title: Nucleus accumbens-specific interventions in RGS9-2 activity modulate responses to morphine.
abstract: Regulator of G protein signalling 9-2 (Rgs9-2) modulates the actions of a wide range of CNS-acting drugs by controlling signal transduction of several GPCRs in the striatum. RGS9-2 acts via a complex mechanism that involves interactions with Gα subunits, the Gβ5 protein, and the adaptor protein R7BP. Our recent work identified Rgs9-2 complexes in the striatum associated with acute or chronic exposures to mu opioid receptor (MOR) agonists. In this study we use several new genetic tools that allow manipulations of Rgs9-2 activity in particular brain regions of adult mice in order to better understand the mechanism via which this protein modulates opiate addiction and analgesia. We used adeno-associated viruses (AAVs) to express forms of Rgs9-2 in the dorsal and ventral striatum (nucleus accumbens, NAc) in order to examine the influence of this protein in morphine actions. Consistent with earlier behavioural findings from constitutive Rgs9 knockout mice, we show that Rgs9-2 actions in the NAc modulate morphine reward and dependence. Notably, Rgs9-2 in the NAc affects the analgesic actions of morphine as well as the development of analgesic tolerance. Using optogenetics we demonstrate that activation of Channelrhodopsin2 in Rgs9-2-expressing neurons, or in D1 dopamine receptor (Drd1)-enriched medium spiny neurons, accelerates the development of morphine tolerance, whereas activation of D2 dopamine receptor (Drd2)-enriched neurons does not significantly affect the development of tolerance. Together, these data provide new information on the signal transduction mechanisms underlying opiate actions in the NAc.
authors.affiliation: Department of Basic Sciences, Faculty of Medicine, University of Crete, Heraklion, Greece.
authors.forename: Sevasti
authors.initials: S
authors.lastname: Gaspari
authors.affiliation: Department of Basic Sciences, Faculty of Medicine, University of Crete, Heraklion, Greece.
authors.forename: Maria M
authors.initials: MM
authors.lastname: Papachatzaki
authors.affiliation: Fishberg Department of Neuroscience, Icahn School of Medicine at Mount Sinai, Friedman Brain Institute, New York, NY, USA.
authors.forename: Ja Wook
authors.initials: JW
authors.lastname: Koo
authors.affiliation: Fishberg Department of Neuroscience, Icahn School of Medicine at Mount Sinai, Friedman Brain Institute, New York, NY, USA.
authors.forename: Fiona B
authors.initials: FB
authors.lastname: Carr
authors.affiliation: Department of Basic Sciences, Faculty of Medicine, University of Crete, Heraklion, Greece.
authors.forename: Maria-Efstratia
authors.initials: ME
authors.lastname: Tsimpanouli
authors.affiliation: Department of Basic Sciences, Faculty of Medicine, University of Crete, Heraklion, Greece.
authors.forename: Eugenia
authors.initials: E
authors.lastname: Stergiou
authors.affiliation: Fishberg Department of Neuroscience, Icahn School of Medicine at Mount Sinai, Friedman Brain Institute, New York, NY, USA.
authors.forename: Rosemary C
authors.initials: RC
authors.lastname: Bagot
authors.affiliation: Fishberg Department of Neuroscience, Icahn School of Medicine at Mount Sinai, Friedman Brain Institute, New York, NY, USA.
authors.forename: Deveroux
authors.initials: D
authors.lastname: Ferguson
authors.affiliation: Fishberg Department of Neuroscience, Icahn School of Medicine at Mount Sinai, Friedman Brain Institute, New York, NY, USA.
authors.forename: Ezekiell
authors.initials: E
authors.lastname: Mouzon
authors.affiliation: Division of Chemical Biology, Indian Institute of Chemical Technology, Hyderabad, India.
authors.forename: Sumana
authors.initials: S
authors.lastname: Chakravarty
authors.affiliation: Departments of Bioengineering and Physiology and Behavioural Sciences, Stanford Univerity, Stanford, CA, USA.
authors.forename: Karl
authors.initials: K
authors.lastname: Deisseroth
authors.affiliation: Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD, USA.
authors.forename: Mary Kay
authors.initials: MK
authors.lastname: Lobo
authors.affiliation: 1] Department of Basic Sciences, Faculty of Medicine, University of Crete, Heraklion, Greece [2] Fishberg Department of Neuroscience, Icahn School of Medicine at Mount Sinai, Friedman Brain Institute, New York, NY, USA [3] Department of Pharmacology and Systems Therapeutics, Icahn School of Medicine at Mount Sinai, New York, NY, USA.
authors.forename: Venetia
authors.initials: V
authors.lastname: Zachariou
mesh_terms: D000701:Analgesics, Opioid / Q000494:pharmacology*; D000818:Animals; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D009020:Morphine / Q000494:pharmacology*; D017072:Neostriatum / Q000187:drug effects / Q000378:metabolism; D009474:Neurons / Q000378:metabolism*; D009714:Nucleus Accumbens / Q000187:drug effects* / Q000378:metabolism*; D062308:Optogenetics; D020710:RGS Proteins / Q000378:metabolism*; D017447:Receptors, Dopamine D1 / Q000378:metabolism; D017448:Receptors, Dopamine D2 / Q000378:metabolism; D012201:Reward; D015398:Signal Transduction / Q000187:drug effects
chemical_list: D000701:Analgesics, Opioid; D020710:RGS Proteins; D017447:Receptors, Dopamine D1; D017448:Receptors, Dopamine D2; C116925:regulator of g-protein signaling 9; D009020:Morphine