Memory-influencing intra-basolateral amygdala drug infusions modulate expression of Arc protein in the hippocampus.
Activation of beta-adrenoceptors in the basolateral complex of the amygdala (BLA) modulates memory storage processes and long-term potentiation in downstream targets of BLA efferents, including the hippocampus. Here, we show that this activation also increases hippocampal levels of activity-regulated cytoskeletal protein (Arc), an immediate-early gene (also termed Arg 3.1) implicated in hippocampal synaptic plasticity and memory consolidation processes. Infusions of the beta-adrenoreceptor agonist, clenbuterol, into the BLA immediately after training on an inhibitory avoidance task enhanced memory tested 48 h later. The same dose of clenbuterol significantly increased Arc protein levels in the dorsal hippocampus. Additionally, posttraining intra-BLA infusions of a memory-impairing dose of lidocaine significantly reduced Arc protein levels in the dorsal hippocampus. Increases in Arc protein levels were not accompanied by increases in Arc mRNA, suggesting that amygdala modulation of Arc protein and synaptic plasticity in efferent brain regions occurs at a posttranscriptional level. Finally, infusions of Arc antisense oligodeoxynucleotides into the dorsal hippocampus impaired performance of an inhibitory avoidance task, indicating that the changes in Arc protein expression are related to the observed changes in memory performance.
McIntyre
Christa K
CK
Center for the Neurobiology of Learning and Memory, and Department of Neurobiology and Behavior, 218 Bonney Research Laboratory, University of California, Irvine, CA 92697-3800, USA. cmcintyr@uci.edu
Miyashita
Teiko
T
Setlow
Barry
B
Marjon
Kristopher D
KD
Steward
Oswald
O
Guzowski
John F
JF
McGaugh
James L
JL
D000318:Adrenergic beta-Agonists / Q000494:pharmacology*; D000679:Amygdala / Q000378:metabolism*; D000704:Analysis of Variance; D000818:Animals; D051017:Apoptosis Regulatory Proteins / Q000235:genetics / Q000378:metabolism*; D001362:Avoidance Learning / Q000187:drug effects; D002976:Clenbuterol / Q000494:pharmacology*; D005786:Gene Expression Regulation / Q000187:drug effects*; D006624:Hippocampus / Q000378:metabolism*; D015151:Immunoblotting; D017404:In Situ Hybridization, Fluorescence; D008012:Lidocaine / Q000494:pharmacology; D008297:Male; D008568:Memory / Q000187:drug effects*; D009124:Muscle Proteins / Q000235:genetics / Q000378:metabolism*; D020319:Oligodeoxyribonucleotides, Antisense / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley
D000318:Adrenergic beta-Agonists; D051017:Apoptosis Regulatory Proteins; D009124:Muscle Proteins; C491788:Nol3 protein, rat; D020319:Oligodeoxyribonucleotides, Antisense; D008012:Lidocaine; D002976:Clenbuterol