Cognitive effects of dopaminergic and glutamatergic blockade in nucleus accumbens in pigeons.
In earlier studies it was found that glutamatergic transmission within the nucleus accumbens septi is involved in the performance of a learned visual shape discrimination in pigeons. This study examines what effects several kinds of glutamate and dopamine antagonists have on the same task. Pigeons were trained with the relevant discrimination, bilaterally implanted with cannulas into the nucleus accumbens and tested after various transmission blockers had been administered intracerebrally. SCH-23390, a D1 dopamine antagonist, at the dose used, had no effect, and Spiperone, a D2-dopamine and 5HT2a-serotonine antagonist, significantly decreased the error repeat trials. CNQX, a non-NMDA glutamate receptor antagonist, and Cycloleucine, an antagonist of the glycine allosteric site of NMDA receptors, had no effect. CGS-19755, a selective competitive NMDA antagonist, significantly impaired performance by significantly decreasing the percent correct trials and increasing the error repeat trials. CPPG, a II/III metabotropic glutamate antagonist, remarkably improved performance. MMPG, a III/II metabotropic glutamate antagonist, at the dose used, did not have any significant effect. The preparation employed may be a useful animal model of perceptual disturbances in schizophrenia.
Laboratorio de Neurociencias y Psicología Experimental (IMBECU-CONICET), Dept. Patología, F.C.M., U. N. de Cuyo, y Universidad Católica Argentina, Mendoza (5500), Argentina. gargiulo@lab.cricyt.edu.ar
P A
PA
Gargiulo
M J
MJ
Acerbo
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Krug
J D
JD
Delius
D018750:6-Cyano-7-nitroquinoxaline-2,3-dione / Q000494:pharmacology; D000409:Alanine / Q000031:analogs & derivatives / Q000494:pharmacology; D000818:Animals; D001552:Benzazepines / Q000494:pharmacology; D003071:Cognition / Q000187:drug effects*; D010856:Columbidae; D003515:Cycloleucine / Q000494:pharmacology; D004193:Discrimination Learning / Q000187:drug effects; D018492:Dopamine Antagonists / Q000494:pharmacology*; D065127:Dopamine D2 Receptor Antagonists; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology*; D005998:Glycine / Q000031:analogs & derivatives / Q000494:pharmacology; D009714:Nucleus Accumbens / Q000187:drug effects* / Q000378:metabolism; D010875:Pipecolic Acids / Q000494:pharmacology; D011897:Random Allocation; D044402:Receptor, Serotonin, 5-HT2A / Q000378:metabolism; D017447:Receptors, Dopamine D1 / Q000037:antagonists & inhibitors / Q000378:metabolism; D017448:Receptors, Dopamine D2 / Q000378:metabolism; D018094:Receptors, Metabotropic Glutamate / Q000037:antagonists & inhibitors / Q000378:metabolism; D016194:Receptors, N-Methyl-D-Aspartate / Q000037:antagonists & inhibitors / Q000378:metabolism; D058830:Serotonin 5-HT2 Receptor Antagonists; D013134:Spiperone / Q000494:pharmacology
D001552:Benzazepines; D018492:Dopamine Antagonists; D065127:Dopamine D2 Receptor Antagonists; D018691:Excitatory Amino Acid Antagonists; D010875:Pipecolic Acids; D044402:Receptor, Serotonin, 5-HT2A; D017447:Receptors, Dopamine D1; D017448:Receptors, Dopamine D2; D018094:Receptors, Metabotropic Glutamate; D016194:Receptors, N-Methyl-D-Aspartate; D058830:Serotonin 5-HT2 Receptor Antagonists; C101185:alpha-methyl-4-phosphonophenylglycine; C104331:cyclopropyl-4-phosphonophenylglycine; D003515:Cycloleucine; C053672:selfotel; D013134:Spiperone; D018750:6-Cyano-7-nitroquinoxaline-2,3-dione; D000409:Alanine; D005998:Glycine