title: Extending the duration of long-term memories: Interactions between environmental darkness and retinoid signaling.
abstract: Retinoid signaling plays an important role in hippocampal-dependent vertebrate memories. However, we have previously demonstrated that retinoids are also involved in the formation of long-term implicit memory following operant conditioning of the invertebrate mollusc Lymnaea stagnalis. Furthermore, we have discovered an interaction between environmental light/dark conditions and retinoid signaling and the ability of both to convert intermediate-term memory into long-term memory. In this study, we extend these findings to show that retinoid receptor agonists and environmental darkness can both also extend the duration of long-term memory. Interestingly, exposure to constant environmental darkness significantly increased the expression of retinoid receptors in the adult central nervous system, as well as induced specific changes in a key neuron mediating the conditioned behaviour. These studies not only shed more light on how retinoids influence memory formation, but also further link environmental light conditions to the retinoid signaling pathway.
authors.affiliation: Dept. Biological Sciences, Brock University, 1812 Sir Isaac Brock's Way, St. Catharines, Ontario L2S 3A1, Canada.
authors.forename: Sevanne
authors.initials: S
authors.lastname: Carpenter
authors.affiliation: Dept. Biological Sciences, Brock University, 1812 Sir Isaac Brock's Way, St. Catharines, Ontario L2S 3A1, Canada.
authors.forename: Cailin M
authors.initials: CM
authors.lastname: Rothwell
authors.affiliation: Dept. Biological Sciences, Brock University, 1812 Sir Isaac Brock's Way, St. Catharines, Ontario L2S 3A1, Canada.
authors.forename: Michelle L
authors.initials: ML
authors.lastname: Wright
authors.affiliation: Dept. Biological Sciences, Brock University, 1812 Sir Isaac Brock's Way, St. Catharines, Ontario L2S 3A1, Canada.
authors.forename: Eric
authors.initials: E
authors.lastname: de Hoog
authors.affiliation: Dept. Biological Sciences, Brock University, 1812 Sir Isaac Brock's Way, St. Catharines, Ontario L2S 3A1, Canada.
authors.forename: Sarah
authors.initials: S
authors.lastname: Walker
authors.affiliation: Dept. Biological Sciences, Brock University, 1812 Sir Isaac Brock's Way, St. Catharines, Ontario L2S 3A1, Canada.
authors.forename: Emma
authors.initials: E
authors.lastname: Hudson
authors.affiliation: Dept. Biological Sciences, Brock University, 1812 Sir Isaac Brock's Way, St. Catharines, Ontario L2S 3A1, Canada. Electronic address: gspencer@brocku.ca.
authors.forename: Gaynor E
authors.initials: GE
authors.lastname: Spencer
mesh_terms: D015081:2-Naphthylamine / Q000031:analogs & derivatives / Q000494:pharmacology; D000818:Animals; D001522:Behavior, Animal; D001565:Benzoates / Q000494:pharmacology; D047188:Chalcones / Q000494:pharmacology; D003216:Conditioning, Operant / Q000187:drug effects / Q000502:physiology*; D003624:Darkness; D004777:Environment; D008195:Lymnaea; D057567:Memory, Long-Term / Q000187:drug effects / Q000502:physiology*; D011743:Pyrimidines / Q000494:pharmacology; D047488:Retinoid X Receptors / Q000819:agonists*; D012176:Retinoids / Q000378:metabolism* / Q000494:pharmacology; D015398:Signal Transduction / Q000502:physiology*; D013764:Tetrahydronaphthalenes / Q000494:pharmacology
chemical_list: D001565:Benzoates; D047188:Chalcones; C542239:EC23 compound; C000608768:PA024 compound; D011743:Pyrimidines; D047488:Retinoid X Receptors; D012176:Retinoids; D013764:Tetrahydronaphthalenes; C087130:SR 11237; C054189:3,5-di-tert-butylchalcone 4'-carboxylic acid; D015081:2-Naphthylamine
keywords: Electrophysiology; Invertebrate learning; Lymnaea stagnalis; Operant conditioning; Retinoic acid