title: Effects of metabotropic glutamate receptor 2/3 agonism and antagonism on schizophrenia-like cognitive deficits induced by phencyclidine in rats.
abstract: Dysregulation of glutamate neurotransmission may play a role in cognitive deficits in schizophrenia. Manipulation of glutamate signaling using drugs acting at metabotropic glutamate receptors has been suggested as a novel approach to treating schizophrenia-related cognitive dysfunction. We examined how the metabotropic glutamate receptor 2/3 agonist LY379268 and the metabotropic glutamate receptor 2/3 antagonist LY341495 altered phencyclidine-induced disruptions in performance in the 5-choice serial reaction time task. This test assesses multiple cognitive modalities characteristically impaired in schizophrenia that are disrupted by phencyclidine administration. Acute LY379268 alone did not affect 5-choice serial reaction time task performance, except for nonspecific response suppression at high doses. Acute LY379268 administration exacerbated phencyclidine-induced disruption of attentional performance in this task, while acute LY341495 did not alter 5-choice serial reaction time task performance during phencyclidine exposure. Chronic LY341495 impaired attentional performance in the 5-choice serial reaction time task by itself, but attenuated phencyclidine-induced excessive timeout responding. The mixed effects of metabotropic glutamate receptor 2/3 agonism and antagonism on cognitive performance under baseline conditions and after disruption with phencyclidine demonstrate that different aspects of cognition may respond differently to a given pharmacological manipulation, indicating that potential antipsychotic or pro-cognitive medications need to be tested for their effects on a range of cognitive modalities. Our findings also suggest that additional mechanisms, besides cortical glutamatergic transmission, may be involved in certain cognitive dysfunctions in schizophrenia.
authors.affiliation: Department of Psychiatry, School of Medicine, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA.
authors.forename: Nurith
authors.initials: N
authors.lastname: Amitai
authors.forename: Athina
authors.initials: A
authors.lastname: Markou
mesh_terms: D000596:Amino Acids / Q000494:pharmacology / Q000627:therapeutic use; D000818:Animals; D014150:Antipsychotic Agents / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology / Q000627:therapeutic use; D019086:Bridged Bicyclo Compounds, Heterocyclic / Q000494:pharmacology / Q000627:therapeutic use; D003071:Cognition / Q000187:drug effects* / Q000502:physiology; D018683:Excitatory Amino Acid Agents / Q000145:classification / Q000494:pharmacology / Q000627:therapeutic use; D008297:Male; D010622:Phencyclidine / Q000008:administration & dosage / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar; D018094:Receptors, Metabotropic Glutamate / Q000819:agonists* / Q000037:antagonists & inhibitors* / Q000378:metabolism; D012559:Schizophrenia / Q000139:chemically induced / Q000378:metabolism*; D013997:Time Factors; D014966:Xanthenes / Q000494:pharmacology / Q000627:therapeutic use
chemical_list: D000596:Amino Acids; D014150:Antipsychotic Agents; D019086:Bridged Bicyclo Compounds, Heterocyclic; D018683:Excitatory Amino Acid Agents; C114624:LY 341495; C118218:LY 379268; D018094:Receptors, Metabotropic Glutamate; D014966:Xanthenes; C108822:metabotropic glutamate receptor 2; C102718:metabotropic glutamate receptor 3; D010622:Phencyclidine