In vivo pharmacological characterization of the structurally novel, potent, selective mGlu2/3 receptor agonist LY404039 in animal models of psychiatric disorders.
BACKGROUND
Data from both preclinical and clinical studies have provided proof of concept that modulation of limbic and forebrain glutamate, via mGlu2/3 receptor agonists, might provide therapeutic benefits in many psychiatric disorders including schizophrenia and anxiety.


OBJECTIVE
The aim of this study was to assess the efficacy of a structurally novel, potent, selective mGlu2/3 receptor agonist with improved bioavailability (LY404039) in animal models predictive of antipsychotic and anxiolytic efficacy.


METHODS
LY404039 was assessed in amphetamine- and phencyclidine-induced hyperlocomotion, conditioned avoidance responding, fear-potentiated startle, marble burying, and rotarod behavioral tests. Monoamine release and turnover were assessed using microdialysis and ex vivo tissue levels.


RESULTS
LY404039 attenuated amphetamine- and phencyclidine-induced hyperlocomotion (3-30 and 10 mg/kg, respectively). LY404039 (3-10 mg/kg) inhibited conditioned avoidance responding. LY404039 also reduced fear-potentiated startle in rats (3-30 microg/kg) and marble burying in mice (3-10 mg/kg), indicating anxiolytic-like effects. Importantly, LY404039 did not produce sedative effects or motor impairment as measured by rotarod performance and lack of escape failures in the conditioned avoidance task (at doses up to 30 and 10 mg/kg, respectively). LY404039 (10 mg/kg) also increased dopamine and serotonin release/turnover in the prefrontal cortex.


CONCLUSIONS
These results demonstrate the broad preclinical efficacy of LY404039 across multiple animal models of antipsychotic and anxiolytic efficacy. Additionally, this compound modulates mesocortical neurotransmission and provides a novel mechanism for the treatment of psychiatric disorders that may be associated with improved efficacy and reduced incidence of undesirable side effects. As glutamatergic dysfunction has been linked to the etiology of schizophrenia, clinical studies with more potent mGlu2/3 agonists, such as LY404039, may be useful to explore the validity of this hypothesis.
Rorick-Kehn
Linda M
LM
Neuroscience Discovery Research, Lilly Research Laboratories, Eli Lilly and Company, Lilly Corporate Center, DC0510, Indianapolis, IN 46285, USA. RorickKehnLM@lilly.com
Johnson
Bryan G
BG
Knitowski
Karen M
KM
Salhoff
Craig R
CR
Witkin
Jeffrey M
JM
Perry
Kenneth W
KW
Griffey
Kelly I
KI
Tizzano
Joseph P
JP
Monn
James A
JA
McKinzie
David L
DL
Schoepp
Darryle D
DD
D000596:Amino Acids / Q000494:pharmacology; D000661:Amphetamine / Q000494:pharmacology; D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects*; D019086:Bridged Bicyclo Compounds, Heterocyclic / Q000737:chemistry / Q000494:pharmacology* / Q000627:therapeutic use; D003499:Cyclic S-Oxides / Q000737:chemistry / Q000494:pharmacology* / Q000627:therapeutic use; D003975:Diazepam / Q000494:pharmacology; D004195:Disease Models, Animal; D004305:Dose-Response Relationship, Drug; D008297:Male; D001523:Mental Disorders / Q000188:drug therapy* / Q000523:psychology; D051379:Mice; D015394:Molecular Structure; D009043:Motor Activity / Q000187:drug effects; D010622:Phencyclidine / Q000494:pharmacology; D017397:Prefrontal Cortex / Q000187:drug effects / Q000378:metabolism; D051381:Rats; D011916:Rats, Inbred F344; D017207:Rats, Sprague-Dawley; D018094:Receptors, Metabotropic Glutamate / Q000819:agonists* / Q000037:antagonists & inhibitors; D014966:Xanthenes / Q000494:pharmacology
C517803:4-aminho-2-thiabicyclo(3.1.0)hexane-4,6-dicarboxylic acid; D000596:Amino Acids; D019086:Bridged Bicyclo Compounds, Heterocyclic; D003499:Cyclic S-Oxides; C114624:LY 341495; D018094:Receptors, Metabotropic Glutamate; D014966:Xanthenes; C108822:metabotropic glutamate receptor 2; C102718:metabotropic glutamate receptor 3; D000661:Amphetamine; D010622:Phencyclidine; D003975:Diazepam