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Lubejko ST, Livrizzi G, Buczynski SA, Patel J, Yung JC, Yaksh TL, Banghart MR. Inputs to the locus coeruleus from the periaqueductal gray and rostroventral medulla shape opioid-mediated descending pain modulation. SCIENCE ADVANCES 2024; 10:eadj9581. [PMID: 38669335 PMCID: PMC11051679 DOI: 10.1126/sciadv.adj9581] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/25/2023] [Accepted: 03/26/2024] [Indexed: 04/28/2024]
Abstract
The supraspinal descending pain modulatory system (DPMS) shapes pain perception via monoaminergic modulation of sensory information in the spinal cord. However, the role and synaptic mechanisms of descending noradrenergic signaling remain unclear. Here, we establish that noradrenergic neurons of the locus coeruleus (LC) are essential for supraspinal opioid antinociception. While much previous work has emphasized the role of descending serotonergic pathways, we find that opioid antinociception is primarily driven by excitatory output from the ventrolateral periaqueductal gray (vlPAG) to the LC. Furthermore, we identify a previously unknown opioid-sensitive inhibitory input from the rostroventromedial medulla (RVM), the suppression of which disinhibits LC neurons to drive spinal noradrenergic antinociception. We describe pain-related activity throughout this circuit and report the presence of prominent bifurcating outputs from the vlPAG to the LC and the RVM. Our findings substantially revise current models of the DPMS and establish a supraspinal antinociceptive pathway that may contribute to multiple forms of descending pain modulation.
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Affiliation(s)
- Susan T. Lubejko
- Department of Neurobiology, School of Biological Sciences, University of California, San Diego, La Jolla, CA 92093, USA
- Neurosciences Graduate Program, University of California, San Diego, La Jolla, CA 92093, USA
| | - Giulia Livrizzi
- Department of Neurobiology, School of Biological Sciences, University of California, San Diego, La Jolla, CA 92093, USA
- Biological Sciences Graduate Program, University of California, San Diego, La Jolla, CA 92093, USA
| | - Stanley A. Buczynski
- Department of Neurobiology, School of Biological Sciences, University of California, San Diego, La Jolla, CA 92093, USA
- Chemistry and Biochemistry Graduate Program, University of California, San Diego, La Jolla, CA 92093, USA
| | - Janki Patel
- Department of Neurobiology, School of Biological Sciences, University of California, San Diego, La Jolla, CA 92093, USA
| | - Jean C. Yung
- Department of Neurobiology, School of Biological Sciences, University of California, San Diego, La Jolla, CA 92093, USA
| | - Tony L. Yaksh
- Departments of Anesthesiology and Pharmacology, University of California, San Diego, La Jolla, CA 92093, USA
| | - Matthew R. Banghart
- Department of Neurobiology, School of Biological Sciences, University of California, San Diego, La Jolla, CA 92093, USA
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Tseng CT, Welch HF, Gi AL, Kang EM, Mamidi T, Pydimarri S, Ramesh K, Sandoval A, Ploski JE, Thorn CA. Frequency Specific Optogenetic Stimulation of the Locus Coeruleus Induces Task-Relevant Plasticity in the Motor Cortex. J Neurosci 2024; 44:e1528232023. [PMID: 38124020 PMCID: PMC10869157 DOI: 10.1523/jneurosci.1528-23.2023] [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: 08/10/2023] [Revised: 12/07/2023] [Accepted: 12/10/2023] [Indexed: 12/23/2023] Open
Abstract
The locus ceruleus (LC) is the primary source of neocortical noradrenaline, which is known to be involved in diverse brain functions including sensory perception, attention, and learning. Previous studies have shown that LC stimulation paired with sensory experience can induce task-dependent plasticity in the sensory neocortex and in the hippocampus. However, it remains unknown whether LC activation similarly impacts neural representations in the agranular motor cortical regions that are responsible for movement planning and production. In this study, we test whether optogenetic stimulation of the LC paired with motor performance is sufficient to induce task-relevant plasticity in the somatotopic cortical motor map. Male and female TH-Cre + rats were trained on a skilled reaching lever-pressing task emphasizing the use of the proximal forelimb musculature, and a viral approach was used to selectively express ChR2 in noradrenergic LC neurons. Once animals reached criterial behavioral performance, they received five training sessions in which correct task performance was paired with optogenetic stimulation of the LC delivered at 3, 10, or 30 Hz. After the last stimulation session, motor cortical mapping was performed using intracortical microstimulation. Our results show that lever pressing paired with LC stimulation at 10 Hz, but not at 3 or 30 Hz, drove the expansion of the motor map representation of the task-relevant proximal FL musculature. These findings demonstrate that phasic, training-paired activation of the LC is sufficient to induce experience-dependent plasticity in the agranular motor cortex and that this LC-driven plasticity is highly dependent on the temporal dynamics of LC activation.
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Affiliation(s)
- Ching-Tzu Tseng
- Department of Neuroscience, The University of Texas at Dallas, Richardson 75080, Texas
| | - Hailey F Welch
- Department of Neuroscience, The University of Texas at Dallas, Richardson 75080, Texas
| | - Ashley L Gi
- Department of Neuroscience, The University of Texas at Dallas, Richardson 75080, Texas
| | - Erica Mina Kang
- Department of Neuroscience, The University of Texas at Dallas, Richardson 75080, Texas
| | - Tanushree Mamidi
- Department of Neuroscience, The University of Texas at Dallas, Richardson 75080, Texas
| | - Sahiti Pydimarri
- Department of Neuroscience, The University of Texas at Dallas, Richardson 75080, Texas
| | - Kritika Ramesh
- Department of Neuroscience, The University of Texas at Dallas, Richardson 75080, Texas
| | - Alfredo Sandoval
- Department of Neurobiology, The University of Texas Medical Branch, Galveston 77555, Texas
| | - Jonathan E Ploski
- Department of Neural and Behavioral Sciences, Penn State College of Medicine, Hershey 17033-0850, Pennsylvania
| | - Catherine A Thorn
- Department of Neuroscience, The University of Texas at Dallas, Richardson 75080, Texas,
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Patel M, Joshi B. Development of the sleep-wake switch in rats during the P2-P21 early infancy period. FRONTIERS IN NETWORK PHYSIOLOGY 2024; 3:1340722. [PMID: 38239232 PMCID: PMC10794532 DOI: 10.3389/fnetp.2023.1340722] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/18/2023] [Accepted: 12/14/2023] [Indexed: 01/22/2024]
Abstract
In early infancy, rats randomly alternate between the sleeping and waking states-from postnatal day 2-10 (P2-P10), sleep and wake bouts are both exponentially distributed with increasing means, while from P10-P21 sleep and wake bout means continue to increase, though there is a striking qualitative shift in the distribution of wake bouts from exponential to power law. The behavioral states of sleep and wakefulness correspond to the activity of sleep-active and wake-active neuronal brainstem populations, with reciprocal inhibition between the two ensuring that only one population is active at a time. The locus coeruleus (LC) forms a third component of this circuit that rises in prominence during the P10-P21 period, as experimental evidence shows that an as-of-yet undeciphered interaction of the LC with sleep-active and wake-active populations is responsible for the transformation of the wake bout distribution from exponential to power law. Interestingly, the LC undergoes remarkable physiological changes during the P10-P21 period-gap junctions within the LC are pruned and network-wide oscillatory synchrony declines and vanishes. In this work, we discuss a series of models of sleep-active, wake-active, and the LC populations, and we use these models to postulate the nature of the interaction between these three populations and how these interactions explain empirical observations of sleep and wake bout dynamics. We hypothesize a circuit in which there is reciprocal excitation between the LC and wake-active population with inhibition from the sleep-active population to the LC that suppresses the LC during sleep bouts. During the P2-P10 period, we argue that a noise-based switching mechanism between the sleep-active and wake-active populations provides a simple and natural way to account for exponential bout distributions, and that the locked oscillatory state of the LC prevents it from impacting bout distributions. From P10-P21, we use our models to postulate that, as the LC gradually shifts from a state of synchronized oscillations to a state of continuous firing, reciprocal excitation between the LC and the wake-active population is able to gradually transform the wake bout distribution from exponential to power law.
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Affiliation(s)
- Mainak Patel
- Department of Mathematics, William & Mary, Williamsburg, VA, United States
| | - Badal Joshi
- Department of Mathematics, California State University San Marcos, San Marcos, CA, United States
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Cahill MK, Perez YR, Larpthaveesarp A, Etchenique R, Poskanzer KE. A Photoactivatable Norepinephrine for Probing Adrenergic Neural Circuits. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.13.566764. [PMID: 38014204 PMCID: PMC10680792 DOI: 10.1101/2023.11.13.566764] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2023]
Abstract
Norepinephrine (NE) is a critical neuromodulator that mediates a wide range of behavior and neurophysiology, including attention, arousal, plasticity, and memory consolidation. A major source of NE is the brainstem nucleus the locus coeruleus (LC), which sends widespread projections throughout the central nervous system (CNS). Efforts to dissect this complex noradrenergic circuitry have driven the development of many tools that detect endogenous NE or modulate widespread NE release via LC activation and inhibition. While these tools have enabled research that elucidates physiological roles of NE, additional tools to probe these circuits with a higher degree of spatial precision could enable a finer delineation of function. Here, we describe the synthesis and chemical properties of a photo-activatable NE, [Ru(bpy) 2 (PMe 3 )(NE)]PF 6 (RuBi-NE). We validate the one-photon (1P) release of NE using whole-cell patch clamp electrophysiology in acute mouse brain slices containing the LC. We show that a 10 ms pulse of blue light, in the presence of RuBi-NE, briefly modulates the firing rate of LC neurons via α-2 adrenergic receptors. The development of a photo-activatable NE that can be released with light in the visible spectrum provides a new tool for fine-grained mapping of complex noradrenergic circuits, as well as the ability to probe how NE acts on non-neuronal cells in the CNS.
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McKinney A, Hu M, Hoskins A, Mohammadyar A, Naeem N, Jing J, Patel SS, Sheth BR, Jiang X. Cellular composition and circuit organization of the locus coeruleus of adult mice. eLife 2023; 12:e80100. [PMID: 36734517 PMCID: PMC9934863 DOI: 10.7554/elife.80100] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2022] [Accepted: 02/01/2023] [Indexed: 02/04/2023] Open
Abstract
The locus coeruleus (LC) houses the vast majority of noradrenergic neurons in the brain and regulates many fundamental functions, including fight and flight response, attention control, and sleep/wake cycles. While efferent projections of the LC have been extensively investigated, little is known about its local circuit organization. Here, we performed large-scale multipatch recordings of noradrenergic neurons in adult mouse LC to profile their morpho-electric properties while simultaneously examining their interactions. LC noradrenergic neurons are diverse and could be classified into two major morpho-electric types. While fast excitatory synaptic transmission among LC noradrenergic neurons was not observed in our preparation, these mature LC neurons connected via gap junction at a rate similar to their early developmental stage and comparable to other brain regions. Most electrical connections form between dendrites and are restricted to narrowly spaced pairs or small clusters of neurons of the same type. In addition, more than two electrically coupled cell pairs were often identified across a cohort of neurons from individual multicell recording sets that followed a chain-like organizational pattern. The assembly of LC noradrenergic neurons thus follows a spatial and cell-type-specific wiring principle that may be imposed by a unique chain-like rule.
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Affiliation(s)
- Andrew McKinney
- Neuroscience Graduate Program, Baylor College of MedicineHoustonUnited States
- Department of Neuroscience, Baylor College of MedicineHoustonUnited States
- Jan and Dan Duncan Neurological Research Institute at Texas Children’s HospitalHoustonUnited States
| | - Ming Hu
- Department of Neuroscience, Baylor College of MedicineHoustonUnited States
- Jan and Dan Duncan Neurological Research Institute at Texas Children’s HospitalHoustonUnited States
| | | | | | | | - Junzhan Jing
- Department of Neuroscience, Baylor College of MedicineHoustonUnited States
- Jan and Dan Duncan Neurological Research Institute at Texas Children’s HospitalHoustonUnited States
| | - Saumil S Patel
- Department of Neuroscience, Baylor College of MedicineHoustonUnited States
| | - Bhavin R Sheth
- Department of Electrical and Computer Engineering, University of HoustonHoustonUnited States
- Center for NeuroEngineering and Cognitive Science, University of HoustonHoustonUnited States
| | - Xiaolong Jiang
- Neuroscience Graduate Program, Baylor College of MedicineHoustonUnited States
- Department of Neuroscience, Baylor College of MedicineHoustonUnited States
- Jan and Dan Duncan Neurological Research Institute at Texas Children’s HospitalHoustonUnited States
- Department of Ophthalmology, Baylor College of MedicineHoustonUnited States
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Barcomb K, Olah SS, Kennedy MJ, Ford CP. Properties and modulation of excitatory inputs to the locus coeruleus. J Physiol 2022; 600:4897-4916. [PMID: 36156249 PMCID: PMC9669264 DOI: 10.1113/jp283605] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2022] [Accepted: 09/22/2022] [Indexed: 01/12/2023] Open
Abstract
Excitatory inputs drive burst firing of locus coeruleus (LC) noradrenaline (NA) neurons in response to a variety of stimuli. Though a small number of glutamatergic LC afferents have been investigated, the overall landscape of these excitatory inputs is largely unknown. The current study used an optogenetic approach to isolate three glutamatergic afferents: the prefrontal cortex (PFC), lateral hypothalamus (LH) and periaqueductal grey (PAG). AAV5-DIO-ChR2 was injected into each region in male and female CaMKII-Cre mice and the properties of excitatory inputs on LC-NA cells were measured. Notably we found differences among these inputs. First, the pattern of axonal innervation differed between inputs such that LH afferents were concentrated in the posterior portion of the LC-NA somatic region while PFC afferents were denser in the medial dendritic region. Second, basal intrinsic properties varied for afferents, with LH inputs having the highest connectivity and the largest amplitude excitatory postsynaptic currents while PAG inputs had the lowest initial release probability. Third, while orexin and oxytocin had minimal effects on any input, dynorphin strongly inhibited excitatory inputs originating from the LH and PAG, and corticotrophin releasing factor (CRF) selectively inhibited inputs from the PAG. Overall, these results demonstrate that individual afferents to the LC have differing properties, which may contribute to the modularity of the LC and its ability to mediate various behavioural outcomes. KEY POINTS: Excitatory inputs to the locus coeruleus (LC) are important for driving noradrenaline neuron activity and downstream behaviours in response to salient stimuli, but little is known about the functional properties of different glutamate inputs that innervate these neurons We used a virus-mediated optogenetic approach to compare glutamate afferents from the prefrontal cortex (PFC), the lateral hypothalamus (LH) and the periaqueductal grey (PAG). While PFC was predicted to make synaptic inputs, we found that the LH and PAG also drove robust excitatory events in LC noradrenaline neurons. The strength, kinetics, and short-term plasticity of each input differed as did the extent of neuromodulation by both dynorphin and corticotrophin releasing factor. Thus each input displayed a unique set of basal properties and modulation by peptides. This characterization is an important step in deciphering the heterogeneity of the LC.
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Affiliation(s)
- Kelsey Barcomb
- Department of PharmacologyUniversity of Colorado School of MedicineAuroraCOUSA
| | - Samantha S. Olah
- Department of PharmacologyUniversity of Colorado School of MedicineAuroraCOUSA
| | - Matthew J. Kennedy
- Department of PharmacologyUniversity of Colorado School of MedicineAuroraCOUSA
| | - Christopher P. Ford
- Department of PharmacologyUniversity of Colorado School of MedicineAuroraCOUSA
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Kumar GA, Puthenveedu MA. Diversity and specificity in location-based signaling outputs of neuronal GPCRs. Curr Opin Neurobiol 2022; 76:102601. [DOI: 10.1016/j.conb.2022.102601] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Revised: 05/27/2022] [Accepted: 06/01/2022] [Indexed: 11/30/2022]
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Zhu F, Liu L, Li J, Liu B, Wang Q, Jiao R, Xu Y, Wang L, Sun S, Sun X, Younus M, Wang C, Hokfelt T, Zhang B, Gu H, Xu ZQD, Zhou Z. Cocaine increases quantal norepinephrine secretion through NET-dependent PKC activation in locus coeruleus neurons. Cell Rep 2022; 40:111199. [PMID: 35977516 DOI: 10.1016/j.celrep.2022.111199] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2021] [Revised: 04/20/2022] [Accepted: 07/20/2022] [Indexed: 11/25/2022] Open
Abstract
The norepinephrine neurons in locus coeruleus (LC-NE neurons) are essential for sleep arousal, pain sensation, and cocaine addiction. According to previous studies, cocaine increases NE overflow (the profile of extracellular NE level in response to stimulation) by blocking the NE reuptake. NE overflow is determined by NE release via exocytosis and reuptake through NE transporter (NET). However, whether cocaine directly affects vesicular NE release has not been directly tested. By recording quantal NE release from LC-NE neurons, we report that cocaine directly increases the frequency of quantal NE release through regulation of NET and downstream protein kinase C (PKC) signaling, and this facilitation of NE release modulates the activity of LC-NE neurons and cocaine-induced stimulant behavior. Thus, these findings expand the repertoire of mechanisms underlying the effects of cocaine on NE (pro-release and anti-reuptake), demonstrate NET as a release enhancer in LC-NE neurons, and provide potential sites for treatment of cocaine addiction.
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Affiliation(s)
- Feipeng Zhu
- State Key Laboratory of Membrane Biology and Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular Medicine, College of Future Technology and Peking-Tsinghua Center for Life Sciences and PKU-IDG/McGovern Institute for Brain Research, Peking University, Beijing 100871, China
| | - Lina Liu
- State Key Laboratory of Membrane Biology and Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular Medicine, College of Future Technology and Peking-Tsinghua Center for Life Sciences and PKU-IDG/McGovern Institute for Brain Research, Peking University, Beijing 100871, China; Core Facilities Center, Departments of Neurobiology and Pathology, Beijing Key Laboratory of Neural Regeneration and Repair, Beijing Institute for Brain Disorders, Capital Medical University, Beijing 100069, China
| | - Jie Li
- State Key Laboratory of Membrane Biology and Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular Medicine, College of Future Technology and Peking-Tsinghua Center for Life Sciences and PKU-IDG/McGovern Institute for Brain Research, Peking University, Beijing 100871, China
| | - Bing Liu
- State Key Laboratory of Membrane Biology and Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular Medicine, College of Future Technology and Peking-Tsinghua Center for Life Sciences and PKU-IDG/McGovern Institute for Brain Research, Peking University, Beijing 100871, China
| | - Qinglong Wang
- State Key Laboratory of Membrane Biology and Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular Medicine, College of Future Technology and Peking-Tsinghua Center for Life Sciences and PKU-IDG/McGovern Institute for Brain Research, Peking University, Beijing 100871, China
| | - Ruiying Jiao
- State Key Laboratory of Membrane Biology and Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular Medicine, College of Future Technology and Peking-Tsinghua Center for Life Sciences and PKU-IDG/McGovern Institute for Brain Research, Peking University, Beijing 100871, China
| | - Yongxin Xu
- State Key Laboratory of Membrane Biology and Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular Medicine, College of Future Technology and Peking-Tsinghua Center for Life Sciences and PKU-IDG/McGovern Institute for Brain Research, Peking University, Beijing 100871, China
| | - Lun Wang
- State Key Laboratory of Membrane Biology and Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular Medicine, College of Future Technology and Peking-Tsinghua Center for Life Sciences and PKU-IDG/McGovern Institute for Brain Research, Peking University, Beijing 100871, China
| | - Suhua Sun
- State Key Laboratory of Membrane Biology and Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular Medicine, College of Future Technology and Peking-Tsinghua Center for Life Sciences and PKU-IDG/McGovern Institute for Brain Research, Peking University, Beijing 100871, China
| | - Xiaoxuan Sun
- State Key Laboratory of Membrane Biology and Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular Medicine, College of Future Technology and Peking-Tsinghua Center for Life Sciences and PKU-IDG/McGovern Institute for Brain Research, Peking University, Beijing 100871, China
| | - Muhammad Younus
- State Key Laboratory of Membrane Biology and Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular Medicine, College of Future Technology and Peking-Tsinghua Center for Life Sciences and PKU-IDG/McGovern Institute for Brain Research, Peking University, Beijing 100871, China
| | - Changhe Wang
- State Key Laboratory of Membrane Biology and Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular Medicine, College of Future Technology and Peking-Tsinghua Center for Life Sciences and PKU-IDG/McGovern Institute for Brain Research, Peking University, Beijing 100871, China
| | - Tomas Hokfelt
- Department of Neuroscience, Karolinska Institute, 171 71 Stockholm, Sweden
| | - Bo Zhang
- School of Chemical Biology and Biotechnology, Peking University Shenzhen Graduate School, Shenzhen 518055, China; Institute of Neurological and Psychiatric Disorders, Shenzhen Bay Laboratory, Shenzhen 518132, China.
| | - Howard Gu
- Department of Biological Chemistry and Pharmacology, Ohio State University College of Medicine, Columbus, OH 43210, USA.
| | - Zhi-Qing David Xu
- Core Facilities Center, Departments of Neurobiology and Pathology, Beijing Key Laboratory of Neural Regeneration and Repair, Beijing Institute for Brain Disorders, Capital Medical University, Beijing 100069, China.
| | - Zhuan Zhou
- State Key Laboratory of Membrane Biology and Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular Medicine, College of Future Technology and Peking-Tsinghua Center for Life Sciences and PKU-IDG/McGovern Institute for Brain Research, Peking University, Beijing 100871, China.
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Papesh MH, Guevara Pinto JD. Spotting rare items makes the brain "blink" harder: Evidence from pupillometry. Atten Percept Psychophys 2019; 81:2635-2647. [PMID: 31222658 PMCID: PMC6858538 DOI: 10.3758/s13414-019-01777-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
In many visual search tasks (e.g., cancer screening, airport baggage inspections), the most serious search targets occur infrequently. As an ironic side effect, when observers finally encounter important objects (e.g., a weapon in baggage), they often fail to notice them, a phenomenon known as the low-prevalence effect (LPE). Although many studies have investigated LPE search errors, we investigated the attentional consequences of successful rare target detection. Using an attentional blink paradigm, we manipulated how often observers encountered the first serial target (T1), then measured its effects on their ability to detect a following target (T2). Across two experiments, we show that the LPE is more than just an inflated miss rate: When observers successfully detected rare targets, they were less likely to spot subsequent targets. Using pupillometry to index locus-coeruleus (LC) mediated attentional engagement, Experiment 2 confirmed that an LC refractory period mediates the attentional blink (`Nieuwenhuis, Gilzenrat, Holmes, & Cohen, 2005, Journal of Experimental Psychology: General, 134[3], 291-307), and that these effects emerge relatively quickly following T1 onset. Moreover, in both behavioral and pupil analyses, we found that detecting low-prevalence targets exacerbates the LC refractory period. Consequences for theories of the LPE are discussed.
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Affiliation(s)
- Megan H Papesh
- Department of Psychology, Louisiana State University, Baton Rouge, LA, USA.
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10
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Torralva R, Janowsky A. Noradrenergic Mechanisms in Fentanyl-Mediated Rapid Death Explain Failure of Naloxone in the Opioid Crisis. J Pharmacol Exp Ther 2019; 371:453-475. [PMID: 31492824 DOI: 10.1124/jpet.119.258566] [Citation(s) in RCA: 89] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2019] [Accepted: 09/03/2019] [Indexed: 12/25/2022] Open
Abstract
In December 2018, the Centers for Disease Control declared fentanyl the deadliest drug in America. Opioid overdose is the single greatest cause of death in the United States adult population (ages 18-50), and fentanyl and its analogs [fentanyl/fentanyl analogs (F/FAs)] are currently involved in >50% of these deaths. Anesthesiologists in the United States were introduced to fentanyl in the early 1970s when it revolutionized surgical anesthesia by combining profound analgesia with hemodynamic stability. However, they quickly had to master its unique side effect. F/FAs can produce profound rigidity in the diaphragm, chest wall and upper airway within an extremely narrow dosing range. This clinical effect was called wooden chest syndrome (WCS) by anesthesiologists and is not commonly known outside of anesthesiology or to clinicians or researchers in addiction research/medicine. WCS is almost routinely fatal without expert airway management. This review provides relevant clinical human pharmacology and animal data demonstrating that the significant increase in the number of F/FA-induced deaths may involve α-adrenergic and cholinergic receptor-mediated mechanical failure of the respiratory and cardiovascular systems with rapid development of rigidity and airway closure. Although morphine and its prodrug, heroin, can cause mild rigidity in abdominal muscles at high doses, neither presents with the distinct and rapid respiratory failure seen with F/FA-induced WCS, separating F/FA overdose from the slower onset of respiratory depression caused by morphine-derived alkaloids. This distinction has significant consequences for the design and implementation of new pharmacologic strategies to effectively prevent F/FA-induced death. SIGNIFICANCE STATEMENT: Deaths from fentanyl and F/FAs are increasing in spite of availability and awareness of the opioid reversal drug naloxone. This article reviews literature suggesting that naloxone may be ineffective against centrally mediated noradrenergic and cholinergic effects of F/FAs, which clinically manifest as severe muscle rigidity and airway compromise (e.g., wooden chest syndrome) that is rapid and distinct from respiratory depression seen with morphine-derived alkaloids. A physiologic model is proposed and implications for new drug development and treatment are discussed.
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Affiliation(s)
- Randy Torralva
- CODA Inc., Research Department, Portland, Oregon (R.T.); Research Service, VA Portland Health Care System, Portland, Oregon (R.T., A.J.); and Department of Psychiatry, Oregon Health & Science University, Portland, Oregon (R.T., A.J.)
| | - Aaron Janowsky
- CODA Inc., Research Department, Portland, Oregon (R.T.); Research Service, VA Portland Health Care System, Portland, Oregon (R.T., A.J.); and Department of Psychiatry, Oregon Health & Science University, Portland, Oregon (R.T., A.J.)
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11
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Uematsu A, Tan BZ, Johansen JP. Projection specificity in heterogeneous locus coeruleus cell populations: implications for learning and memory. Learn Mem 2015; 22:444-51. [PMID: 26330494 PMCID: PMC4561410 DOI: 10.1101/lm.037283.114] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2015] [Accepted: 06/22/2015] [Indexed: 01/05/2023]
Abstract
Noradrenergic neurons in the locus coeruleus (LC) play a critical role in many functions including learning and memory. This relatively small population of cells sends widespread projections throughout the brain including to a number of regions such as the amygdala which is involved in emotional associative learning and the medial prefrontal cortex which is important for facilitating flexibility when learning rules change. LC noradrenergic cells participate in both of these functions, but it is not clear how this small population of neurons modulates these partially distinct processes. Here we review anatomical, behavioral, and electrophysiological studies to assess how LC noradrenergic neurons regulate these different aspects of learning and memory. Previous work has demonstrated that subpopulations of LC noradrenergic cells innervate specific brain regions suggesting heterogeneity of function in LC neurons. Furthermore, noradrenaline in mPFC and amygdala has distinct effects on emotional learning and cognitive flexibility. Finally, neural recording data show that LC neurons respond during associative learning and when previously learned task contingencies change. Together, these studies suggest a working model in which distinct and potentially opposing subsets of LC neurons modulate particular learning functions through restricted efferent connectivity with amygdala or mPFC. This type of model may provide a general framework for understanding other neuromodulatory systems, which also exhibit cell type heterogeneity and projection specificity.
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Affiliation(s)
- Akira Uematsu
- RIKEN Brain Science Institute, Laboratory for Neural Circuitry of Memory, 2-1 Hirosawa, Wako-shi, Saitama 351-0198, Japan
| | - Bao Zhen Tan
- RIKEN Brain Science Institute, Laboratory for Neural Circuitry of Memory, 2-1 Hirosawa, Wako-shi, Saitama 351-0198, Japan
| | - Joshua P Johansen
- RIKEN Brain Science Institute, Laboratory for Neural Circuitry of Memory, 2-1 Hirosawa, Wako-shi, Saitama 351-0198, Japan Department of Life Sciences, Graduate School of Arts and Sciences, University of Tokyo, Tokyo 153-8902, Japan
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Patel M, Joshi B. Modeling the evolving oscillatory dynamics of the rat locus coeruleus through early infancy. Brain Res 2015; 1618:181-93. [DOI: 10.1016/j.brainres.2015.05.033] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2015] [Revised: 05/05/2015] [Accepted: 05/23/2015] [Indexed: 11/25/2022]
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Hajhashemi V, Minaiyan M, Banafshe HR, Mesdaghinia A, Abed A. The anti-inflammatory effects of venlafaxine in the rat model of carrageenan-induced paw edema. IRANIAN JOURNAL OF BASIC MEDICAL SCIENCES 2015; 18:654-8. [PMID: 26351555 PMCID: PMC4556757] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/18/2014] [Accepted: 06/01/2015] [Indexed: 10/24/2022]
Abstract
OBJECTIVES Recently anti-inflammatory effects of antidepressants have been demonstrated. Venlafaxine belongs to newer antidepressants with serotonin norepinephrine reuptake inhibition property. The pain alleviating properties of venlafaxine in different pain models such as neurogenic pain, diabetic neuropathy, and fibromyalgia have been demonstrated. Anti-inflammatory effects of venlafaxine and also its underlying mechanisms remain unclear. The present study was designed to evaluate the anti-inflammatory effects of venlafaxine and determine possible underlying mechanisms. MATERIALS AND METHODS We examined the anti-inflammatory effects of intraperitoneal (IP) and intracerebroventricular (ICV) administration of venlafaxine in the rat model of carrageenan-induced paw edema. RESULTS Our results showed that both IP (50 and 100 mg/kg) and ICV (50 and 100 μg/rat) injection of venlafaxine inhibited carrageenan-induced paw edema. Also IP and ICV administration of venlafaxine significantly decreased myeloperoxidase (MPO) activity and interleukin (IL)-1β and tumor necrosis factor (TNF)-α production. Finally, we tried to reverse the anti-inflammatory effect of venlafaxine by yohimbine (5 mg/kg, IP), an alpha2-adrenergic antagonist. Our results showed that applied antagonist failed to change the anti-inflammatory effect of venlafaxine. CONCLUSION These results demonstrated that venlafaxine has potent anti-inflammatory effect which is related to the peripheral and central effects of this drug. Also we have shown that anti-inflammatory effect of venlafaxine is mediated mostly through the inhibition of IL-1β and TNF-α production and decreases MPO activity in the site of inflammation.
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Affiliation(s)
- Valiollah Hajhashemi
- Department of Pharmacology and Toxicology and Isfahan Pharmaceutical Research Center, School of Pharmacy and Pharmaceutical Sciences, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Mohsen Minaiyan
- Department of Pharmacology and Toxicology and Isfahan Pharmaceutical Research Center, School of Pharmacy and Pharmaceutical Sciences, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Hamid Reza Banafshe
- Physiology Research Center, Kashan University of Medical Sciences, Kashan, Iran,Department of Pharmacology, School of Medicine, Kashan University of Medical Sciences, Kashan, Iran
| | - Azam Mesdaghinia
- Physiology Research Center, Kashan University of Medical Sciences, Kashan, Iran,Department of Pharmacology, School of Medicine, Kashan University of Medical Sciences, Kashan, Iran
| | - Alireza Abed
- Department of Pharmacology, School of Medicine, Kashan University of Medical Sciences, Kashan, Iran,Corresponding author: Alireza Abed. Department of Pharmacology, School of Medicine, Kashan University of Medical Sciences, Kashan, Iran. Tel: +98-313-7922695; Fax: +98-311-6680011;
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The timing of dopamine- and noradrenaline-mediated transmission reflects underlying differences in the extent of spillover and pooling. J Neurosci 2014; 34:7645-56. [PMID: 24872568 DOI: 10.1523/jneurosci.0166-14.2014] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Metabotropic transmission typically occurs through the spillover activation of extrasynaptic receptors. This study examined the mechanisms underlying somatodendritic dopamine and noradrenaline transmission and found that the extent of spillover and pooling varied dramatically between these two transmitters. In the mouse ventral tegmental area, the time course of D2-receptor-mediated IPSCs (D2-IPSCs) was consistent between cells and was unaffected by altering stimulation intensity, probability of release, or the extent of diffusion. Blocking dopamine reuptake with cocaine extended the time course of D2-IPSCs and suggested that transporters strongly limited spillover. As a result, individual release sites contributed independently to the duration of D2-IPSCs. In contrast, increasing the release of noradrenaline in the rat locus ceruleus prolonged the duration of α2-receptor-mediated IPSCs even when reuptake was intact. Spillover and subsequent pooling of noradrenaline activated distal α2-receptors, which prolonged the duration of α2-IPSCs when multiple release sites were activated synchronously. By using the rapid application of agonists onto large macropatches, we determined the concentration profile of agonists underlying the two IPSCs. Incorporating the results into a model simulating extracellular diffusion predicted that the functional range of noradrenaline diffusion was nearly fivefold greater in the locus ceruleus than dopamine in the midbrain. This study demonstrates that catecholamine synapses differentially regulate the extent of spillover and pooling to control the timing of local inhibition and suggests diversity in the roles of uptake and diffusion in governing metabotropic transmission.
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Henderson G. The μ-opioid receptor: an electrophysiologist's perspective from the sharp end. Br J Pharmacol 2014; 172:260-7. [PMID: 24640948 DOI: 10.1111/bph.12633] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2013] [Revised: 12/02/2013] [Accepted: 12/10/2013] [Indexed: 12/18/2022] Open
Abstract
UNLABELLED Morphine, the prototypical opioid analgesic drug, produces its behavioural effects primarily through activation of μ-opioid receptors expressed in neurones of the central and peripheral nervous systems. This perspective provides a historical view of how, over the past 40 years, the use of electrophysiological recording techniques has helped to reveal the molecular mechanisms by which acute and chronic activation of μ-opioid receptors by morphine and other opioid drugs modify neuronal function. LINKED ARTICLES This article is part of a themed section on Opioids: New Pathways to Functional Selectivity. To view the other articles in this section visit http://dx.doi.org/10.1111/bph.2015.172.issue-2.
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Affiliation(s)
- Graeme Henderson
- School of Physiology and Pharmacology, University of Bristol, Bristol, UK
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Hajhashemi V, Banafshe HR, Minaiyan M, Mesdaghinia A, Abed A. Antinociceptive effects of venlafaxine in a rat model of peripheral neuropathy: role of alpha2-adrenergic receptors. Eur J Pharmacol 2014; 738:230-6. [PMID: 24861021 DOI: 10.1016/j.ejphar.2014.04.046] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2014] [Revised: 03/17/2014] [Accepted: 04/20/2014] [Indexed: 11/27/2022]
Abstract
This study was designed to determine whether acute or chronic venlafaxine administration was effective in alleviating symptoms of neuropathic pain in a rat model of neuropathic pain, and whether the effect of venlafaxine involved manipulation of α2-adrenoceptors,by determining the effect of yohimbine, a α2-adrenoceptor antagonist on its actions. Neuropathic pain was induced by chronic constriction injury (CCI) of the sciatic nerve in the rats that resulted in stimulus-evoked thermal hyperalgesia, tactile mechanical and cold allodynia. Acute venlafaxine injections (20 and 40 mg/kg i.p.) on the 7th, 14th and 21st postoperative days could not reduce tactile and cold hypersensitivity significantly compared to CCI group. But in these groups venlafaxine (40 mg/kg i.p.) blocked heat hyperalgesia. When venlafaxine (10 and 20mg/kg i.p.) administration was started on the first day after CCI and given daily until the 14th day, tactile hypersensitivity and heat hyperalgesia considerably were attenuated. But when venlafaxine (20mg/kg i.p.) treatment was initiated on the 10th day after CCI, once the model had been fully established, and given daily for 11 days, no differences in withdrawal thresholds were observed compared with CCI group however heat hyperalgesia significantly has been blocked. Also the effect of venlafaxine on heat hyperalgesia was reversed by pretreatment with yohimbine at all-time intervals. These results indicate that venlafaxine, when administered immediately after nerve injury, and for a sufficient period of time, can prevent the development and expression of neuropathic pain. Also we conclude that α2-adrenoceptors participate in the antinociceptive effects of venlafaxine.
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Affiliation(s)
- Valiollah Hajhashemi
- Department of Pharmacology and Toxicology and Isfahan Pharmaceutical Research Center, School of Pharmacy and Pharmaceutical Sciences, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Hamid Reza Banafshe
- Physiology Research Center, Kashan University of Medical Sciences, Kashan, Iran; Department of Addiction Studies, School of Medicine, Kashan University of Medical Sciences, Kashan, Iran
| | - Mohsen Minaiyan
- Department of Pharmacology and Toxicology and Isfahan Pharmaceutical Research Center, School of Pharmacy and Pharmaceutical Sciences, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Azam Mesdaghinia
- Physiology Research Center, Kashan University of Medical Sciences, Kashan, Iran
| | - Alireza Abed
- Department of Pharmacology and Toxicology, School of Pharmacy and Pharmaceutical Sciences, Isfahan University of Medical Sciences, Isfahan, Iran.
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Monosynaptic glutamatergic activation of locus coeruleus and other lower brainstem noradrenergic neurons by the C1 cells in mice. J Neurosci 2014; 33:18792-805. [PMID: 24285886 DOI: 10.1523/jneurosci.2916-13.2013] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The C1 neurons, located in the rostral ventrolateral medulla (VLM), are activated by pain, hypotension, hypoglycemia, hypoxia, and infection, as well as by psychological stress. Prior work has highlighted the ability of these neurons to increase sympathetic tone, hence peripheral catecholamine release, probably via their direct excitatory projections to sympathetic preganglionic neurons. In this study, we use channelrhodopsin-2 (ChR2) optogenetics to test whether the C1 cells are also capable of broadly activating the brain's noradrenergic system. We selectively expressed ChR2(H134R) in rostral VLM catecholaminergic neurons by injecting Cre-dependent adeno-associated viral vectors into the brain of adult dopamine-β-hydroxylase (DβH)(Cre/0) mice. Most ChR2-expressing VLM neurons (75%) were immunoreactive for phenylethanolamine N-methyl transferease, thus were C1 cells, and most of the ChR2-positive axonal varicosities were immunoreactive for vesicular glutamate transporter-2 (78%). We produced light microscopic evidence that the axons of rostral VLM (RVLM) catecholaminergic neurons contact locus coeruleus, A1, and A2 noradrenergic neurons, and ultrastructural evidence that these contacts represent asymmetric synapses. Using optogenetics in tissue slices, we show that RVLM catecholaminergic neurons activate the locus coeruleus as well as A1 and A2 noradrenergic neurons monosynaptically by releasing glutamate. In conclusion, activation of RVLM catecholaminergic neurons, predominantly C1 cells, by somatic or psychological stresses has the potential to increase the firing of both peripheral and central noradrenergic neurons.
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Biancardi V, Bícego KC, Gargaglioni LH. ATP in the locus coeruleus as a modulator of cardiorespiratory control in unanaesthetized male rats. Exp Physiol 2013; 99:232-47. [PMID: 24058188 DOI: 10.1113/expphysiol.2013.074195] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Locus coeruleus (LC) noradrenergic neurons are chemosensitive to CO2 and pH in mammals and amphibians and are involved in the CO2-related drive to breathe. Purinergic neuromodulation in the LC is of particular interest because ATP acts as a neuromodulator in brainstem regions involved in cardiovascular and respiratory regulation, such as the LC. ATP acting on LC P2 receptors influences the release of noradrenaline. Thus, the goal of the present study was to investigate the role of LC purinergic neuromodulation of ventilatory and cardiovascular responses in normocapnic and hypercapnic conditions in unanaesthetized male Wistar rats. We assessed the purinergic modulation of cardiorespiratory systems by microinjecting an ATP P2X receptor agonist [α,β-methylene ATP (α,β-meATP), 0.5 or 1 nmol in 40 nl] and two non-selective P2 receptor antagonists [pyridoxalphosphate-6-azophenyl-2',4'-disulfonic acid (PPADS), 0.5 or 1 nmol in 40 nl; and suramin, 1 nmol in 40 nl] into the LC. Pulmonary ventilation (measured by plethysmography), mean arterial pressure (MAP) and heart rate (HR) were determined before and after unilateral microinjection (40 nl) of α,β-meATP, PPADS, suramin or 0.9% saline (vehicle) into the LC. These measurements were made during a 60 min exposure to normocapnic conditions or a 30 min exposure to 7% CO2. Subsequently, animals undergoing pharmacological treatment were subjected to a 30 min exposure to normocapnic conditions as a recovery period. In normocapnic conditions, α,β-meATP did not affect any parameter, whereas PPADS decreased respiratory frequency and increased MAP and HR. Suramin increased MAP and HR but did not change ventilation. Moreover, hypercapnic conditions induced an increase in ventilation and a decrease in HR in all groups. In hypercapnic conditions, α,β-meATP increased ventilation but did not change cardiovascular parameters, whereas PPADS increased MAP but did not alter ventilation, and suramin increased both ventilation and MAP. Thus, our data suggest that purinergic signalling, specifically through P2 receptors, in the LC plays an important role in cardiorespiratory control in normocapnic and hypercapnic conditions in unanaesthetized rats.
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Affiliation(s)
- Vivian Biancardi
- L. H. Gargaglioni: Department of Animal Morphology and Physiology, Faculty of Agricultural Sciences and Veterinaria, São Paulo State University at Jaboticabal, Rod. Prof. Paulo Donato Castellane s/n, 14884-900 Jaboticabal, SP, Brazil.
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Dang VC, Chieng BC, Christie MJ. Prolonged Stimulation of μ-Opioid Receptors Produces β-Arrestin-2-Mediated Heterologous Desensitization of α2-Adrenoceptor Function in Locus Ceruleus Neurons. Mol Pharmacol 2012; 82:473-80. [DOI: 10.1124/mol.112.079350] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
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Kidani Y, Ishimatsu M, Akasu T. Methylphenidate enhances inhibitory synaptic transmission by increasing the content of norepinephrine in the locus coeruleus of juvenile rats. Kurume Med J 2011; 57:29-38. [PMID: 21727763 DOI: 10.2739/kurumemedj.57.29] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The present study examined the effect of methylphenidate (MPH), a psychostimulant, on nor-adrenergic transmission in the locus coeruleus (LC) of juvenile rats. Intracellular recordings showed that MPH (>3 µM) produced a hyperpolarizing response associated with a decrease in the rate of spontaneously firing action potentials. MPH (1 µM) enhanced the amplitude of the inhibitory postsynaptic potential (IPSP) mediated by norepinephrine (NE), but did not change the excitatory postsynaptic potential (EPSP) mediated by excitatory amino acids. Whole-cell patch-clamp recordings showed that MPH (0.3-30 µM) produced an outward current (I(MPH)) and enhanced the inhibitory postsynaptic current (IPSC) in neurons of the juvenile rat LC. MPH (30 µM) enhanced the NE-induced outward current (I(NE)). Bath-application of yohimbine (1 µM) produced an inward current and blocked the MPH-induced enhancement of the IPSC. Yohimbine (1 µM) depressed not only the I(NE) but also the I(MPH) in juvenile rat LC neurons. The current-voltage relationship of the I(MPH) showed inward rectification and reversed polarity at -91.1±4.3 mV (n=5). Ba(2+) (100 µM) blocked the I(MPH), indicating that the I(MPH) is mediated by Ba(2+)-sensitive inward rectifier K(+) current. These results suggest that MPH enhances inhibitory synaptic transmission by increasing the concentration of NE at noradrenergic synapses in juvenile rat LC neurons.
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Affiliation(s)
- Yuri Kidani
- Department of Physiology, Kurume University School of Medicine, Kurume, Japan
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21
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Hickman DL, Johnson SW. Evaluation of the aesthetics of physical methods of euthanasia of anesthetized rats. JOURNAL OF THE AMERICAN ASSOCIATION FOR LABORATORY ANIMAL SCIENCE : JAALAS 2011; 50:695-701. [PMID: 22330717 PMCID: PMC3189674] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Received: 02/03/2011] [Revised: 03/02/2011] [Accepted: 04/04/2011] [Indexed: 05/31/2023]
Abstract
Dissection of living brain tissue for in vitro experiments requires the use of a rapid euthanasia method. However, the method must not subject animals to unnecessary pain and must be aesthetically acceptable to experimenters. The purposes of the current study were to assess the aesthetics of 6 euthanasia methods, measure the procedure duration, and evaluate brain for pathology after each procedure. We digitally recorded euthanasia of isoflurane-anesthetized rats by 6 physical methods: anesthetic overdose, cardiac exsanguination, decapitation, closed intrathoracic transection of the great vessels and heart, thoracic percussion, and thoracotomy with rupture of great vessels. Volunteer researchers and animal caretakers watched the video and completed an associated questionnaire. Anesthetic overdose and cardiac exsanguinations were rated most aesthetically pleasing, although these procedures took the longest to complete. In contrast, decapitation and thoracic percussion were the least aesthetically pleasing, but these methods were the quickest. No demographic factor was identified that could predict whether a given euthanasia procedure would be favored for aesthetic reasons, and participants provided a wide variety of rationales for the aesthetic ratings they assigned. Although all of these euthanasia methods meet the criteria of approved methods of euthanasia of anesthetized rats as defined by the AVMA, aesthetic features and the scientific need for rapid euthanasia are both considerations in selecting a method.
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Affiliation(s)
- Debra L Hickman
- Research and Development, Veterans Affairs Medical Center, Oregon Health & Science University, Portland, OR, USA.
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23
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Silkis IG. Analysis of the effects of neuromodulators on the generation of spontaneous pontine-geniculate-occipital (PGO) waves. NEUROCHEM J+ 2010. [DOI: 10.1134/s1819712410030025] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Gompf HS, Greenberg JH, Aston-Jones G, Ianculescu AG, Scanlan TS, Dratman MB. 3-Monoiodothyronamine: the rationale for its action as an endogenous adrenergic-blocking neuromodulator. Brain Res 2010; 1351:130-140. [PMID: 20615397 PMCID: PMC2926234 DOI: 10.1016/j.brainres.2010.06.067] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2010] [Revised: 06/28/2010] [Accepted: 06/29/2010] [Indexed: 01/02/2023]
Abstract
The investigations reported here were designed to gain insights into the role of 3-monoiodothyronamine (T1AM) in the brain, where the amine was originally identified and characterized. Extensive deiodinase studies indicated that T1AM was derived from the T4 metabolite, reverse triiodothyronine (revT3), while functional studies provided well-confirmed evidence that T1AM has strong adrenergic-blocking effects. Because a state of adrenergic overactivity prevails when triiodothyronine (T3) concentrations become excessive, the possibility that T3's metabolic partner, revT3, might give rise to an antagonist of those T3 actions was thought to be reasonable. All T1AM studies thus far have required use of pharmacological doses. Therefore we considered that choosing a physiological site of action was a priority and focused on the locus coeruleus (LC), the major noradrenergic control center in the brain. Site-directed injections of T1AM into the LC elicited a significant, dose-dependent neuronal firing rate change in a subset of adrenergic neurons with an EC(50)=2.7 microM, a dose well within the physiological range. Further evidence for its physiological actions came from autoradiographic images obtained following intravenous carrier-free (125)I-labeled T1AM injection. These showed that the amine bound with high affinity to the LC and to other selected brain nuclei, each of which is both an LC target and a known T3 binding site. This new evidence points to a physiological role for T1AM as an endogenous adrenergic-blocking neuromodulator in the central noradrenergic system.
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Affiliation(s)
- Heinrich S Gompf
- Department of Neurology, Beth Israel Deaconess Medical Center, Boston, MA, USA.
| | - Joel H Greenberg
- Department of Neurology, University of Pennsylvania, Philadelphia, PA, USA
| | - Gary Aston-Jones
- Department of Neuroscience, Medical University of South Carolina, Charleston, SC, USA
| | - Alexandra G Ianculescu
- Department of Biochemistry and Biophysics, University of California, San Francisco, CA, USA
| | - Tom S Scanlan
- Department of Physiology and Pharmacology, Oregon Health and Science University, Portland, OR, USA
| | - Mary B Dratman
- Department of Medicine (Endocrinology), University of Pennsylvania, Philadelphia, PA, USA
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Khakpay R, Polster D, Köles L, Skorinkin A, Szabo B, Wirkner K, Illes P. Potentiation of the glutamatergic synaptic input to rat locus coeruleus neurons by P2X7 receptors. Purinergic Signal 2010; 6:349-59. [PMID: 21103218 DOI: 10.1007/s11302-010-9198-3] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2010] [Accepted: 07/14/2010] [Indexed: 12/21/2022] Open
Abstract
Locus coeruleus (LC) neurons in a rat brain slice preparation were superfused with a Mg(2+)-free and bicuculline-containing external medium. Under these conditions, glutamatergic spontaneous excitatory postsynaptic currents (sEPSCs) were recorded by means of the whole-cell patch-clamp method. ATP, as well as its structural analogue 2-methylthio ATP (2-MeSATP), both caused transient inward currents, which were outlasted by an increase in the frequency but not the amplitude of the sEPSCs. PPADS, but not suramin or reactive blue 2 counteracted both effects of 2-MeSATP. By contrast, α,β-methylene ATP (α,β-meATP), UTP and BzATP did not cause an inward current response. Of these latter agonists, only BzATP slightly facilitated the sEPSC amplitude and strongly potentiated its frequency. PPADS and Brilliant Blue G, as well as fluorocitric acid and aminoadipic acid prevented the activity of BzATP. Furthermore, BzATP caused a similar facilitation of the miniature (m)EPSC (recorded in the presence of tetrodotoxin) and sEPSC frequencies (recorded in its absence). Eventually, capsaicin augmented the frequency of the sEPSCs in a capsazepine-, but not PPADS-antagonizable, manner. In conclusion, the stimulation of astrocytic P2X7 receptors appears to lead to the outflow of a signalling molecule, which presynaptically increases the spontaneous release of glutamate onto LC neurons from their afferent fibre tracts. It is suggested, that the two algogenic compounds ATP and capsaicin utilise separate receptor systems to potentiate the release of glutamate and in consequence to increase the excitability of LC neurons.
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Samuels ER, Szabadi E. Functional neuroanatomy of the noradrenergic locus coeruleus: its roles in the regulation of arousal and autonomic function part I: principles of functional organisation. Curr Neuropharmacol 2010; 6:235-53. [PMID: 19506723 PMCID: PMC2687936 DOI: 10.2174/157015908785777229] [Citation(s) in RCA: 472] [Impact Index Per Article: 33.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2007] [Revised: 02/25/2008] [Accepted: 06/06/2008] [Indexed: 01/09/2023] Open
Abstract
The locus coeruleus (LC) is the major noradrenergic nucleus of the brain, giving rise to fibres innervating extensive areas throughout the neuraxis. Recent advances in neuroscience have resulted in the unravelling of the neuronal circuits controlling a number of physiological functions in which the LC plays a central role. Two such functions are the regulation of arousal and autonomic activity, which are inseparably linked largely via the involvement of the LC. The LC is a major wakefulness-promoting nucleus, resulting from dense excitatory projections to the majority of the cerebral cortex, cholinergic neurones of the basal forebrain, cortically-projecting neurones of the thalamus, serotoninergic neurones of the dorsal raphe and cholinergic neurones of the pedunculopontine and laterodorsal tegmental nucleus, and substantial inhibitory projections to sleep-promoting GABAergic neurones of the basal forebrain and ventrolateral preoptic area. Activation of the LC thus results in the enhancement of alertness through the innervation of these varied nuclei. The importance of the LC in controlling autonomic function results from both direct projections to the spinal cord and projections to autonomic nuclei including the dorsal motor nucleus of the vagus, the nucleus ambiguus, the rostroventrolateral medulla, the Edinger-Westphal nucleus, the caudal raphe, the salivatory nuclei, the paraventricular nucleus, and the amygdala. LC activation produces an increase in sympathetic activity and a decrease in parasympathetic activity via these projections. Alterations in LC activity therefore result in complex patterns of neuronal activity throughout the brain, observed as changes in measures of arousal and autonomic function.
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Affiliation(s)
- E R Samuels
- Psychopharmacology Section, University of Nottingham, Division of Psychiatry, Queen's Medical Centre, Nottingham, NG7 2UH, UK
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Kasparov S, Teschemacher AG. The use of viral gene transfer in studies of brainstem noradrenergic and serotonergic neurons. Philos Trans R Soc Lond B Biol Sci 2009; 364:2565-76. [PMID: 19651657 DOI: 10.1098/rstb.2009.0073] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
In contrast to some other neuronal populations, for example hippocampal or cortical pyramidal neurons, mechanisms of synaptic integration and transmitter release in central neurons that contain noradrenaline (NA) and serotonin (5HT) are not well understood. These cells, crucial for a wide range of autonomic and behavioural processes, have long un-myelinated axons with hundreds of varicosities where transmitters are synthesized and released. Both seem to signal mostly in 'volume transmission' mode. Very little is known about the rules that apply to this type of transmission in the brain and the factors that regulate the release of NA and 5HT. We discuss some of our published studies and more recent experiments in which viral vectors were used to investigate the physiology of these neuronal populations. We also focus on currently unresolved issues concerning the mechanism of volume transmission by NA and 5HT in the brain. We suggest that clarifying the role of astroglia in this process could be essential for our understanding of central noradrenergic and 5HT signalling.
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Affiliation(s)
- S Kasparov
- Department of Physiology and Pharmacology, Bristol Heart Institute, School of Medical Sciences, University of Bristol, , Bristol BS8 1TD, UK.
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De Martino B, Strange BA, Dolan RJ. Noradrenergic neuromodulation of human attention for emotional and neutral stimuli. Psychopharmacology (Berl) 2008; 197:127-36. [PMID: 18046544 PMCID: PMC2627987 DOI: 10.1007/s00213-007-1015-5] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/29/2007] [Accepted: 11/05/2007] [Indexed: 11/25/2022]
Abstract
INTRODUCTION Norepinephrine (NE) has a regulatory role in human attention. OBJECTIVE To examine its role in emotional modulation of attention, we used an attentional blink (AB) paradigm, in the context of psychopharmacological manipulation, where targets were either emotional or neutral items. RESULTS AND DISCUSSION We report behavioural evidence that beta-adrenergic blockade with propranolol impairs attention independent of target valence. Furthermore, this effect is centrally mediated as administration of the peripheral beta-adrenergic antagonist nadolol did not impair attention. By contrast, increasing NE tone, using the selective NE reuptake inhibitor reboxetine, improves detection of emotional stimuli. CONCLUSION In line with theoretical and animal models, these findings provide human behavioural evidence that the adrenergic system has a modulatory influence on selective attention that in some instances depends on item valence.
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Affiliation(s)
- Benedetto De Martino
- Functional Imaging Laboratory, Institute of Neurology, Wellcome Trust Centre for Neuroimaging, 12 Queen Square, London, WC1N 3BG, UK.
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Illes P, Nieber K, Fröhlich R, Nörenberg W. P2 purinoceptors and pyrimidinoceptors of catecholamine-producing cells and immunocytes. CIBA FOUNDATION SYMPOSIUM 2007; 198:110-25; discussion 125-9. [PMID: 8879821 DOI: 10.1002/9780470514900.ch6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
ATP is a neuronal (co)transmitter. In addition, both ATP and UTP may exit damaged cells and thereby function as extracellular signal molecules. The targets of signalling may be the P2 (for ATP and UTP) and P1 (for the degradation product adenosine) receptors of, for instance, neurons and immunocytes. UTP may also act at separate pyrimidinoceptors. Catecholamine-producing cells (adrenal chromaffin cells and peripheral and central noradrenergic neurons) possess P2X and P2Y purinoceptors. ATP appears to be a fast excitatory neuro-neuronal transmitter of the noradrenergic coeliac and locus coeruleus neurons. This effect is mediated by P2X purinoceptors. P2Y purinoceptor-mediated slow excitatory synaptic potentials have not yet been demonstrated either in the peripheral or central nervous system. On the other hand, after neuronal injury microglial cells (brain immunocytes) are engaged in a process called 'synaptic stripping', i.e. the displacement of synaptic boutons from the neuronal surface. During this process microglial cells are in direct contact with the (co)transmitter ATP. Activation of P2X, P2Z and P2Y purinoceptors results in an elevated intracellular Ca2+ concentration in microglia and macrophages. Various functions of these cells are regulated by intracellular Ca2+ (e.g. cytokine production, phagocytosis) and may therefore be modulated by nucleotides. Since neuronal damage leads to the transformation of microglial cells to macrophages and, at the same time, to the efflux of nucleotides from the damaged cells, the requirements for a modulatory interaction are fulfilled.
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Affiliation(s)
- P Illes
- Institut für Pharmakologie und Toxikologie der Universität Freiburg, Germany
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Ebner K, Singewald N. Stress-induced release of substance P in the locus coeruleus modulates cortical noradrenaline release. Naunyn Schmiedebergs Arch Pharmacol 2007; 376:73-82. [PMID: 17879086 DOI: 10.1007/s00210-007-0185-3] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2007] [Accepted: 08/20/2007] [Indexed: 10/22/2022]
Abstract
Several lines of evidence implicate the neuropeptide substance P (SP) in the modulation of emotional behavior. Interaction between SP and noradrenergic systems has been proposed to be important in the regulation of stress, depression, and anxiety mechanisms; however, most evidence so far is based on studies in unchallenged and/or anesthetized animals. Thus, by using a dual-probe microdialysis approach in freely moving animals, the aim of the present study was to investigate whether a relevant stressor can trigger the release of SP in the locus coeruleus (LC) and whether and how this response modulates noradrenaline (NA) transmission both in the LC and in the medial prefrontal cortex (mPFC), an important LC terminal region involved in emotional processing. While confirming previous reports that neurokinin 1 receptor (NK1R) antagonists activate cortical noradrenergic transmission under resting conditions, we present evidence that this interaction is opposite during stress challenge. Our results show that exposure to forced swimming considerably enhanced the release of SP and NA in the LC. Administration of a selective NK1R antagonist into the LC potentiated this NA response within the LC but abolished the stress-induced increase in NA release within the mPFC. These findings demonstrate stress-induced increase in endogenous extracellular SP levels within the LC exerting a facilitatory effect on the noradrenergic pathway to the mPFC. The attenuation of stress-induced hyperactivation of this pathway by NK1R antagonists, presumably via enhancing NA and autoinhibition in the LC, may contribute to the therapeutic efficacy of these drugs known to ameliorate symptoms of stress-related disorders.
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Affiliation(s)
- Karl Ebner
- Department of Pharmacology and Toxicology, Center for Molecular Biosciences Innsbruck, University of Innsbruck, Innsbruck, Austria.
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31
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Berrocoso E, Mico JA. In Vivo Effect of Venlafaxine on Locus Coeruleus Neurons: Role of Opioid, α2-Adrenergic, and 5-Hydroxytryptamine1A Receptors. J Pharmacol Exp Ther 2007; 322:101-7. [PMID: 17431134 DOI: 10.1124/jpet.107.120915] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
The locus coeruleus (LC) is involved in several neural pathways responsible for some somatic and emotional processes, such as pain and depression; its activity is regulated by several receptors, such as opioid, alpha(2)-adrenergic, and 5-hydroxytryptamine (5-HT)(1A) receptors. The present study investigates the in vivo effects of venlafaxine, an antidepressant with analgesic properties, on locus coeruleus neurons, and its modulation by opioid, alpha(2)-adrenergic, and 5-HT(1A) receptors. The results show that acute administration of venlafaxine produced a dose-dependent, complete inhibition of LC activity. This inhibitory effect was not reversed by the opioid receptor antagonist naloxone, but subsequent administration of idazoxan, an alpha(2)-adrenoceptor antagonist, did reverse it. The preadministration of the 5-HT(1A) receptor agonist 8-hydroxy-2-dipropylaminotetralin (8-OH-DPAT) (1 and 40 microg/kg) significantly enhanced the venlafaxine inhibitory effect, decreasing the ED(50) by 56 and 44%, respectively. A 14-day treatment with venlafaxine (40 mg/kg/day) induced a suppression of the firing activity of LC neurons. In these treated animals, venlafaxine produced an inhibitory effect similar to that in nontreated animals. This inhibitory effect was not reversed by naloxone, but it was reversed by idazoxan. In addition, the preadministration of 8-OH-DPAT (40 microg/kg) significantly enhanced the venlafaxine effect, decreasing the ED(50) by 60%. These results suggest that the effect of venlafaxine on LC neurons is modulated by alpha(2)-adrenergic and 5-HT(1A) receptors, and not by opioid receptors. These data could contribute to the further understanding of the antidepressant and analgesic mechanism of action of venlafaxine.
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Affiliation(s)
- Esther Berrocoso
- Pharmacology and Neuroscience Research Group, Department of Neuroscience (Pharmacology and Psychiatry), School of Medicine, University of Cádiz, Plaza Fragela 9, 11003 Cádiz, Spain
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Chiti Z, Teschemacher AG. Exocytosis of norepinephrine at axon varicosities and neuronal cell bodies in the rat brain. FASEB J 2007; 21:2540-50. [PMID: 17405853 DOI: 10.1096/fj.06-7342com] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Norepinephrine secretion from central neurons was widely assumed to occur by exocytosis, but the essential characteristics of this process remained unknown. We developed an approach to study it directly by amperometry using carbon fiber microelectrodes in organotypic rat brainstem slice cultures. Noradrenergic neurons from areas A1 and A2 were fluorescently labeled by an adenoviral vector with noradrenergic-specific promoter. Quantal events, consistent with exocytotic release of norepinephrine, were registered at noradrenergic axonal varicosities as well as at cell bodies. According to their charge integrals, events were grouped into two populations. The majority (approximately 40 fC) were compatible with full exocytotic fusion of small clear and dense core vesicles shown in previous morphometric studies. The quantal size distribution was modulated by treatment with reserpine and amitriptyline. In addition, much larger quantal events (>1 pC) occurred at predominantly axonal release sites. The time course of signals was severalfold faster than in adrenal chromaffin cells, suggesting profound differences in the release machinery between these cell types. Tetrodotoxin eliminated the majority of events, indicating that release was partially, but not entirely, action potential driven. In conclusion, central norepinephrine release has unique characteristics, distinguishing it from those of other monoaminergic cells in periphery and brain.
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Affiliation(s)
- Zohreh Chiti
- Department of Pharmacology, School of Medical Sciences, Bristol Heart Institute, University of Bristol, University Walk, Bristol BS8 1TD, UK
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33
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Sil’kis IG. A hypothetical mechanism for interactions between neuromodulators during paradoxical sleep. NEUROCHEM J+ 2007. [DOI: 10.1134/s1819712407010035] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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34
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Mendiguren A, Pineda J. CB(1) cannabinoid receptors inhibit the glutamatergic component of KCl-evoked excitation of locus coeruleus neurons in rat brain slices. Neuropharmacology 2006; 52:617-25. [PMID: 17070872 DOI: 10.1016/j.neuropharm.2006.09.004] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2006] [Revised: 09/12/2006] [Accepted: 09/13/2006] [Indexed: 11/17/2022]
Abstract
CB(1) cannabinoid receptors located at presynaptic sites suppress synaptic transmission in the rat brain. The aim of this work was to examine by single-unit extracellular techniques the effect of the synthetic cannabinoid receptor agonist WIN 55212-2 on KCl-evoked excitation of locus coeruleus neurons in rat brain slices. Short applications of KCl (30 mM) increased by 9-fold the firing rate of locus coeruleus cells. Perfusion with the GABA(A) receptor antagonist picrotoxin (100 microM) increased KCl-evoked effect, whereas NMDA and non-NMDA glutamate receptor antagonists (D-AP5 100 microM and CNQX 30 microM, respectively) were able to decrease KCl-evoked effect only in the presence of picrotoxin (100 microM). Bath application of WIN 55212-2 (10 microM) inhibited KCl-evoked effect; this inhibition was blocked by the CB(1) receptor antagonist AM 251 (1 microM). However, a lower concentration of WIN 55212-2 (1 microM) did not significantly change KCl effect. In the presence of picrotoxin (100 microM), perfusion with D-AP5 (100 microM) or CNQX (30 microM) blocked WIN 55212-2-induced inhibition, although picrotoxin (100 microM) itself failed to affect cannabinoid effect. In conclusion, GABAergic and glutamatergic components are both involved in KCl-evoked excitation of LC neurons, although CB(1) receptors only seem to inhibit the glutamatergic component of KCl effect in the locus coeruleus.
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Affiliation(s)
- Aitziber Mendiguren
- Department of Pharmacology, Faculty of Medicine, University of the Basque Country, Barrio Sarriena s/n, E-48940 Leioa, Bizkaia, Spain
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35
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Berrocoso E, Micó JA, Ugedo L. In vivo effect of tramadol on locus coeruleus neurons is mediated by alpha2-adrenoceptors and modulated by serotonin. Neuropharmacology 2006; 51:146-53. [PMID: 16730359 DOI: 10.1016/j.neuropharm.2006.03.013] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2005] [Revised: 03/10/2006] [Accepted: 03/10/2006] [Indexed: 11/29/2022]
Abstract
Tramadol is a centrally-acting analgesic endowed with opioid, noradrenergic and serotonergic properties. Various data suggest that, in addition to its analgesic effect, tramadol may have antidepressant and anxiolytic-like effects. This study investigates, through single-unit extracellular recording techniques, the in vivo effects of tramadol on locus coeruleus (LC) neurons and its possible effects on alpha(2)-adrenoceptors, opioid receptors and the 5-HT system. Tramadol produced a dose-dependent and complete inhibition of LC activity (ED(50)=2.1mg/kg). This inhibitory effect was prevented and reversed by the selective alpha(2)-adrenoceptor antagonist, idazoxan, but not by the opioid receptor antagonist, naloxone. The inhibition of the synthesis of 5-HT by p-chlorophenylalanine and the pre-administration of the 5-HT(1A) receptor agonist, 8-OH-DPAT at 40microg/kg, caused a significant potentiation of the tramadol effect decreasing the ED(50) by 53% and 67% respectively. Lower doses of 8-OH-DPAT, of 1 and 4microg/kg, did not significantly modify the tramadol effect. In summary, the results indicate that tramadol elicits an inhibitory effect on LC neurons in vivo through alpha(2)-adrenoceptors. Moreover, this effect is modulated by the 5-HT system and particularly by 5-HT(1A) receptors.
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Affiliation(s)
- Esther Berrocoso
- Pharmacology and Neuroscience Research Group, Department of Neuroscience (Pharmacology and Psychiatry), School of Medicine, University of Cádiz, Plaza Falla 9, E-11003 Cádiz, Spain
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36
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Andrews GD, Lavin A. Methylphenidate increases cortical excitability via activation of alpha-2 noradrenergic receptors. Neuropsychopharmacology 2006; 31:594-601. [PMID: 15999146 PMCID: PMC5509071 DOI: 10.1038/sj.npp.1300818] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Although methylphenidate (MPH), a catecholaminergic reuptake blocker, is prescribed for attention-deficit/hyperactivity disorder, there is a dearth of information regarding the cellular basis of its actions. To address this issue, we used whole-cell patch-clamp recordings to investigate the roles of various catecholamine receptors in MPH-induced changes in cortical neuron excitability. We bath-applied dopamine or noradrenaline receptor antagonists in combination with MPH to pyramidal cells located in deep layers of the infralimbic and prelimbic prefrontal cortices. Application of MPH (10 microM) by itself increased cortical cell excitability in slices obtained from juvenile rats. This MPH-mediated increase in excitability was lost when catecholamines were depleted with reserpine prior to recording, demonstrating the requirement for a presynaptic monoamine component. Antagonist studies further revealed that stimulation of alpha-2 noradrenergic receptors mediates the MPH-induced increase in intrinsic excitability. Dopamine D1 receptors played no observable role in the actions of MPH. We therefore propose that MPH is acting to increase catecholaminergic tone in the PFC, and thereby increases cortical excitability by mediating the disinhibition of pyramidal cells through mechanisms that may include activation of alpha-2 adrenoreceptors located in interneurons.
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Affiliation(s)
- Glenn D Andrews
- Department of Physiology and Neuroscience, Medical University of South Carolina, Charleston, SC, USA
| | - Antonieta Lavin
- Department of Physiology and Neuroscience, Medical University of South Carolina, Charleston, SC, USA
- Correspondence: Dr A Lavin, Department of Physiology and Neuroscience, Medical University of South Carolina, 173 Ashley Ave, Room 403 BSB, Charleston, SC 29425, USA, Tel: +1 843 792 6799, Fax: + 1 843 792 4423,
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37
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Nieuwenhuis S, Gilzenrat MS, Holmes BD, Cohen JD. The role of the locus coeruleus in mediating the attentional blink: a neurocomputational theory. J Exp Psychol Gen 2006; 134:291-307. [PMID: 16131265 DOI: 10.1037/0096-3445.134.3.291] [Citation(s) in RCA: 115] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The attentional blink refers to the transient impairment in perceiving the 2nd of 2 targets presented in close temporal proximity. In this article, the authors propose a neurobiological mechanism for this effect. The authors extend a recently developed computational model of the potentiating influence of the locus coeruleus-norepinephrine system on information processing and hypothesize that a refractoriness in the function of this system may account for the attentional blink. The model accurately simulates the time course of the attentional blink, including Lag 1 sparing. The theory also offers an account of the close relationship of the attentional blink to the electrophysiological P3 component. The authors report results from two behavioral experiments that support a critical prediction of their theory regarding the time course of Lag 1 sparing. Finally, the relationship between the authors' neurocomputational theory and existing cognitive theories of the attentional blink is discussed.
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38
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Nakai S, Matsunaga W, Ishida Y, Isobe KI, Shirokawa T. Effects of BDNF infusion on the axon terminals of locus coeruleus neurons of aging rats. Neurosci Res 2006; 54:213-9. [PMID: 16406148 DOI: 10.1016/j.neures.2005.12.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2005] [Revised: 12/06/2005] [Accepted: 12/06/2005] [Indexed: 12/29/2022]
Abstract
Using in vivo electrophysiological techniques and continuous local infusion methods, we examined the effects of brain-derived neurotrophic factor (BDNF) and its specific antibody (anti-BDNF) on the noradrenergic axon terminals of the locus coeruleus (LC) neurons in the frontal cortex of aging rats. Recently, we observed that LC neurons with multiple-threshold antidromic responses (multi-threshold LC neurons) increased critically between 15 and 17 months of age. To examine whether the BDNF is involved in this change occurred in the aging brain, we continuously infused BDNF into the frontal cortex for 14 days. Exogenous BDNF produced a marked increase in the multi-threshold LC neurons in the 13-month-old brain, accompanied with a decrease in threshold current. However, no morphological change in the noradrenergic axons was observed in the BDNF-infused cortex. In contrast, infusion of anti-BDNF led to a dose-dependent reduction of the multi-threshold LC neurons in the 19-month-old brain, accompanied with an increase in threshold current. These findings suggest that BDNF may contribute to functional changes in the presynaptic axon terminals of LC neurons in the aging brain.
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Affiliation(s)
- Sadamu Nakai
- Department of Basic Gerontology, National Center for Geriatrics and Gerontology, Obu 474-8522, Japan
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39
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Solis MM, Perkel DJ. Noradrenergic modulation of activity in a vocal control nucleus in vitro. J Neurophysiol 2005; 95:2265-76. [PMID: 16371453 PMCID: PMC1409810 DOI: 10.1152/jn.00836.2005] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Norepinephrine (NE) can profoundly modulate sensory processing, but its effect on motor function is less well understood. Birdsong is a learned behavior involving sensory and motor processes that are influenced by NE. A potential site of NE action is the robust nucleus of the arcopallium (RA): RA receives noradrenergic inputs and has adrenergic receptors, and it is a sensorimotor area instrumental to song production. We hypothesized that NE modulates RA neurons, and as a first test, we examined the effect of NE on RA activity in vitro. We recorded spontaneous activity extracellularly from isolated RA neurons in brain slices made from adult male zebra finches. These neurons exhibited regular tonic activity with firing rates averaging 5.5 Hz. Bath application of NE rapidly and reversibly decreased firing for the majority of neurons, to the extent that spontaneous activity was often abolished. This was likely a direct effect on the cell recorded, because it occurred with blockade of fast excitatory and inhibitory synaptic transmission or of all synaptic transmission. The NE-induced suppression involved alpha2-adrenergic receptors: yohimbine, an antagonist, completely reversed the suppression, and clonidine, an agonist, partially mimicked it. Perforated patch recordings revealed that NE induced a conductance increase in RA neurons; however, this did not prevent cells from firing when stimulated by afferents in HVC. For some neurons, NE application resulted in an increase in signal-to-noise ratio for spikes evoked by HVC stimulation. Thus NE could strongly modulate the spontaneous activity of RA cells, potentially enhancing signals relayed through RA.
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Affiliation(s)
- Michele M Solis
- Department of Biology, University of Washington, Seattle, WA 98195-6515, USA.
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40
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Nieuwenhuis S, Aston-Jones G, Cohen JD. Decision making, the P3, and the locus coeruleus-norepinephrine system. Psychol Bull 2005; 131:510-32. [PMID: 16060800 DOI: 10.1037/0033-2909.131.4.510] [Citation(s) in RCA: 1138] [Impact Index Per Article: 59.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Psychologists and neuroscientists have had a long-standing interest in the P3, a prominent component of the event-related brain potential. This review aims to integrate knowledge regarding the neural basis of the P3 and to elucidate its functional role in information processing. The authors review evidence suggesting that the P3 reflects phasic activity of the neuromodulatory locus coeruleus-norepinephrine (LC-NE) system. They discuss the P3 literature in the light of empirical findings and a recent theory regarding the information-processing function of the LC-NE phasic response. The theoretical framework emerging from this research synthesis suggests that the P3 reflects the response of the LC-NE system to the outcome of internal decision-making processes and the consequent effects of noradrenergic potentiation of information processing.
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Affiliation(s)
- Sander Nieuwenhuis
- Department of Cognitive Psychology, Vrije Universiteit, Amsterdam, the Netherlands.
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41
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Aston-Jones G, Cohen JD. An integrative theory of locus coeruleus-norepinephrine function: adaptive gain and optimal performance. Annu Rev Neurosci 2005; 28:403-50. [PMID: 16022602 DOI: 10.1146/annurev.neuro.28.061604.135709] [Citation(s) in RCA: 2578] [Impact Index Per Article: 135.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Historically, the locus coeruleus-norepinephrine (LC-NE) system has been implicated in arousal, but recent findings suggest that this system plays a more complex and specific role in the control of behavior than investigators previously thought. We review neurophysiological and modeling studies in monkey that support a new theory of LC-NE function. LC neurons exhibit two modes of activity, phasic and tonic. Phasic LC activation is driven by the outcome of task-related decision processes and is proposed to facilitate ensuing behaviors and to help optimize task performance (exploitation). When utility in the task wanes, LC neurons exhibit a tonic activity mode, associated with disengagement from the current task and a search for alternative behaviors (exploration). Monkey LC receives prominent, direct inputs from the anterior cingulate (ACC) and orbitofrontal cortices (OFC), both of which are thought to monitor task-related utility. We propose that these frontal areas produce the above patterns of LC activity to optimize utility on both short and long timescales.
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Affiliation(s)
- Gary Aston-Jones
- Laboratory of Neuromodulation and Behavior, Department of Psychiatry, University of Pennsylvania, Philadelphia, PA 19104, USA.
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42
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King EW, Audette K, Athman GA, Nguyen OXH, Sluka KA, Fairbanks CA. Transcutaneous electrical nerve stimulation activates peripherally located alpha-2A adrenergic receptors. Pain 2005; 115:364-373. [PMID: 15911163 DOI: 10.1016/j.pain.2005.03.027] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2004] [Revised: 01/31/2005] [Accepted: 03/14/2005] [Indexed: 11/29/2022]
Abstract
The alpha2A and alpha2C adrenergic receptor (AR) subtypes mediate antinociception when activated by the endogenous ligand norepinephrine. These receptors also produce antinociceptive synergy when activated concurrently with opioid receptor activation. The involvement of the opioid receptors in the mechanisms governing transcutaneous electrical nerve stimulation (TENS) has been well described. While spinal alpha-2 ARs do not appear to be involved in TENS antihyperalgesia in rats, the noradrenergic analgesic system also involves supraspinal and peripheral sites. Thus, a broader evaluation of the potential contribution of alpha-2 AR to TENS is warranted. The current study compared the antihyperalgesic efficacy of high (100 Hz) and low (4 Hz) frequency TENS in mutant mice lacking a functional alpha2A AR against their respective wildtype counterparts. The degree of secondary heat hyperalgesia induced by intra-articular injection of carrageenan/kaolin (3%) mixture did not differ among the experimental groups. However, the antihyperalgesia induced by both low and high frequency TENS was significantly diminished in alpha2A mutant mice compared to controls. The alpha2 adrenergic receptor selective antagonist, SK&F 86466, reversed TENS-mediated antihyperalgesia when delivered intra-articularly, but not when delivered intrathecally or intracerebroventricularly. These data suggest that peripheral alpha2 ARs contribute, in part, to TENS antihyperalgesia. This pharmacodynamic response is consistent with previous anatomical observations that alpha2A ARs are expressed on primary afferent neurons and macrophages near injured tissue.
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Affiliation(s)
- Ellen W King
- Department of Pharmaceutics, University of Minnesota, Minneapolis, MN 55455, USA Department of Pharmacology, University of Minnesota, Minneapolis, MN 55455, USA Department of Neuroscience, University of Minnesota, Minneapolis, MN 55455, USA Center for Pain Research, University of Minnesota, Minneapolis, MN 55455, USA Graduate Program in Physical Therapy and Rehabilitation Science Graduate Program, University of Iowa, Iowa City, IA 52242-1190, USA Graduate Program in Neuroscience Graduate Program, University of Iowa, Iowa City, IA 52242-1190, USA Graduate Program in Pain Research Program, University of Iowa, Iowa City, IA 52242-1190, USA Graduate Program in College of Medicine, University of Iowa, Iowa City, IA 52242-1190, USA
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43
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Jedema HP, Grace AA. Corticotropin-releasing hormone directly activates noradrenergic neurons of the locus ceruleus recorded in vitro. J Neurosci 2005; 24:9703-13. [PMID: 15509759 PMCID: PMC6730164 DOI: 10.1523/jneurosci.2830-04.2004] [Citation(s) in RCA: 137] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The neuropeptide corticotropin-releasing hormone (CRH) activates locus ceruleus (LC) neurons, thereby increasing norepinephrine levels throughout the CNS. Despite anatomical and physiological evidence for CRH innervation of the LC, the mechanism of CRH-evoked activation of LC neurons is unknown. Moreover, given the apparent absence of mRNA for CRH receptors in LC neurons, the exact location of action of CRH within the cerulear region is debated. Using in vitro intracellular recordings from rat brainstem, we examined whether CRH exerts a direct effect on LC neurons and which ionic currents are likely affected by CRH. We demonstrate that CRH dose-dependently increases the firing rate of LC neurons through a direct (TTX- and cadmium-insensitive) mechanism by decreasing a potassium conductance. The CRH-evoked activation of LC neurons is, at least in part, mediated by CRH1 receptors and a cAMP-dependent second messenger system. These data provide additional support that CRH functions as an excitatory neurotransmitter in the LC and the hypothesis that dysfunction of the CRH peptidergic and noradrenergic systems observed in patients with mood and anxiety disorders are functionally related.
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Affiliation(s)
- Hank P Jedema
- Department of Neuroscience, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, USA.
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44
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Shirokawa T, Ishida Y, Isobe KI. Age-related changes in the release and uptake activity of presynaptic axon terminals of rat locus coeruleus neurons. Neurosci Lett 2003; 344:212-4. [PMID: 12812843 DOI: 10.1016/s0304-3940(03)00463-4] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Age-related changes in the release and uptake activity of presynaptic axon terminals of rat locus coeruleus (LC) noradrenergic neurons were studied in the frontal cortex using an extracellular single unit recording technique in vivo. Clonidine, a selective alpha(2) adrenergic agonist, and nisoxetine, a selective noradrenaline uptake inhibitor, were infused locally into the frontal cortex to examine the effects of these drugs on release and uptake activities of the axon terminals of LC neurons. Although the infusion of clonidine produced a marked suppression of release, the effect did not change with age. Infusion of nisoxetine caused an inhibition of uptake, but the effect was attenuated in aged rats. These results suggest that the release activity mediated by the presynaptic autoreceptor did not change with age, but the uptake activity mediated by the NA transporter declined with age in the axon terminals of LC neurons.
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Affiliation(s)
- Tetsuya Shirokawa
- Laboratory of Physiology, Department of Basic Gerontology, National Institute for Longevity Sciences, 36-3, Morioka-cho, 474-8522, Obu, Japan.
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45
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Gilzenrat MS, Holmes BD, Rajkowski J, Aston-Jones G, Cohen JD. Simplified dynamics in a model of noradrenergic modulation of cognitive performance. Neural Netw 2002; 15:647-63. [PMID: 12371518 DOI: 10.1016/s0893-6080(02)00055-2] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Neurophysiological work in monkeys has shown that changes in tonic and stimulus-induced activity in the noradrenergic brainstem nucleus locus coeruleus (LC) are tightly correlated with fluctuations in behavioral performance in a visual discrimination task. Simulation work suggests transitions between observed modes of LC activity may be mediated by changes in the level of coherent firing among individual LC neurons. We have simplified this simulation by abstracting the LC to a simple, excitable system in two variables modeled after the FitzHugh-Nagumo relaxation oscillator. This abstracted LC simulates population-level dynamics of the nucleus relevant to its influence on behavior. Coherence within the nucleus was simulated as a single parameter which amplified external input to the abstracted LC while attenuating tonic, uncorrelated activity. Simulated results captured LC dynamics and their relationship with behavior observed in monkeys. Behavior was further simulated over a range of potential LC states not, as yet, directly observed. These results suggest a reverse sigmoidal relationship between false alarm rate and coherence, and a more complex, non-monotonic relationship between response time and coherence.
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Affiliation(s)
- Mark S Gilzenrat
- Center for the Study of Brain, Mind, and Behavior, Princeton University, NJ 08544, USA.
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Ishimatsu M, Kidani Y, Tsuda A, Akasu T. Effects of methylphenidate on the membrane potential and current in neurons of the rat locus coeruleus. J Neurophysiol 2002; 87:1206-12. [PMID: 11877494 DOI: 10.1152/jn.00463.2001] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Effects of methylphenidate (MPH), a therapeutic agent used in children presenting the attention deficit hyperactivity disorder (ADHD), on the membrane potential and current in neurons of the rat locus coeruleus (LC) were examined using intracellular and whole cell patch-clamp recording techniques. Application of MPH (30 microM) to artificial cerebrospinal fluid (ACSF) produced a hyperpolarizing response with amplitude of 12 +/- 1 mV (n = 29). Spontaneous firing of LC neurons was blocked during the MPH-induced hyperpolarization. Superfusion of LC neurons with ACSF containing 0 mM Ca(2+) and 11 mM Mg(2+) (Ca(2+)-free ACSF) produced a depolarizing response associated with an increase in spontaneous firing of the action potential. The MPH-induced hyperpolarization was blocked in Ca(2+)-free ACSF. Yohimbine (1 microM) and prazosin (10 microM), antagonists for alpha(2) and alpha(2B/2C) receptors, respectively, blocked the MPH-induced hyperpolarization in LC neurons. Tetrodotoxin (TTX, 1 microM) produced a partial depression of the MPH-induced hyperpolarization in LC neurons. Under the whole cell patch-clamp condition, MPH (30-300 microM) produced an outward current (I(MPH)) with amplitude of 110 +/- 6 pA (n = 17) in LC neurons. The I(MPH) was blocked by Co(2+) (1 mM). During prolonged application of MPH (300 microM for 45 min), the hyperpolarization gradually decreased in the amplitude and eventually disappeared, possibly because of depression of norepinephrine (NE) release from noradrenergic nerve terminals. At a low concentration (1 microM), MPH produced no outward current but consistently enhanced the outward current induced by NE. These results suggest that the MPH-induced response is mediated by NE via alpha(2B/2C)-adrenoceptors in LC neurons. I(MPH) was associated with an increase in the membrane conductance of LC neurons. The I(MPH) reversed its polarity at -102 +/- 6 mV (n = 8) in the ACSF. The reversal potential of I(MPH) was changed by 54 mV per decade change in the external K(+) concentration. Current-voltage relationship showed that the I(MPH) exhibited inward rectification. Ba(2+) (100 microM) suppressed the amplitude and the inward rectification of the I(MPH.) These results suggest that the I(MPH) is produced by activation of inward rectifier K(+) channels in LC neurons.
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Affiliation(s)
- Masaru Ishimatsu
- Department of Physiology, Kurume University School of Medicine, 67 Asahi-machi, Kurume 830-0011, Japan
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Osborne PB, Vidovic M, Chieng B, Hill CE, Christie MJ. Expression of mRNA and functional alpha(1)-adrenoceptors that suppress the GIRK conductance in adult rat locus coeruleus neurons. Br J Pharmacol 2002; 135:226-32. [PMID: 11786498 PMCID: PMC1573116 DOI: 10.1038/sj.bjp.0704453] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
1. Locus coeruleus neurons in adult rats express binding sites and mRNA for alpha(1)-adrenoceptors even though the depolarizing effect of alpha(1)-adrenoceptor agonists on neonatal neurons disappears during development. 2. In this study intracellular microelectrodes were used to record from locus coeruleus neurons in brain slices of adult rats and reverse transcription-polymerase chain reaction (RT - PCR) was used to investigate the mRNA expression of alpha(1)- and alpha(2)-adrenoceptors in juvenile and adult rats. 3. The alpha(1)-adrenoceptor agonist phenylephrine had no effect on the membrane conductance of locus coeruleus neurons (V(hold) -60 mV) but decreased the G protein coupled, inward rectifier potassium (GIRK) conductance induced by alpha(2)-adrenoceptor or mu-opioid agonists. The GIRK conductance induced by noradrenaline was increased in amplitude when alpha(1)-adrenoceptors were blocked with prazosin. 4. RT - PCR of total cellular RNA isolated from microdissected locus coeruleus tissue demonstrated strong mRNA expression of alpha(1a)-, alpha(1b)- and alpha(1d)-adrenoceptors in both juvenile and adult rats. However, only mRNA transcripts for the alpha(1b)-adrenoceptors were consistently detected in cytoplasmic samples taken from single locus coeruleus neurons of juvenile rats, suggesting that this subtype may be responsible for the physiological effects seen in juvenile rats. 5. Juvenile and adult locus coeruleus tissue expressed mRNA for the alpha(2a)- and alpha(2c)-adrenoceptors while the alpha(2b)-adrenoceptor was only weakly expressed in juveniles and was not detected in adults. 6. The results of this study show that alpha(1)-adrenoceptors expressed in adult locus coeruleus neurons function to suppress the GIRK conductance that is activated by mu-opioid and alpha(2)-adrenoceptors.
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MESH Headings
- Action Potentials/drug effects
- Adrenergic alpha-Agonists/pharmacology
- Age Factors
- Animals
- Electric Conductivity
- Gene Expression
- Locus Coeruleus/drug effects
- Locus Coeruleus/physiology
- Male
- Membrane Potentials/drug effects
- Models, Biological
- Neurons/drug effects
- Neurons/physiology
- Phenylephrine/pharmacology
- Potassium Channels/drug effects
- Potassium Channels/physiology
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- Rats
- Rats, Sprague-Dawley
- Receptors, Adrenergic, alpha-1/genetics
- Receptors, Adrenergic, alpha-1/physiology
- Receptors, Adrenergic, alpha-2/genetics
- Receptors, Adrenergic, alpha-2/physiology
- Receptors, Opioid, mu/physiology
- Reverse Transcriptase Polymerase Chain Reaction
- Signal Transduction
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Affiliation(s)
- Peregrine B Osborne
- Department of Pharmacology and The Medical Foundation, The University of Sydney D06, Sydney NSW 2006, Australia.
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Chen SY, Mao SP, Su CK, Wang SD, Chai CY. Activation of noradrenergic mechanism attenuates glutamate-induced vasopressor responses in the pons and medulla of cats in vivo. Prog Neuropsychopharmacol Biol Psychiatry 2001; 25:1063-81. [PMID: 11444678 DOI: 10.1016/s0278-5846(01)00170-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
1. Using anesthetized cats, the authors examined the noradrenergic modulation of the glutamate induced pressor and depressor responses in various brainstem areas, including pontine gigantocellular tegmental field (FTG), dorsomedial medulla (DM), rostral ventrolateral medulla (RVLM), and caudal ventrolateral medulla (CVLM). 2. Unilateral microinjection of L-glutamate (Glu, 3 nmol in 30 nL saline) into FTG, DM and RVLM produced an increase in systemic arterial pressure (SAP) and a decrease in heart rate (HR), while into CVLM produced decreases of SAP and HR. 3. Application of norepinephrine (NE) into the pressor areas (0.05 to 5 nmol) did not alter the resting SAP and HR, but significantly attenuated the Glu-induced pressor response with an order of potency: FTG > DM > RVLM. In the depressor CVLM, NE alone produced a dose-dependent decrease of resting SAP and HR, but did not affect the Glu-induced depressor responses. 4. The involvement of different adrenoceptor subtypes was further investigated by application of selective adrenoceptor agonists including phenylephrine (alpha1), clonidine (alpha2), and isoproterenol (beta). Responses to these agonists are similar to those elicited by NE, except that only alpha-adrenoceptor agonists could antagonize the Glu-induced pressor responses of the RVLM. 5. Our observations indicate that NE not only inhibits the pressor mechanisms in various brainstem areas but also elicits a direct depressor response in CVLM. These findings also suggest that NE acts more likely a neurotransmitter, rather than a modulator, in the CVLM.
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Affiliation(s)
- S Y Chen
- Graduate Institute of Life Sciences, National Defense Medical Center, Taipei, Taiwan, ROC
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Poelchen W, Sieler D, Wirkner K, Illes P. Co-transmitter function of ATP in central catecholaminergic neurons of the rat. Neuroscience 2001; 102:593-602. [PMID: 11226696 DOI: 10.1016/s0306-4522(00)00529-7] [Citation(s) in RCA: 66] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Intracellular recordings were made in a mid-pontine slice preparation of the rat brain containing the nucleus locus coeruleus. Focal electrical stimulation evoked biphasic synaptic potentials consisting of early depolarizing (d.p.s.p.) and late hyperpolarizing (i.p.s.p.) components. The alpha(2)-adrenoceptor antagonist idazoxan inhibited the i.p.s.p. without altering the d.p.s.p. All of the following experiments were carried out in the presence of kynurenic acid and picrotoxin to block the glutamatergic and GABAergic fractions of the d.p.s.p., respectively. Guanethidine, which is known to inhibit noradrenaline and ATP release from nerve terminals of postganglionic sympathetic nerves, depressed both the d.p.s.p. and the i.p.s.p. in a concentration-dependent manner. Damage of catecholaminergic nerve terminals by 6-hydroxydopamine also decreased both the d.p.s.p. and the i.p.s.p. The P2 receptor antagonist pyridoxal-phosphate-6-azophenyl-2',4'-disulphonic acid (PPADS) depressed the d.p.s.p., whereas the i.p.s.p. remained unaffected. The further application of PPADS did not increase the depression of the d.p.s.p. by guanethidine. Superfusion with the mixed alpha-adrenoceptor agonist noradrenaline or the selective P2 receptor agonist adenosine 5'-O-(2-thiodiphosphate) inhibited both the d.p.s.p. and the i.p.s.p. The inhibitory effects of these agonists were prevented by the respective antagonists idazoxan or suramin. In the presence of suramin noradrenaline failed to inhibit the residual d.p.s.p. Superfused noradrenaline potentiated rather than inhibited responses to pressure-applied alpha,beta-methylene-ATP; superfused adenosine 5'-O-(2-thiodiphosphate) did not interact with pressure-applied noradrenaline. In conclusion, we present electrophysiological evidence for the co-release of ATP and catecholamines in the CNS. At the cell somata of neurons in the locus coeruleus, noradrenaline and ATP activate inhibitory alpha(2)-adrenoceptors and excitatory P2 receptors, respectively. In addition, inhibitory presynaptic autoreceptors of the alpha(2) and P2 types appear to regulate release of the two co-transmitters.
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Affiliation(s)
- W Poelchen
- Rudolf-Boehm-Institut für Pharmakologie und Toxikologie, Universität Leipzig, Härtelstrasse 16-18, D-04107, Leipzig, Germany
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Kang YM, Ouyang W, Chen JY, Qiao JT, Dafny N. Norepinephrine modulates single hypothalamic arcuate neurons via alpha(1)and beta adrenergic receptors. Brain Res 2000; 869:146-57. [PMID: 10865069 DOI: 10.1016/s0006-8993(00)02380-5] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
The effects of norepinephrine (NE) on the electrophysiological activities of single hypothalamic arcuate neurons were studied using extracellular recording of 385 neurons from 169 brain slices in rats. The results showed that: (1) of 236 neurons selected randomly and tested with NE application, 137 (58.0%) were excited, 67 (28.4%) were inhibited, and 32 (13.6%) failed to respond; (2) substitution of low Ca(2+)-high Mg(2+) artificial cerebrospinal fluid (ACSF) for normal ACSF abolished the NE-induced inhibitory effect but failed to abolish the excitatory effect; (3) both the NE-induced excitatory and inhibitory effects were antagonized partly by phentolamine, prazosin, and propranolol but not by yohimbine; (4) naloxone and glibenclamide, a blocker of adenosine triphosphate-sensitive (K(ATP)) channels, blocked the NE-induced inhibitory effect; and (5) neurons that were inhibited by NE were also inhibited by morphine and cromakalim, an agonist of K(ATP) channels, and moreover, the morphine-induced inhibitory effect could be blocked by glibenclamide, while the cromakalim-induced inhibitory effect was not blocked by naloxone. These results imply that: (a) NE excites arcuate neurons through a mechanism that is insensitive to lowering the extracellular Ca(2+) suggesting a direct postsynaptic response through alpha(1)- and beta-adrenergic receptors, while NE inhibits cells through at least an inhibitory interneuron in arcuate and so is dependent on a Ca(2+)-sensitive presynaptic release mechanism; and (b) the inhibitory interneuron may be opioidergic, being excited first through alpha(1)- and beta-adrenergic receptors, after which the released opioids inhibit the neurons being recorded with an involvement of activation of K(ATP) channels. This possibility needs to be substantiated in much more detail.
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Affiliation(s)
- Y M Kang
- Department of Neurobiology, Shanxi Medical University, Shanxi 030001, Taiyuan, People's Republic of China
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