaine altered firing rates in the majority of recorded VTA neurons. Within the cocaine-responsive neurons, half of the population was excited and the other half was inhibited. Both populations had similar discharge rates and firing regularities, and most neurons did not exhibit changes in burst firing. Inhibited neurons were more abundant in the posterior VTA, whereas excited neurons were distributed evenly throughout the VTA. Cocaine-excited neurons were more likely to be excited by footshock. Within the subpopulation of TH-positive neurons, 36% were excited by cocaine and 64% were inhibited. Within the subpopulation of TH-negative neurons, 44% were excited and 28% were inhibited. Contrary to the prevailing view that all DA neurons are inhibited by cocaine, we found a subset of confirmed VTA DA neurons that is excited by systemic administration of cocaine. We provide evidence indicating that DA neurons are heterogeneous in their response to cocaine and that VTA non-DA neurons play an active role in processing systemic cocaine.
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20
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Wakabayashi KT, Kiyatkin EA. Central and peripheral contributions to dynamic changes in nucleus accumbens glucose induced by intravenous cocaine. Front Neurosci 2015; 9:42. [PMID: 25729349 PMCID: PMC4325903 DOI: 10.3389/fnins.2015.00042] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2014] [Accepted: 01/29/2015] [Indexed: 12/13/2022] Open
Abstract
The pattern of neural, physiological and behavioral effects induced by cocaine is consistent with metabolic neural activation, yet direct attempts to evaluate central metabolic effects of this drug have produced controversial results. Here, we used enzyme-based glucose sensors coupled with high-speed amperometry in freely moving rats to examine how intravenous cocaine at a behaviorally active dose affects extracellular glucose levels in the nucleus accumbens (NAc), a critical structure within the motivation-reinforcement circuit. In drug-naive rats, cocaine induced a bimodal increase in glucose, with the first, ultra-fast phasic rise appearing during the injection (latency 6–8 s; ~50 μM or ~5% of baseline) followed by a larger, more prolonged tonic elevation (~100 μM or 10% of baseline, peak ~15 min). While the rapid, phasic component of the glucose response remained stable following subsequent cocaine injections, the tonic component progressively decreased. Cocaine-methiodide, cocaine's peripherally acting analog, induced an equally rapid and strong initial glucose rise, indicating cocaine's action on peripheral neural substrates as its cause. However, this analog did not induce increases in either locomotion or tonic glucose, suggesting direct central mediation of these cocaine effects. Under systemic pharmacological blockade of dopamine transmission, both phasic and tonic components of the cocaine-induced glucose response were only slightly reduced, suggesting a significant role of non-dopamine mechanisms in cocaine-induced accumbal glucose influx. Hence, intravenous cocaine induces rapid, strong inflow of glucose into NAc extracellular space by involving both peripheral and central, non-dopamine drug actions, thus preventing a possible deficit resulting from enhanced glucose use by brain cells.
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Affiliation(s)
- Ken T Wakabayashi
- Behavioral Neuroscience Branch, National Institute on Drug Abuse - Intramural Research Program, National Institutes of Health, DHHS Baltimore, MD, USA
| | - Eugene A Kiyatkin
- Behavioral Neuroscience Branch, National Institute on Drug Abuse - Intramural Research Program, National Institutes of Health, DHHS Baltimore, MD, USA
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21
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Kiyatkin EA, Wakabayashi KT. Parsing glucose entry into the brain: novel findings obtained with enzyme-based glucose biosensors. ACS Chem Neurosci 2015; 6:108-16. [PMID: 25490002 PMCID: PMC4304521 DOI: 10.1021/cn5002304] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
![]()
Extracellular levels of glucose in
brain tissue reflect dynamic
balance between its gradient-dependent entry from arterial blood and
its use for cellular metabolism. In this work, we present several
sets of previously published and unpublished data obtained by using
enzyme-based glucose biosensors coupled with constant-potential high-speed
amperometry in freely moving rats. First, we consider basic methodological
issues related to the reliability of electrochemical measurements
of extracellular glucose levels in rats under physiologically relevant
conditions. Second, we present data on glucose responses induced in
the nucleus accumbens (NAc) by salient environmental stimuli and discuss
the relationships between local neuronal activation and rapid glucose
entry into brain tissue. Third, by presenting data on changes in NAc
glucose induced by intravenous and intragastric glucose delivery,
we discuss other mechanisms of glucose entry into the extracellular
domain following changes in glucose blood concentrations. Lastly,
by showing the pattern of NAc glucose fluctuations during glucose-drinking
behavior, we discuss the relationships between “active”
and “passive” glucose entry to the brain, its connection
to behavior-related metabolic activation, and the possible functional
significance of these changes in behavioral regulation. These data
provide solid experimental support for the “neuronal”
hypothesis of neurovascular coupling, which postulates the critical
role of neuronal activity in rapid regulation of vascular tone, local
blood flow, and entry of glucose and oxygen to brain tissue to maintain
active cellular metabolism.
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Affiliation(s)
- Eugene A. Kiyatkin
- In-Vivo
Electrophysiology
Unit, Behavioral Neuroscience Branch, National Institute on Drug Abuse
− Intramural Research Program, National Institutes of Health, DHHS, 333 Cassell Drive, Baltimore, Maryland 21224, United States
| | - Ken T. Wakabayashi
- In-Vivo
Electrophysiology
Unit, Behavioral Neuroscience Branch, National Institute on Drug Abuse
− Intramural Research Program, National Institutes of Health, DHHS, 333 Cassell Drive, Baltimore, Maryland 21224, United States
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22
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Wakabayashi KT, Myal SE, Kiyatkin EA. Fluctuations in nucleus accumbens extracellular glutamate and glucose during motivated glucose-drinking behavior: dissecting the neurochemistry of reward. J Neurochem 2015; 132:327-41. [PMID: 25393775 DOI: 10.1111/jnc.12993] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2014] [Revised: 10/17/2014] [Accepted: 11/10/2014] [Indexed: 12/21/2022]
Abstract
While motivated behavior involves multiple neurochemical systems, few studies have focused on the role of glutamate, the brain's excitatory neurotransmitter, and glucose, the energetic substrate of neural activity in reward-related neural processes. Here, we used high-speed amperometry with enzyme-based substrate-sensitive and control, enzyme-free biosensors to examine second-scale fluctuations in the extracellular levels of these substances in the nucleus accumbens shell during glucose-drinking behavior in trained rats. Glutamate rose rapidly after the presentation of a glucose-containing cup and before the initiation of drinking (reward seeking), decreased more slowly to levels below baseline during consumption (sensory reward), and returned to baseline when the ingested glucose reached the brain (metabolic reward). When water was substituted for glucose, glutamate rapidly increased with cup presentation and in contrast to glucose drinking, increased above baseline after rats tasted the water and refused to drink further. Therefore, extracellular glutamate show distinct changes associated with key events of motivated drinking behavior and opposite dynamics during sensory and metabolic components of reward. In contrast to glutamate, glucose increased at each stimulus and behavioral event, showing a sustained elevation during the entire behavior and a robust post-ingestion rise that correlated with the gradual return of glutamate levels to their baseline. By comparing active drinking with passive intra-gastric glucose delivery, we revealed that fluctuations in extracellular glucose are highly dynamic, reflecting a balance between rapid delivery because of neural activity, intense metabolism, and the influence of ingested glucose reaching the brain.
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Affiliation(s)
- Ken T Wakabayashi
- In-Vivo Electrophysiology Unit, Behavioral Neuroscience Branch, National Institute on Drug Abuse - Intramural Research Program, National Institutes of Health, DHHS, Baltimore, Maryland, USA
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Kiyatkin EA. Critical role of peripheral sensory systems in mediating the neural effects of nicotine following its acute and repeated exposure. Rev Neurosci 2014; 25:207-21. [PMID: 24535300 DOI: 10.1515/revneuro-2013-0067] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2013] [Accepted: 01/17/2014] [Indexed: 11/15/2022]
Abstract
It is well established that the reinforcing properties of nicotine (NIC) depend on its action on nicotinic acetylcholine receptors expressed by brain neurons. However, when administered systemically, NIC first phasically activates nicotinic receptors located on the afferents of sensory nerves at the sites of drug administration before reaching the brain and directly interacting with central neurons. While this peripheral action of NIC has been known for years, it is usually neglected in any consideration of the drug's reinforcing properties and experience-dependent changes of its behavioral and physiological effects. The goal of this work was to review our recent behavioral, electrophysiological, and physiological data suggesting the critical importance of peripheral actions of NIC in mediating its neural effects following acute drug exposure and their involvement in alterations of NIC effects consistently occurring following repeated drug exposure. Because NIC, by acting peripherally, produces a rapid sensory signal to the central nervous system that is followed by slower, more prolonged direct drug actions in the brain, these two pharmacological actions interact in the central nervous system during repeated drug use with the development of Pavlovian conditioned association. This within-drug conditioning mechanism could explain the experience-dependent changes in the physiological, behavioral, and human psychoemotional effects of NIC, which, in drug-experienced individuals, always represent a combination of pharmacological and learning variables.
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Wakabayashi KT, Kiyatkin EA. Critical role of peripheral drug actions in experience-dependent changes in nucleus accumbens glutamate release induced by intravenous cocaine. J Neurochem 2013; 128:672-85. [PMID: 24111505 DOI: 10.1111/jnc.12472] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2013] [Revised: 09/26/2013] [Accepted: 09/27/2013] [Indexed: 11/28/2022]
Abstract
Recent studies reveal that cocaine experience results in persistent neuroadaptive changes within glutamate (Glu) synapses in brain areas associated with drug reward. However, it remains unclear whether cocaine affects Glu release in drug-naive animals and how it is altered by drug experience. Using high-speed amperometry with enzyme-based and enzyme-free biosensors in freely moving rats, we show that an initial intravenous cocaine injection at a low self-administering dose (1 mg/kg) induces rapid, small and transient Glu release in the nucleus accumbens shell (NAc), which with subsequent injections rapidly becomes a much stronger, two-component increase. Using cocaine-methiodide, cocaine's analog that does not cross the blood-brain barrier, we confirm that the initial cocaine-induced Glu release in the NAc has a peripheral neural origin. Unlike cocaine, Glu responses induced by cocaine-methiodide rapidly habituate following repeated exposure. However, after cocaine experience this drug induces cocaine-like Glu responses. Hence, the interoceptive actions of cocaine, which essentially precede its direct actions in the brain, play a critical role in experience-dependent alterations in Glu release, cocaine-induced neural sensitization and may contribute to cocaine addiction. Using high-speed amperometry with enzyme-based biosensors in freely moving rats, we show that initial intravenous cocaine induces rapid, transient glutamate (Glu) release in the Nac (Nucleus accumbens), rapidly becoming a stronger, two-component increase with subsequent injections. We show that the peripheral actions of cocaine, which precedes its direct central actions, play a critical role in experience-dependent alterations in Glu release, possibly contributing to cocaine addiction.
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Affiliation(s)
- Ken T Wakabayashi
- In-Vivo Electrophysiology Unit, Behavioral Neuroscience Branch, National Institute on Drug Abuse - Intramural Research Program, National Institutes of Health, DHHS, Baltimore, Maryland, USA
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Rapid sensitization of physiological, neuronal, and locomotor effects of nicotine: critical role of peripheral drug actions. J Neurosci 2013; 33:9937-49. [PMID: 23761889 DOI: 10.1523/jneurosci.4940-12.2013] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Repeated exposure to nicotine and other psychostimulant drugs produces persistent increases in their psychomotor and physiological effects (sensitization), a phenomenon related to the drugs' reinforcing properties and abuse potential. Here we examined the role of peripheral actions of nicotine in nicotine-induced sensitization of centrally mediated physiological parameters (brain, muscle, and skin temperatures), cortical and VTA EEG, neck EMG activity, and locomotion in freely moving rats. Repeated injections of intravenous nicotine (30 μg/kg) induced sensitization of the drug's effects on all these measures. In contrast, repeated injections of the peripherally acting analog of nicotine, nicotine pyrrolidine methiodide (nicotine(PM), 30 μg/kg, i.v.) resulted in habituation (tolerance) of the same physiological, neuronal, and behavioral measures. However, after repeated nicotine exposure, acute nicotine(PM) injections induced nicotine-like physiological responses: powerful cortical and VTA EEG desynchronization, EMG activation, a large brain temperature increase, but weaker hyperlocomotion. Additionally, both the acute locomotor response to nicotine and nicotine-induced locomotor sensitization were attenuated by blockade of peripheral nicotinic receptors by hexamethonium (3 mg/kg, i.v.). These data suggest that the peripheral actions of nicotine, which precede its direct central actions, serve as a conditioned interoceptive cue capable of eliciting nicotine-like physiological and neural responses after repeated nicotine exposure. Thus, by providing a neural signal to the CNS that is repeatedly paired with the direct central effects of nicotine, the drug's peripheral actions play a critical role in the development of nicotine-induced physiological, neural, and behavioral sensitization.
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Kiyatkin EA, Lenoir M. Rapid fluctuations in extracellular brain glucose levels induced by natural arousing stimuli and intravenous cocaine: fueling the brain during neural activation. J Neurophysiol 2012; 108:1669-84. [PMID: 22723672 DOI: 10.1152/jn.00521.2012] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Glucose, a primary energetic substrate for neural activity, is continuously influenced by two opposing forces that tend to either decrease its extracellular levels due to enhanced utilization in neural cells or increase its levels due to entry from peripheral circulation via enhanced cerebral blood flow. How this balance is maintained under physiological conditions and changed during neural activation remains unclear. To clarify this issue, enzyme-based glucose sensors coupled with high-speed amperometry were used in freely moving rats to evaluate fluctuations in extracellular glucose levels induced by brief audio stimulus, tail pinch (TP), social interaction with another rat (SI), and intravenous cocaine (1 mg/kg). Measurements were performed in nucleus accumbens (NAcc) and substantia nigra pars reticulata (SNr), which drastically differ in neuronal activity. In NAcc, where most cells are powerfully excited after salient stimulation, glucose levels rapidly (latency 2-6 s) increased (30-70 μM or 6-14% over baseline) by all stimuli; the increase differed in magnitude and duration for each stimulus. In SNr, where most cells are transiently inhibited by salient stimuli, TP, SI, and cocaine induced a biphasic glucose response, with the initial decrease (-20-40 μM or 5-10% below baseline) followed by a reboundlike increase. The critical role of neuronal activity in mediating the initial glucose response was confirmed by monitoring glucose currents after local microinjections of glutamate (GLU) or procaine (PRO). While intra-NAcc injection of GLU transiently increased glucose levels in this structure, intra-SNr PRO injection resulted in rapid, transient decreases in SNr glucose. Therefore, extracellular glucose levels in the brain change very rapidly after physiological and pharmacological stimulation, the response is structure specific, and the pattern of neuronal activity appears to be a critical factor determining direction and magnitude of physiological fluctuations in glucose levels.
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Affiliation(s)
- Eugene A Kiyatkin
- In-Vivo Electrophysiology Unit, Behavioral Neuroscience Branch, National Institute on Drug Abuse-Intramural Research Program, NIH, DHHS, 333 Cassell Dr., Baltimore, MD 21224, USA.
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Wakabayashi KT, Kiyatkin EA. Rapid changes in extracellular glutamate induced by natural arousing stimuli and intravenous cocaine in the nucleus accumbens shell and core. J Neurophysiol 2012; 108:285-99. [PMID: 22496525 DOI: 10.1152/jn.01167.2011] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Glutamate (Glu) is a major excitatory neurotransmitter, playing a crucial role in the functioning of the nucleus accumbens (NAc), a critical area implicated in somatosensory integration and regulation of motivated behavior. In this study, high-speed amperometry with enzyme-based biosensors was used in freely moving rats to examine changes in extracellular Glu in the NAc shell and core induced by a tone, tail pinch (TP), social interaction with a male conspecific (SI), and intravenous (iv) cocaine (1 mg/kg). To establish the contribution of Glu to electrochemical signal changes, similar recordings were conducted with null (Glu(0)) sensors, which were exposed to the same chemical and physical environment but were insensitive to Glu. TP, SI, and cocaine, but not a tone, induced relatively large and prolonged current increases detected by both Glu and Glu(0) sensors. However, current differentials revealed very rapid, much smaller, and transient increases in extracellular Glu levels, more predominantly in the NAc shell than core. In contrast to monophasic responses with natural stimuli, cocaine induced a biphasic Glu increase in the shell, with a transient peak during the injection and a slower postinjection peak. Therefore, Glu is phasically released in the NAc after exposure to natural arousing stimuli and cocaine; this release is rapid, stimulus dependent, and structure specific, suggesting its role in triggering neural and behavioral activation induced by these stimuli. This study also demonstrates the need for multiple in vitro and in vivo controls to reveal relatively small, highly phasic, and transient fluctuations in Glu levels occurring under behaviorally relevant conditions.
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Affiliation(s)
- Ken T Wakabayashi
- In-Vivo Electrophysiology Unit, Behavioral Neuroscience Branch, National Institute on Drug Abuse-Intramural Research Program, National Institutes of Health, Baltimore, MD 21224, USA
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Mejías-Aponte CA, Kiyatkin EA. Ventral tegmental area neurons are either excited or inhibited by cocaine's actions in the peripheral nervous system. Neuroscience 2012; 207:182-97. [PMID: 22300980 DOI: 10.1016/j.neuroscience.2012.01.026] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2011] [Revised: 01/10/2012] [Accepted: 01/11/2012] [Indexed: 01/13/2023]
Abstract
Cocaine's multiple pharmacological substrates are ubiquitously present in the peripheral and central nervous system. Thus, upon its administration, cocaine acts in the periphery before directly acting in the brain. We determined whether cocaine alters ventral tegmental area (VTA) neuronal activity via its peripheral actions. In urethane-anesthetized rats, we recorded VTA neuron's responses to intravenous injections of two cocaine analogs: cocaine-hydrochloride (HCl, 0.25 mg/kg), which readily cross the blood-brain barrier (BBB), and cocaine-methiodide (MI, 0.33 mg/kg), which does not cross the BBB. Both cocaine analogs produced sustained changes in discharge rates that began 5 s after the initiation of a 10-s drug infusion. Within the first 90 s post-injection, the magnitudes of neuronal responsiveness of both cocaine analogs were comparable, but later the effects of cocaine-HCl were stronger and persisted longer than those of cocaine-MI. The proportion of neurons responsive to cocaine-HCl was twice that of cocaine-MI (74% and 35%, respectively). Both analogs also differed in their response onsets. Cocaine-MI rarely evoked responses after 1 min, whereas cocaine-HCl continued to evoke responses within 3 min post-injection. VTA neurons were either excited or inhibited by both cocaine analogs. Most units responsive to cocaine-MI, regardless of whether they were excited or inhibited, had electrophysiological characteristics of putative dopamine (DA) neurons. Units inhibited by cocaine-HCl also had characteristics of DA neurons, whereas excited neurons had widely varying action potential durations and discharge rates. Cocaine-MI and cocaine-HCl each produced changes in VTA neuron activity under full DA receptor blockade. However, the duration of inhibition was shortened and the number of excitations increased, and they occurred with an earlier onset during DA receptor blockade. These findings indicate that cocaine acts peripherally with a short latency and alters the activity of VTA neurons before its well-known direct actions in the brain.
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Affiliation(s)
- C A Mejías-Aponte
- Behavioral Neuroscience Branch, Intramural Research Program, National Institute on Drug Abuse, NIH/DHHS, Triad Technology Center Suite 2200, 333 Cassell Dr., Baltimore, MD 21224, USA.
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EEG delta oscillations as a correlate of basic homeostatic and motivational processes. Neurosci Biobehav Rev 2011; 36:677-95. [PMID: 22020231 DOI: 10.1016/j.neubiorev.2011.10.002] [Citation(s) in RCA: 401] [Impact Index Per Article: 30.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2011] [Revised: 09/23/2011] [Accepted: 10/08/2011] [Indexed: 10/16/2022]
Abstract
Functional significance of delta oscillations is not fully understood. One way to approach this question would be from an evolutionary perspective. Delta oscillations dominate the EEG of waking reptiles. In humans, they are prominent only in early developmental stages and during slow-wave sleep. Increase of delta power has been documented in a wide array of developmental disorders and pathological conditions. Considerable evidence on the association between delta waves and autonomic and metabolic processes hints that they may be involved in integration of cerebral activity with homeostatic processes. Much evidence suggests the involvement of delta oscillations in motivation. They increase during hunger, sexual arousal, and in substance users. They also increase during panic attacks and sustained pain. In cognitive domain, they are implicated in attention, salience detection, and subliminal perception. This evidence shows that delta oscillations are associated with evolutionary old basic processes, which in waking adults are overshadowed by more advanced processes associated with higher frequency oscillations. The former processes rise in activity, however, when the latter are dysfunctional.
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Kiyatkin EA, Lenoir M. Intravenous saline injection as an interoceptive signal in rats. Psychopharmacology (Berl) 2011; 217:387-96. [PMID: 21494787 PMCID: PMC3377945 DOI: 10.1007/s00213-011-2294-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/31/2011] [Accepted: 03/28/2011] [Indexed: 10/18/2022]
Abstract
RATIONALE Addictive drugs are commonly delivered in the organism by means of intravenous (i.v.) injections. Since saline mimics the blood environment by basic ionic properties and pH, it is generally assumed that it should not have any physiological effects, serving as a control for the effects induced by drugs. OBJECTIVE The aim of the study was to examine central, behavioral, and physiological effects of stress- and cue-free i.v. saline injection in freely moving rats. METHODS We examined how a typical low-volume and slow-speed saline injections affect cortical electroencephalograpy (EEG), neck electromyography (EMG), locomotor activity as well as central and peripheral temperatures. RESULTS Saline injection made during slow-wave synchronized activity induces rapid transient EEG desynchronization, manifesting as a drop of EEG total power, decrease in alpha activity, and increases in beta and gamma activities. Saline injection did not affect locomotor activity as well as brain and body temperatures, but induced a transient increase in neck EMG activity and a rapid brief drop in skin temperature, suggesting peripheral vasoconstriction. These responses were virtually fully absent when saline injection was made during naturally occurring desynchronized EEG activity during behavioral activity. CONCLUSIONS Since i.v. injection is able to produce a peripheral sensory signal that is transmitted rapidly to the CNS and followed by a more prolonged effect of the injected drug on brain cells, with repeated drug administrations, the injection itself could play a role of drug-related sensory cue, thus inducing conditioned physiological responses and altering the effects of injected drugs.
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Affiliation(s)
- Eugene A Kiyatkin
- Behavioral Neuroscience Branch, National Institute on Drug Abuse, Intramural Research Program, National Institutes of Health, DHHS, 333 Cassell Drive, Baltimore, MD 21224, USA.
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Abstract
In addition to its direct action on central neurons, nicotine (NIC) activates multiple nicotinic acetylcholine receptors localized on afferent terminals of sensory nerves at the sites of its administration. Although the activation of these receptors is important in mediating the primary sensory and cardiovascular effects of NIC, their role in triggering and maintaining the neural effects of NIC remains unclear. Using high-speed electroencephalography (EEG) and electromyography (EMG) recordings in freely moving rats, we showed that NIC at low intravenous (i.v.) doses (10-30 μg/kg) induced rapid, strong, and prolonged EEG desynchronization both in the cortex and ventral tegmental area (with decreases in α and robust increases in β and γ frequencies) and neck EMG activation that began during the injection (∼5 s). EEG and EMG effects of NIC were drastically reduced by pre-treatment with hexamethonium, a peripherally acting NIC antagonist, and the immediate EEG effects of NIC were strongly inhibited during urethane anesthesia. Although NIC pyrrolidine methiodide, a quaternary NIC analog that cannot enter the brain, also induced rapid EEG desynchronization, its effects were much shorter and weaker than those of NIC. Therefore, NIC by acting on peripheral nicotinic receptors provides a major contribution to its rapid, excitatory effects following i.v. administration. Since this action creates a sensory signal that rapidly reaches the brain via neural pathways and precedes the slower and more prolonged direct actions of NIC on brain cells, it could have a major role in associative learning and changes in the behavioral and physiological effects of NIC following its repeated use.
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