Novel interactive effects of darkness and retinoid signaling in the ability to form long-term memory following aversive operant conditioning.
Neurobiol Learn Mem
; 114: 251-63, 2014 Oct.
Article
em En
| MEDLINE
| ID: mdl-25062644
ABSTRACT
The vitamin A metabolite, retinoic acid, is important for memory formation and hippocampal synaptic plasticity in vertebrate species. In our studies in the mollusc Lymnaea stagnalis, we have shown that retinoic acid plays a role in memory formation following operant conditioning of the aerial respiratory behaviour. Inhibition of either retinaldehyde dehydrogenase (RALDH) or the retinoid receptors prevents long-term memory (LTM) formation, whereas synthetic retinoid receptor agonists promote memory formation by converting intermediate-term memory (ITM) into LTM. In this study, animals were exposed to constant darkness in order to test whether light-sensitive retinoic acid would promote memory formation. However, we found that exposure to constant darkness alone (in the absence of retinoic acid) enhanced memory formation. To determine whether the memory-promoting effects of darkness could override the memory-inhibiting effects of the retinoid signaling inhibitors, we exposed snails to RALDH inhibitors or a retinoid receptor antagonist in constant darkness. We found that darkness overcame the inhibitory effects of RALDH inhibition, but did not overcome the inhibitory effects of the retinoid receptor antagonist. We also tested whether constant darkness and training affected the mRNA levels of the retinoid metabolic enzymes RALDH and Cyp26, or the mRNA levels of the retinoid receptors, but found no significant effect. Overall, these data demonstrate an interaction between environmental light conditions and the retinoid signaling pathway, which influence long-term memory formation in a mollusc.
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Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Transdução de Sinais
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Condicionamento Operante
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Escuridão
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Memória de Longo Prazo
Limite:
Animals
Idioma:
En
Revista:
Neurobiol Learn Mem
Assunto da revista:
BIOLOGIA
/
CIENCIAS DO COMPORTAMENTO
/
NEUROLOGIA
Ano de publicação:
2014
Tipo de documento:
Article
País de afiliação:
Canadá