Differential effects of muscarinic receptor blockade in prelimbic cortex on acquisition and memory formation of an odor-reward task.
The present experiments determined the consequences of blocking muscarinic cholinergic receptors of the prelimbic (PL) cortex in the acquisition and retention of an odor-reward associative task. Rats underwent a training test (five trials) and a 24-h retention test (two retention trials and two relearning trials). In the first experiment, rats were bilaterally infused with scopolamine (20 or 5 microg/site) prior to training. Although scopolamine rats showed acquisition equivalent to PBS-injected controls, they exhibited weakened performance in the 24-h retention test measured by number of errors. In the second experiment, rats were injected with scopolamine (20 microg/site) immediately or 1 h after training and tested 24 h later. Scopolamine rats injected immediately showed severe amnesia detected in two performance measures (errors and latencies), demonstrating deficits in retention and relearning, whereas those injected 1 h later showed good 24-h test performance, similar to controls. These results suggest that muscarinic transmission in the PL cortex is essential for early memory formation, but not for acquisition, of a rapidly learned odor discrimination task. Findings corroborate the role of acetylcholine in consolidation processes and the participation of muscarinic receptors in olfactory associative tasks.
Carballo-Márquez
Anna
A
Departament de Psicobiologia i Metodologia de les Ciències de la Salut, Institut de Neurociències, Universitat Autònoma de Barcelona, Barcelona, Spain.
Vale-Martínez
Anna
A
Guillazo-Blanch
Gemma
G
Torras-Garcia
Meritxell
M
Boix-Trelis
Núria
N
Martí-Nicolovius
Margarita
M
D000647:Amnesia / Q000139:chemically induced; D000818:Animals; D001245:Association Learning / Q000187:drug effects / Q000502:physiology; D001522:Behavior, Animal / Q000187:drug effects / Q000502:physiology; D002540:Cerebral Cortex / Q000187:drug effects / Q000502:physiology*; D004192:Discrimination, Psychological; D004334:Drug Administration Schedule; D007267:Injections; D007858:Learning / Q000187:drug effects / Q000502:physiology*; D008297:Male; D008568:Memory / Q000187:drug effects / Q000502:physiology*; D018727:Muscarinic Antagonists / Q000008:administration & dosage / Q000494:pharmacology; D009812:Odorants; D051381:Rats; D017208:Rats, Wistar; D011976:Receptors, Muscarinic / Q000502:physiology*; D012153:Retention, Psychology / Q000187:drug effects / Q000502:physiology; D012201:Reward; D012601:Scopolamine / Q000008:administration & dosage / Q000494:pharmacology
D018727:Muscarinic Antagonists; D011976:Receptors, Muscarinic; D012601:Scopolamine