Acute suppression, but not chronic genetic deficiency, of c-fos gene expression impairs long-term memory in aversive taste learning.
Several lines of evidence have indicated that the establishment of long-term memory requires protein synthesis, including the synthesis of immediate-early gene products. Although the anatomical expression patterns of the c-fos gene, a transcription factor-encoding immediate-early gene, in conditioned taste aversion (CTA) are well documented, the functional roles of c-fos gene expression and Fos-mediated transcription remain to be clarified. Using the antisense oligodeoxynucleotide (AS-ODN) method in rats and gene-targeting knockout techniques in mice (c-fos(-/-) mice), we examined the roles of c-fos gene expression in the acquisition, retrieval, and retention of CTA. Preconditioning microinfusion of AS-ODN directed against c-fos mRNA (c-fos AS-ODN) into the parabrachial nucleus (PBN) impaired the acquisition, whereas infusion of control ODNs consisting of a randomized or inverted base order had no effect. Microinfusion of c-fos AS-ODN into either the amygdala or insular cortex did not impair the acquisition, whereas it attenuated the retention. Retrieval and subsequent retention of an acquired CTA were not disrupted by c-fos AS-ODN infusion into the PBN or amygdala. Microinfusion of another AS-ODN directed against zif268 (egr-1, krox-24, NGFI-A) mRNA into the PBN or amygdala did not affect the acquisition and retention. The genetic deficiency in c-fos(-/-) mice caused normal acquisition and retention. The present results suggest that the Fos-mediated gene transcription in the PBN, amygdala, or insular cortex plays critical roles in the acquisition and/or consolidation, but not the retrieval, of long-term taste memory; nevertheless, some other factors could compensate CTA mechanism when Fos-mediated transcription is not available.
Yasoshima
Yasunobu
Y
Department of Behavioral Physiology, Graduate School of Human Sciences, Osaka University, 1-2 Yamada-oka, Suita 565-0871, Japan.
Sako
Noritaka
N
Senba
Emiko
E
Yamamoto
Takashi
T
D000818:Animals; D001362:Avoidance Learning / Q000502:physiology*; D001522:Behavior, Animal; D051766:Early Growth Response Protein 1 / Q000235:genetics / Q000378:metabolism; D005786:Gene Expression Regulation; D016762:Genes, fos; D008297:Male; D008568:Memory / Q000502:physiology*; D051379:Mice; D018345:Mice, Knockout; D009474:Neurons / Q000166:cytology / Q000378:metabolism; D016376:Oligonucleotides, Antisense / Q000235:genetics / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D013649:Taste; D014158:Transcription, Genetic
D051766:Early Growth Response Protein 1; C486109:Egr1 protein, mouse; D016376:Oligonucleotides, Antisense