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Patel H. The role of the lateral septum in neuropsychiatric disease. J Neurosci Res 2022; 100:1422-1437. [PMID: 35443088 DOI: 10.1002/jnr.25052] [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: 07/08/2021] [Revised: 02/22/2022] [Accepted: 03/23/2022] [Indexed: 12/25/2022]
Abstract
The lateral septum (LS) is a structure in the midline of the brain that is interconnected with areas associated with stress and feeding. This review highlights the role of the LS in anxiety, depression, and eating disorders and their comorbidity. There is a prevailing view that the LS is anxiolytic. This review finds that the LS is both anxiolytic and anxiogenic. Furthermore, the LS can promote and inhibit feeding. Given these shared roles, the LS represents a common site for the comorbidity of neuropsychiatric disorders, and therefore a potential pharmacological target. This is crucial since currently available treatments are not always effective. Corticotrophin-releasing factor 2 antagonists are potential drugs for the treatment of anxiety and anorexia and require further research. Furthermore, other drugs currently in trials for binge eating, such as alpha-adrenergic agonists, may in fact promote food intake. It is hoped that the advancements in chemo- and optogenetic techniques will allow future studies to profile the specific neural connections of the LS and their function. This information could facilitate our understanding of the underlying mechanisms, and therefore pharmacological targets, of these psychiatric conditions.
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2
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Yang HM, Zhan LJ, Lin XQ, Chu CP, Qiu DL, Lan Y. Fentanyl Inhibits Air Puff-Evoked Sensory Information Processing in Mouse Cerebellar Neurons Recorded in vivo. Front Syst Neurosci 2020; 14:51. [PMID: 32848643 PMCID: PMC7417629 DOI: 10.3389/fnsys.2020.00051] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Accepted: 07/06/2020] [Indexed: 02/02/2023] Open
Abstract
Aim: To examine the effects of fentanyl, a potent mu-opioid receptor (MOR) agonist, on-air puff-evoked responses in Purkinje cells (PCs), and molecular layer interneurons (MLIs) using in vivo patch-clamp recordings in anesthetized mice. Methods: Male mice 6–8 weeks-old were anesthetized and fixed on a custom-made stereotaxic frame. The cerebellar surface was exposed and perfused with oxygenated artificial cerebrospinal fluid (ACSF). Patch-clamp recordings in the cell-attached mode were obtained from PCs and MLIs. Facial stimulation by air-puff of the ipsilateral whisker pad was performed through a pressurized injection system. Fentanyl citrate, CTOP, and H-89 dissolved in ACSF were perfused onto the cerebellar surface. Results: Fentanyl significantly inhibited the amplitude and area under the curve (AUC) of sensory stimulation-evoked inhibitory responses in PCs. Although fentanyl did not influence the frequency of simple spikes (SSs), it decreased the pause of SS. The IC50 of the fentanyl-induced suppression of the P1 response amplitude was 5.53 μM. The selective MOR antagonist CTOP abolished fentanyl-induced inhibitory responses in PCs. However, the application of CTOP alone increased the amplitude, AUC of P1, and the pause of SS. Notably, fentanyl significantly inhibited the tactile-evoked response of MLIs but did not affect their spontaneous firing. The fentanyl-induced decrease of inhibitory responses in PCs was partially prevented by a PKA inhibitor, H-89. Conclusions: These results suggest that fentanyl binds to MORs in MLIs to reduce GABAergic neurotransmission in MLI-PC projections and one potential mechanism is via modulation of the cAMP-PKA pathway.
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Affiliation(s)
- He-Min Yang
- Brain Science Research Center, Yanbian University, Yanji City, China.,Department of Physiology and Pathophysiology, College of Medicine, Yanbian University, Yanji City, China
| | - Li-Jie Zhan
- Brain Science Research Center, Yanbian University, Yanji City, China.,Department of Physiology and Pathophysiology, College of Medicine, Yanbian University, Yanji City, China
| | - Xue-Qin Lin
- Department of Physiology and Pathophysiology, College of Medicine, Yanbian University, Yanji City, China
| | - Chun-Ping Chu
- Brain Science Research Center, Yanbian University, Yanji City, China.,Department of Physiology and Pathophysiology, College of Medicine, Yanbian University, Yanji City, China
| | - De-Lai Qiu
- Brain Science Research Center, Yanbian University, Yanji City, China.,Department of Physiology and Pathophysiology, College of Medicine, Yanbian University, Yanji City, China
| | - Yan Lan
- Brain Science Research Center, Yanbian University, Yanji City, China.,Department of Physiology and Pathophysiology, College of Medicine, Yanbian University, Yanji City, China
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3
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Bendová Z, Pačesová D, Novotný J. The day-night differences in ERK1/2, GSK3β activity and c-Fos levels in the brain, and the responsiveness of various brain structures to morphine. J Comp Neurol 2020; 528:2471-2495. [PMID: 32170720 DOI: 10.1002/cne.24906] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2018] [Revised: 02/17/2020] [Accepted: 03/09/2020] [Indexed: 11/12/2022]
Abstract
As with other drugs or pharmaceuticals, opioids differ in their rewarding or analgesic effects depending on when they are applied. In the previous study, we have demonstrated the day/night difference in the sensitivity of the major circadian clock in the suprachiasmatic nucleus to a low dose of morphine, and showed the bidirectional effect of morphine on pERK1/2 and pGSK3β levels in the suprachiasmatic nucleus depending on the time of administration. The main aim of this study was to identify other brain structures that respond differently to morphine depending on the time of its administration. Using immunohistochemistry, we identified 44 structures that show time-of-day specific changes in c-Fos level and activity of ERK1/2 and GSK3β kinases in response to a single dose of 1 mg/kg morphine. Furthermore, comparison among control groups revealed the differences in the spontaneous levels of all markers with a generally higher level during the night, that is, in the active phase of the day. We thus provide further evidence for diurnal variations in the activity of brain regions outside the suprachiasmatic nucleus indicated by the temporal changes in the molecular substrate. We suggest that these changes are responsible for generating diurnal variation in the reward behavior or analgesic effect of opioid administration.
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Affiliation(s)
- Zdeňka Bendová
- Faculty of Science, Charles University, Prague, Czech Republic.,Department of Sleep Medicine and Chronobiology, National Institute of Mental Health, Klecany, Czech Republic
| | - Dominika Pačesová
- Faculty of Science, Charles University, Prague, Czech Republic.,Department of Sleep Medicine and Chronobiology, National Institute of Mental Health, Klecany, Czech Republic
| | - Jiří Novotný
- Faculty of Science, Charles University, Prague, Czech Republic
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4
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Guo S, Tang W, Hu Y, Chen Y, Gordon A, Li B, Li P. Enhancement of On-tissue Chemical Derivatization by Laser-Assisted Tissue Transfer for MALDI MS Imaging. Anal Chem 2019; 92:1431-1438. [PMID: 31800227 DOI: 10.1021/acs.analchem.9b04618] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The development of on-tissue chemical derivatization methods for matrix-assisted laser desorption/ionization (MALDI) mass spectrometry imaging (MSI) of small endogenous metabolites in tissues has attracted great attention for their advantages in improving detection sensitivity and ionization efficiency of poorly ionized and low abundant metabolites. Herein, a laser-assisted tissue transfer (LATT) technique was developed to enhance on-tissue derivatization of small molecules. Using a focused blue laser, a thin-layer tissue film (∼1 μm) was transferred to an acceptor slide from a 6 μm dry tissue section preliminarily coated with derivatization and matrix reagents. The acceptor slide with its ablated constituents was then imaged by MALDI MS. On-tissue chemical derivatization with amino-specific derivatization reagent 4-hydroxy-3-methoxycinnamaldehyde (CA) was carried out on LATT system. 20-235 folds increase in signal intensity for CA derivatized metabolites such as amino acids, neurotransmitters, and dipeptides were observed from rat brain tissues in comparison with conventional incubation-based derivatization. This technique was further extended to derivatize steroids with Girard reagent T (GirT). The remarkable derivatization efficiency can mainly be attributed to the minimization of ion suppression effects due to the reduced thickness of tissue section and endogenous components. Additionally, shorter derivatization time with no obvious metabolite delocalization was achieved using LATT method. These results demonstrate the advantages of LATT in the enhancement of on-tissue derivatization for the more specific and sensitive imaging of small metabolites in tissues with MALDI MS.
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Affiliation(s)
- Shuai Guo
- State Key Laboratory of Natural Medicines , China Pharmaceutical University , Nanjing , 210009 , China.,School of Basic Medicine and Clinical Pharmacy , China Pharmaceutical University , Nanjing , 211198 , China
| | - Weiwei Tang
- State Key Laboratory of Natural Medicines , China Pharmaceutical University , Nanjing , 210009 , China.,School of Traditional Chinese Pharmacy , China Pharmaceutical University , Nanjing , 211198 , China
| | - Yu Hu
- State Key Laboratory of Natural Medicines , China Pharmaceutical University , Nanjing , 210009 , China.,School of Traditional Chinese Pharmacy , China Pharmaceutical University , Nanjing , 211198 , China
| | - Yanwen Chen
- State Key Laboratory of Natural Medicines , China Pharmaceutical University , Nanjing , 210009 , China.,School of Traditional Chinese Pharmacy , China Pharmaceutical University , Nanjing , 211198 , China
| | - Andrew Gordon
- State Key Laboratory of Natural Medicines , China Pharmaceutical University , Nanjing , 210009 , China.,School of Traditional Chinese Pharmacy , China Pharmaceutical University , Nanjing , 211198 , China
| | - Bin Li
- State Key Laboratory of Natural Medicines , China Pharmaceutical University , Nanjing , 210009 , China.,School of Traditional Chinese Pharmacy , China Pharmaceutical University , Nanjing , 211198 , China
| | - Ping Li
- State Key Laboratory of Natural Medicines , China Pharmaceutical University , Nanjing , 210009 , China.,School of Traditional Chinese Pharmacy , China Pharmaceutical University , Nanjing , 211198 , China
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5
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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: 84] [Impact Index Per Article: 16.8] [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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6
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Leung LS, Ma J. Generalized seizures evoked by nucleus accumbens stimulation induced an opiate-mediated suppression of psychosis relevant behaviors. Behav Brain Res 2019; 356:365-370. [PMID: 30218680 DOI: 10.1016/j.bbr.2018.09.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2018] [Revised: 09/02/2018] [Accepted: 09/11/2018] [Indexed: 11/19/2022]
Abstract
We have previously demonstrated that kindling of the nucleus accumbens (NAc) induced psychosis relevant behaviors only after one, but not after five, stage-5 seizures, suggesting that five stage-5 NAc-evoked seizures antagonized psychosis relevant behaviors in rats. We hypothesized that brain opioid receptors are responsible for seizure-induced reduction of psychosis relevant behaviors in NAc kindled rats. Rats received NAc kindling until a stage-4 seizure was induced, after which naloxone, a non-specific opioid receptor antagonist, at dose of 1 or 10 mg/kg i.p., or saline (0.3 mL) i.p., was injected 15 min before each kindled seizure. Duration of afterdischarge (AD) was not significantly different among naloxone- and saline-treated groups. However, duration of postictal behavioral depression induced by a stage-5 seizure was significantly shorter in 10 mg/kg naloxone-treated than saline-treated rats, for long (>36 s) AD duration. When tested 3-4 days after five stage-5 seizures, 10 mg/kg naloxone-treated rats, as compared to saline-treated rats, showed a statistically significant loss of gating of hippocampal auditory evoked potentials, and significant reduction of startle response amplitude, but non-significant differences in prepulse inhibition and methamphetamine-induced locomotion. It is inferred that stage-5 seizures, by releasing endogenous opiates, contribute to postictal behavioral depression, and some long-term seizure-induced antipsychotic effects.
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Affiliation(s)
- L Stan Leung
- Department of Physiology and Pharmacology, The University of Western Ontario, London, N6A 5C1, Canada; Graduate Program of Neuroscience, The University of Western Ontario, London, N6A 5C1, Canada.
| | - Jingyi Ma
- Department of Physiology and Pharmacology, The University of Western Ontario, London, N6A 5C1, Canada
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7
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Shariatgorji M, Strittmatter N, Nilsson A, Källback P, Alvarsson A, Zhang X, Vallianatou T, Svenningsson P, Goodwin RJA, Andren PE. Simultaneous imaging of multiple neurotransmitters and neuroactive substances in the brain by desorption electrospray ionization mass spectrometry. Neuroimage 2016; 136:129-38. [PMID: 27155126 DOI: 10.1016/j.neuroimage.2016.05.004] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2015] [Revised: 04/26/2016] [Accepted: 05/02/2016] [Indexed: 02/07/2023] Open
Abstract
With neurological processes involving multiple neurotransmitters and neuromodulators, it is important to have the ability to directly map and quantify multiple signaling molecules simultaneously in a single analysis. By utilizing a molecular-specific approach, namely desorption electrospray ionization mass spectrometry imaging (DESI-MSI), we demonstrated that the technique can be used to image multiple neurotransmitters and their metabolites (dopamine, dihydroxyphenylacetic acid, 3-methoxytyramine, serotonin, glutamate, glutamine, aspartate, γ-aminobutyric acid, adenosine) as well as neuroactive drugs (amphetamine, sibutramine, fluvoxamine) and drug metabolites in situ directly in brain tissue sections. The use of both positive and negative ionization modes increased the number of identified molecular targets. Chemical derivatization by charge-tagging the primary amines of molecules significantly increased the sensitivity, enabling the detection of low abundant neurotransmitters and other neuroactive substances previously undetectable by MSI. The sensitivity of the imaging approach of neurochemicals has a great potential in many diverse applications in fields such as neuroscience, pharmacology, drug discovery, neurochemistry, and medicine.
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Affiliation(s)
- Mohammadreza Shariatgorji
- Biomolecular Imaging and Proteomics, National Resource for Mass Spectrometry Imaging, Department of Pharmaceutical Biosciences, Uppsala University, Box 591, SE-75124 Uppsala, Sweden
| | | | - Anna Nilsson
- Biomolecular Imaging and Proteomics, National Resource for Mass Spectrometry Imaging, Department of Pharmaceutical Biosciences, Uppsala University, Box 591, SE-75124 Uppsala, Sweden
| | - Patrik Källback
- Biomolecular Imaging and Proteomics, National Resource for Mass Spectrometry Imaging, Department of Pharmaceutical Biosciences, Uppsala University, Box 591, SE-75124 Uppsala, Sweden
| | - Alexandra Alvarsson
- Center for Molecular Medicine, Department of Neurology and Clinical Neuroscience, Karolinska Institutet and Karolinska University Hospital, 17176 Stockholm, Sweden
| | - Xiaoqun Zhang
- Center for Molecular Medicine, Department of Neurology and Clinical Neuroscience, Karolinska Institutet and Karolinska University Hospital, 17176 Stockholm, Sweden
| | - Theodosia Vallianatou
- Biomolecular Imaging and Proteomics, National Resource for Mass Spectrometry Imaging, Department of Pharmaceutical Biosciences, Uppsala University, Box 591, SE-75124 Uppsala, Sweden
| | - Per Svenningsson
- Center for Molecular Medicine, Department of Neurology and Clinical Neuroscience, Karolinska Institutet and Karolinska University Hospital, 17176 Stockholm, Sweden
| | | | - Per E Andren
- Biomolecular Imaging and Proteomics, National Resource for Mass Spectrometry Imaging, Department of Pharmaceutical Biosciences, Uppsala University, Box 591, SE-75124 Uppsala, Sweden.
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8
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Esteve C, Tolner EA, Shyti R, van den Maagdenberg AMJM, McDonnell LA. Mass spectrometry imaging of amino neurotransmitters: a comparison of derivatization methods and application in mouse brain tissue. Metabolomics 2016; 12:30. [PMID: 26793043 PMCID: PMC4705126 DOI: 10.1007/s11306-015-0926-0] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/26/2015] [Accepted: 09/19/2015] [Indexed: 12/12/2022]
Abstract
The detection of small polar compounds such as amino neurotransmitters by MALDI mass spectrometry imaging has been hindered by low-detection sensitivity and background interferences. Recently, several of on-tissue chemical derivatization strategies have been independently reported that enable their detection. Here, we present a comparison between these methods, and demonstrate the visualization of the distributions of up to 23 amino metabolites in tissue. We applied this methodology to detect alterations of these compounds after inducing an experimental cortical spreading depression in mouse brain, which causes profound transient alterations in key neurotransmitters in one hemisphere and is relevant for migraine and various other neurological disorders.
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Affiliation(s)
- Clara Esteve
- Center for Proteomics and Metabolomics, Leiden University Medical Center, Einthovenweg 20, 2333 ZC Leiden, The Netherlands
| | - Else A. Tolner
- Department of Neurology, Leiden University Medical Center, Leiden, The Netherlands
| | - Reinald Shyti
- Department of Human Genetics, Leiden University Medical Center, Leiden, The Netherlands
| | - Arn M. J. M. van den Maagdenberg
- Department of Neurology, Leiden University Medical Center, Leiden, The Netherlands
- Department of Human Genetics, Leiden University Medical Center, Leiden, The Netherlands
| | - Liam A. McDonnell
- Center for Proteomics and Metabolomics, Leiden University Medical Center, Einthovenweg 20, 2333 ZC Leiden, The Netherlands
- Fondazione Pisana per la Scienza ONLUS, Pisa, Italy
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9
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Glutamic acid decarboxylase isoform distribution in transgenic mouse septum: an anti-GFP immunofluorescence study. Anat Sci Int 2015; 91:398-406. [PMID: 26643381 DOI: 10.1007/s12565-015-0316-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2015] [Accepted: 11/08/2015] [Indexed: 10/22/2022]
Abstract
The septum is a basal forebrain region located between the lateral ventricles in rodents. It consists of lateral and medial divisions. Medial septal projections regulate hippocampal theta rhythm whereas lateral septal projections are involved in processes such as affective functions, memory formation, and behavioral responses. Gamma-aminobutyric acidergic neurons of the septal region possess the 65 and 67 isoforms of the enzyme glutamic acid decarboxylase. Although data on the glutamic acid decarboxylase isoform distribution in the septal region generally appears to indicate glutamic acid decarboxylase 67 dominance, different studies have given inconsistent results in this regard. The aim of this study was therefore to obtain information on the distributions of both of these glutamic acid decarboxylase isoforms in the septal region in transgenic mice. Two animal groups of glutamic acid decarboxylase-green fluorescent protein knock-in transgenic mice were utilized in the experiment. Brain sections from the region were taken for anti-green fluorescent protein immunohistochemistry in order to obtain estimated quantitative data on the number of gamma-aminobutyric acidergic neurons. Following the immunohistochemical procedures, the mean numbers of labeled cells in the lateral and medial septal nuclei were obtained for the two isoform groups. Statistical analysis yielded significant results which indicated that the 65 isoform of glutamic acid decarboxylase predominates in both lateral and medial septal nuclei (unpaired two-tailed t-test p < 0.0001 for LS, p < 0.01 for MS). This study is the first to reveal the dominance of glutamic acid decarboxylase isoform 65 in the septal region in glutamic acid decarboxylase-green fluorescent protein transgenic mice.
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10
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Hoffmann LC, Cicchese JJ, Berry SD. Harnessing the power of theta: natural manipulations of cognitive performance during hippocampal theta-contingent eyeblink conditioning. Front Syst Neurosci 2015; 9:50. [PMID: 25918501 PMCID: PMC4394696 DOI: 10.3389/fnsys.2015.00050] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2015] [Accepted: 03/12/2015] [Indexed: 12/17/2022] Open
Abstract
Neurobiological oscillations are regarded as essential to normal information processing, including coordination and timing of cells and assemblies within structures as well as in long feedback loops of distributed neural systems. The hippocampal theta rhythm is a 3–12 Hz oscillatory potential observed during cognitive processes ranging from spatial navigation to associative learning. The lower range, 3–7 Hz, can occur during immobility and depends upon the integrity of cholinergic forebrain systems. Several studies have shown that the amount of pre-training theta in the rabbit strongly predicts the acquisition rate of classical eyeblink conditioning and that impairment of this system substantially slows the rate of learning. Our lab has used a brain-computer interface (BCI) that delivers eyeblink conditioning trials contingent upon the explicit presence or absence of hippocampal theta. A behavioral benefit of theta-contingent training has been demonstrated in both delay and trace forms of the paradigm with a two- to four-fold increase in learning speed. This behavioral effect is accompanied by enhanced amplitude and synchrony of hippocampal local field potential (LFP)s, multi-unit excitation, and single-unit response patterns that depend on theta state. Additionally, training in the presence of hippocampal theta has led to increases in the salience of tone-induced unit firing patterns in the medial prefrontal cortex, followed by persistent multi-unit activity during the trace interval. In cerebellum, rhythmicity and precise synchrony of stimulus time-locked LFPs with those of hippocampus occur preferentially under the theta condition. Here we review these findings, integrate them into current models of hippocampal-dependent learning and suggest how improvement in our understanding of neurobiological oscillations is critical for theories of medial temporal lobe processes underlying intact and pathological learning.
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Affiliation(s)
- Loren C Hoffmann
- Center for Learning and Memory, University of Texas Austin, TX, USA
| | - Joseph J Cicchese
- Department of Psychology and Center for Neuroscience, Miami University Oxford, OH, USA
| | - Stephen D Berry
- Department of Psychology and Center for Neuroscience, Miami University Oxford, OH, USA
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11
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Shariatgorji M, Nilsson A, Goodwin RJA, Källback P, Schintu N, Zhang X, Crossman AR, Bezard E, Svenningsson P, Andren PE. Direct targeted quantitative molecular imaging of neurotransmitters in brain tissue sections. Neuron 2014; 84:697-707. [PMID: 25453841 DOI: 10.1016/j.neuron.2014.10.011] [Citation(s) in RCA: 164] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/29/2014] [Indexed: 01/10/2023]
Abstract
Current neuroimaging techniques have very limited abilities to directly identify and quantify neurotransmitters from brain sections. We have developed a molecular-specific approach for the simultaneous imaging and quantitation of multiple neurotransmitters, precursors, and metabolites, such as tyrosine, tryptamine, tyramine, phenethylamine, dopamine, 3-methoxytyramine, serotonin, GABA, glutamate, acetylcholine, and L-alpha-glycerylphosphorylcholine, in histological tissue sections at high spatial resolutions. The method is employed to directly measure changes in the absolute and relative levels of neurotransmitters in specific brain structures in animal disease models and in response to drug treatments, demonstrating the power of mass spectrometry imaging in neuroscience.
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Affiliation(s)
- Mohammadreza Shariatgorji
- Biomolecular Imaging and Proteomics, National Center for Mass Spectrometry Imaging, Department of Pharmaceutical Biosciences, Uppsala University, P.O. Box 591 BMC, 75124 Uppsala, Sweden
| | - Anna Nilsson
- Biomolecular Imaging and Proteomics, National Center for Mass Spectrometry Imaging, Department of Pharmaceutical Biosciences, Uppsala University, P.O. Box 591 BMC, 75124 Uppsala, Sweden
| | - Richard J A Goodwin
- Biomolecular Imaging and Proteomics, National Center for Mass Spectrometry Imaging, Department of Pharmaceutical Biosciences, Uppsala University, P.O. Box 591 BMC, 75124 Uppsala, Sweden; AstraZeneca R&D, Alderley Park, Macclesfield, Cheshire SK10 4TF, UK
| | - Patrik Källback
- Biomolecular Imaging and Proteomics, National Center for Mass Spectrometry Imaging, Department of Pharmaceutical Biosciences, Uppsala University, P.O. Box 591 BMC, 75124 Uppsala, Sweden
| | - Nicoletta Schintu
- Center for Molecular Medicine, Department of Neurology and Clinical Neuroscience, Karolinska Institutet and Karolinska University Hospital, 17176 Stockholm, Sweden
| | - Xiaoqun Zhang
- Center for Molecular Medicine, Department of Neurology and Clinical Neuroscience, Karolinska Institutet and Karolinska University Hospital, 17176 Stockholm, Sweden
| | - Alan R Crossman
- Faculty of Life Sciences, University of Manchester, Manchester M13 9PL, UK
| | - Erwan Bezard
- Université de Bordeaux, Institut des Maladies Neurodégénératives, UMR 5293 Bordeaux, France
| | - Per Svenningsson
- Center for Molecular Medicine, Department of Neurology and Clinical Neuroscience, Karolinska Institutet and Karolinska University Hospital, 17176 Stockholm, Sweden
| | - Per E Andren
- Biomolecular Imaging and Proteomics, National Center for Mass Spectrometry Imaging, Department of Pharmaceutical Biosciences, Uppsala University, P.O. Box 591 BMC, 75124 Uppsala, Sweden.
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12
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Keimpema E, Zheng K, Barde SS, Berghuis P, Dobszay MB, Schnell R, Mulder J, Luiten PGM, Xu ZD, Runesson J, Langel Ü, Lu B, Hökfelt T, Harkany T. GABAergic terminals are a source of galanin to modulate cholinergic neuron development in the neonatal forebrain. ACTA ACUST UNITED AC 2013; 24:3277-88. [PMID: 23897649 DOI: 10.1093/cercor/bht192] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The distribution and (patho-)physiological role of neuropeptides in the adult and aging brain have been extensively studied. Galanin is an inhibitory neuropeptide that can coexist with γ-aminobutyric acid (GABA) in the adult forebrain. However, galanin's expression sites, mode of signaling, impact on neuronal morphology, and colocalization with amino acid neurotransmitters during brain development are less well understood. Here, we show that galaninergic innervation of cholinergic projection neurons, which preferentially express galanin receptor 2 (GalR2) in the neonatal mouse basal forebrain, develops by birth. Nerve growth factor (NGF), known to modulate cholinergic morphogenesis, increases GalR2 expression. GalR2 antagonism (M871) in neonates reduces the in vivo expression and axonal targeting of the vesicular acetylcholine transporter (VAChT), indispensable for cholinergic neurotransmission. During cholinergic neuritogenesis in vitro, GalR2 can recruit Rho-family GTPases to induce the extension of a VAChT-containing primary neurite, the prospective axon. In doing so, GalR2 signaling dose-dependently modulates directional filopodial growth and antagonizes NGF-induced growth cone differentiation. Galanin accumulates in GABA-containing nerve terminals in the neonatal basal forebrain, suggesting its contribution to activity-driven cholinergic development during the perinatal period. Overall, our data define the cellular specificity and molecular complexity of galanin action in the developing basal forebrain.
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Affiliation(s)
- Erik Keimpema
- Department of Neuroscience, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm SE-17177, Sweden
| | | | | | - Paul Berghuis
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm SE-17177, Sweden
| | - Márton B Dobszay
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm SE-17177, Sweden
| | - Robert Schnell
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm SE-17177, Sweden
| | - Jan Mulder
- Department of Neuroscience, Science for Life Laboratory, Royal Institute of Technology, Stockholm SE-17121, Sweden
| | - Paul G M Luiten
- Department of Molecular Neurobiology, University of Groningen, Groningen NL-9747 AG, The Netherlands
| | - Zhiqing David Xu
- Department of Neuroscience, Beijing Institute for Neuroscience, Beijing Center for Neural Regeneration and Repairing, Department of Neurobiology, Capital Medical University, Beijing 100069, China
| | - Johan Runesson
- Department of Neurochemistry, Stockholm University, Stockholm SE-10691, Sweden and
| | - Ülo Langel
- Department of Neurochemistry, Stockholm University, Stockholm SE-10691, Sweden and
| | - Bai Lu
- R&D China, GlaxoSmithKline, Pudong, Shanghai 201203, China
| | | | - Tibor Harkany
- Department of Neuroscience, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm SE-17177, Sweden
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13
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Milner TA, Burstein SR, Marrone GF, Khalid S, Gonzalez AD, Williams TJ, Schierberl KC, Torres-Reveron A, Gonzales KL, McEwen BS, Waters EM. Stress differentially alters mu opioid receptor density and trafficking in parvalbumin-containing interneurons in the female and male rat hippocampus. Synapse 2013; 67:757-72. [PMID: 23720407 DOI: 10.1002/syn.21683] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2013] [Accepted: 05/10/2013] [Indexed: 12/21/2022]
Abstract
Stress differentially affects hippocampal-dependent learning relevant to addiction and morphology in male and female rats. Mu opioid receptors (MORs), which are located in parvalbumin (PARV)-containing GABAergic interneurons and are trafficked in response to changes in the hormonal environment, play a critical role in promoting principal cell excitability and long-term potentiation. Here, we compared the effects of acute and chronic immobilization stress (AIS and CIS) on MOR trafficking in PARV-containing neurons in the hilus of the dentate gyrus in female and male rats using dual label immunoelectron microscopy. Following AIS, the density of MOR silver-intensified gold particles (SIGs) in the cytoplasm of PARV-labeled dendrites was significantly reduced in females (estrus stage). Conversely, AIS significantly increased the proportion of cytoplasmic MOR SIGs in PARV-labeled dendrites in male rats. CIS significantly reduced the number of PARV-labeled neurons in the dentate hilus of males but not females. However, MOR/PARV-labeled dendrites and terminals were significantly smaller in CIS females, but not males, compared with controls. Following CIS, the density of cytoplasmic MOR SIGs increased in PARV-labeled dendrites and terminals in females. Moreover, the proportion of near-plasmalemmal MOR SIGs relative to total decreased in large PARV-labeled dendrites in females. After CIS, no changes in the density or trafficking of MOR SIGs were seen in PARV-labeled dendrites or terminals in males. These data show that AIS and CIS differentially affect available MOR pools in PARV-containing interneurons in female and male rats. Furthermore, they suggest that CIS could affect principal cell excitability in a manner that maintains learning processes in females but not males.
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Affiliation(s)
- Teresa A Milner
- Brain and Mind Research Institute, Weill Cornell Medical College, 407 East 61st Street, New York, New York, 10065; Harold and Margaret Milliken Hatch Laboratory of Neuroendocrinology, The Rockefeller University, 1230 York Avenue, New York, New York, 10065
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14
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Peciña M, Stohler CS, Zubieta JK. Role of μ-opioid system in the formation of memory of placebo responses. Mol Psychiatry 2013; 18:135-7. [PMID: 22430673 PMCID: PMC4152848 DOI: 10.1038/mp.2012.16] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The endogenous opioid system is centrally involved in short-term placebo analgesic effects, but its potential regulation of memory and learning circuits, critical for the sustainability of placebo responses, has not been explored. Here we examined the recall of analgesic effects after placebo administration as a function of its initial capacity to activate μ-opioid neurotransmission. Memories of therapeutic/adverse responses 24 hours after placebo administration were associated with differences in μ-opioid neurotransmission in the Papez circuit, VTA, amygdala and septum. These data suggests that μ-opioid neurotransmission is involved in the recall of therapeutic benefit, providing a framework to understand stimulus learning and long-term therapeutic effect associations.
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Affiliation(s)
- Marta Peciña
- Molecular and Behavioral Neuroscience Institute, University of Michigan, Ann Arbor, MI, USA
| | - Christian S. Stohler
- School of Dentistry, University of Maryland, Baltimore, MD, USA,To whom correspondence should be addressed: Jon-Kar Zubieta, MD, PhD, University of Michigan, 205 Zina Pitcher Place, Ann Arbor, MI 48109-0720, Phone: 734-763-6843, Fax: 734-647-4130,
| | - Jon-Kar Zubieta
- Molecular and Behavioral Neuroscience Institute, University of Michigan, Ann Arbor, MI, USA,Department of Radiology, Medical School, University of Michigan, Ann Arbor, MI, USA
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15
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Therapeutic potential of histaminergic compounds in the treatment of addiction and drug-related cognitive disorders. Behav Brain Res 2013; 237:357-68. [DOI: 10.1016/j.bbr.2012.09.025] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2012] [Revised: 09/13/2012] [Accepted: 09/16/2012] [Indexed: 12/21/2022]
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16
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Varga V, Hangya B, Kránitz K, Ludányi A, Zemankovics R, Katona I, Shigemoto R, Freund TF, Borhegyi Z. The presence of pacemaker HCN channels identifies theta rhythmic GABAergic neurons in the medial septum. J Physiol 2008; 586:3893-915. [PMID: 18565991 DOI: 10.1113/jphysiol.2008.155242] [Citation(s) in RCA: 90] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
The medial septum (MS) is an indispensable component of the subcortical network which synchronizes the hippocampus at theta frequency during specific stages of information processing. GABAergic neurons exhibiting highly regular firing coupled to the hippocampal theta rhythm are thought to form the core of the MS rhythm-generating network. In recent studies the hyperpolarization-activated, cyclic nucleotide-gated non-selective cation (HCN) channel was shown to participate in theta synchronization of the medial septum. Here, we tested the hypothesis that HCN channel expression correlates with theta modulated firing behaviour of MS neurons by a combined anatomical and electrophysiological approach. HCN-expressing neurons represented a subpopulation of GABAergic cells in the MS partly overlapping with parvalbumin (PV)-containing neurons. Rhythmic firing in the theta frequency range was characteristic of all HCN-expressing neurons. In contrast, only a minority of HCN-negative cells displayed theta related activity. All HCN cells had tight phase coupling to hippocampal theta waves. As a group, PV-expressing HCN neurons had a marked bimodal phase distribution, whereas PV-immunonegative HCN neurons did not show group-level phase preference despite significant individual phase coupling. Microiontophoretic blockade of HCN channels resulted in the reduction of discharge frequency, but theta rhythmic firing was perturbed only in a few cases. Our data imply that HCN-expressing GABAergic neurons provide rhythmic drive in all phases of the hippocampal theta activity. In most MS theta cells rhythm genesis is apparently determined by interactions at the level of the network rather than by the pacemaking property of HCN channels alone.
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Affiliation(s)
- Viktor Varga
- Department of Cell and Network Neurobiology, Institute of Experimental Medicine of the Hungarian Academy of Sciences; Szigony u. 43. Budapest, 1083 Hungary.
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17
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Liu Q, Puche AC, Wang JB. Distribution and Expression of Protein Kinase C Interactive Protein (PKCI/HINT1) in Mouse Central Nervous System (CNS). Neurochem Res 2008; 33:1263-76. [DOI: 10.1007/s11064-007-9578-4] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2007] [Accepted: 12/20/2007] [Indexed: 11/30/2022]
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18
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Taraschenko OD, Rubbinaccio HY, Shulan JM, Glick SD, Maisonneuve IM. Morphine-induced changes in acetylcholine release in the interpeduncular nucleus and relationship to changes in motor behavior in rats. Neuropharmacology 2007; 53:18-26. [PMID: 17544456 PMCID: PMC2025684 DOI: 10.1016/j.neuropharm.2007.04.010] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2006] [Revised: 04/03/2007] [Accepted: 04/04/2007] [Indexed: 11/19/2022]
Abstract
Owing to multiple anatomical connections and functional interactions between the habenulo-interpeduncular and the mesolimbic pathways, it has been proposed that these systems could together mediate the reinforcing properties of addictive drugs. 18-Methoxycoronaridine, an agent that reduces morphine self-administration and attenuates dopamine sensitization in the nucleus accumbens in response to repeated morphine, has been shown to produce these effects by acting in the medial habenula and interpeduncular nucleus. Acetylcholine, one of the predominant neurotransmitters in the interpeduncular nucleus, may be a major determinant of these interactions. To determine if and how morphine acts in the interpeduncular nucleus, the effects of acute and repeated administration of morphine on extracellular acetylcholine levels in this brain area were assessed. In addition, the motor behavior of rats receiving repeated morphine administration was monitored during microdialysis sessions. Acutely, morphine produced a biphasic effect on extracellular acetylcholine levels in the interpeduncular nucleus such that low and high doses of morphine (i.e., 5 and 20mg/kg i.p.) significantly increased and decreased acetylcholine levels, respectively. Repeated administration of the same doses of morphine resulted in tolerance to the inhibitory but not to the stimulatory effects; tolerance was accompanied by sensitization to morphine-induced changes in locomotor activity and stereotypic behavior. The latter results suggest that tolerance to morphine's effect on the cholinergic habenulo-interpeduncular pathway is related to its sensitizing effects on the mesostriatal dopaminergic pathways.
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Affiliation(s)
- Olga D Taraschenko
- Center for Neuropharmacology and Neuroscience, Albany Medical College, 47 New Scotland Avenue, Albany, NY 12208, USA.
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19
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Abstract
Opiate drugs alter cognitive performance and influence hippocampal excitability, including long-term potentiation (LTP) and seizure activity. The dentate gyrus (DG) contains two major opioid peptides, enkephalins and dynorphins, which have opposing effects on excitability. Enkephalins preferentially bind to delta- and mu-opioid receptors (DORs and MORs) while dynorphins preferentially bind to kappa-opioid receptors (KORs). Opioid receptors can also be activated by exogenous opiate drugs such as the MOR agonist morphine. Enkephalins are contained in the mossy fiber pathway, in the lateral perforant path (PP) and in scattered GABAergic interneurons. MORs and DORs are predominantly in distinct subpopulations of GABAergic interneurons known to inhibit granule cells, and are present at low levels within granule cells. MOR and DOR agonists increase excitability and facilitate LTP in the molecular layer. Anatomical and physiological evidence is consistent with somatodendritic and axon terminal targeting of both MORs and DORs. Dynorphins are in the granule cells, most abundantly in mossy fibers but also in dendrites. KORs have been localized to granule cell mossy fibers, supramammillary afferents to granule cells, and PP terminals. KOR agonists, including endogenous dynorphins, diminish the induction of LTP. Recent evidence indicates that opiates and opioids also modulate other processes in the hippocampal formation, including adult neurogenesis, the actions of gonadal hormones, and development of neonatal transmitter systems.
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Affiliation(s)
- Carrie T Drake
- Division of Neurobiology, Department of Neurology and Neuroscience, Weill-Cornell Medical College, 411 East 69th Street, New York, NY 10021, USA
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20
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Zarrindast MR, Moghimi M, Rostami P, Rezayof A. Histaminergic receptors of medial septum and conditioned place preference: D1 dopamine receptor mechanism. Brain Res 2006; 1109:108-16. [PMID: 16828718 DOI: 10.1016/j.brainres.2006.06.024] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2005] [Revised: 06/06/2006] [Accepted: 06/12/2006] [Indexed: 10/24/2022]
Abstract
In the present study, the effects of intra-medial septum injections of histamine and/or the histamine H1 or H2 receptor antagonists on the acquisition of conditioned place preference (CPP) in male Wistar rats have been investigated. Our data showed that the conditioning treatments with intra-medial septum injection of different doses of histamine (0.5-15 microg/rat) induced a significant CPP for the drug-associated place. Using a 3-day schedule of conditioning, it was found that the histamine H1 receptor antagonist, pyrilamine (10 and 15 microg/rat, intra-medial septum) also induced a significant place preference. In addition, pyrilamine inhibited the histamine (7.5 microg/rat)-induced place preference. Intra-medial septum administration of the histamine H2 receptor antagonist, ranitidine (5-15 microg/rat) alone or in combination with histamine did not produce a significant place preference or place aversion. On the other hand, intra-medial septum administration of the dopamine D1 receptor antagonist, SCH 233390 (0.5, 0.75 and 1 microg/rat) inhibited the histamine (7.5 microg/rat) or pyrilamine (15 microg/rat)-induced place preference in a dose-dependent manner, but no effect was observed for the dopamine D2 receptor antagonist, sulpiride on the histamine or pyrilamine response. The administration of histamine (2.5-15 microg/rat) or pyrilamine (10 and 15 microg/rat) during acquisition increased locomotor activity of the animals on the testing days. The results suggest that histaminergic receptors of the medial septum may be involved in CPP and thus it is postulated that dopamine D1 receptors may play an important role in this effect.
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Affiliation(s)
- Mohammad-Reza Zarrindast
- Department of Pharmacology and Iranian National Center for Addiction Studies, School of Medicine, Tehran University of Medical Sciences, PO Box 13145-784, Tehran, Iran.
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21
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D'Intino G, Vaccari F, Sivilia S, Scagliarini A, Gandini G, Giardino L, Calzà L. A molecular study of hippocampus in dogs with convulsion during canine distemper virus encephalitis. Brain Res 2006; 1098:186-95. [PMID: 16765333 DOI: 10.1016/j.brainres.2006.04.051] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2006] [Revised: 04/11/2006] [Accepted: 04/16/2006] [Indexed: 11/24/2022]
Abstract
In this study, we have investigated the expression of the nuclear transcription factor (c-Fos, NFkB), growth factors (nerve growth factor--NGF, brain-derived neurotrophic factor--BDNF), peptides (enkephalin, galanin) and glutamate transporter (AA 504-523 rat EAAC1) in 6 dogs sacrificed immediately after seizure attack during encephalomyelitis due to canine distemper virus (CDV) (as assessed by clinical examination, RT-PCR and viral RNA detection either in blood or brain tissue and CDV immunohistochemistry in brain slices). In all these CDV affected dogs, the observed neurological signs included untreatable seizures, leading to cluster seizure activity and status epilepticus. In the inter-ictal phase abnormal mentation, postural and gait deficits and sometimes involuntary movements such as myoclonus were recorded. The same investigation was carried out in 5 control dogs affected by different disorders, all characterized by the absence of seizures. Brains were dissected out immediately after euthanasia and fixed; sections collected from the dorsal hippocampus were processed for immunohistochemistry. By comparing hippocampus sections obtained from dog with and without seizure, the following regulations were observed. A strong up-regulation of glutamate transporter throughout the cell layers was found together with the onset of nuclear Fos and NFkB-IR in the pyramidal cell layer X. Among the investigated peptides, we observed a slight increase in enkephalinergic fibers and a strong up-regulation of mu-opioid receptors, whereas galanin-IR seemed to be weaker. Finally, both NGF and BDNF expression was strongly up-regulated. BDNF-IR was mainly localized in the apical dendrite in pyramidal neurons. To our knowledge, these data offer the first indication that molecular events described in experimental kindling also occur during spontaneous pathology in animal species sharing close similarities to human neuropathology.
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Affiliation(s)
- Giulia D'Intino
- Department of Veterinary Morphophysiology and Animal Production, DIMORFIPA, University of Bologna, Via Tolara di Sopra 50, 40064 Ozzano Emilia, Bologna, Italy
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22
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Le Merrer J, Cagniard B, Cazala P. Modulation of anxiety by μ-opioid receptors of the lateral septal region in mice. Pharmacol Biochem Behav 2006; 83:465-79. [PMID: 16626794 DOI: 10.1016/j.pbb.2006.03.008] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/17/2005] [Revised: 02/28/2006] [Accepted: 03/03/2006] [Indexed: 11/28/2022]
Abstract
Morphine and opiates are known to exert anxiolytic effects, probably by interacting with the GABAergic system. The lateral septum (LS), mainly constituted of GABA neurons, exhibits high densities of mu-opiate receptors and could thus represent one the brain sites where opiates interact with GABAergic transmission to modulate anxiety. We examined the effects of intra-LS morphine injections on measures of anxiety using the elevated plus-maze and hole-board tests. Fos imaging was used to identify neural circuits involved in anxiety modulation. Unilateral intra-LS morphine (100 or 500 ng/100 nl) decreased open-arm exploration in the plus-maze and reduced head-dipping frequency in the hole-board, an anxiogenic-like effect associated with decreased Fos expression in the ventral LS, the dorsal hippocampus and the anterior hypothalamus. Anatomical specificity was assessed by injecting morphine into the medial septum, which failed to produce anxiogenesis. Pre-injection of the mu-opioid receptor antagonist naloxonazine (100 ng/100 nl) into LS reversed morphine-induced anxiogenesis and the associated pattern of Fos expression, indicating a specific recruitment of mu-opioid receptors by morphine. Surprisingly, bilateral morphine injections (20 to 500 ng/100 nl) were not found anxiogenic, perhaps due to their stimulant effect. Taken together, these results suggest that LS mu-opioid receptors participate to the modulation of anxiety.
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Affiliation(s)
- Julie Le Merrer
- Laboratoire de Neurosciences Cognitives, CNRS UMR 5106, Université Bordeaux I, Avenue des Facultés, 33405 Talence, France.
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23
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Hebb ALO, Poulin JF, Roach SP, Zacharko RM, Drolet G. Cholecystokinin and endogenous opioid peptides: interactive influence on pain, cognition, and emotion. Prog Neuropsychopharmacol Biol Psychiatry 2005; 29:1225-38. [PMID: 16242828 DOI: 10.1016/j.pnpbp.2005.08.008] [Citation(s) in RCA: 98] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 08/26/2005] [Indexed: 11/22/2022]
Abstract
It is well documented that stressful life experiences contribute to the etiology of human mood disorders. Cholecystokinin (CCK) is a neuropeptide found in high concentrations throughout the central nervous system, where it is involved in numerous physiological functions. A role for CCK in the induction and persistence of anxiety and major depression appears to be conspicuous. While increased CCK has been associated with motivational loss, anxiety and panic attacks, an increase in mesocorticolimbic opioid availability has been associated with coping and mood elevation. The close neuroanatomical distribution of CCK with opioid peptides in the limbic system suggests that there may be an opioid-CCK link in the modulation and expression of anxiety or stressor-related behaviors. In effect, while CCK induces relatively protracted behavioral disturbances in both animal and human subjects following stressor applications, opioid receptor activation may change the course of psychopathology. The antagonistic interaction of CCK and opioid peptides is evident in psychological disturbances as well as stress-induced analgesia. There appears to be an intricate balance between the memory-enhancing and anxiety-provoking effects of CCK on one hand, and the amnesic and anxiolytic effects of opioid peptides on the other hand. Potential anxiogenic and mnemonic influences of site-specific mesocorticolimbic CCK and opioid peptide availability, the relative contributions of specific CCK and opioid receptors, as well as the time course underlying neuronal substrates of long-term behavioral disturbances as a result of stressor manipulations, are discussed.
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Affiliation(s)
- Andrea L O Hebb
- Department of Pharmacology, Faculty of Medicine, Dalhousie University, Sir Charles Tupper Medical Building, 5850 College Street, Halifax, NS, Canada B3H 1X5.
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24
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Kaplan TJ, Skyers PR, Tabori NE, Drake CT, Milner TA. Ultrastructural evidence for mu-opioid modulation of cholinergic pathways in rat dentate gyrus. Brain Res 2004; 1019:28-38. [PMID: 15306235 DOI: 10.1016/j.brainres.2004.05.050] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/14/2004] [Indexed: 11/30/2022]
Abstract
Within the rat hippocampal formation, cholinergic afferents and mu-opioid receptors (MORs) are involved in many crucial learning processes, including those associated with drug reward. Pharmacological data, and the overlapping distributions of cholinergic and mu-opioid systems, particularly in the dentate gyrus, suggest that MOR activation is a potential mechanism for endogenous opioid modulation of cholinergic activity. To date, anatomical evidence supporting this has not been reported. To delineate the relationship between cholinergic afferents and MOR-containing processes in the dentate gyrus, hippocampal sections were dually immunolabeled for vesicular acetylcholine transporter (VAChT) and MOR-1 and examined by electron microscopy. VAChT immunoreactivity was in unmyelinated axons and axon terminals, and was most often associated with small synaptic vesicles. MOR immunoreactivity was found in axons, axon terminals and, to a lesser extent, perikarya, which resembled GABAergic basket cells. Semi-quantitative ultrastructural analysis revealed that from 5% to 13% (depending on laminar location) of VAChT-immunoreactive (ir) presynaptic profiles contained MOR immunoreactivity. Additionally, 7% of VAChT-ir presynaptic profiles directly apposed MOR-ir axons and terminals, and there were almost no appositions to MOR-ir dendrites. These data suggest that opioids may directly and indirectly modulate acetylcholine release and/or reuptake. In the hilus and molecular layer, 4% of VAChT-ir terminals contacted dendritic shafts that were also contacted by MOR-ir terminals. This suggests that cholinergic afferents and MOR-containing afferents can converge on granule cell dendrites (which are restricted to the molecular layer) and on interneuron dendrites in the hilus. The results of this study provide ultrastructural evidence for direct and indirect modulation of cholinergic systems by mu-opioids in the hippocampal formation.
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Affiliation(s)
- Theodore J Kaplan
- Division of Neurobiology, Department of Neurology and Neuroscience, Weill Medical College of Cornell University, 411 East 69th Street, New York, NY 10021, USA
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25
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Griffioen KJS, Venkatesan P, Huang ZG, Wang X, Bouairi E, Evans C, Gold A, Mendelowitz D. Fentanyl inhibits GABAergic neurotransmission to cardiac vagal neurons in the nucleus ambiguus. Brain Res 2004; 1007:109-15. [PMID: 15064141 DOI: 10.1016/j.brainres.2004.02.010] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/11/2004] [Indexed: 11/25/2022]
Abstract
Fentanyl citrate is a synthetic opiate analgesic often used clinically for neonatal anesthesia. Although fentanyl significantly depresses heart rate, the mechanism of inducing bradycardia remains unclear. One possible site of action is the cardioinhibitory parasympathetic vagal neurons in the nucleus ambiguus (NA), from which originates control of heart rate and cardiac function. Inhibitory synaptic activity to cardiac vagal neurons is a major determinant of their activity. Therefore, the effect of fentanyl on GABAergic neurotransmission to parasympathetic cardiac vagal neurons was studied using whole-cell patch clamp electrophysiology. Application of fentanyl induced a reduction in both the frequency and amplitude of GABAergic IPSCs in cardiac vagal neurons. This inhibition was mediated at both pre- and postsynaptic sites as evidenced by a dual decrease in the frequency and amplitude of spontaneous miniature IPSCs. Application of the selective micro-antagonist CTOP abolished the fentanyl-mediated inhibition of GABAergic IPSCs. These results demonstrate that fentanyl acts on micro-opioid receptors on cardiac vagal neurons and neurons preceding them to reduce GABAergic neurotransmission and increase parasympathetic activity. The inhibition of GABAergic effects may be one mechanism by which fentanyl induces bradycardia.
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Affiliation(s)
- Kathleen J S Griffioen
- Department of Pharmacology and Physiology, George Washington University, 2300 Eye Street N.W., Washington, DC 20037, USA.
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26
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Parent MB, Baxter MG. Septohippocampal acetylcholine: involved in but not necessary for learning and memory? Learn Mem 2004; 11:9-20. [PMID: 14747512 PMCID: PMC1668717 DOI: 10.1101/lm.69104] [Citation(s) in RCA: 148] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
The neurotransmitter acetylcholine (ACh) has been accorded an important role in supporting learning and memory processes in the hippocampus. Cholinergic activity in the hippocampus is correlated with memory, and restoration of ACh in the hippocampus after disruption of the septohippocampal pathway is sufficient to rescue memory. However, selective ablation of cholinergic septohippocampal projections is largely without effect on hippocampal-dependent learning and memory processes. We consider the evidence underlying each of these statements, and the contradictions they pose for understanding the functional role of hippocampal ACh in memory. We suggest that although hippocampal ACh is involved in memory in the intact brain, it is not necessary for many aspects of hippocampal memory function.
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Affiliation(s)
- Marise B Parent
- Department of Psychology and Center for Behavioral Neuroscience, Georgia State University, Atlanta, Georgia 30303, USA.
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27
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Sullivan SD, Moenter SM. Gamma-aminobutyric acid neurons integrate and rapidly transmit permissive and inhibitory metabolic cues to gonadotropin-releasing hormone neurons. Endocrinology 2004; 145:1194-202. [PMID: 14645118 DOI: 10.1210/en.2003-1374] [Citation(s) in RCA: 77] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Negative energy balance inhibits fertility by decreasing GnRH release; however, the mechanisms are not well understood. GnRH neurons can be excited by activation of gamma-aminobutyric acid (GABA)(A) receptors, and GABAergic neurons provide a major synaptic input. We hypothesized that permissive metabolic signals mediated by leptin and inhibitory signals conveyed by neuropeptide Y (NPY) and opiates rapidly alter GABA(A) receptor-mediated drive to GnRH neurons. In fed and fasted female mice, GABAergic postsynaptic currents (PSCs) were recorded from GnRH neurons before and after in vitro treatment with leptin, NPY, or met-enkephalin. Leptin increased PSC frequency in fed and fasted mice, indicating that it increased presynaptic activity. Leptin also increased PSC size. Inhibiting leptin receptor signaling pathways within GnRH neurons abolished the latter effect, indicating a direct action on these cells. In fed, but not fasted, mice, NPY and met-enkephalin decreased PSC frequency in an antagonist-reversible manner, but did not alter PSC size. NPY-1 receptor antagonists alone increased frequency in fed and fasted mice, as did opiate receptor blockade in fasted animals, suggesting that endogenous NPY and opiates modulate GABAergic drive to GnRH neurons. These data suggest that GABAergic afferents integrate metabolic signals for delivery to GnRH neurons. Decreased sensitivity to NPY and opiates in fasted mice indicate that these peptides send physiologically relevant signals regarding energy balance to GnRH neurons.
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Affiliation(s)
- Shannon D Sullivan
- Department of Internal Medicine and Cell Biology, University of Virginia, Charlottesville, Virginia 22908, USA
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Härtig W, Bauer A, Brauer K, Grosche J, Hortobágyi T, Penke B, Schliebs R, Harkany T. Functional recovery of cholinergic basal forebrain neurons under disease conditions: old problems, new solutions? Rev Neurosci 2003; 13:95-165. [PMID: 12160262 DOI: 10.1515/revneuro.2002.13.2.95] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Recognition of the involvement of cholinergic neurons in the modulation of cognitive functions and their severe dysfunction in neurodegenerative disorders, such as Alzheimer's disease, initiated immense research efforts aimed at unveiling the anatomical organization and cellular characteristics of the basal forebrain (BFB) cholinergic system. Concomitant with our unfolding knowledge about the structural and functional complexity of the BFB cholinergic projection system, multiple pharmacological strategies were introduced to rescue cholinergic nerve cells from noxious attacks; however, a therapeutic breakthrough is still awaited. In this review, we collected recent findings that significantly contributed to our better understanding of cholinergic functions under disease conditions, and to the design of effective means to restore lost or damaged cholinergic functions. To this end, we first provide a brief survey of the neuroanatomical organization of BFB nuclei with emphasis on major evolutionary differences among mammalian species, in particular rodents and primates, and discuss limitations of the translation of experimental data to human therapeutic applications. Subsequently, we summarize the involvement of cholinergic dysfunction in the pathogenesis of severe neurological conditions, including stroke, traumatic brain injury, virus encephalitis and Alzheimer's disease, and emphasize the critical role of pro-inflammatory cytokines as common mediators of cholinergic neuronal damage. Moreover, we review leading functional concepts on the limited recovery of cholinergic neurons and their impaired plastic re-modeling, as well as on the hampered interplay of the ascending cholinergic and monoaminergic projection systems under neurodegenerative conditions. In addition, recent advances in the dynamic labeling of living cholinergic neurons by fluorochromated antibodies, referred to as in vivo labeling, and novel neuroimaging approaches as potential diagnostic tools of progressive cholinergic decline are surveyed. Finally, the potential of cell replacement strategies using embryonic and adult stem cells, and multipotent neural progenitors, as a means to recover damaged cholinergic functions, is discussed.
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Affiliation(s)
- Wolfgang Härtig
- Department of Neurochemistry, Paul Flechsig Institute for Brain Research, University of Leipzig, Germany
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Skyers PS, Einheber S, Pierce JP, Milner TA. Increased mu-opioid receptor labeling is found on inner molecular layer terminals of the dentate gyrus following seizures. Exp Neurol 2003; 179:200-9. [PMID: 12618127 DOI: 10.1016/s0014-4886(02)00018-3] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
The hippocampal formation is a brain region sensitive to seizure development, a phenomenon thought to be mediated in part by mu-opioid receptor (MOR) activation. Previous studies have found a delayed increase in MOR immunoreactivity (IR) in the inner molecular layer (IML) of the dentate gyrus after experimentally induced seizures. However, whether these increases in MOR-IR are restricted to certain cell types or cellular compartments (i.e., presynaptic, postsynaptic, or glial profiles) has not been determined. Thus, the present study examined which subcellular profiles demonstrate changes in MOR-IR after kainic acid (KA)-induced seizures. Light microscopic (LM) analysis demonstrated seizure-induced increases in MOR-IR at three points of the IML (dorsal blade, ventral blade, and crest) at three levels of section (septal, mid-septotemporal, and temporal). Electron microscopic analysis of the IML revealed that MOR-IR was present in the same types of cellular profiles in both control and KA-treated rats. However, a significant increase in the number of MOR-labeled terminal profiles was revealed in KA-treated rats compared to controls. Additionally, some MOR-labeled terminals in KA-treated rats possessed excitatory-type morphology and contained enkephalin or dynorphin, peptides found in mossy fiber terminals. These data suggest that most of the seizure-induced increases in MOR expression in the IML are associated with terminals originating from several different neuronal populations, including granule cells, and possibly, surviving GABAergic interneurons, septal cholinergic, and/or supramamillary projection neurons.
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Affiliation(s)
- P S Skyers
- Division of Neurobiology, Department of Neurology and Neuroscience, Weill Medical College of Cornell University, New York, NY 10021, USA
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Venkatesan P, Wang J, Evans C, Irnaten M, Mendelowitz D. Endomorphin-2 inhibits GABAergic inputs to cardiac parasympathetic neurons in the nucleus ambiguus. Neuroscience 2002; 113:975-83. [PMID: 12182901 DOI: 10.1016/s0306-4522(02)00244-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The nucleus ambiguus is an area containing cardiac vagal neurons, from which originates most of the parasympathetic control regulating heart rate and cardiac function. GABAergic pathways to these neurons have recently been described, yet modulation of this GABAergic input and its impact upon cardiac vagal neurons is unknown. The nucleus ambiguus has been shown to contain mu-opioid receptors and endomorphin-1 and endomorphin-2, the endogenous peptide ligands for the mu-receptor, whilst microinjections of opioids in the ambiguus area evoke bradycardia. The present study therefore examined the effects of endomorphin-1, endomorphin-2 and DAMGO (a synthetic, mu-selective agonist) on spontaneous GABAergic IPSCs in cardiac parasympathetic neurons. Only endomorphin-2 (100 microM) produced a significant inhibition, of both the frequency (-22.8%) and the amplitude (-30.5%) of the spontaneous IPSCs in cardiac vagal neurons. The inhibitory effects of endomorphin-2 were blocked by naloxonazine (10 microM), a selective mu(1) receptor antagonist. Naloxonazine alone (10 microM) had a potentiating effect on the frequency of the GABAergic IPSCs (+161.43%) but not on the amplitude, indicating that GABA release to cardiac vagal neurons may be under tonic control of opioids acting at the mu(1) receptor. Endomorphin-2 did not reduce the responses evoked by exogenous application of GABA. These results indicate that endomorphin-2 acts on mu(1) receptors located on precedent neurons to decrease GABAergic input to cardiac vagal neurons located in the nucleus ambiguus. The subsequent increase in parasympathetic outflow to the heart may be one mechanism by which mu-selective opioids act to induce bradycardia.
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Affiliation(s)
- P Venkatesan
- Department of Pharmacology, George Washington University, 2300 Eye Street NW, Washington, DC 20037, USA
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31
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Drake CT, Milner TA. Mu opioid receptors are in discrete hippocampal interneuron subpopulations. Hippocampus 2002; 12:119-36. [PMID: 12000113 DOI: 10.1002/hipo.1107] [Citation(s) in RCA: 113] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
In the rat hippocampal formation, application of mu opioid receptor (MOR) agonists disinhibits principal cells, promoting excitation-dependent processes such as epileptogenesis and long-term potentiation. However, the precise location of MORs in particular inhibitory circuits, has not been determined, and the roles of MORs in endogenous functioning are unclear. To address these issues, the distribution of MOR-like immunoreactivity (-li) was examined in several populations of inhibitory hippocampal neurons in the CA1 region using light and electron microscopy. We found that MOR-li was present in many parvalbumin-containing basket cells, but absent from cholecystokinin-labeled basket cells. MOR-li was also commonly in interneurons containing somatostatin-li or neuropeptide Y-li that resembled the "oriens-lacunosum-moleculare" (O-LM) interneurons innervating pyramidal cell distal dendrites. Finally, MOR-li was in some vasoactive intestinal peptide- or calretinin-containing profiles resembling interneurons that primarily innervate other interneurons. These findings indicate that MOR-containing neurons form a neurochemically and functionally heterogeneous subset of hippocampal GABAergic neurons. MORs are most frequently on interneurons that are specialized to inhibit pyramidal cells, and are on a limited number of interneurons that target other interneurons. Moreover, the distribution of MORs to different neuronal types in several laminae, some relatively far from endogenous opioids, suggests normal functional roles that are different from the actions seen with exogenous agonists such as morphine.
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Affiliation(s)
- Carrie T Drake
- Department of Neurology and Neuroscience, Weill Medical College of Cornell University, New York, New York 10021, USA.
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Abstract
This paper is the twenty-third installment of the annual review of research concerning the opiate system. It summarizes papers published during 2000 that studied the behavioral effects of the opiate peptides and antagonists, excluding the purely analgesic effects, although stress-induced analgesia is included. The specific topics covered this year include stress; tolerance and dependence; learning, memory, and reward; eating and drinking; alcohol and other drugs of abuse; sexual activity, pregnancy, and development; mental illness and mood; seizures and other neurological disorders; electrical-related activity; general activity and locomotion; gastrointestinal, renal, and hepatic function; cardiovascular responses; respiration and thermoregulation; and immunological responses.
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Affiliation(s)
- A L Vaccarino
- Department of Psychology, University of New Orleans, New Orleans, LA 70148, USA.
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33
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Gärtner U, Härtig W, Brauer K, Brückner G, Arendt T. Electron microscopic evidence for different myelination of rat septohippocampal fibres. Neuroreport 2001; 12:17-20. [PMID: 11201081 DOI: 10.1097/00001756-200101220-00011] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Rat septohippocampal fibres are known to originate from GABAergic parvalbumin-containing, fast-firing, fast-conducting neurons and from cholinergic slow-firing, slow-conducting neurons. In the present electron microscopic study, based on immunocytochemical demonstration of parvalbumin and choline acetyltransferase in transverse and horizontal septal sections, it was shown that parvalbumin-immunoreactive fibres are myelinated, but the vast majority of cholinergic fibres are not. As revealed, especially in horizontal sections, the cholinergic axons show considerably finer calibres than parvalbumin-containing ones. These results confirm and extend our previous light microscopic findings. It can be concluded that differences in conduction velocities, presence or absence of myelin sheaths and differences axonal diameters are correlated in the septohippocampal pathway.
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Affiliation(s)
- U Gärtner
- Department of Neuroanatomy, Paul Flechsig Institute for Brain Research, University of Leipzig, Germany
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Alreja M, Wu M, Liu W, Atkins JB, Leranth C, Shanabrough M. Muscarinic tone sustains impulse flow in the septohippocampal GABA but not cholinergic pathway: implications for learning and memory. J Neurosci 2000; 20:8103-10. [PMID: 11050132 PMCID: PMC6772717] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/18/2023] Open
Abstract
Systemic infusions of the muscarinic cholinergic receptor antagonists atropine and scopolamine (atr/scop) produce an amnesic syndrome in humans, subhuman primates, and rodents. In humans, this syndrome may resemble early symptoms of Alzheimer's disease. Behavioral studies in rats have demonstrated that the medial septum/diagonal band of Broca (MSDB), which sends cholinergic and GABAergic projections to the hippocampus, is a critical locus in mediating the amnesic effects of atr/scop. The amnesic effects of atr/scop in the MSDB have been presumed but not proven to be caused by a decrease in hippocampal acetylcholine (ACh) release after blockade of a muscarinic tone in the MSDB. Using electrophysiological recordings and fluorescent-labeling techniques to identify living septohippocampal neurons in rat brain slices, we now report that, contrary to current belief, a blockade of the muscarinic tone in the MSDB does not decrease impulse flow in the septohippocampal cholinergic pathway; instead, it decreases impulse flow in the septohippocampal GABAergic pathway via M(3) muscarinic receptors. We also report that the muscarinic tone in the MSDB is maintained by ACh that is released locally, presumably via axon collaterals of septohippocampal cholinergic neurons. As such, cognitive deficits that occur in various neurodegenerative disorders that are associated with a loss or atrophy of septohippocampal cholinergic neurons cannot be attributed solely to a decrease in hippocampal acetylcholine release. An additional, possibly more important mechanism may be the concomitant decrease in septohippocampal GABA release and a subsequent disruption in disinhibitory mechanisms in the hippocampus. Restoration of impulse flow in the septohippocampal GABA pathway, possibly via M(3) receptor agonists, may, therefore, be critical for successful treatment of cognitive deficits associated with neurodegenerative disorders such as Alzheimer's and Parkinson's disease.
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Affiliation(s)
- M Alreja
- Departments of Psychiatry, Neurobiology, and Obstetrics and Gynecology, Yale University School of Medicine New Haven, Connecticut 06508, USA.
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Brauer K, Härtig W, Gärtner U, Brückner G, Arendt T. Different myelination of rat septohippocampal fibres as revealed by immunofluorescence double-labelling. Brain Res 2000; 878:188-93. [PMID: 10996150 DOI: 10.1016/s0006-8993(00)02653-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The present study focuses on the myelination of rat septohippocampal fibres that are known to originate from GABAergic parvalbumin-containing, fast-firing, fast-conducting neurons and from cholinergic slow-firing, slow-conducting neurons. With the combined immunofluorescence for parvalbumin/myelin basic protein and choline acetyltransferase/myelin basic protein it was shown that the vast majority of parvalbumin-containing fibres are myelinated, but the choline acetyltransferase-containing fibres are not. Accordingly, our results confirm the expectation that conduction velocities and presence or absence of myelin sheaths are also correlated in the septohippocampal pathway.
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Affiliation(s)
- K Brauer
- Department of Neuroanatomy, Paul Flechsig Institute for Brain Research, University of Leipzig, D-04109 Leipzig, Germany.
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36
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Wu M, Shanabrough M, Leranth C, Alreja M. Cholinergic excitation of septohippocampal GABA but not cholinergic neurons: implications for learning and memory. J Neurosci 2000; 20:3900-8. [PMID: 10804229 PMCID: PMC6772671] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/16/2023] Open
Abstract
The medial septum/diagonal band (MSDB), which gives rise to the septohippocampal pathway, is a critical locus for the mnemonic effects of muscarinic drugs. Infusion of muscarinic cholinergic agonists into the MSDB enhance learning and memory processes both in young and aged rats and produce a continuous theta rhythm in the hippocampus. Intraseptal muscarinic agonists also alleviate the amnesic syndrome produced by systemic administration of muscarinic receptor antagonists. It has been presumed, but not proven, that the cellular mechanisms underlying the effects of muscarinic agonists in the MSDB involve an excitation of septohippocampal cholinergic neurons and a subsequent increase in acetylcholine (ACh) release in the hippocampus. Using a novel fluorescent labeling technique to selectively visualize live septohippocampal cholinergic neurons in rat brain slices, we have found that muscarinic agonists do not excite septohippocampal cholinergic neurons, instead they inhibit a subpopulation of cholinergic neurons. In contrast, unlabeled neurons, confirmed to be noncholinergic, septohippocampal GABA-type neurons using retrograde marking and double-labeling techniques, are profoundly excited by muscarine. Thus, the cognition-enhancing effects of muscarinic drugs in the MSDB cannot be attributed to an increase in hippocampal ACh release. Instead, disinhibitory mechanisms, caused by increased impulse flow in the septohippocampal GABAergic pathway, may underlie the cognition-enhancing effects of muscarinic agonists.
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Affiliation(s)
- M Wu
- Departments of Psychiatry, Obstetrics and Gynecology, and Neurobiology, Yale University School of Medicine and the Ribicoff Research Facilities, Connecticut Mental Health Center, New Haven, Connecticut 06508, USA
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