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Chung L, Jing M, Li Y, Tapper AR. Feed-forward Activation of Habenula Cholinergic Neurons by Local Acetylcholine. Neuroscience 2023; 529:172-182. [PMID: 37572877 PMCID: PMC10840387 DOI: 10.1016/j.neuroscience.2023.07.030] [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: 01/31/2023] [Revised: 07/10/2023] [Accepted: 07/27/2023] [Indexed: 08/14/2023]
Abstract
While the functional and behavioral role of the medial habenula (MHb) is still emerging, recent data indicate an involvement of this nuclei in regulating mood, aversion, and addiction. Unique to the MHb is a large cluster of cholinergic neurons that project to the interpeduncular nucleus and densely express acetylcholine receptors (AChRs) suggesting that the activity of these cholinergic neurons may be regulated by ACh itself. Whether endogenous ACh from within the habenula regulates cholinergic neuron activity has not been demonstrated. Supporting a role for ACh in modulating MHb activity, acetylcholinesterase inhibitors increased the firing rate of MHb cholinergic neurons in mouse habenula slices, an effect blocked by AChR antagonists and mediated by ACh which was detected via expressing fluorescent ACh sensors in MHb in vivo. To test if cholinergic afferents innervate MHb cholinergic neurons, we used anterograde and retrograde viral tracing to identify cholinergic inputs. Surprisingly, tracing experiments failed to detect cholinergic inputs into the MHb, including from the septum, suggesting that MHb cholinergic neurons may release ACh within the MHb to drive cholinergic activity. To test this hypothesis, we expressed channelrhodopsin in a portion of MHb cholinergic neurons while recording from non-opsin-expressing neurons. Light pulses progressively increased activity of MHb cholinergic neurons indicating feed-forward activation driven by MHb ACh release. These data indicate MHb cholinergic neurons may utilize a unique feed-forward mechanism to synchronize and increase activity by releasing local ACh.
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Affiliation(s)
- Leeyup Chung
- Brudnick Neuropsychiatric Research Institute, Dept. of Neurobiology, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Miao Jing
- State Key Laboratory of Membrane Biology, Peking University School of Life Sciences, PKU-IDG/McGovern Institute for Brain Research, 100871 Beijing, China; Chinese Institute for Brain Research, 102206 Beijing, China
| | - Yulong Li
- State Key Laboratory of Membrane Biology, Peking University School of Life Sciences, PKU-IDG/McGovern Institute for Brain Research, 100871 Beijing, China; Chinese Institute for Brain Research, 102206 Beijing, China
| | - Andrew R Tapper
- Brudnick Neuropsychiatric Research Institute, Dept. of Neurobiology, University of Massachusetts Medical School, Worcester, MA 01605, USA.
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Nakamura R, Yamazaki T, Kondo Y, Tsukada M, Miyamoto Y, Arakawa N, Sumida Y, Kiya T, Arai S, Ohmiya H. Radical Caging Strategy for Cholinergic Optopharmacology. J Am Chem Soc 2023; 145:10651-10658. [PMID: 37141169 DOI: 10.1021/jacs.3c00801] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Photo-caged methodologies have been indispensable for elucidating the functional mechanisms of pharmacologically active molecules at the cellular level. A photo-triggered removable unit enables control of the photo-induced expression of pharmacologically active molecular function, resulting in a rapid increase in the concentration of the bioactive compound near the target cell. However, caging the target bioactive compound generally requires specific heteroatom-based functional groups, limiting the types of molecular structures that can be caged. We have developed an unprecedented methodology for caging/uncaging on carbon atoms using a unit with a photo-cleavable carbon-boron bond. The caging/uncaging process requires installation of the CH2-B group on the nitrogen atom that formally assembles an N-methyl group protected with a photoremovable unit. N-Methylation proceeds by photoirradiation via carbon-centered radical generation. Using this radical caging strategy to cage previously uncageable bioactive molecules, we have photocaged molecules with no general labeling sites, including acetylcholine, an endogenous neurotransmitter. Caged acetylcholine provides an unconventional tool for optopharmacology to clarify neuronal mechanisms on the basis of photo-regulating acetylcholine localization. We demonstrated the utility of this probe by monitoring uncaging in HEK cells expressing a biosensor to detect ACh on the cell surface, as well as Ca2+ imaging in Drosophila brain cells (ex vivo).
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Affiliation(s)
- Rikako Nakamura
- Institute for Chemical Research, Kyoto University, Gokasho, Uji, Kyoto 611-0011, Japan
| | - Takeru Yamazaki
- WPI Nano Life Science Institute (NanoLSI), Kanazawa University, Kanazawa 920-1164, Japan
| | - Yui Kondo
- Division of Pharmaceutical Sciences, Graduate School of Medical Sciences, Kanazawa University, Kakuma-machi, Kanazawa 920-1192, Japan
| | - Miho Tsukada
- Division of Pharmaceutical Sciences, Graduate School of Medical Sciences, Kanazawa University, Kakuma-machi, Kanazawa 920-1192, Japan
| | - Yusuke Miyamoto
- Institute for Chemical Research, Kyoto University, Gokasho, Uji, Kyoto 611-0011, Japan
| | - Nozomi Arakawa
- Division of Pharmaceutical Sciences, Graduate School of Medical Sciences, Kanazawa University, Kakuma-machi, Kanazawa 920-1192, Japan
| | - Yuto Sumida
- Division of Pharmaceutical Sciences, Graduate School of Medical Sciences, Kanazawa University, Kakuma-machi, Kanazawa 920-1192, Japan
| | - Taketoshi Kiya
- Division of Life Sciences, Graduate School of Natural Science and Technology, Kanazawa University, Kakuma-machi, Kanazawa 920-1192, Japan
| | - Satoshi Arai
- WPI Nano Life Science Institute (NanoLSI), Kanazawa University, Kanazawa 920-1164, Japan
| | - Hirohisa Ohmiya
- Institute for Chemical Research, Kyoto University, Gokasho, Uji, Kyoto 611-0011, Japan
- JST, PRESTO, 4-1-8 Honcho, Kawaguchi, Saitama 332-0012, Japan
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Wills L, Ables JL, Braunscheidel KM, Caligiuri SPB, Elayouby KS, Fillinger C, Ishikawa M, Moen JK, Kenny PJ. Neurobiological Mechanisms of Nicotine Reward and Aversion. Pharmacol Rev 2022; 74:271-310. [PMID: 35017179 PMCID: PMC11060337 DOI: 10.1124/pharmrev.121.000299] [Citation(s) in RCA: 33] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2021] [Accepted: 08/24/2021] [Indexed: 12/27/2022] Open
Abstract
Neuronal nicotinic acetylcholine receptors (nAChRs) regulate the rewarding actions of nicotine contained in tobacco that establish and maintain the smoking habit. nAChRs also regulate the aversive properties of nicotine, sensitivity to which decreases tobacco use and protects against tobacco use disorder. These opposing behavioral actions of nicotine reflect nAChR expression in brain reward and aversion circuits. nAChRs containing α4 and β2 subunits are responsible for the high-affinity nicotine binding sites in the brain and are densely expressed by reward-relevant neurons, most notably dopaminergic, GABAergic, and glutamatergic neurons in the ventral tegmental area. High-affinity nAChRs can incorporate additional subunits, including β3, α6, or α5 subunits, with the resulting nAChR subtypes playing discrete and dissociable roles in the stimulatory actions of nicotine on brain dopamine transmission. nAChRs in brain dopamine circuits also participate in aversive reactions to nicotine and the negative affective state experienced during nicotine withdrawal. nAChRs containing α3 and β4 subunits are responsible for the low-affinity nicotine binding sites in the brain and are enriched in brain sites involved in aversion, including the medial habenula, interpeduncular nucleus, and nucleus of the solitary tract, brain sites in which α5 nAChR subunits are also expressed. These aversion-related brain sites regulate nicotine avoidance behaviors, and genetic variation that modifies the function of nAChRs in these sites increases vulnerability to tobacco dependence and smoking-related diseases. Here, we review the molecular, cellular, and circuit-level mechanisms through which nicotine elicits reward and aversion and the adaptations in these processes that drive the development of nicotine dependence. SIGNIFICANCE STATEMENT: Tobacco use disorder in the form of habitual cigarette smoking or regular use of other tobacco-related products is a major cause of death and disease worldwide. This article reviews the actions of nicotine in the brain that contribute to tobacco use disorder.
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Affiliation(s)
- Lauren Wills
- Nash Family Department of Neuroscience, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, New York, New York
| | - Jessica L Ables
- Nash Family Department of Neuroscience, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, New York, New York
| | - Kevin M Braunscheidel
- Nash Family Department of Neuroscience, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, New York, New York
| | - Stephanie P B Caligiuri
- Nash Family Department of Neuroscience, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, New York, New York
| | - Karim S Elayouby
- Nash Family Department of Neuroscience, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, New York, New York
| | - Clementine Fillinger
- Nash Family Department of Neuroscience, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, New York, New York
| | - Masago Ishikawa
- Nash Family Department of Neuroscience, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, New York, New York
| | - Janna K Moen
- Nash Family Department of Neuroscience, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, New York, New York
| | - Paul J Kenny
- Nash Family Department of Neuroscience, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, New York, New York
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Maltan L, Najjar H, Tiffner A, Derler I. Deciphering Molecular Mechanisms and Intervening in Physiological and Pathophysiological Processes of Ca 2+ Signaling Mechanisms Using Optogenetic Tools. Cells 2021; 10:3340. [PMID: 34943850 PMCID: PMC8699489 DOI: 10.3390/cells10123340] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2021] [Revised: 11/17/2021] [Accepted: 11/22/2021] [Indexed: 11/16/2022] Open
Abstract
Calcium ion channels are involved in numerous biological functions such as lymphocyte activation, muscle contraction, neurotransmission, excitation, hormone secretion, gene expression, cell migration, memory, and aging. Therefore, their dysfunction can lead to a wide range of cellular abnormalities and, subsequently, to diseases. To date various conventional techniques have provided valuable insights into the roles of Ca2+ signaling. However, their limited spatiotemporal resolution and lack of reversibility pose significant obstacles in the detailed understanding of the structure-function relationship of ion channels. These drawbacks could be partially overcome by the use of optogenetics, which allows for the remote and well-defined manipulation of Ca2+-signaling. Here, we review the various optogenetic tools that have been used to achieve precise control over different Ca2+-permeable ion channels and receptors and associated downstream signaling cascades. We highlight the achievements of optogenetics as well as the still-open questions regarding the resolution of ion channel working mechanisms. In addition, we summarize the successes of optogenetics in manipulating many Ca2+-dependent biological processes both in vitro and in vivo. In summary, optogenetics has significantly advanced our understanding of Ca2+ signaling proteins and the used tools provide an essential basis for potential future therapeutic application.
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Affiliation(s)
| | | | | | - Isabella Derler
- Institute of Biophysics, JKU Life Science Center, Johannes Kepler University Linz, A-4020 Linz, Austria; (L.M.); (H.N.); (A.T.)
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Wills L, Kenny PJ. Addiction-related neuroadaptations following chronic nicotine exposure. J Neurochem 2021; 157:1652-1673. [PMID: 33742685 DOI: 10.1111/jnc.15356] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2021] [Revised: 03/14/2021] [Accepted: 03/15/2021] [Indexed: 12/16/2022]
Abstract
The addiction-relevant molecular, cellular, and behavioral actions of nicotine are derived from its stimulatory effects on neuronal nicotinic acetylcholine receptors (nAChRs) in the central nervous system. nAChRs expressed by dopamine-containing neurons in the ventral midbrain, most notably in the ventral tegmental area (VTA), contribute to the reward-enhancing properties of nicotine that motivate the use of tobacco products. nAChRs are also expressed by neurons in brain circuits that regulate aversion. In particular, nAChRs expressed by neurons in the medial habenula (mHb) and the interpeduncular nucleus (IPn) to which the mHb almost exclusively projects regulate the "set-point" for nicotine aversion and control nicotine intake. Different nAChR subtypes are expressed in brain reward and aversion circuits and nicotine intake is titrated to maximally engage reward-enhancing nAChRs while minimizing the recruitment of aversion-promoting nAChRs. With repeated exposure to nicotine, reward- and aversion-related nAChRs and the brain circuits in which they are expressed undergo adaptations that influence whether tobacco use will transition from occasional to habitual. Genetic variation that influences the sensitivity of addiction-relevant brain circuits to the actions of nicotine also influence the propensity to develop habitual tobacco use. Here, we review some of the key advances in our understanding of the mechanisms by which nicotine acts on brain reward and aversion circuits and the adaptations that occur in these circuits that may drive addiction to nicotine-containing tobacco products.
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Affiliation(s)
- Lauren Wills
- Nash Family Department of Neuroscience, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, New York, NY, USA
| | - Paul J Kenny
- Nash Family Department of Neuroscience, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, New York, NY, USA
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Thapaliya ER, Mony L, Sanchez R, Serraz B, Paoletti P, Ellis-Davies GCR. Photochemical control of drug efficacy - a comparison of uncaging and photoswitching ifenprodil on NMDA receptors. CHEMPHOTOCHEM 2021; 5:445-454. [PMID: 36540756 PMCID: PMC9762817 DOI: 10.1002/cptc.202000240] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Indexed: 09/29/2023]
Abstract
Ifenprodil is an important negative allosteric modulator of the N-methyl-D-aspartate (NMDA) receptors. We have synthesized caged and photoswitchable derivatives of this small molecule drug. Caged ifenprodil was biologically inert before photolysis, UV irradiation efficiently released the drug allowing selective inhibition of GluN2B-containing NMDA receptors. Azobenzene-modified ifenprodil, on the other hand, is inert in both its trans and cis configurations, although in silico modeling predicted the trans form to be able to bind to the receptor. The disparity in effectiveness between the two compounds reflects, in part, the inherent ability of each method in manipulating the binding properties of drugs. With appropriate structure-activity relationship uncaging enables binary control of effector binding, whereas photoswitching using feely diffusable chromophores shifts the dose-response curve of drug-receptor interaction. Our data suggest that the efficacy of pharmacophores having a confined binding site such as ifenprodil can be controlled more easily by uncaging in comparison to photoswitching.
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Affiliation(s)
- Ek Raj Thapaliya
- Department of Neuroscience, Mount Sinai School of Medicine, New York, NY 10029, USA
- Equal contribution
| | - Laetitia Mony
- Institut de Biologie de l’Ecole Normale Supérieure (IBENS), École Normale Supérieure, CNRS, INSERM, Université PSL, Paris 75005, France
- Equal contribution
| | - Roberto Sanchez
- Department of Pharmacological Sciences and Drug Discovery Institute, Mount Sinai School of Medicine, New York, NY 10029, USA
| | - Benjamin Serraz
- Institut de Biologie de l’Ecole Normale Supérieure (IBENS), École Normale Supérieure, CNRS, INSERM, Université PSL, Paris 75005, France
| | - Pierre Paoletti
- Institut de Biologie de l’Ecole Normale Supérieure (IBENS), École Normale Supérieure, CNRS, INSERM, Université PSL, Paris 75005, France
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7
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Rapp TL, DeForest CA. Targeting drug delivery with light: A highly focused approach. Adv Drug Deliv Rev 2021; 171:94-107. [PMID: 33486009 PMCID: PMC8127392 DOI: 10.1016/j.addr.2021.01.009] [Citation(s) in RCA: 64] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Revised: 01/04/2021] [Accepted: 01/08/2021] [Indexed: 12/23/2022]
Abstract
Light is a uniquely powerful tool for controlling molecular events in biology. No other external input (e.g., heat, ultrasound, magnetic field) can be so tightly focused or so highly regulated as a clinical laser. Drug delivery vehicles that can be photonically activated have been developed across many platforms, from the simplest "caging" of therapeutics in a prodrug form, to more complex micelles and circulating liposomes that improve drug uptake and efficacy, to large-scale hydrogel platforms that can be used to protect and deliver macromolecular agents including full-length proteins. In this Review, we discuss recent innovations in photosensitive drug delivery and highlight future opportunities to engineer and exploit such light-responsive technologies in the clinical setting.
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Affiliation(s)
- Teresa L Rapp
- Department of Chemical Engineering, University of Washington, Seattle, WA 98105, USA
| | - Cole A DeForest
- Department of Chemical Engineering, University of Washington, Seattle, WA 98105, USA; Department of Bioengineering, University of Washington, Seattle, WA 98105, USA; Department of Chemistry, University of Washington, Seattle, WA 98105, USA; Institute of Stem Cell & Regenerative Medicine, University of Washington, Seattle, WA 98109, USA; Molecular Engineering & Sciences Institute, University of Washington, Seattle, WA 98105, USA.
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Paoletti P, Ellis-Davies GCR, Mourot A. Optical control of neuronal ion channels and receptors. Nat Rev Neurosci 2020; 20:514-532. [PMID: 31289380 DOI: 10.1038/s41583-019-0197-2] [Citation(s) in RCA: 117] [Impact Index Per Article: 29.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Light-controllable tools provide powerful means to manipulate and interrogate brain function with relatively low invasiveness and high spatiotemporal precision. Although optogenetic approaches permit neuronal excitation or inhibition at the network level, other technologies, such as optopharmacology (also known as photopharmacology) have emerged that provide molecular-level control by endowing light sensitivity to endogenous biomolecules. In this Review, we discuss the challenges and opportunities of photocontrolling native neuronal signalling pathways, focusing on ion channels and neurotransmitter receptors. We describe existing strategies for rendering receptors and channels light sensitive and provide an overview of the neuroscientific insights gained from such approaches. At the crossroads of chemistry, protein engineering and neuroscience, optopharmacology offers great potential for understanding the molecular basis of brain function and behaviour, with promises for future therapeutics.
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Affiliation(s)
- Pierre Paoletti
- Institut de Biologie de l'Ecole Normale Supérieure (IBENS), Ecole Normale Supérieure, CNRS, INSERM, Université PSL, Paris, France.
| | | | - Alexandre Mourot
- Neuroscience Paris Seine-Institut de Biologie Paris Seine (NPS-IBPS), CNRS, INSERM, Sorbonne Université, Paris, France.
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9
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The habenular G-protein-coupled receptor 151 regulates synaptic plasticity and nicotine intake. Proc Natl Acad Sci U S A 2020; 117:5502-5509. [PMID: 32098843 DOI: 10.1073/pnas.1916132117] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
The habenula, an ancient small brain area in the epithalamus, densely expresses nicotinic acetylcholine receptors and is critical for nicotine intake and aversion. As such, identification of strategies to manipulate habenular activity may yield approaches to treat nicotine addiction. Here we show that GPR151, an orphan G-protein-coupled receptor (GPCR) highly enriched in the habenula of humans and rodents, is expressed at presynaptic membranes and synaptic vesicles and associates with synaptic components controlling vesicle release and ion transport. Deletion of Gpr151 inhibits evoked neurotransmission but enhances spontaneous miniature synaptic currents and eliminates short-term plasticity induced by nicotine. We find that GPR151 couples to the G-alpha inhibitory protein Gαo1 to reduce cyclic adenosine monophosphate (cAMP) levels in mice and in GPR151-expressing cell lines that are amenable to ligand screens. Gpr151- knockout (KO) mice show diminished behavioral responses to nicotine and self-administer greater quantities of the drug, phenotypes rescued by viral reexpression of Gpr151 in the habenula. These data identify GPR151 as a critical modulator of habenular function that controls nicotine addiction vulnerability.
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Sitkowska K, Hoes MF, Lerch MM, Lameijer LN, van der Meer P, Szymański W, Feringa BL. Red-light-sensitive BODIPY photoprotecting groups for amines and their biological application in controlling heart rhythm. Chem Commun (Camb) 2020; 56:5480-5483. [DOI: 10.1039/d0cc02178d] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Protection of amine functionality with a BODIPY-derived photocleavable protecting group enables the control of heart beat frequency with red light.
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Affiliation(s)
- Kaja Sitkowska
- Centre for Systems Chemistry
- Stratingh Institute for Chemistry
- University of Groningen
- Groningen
- The Netherlands
| | - Martijn F. Hoes
- Department of Cardiology
- University of Groningen
- University Medical Centre Groningen
- 9713 GZ Groningen
- The Netherlands
| | - Michael M. Lerch
- Centre for Systems Chemistry
- Stratingh Institute for Chemistry
- University of Groningen
- Groningen
- The Netherlands
| | - Lucien N. Lameijer
- Centre for Systems Chemistry
- Stratingh Institute for Chemistry
- University of Groningen
- Groningen
- The Netherlands
| | - Peter van der Meer
- Department of Cardiology
- University of Groningen
- University Medical Centre Groningen
- 9713 GZ Groningen
- The Netherlands
| | - Wiktor Szymański
- Centre for Systems Chemistry
- Stratingh Institute for Chemistry
- University of Groningen
- Groningen
- The Netherlands
| | - Ben L. Feringa
- Centre for Systems Chemistry
- Stratingh Institute for Chemistry
- University of Groningen
- Groningen
- The Netherlands
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Mitchell DE, Martineau É, Tazerart S, Araya R. Probing Single Synapses via the Photolytic Release of Neurotransmitters. Front Synaptic Neurosci 2019; 11:19. [PMID: 31354469 PMCID: PMC6640007 DOI: 10.3389/fnsyn.2019.00019] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Accepted: 06/24/2019] [Indexed: 11/13/2022] Open
Abstract
The development of two-photon microscopy has revolutionized our understanding of how synapses are formed and how they transform synaptic inputs in dendritic spines-tiny protrusions that cover the dendrites of pyramidal neurons that receive most excitatory synaptic information in the brain. These discoveries have led us to better comprehend the neuronal computations that take place at the level of dendritic spines as well as within neuronal circuits with unprecedented resolution. Here, we describe a method that uses a two-photon (2P) microscope and 2P uncaging of caged neurotransmitters for the activation of single and multiple spines in the dendrites of cortical pyramidal neurons. In addition, we propose a cost-effective description of the components necessary for the construction of a one laser source-2P microscope capable of nearly simultaneous 2P uncaging of neurotransmitters and 2P calcium imaging of the activated spines and nearby dendrites. We provide a brief overview on how the use of these techniques have helped researchers in the last 15 years unravel the function of spines in: (a) information processing; (b) storage; and (c) integration of excitatory synaptic inputs.
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Affiliation(s)
- Diana E. Mitchell
- Department of Neurosciences, Faculty of Medicine, University of Montreal, Montreal, QC, Canada
- The CHU Sainte-Justine Research Center, Montreal, QC, Canada
| | - Éric Martineau
- Department of Neurosciences, Faculty of Medicine, University of Montreal, Montreal, QC, Canada
- The CHU Sainte-Justine Research Center, Montreal, QC, Canada
| | - Sabrina Tazerart
- Department of Neurosciences, Faculty of Medicine, University of Montreal, Montreal, QC, Canada
- The CHU Sainte-Justine Research Center, Montreal, QC, Canada
| | - Roberto Araya
- Department of Neurosciences, Faculty of Medicine, University of Montreal, Montreal, QC, Canada
- The CHU Sainte-Justine Research Center, Montreal, QC, Canada
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Arvin MC, Jin XT, Yan Y, Wang Y, Ramsey MD, Kim VJ, Beckley NA, Henry BA, Drenan RM. Chronic Nicotine Exposure Alters the Neurophysiology of Habenulo-Interpeduncular Circuitry. J Neurosci 2019; 39:4268-4281. [PMID: 30867261 PMCID: PMC6538858 DOI: 10.1523/jneurosci.2816-18.2019] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Revised: 02/11/2019] [Accepted: 03/06/2019] [Indexed: 11/21/2022] Open
Abstract
Antagonism of nicotinic acetylcholine receptors (nAChRs) in the medial habenula (MHb) or interpeduncular nucleus (IPN) triggers withdrawal-like behaviors in mice chronically exposed to nicotine, implying that nicotine dependence involves the sensitization of nicotinic signaling. Identification of receptor and/or neurophysiological mechanisms underlying this sensitization is important, as it could promote novel therapeutic strategies to reduce tobacco use. Using an approach involving photoactivatable nicotine, we previously demonstrated that chronic nicotine (cNIC) potently enhances nAChR function in dendrites of MHb neurons. However, whether cNIC modulates downstream components of the habenulo-interpeduncular (Hb-IP) circuit is unknown. In this study, cNIC-mediated changes to Hb-IP nAChR function were examined in mouse (male and female) brain slices using molecular, electrophysiological, and optical techniques. cNIC enhanced action potential firing and modified spike waveform characteristics in MHb neurons. Nicotine uncaging revealed nAChR functional enhancement by cNIC on proximal axonal membranes. Similarly, nAChR-driven glutamate release from MHb axons was enhanced by cNIC. In IPN, the target structure of MHb axons, neuronal morphology, and nAChR expression is complex, with stronger nAChR function in the rostral subnucleus [rostral IPN (IPR)]. As in MHb, cNIC induced strong upregulation of nAChR function in IPN neurons. This, coupled with cNIC-enhanced nicotine-stimulated glutamate release, was associated with stronger depolarization responses to brief (1 ms) nicotine uncaging adjacent to IPR neurons. Together, these results indicate that chronic exposure to nicotine dramatically alters nicotinic cholinergic signaling and cell excitability in Hb-IP circuits, a key pathway involved in nicotine dependence.SIGNIFICANCE STATEMENT This study uncovers several neuropharmacological alterations following chronic exposure to nicotine in a key brain circuit involved in nicotine dependence. These results suggest that smokers or regular users of electronic nicotine delivery systems (i.e., "e-cigarettes") likely undergo sensitization of cholinergic circuitry in the Hb-IP system. Reducing the activity of Hb-IP nAChRs, either volitionally during smoking cessation or inadvertently via receptor desensitization during nicotine intake, may be a key trigger of withdrawal in nicotine dependence. Escalation of nicotine intake in smokers, or tolerance, may involve stimulation of these sensitized cholinergic pathways. Smoking cessation therapeutics are only marginally effective, and by identifying cellular/receptor mechanisms of nicotine dependence, our results take a step toward improved therapeutic approaches for this disorder.
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Affiliation(s)
- Matthew C Arvin
- Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, Illinois 60611
| | - Xiao-Tao Jin
- Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, Illinois 60611
| | - Yijin Yan
- Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, Illinois 60611
| | - Yong Wang
- Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, Illinois 60611
| | - Matthew D Ramsey
- Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, Illinois 60611
| | - Veronica J Kim
- Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, Illinois 60611
| | - Nicole A Beckley
- Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, Illinois 60611
| | - Brittany A Henry
- Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, Illinois 60611
| | - Ryan M Drenan
- Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, Illinois 60611
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Mu C, Shi M, Liu P, Chen L, Marriott G. Daylight-Mediated, Passive, and Sustained Release of the Glaucoma Drug Timolol from a Contact Lens. ACS CENTRAL SCIENCE 2018; 4:1677-1687. [PMID: 30648151 PMCID: PMC6311683 DOI: 10.1021/acscentsci.8b00641] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/10/2018] [Indexed: 05/24/2023]
Abstract
Timolol, a potent inhibitor of β-adrenergic receptors (βARs), is a first-line drug for decreasing the intraocular pressure (IOP) of patients with glaucoma. Timolol is administered using 0.5% eye-drop solutions at >3 × 107 times the inhibitory concentration (k i) for βARs. This high dose is wasteful and triggers off-target effects that increase medication noncompliance. Here, we introduce contact lenses that release timolol to the eye throughout the day during passive exposures to natural daylight at a more therapeutically relevant concentration (>3000 k i). Timolol is coupled to the polymer of the contact lens via a photocleavable caged cross-linker and is released exclusively to the surrounding fluid after the 400-430 nm mediated cleavage of the cross-linking group. Studies conducted in a preclinical mouse model of glaucoma show photoreleased timolol is effective as authentic timolol in reducing IOP. Our studies highlight several advantages of daylight-mediated release of timolol from lenses compared to eye-drops. First, fitted contact lenses exposed to natural daylight release sufficient timolol to sustain the inhibition of βARs over a 10 h period. Second, the contact lenses inhibit βARs in the eye using only 5.7% of the timolol within a single eye-drop. Third, the lenses allow the patient to passively control the amount of timolol released from the lens-for example, early morning exposure to outdoor sunlight would release enough timolol to maximally reduce the IOP, whereas subsequent periodic exposures to indoor daylight would release sufficient timolol to overcome the effects of its spontaneous dissociation from βARs. Fourth, our lenses are disposable, designed for single day use, and manufactured at a low cost.
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Affiliation(s)
- Changhua Mu
- Department
of Bioengineering, Tsinghua-Berkeley Shenzhen Institute, and Center for Eye
Disease and Development, Vision Science Graduate Program and School
of Optometry, University of California—Berkeley, Berkeley, California 94720, United States
| | - Meng Shi
- Department
of Bioengineering, Tsinghua-Berkeley Shenzhen Institute, and Center for Eye
Disease and Development, Vision Science Graduate Program and School
of Optometry, University of California—Berkeley, Berkeley, California 94720, United States
| | - Ping Liu
- Department
of Bioengineering, Tsinghua-Berkeley Shenzhen Institute, and Center for Eye
Disease and Development, Vision Science Graduate Program and School
of Optometry, University of California—Berkeley, Berkeley, California 94720, United States
| | - Lu Chen
- Department
of Bioengineering, Tsinghua-Berkeley Shenzhen Institute, and Center for Eye
Disease and Development, Vision Science Graduate Program and School
of Optometry, University of California—Berkeley, Berkeley, California 94720, United States
| | - Gerard Marriott
- Department
of Bioengineering, Tsinghua-Berkeley Shenzhen Institute, and Center for Eye
Disease and Development, Vision Science Graduate Program and School
of Optometry, University of California—Berkeley, Berkeley, California 94720, United States
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