Involvement of the basolateral amygdala in muscarinic cholinergic modulation of extinction memory consolidation.
Previous studies have reported that drugs affecting neuromodulatory systems within the basolateral amygdala (BLA), including drugs affecting muscarinic cholinergic receptors, modulate the consolidation of many kinds of training, including contextual fear conditioning (CFC). The present experiments investigated the involvement of muscarinic cholinergic influences within the BLA in modulating the consolidation of CFC extinction memory. Male Sprague Dawley rats implanted with unilateral cannula aimed at the BLA were trained on a CFC task, using footshock stimulation, and 24 and 48 h later were given extinction training by replacing them in the apparatus without footshock. Following each extinction session they received intra-BLA infusions of the cholinergic agonist oxotremorine (10 ng). Immediate post-extinction BLA infusions significantly enhanced extinction but infusions administered 180 min after extinction training did not influence extinction. Thus the oxotremorine effects were time-dependent and not attributable to non-specific effects on retention performance. These findings provide evidence that, as previously found with original CFC learning, cholinergic activation within the BLA modulates the consolidation of CFC extinction.
Boccia
Mariano M
MM
Laboratorio de Neurofarmacología de los Procesos de Memoria Cátedra de Farmacología, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Argentina.
Blake
Mariano G
MG
Baratti
Carlos M
CM
McGaugh
James L
JL
D000679:Amygdala / Q000187:drug effects / Q000502:physiology*; D000704:Analysis of Variance; D000818:Animals; D003214:Conditioning, Classical; D004597:Electroshock; D004924:Escape Reaction / Q000187:drug effects; D005108:Extinction, Psychological / Q000187:drug effects / Q000502:physiology*; D005239:Fear; D046352:Freezing Reaction, Cataleptic / Q000187:drug effects; D008297:Male; D008568:Memory / Q000187:drug effects / Q000502:physiology*; D018721:Muscarinic Agonists / Q000008:administration & dosage; D010095:Oxotremorine / Q000008:administration & dosage; D051381:Rats; D017207:Rats, Sprague-Dawley; D011976:Receptors, Muscarinic / Q000378:metabolism*
D018721:Muscarinic Agonists; D011976:Receptors, Muscarinic; D010095:Oxotremorine