title: The Rapidly Acting Antidepressant Ketamine and the mGlu2/3 Receptor Antagonist LY341495 Rapidly Engage Dopaminergic Mood Circuits.
abstract: Ketamine is a rapidly acting antidepressant in patients with treatment-resistant depression (TRD). Although the mechanisms underlying these effects are not fully established, inquiry to date has focused on the triggering of synaptogenesis transduction pathways via glutamatergic mechanisms. Preclinical data suggest that blockade of metabotropic glutamate (mGlu2/3) receptors shares many overlapping features and mechanisms with ketamine and may also provide rapid efficacy for TRD patients. Central dopamine circuitry is recognized as an end target for mood regulation and hedonic valuation and yet has been largely neglected in mechanistic studies of antidepressant-relevant effects of ketamine. Herein, we evaluated the changes in dopaminergic neurotransmission after acute administration of ketamine and the mGlu2/3 receptor antagonist LY341495 [(2S)-2-amino-2-[(1S,2S)-2-carboxycycloprop-1-yl]-3-(xanth-9-yl) propanoic acid ] in preclinical models using electrophysiologic, neurochemical, and behavioral endpoints. When given acutely, both ketamine and LY341495, but not the selective serotonin reuptake inhibitor (SSRI) citalopram, increased the number of spontaneously active dopamine neurons in the ventral tegmental area (VTA), increased extracellular levels of dopamine in the nucleus accumbens and prefrontal cortex, and enhanced the locomotor stimulatory effects of the dopamine D2/3 receptor agonist quinpirole. Further, both ketamine and LY341495 reduced immobility time in the tail-suspension assay in CD1 mice, which are relatively resistant to SSRI antidepressants. Both the VTA neuronal activation and the antidepressant phenotype induced by ketamine and LY341495 were attenuated by the α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor antagonist 1,2,3,4-tetrahydro-6-nitro-2,3-dioxo- (9CI)-benzo[f]quinoxaline-7-sulfonamide, indicating AMPA-dependent effects. These findings provide another overlapping mechanism of action of ketamine and mGlu2/3 receptor antagonism that differentiates them from conventional antidepressants and thus support the potential rapidly acting antidepressant actions of mGlu2/3 receptor antagonism in patients.
authors.affiliation: Departments of Neuroscience and Discovery Chemistry, Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, Indiana (J.M.W., J.A.M., D.D.S., X.L., C.O., B.J., K.R., L.M.R.-K.), and Windlesham, Surrey, UK (S.N.M., G.C.) jwitkin@lilly.com.
authors.forename: J M
authors.initials: JM
authors.lastname: Witkin
authors.affiliation: Departments of Neuroscience and Discovery Chemistry, Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, Indiana (J.M.W., J.A.M., D.D.S., X.L., C.O., B.J., K.R., L.M.R.-K.), and Windlesham, Surrey, UK (S.N.M., G.C.).
authors.forename: J A
authors.initials: JA
authors.lastname: Monn
authors.affiliation: Departments of Neuroscience and Discovery Chemistry, Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, Indiana (J.M.W., J.A.M., D.D.S., X.L., C.O., B.J., K.R., L.M.R.-K.), and Windlesham, Surrey, UK (S.N.M., G.C.).
authors.forename: D D
authors.initials: DD
authors.lastname: Schoepp
authors.affiliation: Departments of Neuroscience and Discovery Chemistry, Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, Indiana (J.M.W., J.A.M., D.D.S., X.L., C.O., B.J., K.R., L.M.R.-K.), and Windlesham, Surrey, UK (S.N.M., G.C.).
authors.forename: X
authors.initials: X
authors.lastname: Li
authors.affiliation: Departments of Neuroscience and Discovery Chemistry, Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, Indiana (J.M.W., J.A.M., D.D.S., X.L., C.O., B.J., K.R., L.M.R.-K.), and Windlesham, Surrey, UK (S.N.M., G.C.).
authors.forename: C
authors.initials: C
authors.lastname: Overshiner
authors.affiliation: Departments of Neuroscience and Discovery Chemistry, Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, Indiana (J.M.W., J.A.M., D.D.S., X.L., C.O., B.J., K.R., L.M.R.-K.), and Windlesham, Surrey, UK (S.N.M., G.C.).
authors.forename: S N
authors.initials: SN
authors.lastname: Mitchell
authors.affiliation: Departments of Neuroscience and Discovery Chemistry, Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, Indiana (J.M.W., J.A.M., D.D.S., X.L., C.O., B.J., K.R., L.M.R.-K.), and Windlesham, Surrey, UK (S.N.M., G.C.).
authors.forename: G
authors.initials: G
authors.lastname: Carter
authors.affiliation: Departments of Neuroscience and Discovery Chemistry, Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, Indiana (J.M.W., J.A.M., D.D.S., X.L., C.O., B.J., K.R., L.M.R.-K.), and Windlesham, Surrey, UK (S.N.M., G.C.).
authors.forename: B
authors.initials: B
authors.lastname: Johnson
authors.affiliation: Departments of Neuroscience and Discovery Chemistry, Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, Indiana (J.M.W., J.A.M., D.D.S., X.L., C.O., B.J., K.R., L.M.R.-K.), and Windlesham, Surrey, UK (S.N.M., G.C.).
authors.forename: K
authors.initials: K
authors.lastname: Rasmussen
authors.affiliation: Departments of Neuroscience and Discovery Chemistry, Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, Indiana (J.M.W., J.A.M., D.D.S., X.L., C.O., B.J., K.R., L.M.R.-K.), and Windlesham, Surrey, UK (S.N.M., G.C.).
authors.forename: L M
authors.initials: LM
authors.lastname: Rorick-Kehn
mesh_terms: D000200:Action Potentials / Q000187:drug effects; D000596:Amino Acids / Q000494:pharmacology*; D000818:Animals; D000928:Antidepressive Agents / Q000494:pharmacology*; D004298:Dopamine / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology; D007649:Ketamine / Q000494:pharmacology*; D008297:Male; D008807:Mice, Inbred BALB C; D017551:Microdialysis; D009043:Motor Activity / Q000187:drug effects; D009474:Neurons / Q000187:drug effects / Q000378:metabolism; D009714:Nucleus Accumbens / Q000187:drug effects / Q000378:metabolism; D017397:Prefrontal Cortex / Q000187:drug effects / Q000378:metabolism; D011810:Quinoxalines / Q000494:pharmacology; D017208:Rats, Wistar; D018091:Receptors, AMPA / Q000037:antagonists & inhibitors; D018094:Receptors, Metabotropic Glutamate / Q000037:antagonists & inhibitors*; D017557:Ventral Tegmental Area / Q000187:drug effects / Q000378:metabolism; D014966:Xanthenes / Q000494:pharmacology*
chemical_list: D000596:Amino Acids; D000928:Antidepressive Agents; D018691:Excitatory Amino Acid Antagonists; C114624:LY 341495; D011810:Quinoxalines; D018091:Receptors, AMPA; D018094:Receptors, Metabotropic Glutamate; D014966:Xanthenes; C108822:metabotropic glutamate receptor 2; C102718:metabotropic glutamate receptor 3; C062865:2,3-dioxo-6-nitro-7-sulfamoylbenzo(f)quinoxaline; D007649:Ketamine; D004298:Dopamine